Chevrolet - Chevy - Service Manual - 1981 - 1981 (2)

CHEVROLET FOREWORD This manual includes procedures fo r diagnosis, maintenance and adjust­ ments, m inor service operations, and removal and installation fo r com­ ponents o f Chevrolet Light D uty Trucks. Procedures involving disassembly and assembly o f major components fo r these vehicles are contained in the 1981 Chevrolet Passenger Car and Light D uty T ruck U n it Repair (Overhaul) Manual. W iring diagrams fo r 1981 trucks are contained in a separate Wiring Diagram Booklet. The Section Index on the contents page enables the user to q u ickly locate any desired section. A t the beginning o f each section containing more than one major subject is a Table o f Contents, which gives the page number on w hich each major subject begins. An index is placed at the beginning o f each m ajor subject w ith in the section. Summaries o f Special Tools, when required, and specifications are found at end o f major sections. When reference is made in this manual to a brand name, number, or specific to o k an equivalent product may be used in place o f the recom­ mended item. This manual should be kept in a handy place fo r ready reference. If pro­ perly used, it w ill enable the technician to better serve the owners o f Chev­ rolet b u ilt vehicles. A ll in fo rm a tio n, illustrations and specifications contained in this literature are based on the latest product in fo rm a tio n available at the tim e o f p u b li­ cation approval. The right is reserved to make changes at any tim e w ith o u t notice. IMPORTANT SAFETY NOTICE Proper service and repair is important to the safe, reliable operation of all motor ve­ hicles. The service procedures recommended by Chevrolet and described in this serv­ ice manual are effective methods of performing service operations. Some of these service operations require the use of tools specially designed for the purpose. The special tools should be used when and as recommended. It is important to note that this manual contains various CAUTIONS, and NOTICES which should be carefully read in order to minimize the risk o f personal injury to service personnel or the possibility that improper service methods will be followed which may damage the vehicle. It also is important to understand that these CAU­ TIONS and NOTICES are not exhaustive. Chevrolet could not possibly know, evaluate and advise the service trade of all conceivable ways in which service might be done or o f the possible hazardous consequences of each way. Consequently, Chev­ rolet has not undertaken any such broad evaluation. Accordingly, anyone who uses a service procedure or tool which is not recommended by Chevrolet must first satisfy himself thoroughly that neither his safety nor the vehicle will be jeopardized by the service method he selects. TABLE OF CONTENTS SECTION GENERAL INFORMATION General In fo rm a tio n M a in te n a n ce and L u brication OA OB HEATING AND AIR CONDITIONING H eating and V e n tila tio n A ir C o n d itio n in g 1981 LIGHT DUTY TRUCK (SERIES 10-35) CHASSIS SERVICE MANUAL 1A 1B FRAME AND BUMPERS Fram e and Body M ounts B u m p e rs Sheet M etal B ody 2A 2B 2C 2D STEERING, SUSPENSION, WHEELS AND TIRES Front A lig n m e n t S te e rin g Linkage M a n u a l S teering P o w e r S te e rin g S te e rin g C o lu m n F ront S uspension Rear S uspension W h eel and Tires 3A 3B1 3B2 3B3 3B4 3C 3D 3E AXLE P ro p e lle r S h a ft and U niversal J o in t Rear A xle F ront W heel D rive BRAKES 4A 4B 4C 5 ENGINE CAUTION These vehicles contains some parts dimensioned in the metric system as well as in the customary system. Some fasteners are metric and are very close in dimension to familiar customary fast­ eners in the inch system. It is important to note that, during any vehicle maintenance procedures, replacement fasteners must have the same measurements and strength as those removed, whether metric or customary. (Numbers on the heads of metric bofts and on surfaces of metric nuts indicate their strength. Customary bolts use radial lines for this purpose, while most customary nuts do not have strength markings.) Mismatched or incorrect fasteners can result in vehicle damage or malfunction, or possibly personal injury. Therefore, fasteners removed from the vehicle should be saved for re-use in the same locations whenever possible. Where the fasteners are not satisfactory for re-use, care should be taken to select a replacement that matches the original. For information and assistance, see your dealer. Engine In-Line 6 S m all Block M ark IV 5.7L(Z) 350 Diesel Engine Cooling Engine Fuel M o d e l 1ME M o d el 2SE M o d el M 2 M E M odel M 4M E Fuel S ystem Engine Electrical Engine Emission Controls Engine Exhaust Engine P erform ance Specifications 6 6A1 6A4 6A5 6A6 6B 6C 6C1 6C2 6C3 6C4 6C5 6D 6E 6F 6G TRANSMISSION A u to m a tic M a nual C lutch T ra n s fe r Case 7A 7B 7C 7E ELECTRICAL — BODY AND CHASSIS Lam ps and L ig h tin g Electrical and Wiring 8A 8B In s tru m e n t Panel and Gages 8C ACCESSORIES METRIC AND FASTENER INFORMATION © 1980 General Motors Corporation 9 10 P r in te d in U . S .A . GENERAL INFORMATION OA-1 SECTION OA GENERAL INFORMATION CONTENTS OF THIS SECTION G e n e ra l.................................................................................................................... Vehicle Identification N u m b e r......................................................................... Service Parts Identification S tic k e r................................................................. Vehicle L o a d in g .................................................................................................... Engine Code N u m b e r......................................................................................... U nit and Serial N um ber L ocations................................................................. 0-1 0-2 0-3 0-3 0-3 0-3 GENERAL VEHICLE IDENTIFICATION NUMBER (VIN) Inform ation to identify the vehicle and vehicle compo­ nents appears in this section. Detailed specifications on m ajor units are given at the end of each respective section in this manual. This is the legal identification of the vehicle. It appears on a plate which is attached to the left top of the instrum ent panel on CK and G truck and can be easily seen through the windshield from outside the vehicle (Fig. 0A-1). On P10-2030 models, the plate is attached to the front of the dash and toe panel to the left of steering column (Fig. 0A -2). The V IN also appears on the Vehicle Certificates of Title and Registration. MFD. BY GENERAL MOTORS CORPORATION CAWR GAV,R REAR INFLATION DATA FOR TIRES FURNISHED WITH VEHICLE S H O W N ON V E H I C L E C E R T I F I C A T I O N L A B E L Q W A R R A N T Y V O ID E D IF L 0 A 0 E 0 IN E X C E S S OF R A T IN G S Q SE E O W N E R S M A N U A L FO R O T H E R L O A D IN G A N D IN F L A T IO N D A T A EXAMPLE ONL Y and G) Fig. 0A-2--V.I.N. Rating Plate (P Model) LIG H T T R U C K SERVICE M A N U A L OA-2 GENERAL INFORMATION VEHICLE IDENTIFICATION NUMBER 1GCEC14 0 9BF123456 NA TIO N OF ORIGIN 1 U .S .A . 2 CANADA PLANT SEQUENTIAL NUMBER MODEL YEAR ASSEMBLY PLANT CODE M ANUFACTURER G G E N E R A L M O TO RS MAKE AND TYPE B 1981 C 1982 D 19 8 3 E 19 84 F 19 8 5 G 19 8 6 H 19 8 7 IN C O M P L E T E V E H IC L E 1 19 8 8 TRUCK K 19 8 9 L 10 9 0 BUS (V A N ) M U L T IP U R P O S E PA SS V E H IC L E M ASSEM BLY PLAN T CODE ASSEM BLY PLANT A G M A D - LAKEW O O D S G M A D - ST B G M A D - B A L T IM O R E V G M T & C -- P O N T IA C D G M A D - D O R A V IL L E Z G M A D - FREM ONT * 1 GM OF C A N A D A - O SHAW A F ' C H E V R O L E T - F L IN T L O U IS J G M A D - J A N E S V IL L E 3 C H E V R O L E T - D E T R O IT K G M A D - LE ED S ' 4 GM OF C A N A D A - SCAR B O R O U G H G M A D - A R L IN G T O N ' 7 G M A D - LO R D S TO W N R • E L C A M IN O P L A N T S 1991 GVWR/BRAKE SYSTEM CHECK D IG lT ] GVW R CODE ( IN P O U N D S ) 3001 4001 5001 6001 7001 8001 9001 10001 14001 B •c D E F ■G H J K 4000 5000 6000 7000 8000 9000 10000 14000 16000 BR A K E SYSTEM ENGINE TYPE AND MAKE TYPE CODE TRUCK SERIES H Y D R A U L IC O N L Y D IS P L A C E M E N T L IT R E S (C U IN ) D 4.1 L L 6 2 B B L (2 5 0 ) C H EVROLET F R PO LE 3 5 .0 L V 8 4 B B L (3 0 5 I CHEVROLET C -K -G LF3 C -K -G LG 9 5 .0 L V 8 2 B B L (3 0 5 ) 1 1 12 T O N H 5 .0 L V 8 4 B B L (3 0 5 ) CHEVROLET C -K -G LE 9 2 3 /4 T O N L 5 . 7 L V 8 4 B B L (3 5 0 ) C H EVROLET C -K -G LS 9 3 1 TO N CHEVRO LET 8 M 5 .7 L V 8 4 B B L (3 5 0 ) 1 12 T O N P 5 .7 L V 8 2 B B L (3 5 0 I C HEVROLET CK LF5 ( E L C A M IN O ) W 7 .4 L V 8 4 B B L (4 5 4 ) C HEVROLET C -K -P LE 8 T 4 . 8 L L 6 1 B B L (2 9 2 ) C HEVROLET C -K -P L25 Z 5 .7 L V 8 D IE S E L (3 5 0 I O L D S M O B IL E CK LF9 TRUCK BODY TYPE 1 H I C U B E /C U T A W A Y V A N 2 FORW ARD CONTRO L C H A S S IS 3 FO U R DOOR CAB TYPE 4 TW O D O O R C AB C -K -G -P LT9 (F O R E L C A M IN O O N L Y ) S E D A N P IC K U P LINE AND CHASSIS TYPE M O D ELS G G In c lu d e s G V a n Bus. L IN E M O D ELS CHEVROLET In c lu d e s El C a m in o CODE M A K E (G M ) E N G IN E S O U R C E V I . N. CODE A TYPE D IS P L A C E M E N T L IT R E S (C U IN ) M A K E (G M ) E N G IN E S O U R C E 3 . 8 L V 6 2 B B L (2 3 1 ) B U IC K M ODEL RPO E L C A M IN O LD 5 H 5 . 0 L V 8 4 B B L (3 0 5 ) C H EVROLET E L C A M IN O LG 4 C C O N V E N T IO N A L C A B (C l 4X 2 5 VAN J 4 4 L V 8 2 B B L (2 6 7 ) C H EVROLET E L C A M IN O L39 K C O N V E N T IO N A L C A B (K ) 4X 4 6 SUBURBAN K 3 . 8 L V 6 2 B B L (2 2 9 ) CHEVR O LET E L C A M IN O LC 3 P F O R W A R D C O N T R O L C H A S S IS (P) 4 X 2 7 M O TO R HOME G V A N . SPORT V A N & C U T A W A Y V A N (G ) 4X 2 8 BLAZER W E L C A M IN O (A P U ) 4X 2 S T A K E /P L A T F O R M Fig. 0A-3--Vehicle Identification Number LIG H T T R U C K SE RV IC E M A N U A L GENERAL INFORMATION SERVICE PARTS IDENTIFICATION STICKER The Service P arts Identification Sticker (Fig. OA-6) is provided on all Truck models. On C and K models, the identification sticker be located on the inside of the glove box door or on G model, the sticker will be located on an inner hood panel surface. On P models, the sticker is located on a inner body panel. T he p late lists the vehicle identification num ber, wheelbase, and all Production options or Special Equipm ent on the vehicle w hen it was shipped from the factory including paint inform ation. ALWAYS REFER TO THIS INFORMATION W HEN ORDERING PARTS. VEHICLE LOADING Vehicle loading m ust be controlled so weights do not exceed the num bers shown on the Vehicle Identification N um ber an d /o r R ating Plate for the vehicle. A typical example of a truck in a loaded condition is shown in Figure OA-7. N ote th a t the axle or G V W capabili­ ties are not exceeded. ENGINE CODE NUMBER T he engine code n um ber indicates m an u factu rin g plant, m onth and day of m anufacture, and transmission type. A typical engine num ber would be F1210TTBB, which would breakdown thus: F - M anufacturing P lant (F-Flint, T -Tonaw anda) 12 - M onth of M anufacture (D ecem ber) 10 - Day of M anufacture (tenth) T - Truck TBB - Transm ission and engine type OA-3 Axles Chevrolet Built • On 10 Series, the Code is stam ped on Top of Right R ear Axle Tube. • On 20-30 Series, the Code is stam ped on Top of the Right R ear Axle Tube. Dana Built • On Front Axles, code is stam ped on Top R ear of Left Axle Tube. • On R ear Axles, code is stam ped on R ear Surface of Right Axle Tube. Transmissions (Fig. OA-6) • On 3-Speed Transm issions (except Trem ec), the U nit N um ber is located on Lower Left Side of Case Just Below Cover. • On Trem ec Transmissions, Unit N um ber is located on Upper Left A ttachm ent Case (Top Side). • On M uncie 4-Speeds, U nit N um ber is located on R ear Face of Case below Retainer. • On New Process 205 model 4-wheel drive transfer case, a build date is on tag attached to front face of transfer case. • On A u to m atic 350 T ransm ission, U nit N u m b er is Located on R ight R ear Vertical Surface of Oil Pan. • On the A utom atic 400 Transmission, Serial N um ber is Located on the Light Blue Plate on the R ight Side of the Transmission. UNIT AND SERIAL NUMBER LOCATIONS For the convenience of service technicians and engi­ neers when w riting up certain business papers such as W arran ty Reports, Product Inform ation Reports, or report­ ing product failures in any way, the location of the various unit num bers have been indicated. These unit num bers and th e ir prefix or suffix are necessary on these papers for various reasons - such as accounting, follow-up on produc­ tion, etc. LO AD ED -M AXIM UM GVWR: FRONT GAWR: 2944 LBS. 4900-LBS. REAR GAWR: 2944 LBS. The prefixes on certain units identify the plant in which the unit was m anufactured and thereby perm its proper follow-up of the plant involved to get corrections made when necessary. Always include the prefix in the num ber. 2219 lbs. * Front Curb Front Cargo & 284 lbs. Pass. Load 2503 lbs. *Rear Curb 1003 lbs. Rear Cargo & Pass. Load 1394 lbs. 2397 lbs. TOTAL W EIGHT AT G RO UND : 4900 lbs. *Curb weight equals the weight of the vehicle without driver, passenger or cargo, but including fuel and coolant. Fig. 0A-4--Service Parts Identification Plate Fig. 0A-5--Typical Vehicle Loading Condition LIG H T T R U C K SERVICE M A N U A L OA-4 GENERAL INFORMATION PRIMARY V .I.N . LOCATION ( M l 5) SECONDARY V .I.N . LOCATION To be used only when .suitable for stamping PRIMARY V .I.N . f \ LOCATION (MV4 or M38) SECONDARY V .I.N . LOCATION To be used only when primary locationis not suitable for stamping PRIMARY V .I.N . LOCATION (M C I) OPTIONAL V .I.N . LOCATION (M20) V .I.N . LOCATION (OPTIONAL) (M40) V .I.N . LOCATION (M20) V .I.N . LOCATION (OPTIONAL) (M40) V IE W MANUAL AUTOMATIC Fig. 0A-6--Transmission V.I.N . Location Engines (Fig. 0A>7) • 6-Cylinder Engine U nit N um ber Located on Pad at R ig h t H and Side o f C ylinder Block a t R ear of D istributor. • 8-Cylinder Gasoline Engine Code is (305, 350, 400 C ID ) Located on Pad im m ediately forward of right hand cylinder head. • 8-Cylinder Gasoline Engine (454 C ID ) Code is located on a pad of the front top center of the engine block im m ediately forward of the inlet manifold. • 8-Cylinder Diesel Engine Code is on a label located on rear face of the left valve cover. LIG H T T R U C K SE RV IC E M A N U A L Generators G enerator U nit Serial N um ber is located on the Drive End Fram e Below the P art N um ber. Batteries Battery Code N um ber is Located on Cell Cover Top of Battery. Starters S ta rte r S erial N u m b er and Production D ate are Stam ped on O uter Case, Toward Rear. GENERAL INFORMATION E N G IN E V .I.N . E N G IN E V .I.N . # OA-5 E N G IN E CASE PAD (O PTIO NAL) E N G IN E V .I.N . DISTRIBUTOR PAD ENGINE L6 ENGINE E N G IN E V .I.N . (OPTIO NAL) V8 ENGINE — DIESEL Fig. 0A-7-Engine V .I.N . Location LIG H T T R U C K SERVICE M A N U A L MAINTENANCE AND LUBRICATION OB-1 SECTION OB MAINTENANCE AND LUBRICATION CONTENTS M aintenance S c h e d u le .................................................................................. Lubrication and G eneral M aintenance.................................................... Safety M aintenance...................................................................................... Emission Control M aintenance............................................................. Specifications.................................................................................................... Recom m ended Fluids and L u b ric a n ts..................................................... Fluid C ap acities............................................................................................. OB-2 0B-5 OB-15 OB-16 0B-18 OB-18 OB-19 LIG H T T R U C K SE RV IC E M A N U A L OB-2 OWNER'S SERVICE LOG (M iles) (km) (Mee*a tt MHw (k>l Wfcklmwr Ocean FW-»t> Item No. 15,000 (24 000 km) 7.500 (12 000 km) Services lns#rt " on,h- 1 •I1<*••• m -v 5/7.500) m column Closest To Mileage (km) When Service Is Performed. 22.500 (36 000 km) 30,000 (48 000 km) 37.500 (60 000 km) 45,000 (72 000 km) S e c t io n A — L u b r ic a t io n a n d G e n e r a l M a in t e n a n c e A -1 Every 12 M onths or 7 ,5 0 0 M iles ( 1 2 0 0 0 km ) Fig. OB-la--Maintenance Schedule, Gasoline, Light Duty Emissions, 49 States See Explanation Every 12 M onths or 1 5 ,0 0 0 M iles ( 2 4 0 0 0 km ) A -2 Every 1 0 0 ,0 0 0 M iles (1 6 0 0 0 0 km ) C lutch Pedal Free Travel Check/Adjust X x j X _Al X X 1 X X X X X X *1 X X X X X A -3 *Engine Oil Change X A -4 ’ E n gin e Oil Filter C h ange X A -5 ‘ Chassis Lubrication A -6 F ront W h eel D rive A -7 Tire Rotation A -8 R ear A x le Lubrication A -9 A -1 0 Every 3 0 ,0 0 0 M iles ( 4 8 0 0 0 km ) ‘ Fluid Levels Check “C ooling System C h eck— See Explanation X X W heel Bearing Repack ■ X X A -1 1 M anual Steering G ear Seals Check X A -1 2 Clutch Cross S haft Lubrication X A -1 3 A uto. Trans. Fluid & Filter Change B-1 O w n er Safety Checks X X X X X X B -2 Tire, W heel and Disc Brake Check X X X X X X X X X X X X Suspension and Steering Check X X X X X X Brake and Power Steering Check X X X X X S e c tio n B — S a f e t y M a in t e n a n c e Every 1 2 M onths or 7 ,5 0 0 M iles ( 1 2 0 0 0 km ) B -3 B -4 B -5 B -6 Every 12 M o nths or 1 5 ,0 0 0 Miles (2 4 0 0 0 km ) ‘ Exhaust System Check *D riv e Belt Check X X X X B -7 Drum Brake and Parking Brake Check X X X B -8 Throttle Linkage Check X X X X X X X X B -9 B-10 Bumper Check •F u e l Cap, Tank and Lines Check X S e c tio n C — E m issio n C o n tro l M a in te n a n c e S c h e d u le 1 (S e e “ E x a m p le ” fo r A p p lic a tio n ) — E n qin e Fam ily 18F 2H A N Q R O nly A t First 6 M onths or 7 ,5 0 0 M iles ( 1 2 0 0 0 k m )—Then at 18 M o n th / 2 2 ,5 0 0 M ile ( 3 6 0 0 0 km ) Intervals as Indicated in Log Every 1 5 ,0 0 0 M iles ( 2 4 ,0 0 0 km ) Every 2 2 ,5 0 0 M iles (3 6 0 0 0 km ) Every 3 0 ,0 0 0 M iles (4 8 0 0 0 km ) C-1 Therm o. Controlled Air Cleaner Check X X X C -2 Carburetor Choke Check X X X C -3 Engine Idle Speed Adjustm ent X X X C -4 EFE System Check X X X C -5 Carburetor M ou n tin g Torque X X X C -6 Vacuum Advance System & Hoses Check X X C -7 Fuel Filter Replacem ent X X X PC V System Check X X X C -8 PC V Valve & Filter Service X X C -9 Spark Plug Wires Check X X C -1 0 Idle Stop Solenoid an d /o r Dashpot Check X X C -11 Spark Plug Replacem ent •x X C-1 2 Engine Tim ing Adjust. & Distrib. Check X X C -13 Air Cleaner Element Replacem ent X C -14 ECS System Check X C -1 5 EG R System Check High Altitude Adiustment: Your 1981 General Motors vehicle has been certified to meet emission standards at low altitude Certain vehicles sold for high altitude use have been adjusted prior to delivery for improved driveability and emission control at high altitude. These vehicles may be identified by additional underhood tune-up label, "Supple- X mental Vehicle Emission Control Information.” Information regarding adjustment of your vehicle, if permitted, can be obtained from the Consumer Relations Office shown in the Owner Assistance Section of your Owner's and Driver's Manual. Include your Vehicle Identification Number in your request. MAINTENANCE AND LUBRICATION VEHICLE MAINTENANCE SCHEDULE VEHICLE MAINTENANCE SCHEDULE OWNER'S SERVICE LOG ( M i l . , I ( M When To Ptrform Services Item No. (M l.— •> MHm (kali WMrtmr Occm n Rfst) 30.000 (48 000 km) 22,500 (36 000 km) 15,000 (24 000 km) 7,500 (12 000 km) Services 37,500 (60 000 km) 45.000 (72 000 km) S e c t i o n A —L u b r ic a t io n a n d G e n t r a l M a in te n ance A-1 Every 1 2 M o n th s or 7 ,5 0 0 M iles ‘ Fluid Levels Check C lutch Pedal Free Travel Check/Adjust A -2 Every 1 2 M o n th s or 1 5 ,0 0 0 M iles ( 2 4 0 0 0 km ) A -3 *Engine Oil Change X A -4 * 0 i l Filter Change X A -5 ‘ Chassis Lubrication A -6 F ront W h eel D rive A -7 Tire Rotation A -8 R ear A x le Lubrication A -9 Every 1 0 0 .0 0 0 M iles (1 6 0 0 0 0 km ) X ' X J L L ......... X X1 X X X X X * x X X X X . .. X X •C o o lin g System C h eck— See Explanation A -1 0 Every 3 0 ,0 0 0 M iles (4 8 0 0 0 km ) X | W heel Bearing Repack X A -1 1 M anual Steering G ear Seals Check X A -1 2 Clutch Cross S haft Lubrication X A -1 3 A uto. Trans. Fluid & Filter Change < S e c t i o n B — S a f e t y M a in t e n e n c e Every 1 2 M o n th s or 7 ,5 0 0 M iles ( 1 2 0 0 0 km ) B-1 O w n er Safety Checks X X X X X X B -2 Tire, W heel and Disc Brake Check X X X X X X X X X X X X Suspension and Steering Check X X X X X X Brake and Power Steering Check X X X X X X B -3 B -4 B -5 B -6 Every 1 2 M o n th s or 1 5 ,0 0 0 M iles w U km j ‘ Exhaust System Check X •D riv e B elt C h eck (2) B -7 Drum Brake and Parking Brake Check X X X B 8 Throttle Linkage Check X X X X X X X X B -9 B-10 Bumper Check *F u e l Cap, Tank and Lines Check X Se ction C — Em ission Control Maintenance Schedule I A t firs t 6 M o n th s o r 7,5 0 0 M iles (12 0 0 0 km ) — T h e n 2 4 -M o n th / 3 0 ,0 0 0 -M ile (48 000 km ) Intervals as in d icate d in Log, Except C-2 a n d C-6, W h ich R e q u ire Service at 4 5 ,0 0 0 M ile s (72 000 km ) Therm o. Controlled Air Cleaner Check C -2 C a rb u reto r Choke & Hoses Check X C -3 Engine Idle Speed A djustm ent X C -4 EFE System Check X C -5 Carburetor M ou n tin g Torque X C -6 Vacuum Advance System & Hoses Check C -7 E v ery 15,000 M ile s (24 000 km ) E v e ry 3 0 ,000 M ile s (48 000 km ) * ▲Also A Safety Service X C-1 X X ---------- PCV System Check X xP X Spark Plug W ires Check C -9 Idle Stop Solenoid an d /o r Dashpot Check C -1 0 Spark Plug Replacem ent C -11 Engine Tim ing Adjust & Distrib. Check X C -1 2 Air C le a n e r & PC V R e p la cem en t E G R System Check X *AI»o An Emission Control Service xT X X PC V Valve R e p la cem en t Hioh Altitude Adjustment: Your 1961 General Motors vehicle has been certified to meet emission standards at low altitude. Certain vehicles sold for high altitude use have been adjusted prior to delivery for improved driveability and emission control at high altitude. These vehicles may be identified by additional underhood tune-up label, "Supple­ mental Vehicle Emission Control Information." Information regarding adjustment of your vehicle, if permitted, can be obtained from the Consumer Relations Office shown in the Owner Assistance Section of your Owner's and Driver's Manual. Indud* your Vehicle MentMcation Number in your request. xt; X (1) C -8 C -1 3 (1) X (1) ---- X X (1) (1) X (1) Only these emission control maintenance items are considered to be required maintenance as defined by the California Air Resources Board (ARB) regulation and are, according to such regulation, the minimum maintenance an owner in California must perform to fulfill the minimum requirements of the emission warranty. All other emission maintenance items are recommended maintenance as defined by such regulation. General Motors urges that all emission control maintenance items be performed. (2) A separately driven air pump belt check is recommended but not required at 15,000 miles (24 000 km) and 45,000 miles (72 000 km). MAINTENANCE AND LUBRICATION Fig. OB-1 b--Maintenance Schedule, Gasoline, Light Duty Emissions, California S e e Explanation X X OB-3 OB-4 V-8 DIESEL FUELED ENGINE S E C T IO N A — «*_ 48,000 15,000 : 000 km) 1200 km) (2,000 19,000 ! 400 km) 13,000 ! 800 km) to m m CO 7.000 1200 km) ° . § n CM — § 1 (48 000 km) at u lc‘*' ■"*?Is5/Performed d '5°0> '!! ColumnMrTth' Closest.D?V' To Mileage When Service M.OOO 1600 km) o o °-s 18,000 1800 km) E o 15,000 1000 km) 12,000 1200 km) Fig. 0B-2--Maintenance Schedule-Gasoline - Heavy Duty Emissions 600 km) Services (For D e ta ils , See Numbered Paragraphs) 6,000 Item No. 3,000 When To Perforin Services M a r t a m H H m /km . W W c k o m O ccan F t a ) 800 km) OWNER'S SERVICE LOG (Miles/km) MAINTENANCE AND LUBRICATION VEHICLE MAINTENANCE SCHEDULE MAINTENANCE AND LUBRICATION OB-5 VEHICLE MAINTENANCE SCHEDULE Insert Montk. Day and Mileage (i.e. M ay 5 /8 ,9 0 0 ) la Colamn Closest te Mileage When Service ia Performed. OWNER'S SERVICE LOG (Miles/km) To Perform Services (Manilaor Milm/km. MThiclMiwr OccanFiratl W han Item No. Services (Far Details. Saa NumbaradParagraphs) 6.000 12.000 (9 600 km) <19 200 km) I t . 000 (21 100 km) 30 000 ( U 000 km) 24.000 (31 400 km) 30.000 <57 OM km) 42 000 ( (7 200 km ) 41 0 M (70 I N km) S e c t io n A — L u b r ic a t io n a n d G e n e r a l M a in t e n a n c e Every 4 m o n th s o r 6 ,0 0 0 m ile s (9 6 0 0 k m ) A -1 •C h a s s is L u b ric a tio n X X X X X X X X A -2 • F lu id L e vels C he c k X X X X X X X X X X X X X X X X X X X X A -5 ‘ E n g in e O il C h a n g e X X X X X X X X A -6 *E n g in e O il F ilte r C h a n g e X A -3 A -4 See E x p la n a tio n X F ro n t W h e e l D riv e C lu tc h P e d a l F ree T ra v e l C h e c k /A d ju s t A -7 T ire R o ta tio n A 8 R ea r A x le L u b r ic a tio n X X X X X X A -9 W h e e l B e a rin g s R ep ack X X X X A -1 0 C o o lin g S ystem C he c k X X X X Every 2 4 ,0 0 0 m ile s ( 3 8 4 0 0 k m ) A -1 1 A u to . T rans. F lu id & F ilte r C ha ng e Eve ry 3 6 ,0 0 0 m ile s (5 7 6 0 0 k m ) A -1 2 M a n u a l S te e rin g G e ar C he c k X A -1 3 C lu tc h C ro ss S h a ft L u b ric a tio n X B-1 O w n e r S a fe ty C h e cks X X X X X X X X B -2 T ire . W h e e l a n d D is c B rake C he c k (1) X X X X X X X X (1 9 2 0 0 k m ) S e c t io n Every 4 m o n th s o r 6 ,0 0 0 m ile s (9 6 0 0 km ) B -3 B -4 B 5 X X B—S a f e t y M a in t e n a n c e X X X X X X X X S u s p e n s io n a n d S te e rin g C he c k X X X X X X X X Brake s an d P o w e r S te e rin g C he c k X X X X X X X X • E x h a u s t S ystem C he c k X Eve ry 1 2 ,0 0 0 m ile s ( 1 9 2 0 0 k m ) B -6 X X X Every 1 2 m o n th s o r 1 2 ,0 0 0 m ile s (1 9 2 0 0 k m ) B -7 D ru m B rake s a n d P a rk in g B rake C he c k X X X X B -8 T h ro ttle L in k a g e C he c k X X X X B -9 B u m p e rs X X X X E v e ry 2 4 m o n th s o r 24 ,0 0 0 m ile s (38 40 0 k m ) B -10 *E n g in e D riv e B e lts C he c k •F u e l C ap , L in e s a n d T a n k C he ck X X S e c t io n C — E m is s io n C o n t r o l M a in t e n a n c e A t 1s t 4 m o n th s o r 6 ,0 0 0 m ile s ( 9 6 0 0 k m ) — th e n a t 1 2 m o n th / 12 ,0 00 m il e (19 2 0 0 k m )in te r v a ls C -1 E n g in e Id le S p ee d A d ju s tm e n t X X X X X C -2 Id le S to p S o le n o id C he c k X X X X X E very 1 2 ,0 0 0 m ile s (1 9 2 0 0 k m ) C -3 S p ark P lu g W ire C h e c k & P lu g R e p la c e m e n t X X X X C -4 * E n g in e T im in g A d ju s t. & D is trib u to r C h e ck X X X X C -5 • A ir C lea ne r E le m e nt R ep lac e m e nt X X X X X X X X Every 12 m o n th s o r 1 2 ,0 0 0 m ile s (1 9 20 0 km ) C -6 C a rb u re to r M o u n tin g T o rq u e C -7 •T h e r m o . C o n tro lle d A ir C lea ne r C h e c k X X X X C -8 • M a n if o ld H ea t V a lv e C he c k X X X X C -9 C a rb u re to r F ue l F ilte r R e p la c e m e n t X X X X C -1 0 T h ro ttle R e tu rn C o n tro l C h e c k X X X X C -1 1 PC V S y s te m C h e c k X X X X — PC V V a lv e & F ilter S e rvice E very 2 4 m o n th s or 2 4 ,0 0 0 m ile s ( 3 8 4 0 0 k m ) •A ls o A S a fe ty S e rvice X X C -1 2 ECS S ystem C he ck X X C -13 E n gin e Id le M ix tu r e A d ju s t (4 .8 L. L - 6 o n ly ) X X C -14 EFE System C he c k X X C -1 5 V a c u u m A d v a n c e S ystem C he ck X X C -1 6 C a rb u re to r C h o k e C he ck X X *A ls o A n E m is s ion C o n tro l S e rv ic e * A ls o a N o is e E m is s io n C o n tr o l S e rv ic e (1) F o r v e h ic le s w ith d u a l w h e e ls , r e fe r to te x t B -2 f o r e a r lie r m a in te n a n c e . Fig. 0B-3--Maintenance Schedule - Diesel MAINTENANCE SCHEDULE T his is an explanation o f th e service listed in the Vehicle M aintenance Schedule. N O R M A L V E H IC L E U S E -T h e m ain ten an ce in ­ structions contained in the m aintenance schedule are based on the assum ption th a t the vehicle will be used as designed: • To carry passengers and cargo within the lim itations indicated on the T ire Placard located on the edge of the driver’s door, • on reasonable road su rfaces w ithin legal o perating limits, • on a daily basis, as a general rule, for at least several miles (km ), and • O n unleaded gasoline (gasoline light duty emission only). SECTION A LUBE & GENERAL MAINTENANCE A -l Fluid Levels Check battery and the following fluid levels: Battery Care The original equipm ent battery (two batteries on diesel engine) needs no periodic m aintenance. Its top is perm a­ nently sealed (except for two small vent holes) and has no filler caps. W ater will never have to be added. The h y drom eter (te st indicator) in the top of the battery provides inform ation for testing purposes only. See Section 6D for battery test procedures. U nusual operating conditions will require more fre­ quent vehicle m aintenance as specified in the respective sections. LIG H T T R U C K SERVICE M A N U A L OB-6 MAINTENANCE AND LUBRICATION Jump Starting CAUTION:Batteries produce explosive gases, cor­ rosive acid and levels of electrical current high enough to cause burns. To lessen the chance of personal injury or property damage, the instruc­ tions below must be followed exactly. • Always wear eye protection or shield your eyes when working near any battery. Do not lean over a battery. Remove all m etal jewelry. • N ever expose a b a tte ry to open flames or electric sparks. Also, do not smoke near a battery. • Do not allow b attery acid to contact eyes, skin, fabrics or painted surfaces. F L U S H A N Y C O N T A C T E D A R E A W IT H W A T E R IM M E D IA T E L Y A N D T H O R O U G H L Y . G E T M E D IC A L H E L P IF EY ES ARE A FFECTED . • Be sure the ju m p er cables or clam ps to be used for jum p starting do not have loose or missing insulation. Do not proceed if suitable cables are not available. • T his vehicle has a 12-volt b a tte ry and a negative ground electrical system. M ake sure th at the other vehicle also has a 12-volt b attery and th at it is the negative (black te rm in a l w hich is grounded (attached to the engine block). Its ow ner’s m anual may give you th a t inform ation. Do not try to jum p start if you are unsure of the other vehicle’s voltage or ground (or if the other vehicle’s voltage an d /o r ground are different from your vehicle). • If either battery has filler caps, check the fluid level. (Do not check with an open flame.) If low, fill to the proper level with clear drinking w ater. Replace all caps before jum p starting. • Do not allow m etal tools to contact both the positive (red " + ") b attery term inal (or any m etal connected to this term inal) and any other m etal on either vehicle at th e sam e tim e. M ake certain when a tta c h in g the jum per cable clam ps to the positive .term inals of the batteries th at neither clam p contacts any other m etal. • Always make the final connection to ground (a solid, stationary, m etallic object) on the engine at least 450 m illim eters (18 inches) from the battery. fluid. See section on power steering system when checking fluid level or adding fluid. NOTICE: Power steering fluid and brake fluid cannot be mixed, since seat dam age may result. Power Steering System (Also a Safety Service) Check the fluid level in the power steering pum p at each oil change and add G M Power Steering FLuid (G M 1050017) or equivalent as needed (Fig. OB-4): • If fluid is w arm ed up (about 150°F or 6 6 °C -h o t to the touch), it should be between " H o t" and "C old" marks on the filler cap indcator. • If cool (about 70°F or 21°C), fluid should be between "A d d " and "C old" marks. Fluid does not need periodic changing. Rear Axle (Standard) Lubricant Check lubricant level. Add lubricant, if necessary, to fill to level of filler plug hole. Use SA E 80W GL-5 or SA E 80W -90 GL-5 or G M 1052271 /1052272 gear lubricant. For those vehicles driven in C anada, use SA E 80W GL-5 gear lubricant. Rear Axle (Limited-Slip) Lubricant Check lubricant level. Add lubricant, if necessary, to fill to level of filler plug hole. Use gear lubricant GM 1052271/1052272 or equivalent. Automatic Transmission Fluid Use only auto m atic transm ission fluid labeled D E X R O N ® -II or equivalent. Check the autom atic transmission fluid level at each engine oil change period. Overfilling can cause foaming and loss of fluid. Transmission dam age can result. Low fluid level can cause slipping or loss of drive. A utom atic transmissions are often overfilled because the fluid level is checked when the fluid is cold. W hen cold, the dipstick shows th at fluid should be added. However, the Brake Master Cylinder (Also a Safety Service) Check fluid level in each reservoir and m aintain 1/4" below lowest edge of each filler opening with Delco Suprem e No. 11 or DOT-3 hydraulic brake fluid, or equivalent. A low fluid level in the brake m aster cylinder can indicate worn disc b rak e pads, and should be checked accordingly. Hydro-boost Brake System Hydraulic Pump 1. Vehicles Equipped W ith Power Steering. • On vehicles equipped with power steering, the power steering pump is also used as the Hydro-boost pump. See section on power steering system when checking fluid level or adding fluid. 2. Vehicles Equipped W ith M anual Steering. • T he H ydro-boost pum p installed in vehicles equipped with m anual steering uses power steering L IG H T T R U C K SE RV IC E M A N U A L Fig. 0B-4--Power Steering Filler Cap MAINTENANCE AND LUBRICATION OB-7 low reading is normal, the level will rise as the fluid gets warm. The fluid level will increase more than 3/4 inch (19m m ) as fluid warm s up from 60°F to 180°F (16°C to 82°C). • Use a fluid such as G M Optikleen or equivalent to help prevent freezing dam age, and for better cleaning. C heck th e transm ission fluid level w ith the engine running, the shift lever in " P a r k ", and the vehicle level. • In cold weather, warm the windshield with the defrosters before using the washer--to help prevent icing that may block the driver’s vision. If the vehicle has ju st been driven for a long tim e at high speed or in city traffic in hot w eather, or if the vehicle has been pulling a trailer, the correct fluid level cannot be read. W a it until th e fluid has cooled down (ab o u t 30 m inutes). Remove the dipstick. C arefully touch the wet end of the dipstick to find out if the fluid is cool, w arm or hot. W ipe it clean and push it back in until cap seats. Pull out the dipstick and read the fluid level (fig. OB-5). • If it felt cool, about room tem perature, the level should be 1/8 to 3/8 inch (3 to 10mm) below the "A d d " m ark. The dipstick has two dim ples below the "A d d " m ark to show this range. • If it felt warm , the level should be close to the "A d d " m ark (either above or below). • If it was too hot to hold, the level should be at the "F u ll" m ark. • It takes only one pint (0.5 liter) to raise level from "A d d " to "F u ll" with a hot transm ission. M anual Transmission Lubricant C heck lubricant level. A dd lubricant, if necessary, to fill to level of filler plug hole. U se SA E 80W G L-5 or S A E 80W -90 G L-5 gear lubricant. For those vehicles driven in C anada, use SA E 80W G L-5 gear lubricant. • Do not use ra d ia to r an tifreeze in the w indshield washer; it could cause paint dam age. Cooling System Care Do not remove radiator cap to check coolant level. Instead, check by looking at the "see through" coolant recovery tank. Level should be at the "F ull C old" m ark or the recovery tank when the system is cold; and at the "Full H ot" m ark during engine operation. Add a 50/50 mixture of a good quality ethylene glycol antifreeze and w ater to the recovery tank when more coolant is needed. If frequent additions are needed, cooling system. NOTICE: If the proper quality antifreeze is used, there is no need to add extra inhibitors or additives th at claim to improve the system. They may be harm ful to the proper operation of the system, and are an unnecessary expense. A-2 Manual Transmission Clutch Adjustment C lutch adjustm ent should be checked and adjusted as necessary to com pensate for clutch facing wear. To check, depress pedal by hand until resistance is felt. Free travel should be approxim ately one to one and a half inches; if very little or no free travel is evident, clutch a d ju stm en t is required. A-3 and A-4 Engine Oil and Filter (Also an Emission Control Service) Engine Oil and Filter Recommendations Windshield Washer Fluid (Also a Safety Service) Fill the w asher ja r only 3 /4 full during the w inter to allow for expansion if th e te m p e ra tu re should fall low enough to freeze the solution. • C heck the w asher fluid level re g u la rly -d o it often when the w eather is bad. Gasoline Engine • Engine oils are labeled on the containers with various A PI (A m erican Petroleum Institute) designations of quality. • Use only S F q u ality engine oils (see m arkings on containers). • The oil and filter change intervals for the engine is based on the use of SF-quality oils and high quality filters. Using oils other than SF-quality oils, or oil change intervals longer than listed, could reduce engine life and m ight affect w arranty. • The engine was filled with an S F quality engine oil when it was built. You do not have to change this oil before the suggested change period. • Change oil each 7,500 miles (12 000 km) or once a year for light duty emissions service, each 6,000 miles (9 600 km) or 4 m onths for heavy duty emissions service, whichever occurs first. LIG H T T R U C K SE RV IC E M A N U A L OB-8 MAINTENANCE AND LUBRICATION • Change oil filter: Light Duty Emissions- Replace at the first oil change and then every second oil change if mileage 7,500 miles (12 000 km) determines oil change. If time (12 months) determines oil change, or you change the oil at 3,000 miles (4 800 km) or 3 months, replace filter at each oil change. Heavy Duty Em issions- Replace at the first oil change, and then every second oil change if mileage 6,000 miles (9 600 km) determines oil change. If tim e (4 m onths) determines oil change, or you change the oil at 3,000 miles (4 800 km) or 2 months, replace filter at each oil change. • Change oil and filter each 3,000 miles (4 800 km) or 3 months (light duty emissions) or 2 months (heavy duty emission service) if: • Driving in dusty areas • Pulling a trailer • Frequent idling or idling for long periods • Driving 4 miles (6 km) or less in freezing weather, or other short trips in cold weather, where the engine does not thoroughly warm up. • After driving in a dust storm, change the oil and filter as soon as possible. Engine Oil Additives - The engine should not need these extra engine oil helpers or additives if SF quality engine oil is used and changed as suggested. If you think your engine has an oil related problem, refer to Section 6A. can, be sure not to confuse the S E designation with the letters " SA E ", which m ay also appear on the can. • It is V ER Y IM P O R T A N T to change the oil and filter every 3,000 miles (4 800 km ). Because of the way a diesel engine operates, contam inants build up in the oil faster than in a gasoline engine which can cause engine wear an d /o r dam age. • Change the oil and filter soon after driving in a dust storm. • Single viscosity grade oils (such as SA E 30) are more satisfacto ry th an m ulti-viscosity oils (such as SA E 10W -30) for sustained high-speed driving. The oil and filter change intervals for a diesel engine are based on the use of " S F /C C " or " S F /C D " quality oils and quality oil filters. Use of oils other than " S F /C C " or " S F /C D " or oil and filter change intervals longer than 3,000 miles (4 800 km) could reduce engine life and may affect w arranty. The diesel engine was filled with a quality engine oil when it was built. You do not have to change the oil before the recommended change interval. Keep in m ind the engine may use more oil when it is new. Check the oil level more often when the engine is new. Engine Oil Additives - Do not use any supplem ental additives. Using oil additives may cause engine dam age and may affect w arranty. If you think the engine has an oil related problem, see Section 6A. RECOMMENDED SAE VISCOSITY GRADES Diesel Engine Use O N LY engine oils labeled with the A.P.I. (Ameri­ can Petroleum Institute) designations "SF/C C " or "SF/ CD ". Do not use any other type of oil. The A.P.I. designa­ tions are listed somewhere on the oil can, usually on the top or label. The A.P.I. has several designations, such as: SC, SD , SE, CB, CC, CD. Several different designations may appear on the can. Be sure the oil used has either the "SF/C C " or "SF/CD" designations, regardless of the order in which they appear on the oil can. Using any type of oil other than "SF/C C " or "SF/ CD" may affect warranty. NOTICE: Do N O T use engine oils labeled only SE or only CC. These oils will not give the protection and lubrication of diesel engine needs. When reading the LIG H T T R U C K SE RV IC E M A N U A L 5W-20 °C-30 --- r— -2 0 20_ -1 0 40 _L_ —I— 10 —r~ 100 T 40 30 TEMPERATURE RANGE ANTICIPATED BEFORE NEXT OIL CHANGE .20 NOTICE: Do not use SAE 5W -20 oils for continuous high-speed driving. Fig. OB-6--Oil Viscosity Chart (Gasoline) MAINTENANCE AND LUBRICATION Oil Viscosity (Figs. OB-6 and 7) Engine oil viscosity (thickness) has an effect on fuel economy. Lower viscosity engine oils can provide increased fuel economy; however, higher tem perature w eather condi­ tions require higher viscosity engine oils for satisfactory lub ricatio n . Figures OB-6 and OB-7 lists the engine oil viscosities th a t will provide the best balance of fuel econ­ omy, engine life, and oil economy. Checking Oil Level • Warm- The best tim e to check the engine oil level is when the oil is warm , such as during a fuel stop. First, allow about 5 m inutes for the oil to drain back to the oil pan. Then pull the dipstick out, wipe it clean, and push it back down all the way. Now pull the dipstick out and look a t the oil level on the dipstick. Some dipsticks are m ark ed w ith " A d d " and " F u ll" lines. O th ers are m arked "A dd 1 Q t" and "O perating R an g e". In all cases, keep the oil level above the "A dd" line. Push the dipstick back down all the way after taking the reading. A dd oil if needed. • Cold- If you check the oil level when the oil is cold, do not run the engine first. T he cold oil will not drain back to the pan fast enough to give a tru e oil level. a. On C20, G 30 and P20, lubricate every 4 m onths or 6,000 miles (9 600 km). b. On all other vehicles, lubricate every 12 m onths or 7,500 miles (12 000 km). M aintain correct front end alignm ent to provide easy steering, longer tire life, and driving stability. Check control arm bushings and ball joints for wear. L ubricate tie rods, upper and lower control arm s, and ball jo in ts a t fittings w ith w ater resistan t E P chassis lubricant which m eets G eneral M otors Specification G M 6 0 3 1M. L ubricate every 3 m onths (Light D uty), 2 months (H eavy D uty and D iesel), or 3,000 miles (4 800 km) whichever occurs first, under the following conditions: • Driving in dusty or m uddy conditions. • Extensive off-road use. Ball joints m ust be at 10°F (-12°C) or more before lubricating. USE THESE SAE VISCOSITY GRADES I A-5 Chassis Lubrication (Figs. OB-8 and 9) Large fluid loss in any of these units m ay point out a problem. R epair these problems prom ptly. Steering Linkage and Suspension SAE 30 WSAE 10W-30 °F -20 I L ubricate the following system or units: OB-9 C -30 0 20 i i-----------1— -20 -10 I 32 40 '----------(— 0 60 ■-------- 1-------- 1— 10 80 i--------- 1— 20 100 i--------- L——i--------- 30 40 •FOR SUSTAINED HIGH SPEED DRIVING ABOVE 32°F (O't) USE SAE 30 GRADE. TEMPERATURE RANGE YOU EXPECT BEFORE NEXT OIL CHANGE (Also a Safety Service) L ubrication Intervals Fig. OB-7--ON Viscosity Chart (Diesel) LIG H T T R U C K SERVICE M A N U A L OB-10 MAINTENANCE AND LUBRICATION 5 Lower C ontrol Arms Upper C ontrol Arms Upper and Lower Control Arm Ball Joints Intermediate Steering Shaft (PA10) Tie Rod Ends 1 2 3 4 5 A ir Cleaner C ontrol Linkage Points Tie Rod Ends Wheel Bearings Steering Gear 1 2 3 4 6 7 8 9 10 Wheel Bearings Steering Gear A ir Cleaner - Element Master C ylinder Transmission - Manual - A utom atic 11 12 13 14 15 T h ro ttle Bell Crank - L-6 Carburetor Linkage - V-8 Brake and Clutch Pedal Springs Universal Joints Rear Axle LUBRICATION POINTS 6 7 8 9 10 Master Cylinder Transmission - Manual - A utom atic Carburetor Linkage - V-8 Universal Joints Propeller Shaft Slip Joints 11 12 13 14 15 Fig. 0B-8--Lubrication Points (Conventional and Four Wheel Drive) LIG H T T R U C K SERVICE M A N U A L Front and Rear Axle Drag L in k Brake and Clutch Pedal Springs Transfer Case T h ro ttle Bell Crank - L-6 MAINTENANCE AND LUBRICATION OB-11 LUBRICATION POINTS 1 2 3 4 Control Arm Bushings and Ball Joints Tie Rod Ends Wheel Bearings Steering Gear Clutch Cross-Shaft 5 6 7 Trans. Control Shaft A ir Cleaner - Element Transmission - Manual - A u to m a tic 8 9 10 11 Rear Axle Oil Filter Brake Master Cylinder Parking Brake Linkage Fig. 0B-9--Lubrication Points (G Van) Transmission Shift Linkage Door Lock Cylinder (Manual and Automatic) Use W D-40 or equivalent spray lubricant as necessary for free operation. (Also a Safety Service) Gas Tank Filler Door Hinge L ubricate shift linkage and m anual transm ission floor controls lever co n tactin g faces w ith w ater resistan t EP chassis lubricant which meets G M specification 6031M. Clean area of d irt and old lubricant. Apply a few drops of engine oil to friction point of door hinge. W ork door several times and wipe off excess lubricant. Hood Latches Door Hinge Assembly Lubricate hood latch assem bly and hood hinge assem ­ bly as follows: W ipe off d irt and apply a thin coat of engine oil. Open and close door several times to insure th at the oil has worked in effectively. 1. W ipe off any accum ulation of dirt or contam ination on latch parts. 2. Apply L ubriplate or equivalent to latch pilot bolts and latch locking plate. 3. Apply light engine oil to all pivot points in release m echanism , as well as prim ary and secondary latch m echanisms. 4. L ubricate hood hinges. 5. M ake hood hinge and latch m echanism functional check to assure the assembly is working correctly. Door Jam Switch Apply a thin coat of lubriplate or equivalent to end of surface of switch plunger. Parking Brake Pulley, Cable and Linkage (Also a Safety Service) Apply w ater resistant EP chassis lubricant which meets G M specification 6 0 3 1M, to parking brake cable at cable guides and at all operating links and levers. LIG H T T R U C K SERVICE M A N U A L OB-12 MAINTENANCE AND LUBRICATION Accelerator Linkage (Also a Safety Service) Lubricate carburetor stud and carburetor lever and accelerator pedal lever at support with engine oil. Body Lubrication See Body Service M anual for body lubrication. A-6 Four Wheel Drive M ost lubrication recom m endations and procedures for four wheel drive-equipped vehicles are the same for corre­ sponding components of conventional drive vehicles. In addition, the following item s require lubrication each 4 m onths or 6,000 miles (9 600 km). Transfer Case Check the transfer case level at the interval and if necessary, add Dexron® II. Front Axle The front axle should be checked at the interval and refilled w ith S A E 80W -90 G L -5 gear lu b ric a n t when necessary. W ith the differential at operating tem perature fill to the level of filler plug hole. If differential is cold, fill to level of 1/2 inch below the filler plug hole. Propeller Shaft Slip Joints Propeller shaft slip joints should be lubricated at the interval with w ater resistant E P Chassis lubricant which m eets G eneral M otors Specification G M 6031M. Constant Velocity (C /V Joint) A C /V joint is located a t the transfer case end of the front propshaft and must be lubricated at the interval with G M lubricated part no. 1052497 or equivalent. See Fig. 0B10 showing how the fitting m ay be lubricated from above the C /V joint, with a special ad ap ter on the end of a flex hose. A-7 Tires Inspection and Rotation Front and rear tires perform different jobs and can wear differently depending on the types of roads driven, driving habits, etc. To obtain m axim um tire life inspect and rotate tires regularly. (Fig. 0 B -11) If the truck is equipped with tires having different load ratings between the front and the rear, the tires should not be rotated front to rear. Vehicle handling could be adversely affected and the tires having the lower load rating could be overloaded. CAUTION:Before installing wheels, remove any build up of corrosion on the wheel mounting surface and brake drum or disc mounting surface by scraping and wire brushing. Installing wheel without good metal-to-m etal contact at the mounting surfaces can cause the wheel nuts to loosen, which can later allow a wheel to come off while the vehicle is moving, possibly causing loss of control. Dual Tire Operation The outer tire of a pair on dual wheel installations generally wears faster than the inner tire, if this occurs, reverse position of the tires to equalize wear and achieve optim um tire life. In addition, when trucks are driven continuously on high crown roads, an increase in air pressure of from 5 psi (35 kPa) to 10 psi (70 kPa) in the outside tire of each dual produces m axim um tire life. Be sure not to exceed the inflation pressure limits shown in the Load and Inflation C harts in Section 3E. Wheel Nut Torque (Fig. OB-12) Caution: Trucks With Single Wheels: As soon as possible after installing a wheel-and at the intervals shown on the chart in the Maintenance Schedule have a mechanic tighten wheel nuts with a torque wrench to the correct torque listed on the chart which follows. Trucks With Dual Wheels: Have a mechanic tighten wheel nuts with a torque wrench as stated above for single wheels for both front and rea r wheels. In addition, when the tru ck , or wheel, or fasteners are new, also have the torque set at the first 100, 1,000, and 6,000 miles (160, 1 600, and 9 600 km ). This precaution is necessary because the clam ping system used on this type of wheel in some cases needs to seat before the fasteners will hold a uniform clam p load and rem ain fully tightened. For both single and dual wheels, wheel nuts should be tightened alternately and evenly to the correct torque in the ROTATION - BIAS AND BIAS • BELTED ROTATION • RAOIAL *Oo not indudo “temporary an only" sparo tiro in rotation. Fig. 0B -10--C /V Joint Lube Fitting L IG H T T R U C K SE R V IC E M A N U A L Fig. 0B-11--Tire Rotation MAINTENANCE AND LUBRICATION sequence shown in Section 3E. N ever use oil or grease on studs or nuts. Im properly tig h ten ed wheel nuts could eventually allow the wheel to come off while the vehicle is moving, possibly causing loss of control. OB-13 Bleeding serves to reduce "cold" inflation pressure and increase tire flexing which can result in tire dam age and failure. Passenger-Car-Type tires: CAUTION:This vehicle has some parts dimen­ sioned in the metric system as well as in the customary system. Some fasteners are metric and are very close in dimension to well-known custom­ ary fasteners in the inch system. Mismatched or incorrect fasteners can result in damage to the vehicle or possibly personal injury. Inflation Pressure (Fig. OB-13) The cold inflation pressures for the factory installed tires are on the label on the rear of the driver’s door. The tires m ust be inflated to these pressures to obtain the G V W R (Gross Vehicle W eight R ating) or G A W R (Gross Axle W eight R ating). Incorrect tire inflation pressures can have adverse effects on tire life and vehicle perform ance. Too low an air pressure causes increased tire flexing and h eat b uild-up. T his w eakens th e tire and increases the chance of dam age or failure and can result in tire overload­ ing, ab n o rm al tire w ear, adverse vehicle handling, and reduced fuel mileage. Too high an air pressure can result in abnorm al wear, harsh ride, and also increase the chance of dam age from road hazards. Lower inflation pressures can be used for light trucktype tires with reduced vehicle loads. A fter finding the load on each tire by weighing the vehicle on a scale, the minimum cold inflation pressures can be found in Section 3E. T ire inflation pressures should be checked at least m onthly (including the spare if so equipped). Always check tire inflation pressures when tires are " cold ". 1. The "co ld " tire inflation pressure applies to the tire pressure when a vehicle has not been driven more than one mile (1.6 km) after sitting for three hours or more. 2. It is norm al for tire pressures to increase 4 to 8 pounds per square inch (30 to 60 kilopascals) or more, when the tires become hot from driving. Do not "bleed" or reduce tire inflation pressures after driving vehicle. TORQUE DESCRIPTION SERIES K10 7/16” BOLTS (6) 70-90 FT. LBS. 95-120 N.m C10, G10, G20 AND P10 1/2” BOLTS (5) 75-100 FT. LBS. 100-140 N.m C20, K20, C30, G30, P20 AND P30 SINGLE WHEELS C30, K30, G30 AND P30 DUAL WHEELS 9/16” BOLTS (8) 9/16” BOLTS (8) HEAVY DUTY WHEELS 5/8” BOLTS (10) For sustained driving at speeds of 75 mph of 85 mph (120 km/h to 140 km/h), in countries where such speeds are permitted by law, cold inflation pressures must be increased 4 psi (30 kPa) above the stated cold inflation pressures on the Certification Label. Sustained speeds of 75 mph to 85 mph (120 km/h to 140 km/h) are not advised when the 4 psi (30 kPa) adjustm ent would require pressures greater than the maxim um pressures stated for each load range. Sus­ tained driving at speeds over 85 mph (140 km/h), where such speeds are permitted by law, is not advised unless vehicle is equipped with special high speed. Truck-Type Tires: ’ For sustained driving at speeds over 65 mph (100 km/h), where such speeds are permitted by law cold inflation pressures should be increased 10 psi (70 kPa) above those stated in the Tire/W heel Load and Inflation Pressure Charts for the load being carried. Do not exceed the wheel capacity limit shown in Section 3E. Sustained speeds over 65 mph (100 km/h) are not advised where the 10 psi (70 kPa) pressure increase would exceed the wheel capacity limit. For special operating conditions, such as carrying slidein cam pers, cold inflation pressures may be increased up to 10 psi (70 kPa) above those shown in the table. The total increase in cold inflation pressures, however, m ust not exceed the wheel capacity limit shown in Section 3E. Passenger-car-type tires have a 15-inch (380 m illim e­ ter) or sm aller wheel size and have no " L T " designation molded in the sidewall after the tire size. Light truck-type tires have " L T " molded in the sidewall after the tire size an d /o r are larger than 15 inches (380m m ) in wheel size. Passenger-Car Type Snow Tires: W hen using passenger-car-type snow tires, cold infla­ tion pressures should be increased 4 psi (30 kPa) above the stated cold inflation pressures on the Certification Label up to the m axim um for each load range stated in the chart above. Sustained speeds above 75 mph (120 km/h) are not advised. CAUTION:Be sure to keep tires properly inflated. A tire that is run while significantly underinflated will overheat to the point where the tire may blow 90-120 FT. LBS. 120-160 N.m 110-140 FT. LBS. 150-190 N.m 130-180 FT. LBS. 175-245 N.m PROPERLY INFLATED BIAS OR BIAS-BELTED TIRE PROPERLY INFLATED IMPROPERLY INFLATED t J -------------- y ___________________________________ RADIAL TIRE Fig. 0B-12--Wheel Nut Torque Fig. 0B-13--Properly Inflated Tire LIG H T T R U C K SERVICE M A N U A L OB-14 MAINTENANCE AND LUBRICATION out and/or catch fire, possibly resulting in dam­ age to the vehicle and its contents and/or per­ sonal injury to its occupants and persons in the area. Truck-Type Snow Tires: W hen using truck-type snow tires, cold inflation pres­ sures should be increased 10 psi (70 kPa) above the advised pressures for the load being carried. However, do not exceed the wheel capacity lim it shown in Section 3E. Sustained speeds above 65 mph (100 km/h) are not advised. 3. For proper inflation pressures when towing trailers, the following is recom mended: W hen towing trailers on dead-w eight hitches, inflate tires to the pressures shown on the C ertification Label (on either the left door latch post or the left door edge next to the driver) or, if applicable the "T ire Inflation Pressure" charts in Section 3E. For trailers using w eight-distributing hitches, increase front tire pressure 2 psi (14 kPa) above the pressure shown on the C ertification Label (or "T ire Inflation Pressure" charts). This increase should never exceed the m axim um pressure shown on the side of the tire. It should be rem em bered th a t when a trailer is con­ nected, the trailer tongue weight is p art of the load being carried by the vehicle and, therefore, is included in the GV W of the vehicle. 4. Always use a tire pressure gage (a pocket-type gage is advised) when checking inflation pressures. A visual inspection of tires for inflation pressures is not enough, especially in the case of radial tires. U nderinflated radial tires m ay look sim ilar to correctly inflated radial tires. If the inflation pressure on a tire quite often is found to be low, correct the cause. 5. Be sure to reinstall th e tire inflation valve caps, if so equipped, to prevent d irt and m oisture from getting into the valve core which could cause air leakage. 6. If an air loss occurs while driving, do not drive on the deflated tire more th an is needed to stop safely. Driving even a short distance on a deflated tire can dam age a tire and wheel beyond repair. A-8 Rear Axle D rain and refill to level of filler plug hole every 7,500 miles (12 000 km ) on light duty emissions or 12,000 miles (19 200 km ) on heavy duty emissions when using vehicle to pull a trailer or severe operating conditions. Use SA E 80W GL-5 or SA E 80W -90 G L-5 gear lubricant. In C anada, use S A E 80W GL-5 gear lubricant. On 20 and 30 series trucks, change lubricant every 24,000 miles (38 400 km). A-9 Cooling System (Also a LD Emission Control Service) The coolant recovery system is standard. The coolant in the radiator expands with heat, and the overflow is collected in the recovery tank. W hen th e system cools down, the coolant is draw n back into the radiator. The cooling system has been filled a t the factory with a quality coolant th at meets G eneral M otors Specification 1899-M. The coolant is a 50/50 m ixture of w ater and ethylene glycol antifreeze. L IG H T T R U C K SE RV IC E M A N U A L Service • M aintain cooling system freeze protection at -34°F (-37°C) to ensure protection against corrosion and loss of coolant from boiling. This should be done even if freezing tem peratures are not expected. • A dd ethylene glycol base coolant th a t m eets G M Specification 1899-M when coolant has to be added because of coolant loss or to provide added protection ag ain st freezing a t tem p era tu res lower th an -34°F (-37°C). • Alcohol or m ethanol base coolants or plain w ater alone should not be used in a vehicle a t any time. T he cooling system should be serviced each year (15,000 miles, 24 000 km, on light duty emission service) (12,000 miles, 19 200 km, on heavy duty emission and diesel engine vehicle service) as follows: 1. W ash radiator cap and filler neck with clean water. 2. Check coolant level and test for freeze protection. 3. T est system and ra d ia to r cap for proper pressure holding capacity, 15 psi (105 kPa). If replacem ent cap is needed, use a cap designed for coolant recovery systems and specified model. 4. Tighten hose clamps and inspect all hoses. Replace hoses if swollen, "checked", or otherwise deteriorated. 5. Clean frontal area of radiator core and air conditioning condenser. Flush and Refill Every two years, 30,000 miles (48 000 km) on light duty emissions or 24,000 miles (38 400 km) on heavy duty emissions and diesel engine vehicles, whichever occurs first, the cooling system should be flushed and refilled as follows: 1. Remove radiator cap when engine is cool: • Turn cap slowly to the left until it reaches a "stop" (Do not press down while turning the cap). • W ait until pressure is relieved (indicated by a hissing sound); then press down on cap and continue to rotate to the left. CAUTION:To help avoid the danger of being burned, do not remove the radiator cap while the engine and radiator are still hot. Scalding fluid and steam can be blown out under pressure if the cap is taken off too soon. 2. W ith radiator cap removed, run the engine until upper radiator hose is hot (this shows th at the therm ostat is open and the coolant is flowing through the system ). 3. Stop engine and open radiator drain valve to drain coolant. (D rainage may be speeded by removing drain plugs in the block.) 4. Close d rain valve (install block d rain plugs, if re ­ moved). Add w ater until system is filled. 5. R epeat steps 3, and 4 several tim es until the drained liquid is nearly colorless. 6. D rain system and then close rad ia to r d ra in valve tightly. (Install block drain plugs, if removed.) 7. Remove recovery tan k cap, leaving hoses in place. Remove coolant recovery tank and em pty fluid. Scrub and clean inside of tank with soap and w ater. Flush well with clean w ater and drain. Reinstall tank. MAINTENANCE AND LUBRICATION 8. A dd enough ethylene glycol solution, m eeting G M Specification 1899-M, and w ater to provide the re­ quired cooling function as well as freezing and corro­ sion p rotection. Use a 50 percen t solution, -34°F (-36°C), but no more than a 70 percent solution. Fill radiator to the base of the radiator filler neck and raise level of coolant in the recovery tank to the "F ull H o t" m ark. Reinstall recovery tank cap. 9. Run engine, with radiator cap removed, until radiator upper hose is hot. 10. W ith engine idling, add coolant to radiator until level reaches bottom of filler neck. Install cap, m aking sure arrows line up with overflow tube. OB-15 gear housing should be refilled only with the proper Steering G ear L ubricant as noted below. NOTICE: Use only 1052182 (13 oz. (.38L) container) Steering G ear L ubricant which meets G M Specifica­ tion 4673M , or its equivalent. Do not use EP chassis lube, m eeting G M Specification 6 0 3 1M, to lubricate the gear. DO N O T O V E R -F IL L the gear housing. A -12 Clutch Cross-Shaft Rem ove the plug, install a lubrication fitting and lubricate with w ater resistant EP Chassis L ubricant which meets G M Specification 6031M. Radiator Pressure Cap A -13 Automatic Transmission Fluid T he rad iato r cap, a 15 psi (105 kPa) pressure type, m ust be installed tightly, otherw ise coolant may be lost and dam age to engine m ay result from overheating. R adiator pressure cap should be checked periodically for proper operation. R efer to A-1 for checking au to m atic transm ission. C hange the transm ission fluid and service screen every 15,000 miles (24 000 km) on light duty emissions or 12,000 miles (19 200 km) on heavy duty emission and diesel engine vehicles if the vehicle has been driven under one or more of these hot conditions: • In heavy city traffic where the outside tem perature regularly reaches 90°F (32°C). • In hill or m ountain areas. • Frequent trailer pulling. • Uses such as taxi, police or delivery service. Thermostat T he engine coolant te m p e ra tu re is controlled by a therm ostat. It stops coolant flow through the radiator until a pre-set tem perature is reached. This therm ostat is installed on the engine block. The sam e therm ostat is used in both w inter and sum m er. R efer to Section 6B-Engine Cooling for additional inform ation. A -10 Wheel Bearings For norm al application, clean and repack front wheel bearings with a high m elting point wheel bearing lubricant at each front brake lining replacem ent or 30,000 miles (48 000 km) on light duty emissions 12,000 miles (19 200 km) on heavy duty eymission or 15,000 miles (24 000 km) on diesel engine vehicles which ever comes first. For heavy duty application such as police and taxi cabs, clean and repack front wheel bearings at each front brake lining replacem ent or 15,000 miles (24 000 km ) which ever comes first. Use W heel Bearing L ubricant G M P art N o. 1051344 (one pound), 1052356 (35 pounds) or Exxon Ronex M P Grease or equivalent. This is a prem ium high m elting point lubricant. "Long fiber" or "viscous" type lubricant should not be used. Do not mix wheel bearing lubricants. Be sure to thoroughly clean bearings and hubs of all old lubricant before repacking. NOTICE: T apered roller bearings used in this vehicle have a slightly loose feel when properly adjusted. They m ust never be over tightened (preloaded) or severe bearing dam age m ay result. R efer to Section 3C for proper detailed adjustm ent procedures and specifications. A -1 1 Manual Steering Gear The steering gear is factory-filled with steering gear lubricant. Seasonal change of this lubricant should not be perform ed and the housing should not be drained-no lubrication is required for the life of the steering gear. Inspect for seal leakage (actual solid grease-not just oily film). If a seal is replaced or the gear is overhauled, the If the vehicle was not used mainly under any of these conditions, change the fluid and service screen each 100,000 miles (160 000 km) on light duty emissions and diesel engine vehicle or 24,000 miles (38 400 km) on heavy duty emissions. It takes only one pint (0.5 liter) to raise level from "A d d " to "F u ll" with a hot transmission. SECTION B SAFETY MAINTENANCE B-l Owner or Driver Safety Checks The m aintenance Schedule in the glove box lists items to be checked by the owner or driver. B-2 Tires, Wheels, and Disc Brakes During tire rotation, check disc brake pads for wear, and surface condition of rotors while wheels are removed (see Item A-7). Check tires for excessive or abnorm al wear, or dam age. Also check tire inflation pressures and adjust as shown on Tim e P lacard (located on left front door). Be sure wheels are not bent or cracked and that wheel nuts have been tightened to the torque value shown Section 3E. B-3 Exhaust System (Also an LD Emission Control Service) C heck the com plete exhaust system , including the catalytic converter. Check body areas near the exhaust system and also the tailgate. Look for broken, dam aged, missing, or out-of-position parts. Also, inspect for open seams, holes, loose connections, or other conditions which could cause a heat buildup in the floor pan, or could let exhaust fumes seep into the passenger com partm ent. D ust or w ater in the passenger com partm ent may indicate a leak L IG H T T R U C K SE RV IC E M A N U A L OB-16 MAINTENANCE AND LUBRICATION in the area. N eeded repairs should be m ade at once. To help m aintain system integrity, replace the exhaust pipes and resonators rearw ard of the muffler whenever a new muffler is put on. R efer to S ection 6F for ex h au st system repair procedures. B-4 Suspension and Steering Check front and rear suspension, and steering system. Look for dam aged, loose, or missing parts; also for parts showing signs of w ear, or lack of lu b ricatio n . R eplace questionable parts at once. R efer to Section 3B for steering and Section 3C and 3D for suspension repair procedures. B-5 Brakes and Power Steering Check lines and hoses for proper hook-up, binding, leaks, cracks, chafing, etc. Any questionable parts should be replaced or repaired a t once. W hen rubbing or wear is noted on lines or hoses, the cause m ust be corrected at once. Refer to Section 5 for brakes and Section 3B for power steering repair procedures. B-6 Engine Drive Belts W hen adjusting a drive belt, it is im portant th at the proper adjustm ent specification be used. Refer to Section 6A for engine m echanical additional inform ation. A "U sed " belt is one th at has been rotated at least one com plete revolution on engine pulleys. This begins the "seating" of the belt and it should never be reset to "N ew " belt specifications. B-7 Drum Brakes and Parking Brake (See Item B-2 for disc brake check.) Check drum brake linings for wear or cracks. Also inspect other brake parts at each wheel, such as drum s, wheel cylinders, etc. Check parking brake adjustm ent also when inspecting drum brake linings. Check brakes more often if conditions and habits result in frequent braking. Refer to Section 5 for brake repair procedures. B-8 Throttle Linkage Check for dam aged or missing parts, interference or binding. Fix any problems at once. Refer to Section 6C for fuel system repair procedures. (Also an Emission Control Service) B-9 Bumpers Check belts driving the fan, A IR pump, generator, power steering pump, and the air conditioning compressor. Look for cracks, fraying, wear, and proper tension. A djust or replace as needed. Frayed or cracked belts should be replaced and tensioned to specifications using a strand tension gage, such as tool J-23600 or equivalent. Loose belts may place an extrem ely high im pact load on driven component bearings due to the whipping action of the belt. An over tightened belt places unnecessary loads on the component bearings. In the C h art (Fig. OB-14), the m inim um reading is the lowest allowable setting before the belt m ust be reset. W hen readjusting, the adjustm ent specification should be met. C heck front and re ar bum per system s for proper im pact protection and clearance. Check also when a bum per looks out of position or if it was struck h ard -ev e n if no dam age can be seen. Refer to Section 2B for bum per repair procedures. B-10 Fuel Cap, Fuel Lines and Fuel Tank (Also an Emission Control Service) Check the fuel tank, cap and lines for dam age or leaks. Rem ove fuel cap, check gasket for an even filler neck im print, and any dam age. Replace parts as needed. Refer to Section 6C for fuel system repair procedures. SECTION C EMISSION CONTROL MAINTENANCE ALL L6 ENGINES AND ALL V8 ENGINES EXCEPT DIESEL GENERATOR A.I.R. PUMP P/S PUMP 50 LB. (222 N) MIN. A/C COMPRESSOR 65 LB. (289 N) MIN. ADJUST TO 75 + 5 LBS. USED (334 ± 22 N) ADJUST TO 125 ± 5 LBS. NEW (556 + 22 N) ADJUST TO 95 ± 5 LBS. USED (423 + 22 N) ADJUST TO 140 ± 5 LBS. NEW (623 ± 22 N) 5.7L — V8 DIESEL GENERATOR P/S PUMP A.I.R. PUMP (NON A/C) 70 LB. (311 N) MIN. A/C COMPRESSOR A.I.R. PUMP 80 LB. (356 N) MIN. ADJUST TO 75 ± 5 LBS. USED (334 ± 22 N) ADJUST TO 110-140 LBS. NEW (480-623 N) ADJUST TO 90 ± 5 LBS. USED (400 ± 22 N) ADJUST TO 135-165 LBS. USED (600-734 N) Fig. 0B-14--Engine Drive Belt Chart LIG H T TR U C K SE RV IC E M A N U A L Refer to Sections 6C or 6E for procedures needed to service the items below: C -l Thermostatically Controlled Air Cleaner Check all hoses and ducts for correct hookup. Be sure valve works properly. C-2 Carburetor Choke and Hoses Check th at choke and vacuum break work properly. C orrect any binding caused by dam age or gum on the choke shaft. Check hoses for proper hookup, cracks, rubbing, or decay, correct as needed. C-3 Engine Idle Speed A djust to the specifications shown on the underhood label. Use calibrated test equipm ent. MAINTENANCE AND LUBRICATION C-4 Early Fuel Evaporation (EFE) System C heck th a t valve works properly, correct any binding. Check th a t therm al vacuum switch works properly. Check hoses for cracks, rubbing, or decay. R eplace parts as needed. C-5 Carburetor Mounting Torque mounting bolts an d /o r nuts a t mileage shown on M aintenance Schedule. C-6 Vacuum Advance System and Hoses C heck th at system works properly. Check hoses for proper hookup, cracks, rubbing or decay. R eplace parts as needed. OB-17 boot fit a t distributor cap and spark plugs. Replace wire if dam aged or if corrosion cannot be cleaned. C-10 Idle Stop Solenoid C heck th a t p arts work properly. R eplace them as needed. C -11 Spark Plugs Replace as shown on Schedule. Use the type listed in O w ner’s and D river’s M anual. C-12 Engine Timing and Distributor Cap C-7 Fuel Filter A djust tim ing to underhood label specifications. Check the inside and outside of the cap and rotor for cracks, carbon tracking and corrosion. Clean or replace as needed. R eplace at m ileage shown on M aintenance Schedule or sooner if clogged. C-13 Air Cleaner Element C-8 PCV System Replace at m ileage showrr on Schedule. Replace more often under dusty conditions. Check th a t system works properly each 15,000 miles (24 000 km ) - Light D uty Emission or 12,000 miles (19 200 km) - Heavy Duty Emissions. PCV Valve and Filter - Replace the valve, filter and worn or plugged hoses each 30,000 miles (48 000 km) Light D uty Emissions or 24,000 miles (38 400 km) - Heavy Duty Emissions. C-14 Evaporation Control System (ECS) Check all fuel and vapor lines and hoses for proper hookup routing and condition. Check th at bowl vent and purge valves work properly, if equipped. Remove canister, check for cracks or dam age. Replace as needed. Replace canister filter. C-9 Spark Plug Wires C -15 EGR System Check Clean wires. Remove corrosion on term inals. Check the wires for checks, burns, cracks or other dam age. Check the Check E G R system for proper operation at interval shown in M aintenance Schedule. L IG H T T R U C K SERVICE M A N U A L OB-18 MAINTENANCE AND LUBRICATION SPECIFICATIONS RECOMMENDED FLUIDS AND LUBRICANTS USAGE FLUID/LUBRICANT Pow er steerin g system and pum p reservoir C on ventiona l tra n sfe r case GM p o w e r steering flu id Part No. 1050017 o r equivalent. DEXRON®-ll A u to m a tic T ra n sm issio n Fluid M anual ste ering gear L u b ric a n t GM Part No. 1051052 o r e q u ivale n t D iffe re n tia l — S tandard o r locking^M anual T ra n sm issio n , SAE-80W GL-5 o r SAE-80W-90 GL-5 gear lu b ric a n t (SAE-80W — GL-5 in Canada) Brake system and m aster c y lin d e r D elco S uprem e 11 flu id o r DOT-3 C lutch Lin kage (Man. Trans, only) a. P ivot po in ts b. Push rod to c lu tc h fo rk jo in t, and cross shaft pressure fittin g a. E ngine oil b. C hassis grease m eeting re q u ire m e n ts of GM 6031-M Manual T ransm ission S h ift Linkage, colum n s h ift P ropeller sh aft slip jo in t Chassis Grease S hift Linkage, flo o r s h ift E ngine oil Hood Latch Assem bly a. Pivots and sp ring a n c h o r b. Release pawl a. E ngine Oil b. Chassis Grease H ood and D oor H inges E ngine Oil A u to m a tic Transm ission S h ift Linkage E ngine Oil Chassis L u b rica tio n C hassis grease m eeting re q u ire m e n ts of GM 6031-M “ SF” E n g in e O il c o n fo rm in g to GM Specs. 6048M E ngine (G asoline) E ngine (Diesel) "S F /C C " or "S F /C D " E ngine Oil c o n fo rm in g to GM specs GM 6049M C on sta nt V e locity U niversal J o in t GM L u b ric a n t Part No. 1052497 o r eq u ivale n t A u to m a tic T ransm ission DEXRON®-ll A u to m a tic T ransm ission Fluid P arking Brake Cables Chassis grease W heel bearings lu b ric a n t GM Part No. 1051344 (One F ront Wheel B earings Pound) 1052356 (35 pounds) o r E xxon R onex MP Grease or equivalent. B ody d o o r hinge pins, ta ilg a te hinge and linkage, fo ld in g seat, fuel d o o r hinge W in d sh ie ld W asher S olvent E ngine C o o la n t Key Lock C ylin d e r E ngine Oil GM O ptikleen w asher solvent Part No. 1051515 o r e quivalent M ixtu re of w a te r and high q u a lity Ethylene G lycol base type antifreeze c o n fo rm in g to GM Spec. 1899-M WD-40 Spray L u b ric a n t or e q u ivale n t Fig. OB-15— Recommended Fluid & Lubricants L IG H T T R U C K SERVICE M A N U A L MAINTENANCE AND LUBRICATION OB-19 CAPACITIES S • r<,M D ifferential 8% '' Ring Gear 8 -7 /8 ” Ring Gear 101/2 " Ring Gear (Chev.) 10%'' Ring Gear (Dana) 9% " Ring Gear (Dana) 12%'' Ring Gear (Dana) Engine Crankcase 250 L6 — Drain & Refill — w /F ilte r Change 292 L6 — Drain & Refill — w /F ilte r Change 305 V 8 ) _ . . _ .... op-f. wc> ( - Drain & R efill i w/FM ,erChan9e 400 V 8 454 V 8 - Drain & Refill — w /F ilte r Change 350 V8 Diesel Including F ilte r Transmission A u to m a tic 350 — Total - Refill 400 — Total - Refill Manual 4 Speed 1 17mm 3 Speed 76mm 3 Speed 77mm Four Wheel Drive F ro n t Axle Transfer Case Fuel Tank Pickup — C10-35, K10-25 & Crew Cab (Except 107 Models) 107 Models A u x ilia ry Tank Van — Standard — Optional Suburban — Standard — O ptional — O ptional Blazer/Jim m y — Standard — Optional P10, 15/20-35 P30042 P30032 IMPERIAL MEASURE U.S. MEASURE 1.9L 4% pts. 3Y2 pts. 2.8L 3L 2.6L 11.7L 31/2 pts. 6% pts. 7.2 pts. 6.0 pts. 26.8 pts. 3 pts. 5% pts. 5% pts. 5 pts. 21% pts. 3 .8L 4 .7L 4 .7L 5.7L 4 5 5 6 qts. qts. qts. qts. 3% qts. 4% qts. 414 qts. 5 qts. 3.8L 4.7 L 4 qts. 5 qts. 31A qts. 5.7L 6 .6L 6 .6L 6 qts. 7 qts. 7 qts. 5 qts. 5% qts. 5% qts. 9 .5 L 2.8L 10.4L 3.8L 10 qts. 3 qts. 11 qts. 3.5 qts. 8% qts. 2% qts. 9% qts. 3 qts. 3 .8L 1.4L 1.4L 4 qts. 1.5 qts. 1.5 qts. 3% qts. VA qts. VA qts. 2.4L 2 .4L 2.5 qts. 2.5 qts. 2.qts. 2 qts. 76 L 60.5 L 83 L 125L 95 L 117L 151 L 95 L 117L 117L 114L 151 L 20 gal. 16 gal. Same as Main Fuel Tank 22 gal. 33 gal. 25 gal. 31 gal. 40 gal. 25 qal. 31 gal. 31 gal. 30 gal. 40 gal. 4% qts. 16.8 gal. 13.3 gal. 18% gal. 27% gal. 20.8 gal. 25.8 gal. 33.3 gal. 20.8 gal. 25.8 gal. 25.8 gal. 25 gal. 33.5 gal. Fig. 0B-16--Lubricant and Fluid Capacities LIG H T T R U C K SE RV IC E M A N U A L 0B-20 MAINTENANCE AND LUBRICATION COOLING SYSTEM Capacity (Qts./Liters) Engine Series C K10-15 C 20-25 250 CID L6 G 10-30, 15-35 C 20-25 292 CID L6 305CID V8 C K30-35 P10-30, 15-35 C K10-15 G10-15 C K 10-30 15-35 P20-35 350 CID V8 G 10-30 G 15-35 K20-25 400 CID V8 454 CID V8 G20-25 G30-35 C20-30 25-35 P30-35 (42) P30-35 (32) U.S. Measure 15 15% 15 15!4 Imperial Measure Air Cond. Man. Auto Man. Auto Man. X X X X X X X ' X X X X (14L) (14.5L) (14L) (14.5L) 121/2 13 12% 13 17 14% X X 15 (14L) 1514 (14.5) 14% (13.7L) 15 (14L) 13% (12.7L) 17% (16.5L) 19 (18L) 20 (19L) 17% (16.5L) 18 (17L) 161/2 (15.6L) 17 (16L) 121/2 13 12 121/2 11% 14% 15% 16% 14% 15 13% 14% X X X X X X X X X X X X X X X X X X 20 (19L) 16% X 18 (17L) 19 (18L) 15 15% X 20 (19L) 20 (19L) 20 (19L) 21 (20L) 23 (21.7L) 16% 16% 16% 17% 19% 24 (22.7L) 24% (2 3 L )* 20 20% 19% 20% 23% (2 2 .2 L) 241/2 (23L) Auto X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X Fig. 0B-17--Cooling System L IG H T T R U C K SE R V IC E M A N U A L H.D. Radiator Transmission X X X X X X X HEATER 1A-1 SECTION 1A HEATER CONTENTS S tan d ard H e a te r................................................................................................ 1A-1 A uxiliary H e a te r ............................................................................................... 1A-15 Specifications...................................................................................................... 1A-19 STANDARD HEATER INDEX G eneral D escription................. .......................................... System C om ponents........................................................ System C o n tro ls............................................................... Diagnosis............................................................................... On Vehicle Service Blower M otor..................................................................... H eater D istributor and Core Assem bly...................... 1A-1 1A-3 1A-3 1A-4 1A-8 1A-8 H eater H o ses......................................................................1A-9 C enter D istributor D uct - G M odels.......................... .1A-12 Defroster D u c t....................................................................1A-12 Control A ssem bly..............................................................1A-12 Control C ab les.................................................................. .1A-13 Blower S w itch.....................................................................1A-13 Resistor U n i t ......................................................................1A-15 GENERAL DESCRIPTION H eating com ponents are attach ed to the dash panel on th e rig h t side of th e vehicle. T h e blow er and air inlet assem bly and w ater hoses are located on the forw ard side of the dash panel while the heater core and distributor duct are on the passenger side. The heater system is an air mix type system in which outside air is heated and then mixed in varying am ounts with cooler outside air to attain the desired air tem perature. The system consists basically of three parts: (1) the blower and air inlet assem bly, (2) the heater distributor assembly and (3) the heater control assembly. HEATER AIR FLOW SCHEMATIC C-K Series heater airflow is shown in Fig. 1A -1. LIG H T T R U C K SERVICE M A N U A L 1A-2 HEATER HE A T E R A D E F R O S T E R A S M HEATER A DEFROSTER A S M AIR OUTLET AIR OUTLET VIEW A STEERING COLUMN VIEW B DEFROSTER DUCT A S M INST PANEL HEATER C O N T R O L & V IE W A AI R F L O W LEGEND C-K MODELS Q] TEMPERATURE V A L V E [ [jjj DEFROSTER VALVE [3] PURGE VALVE Fig. 1A-1--Heater Air Flow Schematic--C-K Models L IG H T T R U C K SERVICE M A N U A L f e j ] O U TS ID E AIR M I X E D AIR H I H E A T E D AI R HEATER BLOWER AND AIR INLET ASSEMBLY The blower and air inlet assem bly draw s outside air through the outside air inlet grille located forward of the windshield reveal-m olding and channels the air into the heater distributor assembly. The operation of the blower motor is controlled by the FA N switch on the heater control. The m otor is connected in series with the FA N switch and also the blower resistor assembly. Located in the fuse block, in series between the blower motor and the battery, is a 25 amp. fuse C -K models, a 20 am p fuse on G models. HEATER DISTRIBUTOR ASSEMBLY T he heater distributor assembly houses the heater core and the doors necessary to control mixing and channeling of the air. Since the unit has no w ater valve, w ater circulation keeps the core hot a t all times. T h at portion of the air passing through the core receives m axim um heat from the core. A ir entering the distributor assembly is channeled as follows: 1A-3 assembly, by the purge door. If the purge door is closed, then air is directed through an d /o r around the heater core by the tem perature door. A ir is then directed into the passenger com partm ent through the heater (floor) outlets an d /o r the defroster (dash) outlets by the defroster door. The tem pera­ ture of the outlet air is dependent on the ratio of heated to unheated air (controlled by the tem perature door). G Models A ir flow is controlled by doors in the d istrib u to r assembly. The air door can be adjusted to vary airflow. If air is allowed to en ter the d istrib u to r assem bly, it is then directed through an d /o r around the heater core by the tem perature door. Air is directed into the passenger com ­ partm ent through the heater (floor) and/or defroster (dash) outlets by the defroster door. The tem perature of the outlet air is dependent of the ratio of heated to unheated air (controlled by the tem perature door). C-K Models CONTROLS A ir entering the distributor can be directed out the purge door opening, on the right end of the distributor H eater controls for C-K and G Models are shown in Fig. 1A-2 and 1A-3. LIG H T T R U C K SERVICE M A N U A L 1A-4 HEATER DIAGNOSIS CAUSE AND CORRECTION TROUBLE Temperature o f heater a ir a t outlets too low to heat up pas­ senger compartment. Temperature o f heater a ir a t o utlets adequate but the vehicle w ill not build up s u ffic ie n t heat. Inadequate defrosting action. Inadequate c irc u la tio n of heated a ir through vehicle. E rra tic heater operation. Hard operating or broken controls. LIG H T T R U C K SE RV IC E M A N U A L 1. See " In s u ffic ie n t Heat Diagnostic Chart". 1. Check fo r body leaks such as: Floor side kick pad v e n tila to rs p a r tia lly open. 2. Leaking grommets in dash. 3. Leaking welded seams along rocker panel and windshield. 4. Leaks through access holes and screw holes. 5. Leaking rubber molding around door and windows. 6. Leaks between sealing edge of blower and a ir in le t assembly and dash, and between sealing edge o f heater d is trib u to r assembly and dash. 1. Check that DEFROST lever completely opens defroster door in DEF position - Adjust i f necessary. 2. Insure that temperature and a ir doors open f u lly - Adjust. 3. Look fo r obstructions in defroster ducts - Remove any obstructions. 4. Check for a ir leak in ducting between defroster o u tle t on heater assembly and defroster duct under instrument panel Seal area as necessary. 5. Check position of bottom o f nozzle to heater locating tab Adjust. 6. Check position of defroster nozzle openings re la tiv e to in s tru ­ ment panel openings. Mounting tabs provide positive position i f properly in s ta lle d . 1. Check heater a ir o u tle t fo r correct in s ta lla tio n - R e in s ta ll. 2. Inspect flo o r carpet to insure that carpet lie s f l a t under fro n t seat and does not obstruct a ir flow under seat, and also inspect around o u tle t ducts to insure that carpet is well fastened to flo o r to prevent cupping of a ir flow - Correct as necessary. 1. Check coolant level - F ill to proper le v e l. 2. Check fo r kinked heater hoses - re lie v e kinks or replace hoses. 3. Check operation of a ll bowden cables and doors - Adjust as necessary. 4. Sediment in heater lines and ra d ia to r causing engine thermo­ s ta t to stick open - flush system and clean or replace thermo­ s ta t as necessary. 5. P a r tia lly plugged heater core - backflush core as necessary. 1. Check fo r loose bowden cable tab screws or mis-adjusted bowden cables - Correct as required. 2. Check fo r sticking heater system door(s) - Lubricate as required using a silico ne spray. HEATER 1A-5 INSUFFICIENT HEAT D IA G N O S IS Position the controls so that the: Temperature lever is on full heat. Selector or heater lever is on Heater. Fan switch is on Hi. •CHECK DUMP DOOR OUTLET FOR AIR FLOW AIR FLOW NO AIR FLOW I ~ I A d ju st d u m p d o o r fo r n o air flo w . CHECK DEFROSTER OUTLETS FOR AIR FLOW ~| (If in doubt as to High or Low air flow set selector on DEF which is High and compare. Reset selector on Heater) HIGH AIR FLOW NO OR LOW AIR FLOW T..............— | Adjust defroster door for low air flow. | CHECK HEATER OUTLET AIR FLOW (If in doubt, switch fan switch from Hi to Lo) CHANGE IN AIR FLOW NORMAL AIR FLOW LITTLE OR NO CHANGE IN AIR FLOW | 1 LOW OR NO AIR FLOW~| Check heater outlet temperature with 220° F range thermometer. “ Check shutoff door position for full system air flow. Adjust if necessary. (approximate outlet air temperatures) Outlet Air Ambient Air 145 0 . 150... 25 5b 40 ... 165 75 | LOW AIR FLOW | NO AIR FLOW | I NORMAL TEMPERATURE | Check heater outlet for obstruction - re­ move. I Remove all obstructions under front seat. Check motor voltage at closest motor line connection with a voltmeter. Car does not build up heat - operate vent controls and see that the air vent doors close completely, if not, adjust. CHECK FUSE FUSE BLOWN - replace fuse. I = AIR FLOW - system okay. LOW TEMPERATURE UNDER 10 VOLTS Check battery volts - under 10 volts, recharge then recheck motor voltage. Check coolant level; if low, fill. Look for or feel all radiator and heater hoses and connections for leaks. Repair or replace. Check the radiator cap for damage and re­ place if required. Check wiring and connections for under 10 volts from motor to fan switch. Repair or replace last point of under 10 volt reading. Check heater and radiator hoses for kinks straighten and replace as necessary. Check temperature door for max heat po­ sition. Adjust if necessary. ; BLOWS FUSE OVER 10 VOLTS | X (Check the system temperature after re­ pairing the item checked to complete the diagnosis.) _____ | I Remove positive lead from motor and replace fuse. ____ FUSE REMAINS OK - remove motor and check for obstruction in system opening, if none, REPLACE MOTOR. If obstruction, remove material and re-install motor. BLOWS FUSE - check for shorted wire in blower electric circuit See Heater Circuit Diagnostic Chart. Apply external ground, (jumper wire) to motor case. INCREASED AIR FLOW repair ground. HEATER CORE FUSE OK I Feel temperatures of heater inlet and outlet hoses. --------------T ------------- --------------------- WARM INLET AND OUTLET HOSES SAME AIR FLOW - remove motor and check for obstruction in system open­ ing. If none, REPLACE MOTOR. If obstruction, remove material and re­ install motor. FUSE OK - See Heater Circuit Diagnostic Chart. Check engine thermostat. HOT INLET AND WARM OUTLET HOSES I Check pulleys, belt tension, etc., for pro­ per operation. Replace or service as neces­ sary. ’ CHECK FOR C K MODELS ONLY 'CHECK FOR G MODELS ONLY X Remove hoses from heater core. Reverse flush with tap water. If plugged, repair or replace. LIG H T T R U C K SERVICE M A N U A L HEATER CIRCUIT D IA G N O S I S * BLOWER MOTOR INOPERATIVE (AN Y SPEED) I Check fuse in fuse panel. T FUSE BLOWN FUSE OK 1........ " With Ignition switch in "R U N " position and blower speed switch "O N " use meter to locate short in one of the follow ing wires: 1. From fuse panel to blower speed switch. 2. From blower speed switch to heater resistor. 3. From heater resistor to blower. Note: Short circuit may be interm ittent. If meter does not indicate a short circuit, move harness around as much as possible to re-create short circuit. Watch and listen fo r arcing. 1----- The follow ing tests should be made w ith the ignition switch in "R U N ” position the blower speed switch "O N " and the lever on heat position. _L Check blower motor ground X POOR OR NO GROUND I 1 GROUND OK X T Repair ground Check m otor connector w ith 12 volt test light. LAMP LIGHTS I -------------- J------------ 1 LAMP DOES NOT LIGHT 1 Replace Motor I Check blower feed wire in connector on resistor w ith 12 volt test light. r LAMP DOES NOT LIGHT X Use 12 volt test light and check feed terminal (brown) on blower speed switch. LA M P L IG H T S 1 .. 1 _ Repair open in feed wire from resistor to blower motor. ‘ See heater circuit diagrams HEATER 1A-7 Fig. lA-4--Heater Wiring Diagrams LIG H T T R U C K SE RV IC E M A N U A L 1A-8 HEATER ON VEHICLE SERVICE BLOWER MOTOR Removal (Fig. 1A-5) 1. Disconnect battery ground cable. G Models - Remove the coolant recovery tank, and power antenna as outlined in Sections 6 and 9. 2. Disconnect the blower motor lead wire. 3. Remove the five blower motor m ounting screws and remove the m otor and wheel assembly. Pry gently on the blower flange if the sealer acts as an adhesive. 4. Rem ove th e blow er wheel to m otor sh aft nut and separate the wheel and m otor assemblies. 5. To install a new m otor, reverse Steps 1-4 above. The following steps should be taken to assure proper installation: a. Assem ble the blower wheel to the motor with the open end of the wheel away from the blower motor. b. If the motor m ounting flange sealer has hardened, or is not intact, remove the old sealer and apply a new bead of sealer to the entire circum ference of the m ounting flange, c. Check blower operations: blower wheel should rotate freely with no interference. HEATER DISTRIBUTOR AND CORE ASSEMBLY C-K Models Replacement (Fig. 1A-6) 1. Disconnect the battery ground cable. 2. Disconnect the heater hoses at the core tubes and drain engine coolant into a clean pan. Plug the core tubes to prevent coolant spillage at removal. 3. Remove the nuts from the d istrib u to r duct studs projecting into the engine com partm ent. 4. Remove the glove box and door assembly. 5. D isconnect the A ir-D efrost and T e m p eratu re door cables. 6. Remove the floor outlet and remove the defroster duct to heater distributor duct screw. 7. Remove the heater distributor to dash panel screws. Pull the assembly rearw ard to gain access to wiring harness and disconnect all harnesses attached to the unit. 8. Remove the heater-distributor from the vehicle. 9. Remove the core retaining straps and remove the core. 10. To install, reverse Steps 1-9 above. Be sure core to case and case to dash panel sealer is intact before assem ­ bling unit. G Models Replacement (Fig. 1A-7) 1. Disconnect the battery ground cable. 2. Remove coolant recovery tank and lay aside. 3. Place a clean pan under the vehicle and then disconnect th e heater core inlet and ou tlet hoses at the core L IG H T T R U C K SERVIC E M A N U A L HEATER 1A-9 VIEW A Fig. lA-7--Heater Distributor - G Models 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. connections (see "H e a te r H oses-R eplacem ent" later in this section). Quickly plug the heater hoses and support them in a raised position. Allow the coolant in the heater core to drain into the pan on the floor. Rem ove h eater d istrib u to r du ct to d istrib u to r case attaching screws and distributor duct to engine cover screw and remove duct. Remove engine housing cover. Remove instrum ent panel attaching screws: above, at w indshield, all lower screw s and rig h t lower I.P. support bracket at door pillar and engine housing. Lower steering column, and raise and support right side o fl.P . Remove defroster duct to distributor case attaching screw, and 2 screws attaching distributor to heater case. Disconnect tem perature door cable and fold cable back for access (R efer to Fig. 1A -17). Remove three (3) nuts at engine com partm ent side of distributor case and one (1) screw on passenger side. Remove the heater case and core as an assembly. Tilt the case assem bly rearw ard at the top while lifting up until the core tubes clear the dash openings. Remove the core retaining strap screws and remove the core. To install a new core, reverse Steps 1-10 above. Be sure core to case and case to dash panel sealer is intact before assem bling unit. Replacement The heater core can be easily dam aged in the area of the core tube attachm ent seams whenever undue force is exerted on them. W henever the heater core hoses do not readily come off the tubes, the hoses should be cut just forward of the core tubes. The portion of the hose rem aining on the core tube should then be split longitudinally. Once the hoses have been split, they can be removed from the tubes without dam aging to the core. HEATER HOSES H eater hoses are routed from the therm ostat housing or inlet m anifold and w ater pum p (radiator on some autom atic transm ission vehicles) to the core inlet and outlet pipes as shown in Figures 1A-8 thru 1A -1 1. Hoses are attached at each end with screw type clamps. LIG H T T R U C K SERVICE M A N U A L 1A-10 HEATER AUTOMATIC TRANSMISSION MODELS1 ( EXCEPT C-K 10 350 V8 W / O VOI OR C60 ) V -8 L-6 C-K M O D E L S TO WATER PUMP - f ^ 1v IEw [a 1 ^ C36 G M ODELS Fig. lA-8--Heater Hose Routings L IG H T T R U C K SE RV IC E M A N U A L Fig. 1A -1 1--Heater Hose Routing G Series HEATER 1A -1 1 1A-12 HEATER |vitwfA| Fig. 1A-12--Distributor Ducts--G Models DISTRIBUTOR DUCTS - G Models Replacement (Fig. 1A-12) 1. Disconnect the battery ground cable. 2. R aise I.P. at rig h t side as outlined und er heater distributor removal. 3. U nsnap the engine cover front latches. Remove the two cover to floorpan screws and remove the cover. 4. Remove the heater distributor duct to case attaching screws as shown in Fig. 1A -12. 5. Remove one (1) screw at left center of distributor duct. 6. Pull the center d istributor duct to the right and remove it from the vehicle. 7. To install, reverse Steps 1 thru 5. Check cable and door operation; cables should be free from kinks or binding and doors should close properly. If cable adjustm ent is necessary, refer to "Bowden C able-A djustm ent." A/C HEATER ASM (TYPICAL) [v i e w [ a ] DUCT ASSEMBLY DEFROSTER DUCT D efroster assemblies attach m en t are shown in Fig. 1A - 13 UPPER IP EXTENSION CONTROL ASSEMBLY C-K Models Replacement (Fig. 1A-14) 1. Disconnect the battery ground cable. 2. Remove the instrum ent panel bezel. 3. Disconnect the bowden cables and the blower switch wiring harness. Be careful not to kink the bowden cables. L IG H T T R U C K SE R V IC E M A N U A L Fig. 1A-13--Defroster Outlets 4. Remove the control through the opening above the control. 5. If a new unit is being installed, transfer the blower switch to the new unit. 6. To reinstall, reverse Steps 1 thru 4. HEATER 1A-13 3. Remove the control to instrum ent panel screws. 4. Raise or lower control as necessary to remove cable push nuts and tab attaching screws. 5. Remove glove box and door as an assembly. 6. Remove cable push nut and tab attaching screw at door end of cable. 7. Remove cable from retaining clip and remove cable assembly. 8. To install, reverse Steps 1 thru 7. Be careful not to kink the cable during installation. Be sure to route the cable as when removed. Check cable adjustm ent. G Models Replacement (Fig. 1A-17) Fig. 1 A -14--C ontrol Assembly, C-K M odels G Models Replacement (Fig. 1A-15) 1. Disconnect the b attery ground cable. 2. Remove I.P. bezel as outlined in Section 8C of this m anual. 3. Rem ove th e control to in stru m e n t panel m ounting screws (3) and carefully pull the control rearw ard far enough to gain access to the bowden cable attachm ents. C are should be taken to prevent kinking the bowden cables while lowering the control. 4. Disconnect the bowden cables, the control illum ination bulb, the blower sw itch connector and rem ove the control from the vehicle. 5. Rem ove th e blower sw itch screw s and rem ove the blower switch. 6. To install, reverse Steps 1 thru 4. CONTROL CABLES (Fig. 1A-16, 1A-17) C-K Models Replacement 1. Disconnect the battery ground cable. 2. Remove the instrum ent panel bezel. H eater and defroster cable routing and attachm ent to control and to distributor case is shown in Fig. 1A -17. If cable adjustm ent is required, refer to A djustm ent, C-K Series. Adjustment - C-K Series 1. Disconnect the battery ground cable. 2. Remove glove box and door as an assembly. 3. Pry off the appropriate cable eyelet clip and disconnect the cable from the door. 4. Remove the cable retaining screw. 5. W hile holding the cable with pliers, rotate the m ount­ ing tab on the cable to lengthen or shorten the cable, whichever is required. NOTICE: Do not pinch the cable too tightly or dam age to the cable could result. 6. Install the cable, reversing Steps 1-4 above. Adjustment - G Van 1. A ttach inner cable and sheath to I.P. Control. 2. W ith I.P. installed, move tem perature cable to cold and attach loop on inner cable to tem perature door on heater case. 3. A ttach cable sheath to heater case. 4. Move tem perature lever to full heat. This will require some effort due to force required to slide inner cable clip to its proper position. BLOWER SWITCH C-K Models Replacement (Fig. 1A-14) 1. Disconnect the battery ground cable. 2. Remove the instrum ent panel bezel. 3. Remove the control to instrum ent panel screws and lower the control onto the radio. 4. Disconnect the switch electrical harness. 5. Remove the switch attaching screws and remove the switch. 6. To install, reverse Steps 1-5 above. LIG H T T R U C K SERVICE M A N U A L 1A-14 HEATER Fig. 1A-16--Control Cables, C-K Series V IE W A V IE W B Fig. 1A-17--Control Cable Routing, G Models L IG H T T R U C K S fR V IC E M A N U A L HEATER 1A-15 G Models Replacement (Fig. 1A-15) 1. Disconnect the battery ground cable. 2. Disconnect the blower switch wiring harness connector at the switch. 3. Remove the two switch attaching screws and remove the switch assembly. 4. To install a new switch, reverse Steps 1 thru 3. RESISTOR Replacement (Figs. 1A-5 and 1A-18) 1. Disconnect the wiring harness at the resistor connector. 2. Remove the two resistor m ounting screws and remove the resistor. 3. To install a new resistor, reverse Steps 1 and 2 above. AUXILIARY HEATER INDEX G eneral Description .......................................................................................... ..1A-15 C o n tro l............................................................................................................... ..1A-15 D iagnosis.............................................................................................................. ..1A-16 On Vehicle S ervice..............................................................................................1A-17 Specifications...................................................................................... ..................1A-19 GENERAL DESCRIPTION An auxiliary heater is available as a dealer installed accessory to provide additional heating capacity for the rearm ost extrem ities of the G (05 and 06) models. This unit operates entirely independent of the standard heater and is regulated through its own controls at the instrum ent panel. This system consists of a separate core and fan unit m ounted as shown in Fig. 1A-23. H eater hoses extend from the unit to the front of the vehicle where they are connected to the standard heater hoses with " te e s" . An "on-off" vacuum operated w ater valve is installed in the heater core inlet line in the engine com partm ent. The purpose of the valve is to cut off coolant flow to th e auxiliary core d uring w arm w eather and elim inate the radiant heat th a t would result. CONTROLS Two methods of control are employed with this system: Water Valve (Refer Fig. 1A -11) W hen heat is desired, and the fan switch is any position except off, a vacuum operated water valve controlled by the switch, opens the w ater line to permit hot w ater circulation through the heater core. In the O FF position the valve is closed to prevent unw anted heat during warm weather. Fan Switch (Fig. 1A-20) The three speed fan switch (L O W -M E D -H I) is located in the instrum ent panel, to the right of the steering column. LIG H T T R U C K SERVICE M A N U A L 1A-16 HEATER DIAGNOSIS R efer to the "S tan d ard H eater" section of this m anual for diagnostic inform ation; R efer to Electrical D iagram Fig. 1A-21. LIG H T T R U C K SE RV IC E M A N U A L HEATER 1A-17 rjrrw77m n rmarTTTuri 'iM n.f'g’m m i r r u .iB i 29737818905426 -3 •3 ■2984092 |3 3 W HT-952 BRN/WHT-5' 2 ■2 TEL-51----LT BLU-72 8905426 BRN/WHT-50 — W H T-952A — -3 BRN/WHT-50-3 WHT-952A■2 WHT-952B- 2984092 REAR BLO. RESISTOR i! 8905426 ■2 LT BLU-72 — YE l-51 — 2984092 2 9 8 9 5 7 6 GROMMET- G Series FUSE PANEL Fig. 1A -2 1--Electrical Diagram ON VEHICLE SERVICE Since a detailed list o f installation instructions is included with the auxiliary heater unit, replacement proce­ dures will not be repeated in this section. On G ModeIs--When replacing heater hoses, maintain a 1/2 in. minimum clearance between hose clip and upper control arm, a 1-1/2 in. minimum clearance between hoses and propshaft and a 1-1/4 in. minimum clearance between the auxiliary heater core lines and the exhaust pipe as shown in Fig. 1A-24. All Models--Draw hoses tight to prevent sag or rub against other components. Be sure to route hoses through all clamps as originally installed. LIG H T T R U C K SERVICE M A N U A L 1A-18 HEATER LIG H T T R U C K SE RV IC E M A N U A L HEATER SPECIFICATIONS SECTION 1A HEATER V olts Am ps. (C old) RPM (Cold) Blower Motor C-K Models 13.5 6.25 Max. G Models 13.5 7.1 Max. 2550 2950 2850 3250 Min. Max. Min. Max. Fuses C-K Models G Models A U XILIA R Y HEATER Volts Blower Motor . . . . 13.5 Amps. (Cold) 9.6 Max. RPM (Cold) 2700 Min. 1A-19 . Kfei*! ;: ■. ^ r \ J> ‘ kl ■ -i < ,Kr ' AIR CONDITIONING IB-1 SECTION IB AIR CONDITIONING NO TICE: W hen perform ing air conditioning diagnosis on Chevrolet vehicles equipped with a catalytic converter, it will be necessary to warm the engine to a norm al operating tem perature before attem pting to idle the engine for periods g reater than five (5) minutes. Once the choke is open and fast idle speed reduced to a norm al idle, diagnosis and adjustm ents can be m ade. CONTENTS G eneral D escription............................................................ C60 System (C -K & G M odels).................................. O verhead Systems (C -K & G M o d e ls)...................... M otor Home Chassis S y stem ........................................ Pressure Cycling S w itch............................................... System C o n tro l................................................................. D iagnosis............................................................................... Leak Testing The R efrigerant S y s te m ....................... Pressure Cycling System D iagnosis............................. Com pressor Diagnosis...................................................... Insufficient Cooling........................................................... Electrical System D iagnosis.......................................... E vacuating and C harging Procedures............................ Air Conditioning System C a p a c ity .............................. Checking O il...................................................................... On Vehicle S erv ice............................................................. C o m p resso r........................................................................ C60 S y ste m -C -K M o d els.............................................. C ondenser............................................................................ A ccum ulator-A ll............................................................. Blower A ssem b ly ...........................................................; E vaporator C ore.............................................................. Expansion T ube-A ll....................................................... Selector D uct and H eater C o re.................................. Kick Panel A ir Valve..................................................... Plenum A ir V a lv e .......................................................... Control A ssem b ly .......................................................... T em perature Door Cable A d ju stm e n t................... M aster Switch an d /o r Blower S w itch....................... V acuum T a n k ................................................................. Blower Resistor U n it..................................................... Blower M otor R e la y ...................................................... F u se ...................................................................................... Overhead S y stem -C -K M odels.................................... IB-3 IB-3 IB-3 IB-3 IB-5 IB-7 IB-12 IB-12 IB-13 IB-16 IB-28 IB-28 IB-29 IB-29 IB-29 IB-29 IB-35 IB-38 IB-38 IB-38 IB-38 IB-38 IB-38 IB-40 IB-40 IB-40 IB-41 IB-41 IB-41 IB-41 IB-42 IB-42 IB-42 IB-42 R ear D u c t.......................................................................... .IB-42 Blower M otor R e sisto r................................................... .IB-43 Blower M otor A ssem bly................................................. IB-43 Expansion V a lv e ............................................................. IB-44 Evaporator C ore................................... .......................... IB-45 Blower M otor Sw itch......................................................IB-45 F u se .................................................. ..................................IB-45 C60 S y ste m -G M o d els.................................................. .IB-46 C ondenser......................................................................... .IB-46 A /C Air D istributor D u c t........................................... .IB-46 A /C C enter and R ight Dash Outlets, H eater, A ir D istributor and Extension D u c ts .......IB-46 H eater Core Case and C o re .........................................IB-46 Blower M o to r.................................................................. .IB-46 Evaporator C ore...............................................................IB-47 T em perature Door C able...............................................IB-48 C o n tro l.............................................................................. .IB-48 Blower S w itc h ................................................................. .IB-48 Blower M otor R e la y .......................................................IB-48 R esistors.............................................................................IB-48 BlQ^er M otor R e la y ........................................................IB-48 V acuum T a n k ................................................................. .IB-53 C ircuit B reak er................................................................IB-53 O verhead S y ste m -G M o d els.........................................IB-53 Dash M ounted S y ste m -M o to r Home U n its ..............IB-56 C ondenser......................................................................... .IB-56 R eceiver-D ehydrator.................................................... .IB-57 Sight G la ss....................................................................... .IB-57 Blower-Evaporator A ssem bly.......................................IB-57 Blower A ssem b ly ........................................................... .IB-57 Expansion Valve, Evaporator Case or C o re .............IB-59 Therm ostatic an d /o r Blower Sw itches.......................IB-59 R e sisto r..............................................................................IB-59 F u se ................................................................................... .IB-59 Specifications.........................................................................IB-60 Special T ools..........................................................................IB-61 LIG H T T R U C K SERVICE M A N U A L IB-2 LIGHT SERVICE SHROUD. M ANUAL CONTROL VIEW A 9 00 o * n3 " Q =5. AIR INLET VALVE PLENUM VALVE O HEATER CORE O /< LIG H T T R U C K SERVICE M A N U A L IB-6 CONDITIONED AIR IS D IR EC TED THRU I P. OUTLETS IN THIS MODE L E V E R POSITION, MAXIMUM COOLING IS O F F E R E D WITH THE CONDITIONED AIR DISTR IB U TED THRU I P O UTLETS AT ANY BLOWER SPEED. A NON COMPRESSOR O P E R A T I N G POSITION, W IT H OUTSIDE AIR D E L I V E R E D T H R U I P. O U T L E T S A NON COMPRESSOR O P E R A T I N G POSITION, WITH OUTSIDE AI R D I S T R I B U T E D A B O U T 80% TO FLOOR & 20% TO W /S H LD Fig. 1B-5--C60 System C O N D I T I O N E D AIR D I S T R I B U T E D AB OU T 80% TO W /S H L D & 20% TO FLOO R Controls (C-K & G Series) 4 SPEED FAN C O N T R O L LE VE R V A C U U M O P E R A T E D SYSTEM SELECTOR (MODE) L E VE R T E M P E R A T U R E L E V E R POSITION R E G U L A T E S TE M P E R A T U R E OF THE A I R E N T E R I N G THE PASSENGER C O M P A R T M E N T BY CABLE O P E R A T I O N OF THE HEATER CORE TE M P E R A T U R E D O O R AIR CONDITIONING CONDITIONED AIR IS D IR E C T E D THRU W/SHLD, I P. & FLOOR DISTRIBUTOR OUTLETS AIR CONDITIONING IB-7 Vacuum Schematic - G Models SYSTEM CONTROLS G Model vacuum schematic is shown in Fig. 1B-9. C60 SYSTEM (C-K & G SERIES) - FIG. IB-5 System Operation - C-K Truck OVERHEAD SYSTEM (C-K & G SERIES) System operation is shown in Fig. IB-6. Vacuum Schematic - C-K Truck T he C-K T ruck air conditioning vacuum schem atic is shown in Fig. IB-7. System Operation - G Models This system operates in conjunction w ith the C60 system. Since refrigerant flow is controlled by the front system, the only control provided for on the overhead system is a three-speed fan switch (LO W , M ED , H I). The fan switch is mounted in the instrum ent panel, to the right of the steeringcoloum n (Fig. IB -10). System operation is shown in Fig. 1B-8. SYSTEM OPERATIO N CK TRU CK SELECTOR LEVER POSITION COMPRESSOR BLOWER SPEEDS A V A IL AIR SOURCE AIR ENTERS VEHICLE HEATER A/C DOOROPEN TO: HEATER DEFROSTER DO OR-OPEN TO: OFF OFF LOW OUTSIDE FLOOR OUTLETS HEATER HEATER M AX A/C ON HI INSI DE% DASH OUTLETS A/C HEATER NORM A/C ON ALL OUTSIDE DASH OUTLETS A/C HEATER OUTSIDE FLOOR AND DASH OUTLETS A/C & HEATER HEATER B I-LE V E L ON ALL VE N T OFF ALL OUTSIDE DASH OUTLETS A/C HEATER HTR OFF ALL OUTSIDE FLOOR OUTLETS HEATER HEATER HEATER DEFROST DEF OUTSIDE DEFROST OUTLETS ON ALL NOTE % 100% Inside air is not available, some bleed through of outside air is allowed. Fig. 1 B-6--System Operation - C-K Truck LIG H T T R U C K SERVICE M A N U A L IB-8 AIR CONDITIONING COMPRESSOR O FF OFF BLOW ER SPEEDS A V A IL A IR SOURCE NONE O U T S ID E A IR ENTERS V E H IC L E H E A TE R A /C DOOR H E A TE R D EFR O STER DOOR OPEN TO OPEN TO HEATER H E A T E R -D E F F LO O R O U T L E T S MAX ON ALL I NSIDE % DASH O U T L E T S HEATER A /C NO RM ON ALL O UT SIDE DASH O U T L E T S HEATER A /C Bl LEV ON ALL O U T S ID E DASH O U T L E T S F LO O R O U T L E T S HEATER A /C & HEATER VENT OFF ALL O UT SIDE DASH O U T L E T S HEATER A /C H EA TER OFF ALL OUTSIDE B L E E D TO DEF RO ST & F LO O R O U T L E T S HEATER HE A T E R DEFR ON* ALL O UT SIDE DEF R O ST O U T L E T S DEF RO ST HEATER •P R O V ID E D COMPRESSOR PRESSURE SW ITCH CLOSED Fig. lB-8--System Operation - G Models VACUUM RESER VO IR (IN E N G I N E C O M P A R T M E N T ) T O VACUUM SORCE GR AY DASH P A N E L H EA TER CORE CASE P IN K . HEATER TEM PERATURE DOOR C A B L E A /C ^ HEATER D ISTRIBUTOR DUCT O U T S ID E A IR j H E A T E R AI R DEFROST CONTROL DK B L U E S E L E C T VAL VE OPER A TIN G C HART ORANGE P O R T NC . 9 2 4 1 8 HEAT DEF A / C - 0 . S. A IR H T R A IR SOURCE OFF V AC VA C VENT VA C VAC MAX VAC VENT VENT V AC V AC NO RM V AC VENT VA C VAC VAC HTR V AC VENT VENT VENT VAC DEFOG VENT VENT VENT VENT VA C DEF VENT V AC VENT VENT VAC Fig. 1B-9--Vacuum Schematic - G Models In the O F F position, the blower is inoperative; however, refrigerant is circulating in the system if the C60 System is O N . In any of the three blower positions (L O W , M ED , H I), the blower will be operative regardless if the Four-Season system is O N . LIG H T T R U C K SERVICE M A N U A L To obtain maxim um cooling, the Four-Season System should be on A /C , tem perature lever on COLD, blower switch on H I and the overhead unit blower switch should be on HI. AIR CONDITIONING IB-9 This system is self contained and is mounted below the dash by the body m anufacturer. System controls consist of an A IR knob and T E M P knob located in the center of the unit face plate (Fig. 1B -12). Air Knob Turning the A IR knob clockwise operates a three speed (L O W -M E D -H I) blower motor. Temp Knob This knob is used to control the degree of cooling desired. Fully clockwise a t C IT Y provides m axim um cooling, while tu rn in g th e knob to H IW A Y provided adequate cooling for highway operation. Reduced cooling could be encountered when operating at highway speeds with the controls at the C IT Y setting. The heater m ust be fully off to obtain maxim um cooling. CCOT SYSTEM COMPONENTS C C O T R efrigerant System components and refriger­ ant flow are shown in Fig. 1B -13. C hart 1B -1 shows pressure tem perature relationships of R -12. OVERHEAD SYSTEM (G MODELS) T his system operates in conjunction with the C60 system. Since refrigerant is controlled by the C60 system, the only control provided on the rear overhead system is a three speed blower switch (Fig. IB -11). In the O F F position, the blower is inoperative; however, refrigerant is circulating in the system if the front system is O N . To operate the rear overhead system, simply select the desired blower speed (L O W , M ED , H I). W hen air circulation only is desired, the rear A /C blower m otor m ay be operated independent of the front A /C blower m otor and w ithout the cooling function. DASH MOUNTED UNIT (MOTOR HOME CHASSIS UNITS) Refrigerant and Oil Capacities R efrigerant and oil charge is shown in C h art 1B-2. PRECAUTIONS IN HANDLING REFRIGERANT-12 (R-12) 1. Do not leave drum of R-12 uncapped. 2. Do not carry any co n tain er of R-12 in passenger com partm ent of car. 3. Do not subject any container of R -12 to high tem perature. 4. Do not weld or steam clean on or near system. 5. Do not fill drum of R-12 completely. 6. Do not discharge vapor into area where flam e is exposed. 7. Do not expose eyes to liquid. CAUTION:lf R-12 liquid should strike the eye, call a doctor immediately. Fig. 1 B-l 1--Overhead Unit Control (G Models) Fig. lB-12--Motor Home Unit Control a. DO N O T RU B T H E EYE. Splash the affected area with q u an tities of cold w ater to g radually get the tem perature above the freezing point. b. The use of an antiseptic oil is helpful in providing a protective film over the eyeball to reduce the possibility of infection. c. O btain treatm ent as soon as possible, from a doctor or eye specialist. Should liquid R-12 come into contact with the skin, the injury should be treated the same as (skin which has been frostbitten or frozen. All R-12 drum s are shipped with a heavy m etal screw cap. The purpose of the cap is to protect the valve and safety plug from dam age. It is good practice to replace the cap after each use of the drum for the same reason. If it is necessary to transport or carry any container of R-12 in a car, keep it in the luggage com partm ent. If the drum is exposed to the radiant heat of the sun, the resultant LIG H T T R U C K SERVICE M A N U A L IB -10 AIR CONDITIONING A C CUM U LA TO R PRESSURE CYCLING SYSTEM 'H P V " - H IG H PRESSURE VAPOR L E A V IN G COMPRESSOR. 'H P L " - VAPOR IS COOLED DOWN BY CONDENSER A IR FLOW A N D LEAVES AS HIG H PRESSURE L IQ U ID . 'L P L " - O R IF IC E M ETERS THE L IQ U ID R-12, IN T O EVAPO RA TO R, REDUCING ITS PRESSURE, AND W ARM BLOWER A IR ACROSS EVAPO RA TO R CORE CAUSES B O ILIN G OFF OF L IQ U ID IN T O VAPOR. 'L P V " - LEAVES EVAPORATOR AS LOW PRESSURE VAPOR A N D RETURNS W ITH THE SM A LL A M O U N T OF . . . 'Ipl" - . . . LOW PRESSURE L IQ U ID T H A T D ID N 'T BO IL OFF CO M PLETELY BACK TO THE COMPRESSOR TO BE COMPRESSED A G A IN . Fig. 1B-13--CCOT System Components REFRIGERANT — 12 PRESSURE — TEMPERATURE RELATIONSHIP The table below indicates the pressure of Refri­ gerant — 12 at various temperatures. For in­ stance, a drum of Refrigerant at a temperature of 80PF (26.6?C) will have a pressure of 84.1 PSI (579.9 kPa). If it is heated to 125°F (51.6*0, the pressure will increase to 167.5 PSI (1154.9 kPa). It also can be used conversely to deter­ mine the temperature at which Refrigerant — 12 boils under various pressures. For example, at a pressure of 30.1 PSI (207.5 kPa), Refriger­ ant — 12 boils at 32°F (O’ C). CF)( C) 21.7 - 29.8C 0(ATM0SPHERIC O(kPa) PRESSURE) 2.4 16.5 20 - 28.8C 31.0 4.5 10 - 23.3C 46.9 6.8 5 - 20.5C 63.4 9.2 0 - 17.7C 81.4 11.8 5 - 15.0C 101.4 14.7 10 - 12.2C 122.0 17.7 15 - 9.4C 145.5 21.1 20 - 6.6C 169.6 24.6 25 - 3.8C 196.5 28.5 30 - 1.1C 207.5 30.1 32 OC 224.8 32.6 35 1.6C 37.0 255.1 40 4.4C 287.5 41.7 7.2C 45 322.0 46.7 50 10. OC increase in pressure m ay cause the safety plug to release or the drum to burst. Weeding or steam cleaning near any of the refrigerant lines or com ponents of th e air conditioning system could build up dangerous and dam aging pressures in the system. If the occasion arises to fill a small R-12 drum from a large one, never fill th e drum completely. Space should always be allowed above the liquid for expansion. If the R-12 drum were com pletely full and the tem perature was increased, trem endous hydraulic force could be developed. LIG H T T R U C K SE RV IC E M A N U A L (PSIG)(kPa) f F)(°C) 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 140 12.70 15.5C 18.3C 21.1C 23.8C 26.6C 29.40 32.2C 35.00 37.7C 40.5C 43.3C 46.1C 48.8C 51.60 54.40 60. OC (PSIGNkPa) 52.0 57.7 63.7 70.1 76.9 84.1 91.7 99.6 108.1 116.9 126.2 136.0 146.5 157.1 167.5 179.0 204.5 358.5 397.8 439.2 482.7 530.2 579.9 632.3 686.7 745.3 806.0 870.2 937.7 1010.1 1083.2 1154.9 1234.2 1410.0 CAUTION:Avoid breathing smoke and fumes produced by the burning of the Refrigerant-12. Such fumes may be hazardous. One of the most im portant cautions concerns the eyes. Any liquid R-12 which may accidentally escape is approx­ imately 21°F (-6°C) below zero. If liquid R-12 should touch the eyes, serious dam age could result. Always wear goggles to protect the eyes when opening refrigerant connections. AIR CONDITIONING Refrigerant Charge Overhead System C K Models G Models 5 lbs.-4 oz. 5 lbs. C60 System 3 Lbs. -1 2 o*. 3 lbs. PRECAUTIONS IN HANDLING REFRIGERANT LINES AND FITTINGS • All m etal tubing lines should be free of kinks, because of the restriction th a t kinks will offer to the flow of R-12. The refrigeration capacity of the entire system can be greatly reduced by a single kink. • The flexible hose lines should never be bent to a radius of less th an 4 times the d iam eter of the hose. • The flexible hose lines should never be allowed to come within a distance of 63.5 mm (2-1/2 in.) of the exhaust m anifold. • Flexible hose lines should be inspected at least once a year for leaks or brittleness. If found brittle or leaking they should be replaced with new lines. • U se only new lines th a t have been sealed during storage. • Always wear safety goggles when opening refrigerant lines. • W hen disconnecting any fitting in the refrigeration system, the system m ust first be discharged of all R-12. However, proceed very cautiously regardless of gage readings. Open very slowly, keeping face and hands aw ay so th a t no injury can occur if there happens to be liquid R-12 in the line. If pressure is noticed when fitting is loosened, allow it to bleed off as described under discharging, adding oil, evacuating and charging procedures for C C O T A /C systems. • In the event any line is opened to atm osphere, it should be im m ediately capped or tapped to prevent entrance of m oisture and dirt which can cause internal compressor wear or plugged, lines, condenser and evaporator core, expansion tubes (orifice) or compressor inlet screens. • The use of the proper wrenches when m aking condenser and connections on "O " ring fittings is im portant. The use of im proper wrenches may dam age the connection. The opposing fitting should always be backed up with a wrench to prevent distortion of connecting lines or components. W hen connecting the flexible hose connec­ tions it is im portant th a t the swaged fitting and the flare IB -11 nut, as well as the coupling to which it is attached, be held at the same tim e using three different wrenches to prevent turning the fitting and dam aging the ground seat. • "O " rings and seats m ust be in perfect condition. A burr or piece of dirt may cause a refrigerant leak. Always replace the "O " ring when a correction has been broken. W hen replacing the " O " ring, first dip it in clean 525 viscosity refrigeration oil. • W here steel to alum inum corrections are being made, use torque for alum inum tubing (R efer to C hart 1B-9). MAINTAINING CHEMICAL STABILITY IN THE REFRIGERATION SYSTEM The efficient operation of the air conditioning refrigera­ tion system is dependent upon the pressure - tem perature relationship of pure R-12 (Refer to C hart 1B -l). As long as the system contains pure R-12 (plus a certain am ount of 525 Viscosity Compressor oil which mixes with the R-12, it is considered to be chem ically stable. W hen foreign m aterials, such as dirt, air or m oisture are allowed to get into the system, they will change the pressure - tem perature relationship of the R efrig eran t-12. Thus, the system will no longer operate a t the proper pressures and tem peratures and the efficiency will decrease. The following general practices should be observed to ensure chemical stability in the system: 1. W henever it becomes necessary to disconnect a refrig­ erant connection, wipe away any dirt or oil at and near the connection to elim inate the possibility of d irt entering the system . Both sides of the connection should be capped, plugged or taped as soon as possible to prevent the entrance of dirt, foreign m aterial and moisture. (It must be rem em bered th at all air contains moisture. A ir th at enters any part of the refrigerant system will carry m oisture with it and the exposed surfaces will collect the moisture quickly.) 2. Keep tools clean and dry. This includes the manifold gage set and replacem ent parts. 3. W hen adding 525 viscosity refrigerant oil (Refer to A D D IN G O IL in the "D ischarging, A dding Oil, Evacuating and C harging Procedures for C C O T A /C S ystem s"), the container/transfer tube through which the oil will flow should be exceptionally clean and dry due to the fact th at refrigeration oil is as moisture-free as it is possible to make it. 4. W hen it is necessary to "open" an A /C system, have everything needed ready and handy so th at as little tim e as possible will be required to perform the operation. Do not leave the A /C system open any longer than is necessary. 5. Any tim e the A /C system has been "opened," it should be properly Evacuated before recharging with R-12 according to the D IS C H A R G IN G A D D IN G O IL, E V A C U A T IN G & C H A R G IN G P R O C E D U R E S FO R C C O T A /C SY ST E M S following in the Service M anual. REFRIGERANT CHARGING PRECAUTIONS N orm ally, air conditioning systems are charged m ak­ ing use of the C harging Station J-23500-01 which uses the 13.60 kg (30 lb.) of R-12. 420 ml (14 oz.) R efrigerant-12 LIG H T T R U C K SERVICE M A N U A L IB -12 AIR CONDITIONING disposable cans or R-12 drum s are also used. D IS C H A R G ­ IN G , A D D IN G O IL , E V A C U A T IN G A N D C H A R G ­ IN G P R O C E D U R E S F O R C C O T S Y S T E M S are de­ scribed on following pages in the Service M anual. • Em pty R -12 container completely before disposing. • See Disposable Can C H A R G IN G procedures later in Service M anual. With J-23500-01 Charging Station: With R-12 Drum or 14 oz. Disposable Can Charging: • DO N O T charge while compressor system is hot. • A L W A Y S C H A R G E T H R O U G H L O W -S ID E O F A /C S Y S T E M (low -side fitting is found on accum ulator). • N E V E R C O N N E C T O N H IG H -S ID E of A /C sys­ tem or to any system having a pressure higher than indicated on the R - 12 container. « W hen opening valves designed for use with container, follow m an u factu rer’s directions carefully. • Always use pressure gages before and during C harging. • Follow m anufacturer’s directions carefully with three exceptions: • H I-P R E S S U R E V A LV E O F G A G E SE T SH O U L D BE C L O S E D A T A L L T IM E S D U R IN G C H A R G IN G • DO N O T C O N N E C T H IG H P R E S S U R E L IN E TO A /C SY ST E M • A L L E V A C U A T IN G A N D C H A R G IN G O F A /C S Y S T E M M U S T BE P E R F O R M E D T H R O U G H LO W P R E S S U R E V A L V E /L IN E T O L O W -SID E S E R V IC E F IT T IN G O N A C C U M U L A T O R DIAGNOSIS TESTING THE REFRIGERANT SYSTEM If a m alfunction in the refrigerant system is suspected due to abnorm al system pressures, check the following: 1. C heck outer surfaces of radiator and condenser cores to be sure they are not plugged with dirt, leaves or other foreign m aterial. Be sure to check between the con­ denser and radiato r as well as the outer surfaces. CAUTION:Do not use lighted detector in any place where combustible or explosive gases, dusts or vapors may be present. Operating Detector 1. D eterm ine if there is sufficient refrigerant in the system for leak testing. 2. R estrictions or kinks in evaporator core or condenser core, hoses, tubes, etc. 2. Open control valve only until a low hiss of gas is heard, then light gas at opening in chimney. 3. R efrigerant leaks. 3. A djust flame until desired volume is obtained. This is most satisfactory when blue flame is approxim ately 3/8 in. above reactor plate. The reaction plate will quickly heat to a cherry red. 4. C heck all air d u cts for leaks or restrictio ns. A ir restrictio n m ay in d icate a plugged (or p artially plugged) evaporator core. 5. Com pressor clutch slippage. 6. Im proper drive belt tension. 7. Plugged accu m u lato r, expansion tu b e (orifice) or compressor suction inlet screen. 8. Excessive m oisture in refrigerant system. 9. S ta rt properly operating, tuned engine and set up A /C system according to appropriate P E R F O R M A N C E C O N D IT IO N S stated in C C O T System Diagnostic Procedure (C h art IB-3 & IB -4). LEAK TESTING THE REFRIGERANT SYSTEM W henever a. refrigerant leak is suspected in the system or a service operation perform ed which results in disturbing lines or connections, it is advisable to test for leaks. Common sense should be used in perform ing any refrigerant leak test, since the necessity and extent of any such test will, in general, depend upon the n atu re of the com plaint and the type of service perform ed on the system. J-6084 Leak Detector Tool J-6084 is a propane gas-burning torch which is used to locate a leak in any p a rt of the system. R efrigerant gas draw n into the sam pling tube attached to the torch will cause the torch flame to change color in proportion to the size of the leak. Propane gas fuel cylinders used with the torch are readily available com m ercially throughout the country. L IG H T T R U C K SE RV IC E M A N U A L 4. Explore for leaks by moving the end of the sampling hose around possible leak points in the system. Do not pinch or kink the hose. Since R-12 is heavier than air, it is good practice to place open end of sam pling tube immediately below point being tested, particularly in cases of small leaks. CAlVTION:Do not breathe the fumes that are produced by the burning of R-12 gas in the detector flame, since such fumes can be toxic in large concentrations. 5. W atch for color changes. The color of the flame which passes through the reaction plate will change to green or yellow-green when sam pling hose draws in very small leaks of R-12. L arge leaks will be indicated by a change in color to a brilliant blue or purple; when the sampling hose passes the leaks, the flame will clear to an almost colorless pale-blue again. Observations are best m ade in a sem i-darkened area . If the flame rem ains yellow when unit is rem oved from leak, insufficient air is being drawn in or the reaction plate is dirty. A refrigerant leak in the high pressure side of the system m ay be more easily detected if the system is operated for a few m inutes, then shut off and checked im m ediately (before system pressures equalize). A leak on the low pressure side may be more easily detected after the engine has been shut off for several m inutes (system pressures equalized); this applies particularly to the front seal. PRESSURE CYCLING CCOT SYSTEM C60, C-K and G MODELS C om pressor clutch cycling on C -K & G S eries C60 C C O T A /C System s is accomplished through the use of a pressure sensing switch, (R efer to Fig. IB-21 &1B-22) located n ear the top of th e accu m u lato r. T he switch perform s two functions in the system. In addition to cycling the compressor on and off to control refrigerant flow, the switch shuts off the compressor clutch when pressure falls to a predeterm ined level, indicating low refrigerant charge in the system. W hen diagnosis (R efer to C h a rt IB-3 & IB-4) indi­ cates replacem ent of the switch is necessary, it should be noted th at it will not norm ally be necessary to discharge the A /C system, as the pressure switch fitting on the accum ula­ tor is equipped with a schrader type valve. W hen replacing the pressure cycling switch, a new oiled " O " ring m ust be installed and the switch m ust be torqued to 10 N-m (7.5 ft lb). Do not exceed this torque, as the threads in the accum ulator m ay be stripped. IB -14 AIR CONDITIONING SERVICE DIAGNOSTIC PROCEDURE INSUFFICIENT COOLING A/C SYSTEMS WITH CYCLING CLUTCH — EXPANSION TUBE (PRESSURE SENSING) M O V E T E M P LEVER R APID LY BA C K A N D FORTH FR O M H O T TO C O LD . LIS T E N FOR DOOR H IT T IN G A T EACH END C irc u m s ta n c e s S h o u ld a S ig h t G la s s Be In s ta lle d Feel L iq u id L in e B e fo re E x p a n s io n T u b e R e s tric tio n in H ig h S id e o f S y s te m . V is u a lly C heck fo r F ro s t S p o t to Lo c a te R e s tric tio n . R e p a ir as N ec e s s ary , Feel E v a p o ra to r In le t a n d O u tle t Pipes IN LE T PIPE A N D O U T LE T PIPE S A M E T EM PE R A TURE OR O U T LE T C OLDER T H A N IN LE T i I S y s te m E v a c u a te & C h a rg e In s ta ll G a g e S e t a n d C h e c k C o m p re s s o r C y c lin g Press (O.K.) O N a t 2 8 2.6-35 1.6 kPa 141-51 PSI) OFF a t 138-193 kPa (20-28 PSI) R U N S C O N T IN U O U S L Y W IT H IN L IM IT S CYCLES H IGH OR LO W (O N AB O V E 51 PSI OR OFF BE LO W 20 PSD C YC LES W IT H IN L IM IT S T --------1--------D e fe c tiv e D is c o n n e c t B lo w e r W ir e a n d C he c k For C y c lin g O ff a t 13 8-1 93 kPa (20 -2 8 PSI) P ressu re S w itc h PRESSU R E F A L LS B E L O W 20 PSI C YC LES OFF A T 138 193 kP a (20 -2 8 PSI) O R D O ES N O T P U L L D O W N TO PRESS D e fe c tiv e P re s s u re S w itc h I R ep lace *D o N o t D is c h a rg e In s ta ll T h e rm o m e te r in A/C O u tle t and C he ck P e rfo rm a n c e R ep lace . 'D o N o t D itc h a rg e S y s te m . T h e re is a S c h ra d e r V a lv e in th e F ittin g 1 2. 3. 4. 5. 6. I S y s te m (O .K .) 21°C (70° F) A M B IE N T TEMP. A/C O U T LE T TEMP. S ystem (O.K.) SET T E M P LEVER TO F U LL C O LD SET SELECTOR LEVER T O M A X A/C SET BLO W ER S W IT C H O N HI CLOSE D O O R S A N D W IN D O W S R U N EN G IN E A T 20 00 R P M USE A U X . F A N IN F R O N T OF GRILL 27° C (8 0 °F) 32° C (90°F) 38° C (100°F) 43° C (1 10°F) PICK-UP 5-8°C (41-47) 5-8°C (41-47) 6-10°C (42-50) 6 -1 1°C (43-57) 6 -1 1°C (43-51) SU B U R B A N 6-9°C (42-48) 6-9°C (42-48) 10-14°C (50-58) 12-17°C (54-62) 14-19°C (57 67) O U T LE T TE M P E R A T U R E HIGH A S PER C H AR T O U T LE T TE M P E R A T U R E W IT H IN LIM IT S S y s te m (O .K .) C he ck C o m p re s s o r C y c lin g O N C O N T IN U O U S L Y CYCLE O N A N D OFF OR R E M A IN S OFF FOR LO N G PERIOD OF T IM E ••D is c h a rg e S y s te m a n d C he c k For M is s in g E x p a n s io n T u b e D is c h a rg e S y s te m a n d C he ck fo r P lu g g e d E x p a n s io n T ub e | M IS S IN G | IN PLACE i i S y s te m I E v a c u a te & C h a rg e i_____ E v a c u a te fit C h a rg e C LE AN (O .K .) I R e p a ir o r R e p la ce S cree n S y s te m O v e r C h a rg e d I E v a cu a te & C h a rg e i S ystem E va cu a te & C h a rg e (O .K.) LIG H T T R U C K SE RV IC E M A N U A L R ep lace T C heck C o m p re s s o r In le t S cree n _____________ In s ta ll E x p a n s io n T u b e I S ystem (O K .) S ys te m (O .K.) AIR CONDITIONING IB -15 SERVICE DIAGNOSTIC PROCEDURE INSUFFICIENT COOLING A/C SYSTEMS WITH CYCLING CLUTCH — EXPANSION TUBE (PRESSURE SENSING) M O V E T E M P LEVER R APID LY B A C K A N D FORTH FR O M H O T T O C O L D . LIS T E N FOR D O O R H IT T IN G A T EACH END T h is S y s te m D oe s N o t H ave a S ig h t G lass. U n d e r N o C irc u m s ta n c e s S h o u ld a S ig h t G lass Be In s ta lle d F eel L iq u id L in e B e fo re E x p a n s io n T u b e R e s tric tio n in H ig h S id e o f S y s te m . V is u a lly C heck fo r F ro s t S p o t to Lo c a te R e s tric tio n . R e p a ir as N ec e s s ary . Feel E v a p o ra to r In le t a n d O u tle t P ip es IN LE T PIPE A N D O U T LE T PIPE S A M E T E M P E R A ­ TU RE OR O U T LE T COLD ER T H A N IN LE T I I S y s te m E v a c u a te & C h a rg e In s ta ll G a ge S e t a n d C h e c k C o m p re s s o r C y c lin g Press, (O .K.) i O N a t 2 8 2 .6-35 1.6 kPa (41-51 PSI) OFF a t 138-193 kPa (20-28 PSI) R U N S C O N T IN U O U S L Y W IT H IN L IM IT S | C YC LES W IT H IN L IM IT S CYCLES H IG H OR LO W (ON A B O V E 51 PSI OR OFF B E LO W 20 PSI) | T D is c o n n e c t B lo w e r W ir e a n d C he c k F or C y c lin g O ff a t 13 8-1 93 kPa (20 -2 8 PSI) P R ESSU R E FALLS B E L O W 20 PSI D e fe c tiv e P re ssu re S w itc h CYCLES OFF A T 138-193 kP a (20 -2 8 PSI) OR D O ES N O T PU LL D O W N TO PRESS D e fe c tiv e P re s s u re S w itc h I R ep lace •D o N o t D is c h a rg e S y s te m , T h e re In s ta ll T h e rm o m e te r in A/C O u tle t an d C he ck P e rfo rm a n c e R eplace. ’ D o N o t D is c h a rg e S y s te m . T h e re is a S c h ra d e r V a lv e in th e F ittin g 1. 2. 3. 4. 5. 6. I S ystem (O .K.) A M B IE N T TEMP. A /C O U T LE T TEMP. S yste m (O .K.) SET T E M P LEVER TO F U LL C O LD SET SELECTOR LEVER TO M A X A/C SET B LO W E R S W IT C H O N HI CLOSE D O O R S A N D W IN D O W S R U N EN G IN E A T 2000 R .P.M U SE A U X . F A N IN F R O N T OF G R ILL 21°C (70° F) 27° C (80 °F) 32° C (9 0 °F) 38° C (100° F ) 43° C ( 1 10°F) PICK-UP 5-8°C (41-47) 5-8°C (41-47) 6-10°C (42-50) 6-1 f C (43-57) 6 -1 1°C (43-51) S U BU R BA N 6-9°C (42-48) 6-9°C (42-48) 10-14°C (50-58) 12-17°C (54-62) 14-19°C (57-67) O U T LE T TE M P E R A T U R E H IG H A S PER C H AR T O U T LE T TE M P E R A T U R E W IT H IN L IM IT S T S y s te m (O .K.) C he ck C o m p re s s o r C y c lin g O N C O N T IN U O U S L Y CYCLE O N A N D OFF OR R E M A IN S OFF FOR LO N G PERIOD OF T IM E ------------------------f ----------------------- ’ •D is c h a rg e S y s te m a n d C he ck For M is s in g E x p a n s io n T u b e D is c h a rg e S y s te m a n d C heck fo r P lu g g e d E x p a n s io n T ub e i i E v a c u a te & C h a rg e i S yste m R ep lace In s ta ll E x p a n s io n T u b e C he ck C o m p re s s o r In le t S cree n i E v a c u a te & C h a rg e S y s te m (O .K.) (O .K.) P LU G G E D R ep air o r R ep lace S cree n I i S ystem E v a cu a te & C h a rg e (O .K.) S y s te m O v e r C h a rg e d I E v a cu a te & C h a rg e S ystem (O .K.) L IG H T T R U C K SERVICE M A N U A L IB-16 AIR CONDITIONING ELECTRICAL/VACUUM TROUBLE DIAGNOSIS W hen diagnosing problem s in the electrical and vac­ uum systems of the air conditioning system, consult electri­ cal wiring diagram s and vacuum diagram s. Ports on rotary vacuum valves are illustrated in a m anner to provide sim plicity in following vacuum schem atic lines but are num bered in consecutive order on the actual valve. Operational Test To aid in determ ining w hether or not the air condition­ ing electrical, air, vacuum and refrigeration systems are operating properly and efficiently, refer to C h art IB-3. 1. O peration of the air conditioning blower at all four speeds and engagem ent of the compressor clutch would indicate th a t electrical circu its are functioning properly. 2. The same hand-felt tem perature of the evaporator inlet pipe and the accum ulator can surface of an operating system would indicate a properly charged R -12 system. 3. O peration of the A /C control selector (mode) lever to d istrib u te air from designed outlets would indicate proper vacuum and diaphragm function. VACUUM SYSTEM DIAGNOSIS C-K and G, C60 SYSTEM S ta rt the engine and allow it to idle - move the selector lever to each position and refer to the vacuum diagram s and operational charts for proper airflow, air door functioning and vacuum circuits. If air flow is not out of the proper outlets a t each selector lever position, then proceed as follows: 1. C heck for good hose connections—a t th e vacuum actuators, control head valve, reservoir, tees, etc. 2. Check the vacuum source circuit as follows: Install vacuum tee and gage (with restrictor) at the vacuum tank outlet (R efer to V acuum D iagram ). Idle the engine and read the vacuum (a normal vacuum is equivalent to manifold vacuum ) a t all selector lever positions. a. Vacuum Less T han N orm al A t All Positions Remove the tee and connect the vacuum gage line directly to the tank - read the vacuum . If still low, then the problem lies in the feed circuit, the feed circuit to the tan k or in the tank itself. If vacuum is now norm al, then the problem lies downstream . b. Vacuum Less T han N orm al at Some Positions. If vacuum was low at one or several of the selector lever positions, a leak is indicated in these circuits. LIG H T T R U C K SE RV IC E M A N U A L c. Vacuum N orm al at All Positions; If vacuum was norm al and even at all positions, then the m alfunction is probably caused by improperly connected or plugged lines or a defective vacuum valve or valves. 3. Specific Vacuum C ircuit Check Place the selector lever in the m alfunctioning position and check for vacuum at the pertinent vacuum actua­ tors. If vacuum exists at the actuator but the door does not move, then the actuator is defective or the door is m echanically bound. If low or no vacuum exists at the actuator, then the next step is to determ ine w hether the cause is the vacuum harness or the vacuum valve. Check the vacuum harness first. 4. Vacuum H arness C ircuit Check a. Disconnect the vacuum harness at the control head. b. The black line ( # 1 ) should show engine vacuum - if not, trace back through connector to vacuum tank. c. To check any individual circuit place the selector lever at the involved circuit position and check for vacuum presence. VACUUM AND WIRING DIAGRAMS Refer to Fig. 1B -14 thru 1B-22. COMPRESSOR DIAGNOSIS Check for proper air gap. CLUTCH SLIPPING. Correct if necessary. (.022-.057) CO M PRESSO R E N G A G ED If previous step does not correct clutch slippage, repair compressor. B U T N O T O P E R A T IO N A L BELT SLIPPING. Check and correct belt tension. HIGH TORQUE COMPRESSOR. (SEIZED) REFRIGERATION CHARGE IS DEPLETED. SYSTEM HAS SOME REFRIGERANT. LEAKS R E F R IG E R A N T . Add one pound refrigerant. Leak test complete system before removing compressor. Repair compressor. Operate and leak test system. Repair compressor. Blow out seal cavity CO M PRESSO R T H R O W S O IL . with air hose and leak test. D O E S NOT L E A K Wipe off oil - O.K. NOISY ONLY WHEN CLUTCH IS ENGAGED. LIGHT TRUCK A/C system noise is to be evaluated in the vehicle w ith doors and windows closed and low blower on. NOISY WHEN CLUTCH IS NOT ENGAGED. parts. Isolate and re-evaluate noise. Remove compressor belt to determine if noise still persists. Check and adjust belt tension. Check for interference between coil housing and pulley hub. Repair compressor if noise is objectionable. If interference exists, repair compressor. AIR CONDITIONING NOTE: Check for refrigerant lines touching metal SERVICE IB -1 7 MANUAL TRUCK IB -18 LIGHT INSUFFICIEN T COOLING D IA G N O S IS CHART DASH MOUNTED UNIT (MOTOR HOME CHASSIS UNITS) M ANUAL 4. Check for broken, burst, or cut hoses. Also check for loose fittings on all components. N O R M A L A IR FLO W j CHECK 5. 6. 7. 8. 9. Check Check Check Check Install for condenser air blockage due to foreign material. for proper air ducting hose connections. heater temperature door adjustment, adjust if incorrect. evaporator sealing for air leak, repair if leaking. pressure gages and thermometer and make performance test. C H E C K A IR FLO W NO O R LO W A I R F L O W C H E C K B L O W E R O P E R A T IO N D IS C H A R G E A I R T E M P E R A T U R E (S E E P E R F O R M A N C E D A T A ) | B L O W E R N O T O P E R A T IN G N O R M A L B L O W E R O P E R A T IO N I D IS C H A R G E T E M P E R A T U R E A T O U T LET COLD C H E C K F O R B L O W N F U S E , D E F E C T IV E B L O W E R SW IT C H , H IG H O U T L E T A IR TEM PERATU RE CHECK FOR A IR LE A K S TH R O U G H D ASH PA N E L. DOORS, WINDOW S, OR FROM H EA TE R . Check for loose or disconnected air distribution ducts, restricted or leaking air ducts, partially closed air out­ let valve or clogged evaporator core, if above check is O K, check for ice blocking evaporator. B R O K E N W IR E . L O O S E C O N N E C T IO N S , L O O S E B L O W E R M O T O R G R O U N D W IR E O R I N O P E R A T IV E B L O W E R M O T O R . C H E C K S IG H T G L A S S IC E B L O C K IN G EVAPO RATOR |'f o a m i n g | " SYSTEM NO F O A M IN G IS P R O B A B L Y L O W O N R E F R IG E R A N T . C H E C K F O R L E A K S . R E P A IR , A N D A D D R E F R IG E R A N T . IF F O A M IN G S T I L L O C C U R S , C H E C K F O R R E S T R IC T IO N IN R E F R I G E R A N T S Y S T E M B E T W E E N C O N D E N S E R A N O S IG H T G LA SS. C H EC K FO R LOW E V A P O R A T O R P R E SSU R E 1. A L L O W S Y S T E M T O W A R M UP. 2. S T O P A N D R E S T A R T E N G IN E . 3. C H E C K E V A P O R A T O R P R E S S U R E IM M E D IA T E L Y A F T E R R E S T A R T A N O PU LL DOW N OF E V A P O R A T O R PR ESSU R E. 1. S Y S T E M M A Y B E E IT H E R F U L L Y C H A R G E D O R E M P T Y . F E E L H IG H A N D L O W P R E S S U R E P IP E S A T C O M P R E S S O R . H IG H P R E S S U R E P IP E S H O U L D B E W A R M . L O W P R E S S U R E P IP E S S H O U L D B E C O L D . 2. IF P IP E S A R E N O T IN D IC A T IN G P R O P E R T E M P E R A T U R E S , R E C H A R G E S Y S T E M A S R E C O M M E N D E D . IF N O Z Z L E A IR T E M P E R A T U R E IS S T IL L H IG H . C H E C K E V A P O R A T O R PRESSU RE. NO RM AL EVAPO RATO R PRESSU RE X LOW E V A P O R A T O R •PRESSU RE *C H E C K E V A P O R A T O R P R E S S U R E Z= 1 , , B Y R E M O V IN G V A L V E A N D B L O W IN G T H R O U G H V A L V E . IF U N A B L E T O B L O W T H R O U G H V A L V E , B U L B IS D IS C H A R G E D . R E P L A C E E X P A N S IO N VALVE. Check for m alfunctioning expansion valve-See C om ponent Diagnosis. Check for m alfunctioning expansion valve-See Com ponent Diagnosis. NORMAL X L O W D IS C H A R G E * PR ESSU RE ---- EVAPO RATO R PRESSU RE C H E C K C O M P R E S S O R D IS C H A R G E P R E S S U R E 1. C H E C K F O R L IQ U ID L IN E R E S T R IC T IO N ( F R O S T S P O T O N L IN E ). IF NO T, 2. C H E C K F O R P L U G G E D IN L E T S C R E E N IN E X P A N S IO N V A L V E . IF N O T , 3. C H E C K F O R D E F E C T IV E E X P A N S IO N V A L V E 1------T I S Y S T E M H A S E X C E S S M O IS T U R E . R E P L A C E R E C E I V E R D E H Y D R A T O R AND EV A C U A T E TH O RO U G H LY . R E C H A R G E SY STEM . H IG H E V A P O R A T O R * P R ESSU RE C H E C K E V A P O R A T O R O U T L E T L IN E EV A PO RA T O R OUTLET L IN E W A R M ~ LOW E V A P O R A T O R * PR ESSU RE I | Check Compressor Discharge Pressure. ,----- =3------------------| H IG H D IS C H A R G E P R E S S U R E I 1. Check engine cooling system, fan clutch and check for restricted air flow thru condenser. 2. Check expansion valve bulb contact. Correct if necessary. 3. Check for refrigerant restriction in condenser. Return bends at equal elevation should be approximately same temperature. If temperature of bends is appreciably different, the cooler bend indicates a restricted circuit, replace con­ denser if restriction is found, If condenser is O K, check for air in system. T o check observe outlet air temperature and com pressor discharge pressure while slowly discharging system at receiver inlet connection. L O W D IS C H A R G E P R E S S U R E ! N O R M A L D IS C H A R G E P R E S S U R E X Check for restriction in liquid line, partially plugged inlet screen at expansion valve, or defective expansion valve, replace valve if defective. JL Refrigeration System is ok 1. Check for proper function of heater T E M P E R A T U R E door. 2. Check for proper sealing of evaporator case. 3. Check for proper operation and seal around temperature door. 4. N on-Foam ing sight glass does not always indicate a fully charged system. A d d 1/2 lb. refrigerant and observe performance. 5. Check for excess oil in system. A sym ptom of excess oil is a slipping clutch or belt or broken belt. T o remove excess oil in system see " C H E C K I N G C H A R G E ". D ash M o u n te d U n i t ( M o t o r H o m e C ha ssis) O U T L E T A IR T E M P E R A T U R E D R O PS A S C O M PRESSO R D IS C H A R G E P R E S S U R E D R O P S O U T L E T A IR T E M P E R A T U R E IN C R E A S E S A S C O M P I " " ? R D IS C H A R G E P R E S S U R E D R O P S L E A K T E S T S Y S T E M , R E P A IR A S N E C E S S A R Y . D IS C H A R G E . R E P L A C E E X P A N S IO N V A L V E EVACUATE. AN O RECHARG E. O IL (R e frig e ra n t C ha rge — 3 lb s.-4 o z .) T e m p e ra tu re o f A ir E n te rin g C o n d e n se r • R E F E R TO P E R F O R M A N C E C H A RT FO R C O R REC T PR ESSU RES CO M P RESSO R 70° 80° 90° 110120 13 5 MS 160170 E ngine rpm C o m pre ssor H ead Pressure* 110° 120° 190200 22 0 230 260270 10 10 13 4247 4449 4449 200 0 Pressure psi* D ischarge A ir . T e m p e ra tu re * 100° 4045 4146 4146 *Ju st p rio r to c o m p re sso r c lu tc h dise n g ag e m e n t. AIR CONDITIONING SERVICE The follow ing procedures should be applied before performance testing an A/C System. 1. Check for proper belt installation and tension with J-23600. 2. Check for proper clutch coil terminal connector installation. 3. Check for clutch air Gap (.022 • .057). ELECTRICAL SYSTEM DIAGNOSTIC CHART BLOWER MOTOR INOPERATIVE (CERTAIN SPEEDS-EXCEPT HIGH ON C-K FOUR-SEASON) B L O W E R M O T O R IN O P E R A T IV E (A N Y S P E E D ) Check for proper fuse I fu se q k | 1 F U SE B L O W N ! Disconnect resistor connectors, connect one lead of a self powered test light to any one terminal and use the other lead to probe each of the other terminals. The following tests should be made with the ignition switch in " R u n " With ign. switch in " R u n " position and heater or A /C on, locate short in one of the following wires: (see note) position, heater or A /C on and blower switch on high. ---- I Check blower motor ground X 1. From fuse panel to master switch on control. 2. From master switch to compressor clutch. 3. Master switch to blower switch. 4. From blower speed switch to resistor. 5. From resistor to blower motor. I poor or no g r o u n d | Repair ground Iground ok I T E S T L IG H T D O E S N O T Check motor connector with 12 volt test light. | L A M P L IG H T S ! T E S T L IG H T L IG H T S ON L IG H T O N A L L T E R M I N A L S A L L T E R M IN A L S X Replace resistor With ignition switch in "R u n " position and heater or A/C on, use 12 volt test lamp to check for voltage at resistor connector w ith blower speed switch in each position. [ L A M P D O E S N O T L IG H T j X Check wire connector on Replace motor blower relay with 12 volt test light. ( l a m p L IG H T S IN a l l p o s i t i o n s | L A M P D O E S N O T L IG H T IN A L L P O S IT IO N S I .......- t ____ ( l a m p l ig h t s ! NOTE: Short circuit may be inter­ m ittent. If tester does not indicate a short circuit, move heater harness around as much as possible to re­ create short circuit. Watch and listen fo r arcing. Repair open in wire from blower motor to blower | L A M P D O E S N O T L IG H T j Check wire connector on blower relay with 12 volt test light. X relay. |L A M P L IG H T S p L A M P D O E S N O T L IG H T ] Use 12 volt test light and check wire terminals at resistor. I L A M P L IG H T S ! Replace relay X LAM P OFF L A M P L IG H T S resistor to blower speed switch. LIGHT TRUCK [L A M P 0 FFJ T SERVICE Replace blower speed switch. Replace resistor 1 1 (LAM P - ....... Replace blower relay. D O E S N O T L IG H T ! X Turn ignition key o ff and put Heater or A/C Control in o ff position. With blower resistor wire connector disconnected, connect a jumper lead from battery positive terminal to the wire terminal in connector. Use 12 vo lt test light to check fo r voltage at wire at blower speed switch connector. Repeat same test on the other wires. Repair Open in wire X from resistor to blower relay. LAMP LIGHTS ON A L L WIRES LAMP DOES NOT LIGH T ON A L L WIRES Replace blower speed switch. affected wire. Repair open in AIR CONDITIONING Check F E E D wire from |l a m p 0 n | Connect 12 volt test light at wire terminal on blower relay (wire from resistor to blower relay). Repair open in wire from blower speed switch. IB -19 M ANUAL IB-20 AIR CONDITIONING CHANGE IN AIR FLOW 1 LITTLE OR NO CHANGE IN AIR FLOW ......... NORMAL AIR FLOW | LOW OR NO AIR FLOW | I Check heater outlet temperature w ith 220° F range thermometer. Check shutoff door position for full system air flow. Adjust if necessary. (approximate outlet air temperatures) Outlet Air Ambient Air 0 150 25 155 40 75 LOW AIR FLOW | | NO AIR FLOW | CHECK FUSE NORMAL TEMPERATURE Check heater outlet for obstruction - re­ move. Remove all obstructions under fro n t seat. Car does not build up heat - operate vent controls and see that the air vent doors close completely, if not, adjust. LOW TEMPERATURE (Check the system temperature after re­ pairing the item checked to complete the diagnosis.) Check coolant level; if low, fill. Look for or feel all radiator and heater hoses and connections for leaks. Repair or replace. Check the radiator cap for damage and re­ place if required. Check motor voltage at closest motor line connection with a voltmeter. Al R FLOW - system okay. UNDER 10 VOLTS | | OVER 10 VOLTS Check battery volts - under 10 volts, recharge then recheck motor voltage. Check wiring and connections for under 10 volts from motor to fan switch. Repair or replace last point of under 10 volt reading. Check heater and radiator hoses for kinks straighten and replace as necessary. Check temperature door for max heat po­ sition. Adjust if necessary. ....................... I------------------ FUSE BLOWN - replace fuse. BLOWS FUSE Remove positive lead from motor and replace fuse. FUSE REMAINS OK - remove motor and check for obstruction in system opening, if none, REPLACE MOTOR. If obstruction, remove material and re-install motor. BLOWS FUSE - check for shorted wire in blower electric circuit See Heater Circuit Diagnostic Chart. Apply external ground, (jumper wire) to motor case. INCREASED AIR FLO W repair ground. [ HEATER CORE [ Feel temperatures of heater inlet and outlet hoses. WARM INLET AND OUTLET HOSES Check engine thermostat. HOT INLET AND WARM OUTLET HOSES Check pulleys, belt tension, etc., fo r pro­ per operation. Replace or service as neces­ sary. Remove hoses from heater core. Reverse flush w ith tap water. If plugged, repair or replace. L IG H T T R U C K SE R V IC E M A N U A L SAME AIR FLOW - remove motor and check for obstruction in system open­ ing. If none, REPLACE MOTOR. If obstruction, remove material and re­ install motor. FUSE OK - See Heater Circuit Diagnostic Chart. AIR CONDITIONING IB-21 S H E E T M E T A L « m _ ., - BLK— H g \ Q BLCWER MOTOR (2004627 SEE NOTE A £ r\ S T BLOWER RELAY RESISTOR •I LT GRN-6 6 B I D K G R N -5 9 ■£ BLK-150---- [3 1 — 5 RED-2 (S I — I DK ASM ■iCRD -£ -1 -I - I -I B L U -IO I | } - . 8 0 R N - 5 2 ------ ORN-52-------TAN-63-------BRI'VWHT-646LT BLU-72----LTGRN-66A— ---------1BRN/WHT-648, '- I 0RN(WH>64A'^ & ORN-52-) TAN-63 — -I LT BLU-72- BLOWER SWfTCH -5 PPL- 6 5 29649H -5 RED-2 - COMPRESSOR 12004268 - j MOUNTNG BLK-I50C XSXLHSl!BRACKET GND i ->5 LT G RN(SXU------- E S FAST ID L E SOLENOID DK GRN-59$XL) -I BRN/WHT-64A1 LTGRN-66AI BRN-50 ----- NOTE: * l USE WITH 12010191 SELECTOR SWITCH RETAINER AIR CONDITIONING R P 0C -60 Fig. 1B-14--C60 System W iring Diagram (C-K Series) i iLK-l50E(SXL) S E [ S S — 2BRN-C I \ A —6917585 ' ---- §917580 1-------- 2 BRN VP HARN ACC FUSED 2 0 A AIR CONDITIONING RP.Q-C60 Fig. 1B-15--C60 System Wiring Diagram (G Series) LIG H T T R U C K SERVICE M A N U A L IB-22 AIR CONDITIONING REAR BLOWER WESISTgR 2 )t i - w m -12004752 GROMMET 7541 •9175422 LT BLIV6LK-872 >— 2 YEL/BLK-851-2 0RI►/ blk - i8 5 2 MNI-C6Q- W MC. -2LTBLIVBLK -2YEU/BLK---- [•Ml ( Ml -2 OR^BLK— i-w- ii-r-i KO HO •2 LT BLLVBLK-872 — i - 2 YEL^LK-851 — - 2 QRN/BLK-852A -30R IVB LK -852B -1 -2 B R N -5 0 — ■ - 2 B R N -5 0 - hi SEAR BLOWER MOTOR SHEET METAL 3 BRfVW HT-850 GRD REAR A/C SWITCH •8917580* 8 9 I7683 5 ORH^BLK-852- L - 30RNfeLK-852B 891758 -2 B R N -50 2 BRN INST PNL HARM FUSED 25AMP 12004493 RPQ-C60j WR& i REF: -2 B R N -50H FUSE BLOCK Fig. 1 B-16--Overhead Systems Wiring Diagrams-AII L IG H T T R U C K SE RV IC E M A N U A L SELECTOR CONTROL R P 0-C 60 Fig. 1B-17--C60 System Vacuum Diagram (C-K Series) AIR CONDITIONING IB-23 IB -24 AIR CONDITIONING Fig. 1B-18--C60 System Vacuum Diagram (G Series) L IG H T T R U C K SE RV IC E M A N U A L HI I TO FUSE PANEL ||l G RO U N D Fig. 1B-19--C60 Motor Home Chassis Wiring COM PRESSOR Z ctr O RESISTOR. BLOWER M OTOR I 101 16 DK BLU 1 I• J ft ■52 16 DK BLU ■72 16 LT BLU' BLOWER SWITCH — 51 16 YEL SET AT Diagram B LO W E R -E V A P O R A T O R ASSEMBLY N TO N O N E LOW N TO 1 & 2 MED N TO 1 & 4 HIGH N TO 1, 3 & 4 AIR CONDITIONING THERMOSTATIC SWITCH BLOWER SWITCH CONNECTIO N OFF IB-25 IB-26 AIR CONDITIONING Fig. 1B-20--I.P. A /C Harness Wiring L IG H T T R U C K SE RV IC E M A N U A L AIR CONDITIONING IB-27 LIG H T T R U C K SERVICE M A N U A L IB-28 AIR CONDITIONING INSUFFICIENT COOLING "QUICK-CHECK" PROCEDURE The following C C O T "H an d -F eel" procedure can be used to quickly determ ine w hether or not the A /C system has the proper charge of R-12 (providing am bient tem pera­ ture is above 70°F (21°C ). This check can be m ade in a m atter of m inutes, simplifying system diagnosis by pinpoint­ ing the problem to the am ount of R-12 charge in the system or by elim inating this possibility from the over-all checkout. 1. E ngine m ust be w arm (C H O K E O P E N and O F F FA ST ID L E SPE E D C A M ). 2. Hood and body doors open. 3. Selector lever set at N O R M . 4. T em perature lever a t CO LD . 5. Blower on H I. 6. N orm al engine idle. 7. " H a n d -F e e l" te m p e ra tu re of evaporator inlet pipe A N D accu m u lato r can su rface w ith com pressor engaged. a. B O T H S A M E T E M P E R A T U R E A N D S O M E D E G R E E C O O L E R T H A N A M B IE N T -P ro p e r condition: check for other problems (R efer to A /C System Diagnostic Procedure). b. IN L E T P IP E C O O L E R than accum ulator surface low refrigerant charge. • Add slight am ounts 120 ml (1 /4 lb.) of refrigerant U N T IL B O TH feel the sam e tem perature. Allow stabilization tim e between additions. • T hen add 420 ml (14 oz.) (1 can) ad ditional refrigerant. c. IN L E T P IP E H A S F R O S T A C C U M U L A T IO N A ccum ulator surface w arm er; proceed as stated in Step b. SPECIFIC COMPONENT DIAGNOSIS The following is a description of the type of symptom each refrigerant com ponent will evidence if a defect occurs: COMPRESSOR A compressor defect will appear in one of four ways: Noise, seizure, leakage, or low discharge pressure. NOTICE: Resonant com pressor noises are not cause for alarm ; however, irregular noise or rattles m ay indicate broken parts or excessive clearances due to wear. To check seizure, de-energize the m agnetic clutch and check to see if drive plate can be rotated. If rotation is im possible, com pressor is seized (R efer to "F alse Compressor S eizu re"). To check for a leak, refer to leak testing. Low discharge pressure may be due to a faulty internal seal of the compressor, or a restriction in the compressor. Furtherm ore, low discharge pressure m ay be due to an insufficient refrigerant charge or a restriction elsewhere LIG H T T R U C K SE RV IC E M A N U A L in the system. These possibilities should be checked prior to servicing the compressor. If the compressor is inoperative, but is not seized, check to see if current is being supplied to the m agnetic clutch coil term inals. CONDENSER A condenser may be defective in two ways: it may leak, or it may be restricted. A condenser restriction will result in excessive compressor discharge pressure. If a partial restric­ tion is present, sometimes ice or frost will form immediately after the restriction as the refrigerant expands after passing through the restriction. If air flow through the condenser or radiator is blocked, high discharge pressures will result. D uring normal condenser operation, the outlet pipe will be slightly cooler than the inlet pipe. RECEIVER-DEHYDRATOR - MOTOR HOME CHASSIS A defective receiver-dehydrator m ay be due to a restriction inside the body of the unit. A restriction at the inlet to the receiver-dehydrator will cause high head pressures. O utlet tube restrictions will be indicated by low head pressures and little or no cooling. An excessively cold receiver-dehydrator outlet may be indicative of a restriction. EXPANSION VALVE A m alfunction of the expansion valve will be caused by one of the following conditions: valve stuck open, valve stuck closed, broken power element, a restricted screen or an improperly located or installed power elem ent bulb. The first three conditions require valve replacem ent. The last two may be corrected by replacing the valve inlet screen and by properly installing the power elem ent bulb. A ttachm ent of the expansion valve bulb to the evapora­ tor outlet line is very critical. The bulb must be attached tightly to the line and must make good contact with the line along the entire length of the bulb. A loose bulb will result in high low side pressures and poor cooling. Indications of expansion valve trouble are provided by perform ance tests; consult diagnostic charts. VALVE ST U C K O PE N Noisy Compressor N o Cooling - Freeze Up. VALVE ST U C K C L O SE D , BR O K EN PO W ER E L E M E N T O R PL U G G E D S C R E E N Very Low Suction Pressure. N o Cooling. PO O R L Y LO C A TED PO W E R E L E M E N T BULB N orm al Pressure. Poor Cooling. Diagnosis for Defective Valve The following procedure must be followed to determ ine if a m alfunction is due to a defective expansion valve. 1. Check to determ ine if the system will m eet the per­ form ance test as outlined previously. If the expansion valve is defective, the low pressure readings (evaporator pressure) will be above specifications. 2. The loss of system perform ance is not as evident when the compressor head pressure is below 1 379 kPa (200 psi). Therefore, it may be necessary to increase the AIR CONDITIONING system head pressure by partially blocking the con­ denser. Disconnect the blower lead wire and repeat the "perform ance check" to determ ine if the evaporator pressure can be obtained. 3. The system will also indicate a low refrigerant charge by bubbles occurring in the sight glass (M otor Home Chassis System s). EVAPORATOR W hen the evaporator is defective, the trouble will show up as an inadequate supply of cool air. A partially plugged core due to dirt, a cracked case, or a leaking seal will generally be the cause. REFRIGERANT LINE RESTRICTIONS Restrictions in the refrigerant lines will be indicated as follows: 1. Suction Line - A restricted suction line will cause low suction pressu re a t th e com pressor, low discharge pressure and little or no cooling. 2. D ischarge Line - A restriction in the discharge line generally will cause the pressure relief valve to open. 3. Liquid Line - A liquid line restriction will be evidenced by low discharge and suction pressure, and insufficient cooling. IB-29 Sight Glass Diagnosis (Motor Home Chassis Units) At tem peratures higher than 70°F (21°C), the sight glass may indicate wheter the refrigerant charge is suffi­ cient. A shortage of liquid refrigerant is indicated after above five m inutes of compressor operation by the appear­ ance of slow-moving bubbles (vapor) or a broken column of refrigerant under the glass. Continuous bubbles may appear in a properly charged system on a cool day. This is a normal situation. If the sight glass is generally clear and perform ­ ance is satisfacto ry , occasional bubbles do not indicate refrigerant shortage. If th e sight glass consistently shows foam ing or a broken liquid column, it should be observed after partially blocking the air to the condenser. If under this condition the sight glass clears and the perform ance is otherwise satisfac­ tory, the charge shall be considered adequate. In all instances where the indications of refrigerant shortage continues, additional refrigerant should be added in 120 ml (1 /4 lb.) increm ents until the sight glass is clear. An additional charge of 240 ml (1 /2 lb.) should be added as a reserve after the glass clears. In no case should the system be overcharged. ON VEHICLE SERVICE EVACUATING AND CHARGING PROCEDURES PRECAUTIONARY SERVICE MEASURES Before any service is attem pted which requires opening of refrigerant lines or com ponents, the person doing the work should be thoroughly fam iliar with the inform ation under P R E C A U T IO N S IN H A N D L IN G R E F R IG E R ­ A N T -12, P R E C A U T IO N S IN H A N D L IN G R E F R IG ­ E R A N T L IN E S A N D F IT T IN G S M A IN T A IN IN G C H E M IC A L S T A B IL IT Y IN T H E R E F R IG E R A T IO N S Y S T E M , A N D R E F R IG E R A N T C H A R G IN G P R E ­ C A U T IO N S and should follow very carefully the D IS ­ C H A R G IN G , E V A C U A T IN G , O IL A D D IT IO N A N D C H A R G IN G T H E R E F R IG E R A N T S Y ST E M instruc­ tions given on th e following pages for the unit being serviced. M ake sure fittings are dry prior to reassembly. If dirt, grease or moisture get inside pipes and cannot be removed, the pipe should be replaced. Sealing caps should be removed from subassemblies ju st prior to making connections for final assembly. Use a small am ount of clean 525 viscosity refrigerant oil on all tube and hose joints. Always use new "O " rings dipped in the clean refrigerant oil when assembling joints. The oil will aid in assembly and help provide a leak-proof joint. W hen tightening joints, use a second wrench to hold stationary part of connection so th at a solid feel can be attained. This will indicate proper assembly. NOTICE: Tighten all tubing connections as torque chart (C hart IB-9). Insufficient or torque when tightening can result in loose deformed joint parts. Either condition can refrigerant leakage. T he m ajor reasons behind these m easures are safety and the prevention of d irt and m oisture in the system which can restrict A /C system refrigerant flow. The presence of m oisture can also cause the form ation of hydrochloric or hydrofluoric acids in the system. All subassem blies are dehydrated and sealed prior to shipping. T hey are to rem ain sealed until ju st prior to making connections. All subassemblies should be at room tem perature before uncapping (this prevents condensation of m oisture from the air th a t enters the system ). If, for any reason, caps are removed but the connections are not made, parts should be resealed as soon as possible. All precautions should be taken to prevent dam age to fittings or connections. A ny fittings getting grease or dirt on them should be wiped clean with a cloth dam pened with Stoddard solvent, kerosene (or equivalent) m ay be used. shown in excessive joints or result in CCOT REFRIGERANT OIL DISTRIBUTION A-6 C O M P R E S S O R SY STEM - requires 300 ml (10 oz.) of 525 viscosity oil. R-4 C O M P R E S S O R SY ST E M - requires 180 ml (6 oz.) of 525 viscosity oil. New oil quantities m ust be added to the system during Service component replacem ent and conditions stated as follows: A. W hen there are no signs of excessive oil leakage, for the LIG H T T R U C K SERVICE M A N U A L IB-30 AIR CONDITIONING M ETAL TUBE TH R EA D AN D OUTSIDE F ITTIN G SIZE DIA M ETER 1/4 3/8 1/2 5/8 3/4 STEEL TU BING TO RQ UE LB, FT. Nm LB. FT. Nm 10-15 30-35 30-35 30-35 30-35 14-20 41-48 4148 41-48 4148 5-7 11-13 15-20 21-27 28-33 7-9 15-18 20-27 29-37 3845 7/16 5/8 3/4 .. A L U M IN U M OR COPPER N O M IN A L TUBING TORQUE TORQUE WRENCH SPAN . m ...... . 1 1/16 5/8 3/4 7/8 1 1/16 . liilJ • Com pressor - Remove, drain oil, m easure, replace same am ount of new oil plus 30 ml (1 oz.). • Evaporator - A dd 90 ml (3 oz.). • Condenser - A dd 30 ml (1 oz.). • A ccum ulator - Remove, drain oil, m easure, replace same am ount of new oil plus 30 ml (1 oz.) to compen­ sate for th a t re ta in e d by the original accu m u lato r dessicant. B. W ith signs of excessive oil leakage, for A-6 Compressor Systems Remove Com pressor A N D A ccum ulator. D rain, m ea­ sure and record T O T A L oil from both components. Discard old oil. If less than 180 ml (6 oz.), add 6 oz. of new oil to system. If m ore th an 180 ml (6 oz.), add sam e am ount of new oil as drained. If a new accum ulator m ust be added to A-6 system, add 1 additio n al ounce of oil to com pensate for th a t held / absorbed by the original accum ulator dessicant. For A-6 & R-4 Compressor System s - Condenser - 30 ml (1 oz.). For R -4 Com pressor S ystem only - A ccu m ulator (D rain oil, measure, replace sam e am ount plus 30 ml- 1 oz.). For A -6 C om pressor S ystem only - A ccu m ulator (R efer to Item 2 below). 2. However, on an A-6 compressor system: • ? I f either the accum ulator or the compressor is to be replaced. •? O r if there are signs of abundant oil leakage. T H E N BO TH A C C U M U L A T O R A N D C O M ­ P R E S S O R m ust be removed, oil drained, and m easured to determ ine correct q u an tity of oil replacem ent for the system. If the am ount of oil recovered is 120 ml (4 oz.) or more, replace with a like am ount of new oil. If less than 120 ml (4 oz.) are recovered, add 180 ml (6 oz.) of new oil. A good A-6 system will have 180 ml (6 oz.) of oil found in the accum ulator an d/or compressor. N either necessarily has 90 ml (3 oz.) - could be more or less. This is why BOTH have to be m easured. • ? I N A D D IT IO N to these m easure am ounts, one (1) additional fluid ounce M U ST be added to replace that am ount captured in the oil desiccant of the replaced accum ulator assembly. New service A-6 Compressors are shipped with 300 ml (10 oz.) of oil already inside. Therefore, when a new A-6 Compressor is installed, its oil m ust first be drained and m easured to leave only th at like am ount drained and m easured in the oil compressor. 3. O N A N R -4 C O M P R E S S O R S Y S T E M W IT H S IG N S O F A B U N D A N T O IL LEA K A G E: •? O N L Y T H E A C C U M U L A T O R S H O U L D BE R E M O V E D from the system, oil drained and then m easured to determ ine correct quantity of oil replace­ ment. If the am ount drained is 60 ml (2 oz.) or more, replace with like am ount. If less than 60 ml (2 oz.), replace with 60 ml (2 oz.) of new oil. • ? I N A D D IT IO N to this am ount, add 30 ml (1 oz.) to replace the am ount captured in the old desiccant of the replaced accu m u lato r assem bly. Because the R-4 Compressor has no oil sump, it is not necessary to remove this compressor to m easure oil. R-4 Compressor Systems Remove only the accum ulator. D rain, m easure and record q u antity of oil in accum ulator. (It is not necessary to remove and drain the R -4 Com pressor because the R-4 C om pressor only retain s a m inim um q u a n tity of oil-it doesn’t have an oil sum p area.) If less than 90 ml (3 oz.), add 90 ml (3 oz.) of new oil to system. If more th an 90 ml (3 oz.), add same am ount of new oil as drained. If a new A ccum ulator m ust be added to R-4 system, add 30 ml (1 oz.) of oil to com pensate for th a t held/absorbed by the original A ccum ulator dessicant. 1. If there are no signs of excessive oil leakage, add the follow ing am o u n t o f oil depending on com ponent replaced: For A-6 & R-4 Com pressor System s - Evaporator - 90 ml (3 oz.). LIG H T T R U C K SE RV IC E M A N U A L DISCHARGING EVACUATING ADDING OIL AND CHARGING PROCEDURES FOR CCOT A /C SYSTEMS The refrigerant system m ay be Discharged, Evacuated and C harged using J-23500-01 air conditioning service Refrigerant Charge Overhead System C-K Models G Models C60 System 5 lb».-4 oz. 3 Lbs. -1 2 ox. 5 lbs. 3 lbs. AIR CONDITIONING C harging Station or the J-5725-04 M anifold and Gage Set and 420 ml (14 oz.) disposable cans of R - 12. C harging lines from the C harging Station or M anifold and G age Set require the use of gage adapters to connect to system service fittings. A straight gage A dapter J-5420 and a 90° angle gage A dapter J-9459 are available. CAUTION:Always wear goggles and wrap a clean cloth around fittings and connections when doing work that involves opening the refrigerant sys­ tem. If liquid refrigerant comes into contact with the skin of eyes injury can result. DISCHARGING THE CCOT A /C SYSTEM In replacing any of the air conditioning refrigeration components the system m ust be completely discharged of R-12. IB-31 A L W A Y S D IS C H A R G E SY ST E M AT LO W SID E S E R V IC E F IT T IN G . 1. With ignition tu rn ed OFF, rem ove p ro tec tiv e cap from low -side service hose fitting and connect Charg­ ing S tation J-23500-01 G age Set as show n in Fig. IB-22. O r w ith ignition turned O F F and protective cap re­ m oved from LO W -SID E service fitting, discharge sy stem by SLO W LY c o n n ec tin g a gage h o se to LO W -SID E service fitting on A ccum ulator and dis­ charging into oil bottle (Fig. IB-23). As hose is slowly tightened dow n into schrader valve, R-12 will be in to discharge from the system into the container. If no discharge o c cu rs, check fo r m issing or defective schrader d ep ressor in LIG H T T R U C K SERVICE M A N U A L IB-32 AIR CONDITIONING 1 CLOSE A L L CO NTRO LS J 23500-01 SE R V IC E C H A R G IN G S T A T IO N 3 F U L L Y OPEN GAUGE SET V A C U U M V A L V E 4 CONNECT LOW-SIDE GAUGE HOSE TO LOW-SIDE PRESSURE SERVICE F IT T IN G ON V E H IC L E 'S AC C U M U LA TO R ASM. USING J 5420 ADAPTER 5 "S L O W L Y " OPEN LOW-SIDE V A L V E ON GAUGE SET TO DISCHARGE 6 RE-CONNECT V A C U U M HOSE TO PUMP A F T E R DISCHARGE DO NO T CONNECT HIG H-SIDE HOSE TO A /C SYSTEM 2 DISCO NNECT V A C U U M HOSE A T V A C U U M PUMP & PLACE IN T O CAN (SEE “ N O T E " BELOW) V A C U U M PUMP NOTE: AN EMPTY 3 LB. COFFEE CAN W ITH A PLASTIC L ID CROSS-SLIT (X'ed) TO ALLO W HOSE E N T R Y IS R ECOM M ENDED. 4342 Fig. 1B-22--Discharging The CCOT System With J-23500-01 Charging Station L IG H T T R U C K SE R V IC E M A N U A L AIR CONDITIONING IB-33 Prior to Evacuation, check the low pressure gage for proper calibration. W ith the gage disconnected from the refrigeration system, be sure th at the pointer indicates to the center of " O " . Lightly tap gage a few tim es to be sure pointer is not sticking. If necessary, calibrate as follows: a. Remove cover from gage. b. Holding gage pointer adjusting screw firmly with one hand, carefully force pointer in the proper direction in proper am ount to position pointer through the center of " O " position. T ap gage a few times to be sure pointer is not sticking. Replace gage cover. J-23500-01 CHARGING STATION METHOD Fig. 1 B-23--Discharging and Collecting Oil From System Without Charging Station J-23500-01 2. W hen the system is com pletely discharged (no vapor escaping with hose fully-tightened down), m easure, record and discard any of the collected refrigerant oil. If this q u antity is 15 ml (1 /2 oz.) O R M O R E , it must be added to system, plus any trapped in removed parts before Evacuation and C harging with R-12 (R efer to C C O T R efrigerant Oil D istribution for specific quan­ tity instructions on oil found in removed parts). 3. W ith the low-side of system fully discharged, check high-side system fitting (on muffler) for rem aining pressure by connecting a downward directed 36 in. section J-5418-36B ch arg in g line w ith atta ch ed J-25498 straight or J-25499 90° angle fitting adapter S L O W L Y tightened down to depress the fitting valve. 4. If pressure is found on the high-side of the system, attem pt to discharge high-side using sam e procedure as used for low-side. (This condition indicates a restriction and high-side com ponents should be removed an d/or diagnosed to d eterm ine the area restricted.) Evacuating CCOT A /C SYSTEM If the system has been opened for any repair, or the R-12 charge lost, the system m ust be evacuated prior to Charging to remove any trace of air or m oisture th a t may have entered. Evacuation and C harging is a combined procedure, with all lines and gauges, as well as the system, to be purged with R - 12 and Evacuated ju st prior to Charging. There are three standard R-12 Evacuate and C harge procedures which include Oil Addition: • J-23500-01 C harging Station M ethod • Disposable C an M ethod • D rum M ethod U nder no circum stances should alcohol be used in the system in an attem p t to remove m oisture, regardless of the successful use of alcohol in other refrigerant systems. Follow C h arg in g instructions provided w ith the J-23500-01 C h arg in g S tatio n in use w ith the following exceptions: 1. DO N O T C O N N E C T T H E H IG H P R E S S U R E L IN E TO T H E A IR C O N D IT IO N G SY ST E M . 2. K EEP T H E H IG H P R E S S U R E V ALVE O N T H E C H A R G IN G S T A T IO N C L O SED A T A LL T IM E S . 3. P E R F O R M T H E E N T IR E E V A C U A T E A N D CHARGE PROCEDURE THROUGH THE A CCU­ M U L A T O R L O W -S ID E P R E S S U R E S E R V IC E F IT T IN G . 4. A D D IN G O IL T O T H E C C O T A /C S Y S T E M should take place A F T E R Discharge A N D B EFO R E Evacuation procedures by removing the refrigeration suction hose at the A ccum ulator outlet pipe connection, pouring the correct quantity of refrigerant oil into the hose or pipe and then properly reconnecting hose to pipe (R efer to Discharging Step No. 2 and C C O T R efrig eratio n Oil D istribution for specific q u a n tity instructions). 5. Following these procedures will prevent accidental high-side vehicles system pressure being subjected to the C harging Station in the event an error is m ade in valve sequence during compressor operation to pull in the R-12 charge. DISPOSABLE CAN OR REFRIGERANT DRUM METHOD A D D IN G O IL T O T H E C C O T A /C S Y S T E M should take place after discharge and before evacuation procedure by removing the refrigeration suction hose at the A ccum ulator outlet pipe connection, pouring the correct quantity of refrigerant oil into the hose or pipe and then properly reconnecting hose to pipe (Refer to Discharging Step No. 2 and C C O T Refrigeration Oil D istribution for specific quantity instructions). • If the R -12 drum is used, place it on a scale and note the total weight before Charging. W atch the scale during C harging to determ ine the am ount of R -12 used. • If disposable 420 ml (14 oz.) R-12 cans are used, close the tapping valve and then attach can(s) following instructions included with the tapping valve or tapping manifold adapter. 1. Connect M anifold G age Set J-5725-04 as shown in Fig. IB-24. • LOW pressure gage set valve to A ccum ulator fitting • Gage set center hose to R - 12 source • High pressure gage set valve to vacuum pump LIG H T T R U C K SERVICE M A N U A L IB-34 AIR CONDITIONING J5725-04 MANIFOLD USING J-5420 ADAPTER GAUGE SET TH,S HIGH PRESSURE VALVE IS / OPEN AND VACUUM PUMP LINE / DISCONNECTED ONLY DURING / EVACUATION OPEN DURING EVACUATION AND CHARGING THIS HIGH PRESSURE VALVE IS CLOSED AND LINE DISCONNECTED DURING DISCHARGING AND CHARGING HIGH SIDE VALVE VALVE VACUUM PUMP ACCUMULATOR CAUTJON: Make sure outlet valve on opener is closed (clockwise) before installing opener to R-12 container. 14 OZ. CANS MULTI-CAN DISPENSING UNIT USING J6271-01 SINGLE CAN OR 30 LB. DRUM HAS OWN OPENER-VALVE DECREASE OF WEIGHT ON SCALE INDICATES CHARGE ADDED CLOSED D U R IN G / EVACUATION X OPEN AND INVERTED DURING CHARGING USING J23390 OPENER-VALVE FOR 12 LB. CAN J6272-02 MULTI CAN OPENER-VALVE Fig. 1 B-24--Charging the CCOT A /C System with Disposable Can or Refrigerant Drum. 2. To begin evacuation, w ith M anifold G age Set and V acuum Pum p as shown in Fig. 1B-24 slowly open high and low-side gage valves and begin vacuum pum p operation. Pum p the system until low-side gage reaches 95-98 kPa (28 to 29 in.) vacuum or more. In all Evacuation procedures, the specification of 95-98 kPa (28 to 29 in.) of m ercury vacuum is used. This specification can only be reached a t or near sea level. For each 304.8 m (1,000 ft) above sea level, specifica­ tion should be lowered by one inch of m ercury vacuum. A t 1524 m (5,000 feet) elevation only 78-81 kPa (23 to 24 in.) of vacuum is required. If prescribed vacuum cannot be reached, close vacuum control valve, shut off pum p and look for a leak at connections or pump. LIG H T T R U C K SE RV IC E M A N U A L 3. W hen the system is fully Evacuated, close the high-side gage set valve and turn O F F the vacuum pump. 4. W atch low-side gage to be sure vacuum holds for five(5) m inutes at gage set and then proceed to Charging. 5. If Vacuum Does N ot Hold For five(5) M inutes, charge system with 240 ml (1 /2 lb) R-12 and leak check. Discharge system again then repair leak as necessary. Repeat Evacuation procedure. TO BEGIN CHARGING OF THE CCOT A /C SYSTEM 1. S tart engine, run with choke open and fast idle speed reduced to normal idle, set A /C control lever on O FF. AIR CONDITIONING 2. W ith the R efrig eran t-12 drum or 420 ml (14 oz.) can(s) inverted, open R-12 source valve(s) and allow 480 ml (1 lb.) or 1 to 2, 420 ml (14 oz.) can(s) of liquid R - 12 to flow into system through low-side service fitting on accum ulator (R efer to Fig. 1B -31). 3. As soon as 480 ml (1 lb.) or 1 to 2, 420 ml (14 oz.) can (s) of liquid R -12 has been added to system , im m ediately engage the com pressor, by setting the A /C control lever to N O R M and blower speed on H I, to draw in the rem ainder of the R - 12 charge. The C harging operation can also be speeded up by using a large volume fan to pass air over the condenser. If condenser tem perature is m aintained below charging cylinder tem perature, R efrig eran t-12 will enter system more rapidly. 4. Shut off R-12 source valve and run engine for 30 seconds to clear lines and gages. 5. W ith the engine running, remove the charging low-side hose adap ter from the A ccum ulator Service fitting. Unscrew rapidly to avoid excess R-12 escape from system. CAUTION:Never remove a gage line from its adapter when line is connected to A /C system. Always remove the line adapter from the service fitting to disconnect a line. Do not remove charg­ ing hose at set while attached to accumulator. This will result in complete discharge of system due to the depressed schrader valve in service low-side fitting, and may cause personal injury due to escaping R-12. 6. R eplace protective cap on accum ulator fitting. 7. Leak check system with J-6084 leak detector. 8. W ith system fully C harged and leak-checked, continue to operate system and test for proper system pressures as outlin ed under P E R F O R M A N C E P R E S S U R E T E M P E R A T U R E D A T A C C O T A /C S Y S T E M D IA G N O S T IC P R O C E D U R E . IB-35 2. The expansion tube (orifice) screen is plugged. 3. The compressor inlet screen is plugged. 4. An evaporator fails because of inside-out (internal) corrosion. DO N O T R E P L A C E the accum ulator assembly when: 1. If a sm all dent is found in the outer shell of the accum ulator. 2. W hen a vehicle is involved in a collision and no physical perforation to the accu m u lato r is found. An open refrigerant line should be capped or have a plastic bag tightly taped around it. COMPRESSOR C-K SERIES Removal (Fig. IB-33) 1. Discharge the system. 2. Remove connector attaching bolt and connector. Cap or plug open connections at once. 3. Disconnect electrical lead to clutch actuating coil. 4. Loosen brace and pivot bolts and detach belt. 5. Remove the nuts and bolts attaching the compressor brackets to the m ounting brack et. Rem ove the compressor. 6. Before beginning any compressor disassembly, drain and m easure oil in the compressor. Check for evidence of contam ination to determ ine if rem ainder of system requires servicing. Com pressor servicing inform ation is located in the U nit R epair M anual. ACCUMULATOR ASSEMBLY T he accum ulator assembly for the C C O T system has a service replacem ent which includes two " O " rings (for the inlet and outlet connections). The dessicant within the shell is N O T serviced sep arately - it is p a rt of the sealed accum ulator assembly. R efer C C O T R efrigerant oil distribution for presence of refrigerant oil and service conditions when the accum ula­ tor m ust be rem oved from the vehicle to m easure the am ount of oil present inside the accum ulator. T he accum ulator assembly should be replaced only when: 1. A physical perforation to the accum ulator is found resulting in a leak. Fig. 1B-25--Checking Evaporator Inlet and Acuumulator Outlet Temperatures LIG H T T R U C K SE RV IC E M AN U AL IB-36 AIR CONDITIONING 3 0 5 - 3 5 0 V -8 C-K M O D E L S ^ T 3 0 5 - 3 5 0 V -8 4 5 4 V -8 C- G l t r ^ M O D E LS A N D M O T O R H O M E C H A SS IS M O DELS 4 5 4 V -8 Fig. 1B-26--Compressor Mounting L IG H T T R U C K SERVICE M A N U A L M O T O R H O M E C H A SS IS AIR CONDITIONING Installation 1. If oil previously drained from the compressor upon removal shows no evidence of contam ination, replace a like am ount of fresh refrigeration oil into the com pres­ sor before reinstallation. If it was necessary to service the entire system because of excessive contam ination in the oil removed, install a full charge of fresh refrigera­ tion oil into the compressor. 2. Position com pressor on th e m ounting b rack et and install all nuts, bolts and lock washers. 3. Install the connector assem bly to the compressor rear head, using new "O " rings coated with clean refrigera­ tion oil. 4. Connect the electrical lead to the coil and install and adjust compressor belt. 5. Evacuate, charge and check the system. 2. 3. 4. 5. 6. 7. IB-37 reinstallation. If it is necessary to service the entire system because of excessive contam ination in the oil removed, install a full charge of fresh refrigeration oil in the compressor. (R efer to Checking Compressor Oil C harge in the diagnosis section of this service m anual.) Position com pressor on th e m ounting brack et and install the nuts, bolts, lock washers, and ground wire. Install the connector assembly to the com pressor rear head, using new " O " ring coated with clean refrigera­ tion oil. Connect the electrical lead to the coil and install and adjust compressor belt, using idler pulley. Refer to "C om pressor Belt Tension A d justm ent." Evacuate, charge and check the system. Replace air cleaner. On G series, replace the engine cover. Connect the battery ground cable. Compressor Belt Tension Adjustment G and Motor Home Chassis Models Removal (Fig. IB-26) 1. D isconnect b attery ground cable. 2. Disconnect compressor clutch connector. 3. Purge the system of refrigerant. 4. Release the belt tension at th e idler pulley and remove the bit from the com pressor pulley. On some vehicles it m ay be necessary to remove the crankshaft pulley in order to remove the belt. 5. G S eries-R em ove the two bolts and two clamps th at hold the engine cover and remove the cover. 6. Remove the air cleaner to aid access to the compressor. 7. Remove fitting and muffler assem bly and cap or plug all open connections. 8. Remove the nuts and bolts attaching the compressor to the bracket. 9. Remove the engine oil tube support bracket bolt and nut from the compressor, and the compressor clutch ground lead. A djust the compressor belt to the specifications shown in the Engine section of the Service M anual. On some G and M otor Home Chassis units it m ay be necessary to increase idler pulley slack adjustm ent. This may be accomplished by (1) Remove and discard the idler adjustm ent bolt. (2) Remove the idler backing plate and elongate all 3 adjusting slots 1/2 in. inboard or outboard as required. (3) Reinstall the idler assembly and adjust belt tension using a lever (screwdriver, etc.) to move the pulley outboard until proper belt tension is reached. If the belt is being replaced it m ay be necessary to remove and replace the throttle cable during the belt replacem ent. If so check throttle cable adjustm ent upon completion. It may also be necessary to remove the crankshaft pulley to install a new compressor belt. Before beginning any com pressor disassembly, drain and m easure oil in the compressor. C heck for evidence of contam ination to determ ine if rem ainder of system requires servicing. Com pressor Servicing inform ation is located in the U nit R epair M anual. Installation 1. If th e oil d rain ed from th e com pressor showed no evidence of contam ination replace the sam e am ount of fresh refrig eratio n oil into th e com pressor before Fig. 1 B-27--Condenser Installation (C-K Series) LIG H T T R U C K SERVICE M A N U A L IB -38 AIR CONDITIONING C60 SYSTEM--C-K SERIES CONDENSER - C-K SERIES (FIG. IB-27) Replacement (Fig. IB-27) 1. Disconnect battery ground cable. 2. D ischarge system. 3. Remove the grille assembly. 4. Remove the rad iato r grille center support. 5. Remove the left grille support to upper fender support (2) screws. 6. Disconnect the condenser inlet and outlet lines and the outlet tube line a t the right end of the condenser. C ap or plug all open connections at once. 7. Remove the condenser to rad iato r support screws. 8. Bend the left grille support outboard to gain clearance for condenser removal. 9. Remove the condenser assem bly by pulling it forward and then lowering it from the vehicle. 10. To install a new condenser, reverse Steps 1 thru 9 above. A dd one fluid ounce of clean refrigeration oil to a new condenser. Use new " O " rings, coated with clean refrigeration oil, when connecting all refrig eran t lines. 11. Evacuate, charge and check the system. ACCUMULATOR - ALL Replacement 1. Disconnect the battery ground cable and the com pres­ sor clutch connector. 2. Discharge system. 3. Disconnect the accum ulator inlet and outlet lines and cap or plug the open connections at once. 4. Remove the accum ulator bracket screws and remove the accum ulator from the vehicle. 5. D rain any excess refrigerant oil from the accum ulator into a clean container. M easure and discard the oil. 6. If a new accum ulator is being installed, add one ounce of clean refrigeration oil to the new accum ulator PL U S an am ount equal to th a t drained in Step 5 above. 7. To install the new accum ulator, reverse Steps 1 thru 4 above. Connect all lines using new " O " rings, coated with clean refrigeration oil. Do not uncap the new unit until ready to fasten the inlet and outlet line to the unit. 8. Evacuate charge and check the system. BLOWER ASSEMBLY - C-K SERIES Replacement 1. 2. 3. 4. D isconnect the b attery ground cable. Disconnect the blower m otor lead and ground wires. Disconnect the blower m otor cooling tube. Rem ove th e blow er to case a tta c h in g screw s and remove the blower assem bly. Pry the blower flange aw ay from the case carefully if the sealer acts as an adhesive. 5. Remove the nut attach in g the blower wheel to the m otor shaft and separate the assemblies. 6. To install, reverse Steps 1 th ru 5 above; replace sealer as necessary. L IG H T T R U C K SE RV IC E M A N U A L EVAPORATOR CORE Replacement (Fig. IB-28) 1. Disconnect the battery ground cable. 2. Discharge system. 3. Remove the nuts from the selector duct studs project­ ing through the dash panel. 4. Remove the cover to dash and cover to case screws and remove the evaporator case cover. 5. Disconnect the evaporator core inlet and outlet lines and cap or plug all open connectins at once. 6. Remove the expansion tube as outlined under expan­ sion tube replacem ent. 7. Remove the evaporator core assembly. 8. To install, reverse Steps 1 thru 7 above. Add 90 ml (3 oz.) of clean refrigeration oil to a new evaporator core. U se new “ O ” rings, coated w ith clean refrigeration oil, w hen connecting refrigerant lines. Be sure cover to case and dash panel sealer is in tact before reinstal­ ling cover. 9. Evacuate, charge and check the system. EXPANSION TUBE-C-K,& G The expansion tube is located in the evaporator core inlet line. Replacement 1. Discharge system. 2. Disconnect the condenser to evaporator line at the evaporator inlet. C ap the open line at once. 3. Using needle-nose pliers, remove the expansion tube from the evaporator core inlet line. 4. Remove the expansion tube " O " ring from the core inlet line. 5. To install, reverse Steps 1 thru 4 above. Install the expansion tube using a new " O " ring coated w ith clean reg rig eratio n oil, by inserting the sh o rt screen end of the tube into the evaporator inlet line. 6. Evacuate, charge and check the system. AIR CONDITIONING IB-39 LIG H T T R U C K SERVICE M A N U A L IB-40 AIR CONDITIONING UPPER CENTER DISTRIBUTOR DUCT RIGHT HAND OUTLETS LEFT DISTRIBUTOR DUCT AND FOOT COOLER LOWER CENTER DISTRIBUTOR DUCT Fig. lB-30--Air Selector and Ducts (C-K Series) SELECTOR DUCT AND HEATER CORE ASSEMBLYC-K Replacement (Fig. IB-30) 1. Disconnect the b attery ground cable. 2. D rain the radiator and remove the heater hoses from the core tubes. Plug the core tubes to prevent coolant spillage during removal. 3. Remove the glove box and door as an assembly. 4. Remove the center duct to selector duct and instrum ent panel screws and remove the center lower and center upper ducts. 5. D isconnect the bowden cable at the tem perature door. 6. Rem ove the nuts from th e three selector duct studs projecting through the dash panel. 7. Remove the selector duct to dash panel screw (inside vehicle). 8. Pull the selector duct assembly rearw ard until the core tubes clear the dash panel. Lower the selector assembly far enough to gain access to all vacuum and electrical harnesses. 9. D isconnect th e vacuum and e lectrical harness and L IG H T T R U C K SE RV IC E M A N U A L remove the selector duct assembly. 10. Remove the core m ounting strap screws and remove the core. 11. To install, reverse Steps 1 thru 10 above. 12. Refill coolant system and connect the battery ground strap. Check tem perature door cable adjustm ent. KICK PAD VALVE - C-K SERIES Replacement (Fig. IB-31) 1. 2. 3. 4. Disconnect the vacuum hose a t the actuator. Unhook the valve return spring at the actuator end. Remove the actuator bracket m ounting screws. Remove the cam to actuator arm screw and separate the actuator and bracket from the cam. 5. Remove the actuator to bracket nuts and separate the actuator and bracket. 6. To install reverse Steps 1 thru 5 above. PLENUM VALVE - C-K SERIES Replacement (Fig. IB-31) 1. Raise the hood. 2. Remove the cowl plastic grille. 3. Remove the three cowl to valve assembly screws and remove the valve assembly from the vehicle. 4. Remove the actuator arm pushnut. AIR CONDITIONING IB-41 4. Remove the control to instrum ent panel screws and lower the control far enough to gain access to the control assembly. Be careful not to kink the bowden cable. 5. Disconnect the bowden cable, vacuum harness and electrical harness at the control. 6. Remove the control. 7. If a new unit is being installed, transfer the m aster blower switches to the new control. 8. To reinstall, reverse Steps 1 th ru 6 above. C heck control operation. TEMPERATURE DOOR CABLE ADJUSTMENT - C-K MODELS 1. Remove glove box and door assembly. 2. Loosen the cable attaching screw at the selector duct assembly. 3. M ake sure the cable is installed in the bracket on the selector duct assembly. 4. Place tem perature lever in full CO LD position and hold while tightening cable attaching screw. MASTER SWITCH AND/OR BLOWER SWITCH C-K SERIES The m aster switch is located on rear of the control assembly. Fig. 1B-31--Air Inlet Valves (C-K Models) 5. Remove the actuator to valve nuts and separate the valve and actuator. 6. To install, reverse Steps 1 th ru 5 above. CONTROL ASSEMBLY - C-K SERIES Removal (Fig. IB-32) Replacement 1. Disconnect the battery ground cable. 2. Remove the instrum ent panel bezel. 3. Remove the control to instrum ent panel screws and allow control to rest on top of the radio. 4. Remove the switch to control screws, disconnect the electrical harness (and vacuum harness on m aster switch) at the switch and remove the switch assembly. 5. To install a new switch, reverse Steps 1 thru 4 above. 1. Disconnect the b attery ground cable. 2. Remove the radio as outlined in Section 8 of this m anual. 3. Remove the instrum ent panel bezel. VACUUM TANK The vacuum tank is m ounted to the engine side of the dash panel above the blower assembly (Fig. IB-33). LIG H T T R U C K SERVICE M A N U A L IB-42 AIR CONDITIONING GR A Y-TO PLENUM VALVE V A C U U M TANK ORANGE CAM LEVER CABLE RECIRC. AIR DEFROSTER BLUE V IE W HEATER ASSEMBLY C O N TR O L A CTUA TO R N O COLOR STRIPE ACTUA TO R V IE W V IE W Fig. 1B-34--Vacuum Line Routing - C-K Models Replacement 1. Disconnect the vacuum lines at the tank. 2. Remove the tan k to dash panel screws and remove the tank. 3. To install, reverse Steps 1 and 2 above. FUSE A 25 am p fuse, located in the junction block protects the entire air conditioning system except for the blower circuit, the fuse for the blower circuit is located in the electrical wiring between the junction block and the blower relay. BLOWER MOTOR RESISTOR The blower m otor resistor is located in the blower side of the blow er-evaporator case (Fig. IB-35). Replacement OVERHEAD SYSTEM--C-K MODELS 2. Rem ove th e resistor to case a tta c h in g screw s and remove the resistor. The O verhead System is used in conjunction with the C60 System. Since replacem ent of C60 System components has been covered previously, only those components peculiar to the O verhead System will be covered in this section. 3. P lace th e new resistor in position and install the attaching screws. REAR DUCT 1. Disconnect the wiring harness at the resistor. 4. C onnect the resistor wiring harness. BLOWER MOTOR RELAY - ALL The blower m otor relay is located on the blower side of the blow er-evaporator case (Fig. 35). This duct covers the blower-evaporator assembly, at the rear of the vehicle, and incorporates four adjustable air outlets (Fig. IB-36). Replacement Replacement 1. Disconnect th e wiring harness at the relay. 2. Remove the relay to case attach in g screws and remove the relay. 1. Disconnect the battery ground cable. 2. Disconnect the drain tube from the rear duct. 3. Remove the screws securing the duct to the roof panel and rear header brackets. 3. Place the new relay in position and drive the m ounting screws. 4. Remove the duct. 4. Connect the relay w iring harness. 5. To install, reverse Steps 1 thru 4 above. L IG H T T R U C K SE RV IC E M A N U A L AIR CONDITIONING IB-43 A /C HARNESS ASM PRESSURE C Y C L IN G SWITCH BLOW ER RESISTOR BLOW ER R ELAY ACC UM ULATO R BLOW ER ASM G R O U N D E V A P O R A TO R BLOW ER ASM V IE W A Fig. 1B-35--Engine Compartment W iring Harness (C-K Models) BLOWER MOTOR ASSEMBLY Removal (Fig. IB-38) 1. Disconnect the battery ground cable. 2. Remove the rear duct as outlined previously. 3. Disconnect the blower motor ground strap. 4. Disconnect the blower motor lead wire. 5. Remove the lower to upper blower-evaporator case screws and lower the lower case and motor assembly. NOTICE: Before removing the case screws, support the lower case to prevent dam age to the case or motor assemblies. 6. Rem ove the m otor retaining stra p and rem ove the motor and wheels. Remove the wheels from the motor shaft. Fig. lB-36--Rear Duct C-K & G Overhead System BLOWER MOTOR RESISTOR The blower m otor resistor is located on the cover side of the C60 System blow er-evaporator as shown in Fig. 1B-37. Replacement 1. Disconnect b attery ground cable. 2. Disconnect the electrical harness at the resistor. 3. Remove the resistor attaching screws and remove the resistor. 4. To install a new resistor, reverse Steps 1 thru 3 above. Installation 1. Place the blower wheels onto the m otor shaft making sure the wheel tension springs are installed on hub of wheels. Be sure th at the blower wheels are installed as shown in Fig. IB-39. 2. Install the blower motor retaining strap and foam. 3. Place the blower m otor and wheel assembly into the lower case. Align the blower wheels so th at they do not contact the case. 4. Place the lower case and blower motor assembly in position in the vehicle and install the lower to upper case screws. L IG H T T R U C K SERVIC E M AN U AL IB-44 AIR CONDITIONING Fig. 1B-37--Overhead System Front W iring (C-K Models) Fig. 1 B-38--Blower-Evaporator (C-K Overhead System) NOTICE: R o tate the blower wheels to m ake sure th at they do not rub on the case. 5. Install the center ground wire and connect the blower lead wire. 6. Install the rear duct assem bly as described previously. 7. Connect th e b attery ground cable. EXPANSION VALVE This sytem incorporates an expansion valve which does not utilize and external equalizer line (Fig. IB-40). Fig. 1B-39--Blower M otor (C-K Overhead System) Removal 1. Disconnect b attery ground cable. 2. Purge the system of refrigerant. 3. Remove the rear duct as outlined previously. 4. Disconnect the blower motor lead and ground wires. 5. Remove the lower to upper blower-evaporator case screws and lower the lower case and motor assembly. NOTICE: Before removing the case screws, support the lower case and motor assemblies to prevent dam age to the case or motor assemblies. 6- Rem ove the expansion valve sensing bulb clamps. LIG H T T R U C K SE RV IC E M A N U A L AIR CONDITIONING 7. Disconnect the valve inlet and outlet lines and remove the expansion valve assembly. C ap or plug the open connections a t once. 1. Remove caps or plugs from system connections and install the new valve assembly using new " O " rings coated with clean refrigeration oil. 2. Install the sensing bulb, m aking sure th at the bulb m akes good contact with the core outlet line. 3. Install the lower case and blower motor assemblies. Connect the blower motor lead and ground wires. 4. Install the rear duct as outlined previously. 5. Connect the battery ground cable. 6. Evacuate, charge and check the system. EVAPORATOR CORE (Fig. IB-40) 6. 7. 8. 9. 3. Install the upper case and supports to the core. 4. Install the lower core case and blower assembly. 5. Install the blower-evaporator assembly to the roof and install the support to roof rail screws. 6. Connect the refrigerant lines to the blower-evaporator unit using new " O " rings coated with clean refrigera­ tion oil. 7. Connect the blower lead and ground wires. 8. Install the rear duct as outlined previously. 9. Connect the battery ground cable. 10. Evacuate, charge and check the system. Removal 5. Install the sensing bulb to the evaporator outlet line as shown in Fig. IB-44; make sure the bulb has good contact with the line. Add 3 oz. clean refrigeration oil when installing a new core. Installation 1. 2. 3. 4. IB-45 Disconnect the b attery ground cable. Purge the system or refrigerant. Remove the rear duct as outlined previously. Disconnect the blower m otor lead and ground wire connections. D isconnect the re frig e ra n t lines a t the re a r of the b low er-evaporator assem bly. C ap or plug the open connections at once. Rem ove th e blow er-evaporator support to roof rail screw s, lower th e blow er-evaporator assem bly and place it on a work bench upside down. Remove the lower to upper case screws and remove the lower case assembly. Remove the support to upper case screws and remove the upper case from the evaporator core. Remove the expansion valve inlet and outlet lines and cap or plug the open connections at once. Remove the expansion valve capillary bulb from the evaporator outlet line and remove the valve. Remove the plastic pins holding the screen to the core and remove the screen. Installation BLOWER MOTOR SWITCH The three-speed (L O -M E D -H I) blower motor switch is located in the instrum ent panel, just to the left of the ash tray (Fig. IB-41). Replacement 1. Disconnect the battery ground cable. 2. Remove the switch retaining screws. 3. Disconnect the wiring harness at the switch and remove the switch. 4. To install, reverse Steps 1 thru 3 above. FUSE The Four Season portion of this system is protected by a 25 am p fuse in the junction block. The rear blower high speed circuit is protected by a 20 am p in-line fuse, located between the junction block and the rear blower motor switch. 1. Install the wire screen to the front of the core and insert the plastic pins. 2. Install the expansion valve inlet and outlet lines using new " O " rings coated with clean refrigeration oil. E VA PO R A TO R SCREEN B LO W E R -E V A P O R A TO R UPPER CASE Fig. 1 B-40--Expansion Valve C69 System Fig. 1B-41--Blower Switch (C-K Overhead System) LIG H T TR U C K SERVICE M A N U A L IB-46 AIR CONDITIONING C60 SYSTEM-G SERIES CONDENSER - G Series Replacement (Fig. IB-42) 1. Disconnect battery ground cable. 2. Purge the system of refrigerant. 3. Remove grille, hood lock, and center hood lock support as an assembly. 4. D isconnect condenser inlet and o u tlet lines at condenser. 5. Remove screws attaching left side condenser bracket to radiator. 6. Remove screws attaching right side condenser bracket to condenser. 7. Remove condenser from vehicle. 8. Remove left hand bracket from condenser. 9. To install new condenser, reverse steps 3 th ru 8 above. Add 30 ml (1 oz.) of clean refrigeration oil to a new condenser. 10. Evacuate charge and test the system. Refer to Fig. IB-61 th ru IB-66 for condenser inlet and outlet connections, com pressor refrigerant line connections, and general regrigerant line routing and connections. HEATER AIR DISTRIBUTOR AND EXTENSION DUCT - G SERIES Replacement (Fig. IB-43) 1. 2. 3. 4. Disconnect battery ground cable. Remove engine cover. Remove evaporator-blow er shield. Remove shield bracket. 5. Remove left floor outlet deflector and bracket. 6. Loosen steering column to instrum ent panel reinforce­ m ent screws. Remove one screw. Torque both screws on installation. 7. Disconnect speedometer cable a t m eter. HEATER CORE - G SERIES Replacement 1. Disconnect battery ground cable. 2. Remove engine cover as outlined in Section 6A of this manual. 3. Remove steering column to insrum ent panel attaching bolts and lower column. 4. Remove upper and lower instrum ent panel attaching screws and radio support bracket attaching screw. 5. Raise and support right side of instrum ent panel. 6. Remove right lower instrum ent panel support bracket. 7. Remove recirculating air door vacuum actuator. Refer to Fig. IB-44. 8. Disconnect tem perature cable and vacuum hoses at distributor case. 9. Remove heater distributor duct, refer to Fig. 1B-45. 10. Remove 2 defroster duct to dash panel attaching screws (below windshield). 11. W orking from the engine com p artm en t, disconnect heater hoses and plug to prevent w ater spillage. 12. Remove three (3) nuts from bolts attaching heater core case to dash panel and one (1) screw at lower right corner (inside). 13. Remove distributor assembly from vehicle. 14. Remove gasket to expose screws attaching case sections together as shown in Fig. 1B-46. 15. Remove tem perature cable support bracket. 16. Remove case attaching screws and separate case. 17. Remove heater core. 18. To install new heater core, reverse Steps 2 thru 17 above. BLOWER MOTOR - G SERIES Replacement 1. Disconnect battery ground cable. G Series - Remove the coolant recovery tank, and power antenna as outlined in Sections 6 and 9. 2. Disconnect the blower m otor lead wire. 3. Remove the five blower motor m ounting screws and remove the motor and wheel assembly. Pry gently on the blower flange if the sealer acts as an adhesive. 4. Rem ove the blower wheel to m otor shaft n u t and separate the wheel and motor assemblies. 5. To install a new motor, reverse Steps 1 thru 4 above. The following steps should be taken to assure proper installation: a. Assemble the blower wheel to the motor with the open end of the wheel away from the blower motor. b. If the motor mounting flange sealer has hardened, or is not intact, remove the old sealer and apply a new L IG H T T R U C K S E R V IC E M A N U A L AIR CONDITIONING IB-47 Fig. 1B-43--Heater Distributor Duct-G Series Fig. 1B-44--Recirculating Air Door Vacuum Actuator bead of sealer to the entire circum ference of the m ounting flange, c. C heck blower operations: blower wheel should rotate freely with no interference. Fig. 1B-45--Heater Distributor Duct EVAPORATOR CORE Replacement (Fig. IB-54) 1. Disconnect battery ground cable. 2. Purge system of refrigerant. LIG H T T R U C K SERVICE M A N U A L IB-48 AIR CONDITIONING 2. Remove the headlam p switch control knob. 3. Remove the instrum ent panel bezel. 4. Remove the control to in stru m en t panel attach in g screws. 5. Remove the tem perature cable eyelet clip and m ount­ ing tab screw. 6. Pull the control through the instrum ent panel opening as follows: First pull the lower right m ounting tab through the opening, then the upper tab and finally the lower right tab. 7. D isconnect electrical and vacuum connections and remove the control assembly. 8. To install, reverse Steps 1 thru 7 above. Check tem per­ ature door operation; adjust if necessary. BLOWER SWITCH Replacement (Fig. IB-48) 3. Remove coolant recovery tank and bracket as outlined earlier. 4. D isconnect all e lectrical connectors from core case assembly. 5. Remove bracket at evaporator case. 6. Remove right hand m arker lam p for access. 7. Disconnect accum ulator inlet and outlet lines and 2 brackets attaching accum ulator to case. 8. Disconnect evaporator inlet line. 9. Remove three (3) nuts and one (1) screw attaching module to dash panel. 10. Remove core case assem bly from vehicle. 11. Remove screws and separate case sections. 12. Remove evaporator core. 13. To install new core, reverse Steps 3 thru 14 above. 14. Add 90 ml (3 oz.) 525 viscosity refrigeration oil to a new condenser. 15. Evacuate charge and check the system. 1. Disconnect the battery ground cable. 2. Remove the left foot cooler outlet assembly at the instrum ent panel attachm ent. 3. Disconnect the switch electrical harness. 4. Remove the switch mounting screws and remove the switch. 5. To install, reverse Steps 1 thru 4 above. RESISTORS Replacement (Fig. IB-49) 1. Disconnect electrical harness at the resistor. 2. Remove the resistor mounting screws and remove the resistor. 3. To install, reverse Steps 1 thru 3 above. BLOWER MOTOR RELAY - G SERIES Replacement (Fig. IB-49) 1. Disconnect electrical harness at the relay. 2. Remove the relay m ounting screw and remove the relay. 3. To install, reverse Steps 1 thru 3 above. CENTER A /C OUTLET - G SERIES Replacement TEMPERATURE DOOR CABLE - G SERIES Replacement Follow Steps 1 thru 10 of "H e a te r A ir D istributor and Extension D uct R eplacem ent" procedure. 11. Disconnect tem perature door control cable at heater case. 12. Disconnect tem perature door control cable at control. 13. M ake up new cable. 14. To reassemble, Reverse Steps 1 thru 13. CONTROL - G SERIES 1. 2. 3. 4. 5. 6. 7. 8. 9. Disconnect negative battery cable. Remove engine cover (R efer to Section 6A). Remove steering column to I.P. attaching screw. Remove radio support bracket screw. Remove I.P. attaching screws. Pull right side of I.P. rearw ard. Remove duct (distributor) attaching screws. Remove center deflector. To replace, reverse Steps 1 thru 8 above. VACUUM LINES-G VAN Replacement Replacement (Fig. IB-48) 1. Disconnect the battery ground cable. LIG H T T R U C K SE R V IC E M AN U AL Vacuum line routing is illustrated in Fig. 1B-52. AIR CONDITIONING IB-49 Fig. lB-47--Air Deflector Outlets (G Series-C60 System) L IG H T T R U C K SERVICE M A N U A L IB-50 AIR CONDITIONING Fig. 1 B-52--Vacuum Harness (G Series) Fig. 1B-53--Condenser Installation-G Series L IG H T T R U C K SE R V IC E M A N U A L AIR CONDITIONING IB-51 Fig. 1B-54--Evaporator Blower Assembly-G Series LIG H T TR U C K SERVICE M A N U A L IB-52 AIR CONDITIONING COMPRESSOR COMPRESSOR ASSEMBLY R IN G HOSE & TUBE ASSEMBLY C O N D . OUTLET A C C U M DEHYDR ASSEMBLY OUTLET PIPE G MOD. V8 ENG. C60/69 HOSE & TUBE ASSEMBLY EVAP. OUTLET REAR V IE W Fig. 1 B-55-Refrigerant Lines - G Series LIG H T T R U C K SE RV IC E M A N U A L G MOD. LE 3 ENG. C60 AIR CONDITIONING IB-53 Fig. 1B-56--Refrigerant Lines-Condenser Inlet 6 Cyl Engine TEMPERATURE DOOR CABLE Tem perature cable attachm ent and routing is shown in Fig. IB-65. VACUUM TANK - G SERIES (Fig. IB -60 & IB-61) Replacement 1. Raise the hood. 2. Disconnect the vacuum harness at the tank. 3. Remove the tank attaching screws and remove the tank. 4. To install, reverse Steps 1 thru 3 above. CIRCUIT BREAKER The entire air conditioning system is protected by a 45 am p circuit breaker located on the left side of the dash, in the engine com partm ent. A /C DUCTWORK A ir C onditioning duct attachm ent is shown in Fig. 1B63. OVERHEAD SYSTEM-G SERIES This system is used in conjunction with the C60 system. DEFROSTER DUCT D efroster duct m ounting is shown in Fig. 1B-64. The G Van C69 system is almost identical to the C-K M odels overhead system R efer to CK Series overhead system service procedures. LIG H T T R U C K SERVICE M A N U A L IB-54 AIR CONDITIONING LIG H T T R U C K SERVIC E M A N U A L AIR CONDITIONING IB-55 LIG H T T R U C K SERVICE M A N U A L IB-56 AIR CONDITIONING Fig. 1B-64--Defroster Duct-G Series DASH MOUNTED SYSTEM-MOTOR HOME CHASSIS This system is installed on the vehicle and checked at assembly. The blow er-evaporator is then disconnected and shipped with the chassis unit to the body supplier. For this reason, it will only be possible to give basic replacem ent procedures on some components. CONDENSER Replacement (Fig. IB-66) 1. Disconnect the battery ground cable. 2. Purge the system of refrigerant. LIG H T T R U C K SERVIC E M A N U A L AIR CONDITIONING IB-57 Fig. 1B-66--Condenser (Motor Home Chasis Unit) 3. Disconnect the condenser inlet and outlet lines and cap or plug all open connections at once. 4. Remove the condenser to radiator support screws and remove the condenser. 5. To install a new condenser, reverse Steps 1 thru 4 above. A dd one fouid ounce of clean refrigeration oil to a new condenser. NOTICE: Use new " O " rings, coated with clean refrig­ eration oil, when connecting all refrigerant lines. 6. Evacuate, charge and check the system. RECEIVER-DEHYDRATOR Replacement (Fig. IB-67) 1. Disconnect the battery ground cable. 2. Purge the system of refrigerant. 3. Disconnect the inlet and outlet lines at the receiverdehydrator and cap or plug the open lines a t once. 4. Rem ove th e receiv er-d eh y d rato r b rack et a ttac h in g screws and rem ove th e b ra c k e t and receiverdehydrator. 5. To install a new receiver-dehydrator, reverse Steps 1 th ru 4 above. Add one fluid ounce of clean refrigeration oil to a new receiver-dehydrator. Unit) 2. Remove the sight glass retainer nut using a screwdriver and remove old glass and " O " ring seal. 3. Install the new glass and seal and retainer nut, being careful not to turn the nut past the face of the housing. To do so may dam age the "O " ring seal. 4. Evacuate, charge and check the system. BLOWER-EVAPORATOR ASSEMBLY (Fig. IB-69) Removal 1. Disconnect battery ground cable. 2. Purge system of refrigerant. 3. Disconnect inlet and outlet refrigerant lines from the back of unit. C ap or plug all open connections at once. 4. Disconnect drain tubes from evaporator case. 5. D isconnect electrical connector from com pressor. Remove the term inal (R efer to Fig. IB-70) and allow connector to hang on ground wire. 6. Rem ove screws securing grom m et retain e r to dash panel. Remove wire from grom m et through slit. 7. Disconnect electrical lead at connector. 8. Remove unit m ounting bolts. Remove unit from vehi­ cle, carefully pulling com pressor electrical lead through dash panel. NOTICE: Use new " O " rings, coated with clean refrig­ eration oil, when connecting all refrigerant lines. 6. Evacuate, charge and check the system. SIGHT GLASS REPLACEMENT Once the unit has been removed from the vehicle, continue with com ponent replacem ent as follows: BLOWER ASSEMBLY Removal (Fig. IB-71) If dam age to the sight glass should occur, a new sight glass kit should be intalled. The kit contains the sight glass, seal and retainer. (R efer to Fig. IB -68). 1. Purge system. 1. Remove the cover plate and separate the upper and lower case halves. Remove blower motor m ounting strap screw and remove strap. LIG H T T R U C K SERVICE M A N U A L IB-58 AIR CONDITIONING Fig. lB-68--Sight Glass Replacement TERMINAL SCREW DRIVER (NARROW BLADE) CONNECTOR TANG GROOVE A. Insert screw driver in groove & press tang toward terminal to release. B. Pry tang back out to insure locking when reinstalled into connector. Fig. 1B-69--Blower-Evaporator (Motor Home Chassis Units) 2. Remove blower assembly. Remove the wheels from the m otor shaft. Installation 1. Install the blower wheels on the motor so th a t the lower blades curve tow ard the dash panel side of the unit when the m otor is placed in the case as shown in Fig. IB-85. 2. Place th e m otor in th e b ra c k e t w ith th e electrical connector side of the m otor to the right side of the L IG H T T R U C K SE RV IC E M A N U A L Fig. 1B-70--Terminal Removal bracket. A tta ch the m ounting strap . Align blow er wheels so th at they do not contact case. 3. Assemble the case halves and attach the cover plate. 4. Reverse Steps 1-8 on the " Blower-Evaporator Assem­ bly" removal procedure. 5. Evacuate, charge and check the system. AIR CONDITIONING AIR SENSING CAPILLARY CORRECT BLOWER BLADE ANGLE IB-59 THERMOSTATIC SWITCH Fig. 1B-73--Thermostatic and Blower Switches 3. Remove evaporator core retaining screws and remove core. Fig. 1 B-71--Blower Assembly (M o to r Home Chassis 4. R e m o v e b lo w e r m o to r a n d h a rn e s s a s s e m b ly fr o m case. Unit) Installation 1. Reverse applicable steps in the removal procedure. T HERM O STA TIC SW IT C H CAPILLARY TUBE SCR EEN M E SH NOTICE: Use new " O " rings coated with clean refriger­ ation oil when connecting lines. Add 3 oz. of new refrigeration oil to a new core. 2. Reverse steps 1 thru 8 of the "Blower Evaporator Assem bly" removal procedure. 3. Evacuate, charge and check the system. THERMOSTATIC AND/OR BLOWER SWITCHES Replacement 1. Remove the cover plate assembly from the evaporator case. BUMPER E X P A N S IO N V A LV E Fig. 1 B-72--Expansion Valve (M otor Home Chassis Unit) EXPANSION VALVE, EVAPORATOR AND/OR EVAPORATOR CASE Removal (Fig. IB-72) 1. Remove the cover plate and separate upper and lower case halves. 2. Remove inlet and outlet lines from the expansion valve. R em ove sensing bulb from th e evap o rato r o utlet m anifold. Remove expansion valve. C ap or plug open connections at once. 2. Remove two screws securing either switch to the cover plate and remove appropriate switch (Fig. 1B-73). 3. Install replacem ent switch, reinstall cover plate and reverse steps 1-8 of the " Blower-Evaporator Assem ­ bly" removal precedure. W hen installing therm ostatic switch, be sure to position sensing capillary as when unit was removed. RESISTOR The blower motor resistor is located on the top of the unit. The entire unit m ust be removed to replace the resistor. FUSE This U nit does not incorporate an in-line fuse. The lead w ire is connected to the H eater W iring H arness and operates off the 20 am p H eater Fuse. LIG H T T R U C K SERVICE M A N U A L IB-60 AIR CONDITIONING SPECIFICATIONS A IR C O N D IT IO N IN G Compressor T y p e ......................................... 4 Cylinder Radial Displacement 6 Cylinder Axial • 4 Cylinder Radial • • • R o t a t i o n ............................. Volts ........................1 2 .6 Cu. In. ....................... 1 0 .0 C u .ln . Amps. (Cold) RPM (Cold) Blower M otor C-K Four Season . . 12.0 C-K-G Overhead, G Floor and M otor Home U n its .................... 12.0 12.8 Max. 13.7 M ax. 3400 Min. 3400 M in. Compressor Clutch Coil Ohms (at 8 0 ° F ) ..................... ...................................... 3.70 Amps, (at 8 0 ° F ) ..................... ................. 3.33 @ 1 2 volts Torque Specifications Compressor Suction and Discharge Connector B o l t ................................... Rear Head to Shell Stud Nuts ( 6 Cyl.) Shaft Mounting N u t (6 C y l . ) ............... Shaft Mounting Nut (4 Cyl.) . . . High Pressure Relief Valve (6 Cyl.) Oil Charge Screw (6 Cyl.) . . . . Air Gapon Clutch (6 C y l.) . . . . Compressor Mounting Bracket Compressor to Front Bracket Bolts Belt Tension ......................................... Fuse Block— C-K S y s te m s ........................................... M o tor Home Chassis U n it..................... In -L in e C-K S y s te m s ........................................... M o tor Hom e Chassis U n i t .................... Circuit Breaker G Model Systems..................................... LIG H T T R U C K SE R V IC E M A N U A L ............23 ft. lbs. ............ 20 ft. lbs. . . . . . 8-12 ft. lbs. . 12 ft. lbs. . . . 25 ft. lbs. See Tune-Up Chart .... 20 Amp. . . . . 25 Amp. ............... None .... 45 Am p. AIR CONDITIONING IB-61 SPECIAL TOOLS 1. J-25030 Clutch Hub Holding Tool 2. J-25029 Rotor Bearing Remover and Rotor Assy. Installer 3. J-24895 M ain Bearing Installer 4. J-24896 M ain Bearing Remover 5. 6. 7. 8. J-25031-2 J-25031-1 J-25008-1 J-25008-2 Rotor and Bearing Puller Rotor and Bearing Puller G uide Compressor H olding Fixture Shell Installing Fixture Fig. 1B-74--Air Conditioning Special Tools LIG H T T R U C K SERVICE M A N U A L IB-62 AIR CONDITIONING SPECIAL TOOLS 1. J -8 3 9 3 2. J -2 4 0 9 5 3. J -54 5 3 4. J -9 4 5 9 J -2 5 4 9 9 5. J -5 4 2 0 J -2 5 4 9 8 6. J -6 0 8 4 C h a rg in g Station O il Inducer G o ggles 7 /1 6 " -2 0 9 0 ° G a u g e Line 3 /8 " -2 4 A d a p te r 7 /1 6 " -2 0 S tra ig h t G a u g e Line 3 /8 " A d a p te r Leak Detector 7. J -8 4 3 3 8. J -9 3 9 5 9. J -2 3 5 9 5 Puller Puller Pilot R efrig era n t C an V alve 10. J -6271-01 (S id e -T a p ) R efrig era n t C an V alve (To p-Tap) 11. J -5 4 2 1 -0 2 Pocket Thermometers (2) 12. J-54 0 3 13. J -64 3 5 14. J -9 3 9 6 N o. 21 S nap Ring Pliers N o. 26 S nap Ring Pliers Compressor H old ing Fixture Compressing Fixture Clutch H ub H old ing Tool 9 /1 6 " Thin W a ll Socket H ub and Drive Plate 15. J -2 5 0 3 0 16. J-94 0 3 17. J -9 3 9 9 18. J-9401 19. J-94 8 0 -01 20. J -93 9 2 21. J -2 3 1 2 8 Assembly Remover H ub and Drive Plate Assembly In staller S eal Remover S eal S eat Remover Fig. lB-75--Air Conditioning Special Tools LIG H T T R U C K SE RV IC E M A N U A L 22. 23. 2 4. 2 5. J-93 9 8 J-9481 J-80 9 2 J -21 3 5 2 2 6. J -51 3 9 2 7. J-94 3 2 28. J-95 5 3 -01 29. J -2 1508 3 0. J -2 2 9 7 4 3 1. J-96 2 5 32. J-94 0 2 Pulley B earing Remover Pulley a nd B earing In sta ller H a n d le In tern a l Assembly Support Block O il Pickup Tube Remover N e e d le B earing Installer Seal S eat " O " Ring Remover S eal S eat " O " Ring In staller S haft Seal Protector Pressure Test C onnector Parts Tray FRAME 2A-1 SECTION 2A FRAME CONTENTS G eneral Description ................... ......................................................................2A-1 On Vehicle S ervice........................................................................................... .2A-1 M aintenance and Inspection........................................................................ .2A-1 U nderbody In sp ectio n................................................................................. .2A-1 F ram e Inspection.......................................................................................... .2A-1 Fram e A lig n m en t.............................................................................................2A-1 U nderbody A lignm ent......................................................................................2A-4 Excessive Body D am age................................................................................ ..2A-4 GENERAL DESCRIPTION L ig h t d u ty 10-30 Series fram es are of th e ladder channel section riveted type. Figure 2A-1 thru 2A-4 illustrates typical light duty truck fram es with crossm embers, body mounts and suspension attaching brackets. This section also includes general instructions for checking fram e alignm ent and recommendations on fram e repair. The G -Van fram e side rails, cross sills and outriggers are part of the underbody assembly which is a welded unit. M isalignm ent of the underbody can affect door opening fits and also influence the suspension system , causing suspension m isalignm ent. It is essential, th erefo re, th a t underbody alignm ent be exact to within - 1/16 in. (1.9m m ) of the specified dimensions. ON VEHICLE SERVICE MAINTENANCE AND INSPECTION UNDERBODY INSPECTION Raise the vehicle on a hoist (preferably a twin-post type). C heck for obvious floor pan deterioration. C heck for loose dirt and rust around the inside of the floor pan reinforcem ent m em ber access holes. This is the first indication th a t corrosion m ay exist in hidden areas, and th at repairs m ight be required before the final cleaning and protective treatm en t is perform ed. Using a chisel, ensure th at the drain provisions in the floor pan reinforcem ent m em bers are open. T here are drain holes in the body side panels also. These holes can be opened by using a punch or drift. The side panel drain holes are in the rear section of the rocker panels, and in the lower rear q u arter panels. FRAME INSPECTION R aise the vehicle on a hoist (preferably a twin-post type). Check for obvious floor pan deterioration. Check for loose dirt and rust around the inside of the fram e rails, on top and at the ends where corrosion m ay exist in hidden areas. Check especially in the fram e box sections for accum ulation of debris. FRAME ALIGNMENT Horizontal fram e checking can be made with tra m ­ ming gages applied directly to the fram e or by transferring selected points of m easurem ent from the fram e to the floor by means of a plum bob and using the floor layout for measuring. Fig. 2A-2 or 2A-4 may be used as a general guide in the selection of checking points; however, selection of these points is a rb itrary depending on accessibility and convenience. An im portant point to rem em ber is th at for each point selected on one side of the frame, a corresponding point on the opposite side of the frame m ust be used for vertical checks, opposite and alternate sides for horizontal checks. Vehicle Preparation Points to rem em ber when preparing vehicle for fram e checking: 1. Place vehicle on a level surface. 2. Inspect dam aged areas for obvious fram e misalignm ent to elim inate unnecessary measuring. 3. Support vehicle so th at fram e sidemembers are parallel to the ground. Tramming Sequence (Fig. 2A-1) 1. Dimensions to bolts an d /o r holes in fram e extend to dead center of the hole or bolt. 2. Dimensions m ust be within 3/16 in. (4.7 mm). 3. If a tram bar is used, for horizontal alignm ent " X " check from opposite and alternate reference points AA, BB and CC, as illustrated by the lines in Fig. 2A-1. 2A-2 FRAME Error will result if a tram b ar is not level and centered at the reference points. 4. O btain vertical dimensions and com pare the differences betw een these dim ensions w ith th e dim ensions as shown in Fig. 2A-3 or 2A-4. Horizontal Check 1. M easure fram e width at front and rear. If widths correspond to specifications, draw centerline full length of vehicle halfway between lines indicating front and rear widths. If fram e widths are not correct, layout centerline as shown in Step 4. 2. M easu re d istan ce from cen terlin e to corresponding points on each side of fram e layout over entire length. Opposite side m easurem ent should correspond within 3/16 in. (4.7 mm). 3. M easure diagonals m arked A, B and C. If the lengths of intersecting diagonals are equal and these diagonals intersect the centerline, fram e area included between these points of m easurem ent may be considered in alignm ent. 4. If front or rear end of fram e is dam aged and width is no longer within limits, fram e centerline m ay be drawn through the intersection of any two previously drawn pairs of equal, intersecting diagonals. Vertical Check Vertical dimensions are checked with a tram m ing bar from indicated points on the fram e (Figs. 2A-2 and 2A-4). For example, if the tram bar is set a t point B with a vertical pointer length of 8-1/4 in. (206 m m ), and a t point E with a vertical pointer length of 5-1/4 in. (131 mm ) (a height difference of 3 in. (75 m m ), the tram bar should be parallel with the fram e. If the area is tw isted or m isaligned in any way, tram bar will not be parallel. Placing the tram bar vertical pointers on opposite sides of the fram e side rail is preferable in th at fram e twist will show up during this vertical check. Fig. 2A-2 and 2A-4 show typical checking points, with dimensions for various fram es shown in Fig. 2A3. Frame Repair Welding Before welding up a crack in fram e, a hole should be drilled at the starting point of the crack to prevent spread­ ing. W iden V groove crack to allow com plete weld penetration. NOTICE: Do not weld into corners of fram e or along edges of side rail flanges. W elding at these points will tend to weaken the fram e and encourage new cracks. Fig. 2A-1--Frame Horizontal Checking-Typical ■v Vjf*, FRAME Model A B C D E F G H 1 J K L M N P R S 2A-3 T U V 14 CA107 13-3/8 15-1/4 16 19-7/8 12 13 10 14-7/8 17-3/4 17-3/4 19-7/8 16-3/4 15-5/8 17 3/4 68-1/2 76-1/2 110 16-7/8 16-7/8 CA109 13-3/8 15-1/4 16 19-7/8 12 13 10 14-7/8 17-3/4 17-3/4 19-7/8 16-3/4 15-5/8 17-3/4 69-5/8 86-1/2 120 16-7/8 16-7/8 14 CA209 13-3/8 15-1/4 17 19-7/8 12 13 10 14-7/8 17-3/4 17-3/4 19-7/8 16-3/4 15-5/8 17-3/4 69-5/8 86-1/2 120 16-7/8 16-7/8 14 CA210 310 13-3/4 15-1/4 16 18-1/2 10 13 10 14-1/4 17-3/4 17-3/4 19-7/8 15-5/8 17-3/4 68-3/4 105 131 16-7/8 16-7/8 14 CA314 13-3/8 14 7/8 16 18-1/2 10 13 10 14-1/4 17-3/4 17-3/4 19-7/8 15-5/8 17-3/4 69-7/8 129 155-1/2 16-7/8 16 7/8 14 KA107 13-3/8 15-1/4 17 19-7/8 12-1/2 13 10 14-7/8 17-3/4 17-3/4 19-7/8 16-3/4 15-5/8 17-3/4 68-1/2 76-1/2 110 16-7/8 16-7/8 14 KA109 209 13-3/8 15-1/4 17 19-7/8 12-1/2 13 10 14-7/8 17-3/4 17-3/4 19-7/8 16-3/4 15-5/8 17-3/4 68-1/2 86-1/2 120 16-7/8 16-7/8 14 PA 100 7-5/8 9-3/8 11 14-5/8 9-1/2 13 10 PA208 308 7-5/8 9-3/8 11-5/8 14-5/8 9-1/2 13 10 9-1/2 PA210 310 7-5/8 9-3/8 11-5/8 14-5/8 9-1/2 13 10 9-1/2 9-1/2 13 10-7/8 13 71-7/8 36 89 16-7/8 16-7/8 14 13 9-1/2 13 10-7/8 13 72-1/4 59 131 16-7/8 16-7/8 14 9-1/2 13 9-1/2 13 10-7/8 13 71-7/8 67 153 16-7/8 16-7/8 14 9-1/2 13 10-7/8 PA314 7-5/8 9-3/8 11-5/8 14-5/8 13 10 9-1/2 13 10-7/8 10-7/8 13 71-7/8 91 177 16-7/8 16-7/8 14 CA105 13-3/8 15-1/4 17 19-7/8 12 13 10 14-1/4 20 17-3/4 15-5/8 17-3/4 69-5/8 46 88 16-7/8 16-7/8 14 KA105 13-3/8 15-1/4 17 19-7/8 12-1/2 13 10 14-1/4 20 17 3/4 15-5/8 17 3/4 69-5/8 46 88 16-7/8 16-7/8 14 9-1/8 11-1/2 10-7/8 9-1/2 13 10 9-1/2 13 9-1/2 13 10-7/8 10-7/8 13 68-1/2 71 157 16-7/8 16-7/8 14 9-1/8 11-1/2 10-7/8 9-1/2 13 10 9-1/2 13 9-1/2 13 9-7/8 10-7/8 13 68-1/2 92-1/2 178-1/2 16-7/8 16-7/8 14 9-1/8 11-1/2 10-7/8 9-1/2 13 10 9-1/2 13 9 1/2 13 10-7/8 10-7/8 13 68-1/2 112 240-3/16 16-7/8 16-7/8 14 PE 31132 (137) PE 31432 (157) PE 31832 Fig. 2A-3--C-K-P Series Frame Reference Dimensions LIG H T T R U C K SERVICE M A N U A L 2A-4 FRAME Fig. 2A-4--G Van Truck Reference Dimensions Bolting W herever rivets or failed bolts are replaced, bolt hole m ust be as near the O.D. of the bolt as possible to prevent bolt from working and wearing. Drill out and line ream hole (or holes) to the bolt O.D. UNDERBODY ALIGNMENT O ne m ethod of d eterm in in g th e alig n m en t of the underbody is with a tra m gage which should be sufficiently flexible to obtain all necessary m easurem ents up to three quarters the length of the vehicle. A good tram m ing tool is essential for an aly zin g and d eterm in in g th e extent of collision m isalignm ent present in underbody construction. MEASURING To m easure the distance accurately between any two reference points on the underbody, two specifications are required. 1. The horizontal dim ension between the two points to be tram m ed. L IG H T T R U C K SERVICE M A N U A L 2. The vertical dimension from the datum line to the points to be tram m ed. The tram bar should be on a parallel to th at of the body plane. The exception to this would be when one of the reference locations is included in the misaligned area; then the parallel plane between the body and the tram bar may not prevail. A fter completion of the repairs, the tram gage should be set a t the specified dim ension to check the accuracy of the repair operation. EXCESSIVE BODY DAMAGE If dam age is so extensive th at key locations are not suitable as reference points, repair operations should always begin with the underbody area. All other components should be aligned progressively from this area. Unlike the conven­ tional type of fram e design, th e unitized type of body construction seldom develops the two conditions of "tw ist" and "diam ond" in the underbody area as a result of front or rear end collisions, therefore, there usually is an undam aged area suitable as a beginning reference point. BUMPERS 2B-1 SECTION 2B BUMPERS NOTICE: Fasteners are im portant attaching parts in th a t they could affect the perform ance of vital compo­ nents and systems, an d /o r could result in m ajor repair expense. They m ust be replaced with one of the same part num ber or with an equivalent part if replacem ent becomes necessary. Do not use a replacem ent part of lesser quality or substitute design. Torque valves must be used as specified during reassembly to assure proper retention of these parts. For prevailing torque nut(s) and bolt(s), refer to the "R euse of Prevailing Torque N ut(s) and B olt(s)" chart in Section 10. CONTENTS G eneral D escription.............................................................2B-1 Service Procedures - 10 th ru 30 series.......................... ..2B-1 Front Bum per - C, K and P M o d els..............................2B-1 R ear Bum per - C and K M odels.................................. ..2B-1 R ear Step Bumper - C and K M odels........................ Front Bumper G S e rie s.................................................. R ear Bumper G S e rie s ................................................... R ear Step Bumper G S eries.......................................... 2B-2 2B-2 2B-2 2B-3 GENERAL DESCRIPTION All truck front and rear bumpers are of a single piece design. Bumper attachm ents are the standard bracket and brace to fram e mountings. This section contains procedures for the removal and installation of face bar, brackets, braces and license plate brackets. SERVICE PROCEDURES-10 THRU 30 SERIES FRONT BUMPER-C, K AND P MODELS Installation Removal Fig. 2B-1, 2B-2 Assem ble and install front bum per following the removal procedure in reverse order. 1. Remove bolts securing two bum per brackets to frame. 2. Remove bolts securing bum per face bar to fram e, and left and right bum per braces and remove bum per from vehicle. 3. If necessary, disassemble bum per by removing bolts attaching brackets and braces to bum per face bar. 4. If equipped with bumper guards (Fig. 2B-2) remove rem aining nuts and bolts. REAR BUMPER-C AND K MODELS (FIG 2B- 3) Removal 1. Remove bolts attaching bum per to each bum per brace. Disconnect license lamp wiring on suburban and panels and pickup. 2. Remove bolts attaching bum per to frame. 3. Remove bum per from vehicle. LIG H T T R U C K SERVICE M AN U AL 2B-2 BUMPERS 4. If necessary, replace body splash shield. Installation Install rear bum per following removal procedure in reverse order. C onnect license lam p wiring on suburban panel, and pickup models. REAR STEP BUMPER C AND K MODELS Removal (Fig. 2B-4) Removal Fig. 2B-5, 2B-6 1. Remove nuts securing bum pers to brackets and braces from left and right side. Remove bum per. 2. If necessary to remove the braces and brackets, remove screws securing brackets and braces to sheet metal. 3. If equipped with bum per guards (Fig. 2B-6) they may be removed from the face bar at this time. Installation Reverse removal steps to install bum pers. 1. Disconnect license lam p wiring. 2. Remove bolts connecting bum per to braces. 3. Remove bum per assembly. 4. Remove bolts securing bum per brace to fram e and remove brace. Installation Install rear step bum per by reversing removal proce­ dure. C onnect license lam p wiring. FRONT BUMPER - G MODELS L IG H T T R U C K SE RV IC E M A N U A L REAR BUMPER-G MODELS Removal Fig. 2B-7, 2B-8 1. Remove nuts securing bum per to brackets and braces and remove the bumper. 2. Remove the license plate support nut and bolts. 3. Remove brackets and braces from vehicle. The bum per may be removed with brackets and braces attached if necessary. Installation Install in reverse order of removal. BUMPERS 2B-3 SPECIFICATIONS TORQUE SPECIFICATIONS C, P AND K Front Bumper .........................................................35 ft.-lbs. Front Bumper Bracket and Brace ........................ 70 ft.-lbs. Rear Bumper to Outer Bracket ............................ 35 ft.-lbs. Rear Bumper Outer Bracket and Brace .............. 50 ft.-lbs. License Plate Bracket.............................................18 ft.-lbs. Gravel Deflector ...................................................85 in.-lbs. Rear Step Bumper to Bracket or Frame .............. 40 ft.-lbs. TORQUE SPECIFICATIONS G Front Face Bar to Bracket .................................... 24 ft.-lbs. Bracket to Cross S ill...............................................24 ft.-lbs. License Plate Bracket to Face Bar .................... 100 in.-lbs. Rear Face Bar to Brackets.....................................55 ft.-lbs. Bracket to Floor .....................................................55 ft.-lbs. Fig. 2B-ST--Specifications LIG H T T R U C K SERVICE M A N U A L CHASSIS SHEET METAL 2C-1 SECTION 2C CHASSIS SHEET METAL N O TIC E Fasteners are im portant attaching parts in th at they could affect the perform ance of vital components and systems, an d /o r could result in m ajor repair expense. They m ust be replaced with one of the same part num ber or with an equivalent part if replacem ent becomes necessary. Do not use a replacem ent part of lesser quality or substitute design. Torque valves m ust be used as specified during reassembly to assure proper retention of these parts. For prevailing torque nut(s) and bolt(s), refer to the "R euse of Prevailing Torque N u t(s) and B olt(s)" chart in Section 10. CONTENTS G eneral D escription............................................................ On Vehicle S erv ice............................................................. Hood Assem bly - CK S e rie s ......................................... Cowl Top Vent P a n e l.................................................... Hood H inge R eplacem en t............................................ Hood H in g e ..................................................................... Hood Lock M ech an ism ................................................ Hood A ssem bly............................................................... Hood Assembly - G S eries................................. ........... Hood H in g e ..................................................................... Hood Lock A ssem b ly .................................................... 2C-1 2C-1 2C-1 2C-1 2C -2 2C -2 2C -2 2C -2 2C -2 2C-3 2C -3 Hood B u m p er................................................................. Front Sheet M etal - CK S eries.................................... R adiator S u p p o rt........................................................... Front Fender................................................................... Front Fender and S k ir t............................................... Front Fender S k ir t........................................................ Running B o a rd ............................................................... Fender Skirt - P S eries................................................... Adhesive Bodyside Molding (All Vehicles)............... Wood G rain Applique Installation Procedure.......... Decal Applique Procedure (All V ehicles)................. Specifications...................................................................... 2C-3 2C -5 2C-7 2C-8 2C-8 2C-8 2C-8 2C-8 2C-8 2C-9 2C-10 2C-11 GENERAL DESCRIPTION CK MODELS The chassis sheet metal assembly is attached to the fram e and body at adjustm ent points. The front of the assembly is supported by two mounts located at the fram e side rails. Fore and aft and side adjustm ent is allowed by oversize holes at the fender rear attaching point and chassis sheet m etal mounts. Special shims at the rear locations allow adjustm ent of the rear of the assembly. The lower rear edge of the assembly is attached to the body at the rocker panel by bolts on each side. Shims are used at this location to provide in and out adjustm ent at the rear of the fender. The bolts th a t retain the sheet m etal braces m ust be torqued to the required torques. If these bolts are loose, the braces will not provide additional support for the sheet m etal assembly. these items are welded together as an integral part of the body. Front end sheet m etal includes the hood assembly, hood hinges, hood lock catch and support, a hood rod assembly which supports the hood, a bolted radiator-upper tie bar, and series designation plates and hoods emblems. Anti-Corrosion Information "Anti-corrosion m aterials have been applied to the interior surfaces of some m etal panels to provide rust resistance. W hen servicing these panels, areas on which this m aterial has been disturbed should be properly recoated with service-type anti-corrosion m aterial." G MODELS The front end sheet m etal design does not include the radiator support and fenders as loose items inasmuch that ON VEHICLE SERVICE HOOD ASSEMBLY - CK MODELS 2. Open hood and remove two screws at each wiper nozzle attachm ent. Cowl Top Vent Panel (Fig. 2C-1) 3. Remove four screws at front of cowl panel. Replacement 1. Remove wiper arms. 4. Pry the five plastic fasteners loose from windshield frame. Remove the panel. 5. Reverse the above listed procedure to replace. LIG H T T R U C K SERVICE M A N U A L 2C-2 CHASSIS SHEET METAL 5. Remove two bolts hinge to rear reinforcem ent at the body and remove hinge. 6. Replace by reversing the above procedure. Hood Lock Mechanism The hood latch assembly and bracket are mounted to the R adiator Support. Elongated holes in the bracket are provided for alignm ent purposes. A sep a ra te secondary latch is mounted to the striker plate in the hood. See Fig. 2C-3 and 2C-4. Replacement 1. Open hood and remove the two bolts holding the hood latch to the bracket. If original hood lock assembly is to be replaced, scribe a line around lock for alignm ent on installation. 2. Replace hood latch assembly and bolts loosely. 3. Align within scribe m arks and tighten bolts. TYPICAL 2 PLACES Fig. 2C-l--Cowl Top Vent Panel Hood Bumper Adjustment Hood Bumpers m ust be adjusted until hood and fender line up flush at front corner. Hood Assembly Removal 1. Open hood and prop in full open position. If hood is to be reinstalled and present alignm ent is satisfactory, m ark each hinge in relation to hood, to assure original alignm ent. Hood Hinge (Fig. 2C-2) Replacement 1. Prop the hood in the extrem e open position and place protective covering over the cowl and fenders. Scribe position of hinge attach m en t to hood. 2. Remove two bolts link assembly to hood and two bolts at hinge to the hood. 3. Rem ove two bolts link assem bly to fender inner, remove link. 4. Remove wiper arm s and a t the cowl cover panel remove four screws and lift up w ithout removing for access. L IG H T T R U C K SE RV IC E M A N U A L CHASSIS SHEET METAL 2C-3 m ounted strik er plate, preventing upw ard or dow nw ard m ovem ent of the hood while the vehicle is in m otion. Integral with the strik er plate is the com bination lock release lever and safety catch. 1. S cribe a line around the entire hinge plate to be repositioned. 2. Loosen the appropriate screws and shift the position o f the hood into correct alignm ent using the scribe m arks to check am ount of movement. Check alignm ent by tightening screws and closing the hood. Replacement 1. Open hood and remove the four bolts holding the com bination lock catch and lock bolt. If original hood lock assembly is to be replaced, scribe a line around lock for alignm ent on installation. 2. Place hood lock assembly in position. 3. A djust as outlined under A djustm ents. Adjustment 2. Remove two (2) cap screws which attach each hinge and link to hood; then with a helper remove hood from vehicle. Installation 1. If original hood is to be installed, position hood to hinges and links and install four cap screws snug which attach hinges and links to hood. If a new hood is to be installed, perform procedures as outlined under Alignm ent, directly below. 2. Shift hood on hinges to location m arks m ade before removal of hood, then tighten attaching cap screws at hinges firmly. Close hood and check fit. If necessary to align hood perform p rocedure as outlined under "A lignm ent" which follows. Hood lock assembly to be adjusted fore and aft until hood lock bolt enters center of elongated guide. Bending bolt to accomplish this adjustm ent may seriously effect lock operation and safety catch engagem ent and is, therefore not recommended. 1. A djust lock bolt as shown in Fig. 2C-7. 2. Open hood and adjust tightness of catch assembly so th at it is ju st "snug" enough to hold lock bolt in position. 3. Close hood in a normal manner. 4. Raise hood again; lock bolt assembly will have shifted to operating position. T ighten bolts fully. F u rth e r ad ju stm en t m ay be m ade a t lock bolt support, if necessary. 5. A djust lock bolt to obtain a secure hood closure and reasonable lock release effort. Alignment 1. Loosen hood hinge bolts. N ote th at the rear most bolt holes in hinge are slotted to allow hood to move back and forth. 2. A djust bracket at hood latch, as necessary. Slotted hole in the bracket allow movement up or down a t the latch, and right or left a t the radiator support. 3. A djust hood bum per as necessary in proportion to the latch. Hood Assembly - G Model The alignm ent of the hood is controlled by the position of the hood hinges and the height of the two bum pers located one at each side of the radiator support. The adjustm ent at the hood lock m ust be m ade after the hinges and bumpers are properly adjusted (R efer to Hood Lock A djustm ent Fig. 2C-7). To align the hood and lock proceed as follows: Hood Hinge (Fig. 2C-5) Hood Lock Assembly - G Model A bolt-type hood lock is used as shown in Fig. 2C-7. T he lock bolt, located on th e hood, dovetails w ith the Fig. 2C-5--Hood Hinge-G Model LIG H T T R U C K SERVICE M AN U AL 2C-4 CHASSIS SHEET METAL HOOD EMBLEM - CK MODELS (FIG. 2C-9) Hood Bumper Adjust hood bumpers so that hood top surface is flush with the fender and grille top surfaces. Hood Assembly-G Model (Fig. 2C-7) Removal 1. Lay a fender cover along cowl top to prevent hood from scratching painted surfaces. 2. Open hood and prop in full open position. If hood is to be reinstalled and present alignment is satisfactory, mark each hinge in relation to hood, to assure original alignment. 3. Remove two cap screws which attach each hinge to hood; (Fig. 2C-5) then with a helper remove hood from vehicle. Installation Fig. 2C-6--Hood Lock Catch Assembly-G Model 1. If original hood is to be installed, position hood to hinges with helper and install four cap screws snug which attach hinges to hood. 2. Install rod assembly. If a new hood is to be installed, perform procedures as outlined under Alignment, directly below. 3. Shift hood on hinges to location marks made before removal of hood, then tighten attaching cap screws at hinges firmly. Close hood and check fit. If necessary to align hood perform procedure as outlined under "A lignm ent" which follows. Alignment 1. Loosen hood hinge bolts. Note that the rear bolt holes in hinge is slotted to allow hood trailing edge to move up and down. 2. A djust hood bumpers so th a t hood and adjacent surfaces are flush. 3. Perform hood lock a d ju stm e nt as outlined in this section if necessary. Hood Lock Assembly to be adjusted fore and aft until nubble (part of Hood Lock Bolt Support Assembly) enters center of elongated guide (Socket). Bending nubble to accomplish this adjustment may seriously effect lock operation and safety catch engagement and is, therefore, N O T R E C O M M E N D E D . Fig. 2C-7--Hood, Bumpers and Latch-G Model HOOD LATCH CABLE RELEASE - CK MODELS (FIG. 2C-8) Hood Rod Support - G Model Refer to Fig. 2C-10 for removal and installation of hood rod support. Replacement 1 Release the hood from below, using a suitable rod, by pressing on the hood release tab at the right side of the lock assembly. 2. Remove the cable at the lock assembly. 3. Remove hood release handle to kickpad attaching screws. 4. Remove hood release cable. 5. To install, reverse Steps 2 through 4. LIG H T T R U C K SERVICE M A N U A L CARBURETOR OUTSIDE AIR INLET SNORKELS (Fig. 2C-11) Removal 1. Raise hood and remove carburetor air duct from air snorkel by sliding duct rearward. 2. Disconnect the attachment incorporated in the duct attaching the air snorkel to radiator support turn and remove from vehicle. CHASSIS SHEET METAL 2C-5 FENDER ASSEMBLY TIE BAR ASSEMBLY Fig. 2C-10--Hood Rod Support - G Model GRILLE MOLDING - CK, G MODELS (FIG. 2C-14) FRONT SHEET METAL ASSEMBLY-CK SERIES LOWER RADIATOR GRILLE - G MODEL (FIG. 2C12) RADIATOR GRILLE PANEL OR BRACKETS CK, G-MODELS (FIG. 2C-13) Removal of entire front sheet metal assembly including rad iato r involves disassembly of mounts, disconnecting ra d iato r hoses and removal of front bumper. Vehicles equipped with air conditioning a nd/or power steering will require special handling. LIG H T T R U C K SERVICE M AN U AL 2C-6 CHASSIS SHEET METAL Fig. 2C-11--Typical Carburetor Air Inlet Snorkel - CK Model Fig. 2C-13--Grille Panel or Brackets Refer to ap prop riate sections of this m anual for instructions. Shims which are found at various locations should be recorded to ease installation of sheet metal assembly. Removal , - /!- * , - ■ . ,, W* ; wr.SU"**lit-..' 1. Remove bolts at hood hinge and link. Remove hood assembly. 2. Drain radiator and remove radiator hoses. Disconnect oil cooler lines if so equipped. 3. Disconnect wire connectors at the dash and toe panel and wire connector to horn and voltage regulator. 4. Disconnect battery and generator wires. 5. Remove front bumper bolts and remove bumper. LIG H T T R U C K SE RV IC E M A N U A L Fig. 2C-14-- Grille Moldings - CK, G Models CHASSIS SHEET METAL 2C-7 6. Remove bolts attaching fender upper edge to cowl door frame. 7. Remove fan shroud. 8. W orking from u n de rne a th rear of fender, remove attachm ent from each fender at the hinge pillar. 9. Remove bolt from each radiator support mounting. 10. Remove bolts at each fender skirt to cab underbody (Fig. 2C-15). 11. With a helper, remove front sheet metal assembly, with radiator, battery, horn and voltage regulator attached. Installation 1. With a helper place sheet metal assembly in position. Install all bolts loosely to facilitate aligning after complete installation. 2. Install fender bolts at cowl. 3. Install combination bolt and flat washer assembly into each fender reinforcement while inserting shims re­ quired between fender reinforcement and body (Refer to Fig. 2C-16). 4. Install two bolts and shims required at each fender rear lower edge to hinge pillar. 5. Install bolt in each fender skirt to underbody. 6. Install bolts at steering column skirt reinforcement, final torque 25 ft. lb. (33 N-m). 7. Tighten each radiator support mounting bolt 33 ft. lb. (44 N-m). 8. Torque bolts at fender to cowl 25 ft. lb. (33 N-m) 9. Install front bumper. 10. Connect wire connectors at dash and toe panel. Attach generator and regulator wires. 11. Connect upper and lower radiator hoses. Connect oil cooler lines to the radiator on models so equipped. 12. Connect battery and fill radiator. S tart engine and check for leaks. 13. Install Hood. Radiator Support Removal 1. Drain radiator, saving coolant, loosen attachments and remove radiator and coolant recovery tank. 2. Disconnect and remove battery. 3. Remove wiring from radiator support. 4. Disconnect fan shroud and lay back on engine. 5. Remove both head lamp assemblies. 6. Remove grille assembly. 7. Remove lower radiator grille panel. (Fig. 2 C -13). 8. Remove screws securing front fenders to radiator support. 9. Remove screws securing fender skirts to rad iato r support bottom. (Fig. 2 C - 15). 10. Remove bolt securing center support to radiator support. 11. Remove bolts securing hood latch assembly to radiator support. 12. Remove radiator support bolts secured to frame. 13. Tilt radiator support rearward and lift up and off. •! '• Installation 1. Rotate radiator support into position and loosely install attachments to frame. 2. Connect center support to radiator support. 3. Connect hood latch plate. 4. Connect radiator support brackets to fenders. 5. Connect support to fenders. 6. Connect screws from underside of fender skirts to support bottom. 7. A ttach grille lower panel to fenders. 8. Tighten radiator support bolts. 9. Install radiator coolant recovery tank hoses and shroud. 10. Connect removed wiring to radiator support. LIG H T T R U C K SERVICE M AN U AL 2C-8 11. 12. 13. 14. 15. CHASSIS SHEET METAL Install both head lamp assemblies. Tighten all previously installed bolts and screws. Install battery and connect leads and wires. Install grille assembly. Fill radiator with coolant as specified in Section 13. FRONT FENDER (FIG. 2C-16) Removal 1. Remove hood and hinge assembly. 2. Remove head lamp bezel, wiring and attachm ents from fender. 3. Remove screws attaching lower radiator grille panel. 4. Remove screws attaching fender wheel opening flange to skirt. 5. Remove skirt to fender bolts, located inboard on underside of skirt. 6. Remove two (2) screws attaching support bracket to fender. 7. Remove five (5) screws attaching radiator support to front fender. 8. Remove bolt and shim attaching trailing edge of fender to hinge pillar. 9. Remove two bolts and shims at top rear of fender attaching to cowl. Fender Skirt - P Model Installation Refer to figure 2C-18 for removal and installation of fender skirt, brackets, rear supports and hangers. To install, reverse the removal procedure using sealing tape between filler panel and fender. Check sheet metal alignment. ADHESIVE BODY SIDE MOLDING FRONT FENDER AND SKIRT (FIGS. 2C-15 AND 2C-16) Removal 1. Remove hood and hood hinge assembly. 2. Disconnect and remove battery (right side or auxiliary leftside). 3. Remove head lamp bezel, wiring and attachments from fender. 4. Remove screws attaching lower radiator grille panel. 5. Remove screws attaching skirt to radiator support. 6. Remove two (2) top rear fender bolts and shims. 7. Remove bolt and shims at bottom of fender. 8. Remove bolt and shim(s) attaching skirt to underbody. 9. Remove two (2) screw attaching support bracket to fender. 10. Remove five (5) screws attaching radiator support to front fender. 11. Lift fender and skirt from truck. Installation Body side moldings are attached to body panels with foam adhesive tape. To insure a good molding replacement (new or old moldings), the panel surface should be warm (80 to 125°F or 26 to 40°C), clean and free of any wax or oily film residue. Two methods are listed for attaching loose molding ends and completely removed moldings. Molding End Loose 1. Wash affected area with detergent and water and wipe dry. Wipe panel and adhesive side of molding with clean naphtha or alcohol. If molding has separated from adhesive backing (tape remains on body panel), do not remove tape from body. Clean back of molding and tape on body with naphta or alcohol and proceed with step 3. 2. If needed, apply a length of masking tape as a molding guideline. A suitable straightedge may also be used in most cases. 3. Apply adhesive to back of molding and press in place. a. If Loctite 414 adhesive (part no. 1052283) or equivalent is used, apply constant pressure to mold­ ing for 30 seconds or until a firm bond has been established. Install front fender and skirt assembly in reverse order of removal. b. If 3M Super Weatherstrip Adhesive (or equivalent) is used, tape molding in place for 15 minutes. Use naphtha for clean-up. RUNNING BOARDS c. If 3M Plastic and Emblem Adhesive (or equivalent) is used, follow package instructions for apply adhe­ sive and tape molding in place for 30 minutes. Refer to Fig. 2C-17 for removal and installation of running boards. LIG H T T R U C K SERVICE M A N U A L CHASSIS SHEET METAL Molding Completely Removed This method is valid only for moldings attached with adhesive foam tape. If necessary moldings may be rein­ stalled by replacing two-way adhesive foam tape to the molding and then installing the molding to the panel. Twoway adhesive foam tape may be obtained through local jobbers and hardware stores. Use a quality type two-way tape for this application. 1. Wash affected panel area ith detergent and water and wipe dry. Wipe panel and adhesive side of molding with oil-free naphtha or alcohol. If separation occurs between adhesive backing and molding (tape remains on body panel), do not remove tape from body. Clean back of molding and tape with naphtha or alcohol and proceed with step 3. 2. M ark proper alignment position of molding with a length of masking tape. Use adjacent moldings as a guide, if applicable (view A, Fig. 2C-19.) 3. Hold molding in position with cloth or masking tape strips applied every 150 to 200mm (6" to 8 " ) as shown in (view B, Fig. 2C-19.) 4. If body is below 80°F (26°C) due to shop temperature or prior outside temperature, warm body panel witgh heat lamp or heat gun while proceeding with step 5. 5. Loosen top of tape strips holding molding position. Hinge molding downward to gain access to back of molding (view C, Fig. 2C-19), then using a circular motion, quickly apply a thin film of 3M Super W eatherstrip Adhesive (or equivalent) to the adhesive portion of the molding. 6. Align molding to previously installed tape guideline and firmly press in place at once. Hold in place with tape strips. 7. Allow to set 15 minutes. If clean up of cement squeezeout is needed, use a cloth dampened with naphtha; then remove tape strips and tape guideline. 2C-9 Although adhesive cures enought to retain molding after 15 minutes, total cure time is 24 hours. C ar should not be exposed to high pressure car washes, etc., for a 24 hour period. WOOD GRAIN APPLIQUE (INSTALLATION PROCEDURE) General The wood grain applique (transfer film) is a vinyl material with a pressure sensitive adhesive backing. The transfers are serviced in precut panels. The transfers are designed with an appealing wood grain pattern and a 50 degree or semigloss finish. Preparation of the surface to which the transfer will be applied is very important. In cases where body metal repair has been made it is necessary to prime and color coat these areas to blend with the undamaged surface. Apply the transfer film to color coated panels only, never to bare metal or primer. The surface must be free of any imperfections that might high-light through the film. Remove dirt nibs and other foreign material in the paint by light sanding with 600 grit sandpaper. The temperature of the body must be maintained at a moderate level between approximately 70 and 90°F (21 and 32°C). Too warm a body will cause the wood grain film to stick prematurely while too cool a body will reduce the adhesion of the wood grain film. Cool the body panel with cool water when too warm and heat the body panel with a heat gun or a heat lamp when too cold. Transfers should not be replaced in temperatures below 65 0 F (18°C). The transfer should not be subjected to temperature greater than 175°F (79°C) and should not be left at or near this temperature for extended periods of time. Shelf life of the transfer material is 90 days at a temperature not to exceed 105°F (40°C). LIG H T T R U C K SERVIC E M AN U AL 2C-10 CHASSIS SHEET METAL 4. While entire area is still wet with solution, remove paper backing from transfer and align upper edge with pierced holes in fender and press on lightly. 5. Start at center of transfer and squeeze outboard from middle to edges removing all air bubbles and wetting solution to assure a satisfactory bond. Use teflonbacked plastic squeegee only. 6. Notch applique at fender rear contour bend areas with scissors. Also notch out front marker lamp. 7. Fold ends of applique over fender flanges using squee­ gee. Heat the wrap-around area of applique with a heat lamp or gun to approximately 90°F (32°C) and press with squeegee to secure entire edge surface. 8. If the wrap-around of the transfer has trouble sticking to fender edges, brush vinyl adhesive onto the fender or transfer area. Allow the adhesive to set for one minute then press transfer to fender for adhesion. 9. Inspect transfer installation from critical angle using adequate light reflection to detect any irregularities that may have developed during installation. Remove all air or moisture bubbles by piercing each at an acute angle with a fine pin or needle and by pressing the bubble down. 10. Install previously removed parts and clean up vehicle as required. DECAL APPLICATION PROCEDURE (ALL VEHICLES) 1. Wipe clean the entire fender surface, body surface, door ja m flanges, door facings, fender flanges, etce, to be covered with the transfer with a sponge dampened with N aptha or equivalent. 2. Wipe cleaned surface dry with clean cloth. 3. Starting with front fender, cut stripe to length. Allow excess at ends if necessary to avoid handling ends of stripe with fingers. T rim excess before wrapping around or tucking ends. Fig. 2C-19--Molding Application Removal Remove the moldings from the affected panel. The transfer film may then be removed by lifting an edge and peeling the material from the painted surface. Exercise care so as not to damage the paint. Application of heat to the transfer and the panel by means of a heat gun or heat lamp will aid in the removal. Installation 1. With a solvent dampened sponge, clean entire surface to be covered with applique. 2. Wipe area dry with a clean cloth. 3. Prior to application of transfer, wet down the complete transfer surface of the fender with a solution of 1/4 oz. of neutral detergent cleaner (must not contain oils, perfumes, or bleaches) per gallon of clear water. It is essential that no substitute for this solution be used and that the specified proportions be maintained. LIG H T TR U C K SERVICE M A N U A L 4. Remove about 6.00 in. (152.4mm) of the paper backing from stripe and align stripe on vehicle. Fender stripe should bridge the gap at the fender extension, be tucked in with the edge of the squeegee and then trimmed with a razor blade. 5. Pressurize stripe with a soft squeegee or a felt pad. Do not use thumbs or fingers as adequate pressure cannot be applied. 6. Remove the decal backing about 12.00 in. (304.8mm) at a time careful not to touch adhesive with fingers and repeat step no. 5. 7. After complete pressurization, remove the protective premask from the stripes at 180° angle. 8. Repeat above steps no. 4 thru 7 for the doors, quarter panels, and end caps. 9. Fold material around wrap areas, pressurize, heat to approximately 90°F (32°C) with heat gun, and repressurize. 10. Heat all areas at ends of stripes (end caps, front of fender, rear of quarter panel, etc.) 11. Reinspect entire stripe, especially ends and wraps and re- pressurize and heat where necessary to insure entire stripe is down. CHASSIS SHEET METAL 12. Best results are obtained when metal temperature is 70°90°F (21°32°C). Use heat gun or allow cooling time when metal is outside approximate temperature range. 13. The maximum temperature that the tape should be subjected to is 175°F (79°C) (paint repair oven temper­ ature). No tape stripe job should be left in a paint repair oven as damage to the tape may occur. 14. The tape will not be affected by any of the cleaning solvents, waxes or detergents now being used at the assembly plants. Acrylic lacquer solvents will affect the clear coating over the vinyl. 2C -11 1. If the tape is ruined with no paint being removed, the surface should be wiped with a prep-sol to insure a smooth and clean surface. Another section of tape would then be applied according to the application procedure. 2. If a section of paint is removed when the tape is pulled away, the area must be repainted and feathered into the adjoining surfaces. Another section of tape should be applied according to the application procedure. REMOVAL Removal of decal should cause it to be permanently damaged. Test to be conducted at an ambient temperature not to exceed 90°F (32°C) and after a minimum of 72 hours aging. 15. This tape stripe highlights metal imperfections so that all dings and rough metal must be repaired before applying the tape. 16. If after application of stripes, there appears to be bubbles in the surface of the tape stripes, piercing them with an ordinary safety pin will relieve the en- trapped air so that the bubble can be smoothed out. For Large Decals 1. Prior to application of transer, wet down the complete transfer surface with a solution of 0.25 oz. of neutral detergent cleaner (must not contain oils, perfumes, or bleaches) per gallon of clear water. It is essential that no substitute for this solution be used and that the specified proportions be maintained. 2. While entire area is still wet with solution, remove paper backing from transfer, locate and press on lightly. 3. Start at center of transfer and squeegee outboard from middle to edges, removing all air bubbles and wetting solution to assure a satisfactory bond. Use teflonbacked plastic squeegee only. 17. Shelf life of the vinyl tape is 90 days at a maximum temperature of 105°F (40°C). REPAIR Repair is required when: 1. If the tape is damaged. 2. The paint is damaged as the tape is pulled back for realignment or releasing traped air. The following repair procedure is recommended: TORQUE SPECIFICATIONS 27 N- m CK ( 20 ft. G lb s .) Lock to Bracket & Rad. Support Lock Support to Hood Lock Bolt Nut Bumper Bolt Nut Hood Hinge Hood Lock Catch Lock Support to Rad. Support Rad. Support to Frame Rad. Support to Fender Fender Skirt to Fender Fender to Cowl 24 27 17 48 17 17 48 Rad. Grille Panel Lower 17 N- m (150 in . lb s .) N- m N- m N. m N- m N- m N- m N- m ( 18 ( 20 (150 ( 35 (150 (150 ( 35 ft. lb s.) ft. lb s .) in .lb s .) ft. lb s.) in .lb s .) in . lb s .) ft. lb s.) 17 54 17 24 24 24 N* m N- m N- m N- m N- m N- m (150 ( 40 (150 ( 18 ( 18 ( 18 i n .l b s . ) ft. lb s.) i n .l b s . ) ft. lb s.) ft. lb s.) ft. lb s.) LIG H T T R U C K SERVICE M AN U AL BODY 2D-1 SECTION 2D CAB AND BODY N OTICE Fasteners are important attaching parts in that they could affect the performance of vital components and systems, and/or could result in major repair expense. They must be replaced with one of the same part number or with an equivalent part if replacement becomes necessary. Do not use a replacement part of lesser quality or substitute design. Torque valves must be used as specified during reassembly to assure proper retention of these parts. For prevailing torque nut(s) and bolt(s), refer to the "Reuse of Prevailing Torque Nut(s) and Bolt(s)" chart in Section 10. CONTENTS OF THIS SECTION General D escription............................................................................................2D-1 On Vehicle Service..............................................................................................2D-4 C-K M o dels........................................................................................................2D-4 G M odels.............................................................................................................2D-37 Specifications...................................................................................................... ..2D-62 Special Tools.........................................................................................................2D-64 GENERAL DESCRIPTION On the following pages, service procedures will be given for components on all 10-20-30 series trucks in C, K and G models. Reference will be made, both in text and illustra­ tions, to vehicle model lines and to individual model numbers within these model lines. As an aid to identification of specific models, the following general descriptions are given. rear cargo doors. An optional endgate with moveable window is available. Utility Utility vehicle models see figure 2D-4. Are available with a removable roof or a convertible roof. Chassis/Cabs Chassis cab models see figure 2D-1. Two-wheel drive units come in CIO, C-20 and C-30 series. Four-wheel drive units may be either K -10 or K-20. Optional pickup boxes are available. Vans G-Series Vans are available in three models See figures 2D-5 and 2D-6. Vans without body windows and/or passen­ ger seats, sport vans with body windows and passenger seats and commercial cutaway vans as shown in figure 2D-6. Crew Cab/Chassis Crew cab/chassis models see figure 2D-2. Optional pickup boxes are available. Suburban Suburban model see figure 2D-3. Base models have Anti-Corrosion Information "Anti-corrosion materials have been applied to the interior surfaces of some metal panels to provide rust resistance. When servicing these panels, areas on which this material has been disturbed should be properly recoated with service-type anti-corrosion material." LIG H T T R U C K SERVICE M AN U AL 2D-2 BODY Fig. 2D-3--Typical Suburban Model LIG H T T R U C K SERVIC E M A N U A L BODY 2D-3 Fig. 2D-5--Typical Vans and Sport Vans Models LIG H T T R U C K SERVICE M AN U AL 2D-4 BODY ON VEHICLE SERVICE C-K MODELS INDEX Front End Windshield W ip e rs........................................................ .2D-4 Glove B o x ........................................................................ .2D-5 Rear View M irro rs........................................................ .2D-5 Body Glass Windshield G lass..............................................................2D-6 Stationary Body G lass.................................................. ..2D-8 Side Doors A djustm ents.......................................................................2D-10 Front Side D oor.............................................................. ..2D-11 R ep lacem ent......................... ,.................................... ..2D-11 H inges.............................................................................2D-11 V entilator............... ..................................................... ..2D-12 Window and R e g u la to r..............................................2D-13 Locks, Handles, Rods.................................. ............ ..2D-15 W eath erstrip............................................................... ..2D-16 Rear Side D o o rs...............................................................2D-16 R ep lacem en t........................................ ...................... ..2D-16 H inges.......................................................................... .2D-16 Stationary G la s s .................................... .....................2D-16 Window and R egu lato r.............................................2D-17 Locks, Handles, Rods............................................... .2D-18 W eatherstrip............................................................... .2D-19 Rear Doors A djustments.......................................................................2D-19 Locks, Handles, Rods......................................................2D-19 H inges............................................................................... ..2D-19 Gates E n d g a te s .......................................................................... ..2D-21 T a ilg a te s.......................................................................... ..2D-27 Removable Top (Utility).................................................. ..2D-27 Seat Belts................................................................................2D-29 S eats.........................................................................................2D-29 Body M ounting................................................................... ..2D-34 Applique Procedures......................................................... ..2D-34 Adhesive Body Side M oldings........................................ ..2D-34 FRONT END WINDSHIELD WIPERS Windshield wiper units on all models are of the twospeed electric type. A single wiper motor unit, mounted to the left side of the dash panel inside the engine com part­ ment, powers both wiper arms. The wiper arm operating link rods and pivot mountings on these models are located in the outside air inlet plenum chamber. Arm Adjustment To adjust sweep of blades, turn on wipers and note sweep of arms. If necessary, remove one or both arms as follows: Pull outer end of arm away from glass which will trip lock spring at base of arm and release spring from undercut of pivot shaft. While holding arm in this position, pull outward on cap section at base of arm to remove arm. Arm can be reinstalled in any one of several positions due to serrations on pivot shaft and in arm cap. See figure 2D-7. 4. Remove two screws from each transmission pivot shaft assembly to windshield frame. Remove wiper linkage and transmission from plenum. Installation 1. Place wiper linkage and transmission into position. Secure assembly with two screws at each transmission. 2. Attach end of cross rod to drive arm of motor assembly. Secure rod. 3. Before installing wiper arms or cowl ventilator grille, operate wiper motor momentarily which should rotate pivot shafts to park position. 4 .? Install arms, grille and shafts. Wiper Arm Pivot Shafts and Linkage Removal 1. Remove windshield wiper arm s from pivot shafts. Procedure for removing arms is explained previously under ‘A rm A d ju ste m n t". 2. Remove cowl ventilator grille. 3. Remove two nut and lock washer assemblies from the connector link to motor drive arm via the plenum access hole. L IG H T T R U C K SE RV IC E M A N U A L Fig. 2D-7--Windshield Wipers BODY 2D-5 INSTRUMENT PANEL COMPARTMENT AND LOCK Replacement Removal of the entire assembly including door may be accomplished by removing four screws which attach hinge just below box. See figure 2D-8. The outer door panel may be removed, leaving the compartment intact, by removal of four screws. Access to the door stop bumper is gained by reaching into c o m partm ent opening with door partially open. Adjustment Engagement of lock in striker may be adjusted by loosening striker retaining screws and moving the striker to desired position. INSIDE REAR VIEW MIRROR - FIGURE 2D -11 Replacement OUTSIDE REAR VIEW MIRRORS R ear view mirror installations are shown in figure 2D9, 2D-10 and 2D-11. Occasional tightening of mounting and assembly bolts and screws will sharply decrease occurrence of failure due to door slamming or road shock. C a m p e r m irror installation is similar to the below eyeline mirror installation. 1. Remove screw retaining mirror to its glass-mounted bracket and remove mirror. 2. Install mirror into its mounting bracket. Torque screw to specifications. COWL VENT VALVE - FIGURE 2D-12 i Two styles are shown in Figure 2D-12. Removing the attaching screws allows removal of the valve from the side panels. Fig. 2D-9--Rear View Mirror - Base L IG H T T R U C K SERVICE M A N U A L 2D-6 BODY BODY GLASS CAUTION:A!ways wear gloves and eye glasses when handling glass to avoid personal injury. CK TRUCK WINDSHIELD REPLACEMENT The windshield is a one-piece type and is retained in the windshield opening by a urethane bonded rubber weather­ strip. See figure 2D-13. To replace a window installed with urethane adhesive requires replacement of the adhesive material. Adhesive service kits No. 1052420 and No. 9631000 contain some of the materials needed to remove and replace a urethane adhesive installed glass. These kits and other materials that may be required can be obtained through the service parts system. The components of glass adhesive kits (urethane) No. 1052420 and 9631000 are as follows: 1. One tube of urethane adhesive material. 2. One dispensing nozzle. W hen replacing a cracked windshield glass, it is very important that the cause of the glass breakage be deter­ mined and the condition corrected before a new glass is installed. Otherwise, it is highly possible th a t a small obstruction or high spot somewhere around the windshield opening will continue to crack or break the newly installed windshield especially when the strain on the glass caused by this obstruction is increased by such conditions as wind pressures, extremes of temperature, motion of the vehicle, etc. LIG H T T R U C K SE RV IC E M A N U A L 3. Steel music wire. 4. Rubber cleaner. 5. Rubber primer. 6. Pinch-weld primer. 7. Blackout primer. 8. Filler strip (for use on windshield installations on vehicles equipped with embedded windshield antenna). 9. Primer applicators. BODY 2D-7 Additional Material Required: 1. Rubber lubricant No. 1051717 (available through the service parts system). 2. Alcohol for cleaning edge of glass. 3. Adhesive dispensing gun No. J-24811 or a standard household cartridge type gun reworked as follows: a. Widen end slot to accept dispensing end of adhesive material tube. b. Reduce diameter of plunger disc on rod so that disc can enter large end of adhesive material tube. 4. Commercial type razor knife (for cutting around edge of glass). 5. Weatherstrip tool set J - 2 189. 6. Six glass spacers J-22577 (for checking windshield glass to opening). Removal Checking Windshield Opening 1. Before removing the windshield, mark the location of the break on the windshield rubber channel and the body. Protect the paint finish inside of the cab. Mask around the windshield opening and outside, lay a suitable covering across the hood and fenders. 2. Remove windshield reveal molding (lock strip) and reveal molding cap. Due to the expanse and contour of the windshield it is imperative in the event of a stress crack that the windshield opening be thoroughly checked before installing a replace­ ment windshield. The replacement glass is used as a template. 1. Check for the following conditions at the previously marked point of fracture. a. Chipped edges on glass. 3. To free windshield ru bb er channel of w eatherstrip loosen the lip of the windshield weatherstrip from the pinchweld flange along the top and at the sides by applying firm, controlled pressure to the edge of the glass. At the same time assist the lip of the rubber weatherstrip channel over the pinchweld flange with a flat bladed tool. See figures 2D-14 and 2D-15. 4. With the aid of an assistant outside the cab, remove the windshield from the opening. See figure 2D-16. 5. Remove all excess urethane adhesive and any remain­ ing pieces of weatherstrip from pinch-weld flange. 6. If sheet metal and paint repairs are required, refer to "Repairing and Refinishing Pinchweld Flange" of this section. Fig. 2D-14--Applying Pressure to Windshield b. Irregularities in body opening. c. Irregularities in rubber channel weatherstrip. 2. Check flange area for solder, weld high spots, or hardened spot-weld sealer. Remove all high spots. 3. Check windshield glass to opening, by supporting glass with six spacers contained in packet J-22577. See figure 2D-17. NOTICE: Do not strike glass against body metal. Chipped edges on the glass can lead to future breaks. 4. W ith the windshield supported and centered in its opening, check the relationship of the glass to the body opening flange around the entire perimeter of the glass. Fig. 2D-16--Removing Windshield from Opening LIG H T T R U C K SERVICE M A N U A L 2D-8 BODY maximum), then wipe both channels with a clean dry cloth. 4. Apply rubber primer to both channels of rubber weatherstrip that were cleaned in the previous step and are shown in View A. Allow primer to cure for at least 30 minutes (30 day maximum). 5. Thoroughly clean surface of glass to which blackout primer will be applied (around edge of inside surface) by wiping with a clean, alcohol dampened cloth. Allow to air dry. NOTICE: When cleaning windshield glass, avoid con­ Fig. 2D-17--CHecking Windshield Opening 5. Check the relationship of glass to opening as follows: a. Inside edge of glass to body flange. b. Outer edge of glass to parallel body metal. 6. Mark areas of body metal or flange to be reformed. Remove glass and correct as outlined in this section. 7. Recheck windshield in its opening and if satisfactory proceed as follows: Repairing and Refinishing Pinch-Weld Flange and/or Surrounding Areas 1. Repair all metal deformations in the windshield open­ ing area for appearance. 2. Sand to smooth surface using No. 320 sandpaper. 3. Apply prim er - surfacer (D uPon t 80 S Primer Surfacer, PPG 204-1000 Red Flash Primer or PPG 700-345 - R epair P rim e r/o r equivalent) and sand smooth for required surface. 6. 7. 8. 9. 10. 11. 12. 13. 4. Apply color coats of 9984024 acrylic enamel (or equivalent) catalyzed as indicated. Installation (Fig. 2D-18) Installation of the windshield requires a number of timed (cure time) steps. This timing is important and must be followed. All cure times are minimum, unless indicated otherwise. W hen performing a step that requires a cure time, it is not necessary to stop and wait for the cure time to elapse. Make a note of the cure time and move on to any following step th a t does not interfere with the timed sequence. 1. Wipe pinch-weld clean with a dry cloth. Make sure most of the previous urethane has been removed. 2. Apply pinch-weld primer with a new applicator to pinch-weld as shown in View B. Primer must be thoroughly stirred and agitated prior to application. Allow primer to cure for at least 30 minutes (100 hour maximum). Pinch weld flange must not exceed 160°F (38°C) at time of primer application. 3. Apply rubber cleaner with a new applicator to both channels of rubber weatherstrip as shown in View A. Allow cleaner to remain for at least 5 minutes (4 hour L IG H T T R U C K SERVICE M A N U A L 14. 15. 16. 17. 18. 19. tacting edge of plastic laminate material (on edge of glass) with volatile cleaner. Contact may cause discol­ oration and deterioration of plastic laminate by wicking action. DO N O T use a petroleum base solvent such as kerosene or gasoline. The presence of oil will prevent adhesion of new material. Apply blackout primer to the same area of the wind­ shield glass that was cleaned in the previous step and is shown in View C. Allow to dry to touch. Apply a 3/16 inch minimum diameter bead of urethane adhesive around pinch-weld flange as shown in View B. Windshield glass must be installed within 20 minutes after performing this step. Apply a mist of plain water to the urethane bead on the pinch-weld flange, wetting it fully. Install rubber weatherstrip to the pinch-weld flange. Apply a 3/16 inch minimum diameter bead of urethane adhesive to rubber weatherstrip glass channel as shown in View D. Apply a mist of lubricant to surface " C " or weather­ strip as shown in View D, wetting it fully. Install windshield within 5 minutes after performing this step. On windshields equipped with embedded antenna, tape pigtail of antenna to inside surface of windshield glass in a convenient and accessible position. With the aid of a helper, lift glass into window opening. Suction cups may be used but are not mandatory. Then, install glass in channel of weatherstrip. Apply lubricant to lockstrip channel. Windshield must be seated prior to application of lubricant. Use J - 2 189 weatherstrip tool set and install lockstrip in channel of weatherstrip. Install lockstrip cap at lock­ strip joint. Install windshield wiper arms and blades. On windshields equipped with embedded antenna, connect antenna pigtail to radio antenna lead. Install inside trim panels. Install rear view mirror to windshield. STATIONARY BODY GLASS Replacement The method used to remove the windshield glass may be applied to other stationary glass, such as shown in figures 2D-20 and 2D-21. Remember to check for cause of break­ age, and to always wear gloves when handling glass. Installation procedure is similar to "Windshield Replace­ ment" found earlier in this section with exception of steps relating to urethane adhesive. BODY 2D-9 Fig. 2D-18--Windshield Installation-CK Truck LIG H T T R U C K SE RV IC E M AN U AL 2D-10 BODY Fig. 2D-19—Installing Reveal Molding Fig. 2D-20--Back W indow Glass BODY SIDE DOORS DOOR ADJUSTMENTS Doors can be adjusted for alignment of clearance in the cab door opening, and for proper latching. Door alignment adjustments are made at the striker bolt, and at door hinges. The door, when properly located in door opening, will have LIG H T T R U C K SERVIC E M A N U A L .19 inch clearance at the top and side edges, and .25 inch clearance at the bottom. The door should be adjusted in the opening so the edge of the door across the top and also at the lock side is parallel with the body opening as nearly as possible. BODY 2D-11 Hinge Adjustment Door hinge bolt holes are oversized to make adjustment possible. Alignment adjustments can be made by loosening the proper hinge bolts, aligning door to proper position, and tightening bolts securely (fig. 2D-22). Striker Bolt Adjustment W ith the use of J-23457, shown in figure 2D-23, the striker bolt can be adjusted in any of three ways. See figure 2D-24. 1. Up and down - To adjust striker up or down, loosen bolt, adjust to desired height, and tighten bolt securely. This adjustment is important to assure that the right proportion of door’s weight will rest on striker bolt when door is closed. If bolt is positioned too high on pillar, rapid wear will occur to the lock cam; if too low, an extra load will be placed on door hinges as well as pull door downward and out of alignment. 2. In and Out - To adjust striker in and out, loosen bolt, adjust horizontally to desired position and tighten bolt securely. 3. Forward and R earw ard-T o m ake this a d justm ent, loosen striker bolt, shim to desired position, and tighten bolt securely. Fig. 2D-23--Loosening Striker Bolt 2. With special Tool J-22585 remove 3 bolts securing front door upper hinge to cowl pillar. a. Remove the door to upper hinge retaining bolts. b. With aid of an assistant to support weight of door, remove the door to lower hinge retaining bolts and remove door. Installation FRONT DOOR ASSEMBLY Replacement Remove the door assembly from the body by removing the hinge-to-door attaching bolts. 1. Install hinge snugly on pillar in same location as hinge removed. 2. With the aid of an assistant fasten the door to the hinge. 3. Adjustment of the door lock and striker plate should be made after the door is positioned in the opening. DOOR HINGE DOOR TRIM PANELS - CK MODELS The door check is part of the front door upper hinge. The front door torque rod check holds the door in either of two positions between full open and closed. The front door check-hinge assembly is replaced as a complete unit as follows. See figure 2D-22. Removal Removal 1. Loosen front fender rear bolts. 1. Using tool J-9886-01, remove clip retaining window crank (fig. 2D-26). 2. Remove door lock knob. 3. Remove (4) screws securing lower edge of trim panel. 4. Remove (2) arm rest attaching screws and remove arm rest pad. Fig. 2D-24--Typical Striker Bolt Adjustment L IG H T T R U C K SERVICE M A N U A L 2D-12 BODY 5. Remove (1) screw at door handle cover plate and (1) screw located under arm rest pad. 6. If equipped assist strap, remove (2) screws retaining assist strap. 7. Remove trim panel by carefully prying out at trim retainers located around perimeter of panel. Installation Before installing door trim assembly, check that all trim retainers are securely installed to the assembly and are not damaged. 1. To install door trim assembly, pull door inside handle inward; then position trim assembly to inner panel, inserting door handle through handle hole in panel. 2. Position trim assembly to door inner panel so trim retainers are aligned with attaching holes in panel and tap retainers into holes with a clean rubber mallet. 3. Install previously removed items. DOOR VENTILATOR ASSEMBLY-Fig. 2D-28 Removal The channel between the door window glass and door vent is removed as part of the vent assembly. 1. R egulate the door window glass to the full down position. 2. Remove clip from the window regulator handle, and knob from lock rod. R E T A I N I N G SPR IN G (D IS E N G A G E D ) \ ^ ^ IIN S ID E H A N D L E V ^ - r PUSH T O O L IN D m E C T I O N OF ARROW -M Jj^ T O O L J-9886-01 Fig. 2D-26--Clip Retained Inside Handle Removal LIG H T T R U C K SE RV IC E M A N U A L 3. Remove arm rest screws and trim panel. See figure 2D27. 4. Remove screws attaching ventilator lower assembly to door panel. 5. Remove three screws at the upper front of the door frame. 6. Pull upper portion of vent assembly rearward and raise upward while rotating counter clockwise. 7. T urn vent assembly 90° and carefully remove by guiding up and out. See figure 2D-29. Ventilator Glass Replacement 1. Using an oil can or similar means, squirt prepsol or equivalent on the glass filler all around the glass channel or frame to soften the old seal. When the seal has softened, remove the glass from the channel. 2. Thoroughly clean the inside of the glass channel with sandpaper, removing all rust, etc. 3. Using new glass channel filler, cut the piece to be installed two inches longer than necessary for the channel. Place this piece of filler (soapstoned side of filler away from glass) evenly over the edge of the glass BODY 2D-13 BEND TAB OVER HEX NUT Fig. 2D-31--Bend Tabs Over Hex Nut Fig. 2D-29--Removing Ventilator Assembly which will fit in the channel. The extra filler extending beyond the rear edge of the glass should be pinched together to hold it in place during glass installation. One side of this filler (the outside of the roll) is soapstoned. This is the side which goes into the metal channel. 4. Brush the inside of the metal glass channel freely with ordinary engine oil. This will enable the glass and filler to slide freely into the channel. Push the glass with the filler around it into the channel until it is firmly seated. After the glass is firmly in place, the oil softens the filler, causing it to swell, thereby making a watertight seal. Trim off the excess filler material around the channel and at the ends of the channel. Glass should be installed so that rear edge is parallel to the division post. Allow full cure before water testing. Installation 1. Lower the ventilator assembly into the door frame. 2. M ake certain the rubber lip is positioned inside the inner and outer panel before tightening screws. 3. Reinstall all screws and tighten. 4. Install and tighten the three screws at the upper front of the door. Adjustment 1. Adjust the ventilator by placing wrench on adjusting nut thru access hole and turning vent window to the desired tension. See figure 2D-30. 2. After making adjustment bend tabs over the hex nut on base of assembly. See figure 2 D -3 1. 3. Install arm rest screws and trim panel. 4. Install window regulator handle. DOOR WINDOW ASSEMBLY-FIG. 2D-32 Replacement 1. Completely lower glass to bottom of door. 2. Remove door arm rest and trim pad as outlined in this section. 3. Mask or cover upper portion of door window frame. Remove ventilator assembly as previously outlined. 4. Slide glass forward until front roller is in line with notch in sash channel. Disengage roller from channel. 5. Push window forward and tilt front portion of window up until rear roller is disengaged. See figure 2D-33. 6. Put window assembly in normal position (level) and raise straight up and out. 7. Reverse above procedure for installation. WINDOW REGULATOR-MANUAL--FIG. 2D-32 Replacement 1. Raise window and tape glass in full up position using cloth body tape. 2. Remove trim panel as outlined previously. 3. Remove screws attaching regulator to door inner panel. 4. Remove regulator by sliding regulator rearward, disen­ gaging rollers from sash channel. A notch is provided in the sash channel to allow disengagement of the forward roller on the window regulator (Fig. 2D-32). Fig. 2D-30--Adjusting Tension 5. Install regulator by reversing above steps. Lubricate regulator gear with lubriplate or equivalent. LIG H T T R U C K SERVIC E M AN U AL 2D-14 BODY NO TCH SASH CHANNEL; Fig. 2D-32--Door W indow and Regulator WINDOW REGULATOR - POWER - CK MODELS In the case th a t window will not operate, check electrical connections first. Figure 2D-34 illustrates location of junctions, switch, relay and circuit breaker. Replacement CAUTION:Electrical connectors must be removed from window lift motor before performing any operation on the regulator, or personal injury could occur. Figure 2D-35 illustrates location of regulator on door and wiring. 1. Raise glass to full up position and tape to door frame using cloth body tape. 2. Disconnect battery ground cable. 3. Remove door trim panel as previously outlined. Fig. 2D-34--Power W indow Switch, Relay and Breaker Assembly A notch is provided in the sash channel to allow disengagement of the forward roller on the window regulator (fig. 2D-32). 8. Remove regulator assembly through access hole in door. CAUTION:Step 9 must be performed when reg­ ulator is removed from door. The regulator lift arms are under tension from the counterbalance spring and can cause serious injury if the motor is removed without locking the sector gear in position. 9. Drill a hole through the regulator sector gear and back plate. DO N O T drill hole closer than 1/2" (12.7mm) to edge of sector gear or back plate. Install a pan head 4. Remove remote control bolts and lay control assembly aside for access. 5. Remove regulator to door panel attaching screws. 6. Disconnect harness from regulator. 7. Slide regulator assembly rearward, disengaging rollers from sash channel. N O TC H ROLLER Fig. 2D-33--Removing Door Glass L IG H T T R U C K SERVICE M A N U A L Connector BODY 10. 11. 12. 13. 14. 15. 16. sheet metal tapping screw (No. 10 - 12 x 3/4) in drilled hole to lock sector gear in position. Remove motor to regulator attaching screws. Remove motor from regulator. Prior to installation, lubricate the motor drive gear and regulator sector teeth. The lubrication used must be cold weather approved to a minimum of minus 20° Fahrenheit (-29°C). Install regulator motor to regulator. Make sure the motor pinion gear teeth mesh properly with the sector gear teeth before installing the three motor attaching screws. Remove screw locking sector gear in a fixed position. Insert regulator into door in such a position that motor connector can be installed onto motor. Reinstall regulator into door. LOCKS, HANDLES AND RODS Door Lock Assembly—Fig. 2D-36 Replacement 1. 2. 3. 4. 5. Raise window to full up position. Remove trim panel as outlined in this section. Remove clip from inside handle rod-to-lock. Remove clip from outside handle rod-to-lock. Remove screws which attach lock assembly to door panel. 6. Remove lock and remote control rod as an assembly. 7. To install lock assembly, reverse above steps. Be sure to replace all clips removed earlier. 2D-15 Door Outside Handle—Fig. 2D-37 Replacement 1. 2. 3. 4. Raise window to full up position. Remove trim panel as outlined. Remove clip from outside handle rod-to-lock. Remove screws which retain outside handle to door panel. 5. Remove handle and control rod. 6. Reverse above procedures to install outside handle. Door Lock Cylinder -Fig 2D-37 Replacement 1. Raise door window. 2. Remove trim panel as outlined. 3. Use a screwdriver or other suitable tool to slide the lock cylinder retaining clip out of engagement with the lock cylinder. 4. Remove lock cylinder. 5. To install, reverse the above steps. Door Inside Handle Replacement 1. Remove trim panel as outlined. 2. Disconnect control rod from inside handle, as shown in figure 2D-38. 3. Remove screws retaining inside handle to door. 4. Remove inside handle. 5. Reverse above steps to install. POWER DOOR LOCKS - CK MODELS (Fig. 2D-39) Replacement 1. Disconnect battery ground cable. 2. Remove door trim panel to gain access to power door lock motor. 3. Disconnect electrical connector from motor. LOCK' Fig. 2D-36--Door Lock Assembly and Rods Fig. 2D-37--Outside Handle and Lock Cylinder LIG H T T R U C K SERVIC E M A N U A L 2D-16 BODY 4. Remove screws attaching motor to door inner panel. 5. Remove door lock lever from rubber mount at top of motor actuator and remove motor through access hole. 6. To install, reverse steps 1 through 5 above. DOOR TO BODY OPENING WEATHERSTRIP-FIG. 2D-40, 2D-41 Side door sealing incorporates an inner seal Fig. 2D-40 and a secondary seal Fig. 2D-41. The inner seal is mounted on the body opening welding flange and goes completely around the periphery of the opening. The secondary seal is adhered to the upper portion of the door by adhesive and a screw at either end of the seal. The molded weatherstrip m aterial of the inner seal is snapped in place. A fter removing all foreign material from door opening surface proceed as follows: 3. Remove side door inner weatherstrip seal. 4. Starting at the bottom center of the door opening, install seal on welded flange. 5. Trim inner weatherstrip with a notch and butt ends together. 6. Reinstall sill plate and sill plate retaining screws. REAR SIDE DOOR-CREW CAB AND SUBURBAN MODELS Adjustments and Hinge Replacement The procedures for hinge replacement, and for hinge and striker bolt adjustment are similar to those detailed in the front door adjustment procedure. Access to the hinges of the rear door is shown in figure 2D-42. 1. Open door and block open. STATIONARY GLASS-REAR DOOR 2. Remove sill plate retaining screws and remove sill plate. Replacement LIG H T T R U C K SERVIC E M A N U A L 1. Lower window to full down position. 2. Remove remote control knob and window regulator handle. BODY 2D-17 WINDOW GLASS-FIG. 2D-46 3. Remove screws retaining door trim pad, and remove trim pad. See figure 2D-43. 4. Remove glass run channel by removing screws retain­ ing channel to door. See figure 2D-44. 5. Remove stationary glass. 6. Replace glass by reversing above procedure. Glas Run Channel Adjustment Figure 2D-45 illustrates the front run channel. At the lower end, a slotted bracket provides for in-and-out adjust­ ment. The screw and locknut at that bracket allow fore-andaft adjustment. Together, this allows proper alignment of the glass to the rear glass run channel for full up and down travel. Replacement 1. Lower glass to full down position. 2. Remove remote control push botton knob, window regulator handle and trim pad. 3. Remove stationary glass as previously outlined. Re­ move screws from rear division channel, and slide channel rearward in the opening. 4. Raise glass as far as possible, then slide glass until the roller is in line with the notch in the sash channel. See figure 2D-46. Disengage roller from channel. 5. Tilt window outboard and move until other roller can be removed from channel. 6. Raise window up and out. 7- Reverse above procedure for installation. LIG H T TR U C K SERVICE M A N U A L 2D-18 BODY WINDOW REGULATOR ASSEMBLY-FIG. 2D-46 Remote Control—Fig. 2D-48 Replacement Replacement 1. Remove trim pad, stationary glass, and window glass as outlined earlier. 2. Remove screws attaching regulator assembly to door inner panel. 3. Remove regulator assembly through opening in door. 4. Install regulator by reversing above procedure. Lubri­ cate regulator gear with lubriplate or equivalent. 1. Remove regulator handle, remote control knob and trim pad. 2. Disconnect remote control lower rod from door lock assembly. 3. Remove two screws securing each remote control lever to door panel. 4. Remove remote control levers and rods through door opening. 5. Replace by reversing above procedure. LOCKS HANDLES AND RODS Lock Assembly—Fig. 2D-47 Replacement 1. Remove window regulator handle, remote control push button knob and trim pad as outlined previously. 2. Disengage three clips which retain control rods to lock assembly. a. Inside handle control rod. b. Remote control lower rod. Outside Handle-Fig. 2D-49 Replacement 1. Remove regulator handle, remote control rod and trim pad as outlined previously. 2. Disengage outside handle control rod from lock assem­ bly by removing clip, as shown in figure 2D-49. 3. Remove two screws securing outside handle to door panel. 4. Remove handle assembly. c. Outside handle control rod. 3. Remove screws retaining lock assembly to door panel, then remove lock assembly. 4. Install lock by reversing above procedure. Be sure to replace all clips removed with new clips on installation. Inside Handle—Fig. 2D-47 Replacement 1. Remove regulator handle, remote control knob and trim pad as outlined previously. 2. Disconnect control rod from inside handle by removing clip as shown in figure 2D-47. 3. Remove inside handle by removing four screws which secure handle to door panel. 4. Replace handle by reversing above procedure. L IG H T T R U C K SERVIC E M A N U A L Fig. 2D-48--Remote Control Assembly BODY 5. Replace by reversing above procedure. WEATHERSTRIP-FIG. 2D-50 The procedure outlined in Front Door Weatherstrip may be applied to the Rear Side Door Weatherstrip, shown in figure 2D-50 with the following exception: a. Begin installation by positioning the weatherstrip "internal core" (approximately 6" long) center in the upper front corner of the door opening. b. Proceed as outlined previously. REAR DOORS SUBURBAN MODEL ONLY Adjustments Rear doors may be adjusted in the body opening by loosening hinge bolts and repositioning door, then retighten­ ing bolts. See figure 2D-54 for hinge bolt location. Rear door wedges and strikers should be adjusted as shown in figure 2D-55. Be sure that adjustments are as shown to insure proper latching of the rear doors. 2D-19 LOCKS, HANDLES AND RODS The rear door lock, outside handle, lock cylinder, control rods and latch are shown in figures 2D-51 and 2D52. The rods can be disconnected from the lock, latch or handle by disengaging the retaining clips, as shown. The lock cylinder is removed in the same manner as the front side door lock cylinder. REAR DOOR CHECK STRAP Figure 2D-53 shows the cloth check strap used for rear doors. The door may be completely opened by removing the strap pin from the bracket. The bracket attaches to the pillar with three screws; the strap is fastened to the door panel with two screws and an attaching bar. WEATHERSTRIP Weatherstrip installation is shown in Figs. 2D-55 and 2D-56. Proper installation is dependent on completely cleaning all foreign material from old installation and using a quality cement on the new installation. LIG H T T R U C K SERVICE M A N U A L 2D-20 BODY Fig. 2D-52--Rear Door Outside Handle and Lock Cylinder Fig. 2D-53--Rear Door Check Strap LIG H T T R U C K SE RV IC E M A N U A L BODY 2D-21 Fig. 2D-54--Wedge and Striker Adjustments -(Suburban) ENDGATES SUBURBAN AND UTILITY MODELS Suburban and utility models use endgates of similar, yet distinct design. Separate procedures follow for service on each of these endgates. 5. Lift endgate to almost closed position and remove support cables. 6. Remove endgate with torque rod. 7. To install, reverse removal procedure. ENDGATE ASSEMBLY - SUBURBAN MODELS ONLY HINGES Replacement Replacement 1. Lower endgate, and removed hinge access covers. See figure 2D-57. 2. Remove endgate-to-hinge bolts. 3. Remove L.H. torque rod bracket, shown in figure 2D58. 4. If equipped with electric powered window, disconnect wiring harness. If necessary to remove hinges, remove en dg ate as outlined previously, and proceed as follows: 1. Remove bolts from each of the hinge assemblies on the underside of the body. See figure 2D-57. 2. Remove hinge assemblies. If the hinge pins are to be removed, note the position of bushings so they may be reinstalled in the same position. 3. Reverse procedure to install. L IG H T T R U C K SE RV IC E M A N U A L 2D-22 BODY CAUTION:Step 10 must be performed if the window is removed or disengaged from the regulator lift arms. The lift arms are under tension from the counter-balance spring, and can cause injury if the motor is removed without locking the sector gears in position. Fig. 2D-58--Torque Rod(Suburban) ENDGATE DISASSEMBLY 1. Remove access cover shown in figure 2D-59, to gain access to interior components. 2. Detach remote control rods from lock assembly by removing clips. 3. Remove bolts securing lock assembly, and remove lock assembly. 4. Remove handle assembly bolts and remove inside handle. 5. Remove R.H. torque rod bracket screws, figure 2D-58, then remove torque rod from endgate. 6. Remove screws connecting cam assemblies to sash assembly, figure 2D-60, then remove cam assemblies. 7. Remove glass from endgate. 8. Unclip and remove inner and outer seal assemblies. 9. Remove screws connecting window regulator assembly to endgate, figure 2D-60, and remove regulator. 10. For endgates with electric window, secure the window regulator lift arms before removing the electric motor, when the window glass has been removed or disengaged from the lift arms. a. Drill a 1/8 (3.1mm) inch hole through the sector gear and back plate, as shown in figure 2D-60. Install a sheet metal tapping screw into the hole to lock the sector gears in position. b. Remove the regulator motor attaching screws and remove the motor assembly. 11. From inside the endgate, remove the nuts fastening the outside handle to endgate and remove the outside handle. See figure 2 D -6 1. If equipped with power tailgate window, detach wiring harness from motor. 12. Remove side bolts connecting left and right glass channels to endgate and remove channels. 13. Removed side latch bolts and remove side latches with control rods. See figure 2D-59. Detach wiring harness from R.H. latch if so equipped. 14. Separate side latch from control rod by pulling control rod thru nylon guide. 15. Reverse the above procedure for reassembly and installation. Adjustments Loosen bolts, adjust at either endgate hinge position or endgate latch, then retighten bolts. ENDGATE ASSEMBLY-UTILITY MODELS ONLY Replacement ACCESS COVER LEVER ASSEMBLY SEAL ^ ^ IN S U L A T O R - HANDLE ASSEMBLY ^ LATCH \ A * ^ASSEMBLY a L / CONTROL ASSEMBLY NYLON GUIDEi REMOTE CONTROL 1. Lower endgate, then remove four bolts securing hinge to body on each side. See figure 2D-62. Disconnect wiring harness, if so equipped. 2.?Disconnect torque rod anchor plate on each side. It is necessary to remove lower bolt only, then let plate swing down. See figure 2D-66. 3. With an assistant, raise endgate part way, then discon­ nect support cables from endgate. See figure 2D-62. 4. Remove endgate by pulling disconnected hinge from body, figure 2D-63, then grasping torque rod with one hand and pulling torque rod over gravel deflector, as shown in figure 2D-64. 5. Individual components may be removed from the endgate now, or after reinstallation. Fig. 2D-59--Latch and Remote Controls(Suburban) LIG H T T R U C K SERVICE M A N U A L 6. To install endgate, reverse the above procedure. BODY 2D-23 Fig. 2D-63--Pulling Hinge Away From Body (Utility) HINGE Replacement 1. Lower endgate and disconnect hinge to be replaced by removing hinge-to-body bolts. See figure 2D-62. 2. At the other hinge, loosen the hinge-to-body bolts. 3. On the hinge to be replaced, remove the hinge-toendgate bolts. 4. Pull the endgate away from the body several inches and withdraw hinge from body. Then lift endgate slightly to allow removal of hinge from endgate. See figure 2D-63. 5. To install hinge, reverse the above procedure. Be sure to install hinge into endgate first, then into the body. Fig. 2D-64--Grasping Torque Rod (Utility) LIG H T T R U C K SERVICE M AN U AL 2D-24 BODY Fig. 2D-65--Removing Access Cover (Utility) TORQUE ROD Fig. 2D-67--Removing Torque Rod (Utility) 2. Disconnect side latch remote control rods from center control by removing retaining clips. See figure 2D-68. Replacement 1. L o w e r e n d g a te a n d re m o v e a cc e ss cover, a s sh o w n in figure 2D-65. 2. Disconnect torque rod anchor plate. It is necessary to remove the lower bolt only, then let plate swing down. See figure 2D-66. 3. Loosen four bolts retaining endgate hinge to body. 4. Move endgate slightly away from body. 5. Remove torque rod retaining bracket on lower edge of endgate. See figure 2D-66. 6. Remove torque rod retaining clip on side edge of endgate. 7. Lift torque rod up and slide from endgate as shown in figure 2D-67. 8. Reverse the procedure above for installation. ENDGATE DISASSEMBLY-UTILITY MODELS ONLY Manual Window 1. Lower endgate and remove acess cover. 3. Remove four screws from each side latch, and with­ draw latch and control rod from endgate, as sown in figure 2D-69. 4. Disconnect control rod from latch. 5. Refer to figure 2D-70 for installation of latch control and blockout rod. 6. Disconnect blockout rod from control assembly by detaching spring and removing two screws retaining rod to inner panel. 7. Disconnect inside handle control rod from control assembly, then remove screws which secure inside handle to inner panel. 8. Remove three screws which retain remote control assembly to inner panel. 9. Remove control assembly and inside handle as shown in figure 2D-71. 10. Refer to figure 2D-72 for window and regulator installation. 11. Roll window to up position. 12. Disconnect sash from regulator as shown in figure 2D73. BRACKET SILENCER TORQUE ROD FRAME Fig. 2D-66--Torque Rod (Utility) LIG H T T R U C K SE RV IC E M A N U A L Fig. 2D-68--Latches and Rods BODY Fig. 2D-69--Removing Side Latch 2D-25 Fig. 2D-71 -Removing Control Assembly ancHnside Handle BLOCKOUT ROD INSIDE HANDLE BRACKET CONTROL ROD CONTROL ASSEMBLY Fig. 2D-70--Control Assembly and Blockout Rod 13. Remove glass from endgate. Fig. 2D-72--Window and Regulator 14. Remove four regulator attaching screws and withdraw regulator from endgate as shown in figure 2D-74. 15. Remove outside handle by removing nuts from inside of outer panel. See figure 2D-61. 16. Reverse the above steps for reassembly. ELECTRIC WINDOW-UTILITY MODELS The window is controlled by a jackscrew mounted to the regulator, drive cable and a 12V DC reversible motor mounted to the endgate inner panel. This circuit also includes a block out switch to prevent operation of the window while the endgate is open (fig. 2D-75). Service procedures for endgate disassembly are the same as outlined above with the following exceptions: Drive Cable The drive cable can be replaced by disengaging the cable from the motor and jackscrew assembly and removing the cable. Reverse removal procedure to reinstall cable. Fig. 2D-73--Disconnecting Sash from Regulator LIG H T T R U C K SERVICE M AN U AL 2D-26 BODY Fig. 2D-74--Removing Regulator Motor (Fig. 2D-76) Removal 1. D is c o n n e c t d riv e c a b le fr o m m o tor. 2. Disconnect wiring harness from motor. 3. Remove (3) motor attaching screws and remove motor. 4. To install, reverse removal procedure. Fig. 2D-75--Power W indow M otor and Switches (Utility) Blockout Switch (Fig. 2D-75) Removal 1. Disconnect L.H. side latch remote control rod from center control by removing retaining clip. 2. Remove side latch retaining screws and disconnect blockout switch wiring. 3. Remove side latch assembly and remove screws retain­ ing switch to side latch. 4. Reverse removal procedures for installation. CABLE Jackscrew (Fig. 2D-76) Removal For endgates with electric window, secure the window regulator lift arms before removing the jackscrew when the window glass has been removed or disengaged from the lift arms. VIEW REG U LA TO R CAUTION:Step 1 must be performed if the w in­ dow is removed or disengaged from the regulator lift arms. The lift arms are under tension from the counterbalance spring, and can cause injury if the motor is removed without locking the sector gears in position. 1. Drill a 1/8 (3.1mm) inch hole through the sector gear and back plate. Install a sheet metal tapping screw into the hole to lock the sector gears in position. 2. Disconnect drive cable at jackscrew. 3. Remove the regulator jackscrew attaching screws and remove the jackscrew assembly. 4. Reverse removal procedure for installation. L IG H T T R U C K SERVIC E M A N U A L Fig. 2D-76--Endgate Regulator, Drive Cable and Motor BODY 3. 2D-27 Remove endgate. 4. Reverse procedure for installation. Align slot in tru n­ nion to coincide with hole in endgate to permit using a tool to hold trunnion while tightening nut. REMOVABLE TOP-FOLDING TOP-UTILITY MODELS Removal 1. Remove access and disconnect courtesy light. 2. Lower the tailgate window and lower the tailgate. 3. Remove six top-to-roof mounting bolts. 4. Remove ten top-to-side panel mounting bolts (5 on each side). 5. Remove upper spare tire brace by removing brace bolt. The spare tire brace must be reinstalled after top is removed. 6. Remove only the rear attaching screws for the side trim panel (12 for LH panel and 11 for RH panel) so that the rear of panel can be pulled away to gain access for removal of hidden top bolt. If rear roll bar equipment is present, it is necessary to remove all the attaching screws, 20 on LH side and 19 on RH side, and the 1 bolt attaching the shoulder belt retractor located behind the access plate on retractor. Then the trim panel is raised and moved forward approx. 2-1/2 inches so th at access can be gained through the cut out in trim panel to remove hidden top bolt. 7. With assistance, lift the top and move rearward for removal. The top should be removed carefully to prevent flexing of the sides and possible damage. Fig. 2D-77--Tailgate TAILGATES-PICKUP AND UTILITY MODELS Fleetside Handle Replacement (Fig. 2D-77) Mandatory Assembly Sequence (Fig. 2D-78) To prevent possible damage to the top and to ensure proper weatherstrip sealing, the following procedure must be followed: 1. Open tailgate. 1. Remove the upper spare tire brace by removing (2) bolts. 2. Remove screws attaching handle assembly to inner side of tailgate. 2. Remove the necessary side trim panel screws. 3. Remove clips from handle assembly and remove handle. 4. Remove screws from each latch assembly and lift off, with actuating rods. Replacement of Trunnion Assembly 1. Lower tailgate half way. 2. Remove both retaining straps. 3. Lift up tailgate at the right side and pull out at the left side to remove tailgate assembly. 4. Remove two screws from trunnion and remove trunnion. Stepside Endgate Replacement (Fig. 2D-77) 1. Unhook endgate chain assembly at each side. 2. Remove bolt and lock washer from each trunnion in carrier box endgate. 3. Place top on box using the two rear guide pins as locators. 4. Install bolts # 6 on both sides and tighten. 5. Bolting must start with the rear vertical bolt # 1. Now going forward install # 2 LH side only, # 3 and # 4 . The RH side # 2 bolt will be installed later. 6. Loosen bolts # 6 on both sides. 7. Install and tighten bolts # 5 on both sides. 8. Re-tighten bolts # 6 on both sides. 9. Install and tighten remaining bolts to cab. 10. Install and tighten the 2 rear hidden bolts. 11. Install the side trim panel screws that were removed including the shoulder belt retractor bolt if it had to be removed. Finally, reconnect the courtesy light and reinstall the upper spare tire brace using 2 bolts, with one of the bolts being the # 2 R.H. top-to-side panel bolt. L IG H T T R U C K SERVICE M AN U AL 2D-28 BODY ** V f> UNSNAP AND REMOVE COVER BOOT AND STORE IN VEHICLE Fig. 2D-79--Folding Top Assembly L IG H T T R U C K SE RV IC E M A N U A L i BODY 2D-29 SEATS SEAT BELTS SERVICING LAP AND SHOULDER BELTS - ALL MODELS Before servicing or replacing lap and shoulder belts, including single loop belt systems, refer to the following precautionary items: 1. Lap and shoulder belts will be serviced as follows: a. All belts will be serviced in complete sets. b. Do not intermix standard and deluxe belts on front or rear seats. 2. Keep sharp edges and damaging objects away from belts. 3. Avoid bending or damaging any portion of the belt buckle or latch plate. 4. Do not bleach or dye belt or strap webbing (clean with a mild soap solution and water). 5. When installing lap or shoulder belt anchor bolt, start bolt by hand to assure that bolt is threaded straight. 6. Do not attempt repairs on lap or shoulder belt retractor m echanism s or lap belt re tra c to r covers. Replace defective assemblies with new service replacem ent parts. 7. Do not attem pt to remove seat belt retractor cover. The cover and the long rivet securing the cover to the retractor are not available as service replacement parts. Fig. 2D-80--Seat Belt Installation (Chassis Cab) LAP BELTS AND SHOULDER BELTS The shoulder belts and lap belts are attached to the front seat lap belt latch plate and connected to an inertia locking retractor installed to the floor or quarter inner panel above the right and left side of the front seat. The belts remain unlocked to allow occupants to move freely while the vehicle is being operated. W hen the vehicle decelerates or changes direction abruptly, the belts are locked in position by a pendulum that causes a locking bar to engage a cog of the retractor mechanism. Removal and Installation Refer to illustrations on following pages and select the appropriate illustration for removing and installing lap belts and shoulder belts. Internal drive thread-forming anchor bolts are used to secure lap belts to the floor pan. To remove or install internal drive anchor bolts, use door lock striker and lap belt anchor bolt removal tool J-23457 or equivalent. Start bolt by hand to assure that bolt is threaded straight. SEAT MOUNTING Typical Seat Mounting provisions are shown in figures 2D-83 through 2D-89. NOTICE: See N O T I C E on page 1 of this section regarding fasteners used on seats and seat belts. SEAT SEPARATOR COMPARTMENT Figure 2D-90 illustrates assembly and installation of the CK model seat separator compartment. Fig. 2D-81--Seat Belt Installation (Utility) L IG H T TR U C K SERVICE M A N U A L 2D-30 BODY Fig. 2D-82--Seat Belt Installation (Suburban) Passenger and Driver Seat (Suburban) L IG H T T R U C K SERVICE M A N U A L BODY 2D-31 Fig. 2D-85--Passenger's Bucket Seat (Chassis Cab) LIG H T TR U C K SERVICE M A N U A L 2D-32 BODY Fig. 2D-88--Rear Bench Seats (Suburban) LIG H T T R U C K SERVIC E M A N U A L BODY 2D-33 Fig. 2D-89--CK Utility Seat Attachments LIG H T T R U C K SERVICE M A N U A L 2D-34 BODY BODY MOUNTING The removal of anyone bodymount necessitates the loosening of adjacent body mountings to permit the frame to be separated from the body. Care should be exercised to prevent breakage of plastic fan shroud, or damage to frame attachments such as steering column, brake pipes, etc., during replacement of body mounts. During installation of a body mount, caution should be used to insure that the body mount is properly seated in the frame mounting hole, otherwise a direct metal to metal contact will result between the frame and body. The tube spacer should be in all bolt-in body mounts and the insulator or metal washer positioned to prevent contact with the frame side rail. Do not over-torque the body mount or a stripped bolt may result. Do not use lubricants of any kind on the rubber parts of the mounts. Proper clamping by the mount depends on clean and dry surfaces. If the body mount bolt does not screw in smoothly, it maybe necessary to run a tap through the cage nut in the body to remove foreign material. Caution should also be used to insure th at tap doesn’t punch through underbody. The sequence of mounting attachments is shown in figures 2D-91 through 2D-94. APPLIQUE PROCEDURES Refer to Section 2C, Chassis Sheet Metal, for proce­ dures relating to decal and woodgrain appliques. ADHESIVE BODY SIDE MOLDING Refer to Section 2C, Chassis Sheet Metal, for proce­ dures relating to installation of adhesive moldings. Fig. 2D-90--Seat Separator Compartment and Door-CK Models L IG H T T R U C K SE RV IC E M A N U A L BODY 2D-35 C-30 J Fig. 2D-91--Body Mounting (Chassis Cab) Fig. 2D-92--Body Mounting (Crew Cab) LIG H T T R U C K SERVICE M AN U AL 2D-36 BODY Fig. 2D-94--Body Mounting (Utility) LIG H T T R U C K SE RV IC E M A N U A L BODY 2D-37 G MODELS INDEX Front End Windshield W ipers........................................................ 2D-37 Cowl Ventilator Grille................................................... 2D-38 Side Ventilator V alve.................................................... 2D-38 R ear View M i r r o r ......................................................... 2D-38 Body Glass Windshield G lass............................................................ 2D-39 Stationary G la s s ............................................................. 2D-42 Swingout G la ss ............................................................... 2D-42 Front Door A djustm ents..................................................................... 2D-43 R eplacem ent.................. ................................................. 2D-44 W eatherstrip.................................................................... 2D-44 H inges............................................................................... 2D-44 Ventilator.......................................................................... 2D-44 Window and R eg u lato r................................................ 2D-45 Locks, Handles, R od s...................................................... 2D-46 Sliding Side Door Description....................................................................... 2D-48 A djustm ents......................................................................2D-48 Front L atch .................. ................................................. 2D-52 Rear L a tc h ..................................................................... 2D-53 Upper Rear Hinge...................................................... 2D-53 Strikers............................................................................ 2D-55 Rear Door H i n g e ................................................................................ 2D-55 Remote C o n tro l.............................................................. 2D-55 Latches and R o d s.......................................................... 2D-55 Adjustm ents..................................................................... 2D-56 Seats Drivers S e a t ........................................................ ............ 2D-57 Passenger S e a t ................................................................ 2D-58 Rear S e a t s ....................................................................... 2D-60 Roof V e n t .......................................................... ............. 2D-60 2D-($0 Seat Belts...................................................................... Decal Applique P ro c e d u re ............................................... 2D-60 Adhesive Body Side M o ld in gs........................................ 2D-60 FRONT END WINDSHIELD WIPERS Windshield wiper units on all models are of the twospeed electric type. A single wiper motor unit, mounted to dash panel at top and to left of engine cover inside cab, powers both wiper blades. The wiper blade operating link rods and pivot mountings on these models are located in the outside air inlet plenum chamber. Arm Adjustment To adjust sweep of blades turn on wipers, then note sweep of arms. If necessary, remove one or both arms as follows: Pull outer end of arm away from glass which will trip lock spring at base of arm and release spring from undercut of pivot shaft. While holding arm in this position, pull outward on cap section at base of arm to remove arm. Arm can be reinstalled in any one of several positions due to serrations on pivot shaft and in arm cap. See figure 2D-95. 4. Remove screws which attach each arm transmission pivot shaft assembly to cowl. Remove pivot shaft assembly with link rod from plenum chamber. Installation 1. Place pivot shaft assembly with link rod into position at cowl bracket. Secure assembly to bracket with two screws. 2. Attach end of link rod to motor drive and arm. Secure rod with the two attaching nuts. 3. Install outside air cowl ventilator grille to top of cowl. 4. Before installing wiper arms, operate wiper motor momentarily which should rotate pivot shafts to park position. Install arms. WIPER ARM PIVOT SHAFTS AND LINK ROD-FIG. 2D-96 Removal 1. Remove windshield wiper arm s from pivot shafts. Procedure for removing arms is explained previously under "A rm Adjustments." 2. Remove screws which attach outside air cowl ventilator grille to cowl. Carefully remove grille from cowl. 3. At center of cowl, remove two attaching nuts which attach link rod to motor drive. Disengage link rods from pins. Fig. 2D-95--Wiper Pattern LIG H T T R U C K SE RV IC E M AN U AL 2D-38 BODY Fig. 2D-96--Windshield W iper Linkage COWL VENTILATOR GRILLE Fig. 2D-97~Cowl Ventilator Grille REAR VIEW MIRRORS Replacement 1. 2. 3. 4. Remove windshield wiper arms. Remove screws retaining grille, figure 2D-97. Remove grille and seal. Reverse above steps to install grille. Inside R ear V ie w M irro r Replacement The inside mirror may be removed by removing screw retaining mirror to its glass-mounted bracket, and lifting mirror off bracket (fig. 2D-99). SIDE COWL VENTILATOR Replacement 1. Remove screws retaining valve guide to panel, as shown in figure 2D-98. 2. Remove valve assembly by depressing pins at top and bottom of valve. 3. Reverse the above steps for installation. L IG H T T R U C K SE RV IC E M A N U A L Outside Rear View Mirrors Outside rear view mirror installations are shown in figure 2D-100. Occasional tightening of m ounting and assembly bolts and screws will sharply decrease occurence of failure due to door slamming or road shock. BODY 2D-39 Fig. 2D-l(X)--Outside Rear View Mirrors BODY GLASS CAUTION:Always wear gloves and eye glasses when handling glass to avoid personal injury. obstruction is increased by such conditions as wind pressures, extremes of temperature, motion of the vehicle, etc. WINDSHIELD GLASS Removal The windshield glass is retained to the body by ure­ thane adhesive. The windshield reveal moldings are vinyl and are retained by two strips of butyl adhesive on the underside of the molding, attaching to the body on one side and the glass on the other and also by a retention lip in the urethane which retains the glass. The windshield rests upon the support molding which is secured to the pinchweld by a bead of butyl adhesive. There are two methods of windshield installation. The windshield removal procedure is the same for both installa­ tion methods with one exception. If the short method installation is to be used, more care must be used during removal to make certain that an even bead of adhesive material remains on window opening to serve as a base for replacement glass, there should not be any loose pieces of adhesive left in the opening. Cut away a sufficient amount of material to allow for the installation of the reveal moldings. W hen replacing a cracked windshield glass, it is very important that the cause of the glass breakage be deter­ mined and the condition corrected before a new glass is installed. Otherwise, it is possible that a small obstruction or high spot somewhere around the windshield opening will continue to crack or break the newly installed windshield, especially when the strain on the glass caused by this 1. Place protective coverings around the area where the glass is being removed. 2. Remove windshield wiper arms, exterior reveal mold­ ings, interior garnish molding and support molding from the pinchweld. Clean up any remaining adhesive left on the body from the reveal molding. LIG H T T R U C K SERVICE M AN U AL 2D-40 BODY The reveal moldings can be removed from the urethane adhesive by taking one end of the molding and pulling it away from the adhesive. The support molding is removed in the same manner from inside the vehicle , pry up one end of the molding and pull it away from the pinchweld. These molding are to be removed prior to windshield removal. 3. Use a knife as shown in Fig. 2D-101 to cut the adhesive completely around the perimeter of the glass. Knife, J-24402-A or equivalent may be used. With help from an assistant, carefully remove the glass. 4. If original glass is to be reinstalled, place it on a protected bench or holding fixture; remove old material using a razor blade or sharp scraper. Any remaining traces of adhesive m aterial can be removed with denatured alcohol or lacquer thinner dampened cloth. When cleaning windshield glass, avoid contacting edge of plastic laminate material (on edge of glass) with volatile cleaner. Contact may cause discoloration and deterioration of plastic laminate by wicking action. DO N O T use a petroleum base solvent such as kerosene or gasoline. The presence of oil will prevent adhesion of new material. W hen replacing the windshield, u rethane adhesive (part no. 9631000 or Essex SCD 551.2 or equivalent) must be used in order to maintain original installation integrity. The short method as described previously can be used where original adhesive material left on window opening pinchweld flanges after glass removal serves as a base for the new adhesive to the glass. This method would be used in cases of cracked windshields or removal of windows that are still intact. The amount of adhesive left in window opening can be controlled during glass removal. However, in some instances all the material must be removed, to make a metal repair or to perform a paintrefinishing operation. In these cases, an additional cleaning and priming step is required before applying the urethane adhesive. See the instructions at the beginning of "Installation". Adhesive Service Kit or Cartridge Material listed have a short shelf life. Be sure materials are fresh. Urethane adhesive cartridge Essex SDC 551.2 or the equivalent are provided singularly. Adhesive Kit No. 9631000 (urethane adhesive) or equivalent contains some of the items needed to remove and replace a urethane adhesive installed glass. Additional items required: 1. Pinchweld primer for enamel painted surface Essex SCD 435.34 or equivalent. 2. Clear glass primer, Essex SCD 435.18 or equivalent. 3. Black glass primer (included in kit 9631000) or Essex SCD 435.20 or equivalent. 4. Solvent for cleaning edge of glass (preferably alcohol) and adhesive dispensing gun No. J-2 4 8 1 1 or an equiv­ alent standard household cartridge type gun reworked as follows: a. Widen end slot to accept dispensing end of adhesive material tube. b. Reduce diameter of plunger disc on rod so that disc can enter large end of adhesive material tube. 5. Commercial type razor knife. 6. Urethane cutting knife No. J-24402-A or equivalent or two pieces of wood for wire handles. 7. Two rubber support spacers. Installation Steps 1 through 11 are to be used for installing glass onto the original urethane adhesive left behind when the windshield was removed. In those instances where the adhesive was entirely removed, to make a metal repair or to perform a paint refinish operation, it is necessary to follow this extra step, before starting Step 1. • Thoroughly clean the metal area surrounding the windshield opening by wiping with a clean alcoholdampened cloth. Allow to air dry. Then apply primer for enamel painted surface Essex SCD 435.34 or equivalent, to the same area, being careful not to allow any spill over onto exposed paint surfaces as this primer will damage the paint finish. The surface should not exceed 38°C (100°F) at the time of the application. Refer to Fig. 2D-102. Allow the primer to dry for thirty minutes. 1. From inside the vehicle, install the support molding onto the pinchweld flange, the joint is to be located at bottom center of the opening. See Fig. 2D-103. 2. Thoroughly clean the edge of the glass to which the adhesive material will be applied by wiping with a clean alcohol-dampened cloth. Allow to air dry. When replacing the windshield, urethane adhesive Part No. 9631000 or Essex SCD 551.2 or equivalent must be used in order to maintain original installation integrity. Apply clear glass primer, Essex SCD 435.18 or equiv­ alent around the entire perimeter of glass edge. Refer to Fig. 2D-102. Apply the black glass primer in the urethane adhesive kit 9631000 or Essex SCD 435.20 or equivalent around the entire perimeter of the glass edge. Allow to dry to LIG H T TR UC K SERVIC E M A N U A L BODY Fig. 2D-102 Windshield Installation Preparation 2D-41 5. With the aid of a helper, lift the glass into the opening. Carry the glass with one hand on the inside of glass, and one hand on the outside. At the windshield opening, set the glass in a horizontal position. While one partner holds the glass in this position, the other can reach one arm around the pillar and support the glass from the inside, while the first person assumes the same position. With the glass centered in the opening, place the glass against the inside support molding, use small rubber blocks to support the glass in the correct position. Use the last screw on either side of the cowl grille cover as a guide for the positioning of these blocks in the wind­ shield opening. Be sure to center the glass so that gaps on opposite sides and top-to-bottom are equalized. Trim rubber blocks as necessary. If the short method is used, check reveal molding fit and cut away additional solidified urethane base as necessary. See Fig. 2D-104. 6. Cut the tip of the adhesive cartridge to make asmall opening of approximately 3/16 inch. First, fill in behind and around spacer blocks with urethane. 7. Then apply a smooth, continuous bead of urethane. Direct the flow of urethane down into gap as shown in Fig. 2D-105. The material should fill the gap between the glass edge and the sheet metal. If necessary, use a flat-bladed instrument to paddle material into position. Be sure that adhesive contacts the entire edge of the glass, and extends to fill the gap between the glass and primed sheet metal or solidified urethane base from the original installation. 8. Spray a mist of water onto the urethane. This adhesive is moisture curing. W ater will assist in the curing process. Dry the area where the reveal molding will contact the glass and the body. Fig. 2D-103 Support Molding Installation touch (approximately 10 minutes). Refer to Fig. 2D102. 9. To install the outside reveal moldings. If new moldings are installed, remove the protective tape covering the butyl adhesive on the underside of the molding. If the original moldings are reusable, remove any excessive butyl or urethane. Push molding caps on to either end of one of the reveal moldings. Press the molding retention lip into the urethane adhesive against the edge of the windshield as shown in Fig. 2D-106 taking care to seat the molding in the corners. Be sure the lip LIG H T T R U C K SERVICE M AN U AL 2D-42 BODY Fig. 2D-105 Adhesive Material Application fully contacts the adhesive all around and that the gap is entirely covered by the crown of the molding. Slide molding caps into position between moldings connect­ ing them. Use tape to hold the molding down in the correct position against the body and glass until the adhesive cures. 10. Install wiper arms, and clean up surrounding areas as required. Vehicle should not be driven and remain at room te m p e ra tu re for six hours to allow proper cure of adhesive. 11. W ater leak test the vehicle. If a leak is found, refer to Windshield W aterleak Correction procedure. WINDSHIELD WATERLEAK CORRECTION W ith the u reth ane bonded glass on the G model, waterleaks can be corrected without the removal of the reveal moldings or glass from inside the vehicle. Removal of the garnish and support molding will expose the urethane bond from the glass to the body. Refer to Fig. 2D-107. 1. Remove garnish molding if so equipped. 2. Remove the windshield support molding from the pinchweld. Pry up one end and pull the molding away from the pinchweld. 3. Identify cause and location of the leak. If the leak is due to a disruption in the urethane bond to the glass, the leak can be repaired with addition urethane adhesive. Use the adhesive m aterial furnished in Kit. No. 9631000 or Essex 551.2 or equivalent. NOTICE: W ater may be leaking through a pinchweld seam and not the urethane bead. In these instances, the entry point must be determined and correction made at that point in the pinchweld. (Voids in roof gutter sealer may also produce this type of leak.) LIG H T T R U C K SE RV IC E M A N U A L 4. Clean up any dirt, foreign material or loose urethane in the area of 3 to 4 inches on either side of the point of the leak. Make sure the area is dry. 5. Prime this area with the primer found in the urethane adhesive Kit. No. 9631000 or Essex SCD 435-20 or equivalent. Thoroughly agitate the primer before using. Allow the primer to dry for five minutes. 6. Apply the urethane adhesive to the prepared area. Use a flat stick or other suitable flat bladed tool to work the adhesive material well into the leak point and onto the original material to obtain a water-tight seal. 7. Using warm or hot water, leak test to assure that the leak has been corrected. 8. Install the support molding immediately. SWINGOUT WINDOW Replacement 1. Swing out the window. See figure 2D-109. 2. Remove screws retaining latch to body. 3. Remove window by swinging glass out, separating assembly at hinge. 4. Remove latch from glass by twisting and pulling out. 5. Reverse removal procedure to install swingout window. BODY 2D-43 ^A D H E S IV E TO WEATHERSTRIP AND PINCHWELD LATCH SWINGOUT WINDOW Replacement 1. Swing out the window. 2. Remove latch to body attaching screws. 3. Twist and pull latch to remove from glass. 4. Reverse above steps for installation. FRONT DOOR DOOR ADJUSTMENTS Doors can be adjusted for alignment of clearance in the cab door opening, and for proper latching. Door alignment adjustments are made at the striker bolt, and at door hinges. T he door, when properly located in door opening, will have equal clearance around its perimeter. The door should be adjusted in the opening so the edge of the door across the top and also at the lock side is parallel with the body opening as nearly as possible. Hinge Adjustment Door hinge bolt holes are oversized to make adjustment possible. Alignment adjustments can be made by loosening the proper hinge bolts, aligning door to proper position, and tightening bolts securely. See figure 2D-110, for typical adjustments. Striker Bolt Adjustment With the use of J-23457, shown in figure 2 D -1 11, the striker bolt can be adjusted in any of three ways. See figure 2D-112. 1. Up and dow n-To adjust striker up or down, loosen bolt, adjust to center of lock entry, and tighten bolt securely. This adjustment is important to assure that the right proportion of door’s weight will rest on striker bolt when door is closed. If bolt is positioned too high on pillar, rapid wear will occur to the lock cam; if too low, L IG H T T R U C K SERVICE M AN U AL 2D-44 BODY an extra load will be placed on door hinges as well as pulling door downward and out of alignment. 2. In and Out-To adjust striker in and out, loosen bolt, adjust horizontally to match the door surface to the body surface, and tighten bolt securely. 3. Forward and Rearward-To m ake this adjustm ent, loosen striker bolt, shim to desired position, and tighten bolt securely. DOOR HINGE Remove 1. Remove hinge access hole cover from door hinge pillar. 2. If removing one hinge, support door in such a manner that weight is taken off other hinge, and that the door will not move. 3. Remove hinge screws from both body and from door and remove hinge. See figure 2D -110. Installation 1. Install hinge to door and body. Snug bolts. 2. Remove door supports. 3. Adjust door as outlined under "Door A djustm ent". 4. Torque bolts to specifications. 5. Install hinge access hole covers. DOOR WEATHERSTRIP Success of weatherstrip replacement depends entirely upon the quality of the cement used and the care with which it is applied. All rust, road dirt and grease or oil must be completely removed as should all old cement and bits of old weatherstrip. After removing all foreign material from door opening surface, wipe down with prepsol or its equivalent. Use only a good quality cement which is made specially for w eatherstrip installation, following the m a n u f a c tu re r ’s directions. Proceed as follows: 1. Open door and block open. 2. Remove side door weatherstrip. 3. Remove used adhesive from door with adhesive or cement remover, and remove all plastic nails. 4. Apply adhesive to door. 5. Position weatherstrip by locating part number at top of vent window, making sure that plastic nails align with holes in door. 6. Install weatherstrip by pressing each nail into the door. TRIM PANEL, ARM REST AND HANDLES Removal 1. Remove screws retaining arm rest to trim panel. 2. Remove door and window handles with Tool J-9886-01 and pull from shaft. 3. Remove trim panel screws and remove panel. If plastic water shield seal is damaged, replace seal. Installation 1. Install trim panel. 2. Install arm rest. Install door and window handle washers and handles. DOOR VENTILATOR ASSEMBLY Removal Fig. 2D-111--Loosening Striker Bolt LIG H T T R U C K SE R V IC E M A N U A L The channel between the door window glass and door vent is removed as part of the vent assembly. BODY 1. R egu late the door window glass to the full down position. 2. Remove door and window handles with Tool J-9886-01. 3. Remove trim panel and water shields. 4. Remove rear window run channel screws. 5. Slide door window glass rearw ard away from ventilator. 6. Remove three screws at the upper front of the door and lower forward channel screw, as shown in figure 2D113. 7. Pull the upper portion of the ventilator rearward. 8. Turn the vent assembly 90° and carefully remove by guiding up and out, as shown in figure 2D -114. 2D-45 Ventilator Glass Replacement 1. Using an oil can or similar means, squirt prepsol on the glass filler all around the glass channel or frame to soften the old seal. When the seal has softened, remove the glass from the channel. 2. Thoroughly clean the inside of the glass channel with sandpaper, removing all rust, etc. 3. Using new glass channel filler, cut the piece to be installed two inches longer than necessary for the channel. Place this piece of filler (soapstoned side of filler away from glass) evenly over the edge of the glass which will fit in the channel. The extra filler extending beyond the rear edge of the glass should be pinched together to hold it in place during glass installation. One side of this filler (the outside of the roll) is soapstoned. This is the side which goes into the metal channel. 4. Brush the inside of the metal glass channel freely with ordinary engine oil. This will enable the glass and filler to slide freely into the channel. Glass should be installed so that rear edge is parallel to the division post. Allow full cure before water testing. Installation Replace the door window glass and regulate to the full down position before installing the door ventilator assembly. 1. Lower the ventilator assembly into the door frame. Center into position. 2. M ake certain the rubber lip is positioned before tightening screws. 3. Slide door glass forward engaging glass in vent channel. 4. Reinstall all screws and tighten. 5. Install and tighten the three screws at the upper front of the door. Adjustment 1. Adjust the ventilator adjusting nut by turning clock­ wise to increase operating tension, as shown in figure 2D-115. 2. After making adjustment bend tabs over the hex nut. 3. Install trim panel. 4. Install door and window regulator handles. DOOR WINDOW ASSEMBLY Replacement 1. 2. 3. 4. 5. Completely lower glass to bottom of door. Remove door arm rest, trim pad and water shields. Mask or cover upper portion of door window frame. Remove ventilator assembly as previously outlined. Raise window until regulator arms are level with access hole in door. 6. Slide glass forward until front roller is in line with notch in sash channel. Disengage roller from channel. See figure 2D -116. 7. Push window forward and tilt front portion of window up until rear roller is disengaged. Fig. 2D-114--Removing Ventilator 8. Put window assembly in normal position (level) and raise straight up and out. I IfiU T TOI yC'Y CFD \^irr - 2D-46 BODY 5. Push regulator out of door opening while holding rear of assembly, then slide assembly to the notches in the carrier channel and out through the door access hole. 6. Install regulator in reverse order of removal, lubricate regulator gears with lubriplate or equivalent. WINDOW REGULATOR - POWER In the case th a t window will not operate, check electrical connections first. Figure 2D-118 illustrates loca­ tion of junctions, switch, relay and circuit breaker. Replacement CAUTION:Electrical connectors must be removed from window lift motor before performing any operation on the regulator, or personal injury could occur. Fig. 2D-115--Adjusting Ventilator Tension 9. Reverse above procedure for installation. DOOR W INDOW ADJUSTMENT 1. 2. 3. 4. 5. To perform the adjustments listed, the door trim panels must be removed. CAUTION:Step 6 must be performed when reg­ ulator is removed from door. The regulator lift arms are under tension from the counterbalance spring and can cause serious injury if the motor is removed without locking the sector gear in position. Glass Height (Fig. 2D -116) Loosen the bolt and adjust the stop assembly located above the regulator sprocket so that the glass height in the lowered position is flush with the top of the sill, then tighten stop assembly bolt. Regulator Raising and Lowering Effort (Fig. 2D-109) The lower bolt on the run channel assembly provides fore and aft movement to ease regulator effort. WINDOW REGULATOR - MANUAL Replacement 1. 2. 3. 4. Wind window all the way up. Remove inside door handles with Tool J-7797. Remove door trim pad. Remove screws securing regulator to inner panel. Disconnect battery ground cable. Remove door trim panel. Disconnect harness from regulator. Remove screws securing regulator to inner panel. Push regulator out of door opening while holding rear of assembly, then slide assembly to the notches in the carrier channel and out through the door access hole. 6. Drill a hole through the regulator sector gear and back plate. DO N O T drill hole closer than 1/2" (12.7mm) to edge of sector gear or back plate. Install a pan head sheet metal tapping screw (No. 10 - 12 x 3/4) in drilled hole to lock sector gear in position. 7. Remove motor to regulator attaching screws. 8. Remove motor from regulator. 9. Prior to installation, lubricate the motor drive gear and regulator sector teeth. The lubrication used must be cold weather approved to a minimum of minus 20° fahrenheit (-29°C). 10. Install regulator motor to regulator. Make sure the motor pinion gear teeth mesh properly with the sector gear teeth before installing the three motor attaching screws. 11. Remove screw locking sector gear in a fixed position. 12. Install regulator in reverse order of removal, lubricate regulator gears and rollers with lubriplate or equivalent. DOOR LOCK-FIGURE 2D -118 Removal 1. 2. 3. 4. 5. Raise window. Remove inside handles with Tool J-9886-01. Remove trim panel. Remove door lock knob. From outside the door remove screws retaining lock to door edge and lower the lock assembly. 6. Remove screws retaining remote control. 7. Remove screws securing glass run guide channel. y-gH’f W 'tfx nsMv’CK v M im BODY 2D-47 Fig. 2D-117--Power W indow and Power Door Lock W iring 8. Remove lock, push button rod and remote control rod as an assembly. R EM O TE Installation LO C K 1. Transfer remote rod with clip to new lock. 2. Connect remote door handle rod to lock after lock is positioned. 3. Secure lock screws and glass run guide channel. 4. Secure remote handle. 5. Check all controls for proper operation before reinstall­ ing trim and handles. 6. Install door lock knob. REMOTE CONTROL AND CONNECTING ROD-Fig. 2D-118 Replacement 1. Raise door window and remove door trim pad. 2. Remove bolts securing remote control to door inner panel. Rod and c lip m ust be to lo c k asm before lo ck asm is installed to door. 3. Pivot remote inboard slightly, to disengage connecting rod, and remove remote control from door. Connecting rod can be removed at this point by disconnecting spring clip from lock. 4. To install, reverse removal procedure. Fig. 2D-118--Lock and Remote Control Assembly LIG H T T R U C K SERVICE M AN U AL 2D-48 BODY POWER DOOR LOCKS The power door lock system incorporates a motor a c tu a to r in each door which actuates the lock through linkage (fig. 2D-120). See Figure 2D-117 for switches, relay and wire routing. Replacement 1. Disconnect battery ground cable. 2. Remove door trim panel to gain access to power door lock motor. 3. Disconnect electrical connector from motor. 4. Remove screws attaching motor to door inner panel. 5. Remove door lock lever from rubber mount at top of motor actuator and remove motor through access hole. 6. To install, reverse steps 1 through 5 above. LOCK CYLINDER ASSEMBLY-FIG. 2D -119 Replacement 1. Raise door window and remove door trim pad. 2. With a screwdriver, or other suitable tool, slide lock cylinder retaining clip (on door outer panel) out of engagement and remove lock cylinder. 3. To install, reverse removal procedure. SLIDING SIDE DOOR DESCRIPTION The weight of the sliding side door is supported by the upper rear hinge-and-roller assembly, and by the lower front catch-and-roller assembly. The front and rear latches retain the door in the locked position, while the rear wedge assembly restricts door vibration on rough road surfaces. ADJUSTMENTS LIG H T TR UC K SE RV IC E M A N U A L NOTICE: See N O T I C E on page 1 of this section regarding all sliding door fasteners and adjustments found below. The side door can be adjusted for alignment and/or clearance in the body opening and for proper latching. When properly positioned in the body opening, the door should have equal clearances around its perimeter. Adjust­ ments for door positioning and proper latching can be made at the locations shown in figure 2D-121. BODY 2D-49 W INDO W SWITCH AS S E M B LY DOOR LOCK SW ITCH REAR DOOR M OTO R ACTUATOR (DOOR LOCK) MOTOR (POWER W INDOW ) SW ITCH CONTACT (DOOR) SWITCH CO NTACT (PILLAR ) Fig. 2D-120--Power Door Lock Actuators, Power Window Motor, Wiring and Switches LIG H T T R U C K SERVICE M A N U A L 2D-50 BODY STRIKER F O R E - A N D -A F T A D J U S T M E N T S L O T S C E N T E R ROLLER VERT ICA LLY IN T R A C K S O IT D O E S N O T CONTACT THE T R A C K IN FULL O P E N U P -A N D -D O W N O R FULL A D J U S T M E N T SLO T S CLOSED -------- ^ ... . .., .. J1 ^ 1 P O S IT IO N UPPER REAR HINGE-AND-ROLLER SECTION B-B TOP VIEW UPPER LE V E R .___.L O W E R LEVER U P -A N D -D O W N A D JU ST M EN T SLO TS / j f / STRIKER, U PPER F R O N l Y N in -a n d -o u t ROLLER ASSEMBLY) adJustment; FRONT LATCH STRIKER FACE VIEW G U ID E U P -A N D -D O W N A DJU STM EN T IN - A N D -O U T ADJUSTM EN T R U B B E R '" C U S H IO N LATCH SECTION C-C LOWER ROLLERS i AND CATCH ASM REAR ' REAR LATCH WEDGE | N ^ S T R IK E R ASSEMBLY . SECTION E-E HOLD-OPEN i CATCH Fig. 2D-121 —Sliding Side Door Adjustment Locations LIG H T T R U C K SERVICE M A N U A L BODY 2D-51 Up and Down Fore and Aft Up and down adjustments are provided by means of slotted holes located at the upper front roller, view B of figure 2D-121; at the lower front.catch-and-roller, view D; and at the upper rear hinge-and-roller assembly, view A. To reposition the door up or down: 1. Partially open door and loosen front latch striker on pillar. 2. Remove upper rear hinge cover, shown in figure 2D- Fore and aft adjustment is provided at the upper rear hinge striker by means of a slotted bracket mounted to the body, view A of figure 2D-121. 122 . 3. Loosen upper rear hinge-to-door bolts. 4. Loosen rear lock striker and door wedge assembly. 5. Align rear edge of door up or down, then tighten upper rear hinge-to-door bolts to specifications. 6. Loosen upper front roller bracket-to-door bolts. 7. Partially close door and align front edge of door up or down by loosening front lower hinge-to-door bolts. When door is correctly positioned, tighten bolts to specifications. 8. Position upper front roller in center of track, then tighten roller bracket to door. 9. Adjust front and rear strikers and rear wedge assembly as outlined in their respective procedures later in this section. In and Out Front in and out adjustments are provided by means of an adjustable lower roller mounting bracket, view D of figure 2D-121, and by a slotted upper bracket, view B of figure 2D-121. Rear in and out adjustment is provided by adjusting the rear latch striker, view E of figure 2D-121. To position the door in or out: 1. Loosen front latch striker. 2. Loosen upper front roller from its bracket. 3. Loosen lower front roller bracket-to-arm bolts. 4. Adjust front of door in or out, then tighten bolts to specifications. 5. A djust door hold open catch bracket, rear wedge assembly, rear latch striker, upper front roller and front latch striker as outlined later in " Adjustments ". 1. Partially open door and remove front latch striker and rear lock striker. 2. Loosen rear wedge assembly. 3. Remove upper rear track cover. 4. Loosen upper rear hinge striker. 5. Move door assembly forward or rearward, then tighten striker bolts to specifications. 6. Reinstall upper rear track cover. 7. Reinstall front and rear latch strikers. 8. A djust latch strikers and rear wedge assembly as outlined below. Latch Striker Adjustments Front Striker 1. Loosen front latch striker screws, view C of figure 2D121. 2. Visually align latch-to-striker relationship and adjust if necessary. 3. Slide door slowly toward striker. The guide on the door, just above the latch, must fit snugly within the rubberlined opening on the striker assembly. 4. Assure that the latch engages fully into the striker. Add or delete shims behind the striker as necessary. 5. Tighten striker screws to specified torque. Rear Striker 1. Loosen striker with J-23457. 2. Loosen rear wedge assembly. 3. Center the striker vertically to door striker opening. 4. Adjust the striker laterally to match outer panel to the body panel surfaces, view E of figure 2D-121. 5. Apply grease to the striker. 6. Gently push the door in until the rear lock contacts the striker enough to make an impression in the grease. 7. Open the door and measure the distance from the rear of the striker head to the impression. The distance should be between .20 inch (5mm) and .30 inch (8mm). Refer to view E of figure 2D-121. 8. Adjust position of striker by adding or deleting shims between the striker and the pillar. 9. Adjust rear wedge assembly as outlined later in this section, and torque all fasteners to specifications. Upper Rear Hinge-To-Striker Adjustment NOTICE: If door has been removed and is being reinstalled, adjust striker-to-lower hinge lever before closing door. Failure to do so may cause possible lever breakage. The upper rear hinge must be positioned as shown in view A of figure 2D-121, in order to insure proper latching. 1. The hinge lower lever must contact the striker at least .06 inch above the lower edge of the striker tang. LIG H T T R U C K SERVIC E M A N U A L 2D-52 BODY 2. The lower lever must extend at least .10 inch (2.5mm) outb oard of the striker tang. Add or delete shims between the striker and the body as necessary. 3. If necessary to shim roller away from guide, shims are added between the nylon block and hinge and between roller and hinge. They must be installed in pairs. For example, if one shim is added behind the nylon block another must be added behind the roller. Door Hold-Open Catch Adjustment This catch, mounted on the lower front roller bracket, holds the door in the full open position. See figure 2D-123. The catch engages a striker installed at the rear of the lower roller channel, view D of figure 2D-121. 1. Loosen the screws retaining the catch rod bracket to bottom of door. 2. Adjust catch -to -strik er engagem ent by sliding the bracket laterally. Catch should fully engage striker. Rear Wedge Assembly Adjustment 1. Loosen screws attaching rear wedge assembly to the body pillar, then close the door to the fully latched position. 2. Center the wedge assembly on the door wedge, as shown in figure 2D-124, and scribe a line around the wedge assembly. 3. Open the door, and move the wedge assembly 3/16 inch. FRONT LATCH ASSEMBLY Removal 1. 2. 3. 4. Remove trim panel, if so equipped. Remove access cover. Unscrew door lock knob from rod. Disconnect the following rods from latch, shown in figure 2D-125. a. Rear latch rods. b. Lock cylinder rod. c. Door lock rod. 5. Remove door handle. 6. Remove screws retaining latch assembly to door. 7. Slide latch rearward and lift front of latch. Disconnect rod leading to lower hinge door catch by pushing rod out of hole and rotating rod clear of latch. 8. Remove latch assembly from door. Installation 1. Install latch assembly into door by working latch assembly behind the lower hinge door catch. 2. Connect lower hinge door catch, lock cylinder rod, door lock rod, and both rear latch rods. 3. Install latch assembly-to-door Torque to specifications. attaching screws. 4. Install door lock knob and door handle. 5. Install access cover and trim panel. Fig. 2D-123--Hold-Open Catch LIG H T T R U C K S F R V irF M AN U AI BODY 2D-53 Fig. 2D-127~Rear Track Cover Fig. 2D-126--Sliding Door Rear Latch 6. A d ju st door front strik e r as outlined earlier under "A d ju stm en ts". 4. A djust re ar latch strik er as outlined earlier under "A djustm ents". UPPER REAR HINGE Removal REAR LATCH AND/OR LATCH ACTUATING RODS Removal 1. Remove trim panel (if so equipped). 2. Remove front latch assem bly access cover. 3. Disconnect rear latch rods from front latch assembly, shown in figure 2D-125. 4. Remove rear latch attaching screws. See figure 2D126. 5. Slide rear latch tow ard front of door until rod clips become exposed. Disconnect rod clips and remove latch from door. Installation 1. Connect rods to latch and install latch to door. Torque screws to specifications. 2. Connect rods to front latch assembly. 3. Install access covers and trim panels (if so equipped). LIG H T T R U C K SERVICE M A N U A L 1. Remove the hinge cover and rear track cover. See figures 2D-122 and 2D-127. 2. Open the door. 3. Disengage spring from bolt, using a spring removal tool. 4. Close the door. 5. Remove the hinge assembly. Installation W hen holding hinge assembly as in figure 2D-129, the lower latch must engage cam. 1. Install hinge assem bly to door. T orque bolts to specifications. 2. Check and adjust latch to striker position as outlined under "A djustm ents". 3. Open the door and reconnect the hinge spring. 4. Install the rear track cover and hinge cover. 5. Check the operation of the door hinge. 2D-54 BODY 1. 2. 3. 4. 5. 6. 7. Roller Lockwashers Nut Cam Washer Bushing Bushing 8. 9. 10. 11. 12. 13. 14. Bolt 15. Plate 16. Upper lines 17. Spacer 18. Spring (Upper Lever) 19. Spring (Lower Level) 20. Lower Lever Screw Guide Block Hinge (Body Half) Nut Bushing Bushing 21. 22. 23. 24. 25. 26. Cam Bushing Hinge (Door Half) Spring Spring retainer Hinge liner Fig. 2D-128--Upper Rear Hinge Components LIG H T T R U C K SERVICE M A N U A L BODY 2D-55 STRIKERS The front and rear strikers are shown in figure 2D-121. The rear striker can be removed with J-23457 as in figure 2 D -1 11, and the front striker can be removed by removing a tta ch in g screws. R efer to "A d ju stm en ts" when reinstalling. REAR DOORS REAR DOOR HINGE STRAP 3. Remove hinge-to-door bolts and remove door assembly. Remove hinge-to-body bolts and hinge. 4. Replacement 1. Remove strap release pin. See figure 2D-130. 2. Remove screws retaining strap to door. 3. Install stra p to door. T orque retain in g screws to specifications. REAR DOOR HINGE Removal 1. Open door. Support door so th a t when hinge screws are removed door weight will be on support. 2. Remove hinge strap release pin. Installation 1. Install grom m et into door hinge opening (if removed). 2. Install hinge into door. Snug bolts. 3. Install seal and retainer on body half of hinge (if removed). 4. Install hinge into body opening and install bolts. 5. Take care to compress seal between body and retainer and snug bolts. 6. Install hinge strap and its retaining pin. 7. Adjust door and torque hinge bolts to specification. REAR DOOR REMOTE CONTROL Removal 1. Remove trim panel. 2. Disengage upper and lower latch rods from control by remmoving retaining clips. See figure 2D-131. 3. Remove rem ote control by rem oving its retaining screws. Installation 1. Install remote control screws loosely. 2. A ttach upper and lower control rods. 3. R otate remote control lever clockwise, and hold in this position while torquing the screws to specifications. 4. Install the trim panel. REAR DOOR UPPER OR LOWER LATCHES A N D / OR LATCH RODS Removal 1. Remove trim panel. 2. D isengage rod from rem ote control assem bly. See figure 2D-131. LIG H T T R U C K SERVICE M A N U A L 2D-56 BODY 3. Remove lock cylinder retainer and lock cylinder. Installation 1. Install lock cylinder and retainer. 2. Install remote control. Torque screws to specifications. 3. Remove latch retaining screws and w ithdraw latch and control rod. 4. Remove spring clip retaining rod to latch. 3. Install trim panel. REAR DOOR GLASS AND WEATHERSTRIP Installation 1. Install latch rod to latch. W hen reinstalling the lower latch rod to control, the short straight section attaches to the latch. Removal and installation procedures are the same as for the statio n ary body side windows. R efer to those procedures for rear door glass and w eatherstrip replacem ent. 2. Install latch and rod assembly into door and connect rod to remote control. Lube all moving parts. REAR DOOR ADJUSTMENTS 3. Install latch specifications. Door adjustm ents are provided by slotted holes, at hinge attachm ent, in body and door. re ta in in g screws and torque to 1. Remove or loosen door strikers and wedges. 4. A djust latch to strikers. 2. Loosen door hinge bolts and adjust door to provide equal clearances between body and door around perim ­ eter of door. REAR DOOR OUTSIDE HANDLE Removal 1. Remove trim panel. 3. A djust door in and out so th at door panel is flush with body. 2. Rem ove door handle retain in g screws, handle and gaskets. See figure 2D-132. 4. Install door strikers and wedges and adjust as outlined under door striker adjustm ent. Installation REAR DOOR STRIKER AND WEDGE ADJUSTMENT 1. Apply grease to rem ote control where handle plunger makes contact. 2. Install handle specifications. and gaskets. 3. Install trim panel. REAR DOOR LOCK CYLINDER Removal 1. Remove trim panel. 2. Remove rem ote control. T orque screws to NOTICE: See N O T IC E on page 1 of this section regaring R ear Door Striker fasteners. 1. A djust striker by adding or deleting shims as necessary to obtain dimension as shown in figure 2D-133. This dimension can be checked by applying grease to the latch and slowly closing door until striker fully engages latch. T hen open door and m easure from grease im pression to bottom of latch slot. T orque to specifications. 2. Adjust door wedge by adding or deleting shims as necessary so that wedge contact ram p on body when door is closed. See figure 2D -133. LIG H T T R U C K SERVICE M AN U AI BODY Fig. 2D-133--Reor Door Striker and W edge Adjustment SEATS NOTICE: See N O T IC E on page 1 of this section regarding fasteners used on seats and seat belts. DRIVERS SEAT Seat Adjuster Replacement 1. Remove seat by removing nuts securing seat adjuster to seat riser. 2. Remove adjuster from seat. See figure 2D-134. 3. Install seat a d ju ste r specifications. to seat. T orque bolts to 4. Install seat onto seat riser, and torque nuts to specifications. SEAT RISER Replacement 1. Remove seat and adjusters as an assembly by removing nuts securing seat to riser. 2. Remove nuts securing seat riser to floor. 3. Install seat riser to floor. Torque nuts to specifications. 4. Install seat and torque nuts to specifications. LIG H T T R U C K SERVICE M A N U A L 2D-57 2D-58 BODY PASSENGER SEAT-MOUNTING BRACKETS Removal 1. Remove seat and brackets from seat riser. See figure 2D-135. 2. Remove brackets from seat. Installation 1. Install brackets to seat. T orque to specifications. 2. Install seat to seat riser. Torque to specifications. SEAT RISER Removal 1. Remove seat and m ounting bracket as an assembly. 2. Remove riser from floor. Installation 1. Install riser to floor. T orque nuts to specifications. 2. Install seat riser. Torque nuts to specifications. LIG H T T R U C K SERVICE M A N U A L 2D-60 BODY REAR BENCH SEATS All models equipped with 2nd, 3rd and 4th bench seat assemblies feature a quick release m echanism which facili­ tates removal of the seats for added cargo space. Instead of the conventional clam p and bolt m ethod of seat reten tio n , cam type latch assem blies and hooked retainers, which fit onto anchor pins in floor anchor plates are used. W hen the latch assemblies are depressed, their cams and the hooks of the retainers are draw n tightly onto the anchor pins for secure seat attachm ent. R em oval is accom plished using the following procedure: 1. Pull up on quick release latches located at lower front of seat legs (right and left hand sides). 2. Tilt up front of seat and push seat rearw ard to clear anchor pins located beneath floor at front and rear of seat legs. 3. Lift seat up and remove from van. 4. To replace, reverse steps 1 to 3. NOTICE: W hen replacing seats m ake sure th at seat retainer hooks are fully engaged with anchor pins and latching assembly is fully depressed into place. SWIVEL BUCKET SEATS - G MODELS R efer to the illustration in Figure 2D-137 for swivel Bucket S eat Assembly installation. ROOF VENT - G MODELS Roof vent installation is illustrated in Figure 2D-138. SERVICING LAP BELTS Service precautionary item s are outlined in the CK portion of this section. Internal drive thread-forming anchor bolts are used to secure lap belts to the floor pan. To remove or install internal drive anchor bolts, use door lock striker and lap belt anchor bolt removal tool J-23457 or equivalent. Start bolt by hand to assure that bolt is threaded straight. Refer to figures 2D-139 through 2D-141 and select the ap p ro p riate illustration for rem oving and installing lap belts. DECAL APPLIQUE PROCEDURE Refer to Section 2C, Chassis Sheet M etal, for proce­ dure relating installation of decals or stripes. ADHESIVE BODY SIDE MOLDING Refer to Section 2C, Chassis Sheet M etal, for proce­ dures relating to installation of adhesive moldings. LIG H T T R U C K SERVICE M A N U A L BODY LIG H T T R U C K SERVICE M A N U A L 2D-61 2D-62 BODY SPECIFICATIONS FRONT END TAILGATE-FLEETSIDE Sunshade Support.....................................18 in. lb. Outside Rear View Mirror lo Door Panel Base M irror.................................... 18 in. lb. West Coast Mirror Lower Bracket to Door................... 18 in. lb. Upper Bracket to Do o r ................... 18 in. lb. 2. N* m 2. N 'm Trunnion Assembly................................ 18 ft. lb. 24. N 'm Linkage and Striker AssemblySupport.................................................... 18 ft. lb. 24. N 'm 2. N-m 2. N 'm DOORS Window Regulator Assembly to Door Panel............................................85 in. lb. 9.5 N 'm Remote Control Door Lock to Door Panel........................................... 45 in. lb. 8. N 'm Lock Striker to Body Pillar................... 45 ft. lb. 60. N 'm Outside Door Handle................................ 85 in. lb. 9.5 N-m Inside Door Handle.................................. 85 in. lb. 9.5 N-m Hinges to Body and Do o r.........................31 ft. lb. 42. N- m Front Door-Window Rear Channel Upper Bolt Assem bly..................... 85 in. lb. 9.5 N-m Lower Bolt Assembly..................... 85 in. lb. 9.5 N-m Front Door-Ventilator and Glass Run Assembly Top Vent Screw................................ 20 in. lb. 2.2 N 'm Side Vent Screws and Spacers........22 in. lb. 2.5 N-m Lower Vent Channel Bolts............. 85 in. lb. 9.5 N-m Side Rear Door-Run Channel Front Upper Bolt to Door............... 85 in. lb. 9.5 N-m Rear Upper Screw to Door............. 20 in. lb. 2. N-m Front Lower Nut to Door.............. 45 in. lb. 5. N- m Rear Lower Bolt to Door............... 85 in. lb. 9.5 N-m Lock Lever to D o o r .......................85 in. lb. 9.5 N-m Rear DoorLock Striker (Suburban).........................19 ft. lb. 26. N-m Rear Door-Latch LH and RH to Door (Suburban)..................................85 in. lb. 9.5 N-m Rear Door-Latch Control Assembly to Door (Suburban) Upper Assembly............................. 19 ft. lb. 26. N-m Lower Assembly............................ 85 in. lb. 9.5 N-m END GATE Hinges-Body Half and Gate Half........... 35 ft. lb. 48. N-m Support Assembly-Cable Bolts............. 35 ft. lb. 48. N-m Torque Rod to Hinge Pocket................. 85 in. lb. 9.5 N-m Torque Rod to Body.......................... . 18 ft. lb. 2. N-m Latch Assembly to End Gate................. 33 ft. lb, 44. N 'm Latch Control Assembly to End Gate............................................. 45 in. lb. 5. N-m Handle to Latch Control Assembly........45 in. lb. 5. N-m Glass Channel (Suburban)......................45 in. lb. 5. N-m Glass Channel (Utility).......................... 85 in. lb. 9.5 N-m Outside Handle........................................55 in. lb. 6. N-m Cap Assembly to Channel Assembly... .24 in. lb. 2 .6 N-m Striker-Body Mounted............................ 25 ft. lb. 34. N-m TAILGATE-STEPSIDE Trunnion Assembly..................................18 ft. lb. 24. N-m Chain Support Assembly..........................90 in. lb. 10. N-m SEATS Front Bench Seat Adjuster-to-Seat.......................... 50 in. lb. Adjuster-to-Floor........................ 25 ft. lb. Front Bucket Type Driver Adjuster-to-Seat................. 18 ft. lb. Adjuster-to-Floor............... 25 ft. lb, Passenger Chassis Cab Support-to-Seat................... 18ft. lb. Support-to-Floor (Front)..................................25 ft. lb. Support-to-Floor (Rear)....................................40ft. lb. Passenger Suburban Latch Support to Seat (Rear).......................18 ft. lb. Striker to Floor (Rear)..................................25 ft. lb. Support (Upper) to Seat (Front).....................18 ft. lb. Support (Lower) to Floor (Front)................... 25 ft. lb. Support (Upper) to Support (Lower)............. 30 ft. lb. Rear Bench Utility, Suburban Support-Lo-Seat............................ 18 ft. lb. Support-to-Floor.......................... 50ft. lb. Rear Bench Crew Cab Support-to-Seat.......................... 150 in. lb. Support-to-Floor.......................... 35 in. lb. Folding Rear Seat Suburban Support Asm-to-Floor................. 150 in, lb. Seat-to-Support A s m .....................18 in. lb. 17. N-m 34. N 'm 24. N-m 34. N-m 24. N-m 34. N-m 54. N-m 24. N 'm 34. N-m 24. N-m 34. N-m 40. N-m 24. N-m 70. N-m 17. N-m 17. N 'm 24. N-m Keyliner Chart 2D-A--Specifications LIG H T T R U C K SERVICE M AN U AL BODY 2D-63 BODY MOUNTING (C-K MODELS) MODEL #2 #1 CHASSIS C A B 55 ft. lb. 75 N- m 55 ft. lb. 75 N- m C R E W CAB 55 ft. lb. 75 N- m 35 ft. lb. 48 N- m SU B U R B A N 55 ft. lb. 75 N*m 35 ft. lb. 48 N-m U TILITY 55 ft. lb. 75 N-m 45 ft. lb. 60 N .m #3 #4 #6 #5 55 ft. lb. 75 N- m 35 ft. lb. 48 N-m 35 ft. lb. 48 N- m 35 ft. lb. 48 N* m 35 ft. lb. 48 N- m G MODELS MIRRORS AND SUNSHADE SLIDING SIDE DOOR Outside Rear View Mirror to Panel... .150 in. lb. 17. N-m Sunshade Support to Header Panel-lb. 1.6 N-m SIDE WINDOW (SWINGOUT) Latch to Body........................................ Hinge to Body........................................ lb 4 .6 N*m lb. 6 .0 N-m r HUN 1 blUfc U U U K d Door Hinges.......................................... Remote Control Retaining Screws . . . . . .45 in. Door Lock Striker................................ .. 45 ft. Door Lock to D o o r .............................. Outside Door Handle............................ . .90 in. Regulator Assembly............................. 40. N-m 5. N-m lb. lb. 60. N-m lb. 30. N-m lb. 10. N-m 10. N-m REAR DOOR Hinge (to body and door)....................... Remote Control RH Retaining Screws.................................. Latch-to-Door Retaining Screws Upper........................................ Latch-to-Door Retaining Screws Lower........................................ Door Strikers-to-Body......................... Outside Door Handle............................ . .40 ft. lb. 54. N 'm ..7 0 in.lb. 8. N- m . . 19 ft. lb. 26. N-m ..7 0 in. lb. 8. N-m ..1 8 ft. lb. 24. N-m ..9 0 in. lb. 10. N-m Remote Control (front latch) Rear Latch to Door.................................. Lower Front Roller and Roller Support Support-to-Door................................ . .24 ft. Support to Roller Bracket............... ..2 4 ft. Lower Control Assembly................. Upper Front Roller Bracket Bracket to Do o r................................ 24 ft. 20 ft. Roller to Bracket.............................. Hinge to D o o r .................................... Upper Rear Hinge (Body Half) Roller to Hinge.................................. Guide Block to Hinge......................... Lever Arm-to-Hinge Retaining N u t .................................... Lever Retaining Screw ..................... Rear Striker to Body (Upper Stop).......... Rear Striker Bolt (Body Mounted).......... Front Striker Retaining Screws (Body Mounted)........................................ Keyliner Chart 2D-B--Specifications LIG H T T R U C K SERVICE M A N U A L SEATS Seat Belt to S ea t...................................... Passenger and Drivers Seat to Adjuster (Mounting Bracket).......................... Seat to Riser...................................... Seat Riser-to-Floor......................... Bench Seats Seat to Seat Support........................ Seat Support to Leg Assembly.......... lb. 10. N* m lb. 10. N* m lb. 32. N* m lb. 32. N ’ m lb. 10. N* m lb. 32. N 'm lb. 27. N* m ..2 5 ft. lb. 34. N* m . .20 ft. lb. 27. N ‘ m b. N- m .120 in. lb. 14. N ‘ m lb. 5. N 'm . .20 ft. lb. 27. N* m ..4 5 ft. lb. 60. N- m 10. N- m ..3 7 ft. lb. 50. N* m ..1 8 ft. lb. 24. N ‘ m . .18 ft. lb. 24. N* m . .50 ft. lb. 70. N ‘ m . .18 ft. lb. 24. N* m .130 ft. lb. 170 N- m 2D-64 BODY SPECIAL TOOLS 1. 2. 3. 4. J-2 25 85 J-22577 J-7797 J-23457 Front Door Hinge, Bolt Wrench Windshield Checking Blocks Door Handle Clip Remover Door Striker Bolt Remover and Installer Fig. 2D-143--Special Tools LIG H T T R U C K SE RV IC E M AN U AL FRONT ALIGNMENT 3A-1 SECTION 3A FRONT ALIGNMENT CONTENTS G eneral D escrip tio n.................. M aintenance and A djustm ents S pecifications............................... 3A-1 3A-2 3A-5 GENERAL DESCRIPTION FRONT ALIGNMENT T he term "fro n t alig n m en t" refers to the ang ular relationships between the front wheels, the front suspension attaching parts and the ground. The pointing in or "toe-in" of the front wheels, the tilt of the front wheels from vertical (when viewed from the front of the vehicle) and the tilt of the suspension members from vertical (when viewed from the side of the vehicle), all these are involved in front alignm ent. The various factors th at enter into front alignm ent are covered here each one under its own heading. CASTER C aster is the tilting of the front steering axis either forward or backward from the vertical (when viewed from the side of the vehicle). A backward tilt is said to be positive ( + ) and a forward tilt is said to be negative (-). On the short and long arm type suspension you cannot see a caster angle without a special instrum ent, but you can understand th at if you look straight down from the top of the upper control arm to the ground you would find that the ball joints do not line up (fore and aft) when a caster angle other than 0° is present. If you had a positive caster angle the lower ball joint would be slightly ahead (toward the front of the vehicle) of the upper ball joint center line. In short then, caster is the forward or backward tilt of the steering axis as viewed from a side elevation. Caster is designed into the front axle assembly on all K series vehicles (four-wheel drive), and is non-adjustable. See caster copy under A D JU S T M E N T S . CAMBER Cam ber is the tilting of the front wheels from the vertical when viewed from the front of the vehicle. W hen the wheels tilt outward at the top, the cam ber is said to be positive ( + ). W hen the wheels tilt inward at the top, the cam ber is said to be negative (-). The am ount of tilt is m easured in degrees from the vertical and this m easurem ent is called the cam ber angle. C am ber is designed into the front axle assembly of all K series vehicles and is non-adjustable. See cam ber copy under A D JU ST M E N T S. TOE-IN Toe-in is the turning in of the front wheels. The actual am ount of toe-in is normally only a fraction of an inch. The purpose of a toe specification is to ensure parallel rolling of the front wheels. (Excessive toe-in or toe-out will cause tire wear). Toe-in also serves to offset the small deflections of the wheel support system which occurs when the vehicle is rolling forward. In other words, even when the wheels are set to toe-in slightly when the vehicle is standing still, they tend to roll parallel on the road when the vehicle is moving. See toe-in copy under A D JU S T M E N T S . L IG H T T R U C K SE RV IC E M AN U AL 3A-2 FRONT ALIGNMENT (J. OF WHEEL DIRECTION CAMBER ANGLE CASTER ANGLE FRONT V IE W SIDE V IE W Fig. 3A-1--Caster - Camber - Toe-In MAINTENANCE AND ADJUSTMENTS PRELIMINARY CHECKS PRIOR TO ADJUSTING FRONT ALIGNMENT Before m aking any adjustm ent affecting caster, cam ­ ber or toe-in, the following checks and inspections should be m ade to insure correctness of alig n m en t readings and alignm ent adjustm ents. 1. C heck all tires for proper inflation pressures and approxim ately the same tread wear. 2. Check front wheel bearings for looseness (.001-.008 end play is correct) and adjust if necessary. 3. Check for looseness of ball joints, tie rod ends and steering relay rods; if excessive looseness is noted, it m ust be corrected before adjusting. 11. Consider the condition of the equipm ent being used to check alignm ent and follow the m a n u fa c tu re r’s instructions. 12. Regardless of equipm ent used to check alignm ent, the vehicle must be on a level surface both fore and aft and transversely. 13. Steering and vibration com plaints are not always the result of improper alignm ent. An additional item to be checked is the possibility of tire lead due to worn or improperly m anufactured tires. "L e a d " is the devia­ tion of the vehicle from a straight path on a level road without hand pressure on the steering wheel. Section 3E of this m anual, "W heels and T ires", contains a procedure for determ ining the presence of a tire lead problem. 4. Check for run-out of wheels and tires. 5. Check dimension A in Fig. 3A-4; if out of specifications and a correction is to be m ade, the correction must be made before adjusting caster. 6. Check for steering gear looseness at frame. 7. Check for improperly operating shock absorbers. 8. Check for loose control arm s. 9. Check for loose or missing stabilizer bar attachm ents. 10. Consideration m ust be given to excess loads, such as tool boxes. If this excess load is normally carried in the vehicle, it should rem ain in the vehicle during align­ ment checks. LIG H T T R U C K SE RV IC E M A N U A L FRONT ALIGNMENT REQUIREMENTS Satisfactory vehicle operation may occur over a wide range of front end wheel alignm ent settings. Nevertheless, should settings vary beyond certain tolerances, readjust­ ments of alignm ent is advisable. The specifications stated in column 1 of the chart in the specifications section of this m anual should be used by owners, dealers and repairm en as guidelines in vehicle diagnosis either for repairs under the new vehicle w arranty or for m aintenance service at custom ­ er’s request. These specifications provide an acceptable allaround operating range in that they prevent abnorm al tire wear caused by wheel alignm ent. FRONT ALIGNMENT G overnm ental Periodic M otor V ehicle Inspection program s usually include wheel alignm ent among items that are inspected. To provide useful inform ation for such inspections, the specifications stated in column 2 of the wheel alignm ent ch art are given and these are well within the range of safe vehicle operation. In the event the actual settings are beyond the specifi­ cations set forth in column 1 or 2 (whichever is applicable), or whenever for other reasons the alignm ent is being reset, the specifications given in column 3 of the wheel alignm ent chart should be used. It is good p ractice to set front end alignm ent to specifications while the vehicle is in its normally loaded condition. T rucks which are consistently operated with heavy loads should have toe-in adjusted with the truck under heavy load. This procedure should result in longer tire life. ALIGNMENT ADJUSTMENTS Caster All caster specifications are given assum ing a frame angle of zero. Therefore, it will be necessary to know the angle of the fram e (whether "u p " in rear or "dow n" in rear) before a corrected caster reading can be determ ined. C am ber and toe can be read "as is" from the alignm ent equipment. How to Determine Caster (Fig. 3A-4) All caster specifications are given assuming vehicle fram e angle is zero. Therefore, it is necessary to adjust specifications when applying them to vehicles w ith any fram e angle other than zero. 1. W ith vehicle on a level surface, determ ine fram e angle (w hether up or down in rear) with the use of a bubble protractor or inclinometer. Record this m easurem ent (See Figure 4). 2. M easure dimension "A " (See Figure 4). 3. Check and record specifications for caster under that column related to dimension " A " as measured in step 2. A norm al shim pack will leave a t least two (2) threads of the bolt exposed beyond the nut. If two (2) threads cannot be obtained, check for dam aged control arm s and related parts. The difference between front and rear shim packs must not exceed 7.62mm (.30 inches). Front shim pack must be at least 2.54m m (.10 inches). 4. Using one of the following rules, add or subtract fram e angle found in step 1 to or from specification found in step 3. a. A dow n-in-rear fram e angle must be added to a positive caster specification. b. An up-in-rear fram e angle m ust be subtracted from a positive caster specification. c. A dow n-in-rear fram e angle must be subtracted from a negative caster specification. d. An u p -in -rear fram e angle m ust be added to a negative caster specification. Access to Shim Packs G10-20 Models, CIO Models with 3/4" Nut: W ith vehicle on front end rack, jack at fram e and raise the wheel off the ground. This will allow the upper control arm to pivot down far enough to use a socket on the nuts and perm it shim removal. 3A-3 Vehicle caster specification should be adjusted to answer arrived at in step 4. Camber G30 Models, C20 and 30 Models with 7 /8 " Nut: Remove the upper control arm bum per; then follow the sam e procedure as above. R einstall the upper control arm bum per when alignm ent is completed. 1. D eterm ine the cam ber angle from the alignm ent equipment. 2. Add or subtract shims from both the front and rear bolts to affect a change. PIVOT SHAFT OUTBOARD OF FRAME CASTER CAMBER FORWARD Fig. 3A-2--Caster - Camber Adjustment LIG H T T R U C K SE RV IC E M AN U AL 3A-4 FRONT ALIGNMENT Toe-In "B ” IS LESS THAN “ A ” W H E N WHEELS TOE-IN 1. D eterm ine the wheel toe-in from the alignm ent equipment. 2. Change the length of both tie rod sleeves to affect a toe change. Toe-in can be increased or decreased by changing the length of the tie rods. A threaded sleeve is provided for this purpose. W hen the tie rods are mounted ahead of the steering knuckle they m ust be decreased in length in order to increase toe-in. W hen the tie rods are mounted behind the steering knuckle they m ust be lengthened in order to increase toe-in. See Section 3B for proper tie rod clam p orientation and positioning. Fig. 3A-3--Toe-ln Adjustment CROSSMEMBER Fig. 3A-4-Determining Caster LIG H T T R U C K SERVIC E M A N U A L FRONT ALIGNMENT 3A-5 SPECIFICATIONS WHEEL ALIGNMENT SPECIFICATIONS CASTER D IM E N S IO N " A " MODELS 2 1/2" 2% (mm) 6 3 .5 69 .8 C10 2.4° 2.1° 1.8° 1.5° 1.2° 1.0° 0.7° 0.5° 0.2° 0.1° 0.3° C20, 30 1.5° 1.2° 0.9° 0.6° 0.3° 0.1° 0° -0.1° -0.7° -1.0° -1.2° " 3" 3 %" 3 1/2" 3% 76.2 82.5 89.0 95.2 K10,20,30 (8°) " 4” 474" 4 1/2" 4% " 5" 102.0 107.9 114.3 121.6 127.0 ( N O A D J U S T M E :N T P R O V I S O N ) r / 2" 1% " 2" 21/4" 21/2" 2%" 3" 3% " 3 1/2" 3% " 4" (mm) 38 .0 44 .4 51.0 57.1 63 .5 69.8 76 .2 82.5 89.0 95.2 102.0 107.9 G10, 20 3.5° 2.8C 3.3° 3.1° 2:2° 2.9° 2.7° 1.6° 2.4° 2.2C 2.1° 1.9° 1.0° .7° .5° 2 1/2" 2% G30 (mm) 63 .5 P10 2.3° (mm) *P20, 30 2.5° 474" 1.9C .2° 4% 4% " 1.8° 0° 5" 3" 3 1/4" 3 1/2" 3 3/4" 4" 69.8 76 .2 82.5 89.6 95.2 102.0 107.9 114.3 120.6 127.0 2.0° 1.7° 1.5° 1.2° 0.9° 0.6° 0.4° " 4 1/2" 0.1° 2" 2 1/4" 21/2" 2 %" 3" 3V4" 3 1/2" 3 3/4" 4 " 51.0 57.1 63 .5 6 9 .8 76.2 82.5 89.0 95.2 2.9° 2.6° 2.3° 2.0° 1.7° 1.4° 1.2° 0.9° " -0.1° 4 1/4" 1.6° -0.2° -0 .3 * 41/2" 4% " 102.0 107.9 114.3 120.6 0.6° 0.4° 0.2° 0.1° * A D D .3° W IT H J B 8 O R J F 9 S U B T R A C T .4° W IT H R 0 5 2% (mm) 4 1/2" 3" 374" 3 1/2" 3% " 4" 63 .5 69.8 76.2 82.5 89.0 9 5.2 102.0 107.9 114.3 120.6 127.0 5.5° 5.3° 5.0° 4.7° 4.4° 4.1° MOTOR HOME (32) 21/2" " 4 1/4” 3.8° 3.6° 3.3° 4% " 3.1° 5" 2.9° C A M BER MODEL .2° C 10, 20, 30 1.0° ( N O A D J U S T M E N T P R O V I S I O N ) K 10, 20 K30 G 1 0 ,20 G30 P10, 20, 30 .5° (N O A D J U S T M E N T P R O V I S I O N ) .5° .2° .2° .2° M O T O R HO M E (32) A L IG N M E N T T O L E R A N C E S Warranty Repair Checking Caster C am ber T o e -In ± 1° ± 0.7° ± 1 / 8 "(3 .2 m m ) T O E -IN Periodic M otor C10, C20, C30 K10, K20, K 30 3 /1 6 " Vehicle Inspection G10, G20, G 30 3 /1 6 " (4.7 m m ) P10, P20, P30 3 /1 6 " (4.7 m m ) ± 0.5° ± 2° M O T O R HO M E ± 0.5° ± 1.5° 5 /1 6 " (7.9 m m ) Resetting Target P30 (32) 3 /1 6 " (4.7 m m ) ± 1 /1 6 "(1 .6 m m ) ± 3 / 8 "(9 . 5 m m ) Specifications L IG H T T R U C K SE RV IC E M A N U A L STEERING LINKAGE 3B1-1 SECTION 3B1 STEERING LINKAGE T he following notice applies to one or more steps in the assembly procedure of components in this portion of the m anual as indicated at appropriate locations by the terminology "See N otice on page 1 of this Section ". N O TICE: These fasteners are im portant attaching parts in th a t they could affect the perform ance of vital components and systems, an d /o r could result in m ajor repair expense. They must be replaced with one of the same part num ber or with an equivalent part if replacem ent becomes necessary. Do not use a replacem ent part of lesser quality or substitute design. Torque values m ust be used as specified during reassembly to assure proper retention of these parts. For prevailing torque nut(s) and bolt(s), refer to the " Reuse of Prevailing Torque N u t(s) and B olt(s)" chart in Section 10. CONTENTS G eneral D escription...................................................................................... 3B1-1 D iagnosis...........................................................................................................3B1-1 M aintenance and A d ju stm en ts...................................................................3B1-4 On-V ehicle S erv ice....................................................................................... .3B1-6 Tie R o d s...................................................................................................... .3B1-6 Relay R o d ....................................................................................................3B1-8 Idler A r m .....................................................................................................3B1-8 Pitm an A r m ............................................................................................... .3B1-9 Steering Connecting R o d ....................................................................... .3B1-9 GENERAL DESCRIPTION The steering linkage is located forward of the front crossmember. Refer to Fig. 3B1-1, for a typical system. Steering effort is transm itted to left and right hand adjusta­ ble tie rods through a relay rod. T he relay rod is connected to an idler arm on the right and to the pitm an arm on the left. DIAGNOSIS Reference should be m ade to the correct method of disassembly, repair, adjustm ent and reassembly. Dam aged, broken or deformed parts must be replaced with the correct replacem ent. L IG H T TR U C K SERVICE M A N U A L 3B1-2 STEERING LINKAGE CO N D ITIO N POSSIBLE C A U SE CORRECTIO N Front wheel bearings loosely adjusted. Adjust bearings to obtain proper end play. Worn steering shaft couplings. Replace part. Worn upper ball joints. Check and replace if necessary. Steering wheel loose on shaft, loose pitman arm, tie rods, steering arms or steering linkage ball studs. Tighten to specified torque, or replace if necessary. Steering gear thrust bearings loosely adjusted. Adjust preload to specification. Excessive over-center lash in steering gear. Adjust preload to specification. Worn intermediate rod or tie rod sockets. Replace worn part. Excessive looseness in tie rod or intermediate rod pivots, or excessive vertical lash in idler support. Seal damage and leakage resulting in loss of lubricant, corrosion and excessive wear. Replace damaged parts as necessary. Properly position upon reassembly. Excessive vertical lash in idler arm (P Series Motorhome) Excessive end play in support assembly. Adjust end play. Excessive Play or Looseness in Steering System. Fig. 3Bl-2--Steering Linkage Diagnosis Chart A LIG H T T R U C K SERVICE M A N U A L STEERING LINKAGE CONDITIO N Hard Steering - Excessive Effort Required at Steering Wheel. Poor Returnability. PO SSIBLE C A U SE 3B1-3 CO RRECTIO N Low or uneven tire pressure. Inflate to specified pressures. Steering linkage or bolt joints need lubrication. Lube with specified lubricant. Tight or frozen intermediate rod, tie rod or idler socket. Lube replace or reposition as necessary. Steering gear to column misalignment. Align column. Steering gear adjusted too tightly. Adjust over-center and thrust bearing preload to specification. Front wheel alignment incorrect, (manual gear) Check alignment and correct as necessary. Steering linkage or ball joints need lubrication. Lube with specified lubricant. Steering gear adjusted too tightly. Adjust over-center and thrust bearing preload to specifications. Steering gear to column misalignment. Align column. Front wheel alignment incorrect. (Caster) Check alignment and correct as necessary. Fig. 3Bl-3--Steering Linkage Diagnosis Chart B LIG H T T R U C K SERVICE M A N U A L 3B1-4 STEERING LINKAGE MAINTENANCE AND ADJUSTMENTS LUBRICATION K-SERIES LUBRICATION OF STEERING LINKAGE The steering linkage under norm al conditions should be lubricated with any w ater resistant EP type chassis lubri­ cant every 7,500 miles (12 000 km ) or six m onths, whichever occurs first. L ubricate every 3,000 miles (4 800 km) or two months whichever occurs first when operating in dusty or m uddy conditions or if th e vehicle is used "o ff-ro a d ". Lubrication points and additional inform ation on the chassis lubricant recom m ended can be found in Section 0 -G e n e ra l Inform ation and Lubrication. STEERING DAMPER CHECK E R IN G D A M P E R S T E E R IN G D A M P E R (Fig. 3B1-4) This type of steering dam per is nonadjustable, nonrefillable and is not repairable. A t each lubrication interval m ake check # 1 and # 2 on the steering dam per system. 1. Inspecting Damper Mountings: C heck th e dam per attachm ents to be sure they are properly and securely installed. (T ig h ten , if loose). R eplace th e d am per assembly if the rubber bushings are badly worn. 2. Inspecting Damper For Leaks: Inspect the dam per for evidence of fluid leakage. A light film of fluid is perm issible on the body of the dam per near the shaft seal. A dripping d am per should be replaced. If a Funtional or Noise C om plaint is R eported, M ake the Following Inspections: 3. Inspecting Damper For Noise: Disconnect the fram e or axle end of the dam per. Extend and compress the dam per using as much travel as possible. The dam per action should be smooth throughout each stroke. 4. Inspecting Damper For Functioning: W hile checking the dam per in step (3) above, observe the operation of LIG H T T R U C K SERVICE M A N U A L MOTOR HOME Fig. 3Bl-4--Steering Dampers the dam per for fluid leakage, effort and lag. Items from this check th at require dam per replacem ent are: A.Any fluid leakage during this check. B. Seizing or binding condition during travel of damper. C.A skip or lag at reversal near m id-stroke of dam per. 5. Reinstall Disconnected End of Damper Using Proper Torque. STEERING LINKAGE 3B1-5 RELAY ROD IDLER ARM ASSEMBLY TIE ROD ASSEMBLY l All clamps must be be tw ee n & clear of dimples before torquing nut. [ a ] [c a u t i o n KNUCKLE STEERING GEAR |~B~| Exposed socket thread length must be equal within ± . 0 6 at each end of a d ­ justing sleeve on L.H. & R.H. tie rod asm PITMAN ARM | C | All bolts must be installed in directions shown ADJUSTABLE CONNECTING ROD STEERING ARM IDLER ARM ASSEMBLY RELAY ROD TIE ROD ASSEMBLY STEERING GEAR ^ ASSEMBLY PITMAN ARM STEERING GEAR KNUCKLE STEERING ARM G-SERIES ^ PITMAN ARM X K-SERIES CONNECTING, ROD SUPPORT ASSEMBLY SUPPORT PITMAN ARM ,LEFT IDLER ARM RELAY ROD IDLER ARM ASSEMBLY GEAR MOUNTING BRACKET STEERING GEAR PITMAN ARM KNUCKLE TIE ROCr x ASSEMBLY P-SERIES Fig. 3B1-5--Steering Linkage LIG H T T R U C K SERVICE M A N U A L 3B1-6 STEERING LINKAGE ON-VEHICLE SERVICE NOTICE: See N O T IC E on page 1 of this section regarding all fasteners referred to in servicing steering linkage components. TIE RODS Removal 1. Raise vehicle on hoist. 2. Remove nuts from ball studs. The inner tie rod ends use crim p nuts, while the outer ends use castellated nuts and cotter pins. 3. To remove outer ball stud, tap on steering arm at tie rod end with a ham m er while using a heavy ham m er or sim ilar tool as a backing (Fig. 3 B 1-7). 4. Remove inner ball stud from relay rod using same procedure as described in Step 3. 5. To remove tie rod ends from tie rod, loosen clam p bolts and unscrew end assemblies. Fig. 3B1 -7—Ball Stud Removal-Typical Installation NOTICE: See the N O T IC E on page 1 of this section regarding the fasteners referred to in steps 4 and 6. Tie rod adjuster com ponents often become rusted in service. In such cases, it is recom m ended th at if the torque required to remove the nut from the bolt after breakaw ay exceed 7 pounds, discard the nuts and bolts. Apply penetrat­ ing oil between the clam p and tube and rotate the clamps until they move freely. Install new bolts and nuts having the same part num ber to assure proper clam ping at the specified nut torque. PRODUCTION NUT IMPORTANT WHENEVER ANY OF THE CRIMP NUTS OR STUDS AT THE (5) LOCATIONS SHOWN ARE LOOSENED OR REMOVED, THE FOLLOWING STEPS MUST BE TAKEN: A. WHEN RE-ATTACHING ANY TWO COMPONENTS BY MEANS OF A BALL STUD, CAREFULLY POSITION THE TWO PARTS. THEN IN STALL A FREE-SPINNING NUT, AND DRAW THE ITEMS TOGETHER TO SEAT THE TAPER, TORQUE NUT TO 54 N m (40 FT-LBS), THEN REMOVE NUT. B. THEN USE A TORQUE PREVAILING SERVICE REPLACEMENT NUT (#351249) AND TORQUE TO 90 N-m (66 FT-LBS), Fig. 3Bl-6--Typical Crimp Nut Locations L IG H T T R U C K SERVICE M A N U A L STEERING LINKAGE NOTE S lo t in adjuster sleeve m ust n o t be w itn in th is area o f cla m p jaws. C A U TIO N Clam ps m ust be between & clear o f d im ples before to rq u in g n u t. T IE ROD A D JU S T E R SLEEVE SLO T REARW ARDR O T A T IO N NOTE Locate clam ps w itn in to le ra n ce show n. VIEW 3B1-7 A RELAY O UTER S T E E R IN G K N U C K L E NOTE Equal w ith in th re e threads, m ust be visib le at inner and o u te r ends o f ad ju ster sleeve when assembled to steering k n u ckle . NOTE Locate clam ps w itn in to le ra n ce shown. •TIG H T NOTE S lo t in a djuster sleeve m ust n o t be w ith in th is area o f cla m p jaws. H O R IZ O N T A L L IN E A .005 M IN . G AP C A UTIO N C lam p ends m ay to u c h when nuts are to rq u e d to sp e cifica tio ns, b u t gap adjacent to ad ju ster sleeve m ust n o t be less th a n m in im u m dim ension show n. VIEW B C,K & P A D JU S TE R SLEEVE SLO T REARW ARD R O T A T IO N V IEW A C A UTIO N C lam p ends m ay to u c h when nuts are to rq u e d to s p e cifica tio n s, b u t gap adjacent to a d ju ster sleeve m ust n o t be less th a n m in im u m d im en sio n show n. VIEW B Fig. 3Bl-8--Tie Rod Clamp Relationship As a guide to correct orientation of the inner tie rod end relative to the outer tie rod end, rotate both ends to the extrem es of travel in the sam e direction before clamping. The position of each tie rod end m ust be m aintained as the clam ps are tightened to ensure free movement of each joint. R eturn the rod assembly to midposition of its travel. This should result in the inner and outer ball studs being retained in a parallel relationship with the interm ediate (relay) rod and steering knuckle (arm ) respectively. T he following procedure should be used when installing tie rods. 5. A djust toe-in as described in Section 3A. Before tightening the tie rod adjusting sleeve clam p bolts, be sure th at the following conditions have been met: a. The sleeve clam ps m ust be positioned between the locating dimples at either end of the sleeve. b. The clam ps m ust be positioned within the angular travel indicated in Figure 3B1-8. 1. If the tie rod ends were removed, lubricate the tie rod threads with EP Chassis lube and install ends on tie rod m aking sure both ends are threaded an equal distance from the tie rod. 2. M ake sure th at threads on ball studs and in ball stud nuts are clean and smooth. If threads are not clean and smooth, ball studs may turn in tie rod ends when attem pting to tighten nut. Check condition of ball stud seals; replace if necessary. Tool J-24434 may be used to install ball stud seals. 3. Install ball studs in steering arm s and relay rod. F o r the inner tie rod ends, use a free-spinning % - 1 8 nut to seat the ta p e rs, p e r Fig. 3 B 1-6. 4. A t th e ou ter tie rod ends, install a ball stud n u t, tighten to 70 N*m (50 lb. ft.), and install new c o tter pins. L u b ricate tie rod ends. Fig. 3B1 -9—Tie Rod Inspection LIG H T TR U C K SERVICE M A N U A L 3B1-8 STEERING LINKAGE c. The relationship of the clam p slot with the slit in the sleeve should be m aintained as shown in Figure 3B18. d. R otate both inner and outer tie rod housing rearw ard to the lim it of ball jo in t travel before tightening clam ps. Tighten clam ps to specifications. R eturn tie rod assem bly to the center of travel. e. All procedures for alignm ent, adjustm ent and assem ­ bly of tie rods applies to each side. f. Check each assem bly to be sure th at a total travel of at least 35° can be obtained using a bubble protractor and a pair of vise grips (Fig. 3B1-9). Inspection To ensure proper installation, it is necessary to perform the following inspection after any change of toe setting or removal of any ball stud: 1. Check the total rotation of the tie rod assembly using the following procedure: a. L ubricate inner and outer tie rod ends. b. A ttach vise grip pliers to the outer tie rod end. c. R otate outer tie rod end counterclockwise (up) to m axim um position. A ttach bevel protractor as shown in Figure 3B1-9. C enter protractor bubble indicator and record reading. d. R otate tie rod end clockwise (down) to m axim um position. C e n te r p ro tra c to r bubble in d icato r and record reading. e. Compare protractor readings obtained in Steps c and d. Total rotation o f tie rod assem bly should measure at least 35°. f. If rotation is less th an 35°, loosen one tiS rod sleeve clam p and rotate both tie rod ends to their m axim um lim it both ends must be rotated in the same direction. g. Tighten tie rod clam p and again rotate both ends to their m axim um limits, repeating Steps c and d. This recheck of total rotation will result in a m inim um of 35° travel. h. A fter obtaining the correct am ount of rotation (35° or g reater), position the outer tie rod end approx­ im ately m idway in this travel. Installation NOTICE: See the N O T IC E on page 1 of this section regarding the fasteners referred to in steps 2 and 3. 1. M ake sure th at threads on the ball studs and in the ball stud nuts are clean and smooth. If threads are not clean and sm ooth, ball studs m ay tu rn in sockets when attem pting to tighten nut. Check condition of ball stud seals; replace if necessary. 2. Install the relay rod to the idler arm and pitm an arm ball studs, m aking certain th e seals are in place. U se a free-spinning nut to seat the ta p ers, p er Fig. 3 B 1 -6 . Install the tie rods to the relay rod as previously described under "T ie Rod- In stallatio n ". L ubricate the tie rod ends. 4. Lower the vehicle to the floor. 5. A djust toe-in (see Section 3A) and align steering wheel as described previously in Section 3 B 4 under "S teering W heel A lignm ent and High Point C en tering". 3. IDLER ARM (EXCEPT P SERIES MOTORHOME) Use of the proper diagnosis and checking procedure is essential to prevent needless replacem ent of good idler arms. 1. Raise the vehicle in such a m anner as to allow the front wheels to rotate freely and the steering mechanism freedom to turn. Position the wheels in a straight ahead position. 2. Using a push pull type spring scale located as near the relay rod end of the idler arm as possible, exert a 25 lb. force upward and then downward while noticing the total distance the end of the arm moves. This distance should not exceed ± 1 /8 inch for a total acceptable movement of 1/4 inch (Figure 3B1-10). It is necessary to ensure th at the correct load is applied to the arm since it will move more when higher loads are applied. If rotating checks, outlined above, reveal a rough or lumpy feel, the inner or outer tie rod end assembly m ay have excessive w ear and should be replaced. If all of the above m entioned conditions are m et, proper tie rod installation is assured. RELAY ROD Removal 1. Raise vehicle on hoist. 2. Remove inner ends of the tie rods from relay rod as described under "T ie R od-R em oval". 3. Remove the nuts from the pitm an and idler arm ball studs a t the relay rod. 4. Remove the relay rod from the pitm an and idler arm s by tapping on the relay rod ball stud bosses with a ham m er, while using a heavy ham m er as a backing (Fig. 3B1-7). 5. Remove the relay rod from the vehicle. LIG H T T R U C K SERVICE M A N U A L Fig. 3B1-10--Checking Idler Movement, Typical STEERING LINKAGE It is also necessary th a t a scale or ruler be rested against the fram e and used to determ ine the am ount of movement since observers tend to over-estim ate the actual movement when a scale is not used. The idler arm should always be replaced if it fails this test. Jerking the right front wheel and tire assembly back and forth, thus causing an up and down movement in the idler arm is not an acceptable m ethod of checking since there is no control on the am ount of force being applied. C aution should be used in assum ing shimmy com­ plaints are caused by loose idler arm s. Before suspecting suspension or steering com ponents, techn icians should elim in ate shim m y excitation facto rs, such as dynam ic im balance, run-out or force variation of wheel and tire assem blies and road surface irregularities. Removal 1. Raise vehicle on a hoist. 2. Remove the nut from ball stud at the relay rod. Remove the ball stud from the relay rod by tapping on the relay rod boss with a ham m er, while using a heavy ham m er as a backing (Fig. 3B1-7). 3. Remove the idler arm to fram e bolt and remove the idler arm assembly. Installation NOTICE: See the N O T IC E on page 1 of this section regarding the fasteners referred to in steps 1 and 3. 1. Position the idler arm on the fram e and install the m ounting bolts (special plain w ashers under bolt heads); torque the nuts to specifications. 2. M ake sure th at the threads on the ball stud and in the ball stud nut are clean and smooth. If threads are not clean and smooth, ball stud m ay turn in the socket when attem pting to tighten nut. Check condition of ball stud seal; replace if necessary. 3. Install th e idler arm ball stud in th e relay rod, making certain the seal is positioned properly. U se a %-18 free-spinning nut to seat th e tap ers, p er Fig. 3B1-6. 4. Lower the vehicle to the floor. IDLER ARM — P SERIES MOTORHOME T he fram e m ounted idler su p p o rt assem bly is adjusta­ ble for su p p o rt shaft end play. C h eck for idler arm m ove­ m ent at the relay rod end as indicated above. If the m ove­ m ent at the end o f the arm ex ceed s ± 1/16 inch (1/8 inch total m ovem ent), readjust the support shaft end-play as follows: 1. L o o sen the su p p o rt assem bly ja m nut. 2. Tighten the adjusting plug to m etal-to-m etal contact. 3. B ack off the adjusting plug Vs o f a turn (Vi of a flat on the square nut, o r 45°). 4. R etorque th e ja m nut to 25-35 ft. lb s., while taking care th at the adjusting plug does not rotate. PITMAN ARM Removal 1. Raise vehicle on hoist. 2. Remove nut from pitm an arm ball stud. 3. Remove pitm an arm or relay rod from ball stud by 3B1-9 tapping on side of rod or arm (in which the stud mounts) with a ham m er while using a heavy ham m er or sim ilar tool as a backing. Pull on linkage to remove from stud. 4. Remove pitm an arm nut from pitm an shaft or clam p bolt from pitm an arm , and m ark relation of arm position to shaft. 5. Remove pitm an arm , using Tool J-6632 or J-5504. Installation NOTICE: See the N O T IC E on page 1 of this section regarding the fasteners referred to in steps 3 and 4. 1. Install pitm an arm on pitm an shaft, lining up the marks made upon removal. NOTICE: If a clam p type pitm an arm is used, spread the pitm an arm ju st enough, with a wedge, to slip arm onto pitm an shaft. Do not spread pitm an arm more than required to slip over pitm an shaft with hand pressure. Do not ham m er or dam age to steering gear may result. Be sure to install the hardened steel washer before installing the nut. 2. M ake sure th a t threads on ball studs and in ball stud nuts are clean and smooth. If threads are not clean and smooth, ball studs may turn in sockets when attem pting to tighten nut. C heck condition of ball stud seals; replace if necessary. 3. Install pitm an shaft nut or pitm an arm clam p bolt and torque to specifications. 4. Position ball stud onto pitm an arm or relay rod. U se a %-18 free-spinning nut to seat the tap ers, p er Fig. 3B1-6. Lubricate ball studs. Lower the vehicle to the floor. STEERING CONNECTING ROD (K MODELS ONLY) Removal 1. Remove cotter pins from ball studs, and then remove the castellated nuts. 2. Remove ball studs from steering arm and pitm an arm boss with a heavy ham m er and striking other side of boss with lighter ham m er (sim ilar to method shown in (Fig. 3B1-7). Installation NOTICE: See the N O T IC E on page 1 of this section regarding the fasteners referred to in step 3. 1. M ake sure th a t threads on ball studs and in ball stud nuts are clean and smooth. If threads are not clean and smooth, ball studs may turn in connecting rod when attem pting to tighten nut. Check condition of ball stud seals-replace if necessary. 2. Install ball studs in steering arm and pitm an arm . (Be sure to install the long end of the connecting rod assembly to the pitm an arm , as shown in Fig. 3B1-5). 3. Install ball stud nuts and torque to specifications. Never back off nut to align cotter pin, always tighten nut to next slot th a t lines up with hole in stud. 4. Install cotter pins and lubricate ball studs. For proper alignm ent and orientation of connecting rod clam ps see Figure 3B 1-11. LIG H T T R U C K SERVICE M A N U A L 3B1-10 STEERING LINKAGE SPECIFICATIONS AND SPECIAL TOOLS R efer to Specifications and Special Tools at end of Section 3B4. CAUTION: ENDS OF ADJUSTABLE TIE ROD MUST BE HELD IN CORRECT RELATIONSHIP TO EACH OTHER AFTER ADJUSTMENT WITHIN + 2°. CAUTION: CLAMPS MUST BE BETWEEN AND CLEAR OF DIMPLES BEFORE T0RQUIN6 NUT. NOTE: STEERING CONNECTING ROD MUST BE INSTALLED WITH LONG END FORWARD. STEERING GEAR ASSEMBLY .10 CLAMP V IE W A NOTE: SLOT O F -----ADJUSTER TUBE MAY BE IN ANY POSITION ON ARC SHOWN BUT NOT CLOSER THAN .10 TO THE EDGE OF CLAMP JAWS OR BETWEEN THEM. Fig. 3B1-11--Adjustable Connecting Rod Assembly-K Series LIG H T T R U C K SERVICE M A N U A L ADJUSTER TUBE MANUAL STEERING GEAR 3B2-1 SECTION 3B2 MANUAL STEERING GEAR The following notice applies to one or more steps in the assembly procedure of com ponents in this portion of the m anual as indicated at appropriate locations by the terminology "See N otice on page 1 of this S ection". N O TICE: This fastener is an im portant attaching part in th at it could affect the perform ance of vital components and systems, an d /o r could result in m ajor repair expense. It must be replaced with one of the same part num ber or with an equivalent part if replacem ent becomes necessary. Do not use a replacem ent part of lesser quality or substitute design. Torque values m ust be used as specified during reassem bly to assure proper retention of this part. CONTENTS G eneral D escription.....:.................................................................................3B2-1 D iagnosis.................................. ........................................................................3B2-1 M aintenance and A d ju stm e n ts................................................................. .3B2-4 On-V ehicle S erv ice....................................................................................... .3B2-5 M anual Steering G e a r............................................................................. .3B2-5 Pitm an S haft S eal......................................................................................3B2-6 S pecifications.................................................................................................. .3B2-7 Special T ools....................................................................................................3B2-7 GENERAL DESCRIPTION The steering gear is of the recirculating ball type. This gear provides for ease of handling by transm itting forces from the w orm shaft to the pitm an shaft through the use of ball bearings. DIAGNOSIS This section contains diagnostic inform ation to help locate the cause of steering problems that may be related to the m anual steering gear. Reference should be m ade to the correct m ethod of disassem bly, repair, a d ju stm en t and reassembly. D am aged, broken or deformed parts m ust be replaced with the correct replacem ent. Fig. 3B2-1--Manual Steering Gear LIG H T T R U C K SERVICE M A N U A L 3B2-2 MANUAL STEERING GEAR C O N D IT IO N P O S S IB L E C A U SE Rattle or Chuck in Steering Gear. Insufficient or improper lubricant in steering gear. Add lube specified. Pitman arm loose on shaft or steering gear mounting bolt loose. Tighten to specified torque. Loose or worn steering shaft bearing. Replace steering shaft bearing. Excessive over-center lash or worm thrust bearings adjusted too loose. Adjust steering gear to specified preloads. C O R R E C T IO N NOTE: On turns a slight rattle may occur, due to the increased lash between ball nut and pitman shaft as gear moves off the center of “high point” position. This is normal and lash must not be reduced to eliminate this slight rattle. Poor Returnability Steering column misaligned. Align column. Insufficient or improper lubricant in steering gear or front suspension. Lubricate as specified. Steering gear adjusted too tight. Adjust over-center and thrust bearing preload to specifications. Front wheel alignment incorrect (Caster) Adjust to specifications. 1 Fig. 3B2-2--Manual Gear Diagnosis Chart A LIG H T T R U C K SERVICE M A N U A L MANUAL STEERING GEAR C O N D IT IO N Excessive Play or Looseness in Steering System. Hard Steering Excessive Effort Required at Steering Wheel P O S S IB L E C A U S E 3B2-3 C O R R E C T IO N Front wheel bearings loosely adjusted. Adjust to obtain proper end play. Worn upper ball joints. Check and replace ball joints if necessary. Steering wheel loose on shaft, loose pitman arm, tie rods, steering arms or steering linkage ball nuts. Tighten to specification, replace if worn or damaged. Excessive over-center lash. Adjust over-center preload to specifications. Worm thrust bearings loosely adjusted. Adjust worm thrust bearing preload to specifications. Low or uneven tire pressure. Inflate to specified pressures. Insufficient or improper lubricant in steering gear or front suspension. Lubricate as specified. Relubricate at specified intervals. Steering shaft flexible coupling misaligned. Align column and coupling. Steering gear adjusted too tight. Adjust over-center and thrust bearing preload to specifications. Front wheel alignment incorrect. (Manual Gear) Adjust to specifications. Fig. 3B2-3~Manual Gear Diagnosis Chart B LIG H T TR U C K SERVICE M A N U A L 3B2-4 MANUAL STEERING GEAR MAINTENANCE AND ADJUSTMENTS LUBRICATION OF MANUAL STEERING GEAR The m anual steering gear is factory-filled with steering gear lubricant. Seasonal change of this lubricant should not be perform ed and the housing should not be drained-no lubrication is required for the life of the steering gear. According to the intervals listed in Section OB, the m anual gear should be inspected for seal leakage (actual solid grease - not just oily film). If a seal is replaced or the gear is overhauled, the gear housing should be refilled with 1051052 (13 oz. container) Steering Gear Lubricant which meets GM Specification GM 4673M , or its equivalent. NOTICE: Do not use EP Chassis Lube, which meets G M Specification G M 6 0 3 1M, to lubricate the gear DO NOT OVER-FILL the gear housing, or dam age may occur to the gear. ADJUSTMENT OF MANUAL STEERING GEAR NOTICE: See N o tice on page one of this section regarding the fasteners referred to in steps 9d and 10. 6. Turn the steering wheel gently in one direction until stopped by the gear; then turn back one-half turn. NOTICE: Do not turn the steering wheel hard against the stops when the steering linkage is disconnected from the gear as dam age to the ball guides could result. 7. M easure and record "bearing d rag " by applying a torque wrench with a socket on the steering wheel nut and rotating through a 90° arc (Fig. 3B2-6). Do not use a torque wrench having a m axim um torque reading of more than 50 inch pounds. 8. A djust " th ru s t bearing p relo ad " by tig htening the adjuster plug until the proper "th ru st loading preload" is obtained (See specifications section). W hen the proper preload has been obtained, tighten the adjuster plug locknut to specifications and recheck torque. If the gear feels "lum py" after adjustm ent, there is probably dam age in the bearings due to severe im pact or Before any adjustm ents are m ade to the steering gear attem pt to correct com plaints of loose or hard steering, or other wheel disturbances, a careful check should be m ade of front end alignm ent, shock absorbers, wheel balance and tire pressure for possible steering system problems. See Diagnosis earlier in this section. C orrect adjustm ent of steering gear is very im portant. W hile th e re are but two ad ju stm en ts to be m ade, the following procedure must be followed step-by-step in the order given. 1. Disconnect the b attery ground cable. 2. Raise the vehicle. 3. Remove the pitm an arm nut. M ark the relationship of the pitm an arm to th e pitm an shaft. Rem ove the pitm an arm with Tool J-6632 or J-5504 as shown in Figure 3B2-4. 4. Loosen the steering gear adjuster plug locknut and back the adjuster plug off 1/4 turn (Fig. 3B2-5). 5. Remove the horn shroud or button cap. Fig. 3B2-4--Removing Pitman Arm LIG H T T R U C K SERVIC E M A N U A L Fig. 3B2-6--Checking Torque at Steering Wheel MANUAL STEERING GEAR improper adjustm ent; the gear m ust be disassembled and inspected for replacem ent of dam aged parts. 9. A djust "over-center preload" as follows: a. T urn the steering wheel gently from one stop all the way to the other carefully counting the total num ber of turns. T urn the wheel back exactly half-way, to center position. b. T urn the lash adjuster screw clockwise to take out all lash between the ball nut and pitm an shaft sector teeth and then tighten the locknut. c. C heck the torque at the steering wheel, taking the highest reading as the wheel is turned through center position. See Specifications for proper over-center preload. d. If necessary, loosen locknut and readjust lash ad ­ ju ster screw to obtain proper torque. Tighten the locknut to specifications and again check torque reading through center of travel. If m axim um speci­ fication is exceeded, turn lash adjuster screw coun­ terclockwise, then come up on adjustm ent by turning . the adjuster in a clockwise motion. 10. Reassem ble the pitm an arm to the pitm an shaft, lining up the m arks m ade during disassembly. Torque the pitm an shaft nut to specifications. If a clam p type pitm an arm is used, spread the pitm an arm ju st enough, with a wedge, to slip the arm onto the pitm an shaft. Do not spread the clam p more than required to slip over pitm an shaft with hand pressure. Do not ham m er the pitm an arm onto the pitm an shaft. Be sure to install the hardened steel washer before installing the nut. ON-VEHK STEERING GEAR Removal 1. S et the front wheels in s tra ig h t ahead position by driving vehicle a short distance on a flat surface. 3B2-5 11. Install the horn button cap or shroud and connect the battery ground cable. 12. Lower the vehicle to the floor. STEERING GEAR HIGH POINT CENTERING 1. Set front wheels in straight ahead position. This can be checked by driving vehicle a short distance on a flat surface to determ ine steering wheel position at which vehicle follows a straight path. 2. W ith front wheels set straight ahead, check position of m ark on w orm shaft designating steering gear high point. This m ark should be at the top side of the shaft at 12 o’clock position and lined up with the m ark in the coupling lower clamp. 3. On C, G and P series, if the gear has been moved off high point when setting wheel in stra ig h t ahead position, loosen adjusting sleeve clamps on both left and right hand tie rods. Then turn both sleeves an equal num ber of turns in the same direction to bring gear back on high point. Turning the sleeves an unequal num ber of turns or in different directions will disturb the toe-in setting of the wheels. 4. On K series, if the gear has been moved off' high point when setting wheels in straight ahead position, loosen adjusting sleeve clamps on the connecting rod. Then turn sleeve to bring gear back on high point. 5. R eadjust toe-in as outlined in Section 3A (if necessary). 6. Be sure to properly orient sleeves and clamps when fastening and torqueing clam ps to proper specifications. 1 SERVICE 2. Remove the flexible coupling to steering shaft flange bolts (C-K models) or the lower universal joint pinch bolt (P models). M ark the relationship of the universal yoke to the worm shaft. 3. M ark the relationship of the pitm an arm to the pitm an shaft. Remove the pitm an shaft nut or pitm an arm pinch bolt and then remove the pitm an arm from the pitm an shaft using Puller J-6632 (Fig. 3B2-9). L IG H T T R U C K SE RV IC E M A N U A L 3B2-6 MANUAL STEERING GEAR 4. Remove the steering gear to fram e bolts and remove the gear assembly. 5. C-K Models - Remove the flexible coupling pinch bolt and rem ove the coupling from the steering gear worm shaft. Installation NOTICE: See N O T IC E on page 1 o f this section regarding the fasteners referred to in steps la , lc, Id, le, 2b, 2c and 3. 1. C-K Models 3. Install the pitm an arm onto the pitm an shaft, lining up the m arks made at removal. Install the pitm an shaft nut or pitm an arm pinch bolt and torque to specifications. If a clam p type pitm an arm is used, spread the pitman arm just enough, with a wedge, to slip the arm onto the pitm an shaft. Do not spread the clam p more than required to slip over pitm an arm onto the pitm an shaft. Be sure to install the hardened steel washer before installing the nut. PITMAN SHAFT SEAL REPLACEMENT a. Install the flexible coupling onto the steering gear w orm shaft, aligning the flat in the coupling with the flat on the shaft. Push the coupling onto the shaft until the w orm shaft bottom s on the coupling rein­ forcem ent. In stall th e pinch bolt and torq u e to specifications. The coupling bolt m ust pass through the shaft undercut. b. Place the steering g ear in position, guiding the coupling bolt into the steering shaft flange. c. Install the steering gear to fram e bolts and torque to specifications. d. If flexible coupling alignm ent pin plastic spacers were used, m ake sure they are bottom ed on the pins, torque the flange bolt nuts to specifications and then remove the plastic spacers. e. If flexible coupling alignm ent pin plastic spacers were not used, center the pins in the slots in the steering shaft flange and then install and torque the flange bolt nuts to specifications. 2. P Models a. Place the steering g ear in position, guiding the w orm shaft into th e universal jo in t assem bly and lining up the m arks m ade at removal. If a new gear was installed, line up the m ark on the w orm shaft with the slit in the universal joint yoke. A faulty seal may be replaced without removal of steering gear from C, G and P trucks by removing pitm an arm as outlined under M aintenance and A djustm ents Steering G ear A djustm ents and proceed as follows: On K series vehicles remove the gear from the vehicle first. 1. R otate the steering wheel from stop to stop, counting the total num ber of turns. Then turn back exactly half­ way, placing the gear on center (the w orm shaft flat should be at the 12 o’clock position). 2. Remove the three self-locking bolts a tta ch in g side cover to the housing and lift the pitm an shaft and side cover assembly from the housing. 3. Pry the pitm an shaft seal from the gear housing using a screw driver and being careful not to dam age the housing bore. See Fig. 3B2-10. NOTICE: Inspect the lubricant in the gear for contam i­ nation If the lubricant is contam inated in any way, the gear m ust be removed from the vehicle and completely overhauled as outlined in the U nit R epair M anual, or dam age to the gear could result. b. Install the steering gear to fram e bolts and torque to specifications. 4. Coat the new pitm an shaft seal with Steering G ear Lubricant meeting GM Specification G M 4673M (or equivalent). Position the seal in the pitm an shaft bore and tap into position using a suitable size socket. c. Install the universal joint pinch bolt and torque to specification. The pinch bolt m ust pass through the shaft undercut. 5. Remove the lash adjuster lock nut. Remove the side cover from the pitm an shaft assembly by turning the lash adjuster screw clockwise. TOOL—J-5504 Fig. 3B2-9--Removing Pitman Arm-Typical LIG H T T R U C K SERVICE M A N U A L MANUAL STEERING GEAR 6. Place the pitm an shaft in the steering gear such th at the center tooth of the pitm an shaft sector enters the center tooth space of the ball nut. 7. Fill th e steering gear housing with S teerin g G ear L ubricant meeting G M Specification G M 4673M (or equivalent). 8. Install a new side cover gasket onto the gear housing. 9. Install the side cover onto the lash adjuster screw by reaching through the threaded hole in the side cover with a small screwdriver and turning the lash adjuster screw counter- clockwise until it bottom s and turns back in 1/4 turn. 3B2-7 10. Install the side cover bolts and torque to specifications. 11. Install the lash adjuster screw locknut, perform steerin gear adjustm ent and install the pitm an arm as outllined under " M aintenance and A djustm ents". On K series install the gear into the vehicle using previously outlined procedure. SPECIFICATIONS AND SPECIAL TOOLS Refer to Specifications and Special Tools at end of Section 3B4. L IG H T TR UC K SE RV IC E M AN U AL POWER STEERING SYSTEM 3B3-1 SECTION 3B3 POWER STEERING SYSTEM The following notice applies to one or more steps in the assembly procedure of com ponents in this portion of the m anual as indicated at appropriate locations by the term inology "See N otice on page 1 of this S ection". N O TICE: This fastener is an im portant attaching part in th at it could affect the perform ance of vital components and systems, an d /o r could result in m ajor repair expense. It m ust be replaced with one of the same part num ber or with an equivalent part if replacem ent becomes necessary. Do not use a replacem ent part of lesser quality or substitute design. Torque values m ust be used as specified during reassem bly to assure proper retention of this part. CONTENTS G eneral D escription..........................................................................................3B3-1 D iagnosis............................................................................................................ .3B3-2 M aintenance and A d ju stm e n ts.....................................................................3B3-10 On-V ehicle S erv ice.............................................................................. ............3B3-12 Power Steering G e a r ...................................................................................3B3-12 Power Steering P u m p ................................................................................ .3B3-13 Power Steering H oses................................................................................ .3B3-15 S p ecifications.................................................................................................... .3B3-15 Special T o o ls..................................................................................................... .3B3-15 GENERAL DESCRIPTION The steering gear is of the recirculating ball type. This gear provides for ease of handling by transm itting forces from the w orm shaft to the pitm an shaft through the use of ball bearings. Fig. 3B3-1--Power Steering System L IG H T T R U C K SE RV IC E M AN U AL 3B3-2 POWER STEERING SYSTEM POWER STEERING PUMP 1. DRIVE SHAFT 13. RING, Shaft Retainer 2 SEAL 14. VANE KIT, Rotor 3 SEAL, Reservoir "O " Ring 15. RING KIT, Pump Rotor 4. HOUSING ASSEM BLY 16. PLATE, Pressure 5 . SEAL 17. SPRING, Pressure Plate 6. PIN, Pump Ring Dowel 18. PLATE, Pump Housing End 7. PLATE Thrust 19. RING, End Plate Retaining 8 CAP Filler 20. SEAL. Reservoir 9 VALVE ASSEMBLY, Flow Control 21. RESERVOIR ASSEMBLY 10. SPRING, Flow Control 22. BOLT 11. SEAL 23. SEAL 12 ROTOR, Pump 24. FITTING, W Orifice Fig. 3B3-2 -- Pump and G ear Cross-Section DIAGNOSIS (FIGS. 3B3-3 THROUGH 3B3-8) System Checks Com plaints of faulty steering are frequently the result of problems other than the steering gear or pump. Those areas of the steering system which can be easily checked and quickly corrected w ithout disassem bly and overhaul of any major components should be attem pted first. M any factors affect power operation of the steering system, of which the most common are: 1. Fluid level and condition. 2. Drive belt tension. 3. Loose component mountings. 4. Loose pump pulley. Conditions such as hard or loose steering, road shock or vibrations are not always due to the steering gear or pump, but are often related instead to such factors low tire pressure and front end alignm ent. These factors should be checked and corrected before any ad justm ent or disassem bly of the power steering gear or pump is attem pted. LIG H T T R U C K SERVIC E M A N U A L These factors must be checked and corrected before making any further diagnosis of the steering system. The need for proper diagnosis cannot be over-emphasized. A fter the source of the problem has been found, determ ine the cause. For example, if the oil level in the reservoir is found to be low, refill and check the entire hydraulic system for oil leaks. Refilling the reservoir will not necessarily correct the problem. POWER STEERING SYSTEM CONDITION POSSIBLE CAUSE 3B3-3 CORRECTION S Y ST E M N O IS E There is some noise in all power steering systems. Common complaints are listed as follows: Pump noise-“chirp” . Loose belt. Adjust belt tension to specification. Belt squeal. Loose belt. Adjust belt tension to specification. Gear noise (“ hissing” sound) There is some noise in all power steer­ ing systems. One of the most common is a hissing sound most evident at standstill parking. There is no relation­ ship between this noise and perfor­ mance of the steering. “ Hiss” may be expected when steering wheel is at end of travel or when slowly turning at standstill. Do not replace valve unless “ hiss” is extremely objectionable. Slight “ hiss” is normal and in no way affects steer­ ing. A replacement valve will also exhi­ bit slight noise and is not always a cure for the objection, investigate clearance around flexible coupling rivets. Be sure steering shaft and gear are aligned so flexible coupling rotates in a Hat plane and is not distorted as shaft ro­ tates. Any metal-to-metal contacts through flexible coupling will transmit “hiss” into passenger compartment. Also, check for proper sealing between steering column and toe pan. Rattle. Pressure hose touching other parts of car. Adjust hose position. Loose pump pulley nut Replace nut, torque to specs. Pump vanes not installed properly. Install properly. Pump vanes sticking in rotor slots. Free up by removing burrs, varnish or dirt. Improper over-center adjustment Adjust to specifications. Gear noise (rattle or chuckle). NOTE: A slight rattle may occur on turns because of increased clearance off the “ high point” . This is normal and clearance must not be reduced below specified limits to eliminate this slight rattle. Loose pitman arm. Tighten to specifications Gear loose on frame. Check gear-to-frame mounting bolts. Tighten bolts to 70 foot-pounds. Rattle or chuckle. Steering linkage looseness. Check linkage pivot points for wear. Replace if necessary. Groan. Low oil level. Fill reservoir to proper level. Groan. Air in the oil. Poor pressure hose connection. Bleed system by operating steering from right to left full turn. Check connections, torque to specs. Growl. Excessive back pressure caused by hoses or steering gear, (restriction) Locate restriction and correct. Replace part if necessary. Fig. 3B3-3--Power Steering System Diagnosis Chart A LIG H T T R U C K SERVIC E M A N U A L 3B3-4 POWER STEERING SYSTEM CONDITION POSSIBLE CAUSE CORRECTION Scored pump pressure plates, thrust plate or rotor. Replace affected parts, flush system. Extreme wear of pump cam ring. Replace affected parts. Swish in pump Defective pump flow control valve Replace valve Whine in pump Pump shaft bearing scored. Replace housingand shaft, flush system Squawk in gear (not belt) D am per “ 0 ” ring on valve spool cut Replace “0 ” ring. Pump growl Note: Most noticeable at full wheel travel and stand still parking SY STE M O P E R A T IO N Excessive wheel kick-back or loose steering. Poor return of steering. Backlash in steering linkage. Adjust parts affected or replace worn parts. Air in system. Add oil to pump reservoir and bleed by operating steering. Check all connections. Excessive “over-center” lash. Adjust to specification. Loose thrust bearing preload adjust­ ment. Adjust to specification. Worn poppet valve (Gear) Replace poppet valve. Steering gear loose on frame. Tighten attaching bolts to 70 foot­ pounds. Steering gear flexible coupling too loose on shaft or rubber disc mounting screws loose. Tighten flange pinch bolts to 30 foot­ pounds, if serrations are not damaged. Tighten upper flange to coupling nuts to 20 foot-pounds. Steering linkage ball studs worn enough to be loose. Replace loose components. Front wheel bearings incorrectly ad­ justed or worn. Adjust bearings or replace with new parts as necessary. Tires under-inflated. Inflate to specified pressure. Lower coupling flange rubbing against steering gear adjuster plug. Loosen pinch bolt and assemble prop­ erly. Steering wheel rubbing against direc­ tional signal housing. Adjust steering jacket. Tight or frozen steering shaft bearings. Replace bearings. Steering linkage or ball joints binding. Replace affected parts. Steering gear to column misalignment. Align steering column. Tie rod pivots not centralized. Adjust tie rod ends as required to center pivots. Lack of lubricant in suspension ball joints and steering linkage Lubricate and relubricate at proper intervals Fig. 3B3-4--Power Steering System Diagnosis Chart B L IG H T T R U C K SERVICE M A N U A L POWER STEERING SYSTEM CONDITION Poor return of steering. (Cont’d.) * ■ Car leads to one side or the other. (Keep in mind road condition and wind. Test car on flat road going in both directions) POSSIBLE CAUSE 3B3-5 CORRECTION Steering gear adjustments over specifications. Check adjustment with pitman arm disconnected. Readjust if necessary. Sticky or plugged valve spool. Remove and clean or replace valve. Rubber spacer binding in shift tube. Make certain spacer is properly seated. Lubricate inside diameter with sili­ cone lubricant. Improper front suspension alignment. Check and adjust to specifications. Tight steering shaft bearings. Replace bearings. Front suspension misaligned Adjust to specifications. Steering shaft rubbing ID of shift tube. Align column. Unbalanced or badly worn steering gear valve. Replace valve. N O TE : If this is cause, steering effort will be very light in direction of lead and heavy in opposite direction. Steering wheel surges or jerks when turning with engine running especially during parking. Momentary increase in effort when turning wheel fast to right or left. Hard steering or lack of assist. Steering linkage not level. Adjust as required. Low oil level in pump. Check oil level, add as necessary. Loose pump belt. Adjust tension to specification. Sticky flow control valve. Inspect for varnish or damage, replace if necessary. Insufficient pump pressure. Check pump pressure. (See pump pressure test). Replace relief valve if defective. Steering linkage hitting engine oil pan at full turn. Correct clearance. Pump belt slipping. Tighten or replace belt. Low oil level in pump. Check oil level, add as necessary. High internal leakage. Check pump pressure (Test) High internal leakage. (Gear or pump) Check pump pressure test). Loose pump belt. Adjust belt tension to specification. Low oil level in reservoir. Fill to proper level. If excessively low, check all lines and joints for evidence of external leakage, torque to specs. pressure. (See pump Fig. 3B3-5--Power Steering Diagnosis Chart C L IG H T T R U C K SERVIC E M AN U AL 3B3-6 POWER STEERING SYSTEM POSSIBLE CAUSE CONDITION Hard Steering or lack of assist (Continued) Low oil pressure due to restriction in hoses: Low oil pressure due to steering gear: (See pump pressure test) CORRECTION Lack of lubricant in suspension or ball jo in ts. Lubricate, relubricate at proper intervals. Tires not properly inflated. Inflate to recommended pressure. Steering gear to column misalignment. Align steering column. Steering gear adjusted too tight. Test steering system for binding with front wheels off floor. Adjust as neces­ sary. Excessive friction in steering linkage. Check tie rod pivot points for exces­ sive friction. Replace the affected pivot. Lower coupling flange rnbbing against steering gear adjuster plug. Loosen pinch bolt and assemble properly. Sticky flow control valve. Replace or clean valve. Frame bent. Check frame for proper alignment or cracking. Repair or replace as neces­ sary. Front springs weak and sagging. Check standing height. Weak or sag­ ging springs should be replaced with new ones. Insufficient oil pressure. If above checks do not reveal cause of hard steering, diagnose hydraulic system to determine problem. Check for kinks in hoses. Remove kink. Foreign object stuck in hose. Remove hoses and remove restricting object or replace hose. Pressure loss in cylinder due to worn piston ring or scored housing bore. Remove gear from car for disassembly and inspection of ring and housing bore. Replace affected parts. Leakage at valve rings, valve body to worm seal. Remove gear from car for disassembly and replace seals. Loose fit of spool in valve body or leaky valve body. Replace valve. Damaged poppet valve. Replace valve. Fig. 3B3-6--Power Steering System Diagnosis Chart D L IG H T T R U C K SERVICE M A N U A L POWER STEERING SYSTEM POSSIBLE CAUSE CONDITION Low oil pump: pressure due to steering 3B3-7 CORRECTION Loose belt. Adjust tension to specification Low oil level. Fill reservoir to proper level. Air in the oil. Locate source of leak and correct. Bleed system. Defective hoses or steering gear. Correct as necessary. Flow control valve stuck or inopera­ tive. Remove burrs or dirt or replace. Loose screw in end of How control valve. Tighten. Cracked or broken thrust or pressure plate. Replace part. Pressure plate not flat against cam ring. Replace pressure plate. Extreme wear of cam ring. Replace parts, flush system Scored pressure plate, thrust plate or rotor. Replace parts. (If rotor, replace with rotating group kit), flush system Vanes not installed properly. Install properly. Radius edge to outside. Vanes sticking in rotor slots. Free-up b> removing burrs, varnish or dirt. Air in the fluid, and loss of fluid due to internal pump leakage causing overflow. Check for leak and correct. Bleed system. Extremely cold temperatures will cause system aeriation should the oil level be low. If oil level is correct and pump still foams, remove pump from vehicle and separate reservoir from housing. Check welsh plug and housing for cracks. If plug is loose or housing is cracked, replace housing. (See pump pressure test.) Note: Steering system external leakage Foaming rmlky power steering fluid, low level and possible low pressure. Fig. 3B3-7-Power Steering System Diagnosis Chart E LIG H T TR U C K SE RV IC E M AN U AL 3B3-8 POWER STEERING SYSTEM POWER STEERING SYSTEM EXTERNAL LEAKAGE G en eral Procedure 1. 2. 3. 4. 5. W ipe suspected area dry. Check for overfilled reservoir. Check for oil aeration and overflow. Check hose connections - tighten if necessary. Verify exact point of leakage. Exam ple:Torsion bar, stub shaft and adjuster seals are close together; exact leakage point could be confused. Example: The point oil drips from is not necessarily the leakage point - oil overflowing from reservoir for instance. 6. W hen service is required: a. Clean leakage area upon disassembly. b. Replace leaking seal. c. Check com ponent sealing surfaces for dam age. d. Reset bolt torque to specifications where required. Customer Descriptions Some of the custom er com plaints associated with the power steering system m ay be reported as: 1. O i l le a k a g e on g a r a g e floor. 2. Oil leaks visible on steering gear, pump, or anywhere else on the left side of engine com partm ent. 3. Growling noise especially when parking or when engine is cold. 4. Loss of power when parking. 5. Heavy steering effort. For the purpose of trouble shooting com plaints of this nature, assum e th at there is an external leak in the power steering system. Leakage Diagnosis (Fig. 3B3-8) This section is a guide, which will enable you to locate, identify, and repair leaks in the power steering system. It contains: A. D iagram of the com plete power steering system with the areas of potential leakage identified. B. Recom m ended procedure for locating external leakage in the vehicle. C. A reas of leakage to be checked, which can be serviced at once. D. P art replacem ent recom m endations. E. D iagram of the actual areas where leakage will be observed and the action recom m ended to repair this leakage. Leakage Check The purpose of the diagnostic procedure is to pin-point the location of the leak. The m ethod outlined in this m anual can be followed to locate the leak and repair it. In some cases you will be able to locate the leak easily. However, seepage type leaks m ay be more difficult to isolate. For seepage leaks, the following m ethod is recom m ended. L IG H T T R U C K SE RV IC E M A N U A L A. W ith the vehicle’s engine off, wipe the complete power steering system dry (g ear, pum p, hoses, and connections). B. Check oil level in p um p’s reservoir and ad ju st as directed in m aintenance section. C. S tart engine and turn steering wheel from stop to stop several times. Do not hold in corner for any length of time as this can dam age the power steering pump. It is easier if someone else operates the steering wheel while you search for the seepage. D. Find the exact area of leakage. E. Refer to the diagnostic chart to find the recommended method of repair. Quick Fixes The purpose of this section is to acquaint you with the types of leakage which can be repaired very easily. It contains inform ation on reservoir oil level, the hoses and the hose connections. An overfilled pump reservoir can be a cause for leakage complaint. The oil in the steering system expands as heated during norm al usage. If overfilled the excess is forced thhrough the breather cap hole and may be sprayed over the engine by air blast. O perate the engine and steering system until normal operating tem perature is obtained. Remove the reservoir cap and check the graduated level on the dipstick. Adjust the oil level as required. Seepage at the hose connections can be a cause for leakage com plaint and can be due to loose connection nuts. If leakage is observed at the hose connections, and the nut is not cross threaded, tighten the nuts at the gear to 30 foot pounds. The nut at the power steering pum p should be tig h t­ ened to 40 foot pounds. If tightening to this torque does not stop the leak, refer to the diagnostic chart. If either the return hose or the pressure hose leaks, replace the hose. Component Replacement Lip seals, which seal rotating shafts, require special treatm ent. This type of seal is used on the steering gear at the pitm an shaft, at the stud shaft, and on the drive shaft of the pump. W hen leakage occurs in one of these areas, always replace the seal(s), after inspecting and thoroughly cleaning the sealing surfaces. Replace the shaft only if very severe pitting is found. If the corrosion in the lip seal contact zone is slight, clean the surface of the shaft with crocus cloth. R eplace the sh aft only if the leakage cannot be stopped by smoothing with crocus cloth first. Housing or Cover Seepage - Both the power steering gear and pum p assem blies are leakage checked before shipm ent. However, occasionally oil seepage m ay occur from the gear or pump other than the seal areas. If this type of leakage is found, replace the leaking part. Fig. 3B3-8 has been prepared to show the potential areas of leakage. If leakage occurs in the zones shown, replace the part listed using the service m anual as a guide. POWER STEERING SYSTEM 3B3-9 GEAR A N D PUMP LEAK DIAGNOSIS ST A R T E N G IN E A N D TU RN S T E E R IN G WHEEL F R O M S T O P TO ST O P S E V E R A L T IM E S . DO NOT H O LD AT ST O P FO R A N Y LENGTH OF T IM E A S T H IS C A N D A M A G E THE PO W ER S T E E R IN G P U M P . 1. C H E C K O IL L E V E L IF L E A K A G E P E R S I S T S W IT H THE LEVEL C O R R E C T A N D THE C A P TIGHT. R E P L A C E C AP. 2. C R A C K E D O R BENT R E S E R V O IR . 3. R E P L A C E R E S E R V O IR " 0 " R IN G . 4. R E P L A C E FR O N T S E A L R E P L A C E R E S E R V O IR . M A K E C E R T A IN TH AT D R I V E SH A F T IS C LE A N A N D FREE OF P IT T IN G IN S E A L R ID E AREA. 5. T O RQ U E H O SE F IT T IN G NUT T 0 27 N-m (20 FT. L B S. I. IF 6. TO RQ UE F IT T IN G T 0 4 8 N-m (35 FT. L B S .). L E A K A G E P E R S IS T S . P E R S IS T S . R E P L A C E " 0 " R IN G S E A L IF L E A K A G E R E P L A C E BOTH " 0 " R IN G S E A L S. 7. TO RQ UE NUT TO 27 N-m (20 FT. L B S . ). R E P L A C E NUT IF L E A K A G E P E R S IS T S . 8. T O RQ U E S ID E C O V E R B O LTS TO 60 N-m (45 FT. L B S . ). 9. R E P L A C E A D J U S T E R PL U G " 0 " R IN G S E A L R E P L A C E S ID E C O V E R S E A L IF L E A K A G E P E R S IS T S . 10. REPLACE RO TARY VALVE A SSE M B LY . 11. R E P L A C E A D J U S T E R PLUG S E A L S. 12. SE A T B A L L F L U S H W IT H P U N C H A N D R E ST A K E . P E R S IS T S . IF S E E P A G E R E P L A C E H O U SIN G . 13. R E P L A C E BOTH P IT M A N SH A F T S E A L S. 14. R E P L A C E END PL U G " 0 " R IN G S E A L 15. R E P L A C E S ID E C O V E R " 0 " R IN G S E A L 16. R E P L A C E D U S T S E A L A N D P IT M A N SH A F T S E A L 17. TO RQ UE NUT TO 48 N-m (35 FT. L BS. >. R E P L A C E NUT IF LE A K A G E P E R S IS T S . Fig. 3B3-8--Gear and Pump Leak Diagnosis L IG H T TR UC K SE RV IC E M AN U AL 3B3-10 POWER STEERING SYSTEM MAINTENANCE AND ADJUSTMENTS LUBRICATION OF POWER STEERING PUMP Check the fluid level in the pum p reservoir according to the intervals listed in Section OB. Use only an approved power steering lubricant in the pump. NOTICE: Never use brake fluid in the power steering pum p, or dam age may occur. ADJUSTMENTS Power Steering Gear Adjustment Procedure A djustm ent of the steering gear in the vehicle is not recom m ended because of th e difficulty encountered in adjusting the worm thrust bearing preload and the confus­ ing effects of the hydraulic fluid in the gear. Since a gear adjustm ent is m ade only as a correction and not as a periodic adjustm ent, it is better to take the extra tim e and make the adjustm ent correctly the first time. Since a handling stability com plaint can be caused by improperly adjusted worm bearings as well as an improper gear over-center adjustm ent, it is necessary th at the steering gear assem bly be removed from the vehicle and both thrust bearing and over-center preload be checked and corrected as necessary. An in-vehicle check of the steering gear will not pin-point a thrust bearing looseness. Before any adjustm ents are m ade to the steering gear attem p t to correct com plaints of loose or hard steering, or other wheel disturbances, a careful check should be m ade of front end alignm ent, shock absorbers, wheel balance and tire pressure for possible steering system problems. See Diagnosis steps listed earlier in this section. Once it is determ ined to m ake adjustm ents, refer to Section 3B of the O verhaul M anual for specific instructions. STEERING GEAR HIGH POINT CENTERING 1. Set front wheels in straight ahead position. This can be checked by driving vehicle a short distance on a flat surface to determ ine steering wheel position at which vehicle follows a straig h t path. LIG H T TR UC K SE RV IC E M AN U AL 2. W ith front wheels set straight ahead, check position of m ark on w orm shaft designating steering gear high point. This m ark should be at the top side of the shaft at 12 o’clock position and lined up with the m ark in the coupling lower clamp. 3. On C, G and P series, if gear has been moved off high point when setting wheel in straight ahead position, loosen the adjusting sleeve clam ps on both left and right hand tie rods. Then turn both sleeves an equal num ber of turns in the same direction to bring gear back on high point. Turning the sleeves an unequal num ber of turns or in different directions will disturb the toe-in setting of the wheels. 4. On K series, if the gear has been moved off high point when setting wheels in straight ahead position, loosen the adjusting sleeve clamps on the connecting rod. Then turn sleeve to bring gear back on high point. 5. R eadjust toe-in as outlined in Section 3A (if necessary). 6. Be sure to properly orient sleeves and clamps, as shown in Section 3B 1, when fastening and torqueing clamps to proper specifications. PUMP BELT TENSION ADJUSTMENT 1. Loosen pivot bolt and pum p brace adjusting nuts. See Fig. 3B3-9. NOTICE: Do not move pum p by prying against reservoir or by pulling on filler neck, or dam age to the pump could occur. 2. Move pump, with belt in place until belt is tensioned to specifications as indicated by Tool J-23600 (Fig. 3B310). See Figure 3B 3-11. 3. Tighten pump brace adjusting nut. Then tighten pivot bolt nut. FLUID LEVEL ADJUSTMENT 1. Check oil level in the reservoir by checking the dipstick when oil is at operating te m p eratu re. On models equipped with remote reservoir, the oil level should be POWER STEERING SYSTEM m aintained approxim ately 1/2 to 1 inch from top with wheels in full left turn position. 2. Fill, if necessary, to proper level w ith G M Power Steering Fluid or equivalent. NOTICE: N ever use brake fluid in the power steering pum p, or dam age may occur. BLEEDING HYDRAULIC SYSTEM 1. Fill oil reservoir to proper level and let oil remain undisturbed for at least two minutes. 2. S ta rt engine and run only for about two seconds. 3. Add oil if necessary. 4. R epeat above procedure until oil level rem ains constant after running engine. 5. Raise front end of vehicle so th at wheels are off the ground. 6. Increase engine speed to approxim ately 1500 rpm. 7. T urn the wheels (off ground) right and left, lightly contacting the wheel stops. 8. A dd oil if necessary. 9. Lower the vehicle and turn wheels right and left on the ground. 10. C heck oil level and refill as required. 11. If oil is extrem ely foamy, allow vehicle to stand a few m inutes with engine off and repeat above procedure. a. C heck belt tightness and check for a bent or loose pulley. (Pulley should not wobble with engine running.) b. Check to m ake sure hoses are not touching any other parts of the truck, particularly sheet m etal except where design calls for a clam p. c. Check oil level, filling to proper level if necessary, following operations 1 through 10. This step and Step " d " are extrem ely im portant as low oil level an d /o r air in the oil are the most frequent causes of objectional pump noise. d. C heck the presence of air in the oil. If air is present, attem p t to bleed system as described in operations 1 through 10. If it becomes obvious th at the pum p will not bleed after a few trials, proceed as outlined under H ydraulic System Checks. 3B3-11 HYDRAULIC SYSTEM CHECKS The following procedure outlines methods to identify and isolate power steering hydraulic circuit difficulties. The test provides means of determ ining whether power steering system hydraulic parts are actually faulty. This test will result in readings indicating faulty hydraulic operation, and will help to identify the faulty component. Before perform ing hydraulic circuit test, carefully check belt tension, fluid level and condition of driving pulley. Power Steering System Test Engine m ust be at norm al operating tem p e ra tu re. Inflate front tires to correct pressure. All tests are made with engine idling, check idle adjustm ent and if necessary adjust engine idle speed to correct specifications listed in Section 6C and proceed as follows: 1. W ith engine N O T runnning disconnect pressure hose from pum p and install Tool J-5176 using a spare pressure hose between gauge and pump. G auge must be between shut-off valve and pump (Fig. 3B3-12), Open shut-off valve. * 2. Remove filler cap from pump reservoir and check fluid level. Fill pump reservoir to full m ark on dip stick. S tart engine and, m om entarily holding steering wheel against stop, check connections at Tool J-5176 for leakage. 3. Bleed system as outlined under M aintenance and A djustm ents. 4. Insert therm om eter (Tool J-5421) in reservoir filler opening. Move steering wheel from stop to stop several times until therm om eter indicates that hydraulic fluid in reservoir has reached tem perature of 150° to 170°F. NOTICE: To prevent scrubbing flat spots on tires, do not turn steering wheel more than five times without rolling vehicle to change tire-to-floor contact area. 5. S ta rt engine and check fluid level adding any fluid if required. W hen engine is at norm al operating tem pera­ ture, the initial pressure read on the gage (valve open) should be in the 80-125 PSI range. Should this pressure be in excess of 200 PSI - check the hoses for restrictions and the poppet valve for proper assembly. B E L T T E N S IO N 5/16 3/8" 15/32 W ID E W ID E W ID E NEW BELT 350 N Max. 80 Lbs. Max. 620 N Max. 140 Lbs. Max. 750 N Max. 165 Lbs. Max. USED BELT 200 N M in. 50 Lbs. M in. USED CO G G ED BELT 300 N 70 Lbs. M in. Min. 400 N 90 Lbs. POWER ST EER IN G a d a p TFR GAGE J-5176-01 j_22326 P R E SSU R E HOSE TO P /S G E A R P R E SSU R E HOSE FRO M PU M P Min. Min. 250 N M in. 60 Lbs. Min. Fig. 3B3-11—Belt Tension Chart Fig. 3B3-12--Checking Power Steering Pressures L IG H T T R U C K SE RV IC E M AN U AL 3B3-12 POWER STEERING SYSTEM 6. Close gate valve fully 3 times. Record the highest pressures attained each time. NOTICE: Do not leave valve fully closed for more than 5 seconds as the pump could be dam aged internally. a. If the pressures recorded are within the listed specs and the range of readings are within 50 PSI, the pump is functioning within specs. (Ex. Spec. 1250 1350 P S I-re a d in g s - 1270- 1275- 1280). b. If the pressures recorded are high, but do not repeat within 50 PSI, the flow controlling valve is sticking. Remove the valve, clean it and remove any burrs using crocus cloth or fine hone. If the system contains some dirt, flush it. If it is exceptionally dirty, both the pum p and the gear m ust be completely disassembled, cleaned, flushed and reassem bled before fu rth er usage. c. If the pressures recorded are constant, but more than 100 PSI, below the low listed spec., replace the flow control valve and recheck. If the pressures are still low, replace the rotating group in the pump. 7. If the pump checks within specifications, leave the valve open and turn (or have turned) the steering wheel into both corners. Record the highest pressures and com pare with the m axim um pum p pressures and com pare with the maximum pump pressure recorded. If this pressure cannot be built in either (or one) side of the gear, the gear is leaking internally and must be disassembled and repaired. See the current Overhaul M anual. 8. S hut off engine, remove testing gauge, spare hose, reconnect pressure hose, check fluid level an d /o r make needed repairs. ON-VEHICLE SERVICE Installation (Fig. 3B3-14) POWER STEERING GEAR Removal 1. D isconnect hoses at gear. W hen hoses are discon­ nected, secure ends in raised position ot prevent drainage of oil. C ap or tape the ends of the hoses to prevent entrance of dirt. 2. Install two plugs in gear fittings to prevent entrance of dirt. 3. Remove the flexible coupling to steering shaft flange bolts (G, C and K models) or the lower universal joint pinch bolt (P models). M ark the relationship of the universal yoke to the stub shaft. 4. M ark the relationship of the pitm an arm to the pitm an shaft. Remove the pitm an shaft nut or pitm an arm pinch bolt and then remove the pitm an arm from the pitm an shaft using Puller J-6632 (Fig. 3B3-13). 5. Remove the steering gear to fram e bolts and remove the gear assembly. 6. G, C and K Models - Remove the flexible coupling pinch bolt and remove the coupling from the steering gear stub shaft. NOTICE: See N O T IC E on page 1 of this section regarding the fasteners referred to in steps 1 ,3 ,4 and 5. 1. Install the flexible coupling onto the steering gear stub shaft, aligning the flat in the coupling with the flat on the shaft. Push the coupling onto the shaft until the stub sh aft bottom s on the coupling reinforcem ent. Install the pinch bolt and torque to specifications. NOTICE: The coupling bolt m ust pass through the shaft undercut, or dam age to the components could occur. 2. Place the steering gear in position, guiding the coupling bolt into the steering shaft flange. 3. Install the steering gear to fram e bolts and torque to specifications. 4. If flexible coupling alignm ent pin plastic spacers were used, make sure they are buttom ed on the pins, tighten the flange bolt nuts to specifications and then remove the plastic spacers. 5. If flexible coupling alignm ent pin plastic spacers were not used, center the pins in the slots in the steering shaft flange and then install and torque the flange bolt nuts to specifications. TOOL—J-5504 TO OL—J-6632 Fig. 3B3-13--Removing Pitman Arm L IG H T TR U C K SE RV IC E M A N U A L Fig. 3B3-14--Power Steering Gear Mounting-Typical POWER STEERING SYSTEM P Models a. Place the steering gear in position, guiding the stub shaft into the universal joint assembly and lining up the m arks m ade at removal. If a new gear was installed, line up the m ark on the stub shaft with the m ark on the universal yoke. b. Install the steering gear to fram e bolts and torque to specifications. c. Install the universal joint pinch bolt and torque to specification. The pinch bolt m ust pass through the shaft undercut. All Models 6. Install the pitm an arm onto the pitm an shaft, lining up the m arks m ade at removal. Install the pitm an shaft nut or pitm an arm pinch bolt and to rque to specifications. 7. Remove the plugs and caps from the steering gear and hoses and connect the hoses to the gear. Tighten the hose fittings to specified torque. 3B3-13 POWER STEERING PUMP (3B3-15 THROUGH 3B3-26) Removal 1. Disconnect hoses at pump. W hen hoses are discon­ nected, secure ends in raised position to prevent drainage of oil. C ap or tape the ends of the hoses to prevent entrance of dirt. On Models with rem ote reservoir, disconnect reservoir hose at pum p and secure in raised position. C ap hose pump fittings. 2. Install two caps at pum p fittings to prevent drainage of oil from pump. 3. Loosen bracket-to-pum p mounting nuts. 4. Remove pum p belt. 5. Remove pump from attaching parts and remove pump from vehicle. Installation 1. Postion pump assembly on vehicle and install attaching parts loosely. 2. Connect and tighten hose fittings. 3. Fill reservoir. Bleed pum p by turning pulley backward? (counter-clockw ise as viewed from front) until air bubbles cease to appear. 4. Install pump belt over pulley. 5. Tension belt as outlined under "Pum p Belt TensionA djustm ent" in this section. 6. B leed as o utlined u n d er “ B leeding P o w er Steering S y ste m .” Fig. 3 B 3 - 1 5 - P / S Pump M o u n tin g; C K 1 0 0 , C K 2 0 0 Fig. 3 B 3 -1 6 --P /S Pum p M oun tin g; C K 2 0 0 , C K 3 0 0 (03) with LE3 Engine with L25 Engine LIG H T T R U C K SERVICE M AN U AL 3B3-14 POWER STEERING SYSTEM Fig. 3 B 3 -1 7 --P /S Pump M o un tin g; C K 1 0 0 , C K 2 0 0 , Fig. 3 B 3 -2 0 --P /S Pump m ounting; C K 1 0 0 (03) with C K 3 0 0 - LE4, LG 9, LS9, LT9 (Exc. C 60, JB8) I F9 Enaine Fig. 3 B 3 -1 8 --P /S Pum p M o u n tin g; C K 1 0 0 , C K 2 0 0 , Fig. 3 B 3 -2 1 --P /S Pump M o u n tin g; G 1 0 0 , G 2 0 0 , C K 3 0 0 - LE4, LG9, LT9 an d C 6 0 G 3 0 0 with LE3 Engine Fig. 3 B 3 -1 9 --P /S Pump M o u n tin g; C l 00, C 2 0 0 , C 3 0 0 Fig. 3 B 3 -2 2 --P /S Pump M oun tin g; G 1 0 0 , G 2 0 0 , with LE8 Engine G 3 0 0 - LE4, LF4, LG9, LS9, LT9 L IG H T T R U C K SE RV IC E M A N U A L POWER STEERING SYSTEM Fig. 3 B 3 -2 3 --P /S Pump M o u n tin g; P200, P300 (42) with L25 Engine 3B3-15 Fig. 3 B 3 -2 6 --P /S Pump M o un tin g; P300 (32) with LE8 Engine POWER STEERING HOSES W hen servicing the power steering hoses be sure to align the hoses in their correct position as shown in Figs.* 3B3-27 through 3B3-42. It is im p o rtan t th a t the power steering hoses be installed correctly. Hoses installed out of position may be subjected to chafing or other abuses during sharp turns. Do not twist hoses unnecessarily during installation. NOTICE: Do not start engine with any power steering hose disconnected, or dam age to the components could occur. SPECIFICATIONS AND SPECIAL TOOLS Refer to Specifications and Special Tools at end of Section 3B4. Fig. 3 B 3 -2 4 --P /S Pump M o u n tin g; P200, P300 (42) with LT9 (Exc. JB8) Fig. 3 B 3 -2 5 --P /S Pum p M o un tin g; P200, P300 (32) with LT9 Engine LIG H T T R U C K SE RV IC E M AN U AL 3B3-16 POWER STEERING SYSTEM Fig. 3 B 3 - 2 7 - P / S Hose Routing; C K 100, C K 2 0 0 (03) with LE3 Engine with LE8 Engine L25 Engine JB8 Fig. 3 B 3 - 2 9 - P / S Hose Routing; C K 1 0 0 , C K 200, C K 300 - LE4, LG9, LS9, LT9 (Exc. C 60, JB8) LIG H T TR U C K SE R V IC E M A N U A L LT9 and JB8 POWER STEERING SYSTEM 3B3-17 Fig. 3 B 3 -3 3 --P /S Hose Routing; C K 100 (03) with LF9 Engine, a n d JB3, JB5 with LE3 Engine (Exc. H C 4 ) LE4, LG9, LF4, LS9, LT9 and JB7 HC4 and JB8 L IG H T T R U C K SERVICE M AN U AL 3B3-18 POWER STEERING SYSTEM Fig. 3 B 3 - 3 9 - P / S Hose Routing; P200, P300 (42) with Fig. 3 B 3 -4 1 --P /S Hose Routing; P 300 (32) with LT9 L25 Engine an d JB7 Engine Fig. 3 B 3 -4 0 --P /S H ose Routing; P200, P300 (42) with Fig. 3 B 3 -4 2 --P /S Hose Routing;P300 (32) with LE8 LT9 Engine an d JB7 Engine L IG H T TR U C K SE R V IC E M A N U A L STEERING C O L U M N S 3B4-1 SECTION 3B4 STEERING COLUMNS The following notice applies to one or more steps in the assembly procedure o f com ponents in this portion of the m anual as indicated at appropriate locations by the term inology "See Notice on page 1 of this Section". NOTICE: This fastener is an im portant attaching part in th at it could affect the perform ance of vital com ponents and systems, a n d /o r could result in m ajor repair expense. It m ust be replaced w ith one of the same part num ber or w ith an equivalent part if replacem ent becomes necessary. D o not use a replacem ent part of lesser quality or substitute design. T orque values m ust be used as specified during reassembly to assure proper retention of this part. CONTENTS G eneral D escrip tio n ............................................................................... ..3B4-1 D iag n o sis.....................................................................................................3B4-2 M aintenance and A dju stm ents..............................................................3B4-16 On-Vehicle Service....................... ............................................................3B4-18 C-Series, K -Series............................................................................... ..3B4-18 G-Series, P-S eries............................................................................... ..3B4-35 Specifications..............................................................................................3B4-51 Special T o o ls..............................................................................................3B4-52 GENERAL DESCRIPTION FUNCTION LOCKING COLUMNS T he function locking energy absorbing steering colum n includes three im portant features in addition to the steering function: 1. T he colum n is energy absorbing, designed to com press in a front-end collision to m inim ize the possibility of injury to the driver o f the vehicle. 2. T he ignition switch and lock are m ounted conveniently on the column. 3. W ith the colum n m ounted lock, the ignition, steering and gearshifting operation can be locked to inhibit theft o f the vehicle. T he function locking energy abosrbing colum n may be easily disassembled and reassembled. The serviceman should be aware that it is im portant th at only the specified screws, bolts and nuts be used as designated and th at they are tightened to their specified torque. This precaution will insure the energy absorbing action o f the assembly. O ver­ length bolts should not be used, as they may prevent a portion of the assembly from com pressing under impact. Equally as im portant is correct torque o f bolts and nuts. Care should be taken to assure that the bolts or nuts securing the colum n m ounting bracket to the instrum ent panel are torqued to the proper specification in order that the bracket will break away under impact. W hen the function locking energy absorbing colum n assembly is installed in a vehicle, it is no m ore susceptible to damage through usage than an ordinary column; however, when the colum n is removed, special care must be taken in handling this assembly. Only the specified wheel puller should be used. W hen the colum n is removed from the vehicle, such actions as a sharp blow on the end of the steering shaft or shift lever, leaning on the colum n assembly, or dropping o f the assembly could shear or loosen the plastic fasteners th at m aintain column rigidity. It is, therefore, im portant that the removal and installation and the disassembly and reassembly procedures be carefully followed when servicing the assembly. L IGHT T R U C K SE R V IC E M A N U A L 3B4-2 STEERING C O L U M N S Fig. 3 B 4 -1 ~ Ste e rin g Colu m n DIAGNOSIS GENERAL INFORMATION This section contains diagnostic inform ation to help locate the cause of the problem in the colum n. Reference should be m ade to the correct m ethod o f column disassembly, repair, adjustm ent and reassembly. Damaged, broken or deformed parts m ust be replaced w ith the correct replacem ent. To perform diagnostic procedures on the steering colum n upper end com ponents, it is not necessary to remove the colum n from the vehicle. The steering wheel, horn com ponents, directional signal switch, ignition switch and lock cylinder may be removed w ith the colum n rem aining in the vehicle as described in the Service M anual under "C om ponent P art Replacem ent". CAUTION: The outer mast jacket shift tube, steering shaft and instrument panel mounting bracket are designed as energy absorbing units. Because of the design of these components, it is absolutely necessary to handle the column with care when performing any service operation. Avoid hammering, jarring, dropping or leaning on any portion of the column. When reassembling the column components, use only the specified screws, nuts and bolts and tighten to specified torque. Care should be exercised not to use over-length screws or bolts as they may prevent a portion of the column from compressing under impact. Personal injury could result from lack of care when servicing the steering column. STEERING COLUMN ELECTRICAL ANALYZER J-23980 For C-Series and K-Series (Fig. 3B4-2) Tool J-23980 will help the technician analyze the steering colum n wiring harness for electrical problems. The tool in actuality eliminates the steering column, related wiring and com ponents; and replaces them with the tool itself. In this way disassembly of the colum n is not performed until the problem has been determ ined to be in the column. By moving the tester switch, (with the key in the "on" position), the various functions may be checked. The switch positions are "O F F ", "H O R N ", "L E FT Fig. 3B4-2~Steering Column Electrical Analyzer J -2 3 9 8 0 LIGHT TR U C K SE R V IC E M A N U A L STEERING C O L U M N S T U R N ", "R IG H T T U R N ", "K E Y B U Z Z E R ", and "H A Z A R D ". (Trucks do not incorporate a Key Buzzer Switch) if the systems function properly while using the tester, then the m alfunction has been narrow ed to the colum n w iring or com ponents. W hen this has been determ ined then the colum n m ay be serviced to correct the m alfunction. T o use the tool just unfasten the harm onica connector on the colum n and plug the harness from J-23980 into the vehicle chassis harness. The "A ", "B", and "C" term inals on the tester will overhang the chassis connector. This does not affect the test results. These term inals are for vehicles w ith cornering lights. Connect the single black jum per to a good ground. The tester is now ready for use (Fig. 3B4-2). COLLISION DIAGNOSIS (FIGS. 3B4-3 THROUGH 3B4-8) To determ ine if the energy absorbing steering colum n com ponents are functioning as designed, or if repairs are required, a close inspection should be made. A n inspection is called for in all cases where dam age is evident or whenever the vehicle is being repaired due to a front end collision. W henever a force has been exerted on the steering wheel or steering colum n, or its com ponents, inspection should also be made. If dam age is evident, the affected parts m ust be replaced. The inspection procedure for the various steering colum n com ponents on C and K trucks is as follows: Column Support Bracket D am age in this area will be indicated by separation of the m ounting capsules from the bracket. The bracket will have moved forward tow ard the engine com partm ent and will usually result in collapsing o f the jacket section of the steering column. 3B4-3 COLUMN JACKET Inspect jacket section of column for looseness, a n d /o r bends. SHIFTER SHAFT Separation of the shifter shaft sections will be internal and cannot be visually identified. Hold lower end of the "shifter shaft" and move "shift lever" on colum n through its ranges and up and down. If there is little or no movement o f the "shifter shaft", the plastic joints are sheared. Steering Shaft If the steering shaft plastic pins have been sheared, the shaft will rattle when struck lightly from the side and some lash may be felt when rotating the steering wheel while holding the rag joint. It should be noted that if the steering shaft pins are sheared due to m inor collision w ith no appreciable dam age to other components, th at the vehicle can be safely steered; however, steering shaft replacement is recommended. Because of the differences in the steering colum n types, be sure to refer to the set of instructions below which apply to the colum n being serviced. METHOD TO DETERMINE COLUMN COLLAPSE M easure distance between top of neutral-start switch window opening and the bottom of the upper jacket. The correct value is shown below: a. C-Truck 5 11/16" to 5 1/2". b. K -T ruck 5 11/16" to 5 1/2". i ifiU T t r i ICK " — * * * “"•AL 3B4-4 STEERING C O L U M N S SU RFA CE “A’ L Instrument Panel Bracket Capsule Damage NO TE: The bolt head m ust not contact surface “ A” . If contact is m ade, the capsule shear load will be increased. If this co n d itio n exists replace the bracket. AUTOMATIC TRANSMISSION COLUMNS LOCK S Y S T E M -W IL L NOT UNLOCK Cause Solution A. Lock bolt dam aged. A. Replace lock bolt. B. Defective lock cylinder. B. Replace or repair lock cylinder. C. Dam aged housing. C. Replace housing. D. Dam aged or collapsed sector. D. Replace sector. E. Dam aged rack. E. Replace rack. F. Shear Flange on secto r shaft collapsed. F. Replace. LOCK SYSTEM WILL NOT LOCK Cause Solution A. Lock bolt spring broken or defective. A. Replace spring. B. Dam aged sector to o th , or sector installed incorrectly. B. Replace, or install correctly. C. Defective lock cylinder. C. Replace lock cylinder D. Burr or lock b olt or housing. D. Remove Burr. E. Damaged housing. E. Replace housing. F. T ransm ission linkage adjustm ent incorrect. F. Readjust (see Sec. 7). G. Dam aged rack. G. Replace rack. H. I n te r f e r e n c e b e tw e e n b o w l a n d c o u p lin g ( tilt) . H. Adjust or replace as necessary. I. Ignition sw itch stuck. 1. Readjust or replace. J. A ctuator rod restricted or bent. J. Readjust or replace. LOCK SYSTEM - HIGH EFFORT Cause Solution A. Lock cylinder defective. A. Replace lock cylinder. B. Ignition sw itch defective. B. Replace sw itch. C. Rack preload spring broken or deform ed. C. Replace spring. D. Burrs on sector, rack, housing, support, tang o f shift gate or a ctu ato r rod coupling. D. Remove Burr. E. Bent sector shaft. E. Replace shaft. F. F. Replace rack G. Replace either or b oth. D istorted rack. G. M isa lig n m e n t o f h o u s in g to c o v e r ( t il t o n ly ). Fig. 3B 4-3-A utom atic Transmission Column Diagnosis Chart A LIG H T T R U C K SE R V IC E M A N U A L STEERING C O L U M N S LOCK SYSTEM - 3B4-5 HIGH EFFORT (CONT'D.) Cause Solution H. D is to rte d c o u p lin g slo t in r a c k ( tilt) . H. Replace rack. I. Bent or restricted actu ato r rod. I. Straighten remove restriction or replace. J. Ignition switch m ounting bracket bent. J. Straighten or replace. HIGH EFFORT LOCK CY LIN D ER - BETWEEN “OFF” AND "O FF-LOCK" POSITIONS Cause Solution A. Burr on tang o f shift gate. A. Remove burr. B. D istorted rack. B. Replace rack. STICKS IN “STA RT" POSITION Cause Solution A. A ctuator rod deform ed. A. Straighten or replace. B. Any high effo rt condition. B. Check item s under high effo rt section. KEY CAN NOT BE REM OVED IN “OFF-LOCK" POSITION Cause Solution A. Ignition switch is not set correctly. A. Readjust ignition sw itch. B. Defective lock cylinder. B. Replace lock cylinder. LOCK CYLINDER CAN BE REM OVED WITHOUT DEPRESSING RETAINER Cause Solution A. Lock cylinder w ith defective retainer. A. Replace lock cylinder. B. Lock cylinder w ith o u t retainer. B. C. Burr over retainer slot in housing cover. C. Remove burr. Replace lock cylinder. LOCK BOLT HITS SHAFT LOCK IN “O FF" AND "P A R K " POSITIONS Cause Solution A. Ignition sw itch is not set correctly. A. Readjust ignition sw itch. IGNITION SYSTEM - ELECTRICAL SYSTEM WILL NOT FUNCTION Cause Solution A. Defective fuse in “ accessory” circuit. A. Replace fuse. B. C onnector body loose or defective. B. Tighten or replace. C. Defective wiring. C. Repair or replace. Fig. 3B4-4-A utom atic Transmission Column Diagnosis Chart B LIGHT TRU C K SE R V IC E M A N U A L 3B4-6 STEERING C O L U M N S IGNITION SYSTEM - ELECTRICAL SYSTEM WILL NOT FUNCTION (CONT'D.) Cause Solution D. Defective ignition sw itch. D. Replace ignition sw itch. E. Ignition sw itch n o t adjusted properly. E. Readjust ignition sw itch. SWITCH WILL NOT ACTUATE M ECHAN ICALLY Cause Solution A. Defective ignition sw itch. A. Replace igntion sw itch. SWITCH CAN NOT BE SET CORRECTLY Cause Solution A. Sw itch a ctu ato r rod deform ed. A. R epair or replace sw itch a c tu a to r rod. B. B. S e c to r t o ra c k e n g a g e d in w ro n g t o o t h ( tilt) . Engage sector to rack correctly. NOISE IN COLUMN Cause Solution A. C oupling b o lts loose. A. T ighten pinch b o lts to specified torque. B. C olum n n o t c o rrectly aligned. B. Realign colum n. C. C oupling pulled apart. C. Replace coupling and realign colum n. D. Sheared in term ed iate shaft plastic jo in t; D. Replace or repair steering shaft and realign colum n. E. H orn c o n ta ct ring not lubricated. E. L ubricate w ith lubriplate. F. Lfcck o f grease on bearings or bearing surfaces. F. L ubricate bearings. G. Lower shaft bearing tight or frozen. G. Replace bearing. C heck shaft and replace if scored. H. Upper shaft tight or frozen. H. Replace housing assem bly. I. Shaft lock plate cover loose. I. J. Lock plate snap ring n o t seated. J. K. D efective buzzer dog cam on lock cylinder. K. Replace lock cylinder. T ighten three screws or, if missing, replace. CAUTION: Use specified screws. (15 in. lbs.) L. One click w hen in “ off-lock” position and the steering w heel is m oved. L. Replace snap ring. Check for p roper seating in groove. Norm al co n d itio n - lock b olt is seating. Fig. 3B 4-5-A utom atic Transmission Column Diagnosis Chart C LIGHT TR U C K SE R V IC E M A N U A L STEERING C O L U M N S 3B4-7 HIGH STEERING SHAFT EFFORT Cause Solution A. Colum n assem bly m isaligned in vehicle. A. Realign. B. Im properly installed or deform ed dust seal. B. Remove and replace. C. Tight or frozen upper or lower bearing. C. D. Flash on l.D. o f shift tube from plastic join t. Replace affected bearing or bearings. D. Replace shift tube. HIGH SHIFT EFFORT Cause Solution A. Colum n not aligned co rrectly in car. A. Realign. B. Im properly installed dust seal. B. Remove and replace. C. C. Lack ot grease on seal or bearing areas. Lubricate bearings and seals. D. Burr on upper or lower end o f shift tube,. D. Remove burr. E. E. Reassemble properly. L o w e r b o w l b e a rin g n o t a sse m b le d p r o p e rly ( tilt) . F . W ave w a sh e r w ith b u rrs ( t il t o n ly ). F. Replace wave washer. IMPROPER TRANSM ISSIO N SHIFTING Cause Solution A. Sheared shift tube jo in t. A. Replace shift tube assem bly. B. Im proper transm ission linkage adjustm ent. B. Readjust linkage. C. Loose lower shift lever. C. D. Im proper gate plate. D. Replace w ith correct part. E. Sheared lower shift lever weld. E. Replace tube assem bly. Replace shift tube assem bly. LASH IN MOUNTED COLUMN ASSEM BLY Cause Solution A. Instrum ent panel m ounting bolts loose. A. Tighten to specifications. (20 ft. Ibs.) B. Broken weld nuts on jac k et. B. Replace jac k et assem bly. C. C. Instrum ent panel b racket capsule sheared. Replace bracket assem bly. D. Instrum ent panel to jac k et m ounting bolts loose. D. Tighten to specifications. (15 ft. lbs.) E. L o o se sh o e s in h o u s in g ( t il t o n ly ). E. Replace. F. L o o se t ilt h e a d p iv o t p in s ( t il t o n ly ). F. G. L o o se sh o e lo c k p in in s u p p o r t ( t il t o n ly ). G. Replace. Replace. M ISCELLANEOUS Cause Solution A. Housing loose on jack et - will be noticed w ith ignition in “ O ff-L ock” and a torque applied to the steering wheel. A. Tighten four m ounting screws - (60 in. lbs.) B. Shroud loose on shift bowl. B. Bend tabs on shroud over lugs on bowl. Fig. 3B4-6--Automatic Transmission Column Diagnosis Chart D LIGHT T R U C K SER V IC E M A N U A L 3B4-8 STEERING C O L U M N S M A N U A L T R A N S M IS S IO N COLUM NS G E N E R A L INFORMATION All of the preceding diagnosis information for autom atic transmission will apply to the manual transmission. The following information is supplied in addition to and specifically for manual transmission columns. D R I V E R C A N L O C K S T E E R IN G SECO N D G EA R IN Cause Solution A. Defective upper shift lever. A. Replace shift lever. B. Defective shift lever gate. B. Replace shift lever gate. C. Loose relay lever on shift tube. C. Replace shift tube assembly. HIGH SHIFT EFFORT Cause Solution A. Column not aligned correctly in car. A. Realign column. B. Lower bowl bearing not assembled correctly. B. Reassemble correctly. C. Im properly installed seal. C. Remove and replace. D. Wave washer in lower bowl bearing defective. D. Replace wave washer. E. Im proper adjustm ent o f lower shift levers. E. Readjust (see Sec. 7). F. F. Lack ot grease on seal, bearing areas or levers. G. Damaged shift tube in bearing areas. Lubricate seal, levers and bearings. G. Replace shift tube assembly. IMPROPER TRANSMISSION SHIFTING Cause Solution A. Loose relay lever on shift tube. A. Replace shift tube assembly. Fig. 3B4-7-Manual Transmission Column Diagnosis LIGHT T R U C K SE R V IC E M A N U A L STEERING C O L U M N S 3B4-9 TILT COLUMNS GENERAL INFORMATION All of the preceding diagnosis will generally apply to tilt columns. The following is supplied in addition to and specifically for tilt columns. HOUSING SCRAPING ON BOWL Cause Solution A. Bowl bent or not concentric with hub. A. Replace bowl. STEERING WHEEL LOOSE Cause Solution A. Excessive clearance betw een holes in support or housing and pivot pin diameters. A. Replace either or both . B. Defective or missing anti-lash spring in spheres. B. Add spring or replace both. C. Upper bearing seat not seating in bearing. C. Replace both. D. Upper bearing inner race seat missing. D. install seat. F. Loose support screws. F. Tighten to 60 in. lbs. G. Bearing preload spring missing or broken. G. Replace preload spring. STEERING WHEEL LOOSE E V ER Y OTHER TILT POSITION Cause Solution A. Loose fit between shoe and shoe pivot pin. A. Replace both. NOISE WHEN TILTING COLUMN Cause Solution A. Upper tilt b um p er worn. A. Replace tilt bumper. B. Tilt spring rubbing in housing. B. Lubricate. STEERING COLUMN NOT LOCKING IN ANY TILT POSITION Cause Solution A. Shoe seized on its pivot pin. ivot pin. A. Replace shoe and-pivot pin. B. Shoe grooves may have burrs or dirt. B. Replace shoe. C. Shoe lock spring weak or broken. C. Replace lock spring. STEERING WHEEL FAILS TO RETURN TO TOP TILT POSITION Cause Solution A. Pivot pins are b ou n d up. A. Replace pivot pins. B. Wheel tilt spring is defective. B. Replace tilt spring. C. Turn signal switch wires t o o tight. C. Reposition wires. Fig. 3B4-8~Tilt Column Diagnosis LIGHT T R U C K SE R V IC E M A N U A L 3B4-10 STEERING C O L U M N S Fig. 3 B 4 -1 0 -C h e c k in g H arm onica Connector on Column Fig. 3 B 4 -9 -C h e c k in g Fuses on Fuse Block TURN SIGNAL DIAGNOSIS C AND K SERIES Figs. 3B4-9 Through 3B4-16 W hen a com plaint is m ade involving the turn signal system, it m ust first be determ ined w hether the problem is m echanical ojr electrical. If m echanical, the switch itself is at fault and m ust be repaired or replaced. If electrical, J23980 should be used to determ ine w hether the switch, or the chassis wiring is in need of repair or replacem ent. This diagnostic procedure has been designed to guide the m echanic through the proper diagnosis and repair of the turn signal system. The service section is to be used where assembly a n d /o r disassembly procedures are required. The wiring diagram , found in Section 12, should be used to trouble shoot the chassis and body wiring after the problem has been isolated. The nature of the custom er com plaint will generally point to the problem area. If all lamps light when hazard w arning is depressed, but flashing does not occur, replace hazard warning flasher. (On fuse block) (Figure 3B4-11). 4. If all directional lamps light when lane change or turn indicator is actuated, but no flashing occurs, replace the turn signal flasher. The above four steps will, in most cases, cure the common signal switch system troubles. If the system is still not operating correctly, use J-23980 to determ ine w hether the chassis wiring or the signal switch itself is at fault. Mechanical 1. If the custom er’s com plaint indicates the problem is in the switch, function check as to return from full left and full right turns. A ctuate the turn lever into a full tu rn position in either direction, then turn the steering wheel (m otor on - power steering) at least 1/4 turn in the direction indicated and then Electrical Chassis Electrical The most com m on tu rn signal system problems are generally electrical and may easily, be fixed by the replacem ent of fuses, bulbs, or flashers . First m ake these checks and replace any non-operative components. 1. Check fuses (Figure 3B4-9). Replace if blown. If new fuse blows, replace flasher in system. (There are 2 flashers in the signal switch system. The hazard warning flasher and tu rn signal flasher are located on the fuse block. 2. C heck for secure connection at the chassis to switch connector. T his is the harm onica connector on the colum n (Figure 3B4-10). Secure if loose. Check all individual wire terminals for proper seating in the connector bodies. Terminals should be locked in place. 3. Depress hazard w arning button and check all lights in signal switch system. Replace any which do not work. Fig. 3 B 4 -1 1 -C h e c k in g Hazard W arn ing Flasher LIGHT T R U C K SE R V IC E M A N U A L STEERING C O L U M N S 3B4-11 2. Check the return from lane change by holding the lever in lane change and releasing (both left and right). If the lever does not return to neutral, disassemble the upper part of the column. 3. If the hazard warning button cannot be depressed or released, the switch m ust be replaced. Switch Visual Inspection LANE CHANGE RETURN SPRING Fig. 3B 4-1 2--Checking Turn Signal Sw itch V isually back to center. D o this in both directions. If the lever does not return to the neutral position, disassemble the upper part of the colum n until the switch is visible. 1. W ith the upper part of the column disassembled so th at the signal switch is visible (Figure 3B4-12) check for missing springs. Replace any spring that is missing, inspecting the molded pins which secure them. If these pins are broken, the switch m ust be replaced. 2. Check the position of the switch in the bowl. If it appears cocked or crooked, loosen the securing screws (3) and visually inspect the switch. If any of the plastic is broken or badly deformed, the switch must be replaced. 3. If the switch appears undamaged, replace it being careful to seat the pilot into the housing, tighten the screws to 25 lbs. in. of torque. LIGHT T R U C K SER V IC E M A N U A L 3B4-12 STEERING C O L U M N S SIGNAL SWITCH DIAGNOSIS CONDITION Turn signal will not cancel Loose switch mounting screws Switch or anchor bosses broken Broken, missing or out of position detent, return or cancelling spring Uneven or incorrect cancelling cam to cancelling spring interference. (,120)/side A. A. B. A. B. C. D. Turn signal difficult to operate C. D. E. Turn signal will not indicate lane change A. B. C. Turn signal will not stay in turn position A. B. C. Hazard switch cannot be turned off CORRECTION POSSIBLE CAUSE A. B. Tighten to specified torque (25 in-lbs) Replace switch C. Reposition or replace springs as required D. Adjust switch position 1. If interference is correct and switch will still not cancel, replace switch. 2. If interference cannot be corrected by switch adjustment, replace cancelling cam. Actuator rod loose A. Yoke broken or distorted Loose or misplaced springs Foreign parts and/or materials Switch mounted loosely B. Tighten mounting screw (12 in-lb) Replace switch Broken lane change pressure pad or spring hanger Broken, missing or misplaced lane change spring Jammed base or wires Foreign material or loose parts impeding movement of yoke Broken or missing detent or cancelling springs None of the above Foreign material between hazard support cancelling leg and yoke C. D. E. Reposition or replace springs Remove foreign parts and/or material Tighten mounting screws (25 in-lbs) A. Replace switch B. Replace or reposition as required C. Loosen mounting screws, reposition base or wires and retighten screws (25 in-lbs) A. Remove material and/or parts B. Replace spring C. Replace switch A. Remove foreign material 1. No foreign material impeding function of hazard switch —replace turn signal switch Fig. 3B4-13~Turn Signal Switch Diagnosis Chart A LIGHT TR U C K S E R V IC E M A N U A L STEERING C O L U M N S 3B4-13 SIGNAL SWITCH DIAGNOSIS CONDITION Hazard switch will not stay on or difficult to turn off No turn signal lights POSSIBLE CAUSE A. C. Loose switch mounting screws Interference with other components Foreign material C. D. None of the above D. A. Defective or blown fuse Inoperative turn signal flasher Loose chassis to column connector Disconnect column to chassis connector. Connect new switch to chassis and operate switch by hand. If vehicle lights now operate normally, signal switch is inoperative If vehicle lights do not operate check chassis wiring for opens, grounds, etc. A. B. B. C. D. E. Turn indicator lights on, but not flashing CORRECTION A. B. B. C. D. Replace turn flasher Note: There are two flashers in the system. Consult manual for location. Connect securely and check operation Replace turn signal switch Replace signal switch A. B. Loose chassis to column connection Inoperative turn signal switch To determine if turn signal switch is defective, substitute new switch into circuit and operate switch by hand. If the vehicle's lights operate normally, signal switch is inoperative If the vehicle's lights do not operate, check light sockets for high resistance connections, the chassis wiring for opens, grounds, etc. B. E. Replace fuse and check operation Replace turn signal flasher Connect securely, check operation Replace signal switch Repair chassis wiring as required using manual as guide Inoperative turn , flasher D. Remove foreign material Replace switch E. A. C. Tighten mounting screws (25 in-lbs) Remove interference C. D. E. Repair chassis wiring as required using manual as guide Fig. 3B4-14-Turn Signal Switch Diagnosis Chart B LIGHT T R U C K SE R V IC E M A N U A L 3B4-14 STEERING COLUMNS CONDITION Front or rear turn signal lights not flashing SIGNAL SWITCH DIAGNOSIS POSSIBLE CAUSE A. Burned out fuse A. B. Burned out or damaged turn signal bulb High resistance connection to ground at bulb socket B. L o o s e c h a s s is to D. C. D. E. F. Stop light not on when turn indicated column connector Disconnect column to chassis connector. Connect new switch into system and operate switch by hand. If turn signal lights are now on and flash, turn signal switch is inoperative. If vehicle lights do not operate, check chassis wiring harness to light sockets for opens, grounds, etc. C. E. F. A. Burned out fuse A. B. Loose column to chassis connection Disconnect column to chassis connector. Connect new switch into system without removing old. Operate switch by hand. If brake lights work with switch in the turn position, signal switch is defective If brake lights do not work check connector to stop light sockets for grounds, opens, etc. B. C. D. Turn indicator panel lights not flashing CORRECTION A. B. C. P ned out bulbs High resistance to ground at bulb socket Opens, grounds in wiring harness from front turn signal bulb socket to indicator lights C. Replace fuse and check operation Replace bulb Remove or repair defective connection and check operation Connect securely and check operation Replace turn signal switch. Repair chassis wiring as required using manual as guide Replace fuse and check operation Connect securely and check operation Replace signal switch D. Repair connector to stop light circuits using manual as guide. A. B. Replace bulbs Replace socket C. Locate and repair as required. Use shop manual as guide. Fig. 3B4-1 5-Turn Signal Switch Diagnosis Chart C LIGHT TR U C K SE R V IC E M A N U A L STEERING C O L U M N S 3B4-15 SIGNAL SWITCH DIAGNOSIS CONDITION Turn signal lights flash very slowly A. B. C. D. E. F. Hazard signal lights will not flash —turn signal functions normally CORRECTION POSSIBLE CAUSE Inoperative turn signal flasher System charging voltage low High resistance ground at light sockets Loose chassis to column connection Disconnect column to chassis connector. Connect new switch into system without removing old. Operate switch by hand. If flashing occurs at normal rate, the signal switch is defective. If the flashing rate is still extremely slow, check chassis wiring harness from the connector to light sockets for grounds, high resistance points, etc. A. Blown fuse B. Inoperative hazard warning flasher Loose chassis to column connection Disconnect column to chassis connector. Connect new switch into system without removing old. Depress the hazard warning button and observe the hazard warning lights. If they now work normally, the turn signal switch is defective. If the lights do not flash, check wiring harness "K" lead (brown) for open between hazard flasher and harmonica connector. If open, fuse block is defective. C. D. E. A. C. D. E. F. C. D. E. Replace turn signal flasher I ncrease voltage to specified. See Sec. 6Y Repair high resistance grounds at light sockets Connect securely and check operation Replace signal switch Locate and repair as required. Use manual as guide. See Section 12 Replace fuse and check operation Replace hazard warning flasher Connect securely and check operation Replace the turn signal switch Replace fuse block (See Sec. 12) Fig. 3B4-16-Turn Signal Switch Diagnosis Chart D LIGHT TRU C K SE R V IC E M A N U A L 3B4-16 STEERING C O L U M N S MAINTENANCE AND ADJUSTMENTS STEERING WHEEL ALIGNMENT On all series vehicles, check steering gear for high point centering as shown in Sections 3B2 and 3B3 before checking steering wheel alignment. 1. Set wheels in straight ahead position by driving vehicle a short distance. 2. N ote steering wheel position. If off m ore than 1 inch from center (Fig. 3B4-17), remove steering wheel as outlined under "Steering W heel - R em oval", center high point on gear, reposition and reinstall the wheel. STEERING COLUMN LOWER BEARING ADJUSTMENT G and P Series Only 1. Loosen clam p on steering shaft. 2. Applying 50 lb. force to the steering wheel end of the steering shaft, adjust clam p to obtain clearances indicated in Figure 3B4-18. 3. Tighten clam p bolt to specified torque. SHIFTER TUBE ADJUSTMENT G and P Series Only 3-Speed Transmission 1. Loosen adjusting ring attaching screws and clamp bolt. 2. R otate adjusting ring to give .005" end play between adjusting ring and first and reverse shifter lever (Fig. 3B419). 3. Tighten attaching screws and clam p bolt. Automatic Transmission 1. Place the shift tube lever in "N eutral" or "D rive". 2. Loosen adjusting ring clam p screws and rotate the shift tube adjusting ring to obtain .33" to .36" clearance between the shift tube lever and adjusting ring (Fig. 3B420). 3. Tighten the adjusting ring clam p screws to 70 in. lbs. LIGHT T R U C K SE R V IC E M A N U A L STEERING C O L U M N S Fig. 3 B 4 -1 9 ~ S h ift Tube A djustm ent-3 Speed M an u al Transm ission 3B4-17 Fig. 3 B 4 -2 0 --S h ift Tube A d justm ent-A utom atic Transm ission LIGHT TR U C K SER V IC E M A N U A L 3B4-18 STEERING C O L U M N S ON-VEHICLE SERVICE INDEX C-Series and K -S eries.......................................................3B4-18 Steering W h e e l............................................................... ..3B4-18 Flexible C oupling.......................................................... ..3B4-18 Interm ediate Shaft............................... ............................3B4-19 D irectional Signal S w itch.............................................3B4-20 Lock C y lin d er................................................................ .3B4-21 Ignition Sw itch............................................................... .3B4-22 Steering C o lu m n .............................................................3B4-23 R em oval......................................................................... .3B4-24 Disassembly, Standard C olum n.......... .................... .3B4-24 Disassembly, T ilt C o lu m n ........................................ .3B4-29 Installation, M andatory Sequence.......................... .3B4-34 G-Series and P-Series.......................................................3B4-35 STEERING WHEEL Removal Steering W h eel............................................................... Flexible C oupling.......................................................... Interm ediate Shaft......................................................... Colum n U pper B earin g ........ ....................................... Colum n Lower B earing ............................................... Tilt Colum n Bearing H ousing.................................... D irectional Signal Sw itch............................................ Steering C o lu m n ............................................................ Rem oval......................................................................... Disassembly, Standard C olum n............................... Disassembly, Tilt C o lu m n ........................................ Installation, M andatory Sequence.......................... 3B4-35 3B4-35 3B4-36 3B4-38 3B4-38 3B4-39 3B4-40 3 B 4-41 3 B 4-41 3B4-41 3B4-44 3B4-48 Installation NOTICE: See N O T IC E on page 1 of this section regarding the fasteners referred to in step 1. 1. D isconnect battery ground cable. 2. Rem ove horn button cap. 3. Rem ove snap ring and steering wheel nut. 4. Using tool J - l859-03,thread puller anchor screws into holes provided on steering wheel. See Fig. 3B4-21. Turn center bolt of tool clockwise to remove wheel. 1. W ith turn signal in neutral position, align m arks and set wheel onto steering shaft. Torque steering shaft nut to specifications and install snap ring. NOTICE: D o not ham m er on puller, or dam age could occur to the com ponents. The tool centering adapters need not be used. 2. Place steering wheel horn button on wheel and snap into proper position. NOTICE: D o not over torque shaft nut or steering wheel rub may result. 3. Connect battery ground cable. STEERING COUPLING (FLEXIBLE TYPE) Removal (Fig. 3B4-22) 1. Remove the coupling to steering shaft flange bolt nuts. CAPTURING STRAP COUPLING TO STEERING SHAFT FLANGE BOLTS Fig. 3B4-21-Steering Wheel Removal Fig. 3B4-22~Flexible Type Steering Coupling LIGHT T R U C K 8E RV ICE M A N U A L STEERING C O L U M N S OW ER BEARING BLOCKS 3B4-19 BOLT COVER SNAP RING ft I UPPER SHAFT CLAMP TENSION NUT QDD IKJn Fig. 3 B 4 -2 3 -S te e rin g S h a ft Interm ediate Coupling 2. Remove the coupling clam p bolt. This is a special bolt and will require a 12 pt. socket or box wrench. 3. Remove the steering gear to fram e bolts and lower the steering gear far enough to remove the flexible coupling. It is not necessary to disconnect the pitm an arm from the pitm an shaft. 4. T ap lightly on the flexible coupling with a soft m allet to remove the coupling from the steering gear worm shaft. Installation NOTICE: See N O T IC E on page 1 of this section regarding the fasteners referred to in steps 2, 4 and 5. 1. Install the flexible coupling onto the steering gear w orm shaft, aligning the flat on the shaft with the flat in the coupling. Push the coupling onto the w orm shaft until the coupling reinforcem ent bottom s against the end of the worm. 2. Install the special bolt into the split clam p and torque to specifications. NOTICE: The bolt m ust pass through the shaft undercut, or dam age could occur to the components. 3. Place the steering gear into position, guiding the flexible coupling bolts into the proper holes in the steering shaft flange. 4. Install and tighten the steering gear to frame bolts. 5. Install the coupling to flange bolt nuts and washers and torque to specifications. Be sure to m aintain a coupling to flange dimension o f .250" to .375". The coupling alignm ent pins should be centered in the flange slots. INTERMEDIATE STEERING SHAFTS WITH POT JOINT COUPLINGS Removal (Fig. 3B4-23) 1. Remove the lower shaft flange to flexible coupling bolts. 2. Remove upper shaft to interm ediate coupling bolt. 3. If necessary, remove the steering gear to frame bolts and lower the steering gear far enough to remove the interm ediate shaft assembly. It is not necessary to remove Fig. 3 B 4 -2 4 -C h e c k in g Coupling Pin C entering the pitm an arm from the pitm an shaft. Disassembly 1. M ark cover to shaft relationship. Pry off snap ring and slide cover from shaft. 2. Remove bearing blocks and tension spring from pivot pin. 3. Clean grease off pin and end of shaft. Scribe location m ark on pin on same side as chamfer in shaft. 4. Supporting shaft assembly securely, with cham fer up, press pin out of shaft with arbor press. NOTICE: D o not drive pin out with ham m er. This could cause sticky or binding bearings when reassembled. 5. Remove seal clam p and slide seal off end of shaft. Assembly 1. Be sure all parts are free of dirt. Slide seal onto steering shaft. W ith lip of seal against step in shaft clamp seal. 2. Press pin back into shaft from cham fered side. Locate pin in shaft using scribe m ark as reference. NOTICE: Pin m ust be centered within .012 in. or binding in the coupling could result. 3. Check centering of pin (Fig. 3B4-24). a. Place just enough 3/8" flat washers on pin to prevent bearing block from bottom ing when installed. b. M easure distance from end of pin to top of bearing with micrometer. LIGHT T R U C K SE R V IC E M A N U A L 3B4-20 STEERING C O L U M N S Fig. 3B 4-26--R em ovin g Lock Plate Retaining Ring Removal (Fig. 3B4-25) Fig. 3 B 4 -2 5 -D ire c tio n a l Signal Sw itch 1. Remove the steering wheel as outlined under "Steering Wheel - Removal". 2. Remove the colum n to instrum ent panel trim cover. 3. Position screwdriver blade into cover slot. Pry up c. Remove bearing and washers and place same bearing and out to free cover from lock plate. and washers on other end of pin. M easure distance from end 4. Screw the center post of Lock Plate Compressing of pin to top of bearing. If m icrom eter readings in Steps b Tool J-23653 onto the steering shaft as far as it will go. and c differ m ore than .012, repeat last part o f Step 2 and Compress the lock plate by turning the center post nut recheck. clockwise (Fig. 3B4-26). Pry the round wire snap ring out 4. Apply a liberal am ount of wheel bearing grease to of the shaft groove and discard the ring. Remove Tool Jinside and outside of bearing blocks and inside of cover. 23653 and lift the lock plate off the end of the shaft. 5. Position tension spring and bearing blocks on pin. NOTICE: If the colum n is being disassembled on the 6. Slide cover over bearing blocks aligning reference bench, with the snap ring removed the shaft could slide m ark on cover w ith m ark on shaft. Install seal into end of out of the lower end of the m ast jacket, damaging the cover and secure with snap ring retainer. shaft assembly. Installation NOTICE: See N O T IC E on page 1 of this section regarding the fasteners referred to in steps 1, 3 and 4. 5. Slide the directional signal cancelling cam, upper bearing preload spring and thrust w asher off the end of the shaft. 1. Install the interm ediate shaft assembly onto the steering shaft, aligning the flat on the shaft with the flat in the coupling. Install the pot jo in t clam p bolt and torque to specifications. 2. Lift the steering gear into position, guiding the flexible coupling bolts into the shaft flange holes. 3. Install the steering gear to fram e bolts and torque to specifications. 4. Install the flexible coupling to steering shaft flange bolt lockwashers and nuts. Check th at the coupling alignment pins are centered in the flange slots and then torque the coupling bolts to specifications. DIRECTIONAL SIGNAL SWITCH The directional signal switch can be removed w ith the steering colum n in the vehicle and w ithout disturbing any of the colum n mountings. Fig. 3B4-27~Removing Directional Signal Wire Protector LIGHT T R U C K SE R V IC E M A N U A L STEERING C O L U M N S Fig. 3 B 4 -3 0 -ln s ta llin g Snap Ring Fig. 3B 4 -2 8 ~ R e m o v in g Directional Signal Sw itch Assem bly 6. Remove the directional signal lever screw and rem ove the lever. 7. Push the hazard w arning knob in and unscrew the knob. 8. Remove the three switch m ounting screws. 9. All Columns - Pull the switch connector out of the bracket on the jacket and feed switch connector through colum n support bracket and pull switch straight up, guiding the wiring harness through the colum n housing and protector. 10. Remove wire protector by pulling dow nw ard out of colum n with pliers using tab provided (Fig. 3B4-27). Tilt Column - Position the direction signal and shifter housing in the "low" position. Remove the harness cover by pulling tow ard the lower end of the colum n, be careful not to dam age the wires. 11. Remove the three switch m ounting screws and pull the switch straight up, guiding the wiring harness and cover through the column housing (Fig. 3B4-28). 3B4-21 Installation CAUTION: It is extremely important that only the specified screws, bolts and nuts be used at assembly, or personal injury could result. Use of overlength screws could prevent a portion of the assembly from compressing under impact. 1. All except Tilt - Be sure that the wiring harness is in the protector. Feed the connector and cover down through the housing and under the m ounting bracket (colum n in vehicle). Tilt - Feed the connector down through the housing and under the m ounting bracket. Then install the cover on the harness. 2. Install the three m ounting screws and clip the connector to the bracket on the jacket (Fig. 3B4-29). 3. Install the colum n to instrum ent panel trim plate. 4. Install the hazard warning knob and directional signal lever. 5. M ake certain that the switch is in "N eutral" and the hazard warning knob is out. Slide the thrust washer, upper bearing preload spring and cancelling cam onto the upper end of the shaft. 6. Place the lock plate onto the end of the shaft. Screw the center post of Lock Plate Compressing Tool J-23653 onto the steering shaft as far as it will go. Place a N EW snap ring over the center post. Place the "C" bar over the center post and then compress the lock plate by turning the nut clockwise. Slide the new snap ring down the tapered center post and into the shaft groove (Fig.3B4-30). Remove Tool J-23653. Always use a new snap ring when reassembling. 7. Place cover on the lock plate and snap into position. 8. Install the steering wheel as outlined under "Steering W heel-Installation". LOCK CYLINDER Fig. 3B4-29-lnstalling Switch Connector Onto Jacket Clips The lock cylinder is located on the upper right hand side of the column. The lock cylinder should be removed in the "R U N " position only. LIGHT T R U C K SER V IC E M A N U A L 3B4-22 STEERING C O L U M N S LOCK CYLINDER INSTALLATION DISASSEMBLE ASSEMBLE 1. Place lock in “run”. 1. 2. Remove lock plate, turn signal switch and buzzer switch (see service manual.) 2. Push lock all the way in. 3. Install screw. Tighten to 4.5 N*m for regular columns2.5 N*m for adjustable columns. 3. Remove screw & lock cylinder. CAUTION: If screw is dropped on removal, it could fall into the column, requiring complete disassembly to retrieve the screw. Rotate as shown, align cylinder key with keyway in housing. LOCK CYLINDER SET To-assemble — Rotate to stop while holding cylinder. HOUSING CYLINDER KEY LOCK RETAINING SCREW Fig. 3 B 4 -3 1 -L o ck C ylind er Removal Replacement 1. Remove the steering wheel as outlined under "Steering W heel - Rem oval". 2. Rem ove the directional signal switch as outlined under "D irectional Signal Switch - Rem oval". It is not necessary to com pletely remove the directional signal switch from the colum n. Pull the switch rearw ard far enough to slip it over the end o f the shaft - do not pull the harness out o f the colum n. 3. Refer to Fig. 3B4-31 for details on replacem ent of lock cylinder. IGNITION SWITCH The ignition switch is m ounted on top of the colum n jacket near the front of the dash. F o r anti-theft reasons, the switch is located inside the channel section o f the brake pedal support and is completely inaccessible w ithout first lowering the steering colum n (see steering colum n removal). The switch is actuated by a rod and rack assembly. A portion of the rack is toothed and engages a gear on the end of the lock cylinder, thus enabling the rod and rack to be moved axially (w ith respect to the colum n) to actuate the switch when the lock cylinder is rotated. detent, which is the "Lock" position. 3. Remove the two switch screws and remove the switch assembly. Installation 1. Before replacing the switch, be sure th at the lock is in the "Lock" position (Fig. 3B4-32); if it is not, a screwdriver (placed in the locking rod slot) can be used to move the switch to "Lock". 2. Install the activating rod into the switch and assemble the switch on the column; tighten the m ounting screws. Removal 1. Lower the steering colum n as outlined under "Steering Colum n Removal" later in this section. It is not necessary to rem ove the steering wheel. If the steering colum n is not removed from the vehicle, be sure th at it is properly supported, before proceeding. 2. The switch should be positioned in "Lock" position before removing. If the lock cylinder has already been removed, the actuating rod to the switch should be pulled up until there is a definite stop, then moved down one SWITCH IN LO C K PO SITIO N Fig. 3 B 4 -3 2 -lg n itio n Sw itch Assem bly LIGHT T R U C K SE R V IC E M A N U A L STEERING C O L U M N S 3B4-23 CAUTION: Use only the specified screws since over-length screws could prevent a portion of the assembly from compressing under impact, which could result in personal injury. 3. Reinstall the steering colum n assembly following the "M andatory Installation Sequence" outlined later in this section. STEERING COLUMN To perform service procedures on the steering colum n upper end components, it is not necessary to remove the colum n from the vehicle. T he steering wheel, horn com ponents, directional signal switch, and ignition lock cylinder may be removed with the colum n remaining in the vehicle as described earlier in this section. CAUTION: The outer mast jacket shift tube, steering shaft and instrument panel mounting bracket are designed as energy absorbing units. Because of the design of these components, it is absolutely necessary to handle the column with care when performing any service operation. Avoid hammering, jarring, dropping or leaning on any portion of the column. When reassembling the column components, use only the specified screws, nuts and bolts and tighten to specified torque. Care should be exercised in using over-length screws or bolts as they may prevent a portion of the column from compressing under impact. Fig. 3 B 4 -3 3 ~ A u to m a tic Transm ission Ind icato r ConnectionCK-Typical of the "shifter shaft", the plastic joints are sheared. SteeringShaft If the steering shaft plastic pins have been sheared, the shaft will rattle when struck lightly from the side and some lash may be felt when rotating the steering wheel while holding the rag joint. It should be noted that if the steering shaft pins are sheared due to m inor collision the vehicle can be safely steered; however, steering shaft replacem ent is recommended. Because of the differences in the steering colum n types, be sure to refer to the set of instructions below which apply to the colum n being serviced. Inspection To determ ine if the energy absorbing steering colum n com ponents are functioning as designed, or if repairs are required, a close inspection should be made. Inspection is called for in all cases where dam age is evident or whenever the vehicle is being repaired due to a front end collision. W henever a force has been exerted on the steering wheel or steering colum n, or its com ponents, inspection should also be made. If dam age is evident, the affected parts m ust be replaced. The inspection procedure for the various steering colum n com ponents on all C and K Series T rucks is as follows: ColumnSupportBracket D am age in this area will be indicated by separation of the m ounting capsules from the bracket. The bracket will have moved forward tow ard the engine com partm ent and will usually result in collapsing of the jacket section of the steering column. ColumnJacket Inspect jacket section o f colum n for looseness, a n d /o r bends. ShifterShaft Separation of the shifter shaft sections will be internal and cannot be visually identified. H old lower end of the "shifter shaft" and move "shift lever" on colum n through its ranges and up and down. If there is little or no m ovement LIGHT T R U C K SE R V IC E M A N U A L 3B4-24 STEERING C O L U M N S Removal F ro n t o f dash m ounting plates m ust be loosened whenever the steering colum n is to be lowered from the instrum ent panel. 1. D isconnect the battery ground cable. 2. Remove the steering wheel as outlined under "Steering W heel R em oval". 3. Remove the nuts and washers securing the flanged end of the steering shaft to the flexible coupling. 10. Remove the two colum n bracket-to-instrum ent panel nuts and carefull remove from vehicle. A dditional help should be obtained to guide the lower shift levers through the firewall opening. C and K Series, Standard Column - (Fig. 3B4-40) Disassembly 1. Remove the four dash panel bracket-to-colum n screws and lay the bracket in a safe place to prevent damage to the m ounting capsules. 2. Place the column in a vise using both weld nuts of either Set A or B as shown in Figure 3B4-41. The vise jaws m ust clamp onto the sides of the weld nuts indicated by arrow s shown on Set B. NOTICE: D o not place the colum n in a vise by clamping onto one weld nut of both sets A and B or by clamping onto the sides not indicated by arrows, since dam age to the colum n could result. 4. D isconnect the transm ission control linkage from the colum n shift tube levers. 5. Disconnect the steering colum n harness at the connector. D isconnect the neutral-start switch and back-up lam p switch connectors if so equipped. 6. Remove the floor pan trim cover screws and remove the cover. 7. Remove the transm ission indicator cable, if so equipped (Fig. 3B4-33). 8. Remove the screws securing the two halves of the floor pan cover; then rem ove the screws securing the halves and seal to the floor pan and remove the covers (Fig. 3B434). 9. Move the front seat as far back as possible to provide m axim um clearance. 3. Remove the D irectional Signal Switch, Lock Cylinder, and Ignition Switch as outlined previously in this section. 4. Column Shift Models - D rive out the upper shift lever pivot pin and remove the shift lever. 5. Remove the upper bearing th ru st washer. Remove the four screws attaching the turn signal and ignition lock housing to the jacket and remove the housing assembly (Fig. 3B4-42). 6. Remove the thrust cap from the lower side of the housing. 7. Lift the ignition switch actuating rod and rack assembly, the rack preload spring and the shaft lock bolt and spring assembly out of the housing (Fig. 3B4-43). 8. Remove the shift lever detent plate (shift gate). 9. Remove the ignition switch actuator sector through the lock cylinder hole by pushing firmly on the block tooth of the sector with a blunt punch or screwdriver (Fig. 3B444). 10. Remove the gearshift lever housing and shroud from the jacket assembly (transm ission control lock tube housing and shroud on floor shift models). 11. Remove the shift lever spring from the gearshift lever housing (lock tube spring on floor shift models). 12. Pull the steering shaft from lower end of the jacket assembly. LIGHT T R U C K SE R V IC E M A N U A L STEERING C OLU M NS STEERING COLUMN RETAINER NUT, Hexagon Jam COVER, Shaft Lock RING, Retaining 6. LOCK, Steering Shaft 7. CAM ASM, Turn Signal Cancelling 8. SPRING, Upper Bearing 9. SCREW, Pan Head Cross Recess 10. SWITCH ASM, Turn Signal 11. PROTECTOR, Wiring 12. SCREW, Hex Washer Head Tapping 13. WASHER, Thrust 14. BEARING ASM 17. HOUSING, Steering Column 18. SHAFT, Sector 19. SECTOR, Switch Actuator 20. SPRING, Rack Preload 21. CUP, Thrust 22. RACK ASM, Rod & 23. SCREW, Dimmer Switch Mounting 24. SWITCH ASM, Dimmer 25. SCREW, Flat Head Cross Recess 26. GATE, Shift Lever 27. WASHER, Spring Thrust 28. BOLT ASM, Spring & 29. SPRING. Upper Shift Lever 1. 2. 3. 4. 5. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 61. 62. 67. 68. 3B4-25 BOWL, Gearshift Lever SHROUD, Shift Bowl BEARING, Bowl Lower JACKET ASM, Steering Column SCREW, Washer Head SWITCH ASM, Ignition SEAL, Dash TUBE ASM, Shift WASHER, Spring Thrust SPRING, Shift Tube Return ADAPTER, Lower Bearing RETAINER, Bearing Adapter CLIP, Lower Bearing Adapter BEARING ASM SCREW ASM, Lockwasher & SPACER, Lower Shift Lever LEVER, Lower Shift BUSHING ASM, Steering Shaft RING, Retaining SHAFT ASM, Steering SCREW, Flat Head ROD, Dimmer Switch Actuator WASHER, Wave PLATE, Support & Alignment LOCK CYLINDER SET, Strg Coumn SCREW, Lock Retaining Fig. 3B4-40a-Std. Column; Auto. Trans, or 3-Speed LIGHT TR U C K SE R V IC E M A N U A L 3B4-26 S TE E RI NG C O L U M N S 1. 2. 3. 4. 5. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. ROD, Switch Actuator RACK, Switch Actuator SPRING, Rack Preload SECTOR, Switch Actuator HOUSING, Steering Column A/ASHER, Thrust SCREW, Hex Washer Head Tapping SWITCH ASSEMBLY, Turn Signal SCREW, Pan Head Cross Recess SPRING, Upper Bearing DAM ASM, Turn Signal Cancelling LOCK, STEERING SHAFT RING, Retaining COVER, Shaft Lock MUT, Hexagon Jam RETAINER SCREW, Pan Head Cross Recess SHROUD, Steering Column WASHER, Spring Thrust BOLT ASSEMBLY, Spring SPRING, Key Release LEVER, Key Release 25. WASHER, Wave 26. SHAFT ASSEMBLY, Steering 27. RING, Retaining 30. SEAL, Jacket & Dash Bracket 32. JACKET ASSEMBLY, Sleeve 33. SWITCH ASSEMBLY, Ignition 34. SCREW, Washer Head 49. BEARING ASM 50. RETAINER, Upper Bearing 51. SCREW, Flat Head 58. BOWL. Floor Shift 59. PROTECTOR, Wiring 62. ADAPTER, Lower Bearing 63. BEARING ASM 64. CLIP, Lower Bearing Adapter 65. RETAINER, Bearing Adapter 66 . LOCK CYLINDER SET, Strg Column 67. SCREW, Lock Retaining 23. 24. Fig. 3B4-40b-Std. Column, 4-Speed Trans. LIGHT T R U C K SE R V IC E M A N U A L STEERING C O L U M N S Fig. 3 B 4 - 4 1—Installing Steering Column in Vise 13. Remove the two screws holding the back-up switch or neutral-safety switch to the colum n and remove the switch. 14. Rem ove the lower bearing retainer clip (Fig. 3B445). 15. Automatic and Floorshift Columns - Remove the lower bearing retainer, bearing adapter assembly, shift tube th ru st spring and washer. The lower bearing may be rem oved from the adapter by light pressure on the bearing outer race. Slide out the shift tube assembly. Manual Transmission - C olum n Shift - Remove the lower bearing adapter, bearing and the first reverse shift lever. The lower bearing m ay be rem oved from the adapter by light pressure on the bearing outer race. Remove the three screws from bearing at the lower end and slide out the shift tube assembly. Remove the gearshift housing lower bearing from the upper end o f the m ast jacket. 3B4-27 6. Install the gearshift housing lower bearing. Insert the bearing from the very end of the jacket. Aligning the indentations in the bearing with the projections on the jacket (Fig. 3B4-47). If the bearing is not installed correctly, it will not rest on all of the stops provided. 7. Install the shift lever spring into the gearshift lever (or lock tube) housing. Install the housing and shroud assemblies onto the upper end of the m ast jacket. R otate the housing to be sure it is seated in the bearing. 8. W ith the shift lever housing in place, install the turn signal and lock cylinder housing onto the jacket. The gearshift housing should be in "Park" position and the rack pulled downward. Be sure the turn signal housing is seated on the jacket and drive the four screws. 9. Press the lower bearing into the adapter assembly. 10. Insert the shift tube assembly into the lower end of the jacket and rotate until the upper shift tube key slides into the housing keyway. 11. Automatic and Floor shift Columns Assemble the spring and lower bearing and adapter assembly into the bottom of the jacket. H olding the adapter in place, install the lower bearing reinforcem ent and retainer clip. Be sure the clip snaps into the jacket and reinforcem ent slots. 12. Manual Transmission - Column Shift Loosely attach the three screws in the jacket and shift tube bearing. Assemble the 1st-Reverse lever and lower bearing and adapter assembly into the bottom of the jacket. Holding the adapter in place, install the bearing reinforcem ent and retaining clip. Be sure the retaining clip snaps into the jacket and reinforcem ent slots. Refer to Fig. 3B4--48 for adjustm ent procedure. Assembly of Standard Columns A pply a thin coat o f lithium soap grease to all friction surfaces. 1. Install the sector into the tu rn signal and lock cylinder housing. Install the sector in the lock cylinder hole over the sector shaft with the tang end to the outside of the hole. Press th e sector over the shaft with a blunt tool. 2. Install the shift lever detent plate onto the housing. 3. Insert the rack preload spring into the housing from the bottom side. The long section should be tow ard the handw heel and hook onto the edge of the housing (Fig. 3B4-46). 4. Assemble the locking bolt onto the crossover arm on the rack and insert the rack and lock bolt assembly into the housing from the bottom w ith the teeth up (tow ard hand-w heel) and tow ard the centerline of the colum n (Fig. 3B4-43). Align the 1st tooth on the sector with the 1st tooth on the rack; if aligned properly, the block teeth will line up when the rack assembly is pushed all the way in. 5. Install the th ru st cup on the bottom hub of the housing. Fig. 3B 4 -4 2 ~ R e m o v in g Turn Signal Housing LIGHT T R U C K SE R V IC E M A N U A L 3B4-28 STEERING C O L U M N S SHIFT GATE RACK LOCK BOLT LOCK BOLT SPRING THRUST CUP SECTOR Fig. 3 B 4 -4 3 ~ T u rn S ig nal Housing Assem bly Fig. 3 B 4 -4 5 -R e m o v in g Low er Bearing Retainer Fig. 3 B 4 -4 4 -R e m o v in g Ignition Sw itch A c tuator Sector Fig. 3 B 4 -4 6 -ln s ta llin g Rack Preload Spring 13. Install the neutral-safety or back-up switch as outlined in Section 8 of this m anual. 14. Slide the steering shaft into the colum n and install the upper bearing thrust washer. 15. Install the tu rn signal switch, lock cylinder assembly and ignition switch as previously outlined in this section. 16. Install the shift lever and shift lever pivot pin. 17. Remove the colum n from the vise. 18. Install the dash bracket to the column; torque the screws to specifications. Fig. 3 B 4 -4 7 ~ ln s ta llin g G earshift Housing Low er Bearing LIGHT TR U C K SE R V IC E M A N U A L STEERING C O L U M N S _IVIAAOI A. TO REDUCE CLEARANCE SLIDE THE CLAMPING SC REW S AROUND THE M A S T JACKET IN THE DIRECTION OF ARROW A. A. TO REDUCE CLEARANCE SLIDE THE CLAMPING SC R EW S AROUND THE M A ST JACKET IN THE DIRECTION OF ARROW A. .M A S T JACKET .2 -3 SHIFT LEVER .PICK UP LEVER 1 ST-REV. SHIFT LEVER B. TO INCREASE CLEARANCE I -2 -3 SHIFT LEVER -PICK UP LEVER B. TO INCREASE CLEARANCE SLIDE THE CLAMPING SC R EW S AROUND THE M A S T JAC KET IN THE DIRECTION OF ARROW B. SLIDE THE CLAMPING SC R EW S AROUND THE M A S T JACKET IN THE DIRECTION OF ARROW B. 3B4-29 ALIGNMENT LEVER .0 0 5 IN. SHIM UPPER STRG. SHAFT SPACER \ L LOWER MAST LOWER BEARING JACKET BEARING RETAINER "LOWER M AST JACKET BEARING LOWER BEARING RETAINER AD JU S TM EN T PROCEDURE 1. WITH THE TRANSMISSION IN NEUTRAL DISCON­ NECT THE TRANSMISSION RODS. 2. TEST FOR R O TATIO NAL DRAG BY TURNING THE S HIFT LEVER (INSIDE TRUCK) THROUGH THE 2-3 S HIFT ARC. DRAG MEASURED AT THE S HIFT KNOB MUST BE NO MORE THAN 2.0 LBS. IF DRAG IS MORE THA N 2.0 LBS. CORRECTIONS MUST BE MADE BEFORE PROCEEDING W ITH THIS ADMUSTMENT. 3. LOOSEN THE THREE CLAMPING SCREWS. 4. INSTALL A .005 IN. THICK SHIM BETWEEN THE SPACE AND EITHER OF THE SHIFT LEVERS. THE ABOVE ILLUSTRATIO N SHOWS THE SHIM BE­ TWEEN THE SPACER AND THE 2-3 SHIFT LEVER. 5. SLIDE THE CLAMPING SCREWS IN DIRECTIO N OF ARROW B U N T IL THE SYSTEM IS LOOSE. THEN SLIDE THE SCREWS IN OPPOSITE DIRECTIO N U N T IL A D E FIN ITE DRAG IS FELT AT THE 1STREV. SHIFT LEVER. 6. TIG HTEN THE CLAMPING SCREWS. 7. REMOVE THE SHIM. 8. REINSTALL THE TRANSMISSION RODS. A D JU S TM EN T PROCEDURE 1. WITH THE TRANSMISSION IN NEUTRAL DISCON­ NECT THE TRANSMISSION RODS. 2. TEST FOR RO TATIO NAL DRAG BY TUR NING THE SHIFT LEVER (INSIDE TRUCK) THROUGH THE 2-3 S HIFT ARC. DRAG. MEASURED AT THE SHIFT KNOB, MUST BE NO MORE THAN 2.0 LBS. IF DRAG IS MORE THA N 2.0 LBS. CORRECTIONS MUST BE MADE BEFORE PROCEEDING WITH THE ADJUSTMENT. 3. LOOSEN THE THREE CLAMPING SCREWS. 4. INCREASE CLEARANCE BY SLIDING THE CLAMP­ ING SCREWS IN DIRECTIO N OF ARROW "B" ABOVE UN TIL THE 1ST-REV. SHIFT LEVER COMPLETELY FREE OF DRAG. 5. DECREASE CLEARANCE BY SLIDING THE CLAMP­ ING SCREWS IN DIRECTIO N OF ARROW "A " ABOVE U N TIL A SLIGHT DRAG IS FELT AT THE 1ST-REV. SHIFT LEVER. 6. TIG HTEN THE THREE CLAMPING SCREWS. 7. RECONNECT THE TRANSMISSION RODS NOTE: IF NO PROBLEM W ITH STEERING COLUMN DRAG IS IN V O L V E D , THIS ADJUSTMENT CAN BE MADE BY DISCONNECTING ONLY THE 1ST. REV. TRANSMISSION ROD AND O M ITTING STEP 2. NOTE: IF THERE IS NO PROBLEM W ITH STEERING COLUMN DRAG. THIS ADJUSTMENT CAN BE MADE BY DISCONNECTING O NLY THE 1ST. REV. TRANSMISSION ROD AND OMITTING STEP. 2. Fig. 3 B 4 -4 8 -A d ju s tin g Low er Bearing-Typical “I ,-n Disassembly-Tilt Columns (Fig. 3B4-49) Steps 3-14 m ay be perform ed w ith the steering colum n in the vehicle. 1. Remove the four screws retaining the dash m ounting bracket to the colum n and set the bracket aside to protect the breakaw ay capsules. 2. M ount the colum n in a vise using both weld nuts o f either Set A or B as shown in Figure 3B4-41. The vise jaw s m ust clamp onto the sides of the weld nuts indicated by arrow s shown on Set B. NOTICE: D o not place the colum n in a vise by clam ping onto only one weld nut, by clam ping onto one weld n u t of both Sets A and B or by clam ping onto the sides not indicated by arrows, since dam age to the colum n could result. . , -. < v 6. Install the tilt release lever and place the colum n in the full "up" position. Remove the tilt lever spring retainer using a # 3 phillips screwdriver that just fits into the slot opening. Insert the phillips screwdriver in the slot, press in approxim ately 3 /1 6 ", turn approximately 1/8 tu rn counterclockwise until the ears align with the grooves in the housing and remove the retainer, spring and guide (Fig. 3B4-50). 7. Remove the pot joint to steering shaft clam p bolt and remove the interm ediate shaft and pot joint assembly. Push the upper steering shaft in sufficiently to remove the steering shaft upper bearing inner race and seat. Pry off the lower bearing retainer clip and remove the bearing reinforcement, bearing and bearing adapter assembly from the lower end of the m ast jacket. 8. Remove the upper bearing housing pivot pins using Tool J-2 1854-1 (Fig. 3B4-51). 4. Remove the tilt release lever. Drive out the shift lever pivot pin and remove the shift lever from the housing. 9. Install the tilt release lever and disengage the lock shoes. Remove the bearing housing by pulling upward to extend the rack full down, and then moving the housing to the left to disengage the ignition switch rack from the actuator rod. 5. Rem ove the three tu rn signal housing screws and remove the housing. 10. Remove the steering shaft assembly from the upper end of the column. 3. Remove the directional signal switch, lock cylinder and ignition switch as outlined previously in this section. LIGHT T R U C K SE R V IC E M A N U A L 3B4-30 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 16. 17. STEERING C O L U M N S S T E E R IN G C O L U M N B E A R IN G ASM PIN , Release Lever S P R IN G , Release Lever S P R IN G , Shoe PIN , Pivot P IN , Dowel S H A F T , Drive SHO E, Steering Wheel Lock SHO E, Steering Wheel Lock S P R IN G , Lock Bolt B O L T, Lock B E A R IN G ASM SCREW , Oval Head Cross Recess R A CE, Inner 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 38. 39. 40. 41. 18. S E A T , Upper Bearing Inner Race 43. 19. S W ITC H A SM , Turn Signal 20. SCREW , Binding HD. Cross Recess 44. 45. 21. 22. 23. 24. 46. 47. 48. 49. C A M A SM , Turn Sig. Cancelling LO C K , Shaft C O V E R , Shaft Lock N U T , Hexagon Jam 25. R IN G , Retaining 50. S P R IN G , Upper Bearing P R O T E C T O R , Wiring C O V E R , Lock Housing (Painted) S H IE L D , T ilt Lever Opening R E T A IN E R , Spring SP R IN G , Wheel T ilt G U ID E , Spring SCREW , Hex. Washer Head R IN G , Retaining SEC TO R , Switch Actuator H O U S IN G , Steering Column S P R IN G , Rack Preload R A C K , Switch Actuator L E V E R , Shoe Release A C T U A T O R A SM , Ignition Switch S P R IN G , Shift Lever W A S H E R , Wave P L A T E , Lock W A S H E R , Thrust R IN G , S hift Tube Retaining SCREW, Oval Head Cross Recess G A T E , Shift Lever SUPPO RT, Strg. Column Housing 51. SCREW, Support 52. PIN , Dowel 53. S H A F T ASM , Lower Steering 54. SPHER E, Centering 55. S P R IN G , Joint Preload 56. S H A F T A SM , Race & Upper 57. SCREW, Wash. Hd. 58. SW ITCH ASM , Ignition 59. JA C K E T ASM , Steering Column 60. 61. 62. 63. 64. C LIP, Lower Bearing Adapter SEA L, Dash TU B E ASM , Shift R E T A IN E R , Bearing Adapter B E A R IN G ASM 65. 66. 77. 84. 85. 86. 87. A D A P T E R , Lower Bearing R E T A IN E R SCREW, Flat Head S H R O U D , Gearshift Bowl BOW L, Gearshift Lever LOCK C Y L IN D E R SET, Strg Column SCREW, Lock Retaining Fig. 3B4-49a~Tilt Column With Auto. Trans. LIGHT T R U C K SE R V IC E M A N U A L STEERING C O L U M N S 1. 2. 3. 4. 5. 6. 7. 8. B E A R IN G ASM PIN , Release Lever S P R IN G , Release Lever S P R IN G , Shoe P IN , Pivot PIN , Dowel S H A F T , Drive SHOE, Steering Wheel Lock 9. SHO E, Steering Wheel Lock 10. SPR IN G , Lock Bolt 11. B O LT, Lock 12. B E A R IN G ASM S H IE L D , T ilt Lever Opening C O V E R , Lock Housing SCREW , Oval Head Cross Recess R A C E, Inner 19. SE A T , Upper Bearing Inner Race 20. S W ITC H ASM , Turn Signal 13. 14. 17. 18. 21. SCREW , Binding H D Cross Recess 22. CAM A SM , Turn Signal Cancelling 23. LOCK, Shaft 24. C O V E R , Shaft Lock 25. N U T , Hexagon Jam (9 /1 6 -1 8 ) R E T A IN E R R IN G , Retainer S P R IN G , Upper Bearing P R O T E C T O R , Wiring R E T A IN E R , Spring S P R IN G , Wheel T ilt G U ID E , Spring SCREW, Hex. Washer Head SEC TO R , Switch Actuator PIN , Pivot H O U S IN G , Steering Column S P R IN G , Rack Preload R A C K , Switch Actuator L E V E R , Shoe Release 42. A C T U A T O R ASM , Switch 43. S H R O U D , Column Housing 44. S PR IN G , Key Release 26. 27. 28. 29. 30. 31. 32. 33. 35. 36. 37. 39. 40. 41. 45. L E V E R , Key Release 46. P L A T E , Lock 47. SUPPO RT, Steering Column Housing 48. SCREW, Support 49. SCREW, Oval Head Cross Recess 50. P L A T E , Shroud Retaining 3B4-31 51. PIN , Dowel 52. S H A F T ASM, Lower Steering 53. SPHER E, Centering 54. S PR IN G , Joint Preload 55. SPHER E, Centering 56. S H A F T ASM, Race & Upper 57. S W ITC H ASM, Ignition 61. JA C K E T ASM, Sleeve & 62. B E A R IN G ASM, Adapter 8t 63. B E A R IN G ASM 64. SPACER, Steering Shaft 65. SE A L, Jacket 8i Dash Bracket 66. B R A C K E T ASM, Column Dash 76. SCREW , Washer Head (# 1 0 -2 4 x .25) 77. SCREW , Flat Head (# 1 0 -2 4 x .31) 81. C LIP, Lower Bearing Adapter 82. A D A P T E R , Lower Bearing 83. B E A R IN G ASM 84. R E T A IN E R , Bearing Adapter 85. LOCK C Y L IN D E R SET, Strg Column 86. SCREW, Lock Retaining Fig. 3B4-49b-Tilt Column With 4-Speed LIGHT T R U C K SE R V IC E M A N U A L 3B4-32 STEERING C O L U M N S M Fig. 3 B 4 -5 0 ~ R e m o v in g T ilt Lever Spring R etainer Fig. 3B 4 -5 2 ~ R e m o v in g S h ift Tube 11. Disassemble the steering shaft by rem oving the centering spheres and the anti-lash spring. 12. Rem ove the transm ission indicator wire, if so equipped. 13. Remove the four steering shaft bearing housing support to gearshift housing screws and remove the bearing housing support. Remove the ignition switch actuator rod. 14. Remove the shift tube retaining ring w ith a screwdriver and then remove the th ru st washer. 15. Install Tool J-23072 into the lock plate, m aking sure that the tool screws have good thread engagement in the lock plate. Then, turning the center screw clockwise, force the shift tube from the housing (Fig. 3B4-52). Remove the shift tube (transm ission control lock tube on floor shift models) from the lower end o f the m ast jacket. Remove Tool J-23072. 16. Remove the bearing housing support lock plate by sliding it out of the jacket notches, tipping it down tow ard the housing hub at the 12 o’clock position and sliding it under the jacket opening. Remove the wave washer. 17. All Columns - Remove the shift lever housing from the m ast jacket (transm ission control lock tube housing on floor shift models). Remove the shift lever spring by winding the spring up with pliers and pulling it out. On floor shift models, remove the spring plunger. 18. Disassemble the bearing housing as follows: a. Remove the tilt lever opening shield. b. Remove the lock bolt spring by removing the retaining screw and moving the spring clockwise to remove it from the bolt (Fig. 3B4-53). c. Remove the snap ring from the sector drive shaft. W ith a small punch, lightly tap the drive shaft from the sector (Fig. 3B4-54). Remove the drive shaft, sector and lock bolt. Remove the rack and rack spring. d. Remove the tilt release lever pin with a punch and ham m er. Remove the lever and release lever spring. To relieve the load on the release lever, hold the shoes inward and wedge a block between the top of the shoes (over slots) NOTICE: W hen rem oving the shift tube, be sure to guide the lower end through the slotted opening in the m ast jacket. If the tube is allowed to interfere w ith the jacket in any way, dam age to the tube and jacket could result. Fig. 3B4-51--Removing Bearing Housing Pivot Pins Fig. 3B4-53--Replacing Lock Bolt Spring LIGHT TR U C K SE R V IC E M A N U A L STEERING C O L U M N S Fig. 3B 4 -5 4 ~ R e m o v in g Sector Drive Shaft and bearing housing. e. Remove the lock shoe retaining pin w ith a punch and ham m er. Remove the lock shoes and lock shoe springs. W ith the tilt lever opening on the left side and shoes facing up, the four slot shoe is on the left. f. Remove the bearings from the bearing housing only if they are to be replaced. Remove the separator and balls from the bearings. Place the housing on work bench and with a pointed punch against the back surface of the race, carefully ham m er the race out o f the housing until a bearing puller can be used. Repeat for the other race. Assembly-Tilt Columns A pply a thin coat of lithium grease to all friction surfaces. 3B4-33 Fig. 3 B 4 -5 6 ~ ln s ta llin g Bearing Housing shoes for pin installation. c. Install the shoe release lever, spring and pin. To relieve the load on the release lever, hold the shoes inward and wedge a block between the top of the shoes (over slots) and bearing housing. d. Install the sector drive shaft into the housing. Lightly tap the sector onto the shaft far enough to install the snap ring. Install the snap ring. e. Install the lock bolt and engage it w ith the sector cam surface. Then install the rack and spring. The block tooth on the rack should engage the block tooth on the sector (Fig. 3B4-55). Install the external tilt release lever. f. Install the lock bolt spring and retaining screw (Fig. 3B4-50). Tighten the screw to 35 in. lbs. 1. If the bearing housing was disassembled, repeat the 2. Install the shift lever spring into the housing by following steps: windng it up with pliers and pushing it into the housing. a. Press the bearings into the housing, if removed, On floor shift models, install the plunger, slide the gearshift using a suitable size socket. Be careful not to dam age the lever housing onto the m ast jacket. housing or bearing during installation. b. Install the lock shoe springs, lock shoes and shoe pin in the housing. Use an approxim ate .180" rod to line up the SHIFT BOWL J 2 3 0 7 3 -3 J 23073 4 W AVEn W ASH ER LO C K PLATE J 23 07 3-1 J 2 3 0 7 3 -2 FLAT W ASHER UPPER SHIFT TUBE Fig. 3B4-55—Installing Lock Bolt and Rack Assemblies Fig. 3B4-57—Installing Shift Tube LIGHT TRU C K SE R V IC E M A N U A L 3B4-34 STEERING C O L U M N S 3. Install the bearing support lock plate wave washer. 4. Install the bearing support lock plate. W ork it into the notches in the jacket by tipping it tow ard the housing hub at the 12 o ’clock position and sliding it under the jacket opening. Slide the lock plate into the notches in the jacket. 5. Carefully install the shift tube into the lower end of the m ast jacket. Align keyway in the tube w ith the key in the shift lever housing. Install the wobble plate end o f Tool J-23073 into the upper end of the shift tube far enough to reach the enlarged portion o f the tube. Then install the adapter over the end of the tool, seating it against the lock plate. Place the n u t on the threaded end of the tool and pull the shift tube into the housing (Fig. 3B4-57). Rem ove Tool J-23073. NOTICE: D o not push o r tap on the end of the shift tube. Be sure th at the shift tube lever is aligned with the slotted opening at the lower end of the m ast jacket or dam age to the shift tube and m ast jacket could result. 6. Install the bearing support thru st w asher and retaining ring by pulling the shift lever housing up far enough to compress the wave washer. 7. Install the bearing support by aligning the "V" in the support with the "V" in the jacket. Insert the screws through the support and into the lock plate and torque to 60 lbs. in. 8. Align the lower bearing adapter with the notches in the jacket and push the adapter into the lower end of the m ast jacket. Install lower bearing, bearing reinforcem ent and retaining clip, being sure th at the clip is aligned with the slots in the reinforcem ent, jacket and adapter. 9. Install the centering spheres and anti-lash spring in the upper shaft. Install the lower shaft from the same side of the spheres that the spring ends protrude. 10. Install the steering shaft assembly into the shift tube from the upper end. Carefully guide the shaft through the shift tube and bearing. 11. Install the ignition switch actuator rod through the shift lever housing and insert in the slot in the bearing support. Extend the rack dow nw ard from the bearing housing. 12. Assemble the bearing housing over the steering shaft and engage the rack over the end of the actuator rod (Fig. 3B4-56). 13. W ith the external release lever installed, hold the lock shoes in the disengaged position and assemble the bearing housing over the steering shaft until the pivot pin holes line up. 14. Install the pivot pins. 15. Place the bearing housing in the full "up" position and install the tilt lever spring guide, spring and spring retainer. W ith a suitable screwdriver, push the retainer in and turn clockwise to engage in the housing. 16. Install the upper bearing inner race and race seat. 17. Install the tilt lever opening shield. 18. Remove the tilt release lever,install the tu rn signal housing and torque the three retaining screws to 45 lbs. in. 19. Install the tilt release lever and shift lever. D rive the shift lever pin in. 20. Install the lock cylinder, tu rn signal switch and ignition switch as outlined previously in this section. 21. Align the groove across the upper end of the pot joint with the flat on the steering shaft. Assemble the interm ediate shaft assembly to the upper shaft. Install the clam p and bolt and torque the nut to specifications. NOTICE: The clamp bolt m ust pass through the shaft undercut, or damage may occur to the components. 22. Install the neutral-safety switch or back-up switch as outlined in Section 12 of this m anual. 23. Install the four dash panel bracket to colum n screws and torque to specifications. CAUTION: Be sure th a t the slotted openings in the bracket (for the mounting capsules) face the upper end of the steering column. CO LUM N INSTALLATIO N-M ANDA TO R Y SEQUENCE M andatory Preliminary Instructions 1. Assemble lower dash cover (A) and upper dash cover (B) to seal (C) w ith "C arrots" (part of seal). 2. A ttach bracket (D ) to jacket and tighten four bolts (E) to specified torque. LIGHT T R U C K SE R V IC E M A N U A L STEERING C O L U M N S 3B4-35 Mandatory Installation Sequence 1. Position colum n in body and position flange to rag jo in t and install lock washers and nuts (F) (M ay be tightened to specified torque at this time). Coupling (G ) on m anual steering m ust be installed prior to colum n installation. 2. Loosely assemble (2) capsules nuts (H) at the instrum ent panel bracket (D). 3. Position lower clam p (J) and tighten attaching nuts (K ) to specified torque. 4. Tighten two nuts (H ) at capsules to specified torque. 5. Install seal (C) and covers (A and B) to dash. 6. Install attaching screws (L) and tighten to specified torque. 7. Tighten two nuts (F) at capsules to specified torque if not already done. 8. Remove plastic spacers from flexible coupling pins. 9. Install transm ission indicator cable on colum n autom atics. 10. Install the instrum ent panel trim cover. 11. Connect the transm ission control linkage at the shift tube levers. 12. Install the steering wheel as outlined previously in this section. 13. Connect the battery ground cable. STEERING COUPLING (FLEXIBLE TYPE) M andatory System Requirements Removal (Fig. 3B 4-60) 1. Pot joint operating angle m ust be 1 1/2° + 4°. 2. Flexible coupling m ust not be distorted greater than -j- .06 due to pot jo in t bottom ing, in either direction. nuts. STEERING COLUMN SERVICE FOR G AND P SERIES STEERING WHEEL Removal 1. Disconnect battery ground cable. 2. Remove horn button or shroud, receiving cup, belleville spring and bushing and m ark steering wheel to steering shaft relationship. 3. Remove snap ring, and steering shaft nut. 4. Use Tool J-1859-03 to remove wheel (Fig. 3B4-59). Installation Fig. 3 B 4 -5 9 ~ S te e rin g W h eel Rem oval-Typical 1. Remove the coupling to steering shaft flange bolt 2. Remove the coupling clamp bolt. This is a special bolt and will require a 12 pt. socket or box wrench. 3. Remove the steering gear to fram e bolts and lower the steering gear far enough to remove the flexible coupling. It is not necessary to disconnect the pitm an arm from the pitm an shaft. 4. T ap lightly on the flexible coupling with a soft mallet to remove the coupling from the steering gear wormshaft. CAPTURING STRAP NOTICE: See N O T IC E on page 1 of this section regarding the fastener referred to in step 2. D irectional signal control assembly m ust be in neutral position when assembling steering wheel to prevent dam age to cancelling cam and control assembly. 1. Place the steering wheel onto the steering shaft, aligning the m arks m ade at removal. 2. Position into place and secure to proper torque with nut. Install snap ring. 3. Install horn button assembly. 4. C onnect battery ground cable. COUPLING TO STEERING SHAFT FLANGE BOLTS Fig. 3B4-60~Flexible Type Steering Coupling LIGHT T R U C K SE R V IC E M A N U A L 3B4-36 STEERING C O L U M N S BEARING Fig. 3 B 4 -6 1 -S te e rin g S h aft In term ed iate Coupling Installation NOTICE: See N O T IC E on page 1 of this section regarding the fasteners referred to in steps 2, 4 and 5. 1. Install the flexible coupling onto the steering gear wormshaft, aligning the flat on the shaft w ith the flat in the coupling. Push the coupling onto the w orm shaft until the coupling reinforcem ent bottom s against the end of the worm. 2. Install the special bolt into the split clam p and torque to specifications. NOTICE: T he bolt m ust pass through the shaft undercut,or dam age m ay occur to the components. 3. Place the steering gear into position, guiding the flexible coupling bolts into the proper holes in the steering shaft flange. 4. Install and tighten the steering gear to fram e bolts. 5. Install the coupling to flange bolt nuts and washers and torque to specifications. Be sure to m aintain a coupling to flange dim ension o f .250" to .375". The coupling alignm ent pins should be centered in the flange slots. INTERMEDIATE STEERING SHAFTS WITH POT JOINT COUPLINGS Fig. 3 B 4 -6 2 ~ C h e c k in g Coupling Pin Centering may cause reassembled. 5. sticky or binding bearings when Remove seal clamp and slide seal off end of shaft. Assembly 1. Be sure all parts are free of dirt. Slide seal onto steering shaft. W ith lip of seal against step in shaft clamp seal. 2. Press pin back into shaft from cham fered side. Locate pin in shaft using scribe m ark as reference. NOTICE: Pin m ust be centered w ithin .012 in. or binding in the coupling could result. Removal (Fig. 3B4-61) 1. Remove the lower shaft flange to flexible coupling bolts. 2. Remove upper shaft to interm ediate coupling bolt 3. If necessary, remove the steering gear to fram e bolts and lower the steering gear far enough to remove the interm ediate shaft assembly. It is not necessary to remove the pitm an arm from the pitm an shaft. Disassembly 1. M ark cover to shaft relationship. Pry off snap ring and slide cover from shaft. 2. Rem ove bearing blocks and tension spring from pivot pin. 3. Clean grease off pin and end of shaft. Scribe location m ark on pin on sam e side as cham fer in shaft. 4. Supporting shaft assembly securely, with cham fer up, press pin out o f shaft with arbor press. NOTICE: 3. Check centering of pin (Fig. 3B4-62). a. Place just enough 3/8" flat washers on pin to prevent bearing block from bottom ing when installed. b. M easure distance from end of pin to top of bearing with micrometer. c. Remove bearing and washers and place same bearing and washers on other end of pin. M easure distance from end of pin to top of bearing. If m icrom eter readings in Steps b and c differ m ore than .012, repeat last part of Step 2 and recheck. 4. Apply a liberal am ount of wheel bearing grease to inside and outside of bearing blocks and inside of cover. 5. Position tension spring and bearing blocks on pin. 6. Slide cover over bearing blocks aligning reference m ark on cover with m ark on shaft. Install seal into end of cover and secure with snap ring retainer. D o not drive pin out with ham m er. This LIGHT TR U C K SE R V IC E M A N U A L STEERING C O L U M N S 3B4-37 b. Remove the felt washer, plastic washer and dust cap. D iscard the felt washer. 2. If the trunnion assemblies are to be replaced, proceed as follows: a. Remove the snap rings retaining the trunnion bushings in one of the yokes. b. Support the yoke on a bench vise and drive out one bushing by tapping on the opposite bushing using a soft drift and ham m er. c. Support the other side of the yoke and drive out the rem aining bushing as in Step b above. d. M ove the yoke on the trunnion as necessary to separate the upper and lower yokes. e. Remove the trunnion from the lower yoke as outlined in Steps a through d above. Remove and discard the seals. Assembly Installation NOTICE: See N O T IC E on page 1 o f this section regarding the fasteners referred to in steps 1, 3 and 4. 1. Install the interm ediate shaft assembly onto the steering shaft, aligning the flat on the shaft with the flat in the coupling. Install the pot jo in t clam p bolt and torque to specifications. 2. Lift the steering gear into position, guiding the flexible coupling bolts into the shaft flange holes. 3. Install the steering gear to fram e bolts and torque to specifications. 4. Install the flexible coupling to steering shaft flange bolt lockwashers and nuts. Check th at the coupling alignm ent pins are centered in the flange slots and then torque the coupling bolts to specifications. INTERMEDIATE STEERING SHAFT WITH UNIVERSAL JOINT COUPLINGS Removal (Fig. 3B4-63) 1. If the yoke trunnions were removed, reassemble as follows: a. Place the new trunnion into the lower yoke. b. Place new seals onto the trunnion and then press the new bushings into the yoke and over the trunnion hubs far enough to install the snap rings. c. Install the snap rings. d. Repeat Steps a through c to attach the upper yoke to the trunnion. 2. Reassemble the interm ediate shaft assembly as follows: a. Place the dust cap, plastic washer and a new felt seal over the shaft on the lower yoke assembly. b. Align the arrow on the lower yoke assembly shaft with the arrow on the upper yoke assembly tube and push the two assemblies together. c. Push the dust cap, plastic washer and felt washer into position on the lower end of the upper yoke assembly and bend the tangs of the dust cap down against the yoke tube. Installation N O T IC E : See N O T IC E on page 1 of this section regarding the fasteners referred to in steps 1, 3 and 4. 1. Set front wheels in straight ahead position. This can be done by driving the vehicle a short distance on a flat surface. 2. M ark upper universal jo in t yoke to steering shaft relationship and lower yoke to steering gear worm shaft relationship. 3. Remove both upper and lower universal yoke pinch bolts. 4. Rem ove steering gear to fram e bolts and lower the gear. It is not necessary to disconnect the pitm an arm from the steering gear pitm an shaft. 5. Remove the interm ediate steering shaft and universal joint assembly. 1. Align the m arks m ade at removal and assemble the interm ediate shaft lower yoke onto the steering gear wormshaft. Install the pinch bolt and torque to specifications. The pinch bolt m ust pass through the shaft undercut. If a new yoke was installed, the slit in the yoke should be in the 12 o’clock position. 2. Raise the steering gear into position while guiding the upper yoke assembly onto the steering shaft. The m arks on the coupling and steering shaft m ust align. I f a new yoke was installed, assemble the upper yoke to the steering shaft with the steering wheel in straight ahead position (gear m ust be on high point). 3. Install the steering gear to fram e bolts and torque Disassembly to specifications. 1. If the upper o r lower half o f the interm ediate 4. Install the upper yoke to steering shaft pinch bolt steering shaft is to be replaced, proceed as follows: and torque to specifications. a. W ith the shaft assembly on a bench, straighten the N O T IC E : The pinch bolt must pass through the shaft tangs on the dust cap. Separate the upper and lower portions of the shaft assembly. undercut, or dam age may occur to the components. LIGHT T R U C K SE R V IC E M A N U A L 3B4-38 STEERING C O L U M N S STEERING COLUMN UPPER BEARING-G AND P SERIES Standard Column Removal 1. Remove steering wheel as outlined in this section. 2. Rem ove directional signal cancelling cam. 3. Pry out upper bearing. Installation NOTICE: See N O T IC E on page 1 o f this section regarding the fasteners referred to in step 1. 2. Pry out the lower bearing assembly. Installation NOTICE: See N O T IC E not on page 1 of this section regarding fasteners referred to in step 2. 1. Place the new bearing over the end of the steering shaft and press into position in the column. 2. Install the preload spring and clam p and torque the clam p bolt nut to specifications. Refer to "Bearing A djustm ent" in "M aintenance and A djustm ent Section. Reinstall the interm ediate shaft and universal joint assembly as outlined under "Interm ediate Steering Shaft with Universal Joint Couplings - Installation". 1. Replace all com ponent parts in reverse order of TILT COLUMN BEARING HOUSING ASSEMBLY rem oval m aking sure th at directional switch is in neutral - G AND P SERIES position before installing steering wheel. Torque steering Removal (Column in Vehicle) wheel nut to specifications. 1. D isconnect the battery ground cable. Tilt Column 2. Remove the steering wheel as outlined under The upper bearings on the tilt colum n are spun into the "Steering Wheel - Removal". bearing housing assembly. I f the bearings indicate need of 3. Remove the directional signal switch as outlined replacement, the entire bearing housing m ust be replaced. under "D irectional Signal Switch - Rem oval". See "Tilt Steering C olum n - D isassembly and Assembly" for 4. Column Shift Models - Using a suitable size the correct replacem ent procedure. punch, drive out the shift lever pivot pin and remove the shift lever. STEERING COLUMN LOWER BEARING P 5. Install the tilt release lever and place the column in SERIES the full "up" position. Remove the tilt lever spring and Removal retainer using a screwdriver that just fits into the slot 1. Remove the interm ediate steering shaft and opening. Insert the screw driver into the slot, push in universal jo in t assembly as outlined earlier in this section. approxim ately 3/16", rotate clockwise approxim ately 1/8 Remove the preload spring clam p and spring from the end tu rn until the retainer ears align with the grooves in the o f the steering shaft. housing and remove the retainer and spring. LIGHT T R U C K SE R V IC E M A N U A L STEERING C O L U M N S 3B4-39 If the bearing housing support is being replaced, proceed as follows: 10. Remove the four bearing housing support screws and remove the support. Assembly NOTICE: See N O T IC E on page 1 of this section regarding the fasteners referred to in steps 3, 9 and 11. 1. Assemble the steering shaft as follows: a. Lubricate and assemble the centering spheres and preload spring. b. Install the spheres into the upper (short) shaft and rotate 90°. c. Install the lower shaft 90° to the upper shaft and over the centering spheres. Slowly straighten the shafts while compressing the preload spring. 2. Install the shaft assembly into the housing from the upper end. 3. Install the lower shaft to the pot joint coupling clamp. Install the coupling clamp bolt and torque to specifications. NOTICE: The coupling bolt m ust pass through the shaft undercut, or damage may occur to the components. 6. Remove the steering shaft bearing locknut using Socket J-22599. Rem ove the upper bearing race seat and race. 7. Remove the two bearing housing pivot pins using Tool J -2 1854. 8. Pull up on the tilt release lever (to disengage the lock shoes) and remove the bearing housing. If the bearing housing is being replaced or it is necessary to disassemble the bearing housing, proceed as follows: a. Press the upper and lower bearings out of the housing. b. Using Puller J-5822 and Slide H am m er J-2619, pull the bearing races from the housing. c. Remove the tilt release lever. d. Drive out the shoe release pivot pin using Tool J22635 or a suitable punch. Rem ove the lever spring and remove the wedge. e. Using a suitable size punch, drive out the lock shoe retaining pin. Remove the shoes and shoe springs. If the upper steering shaft, lower steering shaft, or centering spheres are being removed, proceed as follows: 9. To rem ove the steering shaft assembly through the upper end of the colum n. If it is necessary to disassemble the shaft, proceed as follows: a. To remove the lower steering shaft first disconnect the shaft at the pot jo in t coupling clamp. b. T u rn the upper shaft 90° to the lower shaft and slide the upper shaft and centering spheres from the lower shaft. c. R otate the centering spheres 90° and remove the centering spheres and preload spring from the upper shaft. Assemble the bearing housing as follows: a. Press the new upper and lower bearing races into the bearing housing. b. Lubricate and install the bearings into the bearing races. c. Place the lock shoe springs in position in the housing. Install each shoe in place and compress the spring until a suitable size straight punch can be used to hold the shoe in position (it may be necessary to acquire assistance to install the shoes). Once the shoes are in place, drive in the shoe retaining pin. d. Install the shoe release lever and drive in the pivot pin. e. Install the tilt release lever. f. Lubricate the shoes and release lever. 5. Install the bearing housing assembly to the support. Hold the tilt release lever in the "up" position until the shoes have fully engaged the support. Lubricate and install the bearing housing pivot pins. Press the pins in flush with the housing. 6. Place the housing in the full "up" position and then install tilt spring and retainer (tapered end of spring first). Push into the housing approxim ately 3/16" and rotate counterclockwise 1/8 turn. 7. Lubricate and install the upper bearing race, race seat and locknut. Tighten the locknut (using Socket J22599) to remove the lash and then carefully further tighten 1/16 to 1/8 of a turn (column m ust be in straight ahead position). 4. 8. Remove the tilt release lever. 9. Install the directional signal switch as outlined under "D irectional Signal Switch - Installation". LIGHT T R U C K SE R V IC E M A N U A L 3B4-40 STEERING C O L U M N S DIRECTIONAL SIGNAL SWITCH Fig. 3B4-67~Directional Signal Switch Fig. 3B4-69~Removing Wires from Connector 10. C olum n Shift M odels - Install the shift lever and pivot pin. 5. Pry the wiring harness protector out of the colum n retaining slots as shown in Figure 3B4-68. 6. M ark the location of each wire in the half-moon connector and then remove each individual wire from the connector using Tool J-22727 (Fig. 3B4-69). Insert the tool into the lower end of the connector and push in until the tool bottom s on the connector. Remove the tool and then pull the wire from the connector. 7. Remove the directional signal lever screw and remove the lever. 8. Push in on the hazard w arning light knob and then unscrew and remove the knob. 9. Tilt Columns Only a. A utom atic Transm ission M odels - Remove the P R N D L dial screws and remove the dial and indicator needle. Remove the cap and dial illum ination bulb from the housing cover. b. Unscrew and remove the tilt release lever. c. Assemble Tool J-22708 inside the directional signal housing cover; push in until the tangs lock inside the cover flange (Fig. 3B4-70). T urn the tool center screw clockwise to pull the cover from the housing. 11. Install the steering wheel "Steering W heel - Installation". as outlined under 12. Check electrical and m echanical functioning of column. DIRECTIONAL SIGNAL SWITCH If the directional signal switch m ust be replaced, the steering colum n does not have to be removed from the vehicle. Removal 1. Remove the steering wheel as outlined under "Steering W heel - Rem oval". 2. Rem ove the directional signal switch cancelling cam and spring. 3. Rem ove the colum n to instrum ent panel trim plate (if so equipped). 4. D isconnect the directional signal switch wiring harness at the half-m oon connector. J -2 2 7 0 8 Fig. 3B4-68--Removing Wiring Harness Protector Fig. 3B4-70--Removing Directional Signal Housing Cover LIGHT T R U C K SE R V IC E M A N U A L STEERING C O L U M N S 3B4-41 out the lower end of the shift lever housing and under the dash seal. 2. Place the directional signal switch in position and install the three m ounting screws; torque to 25 lbs. in. after screw head has been firmly seated. 3. Tilt Columns Onlya. Align the openings in the directional signal switch cover with the proper lever positions and tap the cover into place using a plastic ham m er. b. Install the tilt release lever. c. A utom atic Transm ission M odel - Install the P R N D L dial, pointer, dial illum ination bulb and cap. 4. Install the directional signal switch lever and hazard warning knob. 5. Bend the wire retaining tabs slightly outw ard on each wire in the wiring harness as shown in Figure 3B4-71; this will provide proper retention of the wire in the half­ moon connector. 10. Remove the three directional signal switch 6. Install each wire in its m arked location in the half­ m ounting screws and then carefully remove the switch moon connector. Push in until square p art of clip is flush assembly from the colum n while guiding the wiring harness with the bottom side of the connector. Connect the through the opening in the shift lever housing. directional signal switch wiring harness. Installation NOTICE: See N O T IC E on page 1 o f this section regarding the fasteners referred to in step 9. 7. Snap the wiring harness protector into the colum n retaining slots. 8. Install the directional signal cancelling cam and spring. 9. Install the steering wheel as outlined under 1. W rap the ends of the directional signal switch wires "Steering W heel - Installation". 10. Install the colum n to instrum ent panel trim plate w ith tape and then guide them through the opening at the (if so equipped). lower left hand side o f the bearing housing (tilt colum ns) STEERING COLUMN G AND P SERIES Removal 1. D isconnect the battery ground cable. 2. Colum n Shift M odels - D isconnect transm ission shifter rods at the lower end o f the column. 3. G Models - Rem ove the interm ediate steering shaft flange to flexible coupling bolts. P Models - Rem ove the interm ediate steering shaft upper universal yoke to steering shaft pinch bolt. M ark the coupling to shaft relationship. 4. Remove colum n clam p screw(s) on engine side of firewall, if equipped, and remove or slide the clam p down the column. 5. F rom inside the vehicle, remove the screws from the toe pan cover and slide the cover and seal up the column. 6. Remove the steering wheel as outlined under "Steering W heel-Rem oval", and reinstall the shaft n ut and washer. 7. All Colum ns - D isconnect the directional signal wiring harness. Standard Colum n with A utom atic Transm ission - D isconnect the conductor tube (for transm ission indicator) at the instrum ent panel. T ilt Colum n w ith A utom atic Transm ission D isconnect the single w ire at the fuse block and unclip it from the parking brake bracket. 8. Remove the cap screws from the colum n support bracket at the dash panel. 9. Carefully lower and then w ithdraw the colum n assembly, rotating so th at the shift levers clear the toe pan opening. Disassembly of Standard Column (Fig. 3B4-74) F o r floor shift transm ission models, om it Steps 4, 14, 15 and 16. 1. Rem ove the steering wheel nut and lock w asher and then slide the steering shaft assembly from the lower end of the column. 2. G M odels - Remove the lower bearing preload spring and clam p from the steering shaft. P M odels - Rem ove the lower bearing preload spring and clamp. 3. Rem ove the back-up lamp switch. 4. D rive out the shift lever pivot pin and remove the shift lever. 5. Remove the directional signal cancelling cam. Remove the directional signal switch lever. 6. Remove the colum n wiring harness cover. 7. Remove the directional signal switch screws. 8. R otate the directional signal switch housing counterclockwise and remove the housing from the column. The housing and switch cannot be fully removed from the colum n until the shift lever housing is removed. LIGHT T R U C K SE R V IC E M A N U A L 3B4-42 STEERING C O L U M N S STEERING SYSTEM M A N D A T O R Y REQ UIREM EN TS 1. Using a 50 lb. force applied to the steering wheel end of Shaft Lower Clamp Nut [ F ] must be tightened to the specified torque to give a compressed spring dimension ^T] of .50 ± .0 4 after assembly. 2. Flexible Coupling .2 5 0 /.3 7 5 . setup dimension Q [] must be NOTICE | This dimension must be held to prevent distortion of Flexible Coupling with resultant bind and harshness. 3. All Mast Jacket attachments [g ~| & | H | must be tightened to recommended torque. 4. Threaded portion of Steering Shaft [T ] must be completely free of lubricant after Mast Jacket assembly to maintain steering wheel clamping load and hub clearance. Fig. 3 B 4 -7 2 -S te e rin g Colum n Attachm ent-G Series ■A: \ , 9. Remove the plastic th ru st w asher assembly and then remove the shift lever housing (or extension housing) from STEERING SYSTEM M A N D A T O R Y REQ UIREM EN TS 1. Using a 50 lb. force applied to the steering wheel end of Shaft | A | , Lower Clamp Nut | B | must be tightened to the specified torque to give a compressed spring dimension [c~| of 1.26 ± .0 2 after assembly. 2. All Mast Jacket attachments |"pj & |"j~| must be tightened to recommended torque. 3. Threaded portion of Steering Shaft [~F~| must be completely free of lubricant after Mast Jacket | g | assembly to maintain steering wheel clamping load and hub clearance. Fig. 3B4-73--Steering Column Attachment - P Series LIG HT T R U C K SE R V IC E M A N U A L STEERING C OLUM NS 3B4-43 1. Upper Steering Shaft 13. Shift Tube Felt Washer 25. Turn Sigial Sw itch Screw 2. Shiff Housing.Sushing 14. Shift Tube Assembly 26. Turn Signal Switch 3. Bushing Seat 15. Shift Lever Spacer 27. Steering Shaft Upper Bearing 4. Mast Jacket 16. lst-Reverse Shift Lever 17. Adjusting Ring 28. Switch Contact Support 29. Turn Signal Housing 5. Column Cover 6. B ack-Up Lamp Sw itch Screw 18. Shaft Lower Bearing 7. Back-Up Lamp Switch 19. Lower Bearing Preload Spring 30. 31. Turn Signal Switch Lever Screw Turn Signal Sw itch Lever 8 . Toe Pan Seal Retainer 9. Toe Pan Seal 20. Preload Spring Clam p 32. R u b b e rin g 21. N u t and Lockwasher 33. Plastic 'hrust Washer 10. Adjusting Ring Clam p Screws 22. Steering Shaft N u t 34. Shift Lever Housing 1 1. N u t and Lockwasher 23. 24. Lockwasher Torn Signal C a n cellin g Cam 35. Shift Lever Pin 36. Shift Lever 12. Adjusting Ring Clam p Bolt Fig. 3B 4-74-S tan d ard Column-Typical G & P the colum n. 10. Separate the directional signal switch, switch control support assembly, directional signal housing and shift lever housing (or housing extension) assemblies. 11. Press the steering shaft upper bearing out of the switch contact support. 12. Remove the shift lever housing (or extension housing) seat and bushing from the upper end of the column. 13. Remove the bolt and screws from the adjusting ring clamp and remove the clamp, adjusting ring and lower bearing. Press the lower bearing out o f the adjusting ring. 14. 3-Speed C olum ns - Remove 1st-reverse shift lever and lever spacer. A utom atic C olum ns - Remove the selector plate clam ping ring screws (3). 15. Place the colum n upright on the floor, supporting it with two pieces o f wood. Place a block of wood on the upper end o f the shift tube. Press down on the shift lever with foot while tapping on the wood block to w ithdraw the tube from the colum n jacket. N O T IC E : In some tolerance stack-up cases it m ay be necessary to use a press. Be cireful not to dam age the tube or jacket. 16. Remove the felt seal from the shift tube. 17. Remove firewall clamp, to; pan seal and dash panel seals from the jacket. Assembly In the following assembly sequence use any general purpose lithium soap grease for lubricating those com ponents so indicated. 1. Install the dash panel seal, toe panel and firewall clamps over the end of the jacke;. 2. Lubricate all bearing surfaces on the shift tube. 3. Place the felt seal onto the shift tube (next to spring) and then place the shift tube in the jacket. 4. 3-Speed C olum ns - Temporarily install spacer, 1streverse shift lever and lower adjusting ring. Place a block of wood on top of the adjusting ring and tap until the shift tube bottom s. Remove adjusting ring, shift lever and spacer. LIGHT T R U C K SE R V IC E M A N U A L 3B4-44 S TEE RI NG C O L U M N S A utom atic Colum is - Align the three holes in the selector plate w ith the tlree holes in the jacket, position the clam ping ring and install the three screws. The shift tube spring retainer m ust be bottom ed against the jacket stops. 5. 3-Speed C olum is-L ubricate and install the spacer and 1st-reverse shift le/er (tang of lever tow ards top of column). 6. Install lower bearing in the adjusting ring and then install the adjusting rinj, clam p and screws. 7. Install the shift bver housing (or extension housing) seat and bushing to upper end o f housing. 8. T hread directiotial signal switch wiring harness through the switch ard lever (or extension) housings, lubricate the inner diameter o f the shift housing, and then place the shift lever (or extension) housing onto the upper end of the column. 9. Install the switch housing plastic w asher assembly. Press the upper bearing into the switch contact support. 10. Install the directional signal switch housing, contact support, bearing and switch and torque the switch screws to 25 lbs. in. 11. Install the column wiring harness cover and back­ up lamp switch. 12. Install the directional signal and gearshift levers. 13. A djust the shift tube as outlined under "Shifter Tube A djustm ent." 14. Loosely install the lower bearing preload spring and clamp. 15. Slide the steering shaft assembly up through the colum n assembly. Install the directional signal cancelling cam, steering shaft nut and lock washer. Disassembly O f T ilt Column (Fig. 3B4-75) 1. If the colum n is removed from the vehicle, place the colum n in a bench vise using H olding Fixtures J-22573 (Fig. 3B4-76). NOTICE: Clamping the colum n directly in a vise, could result in a damaged column. 2. Remove the directional signal switch as outlined under "D irectional Signal Sw itch-Rem oval". 3. Remove the lower steering shaft and pot joint assembly and lower bearing and adapter assembly as outlined under "Lower Bearing and A dapter-R em oval". 4. Colum n Shift Models - Using a suitable size punch, drive out the shift lever pivot pin and remove the shift lever. 5. Install the tilt release lever and place the colum n in the full "up" position. Remove the tilt lever spring and retainer using a screwdriver th a t ju st fits into the slot opening (Fig. 3B4-77). Insert the screwdriver clockwise approxim ately 1/8 tu rn until the retainer ears align w ith the grooves in the housing and rem ove the retainer and spring. 6. Rem ove the steering shaft bearing locknut using socket J-22599. Remove the upper bearing race seat and race. 7. Remove the two bearing housing pivot pins using Tool J-21854 (Fig. 3B4-78). 8. Pull up on the tilt release lever (to disengage the lock shoes) and remove the bearing housing. If it is necessary to disassemble the bearing housing, proceed as follows: A a. Press the upper and lower bearings out of the housing. b. Using Puller J-5822 and Slide H am m er J-2619 pull the bearing races from the housing (Fig. 3B4-79). c. Remove the tilt release lever. d. Drive out the shoe release lever pivot pin using Tool J-22635 or a suitable punch (Fig. 3B4-80). Remove the lever spring and remove the wedge. e. Using a suitable size punch, drive out the lock shoe retaining pin. Remove the shoes and shoe springs. 9. Remove the steering shaft assembly through the upper end of the column. If it is necessary to disassemble the shaft proceed as follows: a. T urn the upper shaft 90° to the lower shaft and slide the upper shaft and centering spheres from the lower shaft. b. R otate the centering spheres 90° and remove the center spheres and preload spring from the upper shaft. 10. Remove the four bearing housing support screws and remove the support. Colum n Shift Models - If the shift tube index plate m ust be removed, remove the two retaining screws and remove the plate. 11. Remove the shift tube retaining ring with a screwdriver (Fig. 3B4-81). Remove the th ru st washer. 12. Remove the neutral-safety or back-up lamp switch screws and remove the switch. 13. Rework Shift Tube Removing Tool J-22551 by removing 1/2" from the pilot end of the tool (Fig. 3B4-82). This allows the shift tube to be pushed further out of the housing and will not affect the use of the tool on other columns. 14. Remove the shift tube assembly using Tool J-22551 (Fig. 3B4-83). Insert the hooked end of the tool into the notch in the shift tube just below the shift lever housing key. Pilot the sleeve over the threaded end of the tool and into the upper end of the shift tube. Force the shift tube out of the housing by turning the n ut onto the tool. If the shift tube is not completely free when the n u t is bottom ed on the threads, complete the removal by hand. NOTICE: D o not ham m er or pull on the shift tube during removal. On colum n shift models, guide the lower shift lever through the slotted opening in the colum n to prevent dam age to the tube or column. 15. Remove the lock plate by sliding out of the colum n notches, tipping the plate dow nw ard tow ard the housing (to compress the wave washer) and then removing as shown in Figure 3B4-84. Remove the wave washer. 16. Remove the shift lever housing. 17. Colum n Shift Models - Remove the shift lever spring by winding the spring up w ith pliers. 18. If necessary, remove the dash panel seal, m ounting plate and the instrum ent panel seal from the colum n jacket. Assembly of T ilt Column W hen installation grease. 1. instrum ent lubricating com ponents during the following sequence, use any general purpose lithium soap Install the dash panel seal, m ounting plate and the panel seal on the column. COVER SHAFT ASSY. ----- RACE WEDGE SHAFT RACE SCREW (3) SPRING SWITCH ASSY. —» Fig. 3B4-75—Tilt Steering PIN DOWEL ' / SHOEH O U S IN G ----- HO USING / ASSY. BEARING \ BUMPER (3) SHAFT ASSY. STEERING BEARING ASSY \ RETAINER _ SPHERE CENTERING (2) SHAFT JACKET ASSY.- JACKET PROTECTOR WIRE SUPPORT ASSY. SPRING ( 2 ) - . \ Column-G SPRING RELEASE, PIN RELEASE— - o \ SHOE RELEASE----- * BEARING ASSY. — ^ YOKE INSTRU. PANEL OPENING C O V E R -, U * * \ SUPPORT ( 2 ) P,N PIVOT TUBE ASSY. SHIFT (2 ) ^ BOWL ASSY. SPRING TILT SCREW DASH SEAL SCREW (4) SPRING ■CLIP JACKET DASH SEAL RETAINER '-PLATE & P \ RETAINER THRUST WASHER \ PLATE LOCK BOWL "* LEVER ADAPTER RETAINER BEARING STEERING COLUMNS WAVE WASHER 3B4-45 3B4-46 STEERING C O L U M N S Fig. 3 B 4 -7 6 -S e c u rin g Colum n w ith J -2 2 5 7 3 2. C olum n Shift M odels - Press a new shift lever spring into the shift lever housing. 3. Slide the shift lever housing over the upper end of the column. 4. Place the wave w asher and lock plate in position. W ork the lock plate into the notches by tipping the plate tow ard the housing (com pressing the wave washer) at the open side o f the colum n. L ubricate the lock plate and upper end of the shift tube. 5. Carefully install the shift tube into the lower end of the column (m ake sure the foam seal is at lower end of the shift tube). Align the keyway in the tube with the key in the shift lever housing and com plete installation o f the shift tube using Tool J-22549 (Fig. 3B4-85). The shift lever housing key m ust bottom in the shift tube slot to be fully installed. Remove Tool J-22549 from the colum n. Lubricate and push foam seal in flush with colum n housing. NOTICE: D o N ot ham m er or force the tube when installing in the colum n, or dam age could occur to the components. 6. Pull up on the shift lever housing (to compress the wave washer) and install the thrust washer and retaining ring. Be sure the ring is seated in both slots of the shift tube. 7. Lubricate the I.D . of the bearing housing support and install the support, aligning the bolt holes in the support w ith the bolt holes in the lock plate. Install the four support screws and torque to 45 in. lbs. 8. Assemble the steering shaft as follows: a. Lubricate and assemble the centering spheres and preload spring. b. Install the spheres into the upper (short) shaft and rotate 90°. c. Install the lower shaft 90° to the upper shaft and over the centering spheres. Slowly straighten the shafts while compressing the preload spring. 9. Install the shaft assembly into the housing from the upper end. 10. Install the lower bearing and adapter, bearing reinforcement, wire clip, pot joint coupling and lower shaft as described under "Lower Bearing Installation". STEERING SHAFT BEARING LO CKNUT TILT LEVER SPR IN G RETAINER Fig. 3B4-77-Removing Tilt Spring and Retainer LIGHT TR U C K SE R V IC E M A N U A L STEERING C O L U M N S 3B4-47 1 /1 6 ” 4 5 ° CHA M FER R E M O VE DOTTED P O R T IO N Fig. 3B 4 -8 0 ~ R e m o v in g Release Lever Pivot Pin 11. Assemble the bearing housing as follows: a. Press the new upper and lower bearing races into the bearing housing. b. Lubricate and install the bearings into the bearing races. c. Place the lock shoe springs in position in the housing. Install each shoe in place and com press the spring until a suitable size straight punch can be used to hold the shoes in position (it m ay be necessary to acquire assistance to install the shoes). Once the shoes are in place, drive in the shoe retaining pin. d. Install the shoe release lever and drive in the pivot pin. e. Install the tilt release lever. f. Lubricate the shoes and release lever. 12. Install the bearing housing assembly to the support. H old the tilt release lever in the "up" position until the shoes have fully engaged the support. Lubricate and install the bearing housing pivot pins. Press the pins in flush w ith the housing. Fig. 3 B 4 -8 2 -R e v is e d Shift Tube Removing Tool J -2 2 5 5 1 13. Place the housing in the full "up" position and then install tilt spring and retainer (tapered end of spring first). Push into the housing approxim ately 3/16" and rotate counter clockwise 1/8 turn. 14. Lubricate and install the upper bearing upper race, race seat and locknut. Tighten the locknut (using Socket J-22549) to remove the lash and then further tighten 1/16 to 1/8 of a turn (colum n m ust be in straight ahead position). 15. Remove the tilt release lever. 16. Install the directional signal switch as outlined under "D irectional Signal Sw itch-Installation". 17. C olum n Shift M odels - Install the shift lever and pivot pin. 18. Install the neutral-safety or back-up lam p switch. 19. Remove the colum n from the bench vise. HOOK ENDOF TOOL SLOT IN SHIFT TUBE Fig. 3B4-81~Removing Shift Tube Retaining Ring Fig. 3B4-83--Removing Shift Tube Assembly LIGHT T R U C K SE R V IC E M A N U A L 3B4-48 STEERING C O L U M N S 5. Loosely install the colum n dash bracket and screws. 6. Push the column down until the steering shaft flange bottom s on the plastic spacers on the flexible coupling and then torque the dash bracket screws. 7. Remove the plastic spacer from the alignm ent pins using a wire hook. Check the flexible coupling to steering shaft flange clearance (.25" to .325"), if not within specifications, the dash bracket screws m ust be loosened and the colum n raised or lowered as required. Retorque the bracket screws. The alignm ent pin plastic spacers m ust be removed before the vehicle can be driven. 8. Push the toe pan seal to the toe pan, install and torque the m ounting screws. Fig. 3 B 4 -8 4 -R e m o v in g Lock Plate Assem bly COLUMN INSTALLATION Mandatory Installation Sequence G Series NOTICE: See N O T IC E on page 1 o f this section regarding the fasteners referred to in steps 3 and 10. 1. A djust the colum n lower bearing preload by applying a force on the steering wheel end of the steering shaft (A). Position the spring and clamp to m aintain the dimension as detailed under "M aintenance and A djustm ents. 2. Install the plastic spacers onto the flexible coupling alignm ent pins. 3. From inside the vehicle, carefully insert the lower end of the colum n through the toe pan opening guiding the steering shaft flange onto the flexible coupling. Install and torque the glange to coupling bolts. 4. Locate the index slot in the colum n jacket w ith the protrusion on the clutch and brake pedal support. Fig. 3B4-85~lnstalling Shift Pin Tube 9. All C olum ns-C onnect the directional signal switch wiring harness. A utom atic Colum ns-Connect the conductor tube (for transm ission indicator) to the instrum ent panel. See Fig. 3B4-87. 10. Install the steering wheel as outlined under "Steering W heel Installation". 11. Connect the transmission linkage. 12. Connect the battery ground cable. Mandatory Sequence P Series NOTICE: See N O T IC E note on page 1 of this section regarding the fasteners referred to in steps 1, 2, 3 and 10. 1. A pplying 50 lbs. force on the steering wheel end of the steering shaft, adjust the lower bearing preload to allow steering shaft end play as indicated in "M aintenance and A djustm ents". Tighten the shaft clam p on pot joint bolt to specifications. 2. From the passenger side of the dash panel, carefully insert the lower end of the steering colum n through the toe panel opening. G uide the steering shaft into the universal yoke, lining up the m arks made at removal. Install the yoke pinch bolt and torque to specifications. The pinch bolt m ust pass through the shaft undercut. 3. Position and attach the lower clamp m ounting bracket to the firewall. Locate the steering column protrussions against the toe pan bracket while at the same time, aligning protrusion in brake and clutch pedal support with index slot in the steering column, as shown in Figure 3B4-87. Install the colum n to bracket clam p and torque the clam p bolt to specifications. The toe pan bracket m ust not override the protrusions on the steering column. 4. Position the steering colum n to dhas panel bracket, install the attaching bolts and torque to specifications. 5. If plastic spacers were used on the flexible coupling alignm ent pins, remove the spacers after all bolts have been properly torqued. 6. Install the seal at the toe pan and then install the toe pan bracket screws; torque to specifications. 7. Install the dash panel trim plate (if so equipped). 8. Connect the transm ission shift linkage on colum n shift models. LIGHT TR U C K S E R V IC E M A N U A L STEERING C O L U M N S 3B4-49 STEERING SYSTEM M A N D A T O R Y REQUIREMENTS 1. Using a 50 lb. force app lie d to the steering w heel end of Shaft j A | , Lower Clam p Nut |~B~] must be tightened to the specified torque to give a compressed spring dimension | C | of .5 0 ± . 0 4 2. a fte r assembly. Flexible Coupling [~D~| setup dimension (~E~| must be .2 5 0 /.3 7 5 . | NOTICE This dimension must be held to prevent distortion o f Flexible Coupling w ith resultant bind and 3. harshness. All M ast Jacket attachm ents [ g ~] & (~H~| must be tightened to recommended torque. 4. Threaded portion o f Steering Shaft j J | must be com pletely free o f lubricant a fte r M ast Jacket | K | assembly to m ain tain steering wheel clam ping load and hub clearance. Fig. 3B4-86~M andatory Sequence For Installation Of G Series Column 9. harness. All Colum ns - Connect the directional signal wiring Standard C olum n with A utom atic Transm ission Connect the conductor tube (for transm ission indicator) at the instrum ent panel (Fig. 3B4-88). 10. Install steering wheel as outlined under "Steering W heel-Installation". 11. Connect battery ground cable. Fig. 3B4-87~Conductor Tube For Automatic Transmission Indicator LIGHT TR U C K SE R V IC E M A N U A L A 3B4-50 STEERING C O L U M N S STEERING SYSTEM M A N D A T O R Y REQUIREMENTS 1. Using a 50 lb. force app lie d to the steering w heel end of Shaft | A | f Low er Clam p Nut |~B~| must be tightened to the specified torque to give a compressed spring dimension | C | of 1.26 ± .0 2 a fte r assembly. 2. All M ast Jacket attachm ents |~p] & | E | must be tightened to recomm ended torque. 3. Threaded portion of Steering Shaft |~F~[ must be com pletely free of lubricant a fte r M ast Jacket JG | assembly to m ain tain steering w heel clam ping load and hub clearance. Fig. 3B4-88~M andatory Sequence For Installation of P Series Column LIGHT T R U C K SE R V IC E M A N U A L STEERING C O L U M N S 3B4-51 SPECIFICATIONS STEERING GEAR RATIOS Power Manual V e h icle Ge a r R a tio O v e r a ll R a tio Ge a r R a tio O v e r a ll R a tio G 10-20 24:1 29.4:1 to 36.7:1 14:1 21.4:1 to 26.7:1 G30 24:1 29.4:1 to 36.4:1 14:1 21.4:1 to 26.5:1 P20-30 — — 17.5:1 21.2:1 to 25.7:1 M otor Home - - 14:1 16.0:1 to 21.9:1 C10 24:1 29.1:1 to 37.0:1 16:1 to 13:1 16.9:1 to 20.2:1 C20-30 24:1 29.4:1 to 36.3:1 16:1 to 13:1 17.2:1 to 20.6:1 — — 16:1 to 13:1 13.2:1 to 17.2:1 K 10-20 MANUAL STEERING GEAR Components A ll C-G POWER STEERING PUMP PRESSURES Pressure V e h ic le 1200- 1300 psi C10-30 T hrust Bearing Preload 5 to 8 lbs. in. Adjuster Plug Lock N ut 85 lbs. ft. Over Center Preload 4 to 10 lbs. in .* Over Center Lock N ut 25 lbs. ft. Total Steering Gear Preload 18 lbs. in. Max. G 10-20-30 w /o H ydroboost 900 - 1000 psi G30 w ith Hydroboost 1350 - 1450 psi P10-30 1200- 1300 psi M otor Home & K 1350- 1450 psi * ln excess o f th ru st bearing preload. Fig. 3B4~Specs LIGHT TR U C K SE R V IC E M A N U A L 3B4-52 STEERING C O L U M N S SPECIAL TOOLS 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. J-6632 J-5504 J-23073 J-23072 J 5176 J-5822 J-8433 J-21854 J-23653 J-5421 J-5860 J-21239 J-2927 J 1614 J-7539 J-7624 J-4245 J-22670 Pitman A rm Puller Pitman A rm Puller Shift Tube Installer Shift Tube Remover Oil Pressure Gauge W ormshaft Bearing Cup Remover Pump Pulley Remover (Cast Pulley) C olum n Pivot Pin Remover Lock Plate Compressor Thermometer Torque Wrench Adapter Pump Pulley Remover (Stamper Pulley) Steering Wheel Puller Sector Shaft Bushing Remover Ball Retainer Spanner Wrench #23 Internal Pliers Pump Shaft Seal Installer 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. J-6222 J-23600 J-8947 J-5755 J 2619 J-8092 J-6278 J-6278-2 J-7079-2 J-8524-1 J-8524-2 J-6219 J-22407 J-8937 J 6217 J-23980 Shaft Seal Protector Belt Tension Gauge Rack-Piston Seal Compressor Wormshaft Bearing Race Installer Slide Hammer Handle Pitman Shaft Bearing Remover Pitman Shaft Bearing Installer Handle Adjuster Plug Bearing Installer Adjuster Plug Bearing Remover Pitman Shaft Seal Installer Pitman Shaft Bearing Installer Ball Seal Remover Connector Seat Installer Steering Column Electrical Analyzer Torque Wrenches Fig. 3B-1 ST--Special Tools C and K Models LIGHT T R U C K S E R V IC E M A N U A L STEERING C O L U M N S 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. J-6632 J-5504 J-5176 J-5822 J-5860 J-22670 J-6222 J-9226 J-7576 J-21239 J-2927 J-1614 J-7539 J-7624 J-4245 J-23600 J-5755 J-2619 Pitman A rm Puller Pitman A rm Puller Pressure Gauge W orm shaft Bearing Cup Puller Torque Wrench Adapter Pump S haft Seal Installer Shaft Seal P rotector Pitman Shaft Bushing Replacer Rack-Piston Seal Compressor Pump Pulley Remover Steering Wheel Puller Sector Shaft Bushing Remover Ball Retainer Spanner Wrench #23 Internal Pliers Belt Tension Gauge Wormshaft Bearing Cup Installer Slide Hammer J-6278 J-6278-2 J-7079-2 J-8524-1 J-8524-2 J-6219 J-6217 J-5421 J-22407 J-22727 J-22708 J-22573 J-22599 J-21854 J-22551 J-22549 3B4-53 Pitman Shaft Bearing Remover Pitman Shaft Bearing Installer Drive Handle A djuster Plug Bearing Installer A djuster Plug Bearing Remover Pitman Shaft Seal Installer Connector Seat Installer Therm om eter Pitman Shaft Bearing Installer Term inal Remover T urn Signal Cover Remover Steering Column H olding Fixture Lock N ut Socket Pivot Pin Remover S h ift Tube Remover S h ift Tube Installer Torque Wrenches Fig. 3B-2ST-Special Tools G and P Models LIGHT T R U C K SE R V IC E M A N U A L „••; r ? ■’-f i W & K 5 3 ' i ■ FRONT SUSPENSION 3C-1 SECTION 3C FRONT SUSPENSION The following notice applies to one or more steps in the assembly procedure of components in this portion of the m anual as indicated at appropriate locations by the terminology "See N otice on page 1 of this section". N O TIC E This fastener is an im portant attaching part in th at it could affect the perform ance of vital components and systems, an d /o r could result in m ajor repair expense. It must be replaced with one of the same part num ber or with an equivalent part if replacem ent becomes necessary. Do not use a replacem ent part of lesser quality or substitute design. Torque values m ust be used as specified during reassembly to assure proper retention of this part. CONTENTS OF THIS SECTION Front Suspension (C -G -P S e rie s)................................................................. 3C-2 Front Suspension (K -S eries).......................................................................... 3C-23 FRONT SUSPENSION, TWO-WHEEL DRIVE INDEX G eneral D escription............................................................ 3C-2 M aintenance and A d ju stm e n ts....................................... .3C-3 D iagnosis............................................................................... .3C-4 Com ponent Parts R eplacem ent....................................... 3C-14 W heel Hubs, B earings................................................... 3C-14 Shock A b so rb e r.............................................................. 3C-15 S ta b iliz e r........................................................................... 3C-15 Coil S p rin g ....................................................................... 3C-15 Upper Control Arm S h a ft................... Lower Control A rm S haft. Upper Control A rm ............ Lower Control A rm ............ Ball Jo in t............................... Steering K nuckle................ Suspension Unit Specifications Special Tools. 3C-16 3C-16 3C-17 3C-18 3C-20 3C-21 3C-22 3C-40 3C-41 LIGHT TRUCK SERVICE MANUAL 3C-2 FRONT SUSPENSION GENERAL DESCRIPTION C-G-P Series The C -G -P Series trucks incorporate an independent coil spring front suspension system, as shown in Figures 3C1 and 3C-2. The control arm s are of unequal length (S.L.A . Type). This suspension system consists of upper and lower control arm s pivoting on steel threaded or rubber bushings on upper and lower control arm shafts. The lower control arm s are attached to the crossm em ber. The upper control arm s are attached to a fram e bracket. These control arm s are connected to the steering knuckle through pivoting ball joints. A coil spring is located between the lower control arm and a formed seat in the suspension crossmember, thus the lower control arm is the load carrying member. Double acting shock absorbers are also attached to the lower control arm s and connect with the fram e to the rear on the upper end. The front wheel bearings are tapered roller type and are used on all models. Fig. 3C-1 --Front Suspension, C-P Series LIGHT TRUCK SERVICE MANUAL FRONT SUSPENSION 3C-3 Fig. 3C-2--Front Suspension - G-Typical MAINTENANCE AND ADJUSTMENTS NOTICE: See N O T IC E on page 1 of this section regarding the fasteners referred to in the m aintenance and adjustm ent procedures below. WHEEL BEARINGS-CHECK ADJUSTMENT NOTICE: Tapered roller bearings are used on all series vehicles and they have a slightly loose feel when properly adjusted. A design feature of front wheel taper roller bearings is th a t they m ust N E V E R be preloaded. D am age can result by the steady thrust on roller ends which comes from preloading. 1. Raise vehicle and support at front lower control arm . 2. Spin wheel to check for unusual noise or roughness. 3. If bearings are noisy, tight, or excessively loose, they should be cleaned, inspected and relubricated prior to adjustm ent. If it is necessary to inspect bearings, see "W heel H ubs, B earings" under "C om ponent Parts R eplacem ent." To check for tight or loose bearings, grip the tire at the top and bottom and move the wheel assembly in and out on the spindle. M easure movement of hub assembly. If movement is less than .025 mm (.001 ") or greater than .127 mm (.0 0 5 " ), ad ju st bearings per ad ju stm en t procedure. LIGHT TRUCK SERVICE MANUAL 3C-4 FRONT SUSPENSION ADJUSTMENT OF WHEEL BEARINGS (FIG. 3C-3) 1. 2. 3. 4. 3. BACK OFF NUT UNTIL JUST LOOSE POSITION. TIGHTEN THE NUT TO 12 FT. LBS. FULLY SEAT OVERCOMES ANY BURRS O N THREADS. HAND "SNU GTHE NUT i. LOOSEN NUT UNTIL EITHER HOLE IN THE SPINDLE LINES UP WITH A SLOT IN THE NUT-THEN INSERT COTTER PIN. NOTE: BEND ENDS OF COTTER PIN AG A IN ST NUT, CUT OFF EXTRA LENGTH TO PREVENT INTERFERENCE W ITH DUST CAP Remove hub cap or wheel disc from wheel. Remove dust cap from hub. Remove cotter pin from spindle and spindle nut. Tighten the spindle nut to 16 N-m (12 ft. lbs.) while turning the wheel assembly forward by hand to fully seat the bearings. This will remove any grease or burrs which could cause excessive wheel bearing play later. See Fig. 3C-3. 5. Back off the nut to the "just loose" position. 6. Hand tighten the spindle nut. Loosen spindle nut until either hole in the spindle lines up with a slot in the nut. (N ot more than 1/2 flat). 7. Install new cotter pin. Bend the ends of the cotter pin against nut, cut off extra length to ensure ends will not interfere with the dust cap. 8. M easure the looseness in the hub assembly. There will be from .025 mm (.001) to .127 mm (.005 inches) end play when properly adjusted. 9. Install dust cap on hub. 10. Replace the wheel cover or hub cap. 11. Lower vehicle to floor. 12. Perform the same operation for each front wheel. W H EN THE BEARING IS PROPERLY ADJUSTED THERE WILL BE FROM . 0 0 1 - 0 0 5 INCHES END-PLAY (LOOSENESS). Fig. 3C-3--Wheel Bearing Adjustment DIAGNOSIS SHOCK ABSORBER DIAGNOSIS ON VEHICLE CHECKS (Follow the Procedures O utlined Below in the O rder Indicated). Preliminary Inspection and Ride Test: Tire Pressure Check tire pressure com pare to vehicle specifications and ad ju st as required. Poor vehicle control and ride com plaints are caused in m any cases by im proper tire inflation. Special Suspension E quipm ent C heck Service P arts Identification S tick er for any special suspension equipm ent; such as, a heavy duty suspen­ sion. Vehicles equipped with this type of option have a somewhat stiffer or harsh ride, and this should be kept in mind during the following tests. If com plaint about stiffness should occur while vehicle is still new (under 5,000 miles) (8 LIGHT TRUCK SERVICE MANUAL 000 km), owner should be advised to have ride rechecked after 7,000 to 8,000 miles (11 200 to 12 800 km). Vehicle Load Conditions N ote any exceptional load conditions under which the owner normally operates the vehicle; such as, large tool boxes full of tools, pick up bed full etc. If exceptional loading is apparent, check the distribution of this weight. N ote if it is all toward one side of the vehicle or at the extreme rear of the vehicle. Reposition load as required to obtain a more uniform weight distribution. Check Vehicle Ride a n d H a n d lin g A fter completing previous checks, ride vehicle with owner to determ ine if problem has been corrected or to definitely establish type of problem th a t still exists. If problem still exists (poor handling, bottom ing, noise, ride sway, etc.), proceed. Inspecting an d Testing th e Shocks Three procedures are included in this step. T het are (a) Bounce Test, (b) Inspecting Shock M ountings for Noise FRONT SUSPENSION 3C-5 .......... HARD STEERING Probable Remedy Probable Cause a. Ball jo ints and steering linkage ne ed lu bric ation a. Lubricate ball jo in ts and linkage b. Low or uneven fron t tire pressure b. Inflate tires to the pro p e r re co m m e n d e d pressure c. Pow er steering partially or n o t operativ e c. Check p o w e r steering c o m p o n e n t s for pro p e r o p e ratio n d. Steering gear no t pro pe rly adjusted d. Adjust steering gear e. Incorr ect front wheel alig nm en t (m anu al steering) e. Check and align f ron t suspension POOR DIRECTIONAL STABILITY a. Ball jo in ts and steering linkage need lubric ation a. L ubricate at p ro p e r intervals Inflate tires to the p ro p e r re co m m e n d e d pressure b. Low or uneven f ro n t or rear tire pressure b. c. Loose wheel bearings c. Adjust wheel bearings d. Steering Gear n o t on high p o in t d. Adjust steering gear e. In correct front wheel alignm ent (caster) e. Check and align front suspension f. Broken springs f. Replace springs g- M alfunctioning shock a bsorber. g. Diagnose shock absorbers. h. Broken stabilizer b a r, or missing link h. Replace stabilizer or link FRONT WHEEL SHIMMY (SM O O T H R O A D SH A K E ) a. Tire a nd wheel o u t o f bala nce, or o u t o f rou nd a. Balance tires, c hec k run -ou t Adjust wheel bearings b. Worn or loose wheel bearings b. c. W orn tie rod ends c. Replace tie rod end d. Worn ball joints d. Replace ball j oin ts e. M alfunctioning shock a b sorber e. Diagnose sh ock a bsorbers VEHICLE PULLS TO ONE SIDE (N O BR A K IN G ACT IO N ) a. L ow or uneven tire pressure a. Inflate tires to the p ro p e r r e com m e nd e d pressure b. F r o n t or rear bra k e dragging b. Adjust bra kes c. Broken or sagging f ro n t spring c. Replace spring d. Incorrect f ro n t wheel a lignm ent (C a m b e r) d. Check and align fro nt suspension EXCESSIVE PLAY IN STEERING a. Incorrect steering gear a d ju s tm e n t a. Adjust steering gear b. Worn steering gear p arts b. Overhaul Gear Fig. 3C-4--Front Suspension Diagnosis Chart A (Looseness) and (c) M anually O perating Shocks to Determine if Shocks are W eak, Leaking H ydraulic Fluid, an d/or if Shocks have an Internal Noise Condition. Test procedures (b) and (c) require vehicle to be on a hoist that supports wheels or rear axle housing and front lower control arms. LIGHT TRUCK SERVICE MANUAL 3C-6 FRONT SUSPENSION NOISE IN FRONT END Probable Cause a. Probable Remedy Ball joints a nd steering linkage need lubrication a. Lubricate at r e c o m m e n d e d intervals h. Shock a b sorb er loose or bushings worn b. T ighten bolts a n d /o r replace bushings c. Worn co n tro l arm bushings c. Replace bushings d. Worn tie rod ends d. Replace tie rod ends c. Worn or loose wheel bearings e. Adjust or replace wheel bearings f. Loose stabilizer bar f. Tighten all stabilizer bar a tt a c h m e n t s g- Loose wheel nuts fi­ T ig hten the wheel nuts to p ro p e r to r q u e h. Spring im pro perly positio ned ll. Reposition i. Loose suspension bolts i. T o rque to specifications or replace a. Tire and wheel o u t 'of balance a. Balance wheels b. Tire and wheel ou t o f round b. Replace tire c. Blister o r b u m p on tire c. Replace tire d. Im p ro p er sh ock a b so rb er action d. Replace shock absorber WHEEL TRAMP EXCESSIVE OR UNEVEN TIRE WEAR a. Underinflated or overin flated tires a. Inflate tire to p ro p e r re co m m e n d e d pressure b. Im pro per toe-in b. Adjust toe-in c. Wheels out o f b alance e. Balance wheels d. Hard Driving d. Instruct driver c. Over loaded vehicle e. Instruct driver SCUFFED TIRES a. Toe-in incorrect a. Adjust toe-in to specifications b. Excessive speed on turns b. Advise driver e. Tires im p ro p e rly inflated c. Inflate tires to pro pe r r e c o m m e n d e d pressure d. Suspension arm b e n t o r tw isted d. Replace arm S i 1 ' ■>' vxfc* t »ftt : * " CUPPED TIRES a. Fron t shock a bsorb ers defective a. Replace sh ock absorbers b. Worn ball jo ints b. Replace ball join ts c. Wheel bearings incorrectly adju sted or worn c. Adjust or replace wheel bearings d. Wheel and tire o u t o f balance d. Balance wheel and tire c. Excessive tire or wheel ru nou t e. C o m p en s ate for run out Fig. 3C-5--Front Suspension D iagnosis C hart B Bounce Test This is only a com parison type test to help locate the suspected shock or noise condition before proceeding. Test each front and rear shock by bouncing each corner of the vehicle. This can usually be done by lifting up and pushing down on the end of the bum per near each corner of the vehicle u ntil m axim um m ovem ent up and down is reached. Then let go of bum per and observe if the up and LIGHT TRUCK SERVICE MANUAL down motion stops very quickly. If up and down motion continues longer at one corner when com pared to opposite corner (example, both front shocks), the one having the longer up and down m otion may be suspect. Do N ot com pare front to rear. If com plaint is noise, this test should help to locate the suspected area. FRONT SUSPENSION 3C-7 NOISE IN FRONT END Probable Cause Probable Remedy a. Ball joints and steering linkage need lubrication a. Lubricate at re co m m e n d e d intervals b. S l u v k a bso rber loose or bushings worn b. T ig hten bolts a n d /o r replace bushings c. Worn c ontrol arm bushings c. Replace bushings d. Worn tie rod ends d. Replace tie rod ends 0. Worn or loose wheel bearings e. Adjust or replace wheel bearings T ighten all sta b ili/e r bar a tta c h m e n ts f. Loose stab ili/er bar f. (T P- Loose wheel nuts ti­ T ighten the wheel nuts to proper torqu e h. Spring im properly p ositioned ll. R eposition i. Loose suspension holts i. T orq ue to specificatio ns or replace W HEEL TRAM P a. Tire and wheel o u t o f balance a. Balance wheels b. Tire and wheel out o f r ou nd b. Replace tire c. Blister or b u m p on tire c. Replace tire d. I m p ro p er shock a b sorb er action d. Replace shock absorber EX C ESSIV E OR UNEVEN TIR E W EAR a. Un derinflated or overin flated tires a. Inflate tire to p r o p e r re co m m e n d e d pressure b. Im p ro p er toe-in b. Adjust toe-in c. Wheels tint o f balance c. Balance wheels d. Hard Driving d. Instruct driver e. Over loaded vehicle e. Instruct driver SCU FFED T IR E S a. Toe-in incorrect a. Adjust toe-in to specifications b. Excessive speed on turns b. Advise driver e. Tires im prop e rly inflated c. Inflate tires to prope r re co m m e n d e d pressure d. S uspension arm b e nt o r twisted d. Replace arm CUPPED T IR E S a. Fro n t sh ock absorbers defective a. Replace shock absorbers b. Worn ball jo ints b. Replace ball jo in ts c. Wheel bearings incorrectly a d juste d or worn c. Adjust or replace wheel bearings d. Wheel and tire out o f b alance d Balance wheel and tire c. Excessive tire or wheel run out e. C o m p en s ate for runo ut Fig. 3C-6--Front Suspension Diagnosis Chart C Inspecting Shock Mountings If noisy an d /o r loose shock m ountings are suspected, place vehicle on hoist th a t supports wheels and check all mountings for the following conditions: If no apparent defects are noted in this step but noise condition still exists when vehicle is bounced up and down, proceed. Inspecting Shocks for Leaks and (1 ^Vorn or defective grom m ets (2XvOOse mounting nuts Manually Operating Shocks (3Possible interference condition This procedure is sub-divided into two general areas, (1) Inspecting Shocks for Loss of H ydraulic Fluid and (2) (4 ^ u m p stops missing LIGHT TRUCK SERVICE MANUAL 3C-8 FRONT SUSPENSION BALL JOINT DIAGNOSTIC PROCEDURE Fig. 3C-7--Ball Joint Diagnostic Procedure M anually O perating Shock. It should aid the technician to localize defective shocks caused by internal noise in the shock, weak, leaking, etc. 1. Inspecting Shocks for Possible Loss o f H ydraulic Fluid. LIGHT TRUCK SERVICE MANUAL (a) Disconnect each shock lower mounting as required and pull down on the shock until it is fully extended. (b) Inspect shocks for leaks in seal cover area. Shock fluid is a very thin hydraulic fluid and has a characteristic odor and dark brown tint (Figure 3C-8). FRONT SUSPENSION 3C-9 C ertain precautions should be observed when in­ specting shocks for leaks: • shocks m ay have glossy paint on them . Do not confuse this paint with a leak condition. • a slight trace of shock fluid around the seal cover area is not cause for replacem ent. The shock seal is engineered to perm it a slight seepage to lubricate the rod. The shock absorber has reserve fluid to com pen­ sate for the slight seepage. • shocks are som etim es in co rrectly diagnosed as leakers due to oil spray originating from some other source. If in doubt, wipe the wet area from and m anually operate shock as described in Step (2). Fluid will reappear if shock is leaking. 2. M anually O perating Shocks. It m ay be necessary w ith ce rta in types of shock m ountings to fabricate a bracket th a t can be installed on a shock to enable a technician to securely grip the shock when m anually operating the shock. See Figure 3C-9 for suggested m ethods of providing tem porary grip. T his te st should help th e m echanic to isolate the following shock defects: • binding condition internally • verify leaking shock • im proper or defective valving (a) If suspected problem is in front shocks, disconnect both front shock lower m ountings and stroke each shock as follows: G rip the lower end of the shock securely and pull down (rebound stroke) then push up (compression stroke). The control arm s will limit the m ovement of the front shocks during the com­ pression stroke. C o m p are th e rebound resistance between both front shocks, then com pare the com­ pression resistance. If a noticeable difference can be felt during either stroke, usually the shock having the least resistance is at fault. (b) If shock has an internal noise condition, extend shock fully, then exert an extra pull. If noisy, shock should be replaced. O ther noise conditions th at require shock replace-^ ment are: • a grunt or squeal after one full stroke in both directions • a clicking noise on fast reverse • a skip or lag at reversal near m id-stroke W hen air adjustable shocks are being m anually oper­ ated , the air line m ust be disconnected at the shock absorber. BENCH CHECKS The bench checks are recommended if the proper type hoist is not available to perform the "on vehicle" tests, or if th ere is still some doubt as to w hether the shocks are defective. In addition, the bench test allows a more thorough visual inspection. Bench check procedures are discussed for three general types of shocks. SPIRAL GROOVE RESERVOIR If this type of shock has been stored or allowed to lay in a horizontal position for any length of time, an air void will develop in the pressure cham ber of the shock absorber. This air void if not purged, can cause a technician to diagnose the shock as defective. To purge the air from the pressure cham ber, proceed as follows: (R efer to Figure 3 C -10) (a) Holding the shock in its normal vertical position (top end up), fully extend shock. (b) Hold the top end of the shock down and fully collapse the shock. (c) Repeat Steps (a) and (b) at least five (5) times to assure air is purged. Bench Test Procedure 1. This is a comparison type test. If possible, obtain a new or known good shock with same part num ber as shock under test. LIGHT TRUCK SERVICE MANUAL 3C-10 FRONT SUSPENSION AIR ADJUSTABLE SHOCKS TYPICAL FRONT SH O C K TYPICAL REAR SH O C K BOTTOM' MOUNT ROD EXTENDED (REBOU ND)x r\ SHOCKS COLLAPSED ROD EXTENOED (REBOUND) ' TOP END DOWN INVERT. THEN COLLAPSE SHOCK COLLAPSED X BOTTOM MOUNT fi T~m n TOP END DOWN INVERT, THEN COLLAPSE POSITION FOR PURG ING AIR FROM SH O C K A BSO RBER Fig. 3C-10--Position for Pu rging A ir From Shocks 2. W ith shocks in vertical position (top end up), clamp bottom mounts in vise. Do not clam p on reservoir tube or m ounting threads. 3. M anually pum p each shock by hand at various rates of speed and com pare resistance of suspected shock with the new one. Rebound resistance (extending the shock) is normally stro n g er th an the com pression resistance (a p p ro x ­ im ately 2:1). However, resistance should be smooth and constant for each stroking rate. 4. Observe or listen for the following conditions th at will indicate a defective shock: • a skip or lag when reversing stroke at mid travel. • seizing or binding condition except at extrem e end of either stroke. • a noise, such as a g ru n t or squeal, after completing one full stroke in both directions. • a clicking type noise at fast reversal. • fluid leakage. 5. To check for a loose piston, com pletely extend shock to full rebound; then exert an extra hard pull. If a give is felt, a loose piston is indicated and shock should be replaced. PLIACELL OR GENETRON Pliacell and G enetron are some of the trade nam es used to indicate a gas-filled cell in the shock reservoir. The reservoirs of Pliacell and G en etro n shocks are sm ooth, com pared to the spiral groove type. The cell takes the place of air in the reservoir. Thus, aeration or foaming of the fluid is elim inated, as air and fluid cannot mix. Due to this featu re, these shocks should be bench checked in an inverted position (top end down). If, when stroked, a lag is noticed, it m eans the gas-filled cell has been ruptured, and the shock should be replaced. If no lag is noticed, the rem ainder of the bench check is the same as given in the Spiral Groove Reservoir, Section 1, Bench Check Procedure. LIGHT TRUCK SERVICE MANUAL This type of shock contains an air cham ber like the spiral groove reservoir type, and must have the air purged from the working cham ber. See Section 1, Spiral Groove Reservoir. A fter air has been purged from shock, proceed as follows: (a) Clam p lower shock mounting ring in vise in vertical position with larger diam eter tube at the top. (b) Pump unit by hand at different rates of speed. Smooth resistance should be felt through the length of the stroke. Since the units are norm ally pressurized, the sound of air bubbles or a gurgling noise is normal. (c) The rem ainder of the bench check is the same as given in the Spiral Groove Reservoir, Section 1, Bench Check Procedure. BEARINGS AND RACES BENCH DIAGNOSTIC PROCEDURE This section describes common types of bearing distress and their causes. Illustrations are included to help diagnose the cause of distress and comments are provided to help make effective repairs. Consider The Following Factors When Diagnosing Bearing Distress: 1. N ote G eneral Condition of all parts during teardown and exam inations. 2. Classify the failure with the aid of these illustrations where possible. 3. D eterm ine the cause. R ecognizing the cause will perm it correction of the problem and prevent a repeat failure of the same type. 4. M ake all repairs following recom m ended procedures. Common Causes For Bearing Distress Include The Following: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. Improper adjustm ent or preloading. M ounting or teardown abuse. Im proper m ounting methods. Inadequate or wrong lubricants. Entrance of dirt or water. W ear from dirt or metal chips. Corrosion or rusting. Overload. Overheating causing tem pering. Frettage of bearing seats. Brinelling from im pact loads and shipping. M anufacturing defects. FRONT SUSPENSION 3C-11 BEARINGS AND RACES FRONT WHEEL, PIN IO N , DIFFERENTIAL SIDE A N D REAR WHEEL ROLLER BEARINGS DIAGNOSIS EXCESS NO ISE C O M P L A IN T D IA G N O S T IC PRO CEDURE Road Test 1. 2. 3. 4. 5. 5. Change tire pressure to minimize noises Drive over different road surfaces S m oo th black-top minimizes tire noise Cross switch tires, if necessary Snow tire treads and studs caused added noises Engine or Exhaust Noises 1. 2. 3. 4. Drive slightly above speed where noise occurs, place transmission in neutral Let engine speed drop to idle Stop car Run engine at various speeds Test for Wheel Bearing Noise 1. 2. 3. 4. Drive car at low speed on a sm o o th road Turn car to develop left and right m otions, traffic permitting Noise should change due to cornering loads Jack-up wheels to verify roughness at wheels Test for Differential Bearing Noise 1. 2. 3. 4. Drive car at low speed on a sm ooth road Constant low pitch bearing noise may be heard Noise should not change in reversing turns Noise pattern should vary with wheel speed 1. 2. 3. 4. Roughness or whine noise should increase with speed Noise pitch should be higher than differentials Test on sm o o th road to minimize tire noises Test at various speeds in drive, float, and coast Rear pinion bearing noise m ay be louder on acceleration Fro nt pinion bearing noise m ay be louder on deceleration Gear noises tend to peak in a narrow speed range Tire Noises Test for Pinion Bearing Noise 1. 2. 3. 4. Check tires for irregular wear Check tire pressure Check lubricant level Drive to warm -up rear axle Test at various speeds in drive, float, coast and cornering 5. 6. 7. Fig. 3C-11--Bearing Diagnosis Chart LIGHT TRUCK SERVICE MANUAL 3C-12 FRONT SUSPENSION FRONT WHEEL BEARING DIAGNOSIS CONSIDER THE FOLLOWING FAC T O R SW H E N DIAGNO SING BE AR ING CO NDIT ION: 1. G E N E R A L CONDITION OF A L L PARTS DURING DISASSEMBLY AN D INSPECTION. 2. CL ASSIF Y THE F A IL U R E WITH THE A I D OF THE ILLUST RAT IO N S. 3. D E T ERM INE THE CAUSE. 4. M AKE A L L REPAIRS FOLLO WING RECOMMENDE D PROCEDURES. GOOD BEARING BENT CAGE CAGE D AM AG E DUE TO H A N D L IN G OR TOOL USAGE. BENT CAGE IMPROPER REPLACE BEARING. G A LLIN G M E T A L SMEARS ON R O L L E R ENDS DUE TO O V E R H E A T , L U B R IC A N T F A IL U R E OR OVERLOAD. REPLACE BE ARING - CHECK SEALS A N D CHECK FOR PROPER L U B R IC A T IO N . M IS A L IG N M E N T OUTER RAC E M IS A L IG N M E N T DUE TO FOREIGN OBJECT. CLEA N R E L A T E D PARTS A N D REPLACE BE ARING. M A K E SURE RACES ARE PROPERLY SEATED. ABRASIVE STEP WEAR IMPROPER REPLACE BEARIN G. ETCHING BEARING SURFACES APPEAR G R A Y OR G R A Y IS H BL A C K IN COLOR WITH R EL A TE D ETCHING A W A Y OF M A T E R I A L CLEA N A L L PARTS A N D HOUSINGS, U S U A L L Y A T R O L L E R SPACING. CHECK SEALS A N D BE ARINGS AN D R EP L AC E IF L E A K IN G , ROUGH OR REPLACE BEARINGS CHECK SEALS NOISY. A N D CHECK FOR PROPER L U BR IC A TIO N . PATTERN ON RO L L ER ENDS CAUSED BY FINE AB RASIVES. IN D EN TA TIO N S FA TIG U E SPALLING METAL OF SURFACE SURFACE DEPRESSIONS ON RACE AND F L A K I N G RO LLERS CAUSED BY H AR D PA RTICLES RESUL TING FROM F ATIG U E . OF FOREIGN M A T E R I A L . CLEA N A L L REPLACE BE ARING CLEAN A L L PARTS A N D HOUSINGS, R E L A TE D PARTS. CHECK SEALS A N D REPLACE BE ARINGS IF ROUGH OR NOISY. Fig. 3C-12--Bearing Diagnosis Illustration A LIGHT TRUCK SERVICE MANUAL CAGE DAM AG E DUE TO H A N D L IN G OR TOO L USAGE. FRONT SUSPENSION 3C-13 FRONT WHEEL BEARING DIAGNOSIS (CONT’D) B R IN ELLING CAGE WEAR SURFACE IN DEN TAT IO NS IN RACEWAY CAUSED BY RO LLERS EITHER U NDE R IMPACT L O A D IN G OR V I B R A T IO N W HIL E THE BEARING IS NOT R O T A TIN G . WEAR A R O U N D OUTSIDE DIAM ETER OF CAGE AND ROLLER POCKETS CAUSED BY A B R A S IV E M A T E R IA L AND IN E F F IC IE N T L U B R IC A TIO N . CHECK SEALS A ND REPLACE BEARINGS. REPLACE BEARING IF ROUGH OR NOISY. CRACKED INNER RACE RACE CRACKED DUE TO IMPROPER FIT, COCKING, OR POOR BEARING SEATS. SMEARS SMEARING OF M E T A L DUE TO SLIPPAGE, SLIPPAGE CAN BE CAUSED BY POOR F IT S , L U B R IC A T IO N , O V E R H E A T IN G , O VE RLO ADS OR H A N D L IN G DA MAGE. REPLACE BEARINGS, CLEA N R EL A TE D PARTS AND CHECK FOR PROPER FIT AND LUBRICA TIO N. REPLACE SHAFT IF ABRASIVE ROLLER WEAR PATTERN ON RACES AND CAUSED BY FINE AB RASIVES. RO LLERS CLEAN A L L PARTS A N D HOUSINGS CHECK SEALS A N D BEARINGS AND REPLACE IF L E A K IN G , ROUGH OR NOISY. FRETTAGE CORROSION SET UP BY SMALL R E L A T IV E M O VEM ENT OF PARTS WITH NO L U BR IC A TIO N . REPLACE BE ARIN G. CLEAN R E L A TE D PARTS. CHECK SEALS A N D CHECK FOR PROPER L U BR IC A TIO N . DAM AG E D. HEAT DISCO LORATION H E A T DISCOLORATIO N CAN RANGE FROM F A I N T YE LLO W TO D A R K BLUE R E S U L T IN G FROM O V E R L O A D OR INCORRECT L U BRICA NT. EXCESSIVE HEAT CAN CAUSE SOFTENING OF RACES OR RO LLERS. TO CHECK FOR LOSS OF TEMPER ON RACES OR ROLLERS A SIMPLE FILE TEST MAY BE M ADE. A FILE DRAWN OVER A TEMPERED PART W I L L GRAB A N D CUT META, WHEREAS, A FILE DRAWN OVER A H AR D PART W I L L G LIDE R E A D I L Y WITH NO M E T A L CUTTING. REPLACE BE ARINGS IF OVER HEA TING DA MAGE IS IN DICAT ED. CHECK SEALS AN D OTHER PARTS. STAIN DISCOLO RATIO N DISCOLORATIO N CAN RANGE FROM LIG H T BROWN TO BLACK CAUSED BY INCORRECT L U B R IC A N T OR MOISTURE. RE-USE BEARINGS IF STAINS CAN BE REMOVE D BY LIG HT POLISHING OR IF NO EVIDENCE OF O V E R H E A T IN G IS OBSERVED. CHECK SEALS A N D R E L A T E D PARTS FOR DAMAGE. Fig. 3C-13--Bearing Diagnosis, Illustration B i iruT tp! \ r v Q T D \ • •«•" IA| 3C-14 FRONT SUSPENSION COMPONENT PARTS REPLACEMENT WHEEL HUBS, BEARINGS (Fig. 3C-14) Rem oval C, G an d P Series 1. R aise vehicle on hoist and rem ove wheel and tire assem bly. Remove d u st cap from end of hub and w ithdraw cotter pin. 2. Remove the brake caliper and hang by wire to the suspension. Do not allow the caliper assembly to hang by the brake flex line. 3. Remove hub and disc assembly. 4. Remove outer bearing from hub. The inner bearing will rem ain in the hub and may be removed by prying out the inner grease seal. 5. W ash all parts in cleaning solvent. 2. 3. 4. Inspection 1. Check all bearings for cracked bearing cages, worn or pitted rollers. 2. Check bearing races for cracks or scoring, check brake discs for out-of-round or scored conditions and check bearing outer races for looseness in hubs. 5. Repairs Replacement of Bearing Cups If necessary to replace an outer race, drive out old race from the hub with a brass drift inserted behind race in notches in hub. Install new race by driving it into hub with the proper race installer J-8457, J-8458, J-8849 or J-92762. Remove an,d install the inner race in the same manner. NOTICE: Use care when installing new race to start it squarely into hub, to avoid distortion and possible cracking. Wheel Stud Replacement (Fig. 3C-14) Use a piece of w ater pipe or other sim ilar tool to support the hub while pressing a wheel stud either in or out. Installation See N O T IC E on page regarding the fasteners referred to in 1. C lean off any grease in th e hub thoroughly clean out any grease in NO TICE: 1 of this section steps 8 and 9. and spindle and the bearings. Use Fig. 3C-14--Pressing Hub Bolt i jo ht T r y o k m an u a } 6. cleaning solvent. Use a sm all brush w ith no loose bristles to clean out all old grease. Do not spin the bearing with compressed air while drying it or the bearing may be dam aged. Use a G M approved high tem perature front wheel bearing grease or equivalent. Do not mix greases as mixing may change the grease properties and result in poor perform ance. Apply a thin film of grease to the spindle at the outer bearing seat and at the inner bearing seat, shoulder, and seal seat. Put a small quantity of grease inboard of each bearing cup in the hub. This can be applied with your finger forming a dam to provide extra grease availability to the bearing and to keep thinned grease from flowing out of the bearing. Fill the bearing cone and roller assemblies 100% fill of grease. A method for doing this is with a cone type grease machine th at forces grease into the bearing. If a cone g reaser is not available, the bearings can be packed by hand. If hand packing is used, it is extrem ely im p o rtan t to work the grease thoroughly into the bearings betw een the rollers, cone, and th e cage. Failure to do this could result in prem ature bearing failure. Place the inner bearing cone and roller assembly in the hub. Then using your finger, put an additional quantity of grease outboard of the bearing. 7. Install a new grease seal using a flat plate until the seal is flush with the hub. L ubricate the seal lip with a thin layer of grease. 8. Carefully install the hub and rotor assembly. Place the outer bearing cone and roller assembly in the outer bearing cup. Install the washer and nut and initially tighten the nut to 12 ft. lbs. while turning the wheel assembly forward by hand. Put an additional quantity of grease outboard the bearing. This provides extra grease availability to the bearing. 9. Final wheel bearing adjustm ent should be perform ed as previously outlined. Fig. 3C-15--Shock Absorber Attachments FRONT SUSPENSION SHOCK ABSORBER COIL SPRING Removal (Fig. 3C-15) Removal (Fig. 3C-17) 1. Raise vehicle on hoist. 2. Remove nuts and eye bolts securing upper and lower shock absorber eyes. 3. W ith d ra w shock absorber and inspect rubber eye bushings. If defective, replace shock absorber assembly. Installation Place shock absorber into position over mounting bolts or into mounting brackets. Install eye bolts and nuts and torque as shown in Specifications Section. Lower vehicle to floor. STABILIZER BAR Removal (Fig. 3C-16) 1. Raise vehicle on hoist and remove nuts and bolts attaching stabilizer brackets and bushings at frame location. 2. Remove brackets and bushings at lower control arms and remove stabilizer from vehicle. 1. Place vehicle on hoist and place jack stands under frame, allowing control arms to hang free. 2. Disconnect shock absorber at lower end and move aside. Disconnect the stabilizer bar attachments to the lower control arm. 3. Bolt Tool J-23028 to a suitable jack. 4. Place tool under cross-shaft so that the cross-shaft seats in the grooves of the tool. As a safety precaution install and secure a chain through the spring and lower control arm. 5. Raise the jack to remove tension on the lower control arm cross-shaft and remove the two " U " bolts securing the cross-shaft to crossmember. The crosshaft and lower control arm keeps the coil spring compressed. Use care when lowering. 6. Lower control arm by slowly releasing the jack until spring can be removed. Be sure all compression is relieved from spring. 7. Remove spring. Installation Inspection Inspect rubber bushings for excessive wear or agingreplace where necessary. Use rubber lubricant when install­ ing bushings over stabilizer bar. 1. Installation NOTICE: See N O T I C E on page 1 of this section 3C-15 2. regarding the fasteners referred to in step 2. Slit in bar to frame bushings should be facing forward. 1. Place stabilizer in position on frame and install frame brackets over bushings. Install nuts and bolts loosely. 3. 4. 2. Install brackets over bushings at lower control arm location. Be sure brackets are positioned properly over bushings. Torque all nuts and bolts to specifications. 3. Lower vehicle to floor. 5. 6. NOTICE: See N O T I C E on page 1 of this section regarding the fasteners referred to steps 3 and 4. Properly position spring on the control arm, and lift control arm using jack and tool J-23028. Some models are equipped with air cylinders in the coil springs. These cylinders should be checked for leaks and damage at this time. Air pressure in these cylinders should be 40 PSI ± 1 0 . Position control arm cross-shaft to crossmember and install " U " bolts and attaching nuts. Make certain front indexing hole in cross-shaft is lined up with crossmember attaching saddle stud. Torque nut to specifications. Install shock absorber to lower control arm and install stabilizer bar. Remove tool J-23028 and safety chain. Lower vehicle to floor. Fig. 3C-17--Removing Coil Spring with Tool J-23028 L IG H T T R U C K SERVICE M AN U AL 3C-16 FRONT SUSPENSION UPPER CONTROL ARM INNER PIVOT SHAFT AND/OR BUSHING REPLACEMENT C20-30, G30 and P20-30 (Steel Bushings) Pivot Shaft Removal 1. Raise vehicle and remove tire and wheel assembly. 2. Support the lower control arm with a floor jack. Position jack under the ball joint assembly or as near as possible and still have good support. 3. Loosen the upper control arm shaft end nuts before loosening the shaft to frame attaching nuts. 4. Loosen the shaft to frame nuts and remove the caster and camber shims. Tape the shims together as they are removed and mark for position. 5. Remove the pivot shaft to frame nuts but do not allow the arm to swing too far away from the frame. Use a safety chain to retain the arm in a close relationship to the frame. See Fig. 3 C -18. 6. Remove the shaft end nuts and remove shaft from arm. Bushing Replacement (Steel Bushings) 1. Remove grease fittings from bushing outer ends and unscrew bushings from control arm and shaft. 2. Slide new seal on each end of shaft and insert shaft into control arm. 3. Start new bushings on shaft and into control arm. Adjust shaft until it is centered in control arm, then turn bushings in and torque to specifications. Figure 3C-19 shows correct final positioning of shaft. Check shaft for free rotation and install grease fittings. Installation NOTICE: See N O T I C E on page 1 of this section regarding the fasteners referred to in steps 3, 5 and 6. W hen installing the upper control arm be sure to properly position the special aligning washers to the pivot shaft with convex and concave sides together. 1. Install the shaft to the control arm and install end nuts. Do not torque nuts at this time. 2. Position cross shaft to frame bolts and start cross shaft nuts. 3. Torque the shaft end nuts. See Fig. 3C-19 for proper spacing. The shaft should rotate by hand after the nuts are torqued. 4. Install caster and camber shim in their appropriate places. 5. Torque the cross-shaft to frame nuts. 6. Remove the safety chain and install the tire. 7. Lower vehicle to the floor. LOWER CONTROL ARM INNER PIVOT SHAFT AND/OR BUSHING REPLACEMENT C20-30, G30, P20-30 (Steel Bushings) Lower-Removal (Fig. 3C-18) 1. Raise vehicle and support the frame so that control arms hang free. 2. Position an adjustable floor jack under the control arm inboard of spring and into depression in lower arm. 3. Install a chain over upper arm (Fig. 3C-18). Inboard of stabilizer and outboard of shock absorber as a safety measure. 4. Disconnect shock absorber at lower control arm. 5. Loosen shaft end nuts. 6. Remove " U " bolts. 7. Lower jack just enough to get at shaft. 8. Remove shaft end nuts and remove shaft. Bushing Replacement (Steel Bushings) 1. Remove grease fittings from ends of bushings and unscrew bushings from shaft and control arm. Remove shaft and seals. Fig. 3C-18--Removing Inner Pivot Shaft LIG H T T R U C K SE RV IC E M AN U AL Fig. 3C-19--Positioning U.C.A. Shaft (Steel Bushings) FRONT SUSPENSION 3C-17 J—2 4 4 35 -7 J—24435-1 Fig. 3 C -2 2 -U .C .A . Rubber Bushing Rem oval 3. Install " U " bolts. Do not torque nuts at this time. 4. Torque cross-shaft end nuts. The shaft should roate by hand after the nuts are torqued. Fig. 3C-20--Positioning L.C.A. Sh aft (Steel Bushings) 5. Torque " U " bolt nuts. 6. Remove safety chain. 2. Slide new seal on each end of shaft and insert shaft into control arm. 3. Start new bushings on shaft and into control arm. Adjust shaft until it is centered in control arm, then turn bushings in and torque to specifications. Check shaft for free rotation. Figure 3C-20 shows correct final positioning of shaft. Installation NOTICE: See N O T I C E on page 1 of this section regarding the fasteners referred to in steps 4 and 5. 1. Install shaft to control arm and install end nuts. Do not torque nuts at this time. 2. Raise jack and position shaft into crossmember saddle. Be sure to index hole in shaft to mate with bolt head in saddle. 7. Lower vehicle to floor. UPPER CONTROL ARM ASSEMBLY All Removal 1. Raise vehicle on hoist, remove wheel and tire assembly and support lower control arm assembly with adjusta­ ble jackstand. 2. It is necessary to remove the brake caliper assembly and wire it to the frame to gain clearance for tool J-23742. See section 5 for proper procedure. 3. Remove cotter pin from upper control arm ball stud and loosen stud nut one turn. 4. Loosen upper control arm ball stud in steering knuckle, using Tool J-23742 position as shown in Figure 3C-21. Remove the nut from the ball stud and raise upper arm to clear steering knuckle. J —2 4 4 3 5 -7 J—2 4 4 3 5 -4 J— 2 4 4 3 5 -5 (HIDDEN) Fig. 3C-21--Disconnecting Ball Joints from Knuckle Fig. 3C-23--U.C.A. Rubber Bushing Installation L IG H T T R U C K SERVICE M AN U AL 3C-18 FRONT SUSPENSION 5. Remove nuts securing control arm shaft to frame. W ithdraw control arm assembly. Tape shims together and tag for proper relocation when control arm is reinstalled. Upper Control Arm Inner Pivot Shaft and/or Bushing Replacement CIO, G10-20, P10 (Rubber Bushings) Removal (Fig. 3C-22) 1. Remove the upper control arm using the preceding procedure and mount the control arm in a vise. 2. Install remover J-24435-1, receiver J-24435-3 and " C " clamps J-24435-7 as shown in Figure 3C-22. 3. Tighten the clamp to draw out the old bushing. Discard old bushing. 4. The pivot shaft may now be removed from the control arm assembly. 5. Reposition the control arm in the vise and repeat the removal procedure on the remaining bushing. Bushing Installation 1. Again using " C " clam p J-24435-7 and installers J-24435-4 (outer) and J-24435-5 (inner) tighten clamp to install bushing onto control arm. 2. Install pivot shaft into inside diameter of first installed bushing. 3. Install remaining bushing as shown in Figure 3C-23 and described in step 1. 4. Remove tools and install control arm on vehicle following procedure described below. Torque all fasten­ ers to proper specifications. Upper Control Arm Installation NOTICE: See N O T I C E on page 1 of this section regarding the fasteners referred to in steps 1, 2 and 3. W hen installing the upper control arm be sure to position the special aligning washers to the pivot shaft with concave and convex sides together. Fig. 3C-24--Lowering Control Arm for Bushing Replacement L IG H T T R U C K SE RV IC E M AN U AL 1. Place control arm in position on bracket and install nuts. Before tightening nuts, insert caster and camber shims in the same order as when removed. Torque the nuts to specifications. A normal shim pack will leave at least two (2) threads of the bolt exposed beyond the nut. If two (2) threads cannot be obtained: Check for damaged control arms and related parts. Difference between front and rear shim packs must not exceed 7.62 mm (.30 inches). Front shim pack must be at least 6.09 mm (.24 inches). Always tighten the thinner shim packs’ nut first for improved shaft to frame clamping force and torque retention. 2. Insert ball joint stud into steering knuckle and install nut. Torque stud nut to specifications and install cotter pin. 3. Install brake caliper assembly if removed (see section 5). 4. Remove adjustable support from under lower control arm. Install wheel and tire assembly. 5. Lower the vehicle to the floor. LOWER CONTROL ARM ASSEMBLY Removal 1. Raise vehicle on hoist and remove spring as outlined under spring removal. Support the inboard end of the control arm after spring removal. 2. Remove cotter pin from lower ball stud and loosen stud nut one turn. 3. Install Ball Stud Remover J-23742, position large cup end of the tool over the upper ball stud nut and piloting the threaded end of tool on end of the lower ball stud. Extend bolt from Tool J-23742 to loosen lower ball stud in steering knuckle. When stud is loosened, remove tool and nut from lower stud. It is necessary to remove the brake caliper assembly and wire it to the frame to gain clearance for tool J-23742. See section 5 for proper procedure. 4. Remove the lower control arm. Fig. 3C-25--L.C.A. Rubber Bushing Removal FRONT SUSPENSION Lower Control Arm Inner Pivot Shaft and/or Bushing Replacement-On Vehicle CIO (Rubber Bushings) Removal (Figs. 3C-24, 3C-25) If just bushings or pivot shaft are to be replaced the lower control arm does not have to be removed from the vehicle. 1. Raise vehicle on hoist and support the frame so that the control arms hang free. 2. Position an adjustable floor jack under the lower control arm inboard of spring and into depression of control arm. 3. Install a chain over the upper arm inboard of the stabilizer and outboard of shock absorber as a safety measure. 4. Disconnect shock and stabilizer bar attachments at lower control arm. 5. Loosen shaft end nuts. 6. Remove " U " bolts that retain the inboard end of the lower control arm. 7. Lower jack S L O W L Y to release spring compression (Fig. 3C-24) and gain clearance to remove bushings. Be sure all compression is released from coil springs. 8. Remove the stakes on the front bushing using tool J-2 2 7 17 or equivalent tool. 9. Bushings may now be replaced. Install " C " clamps J-24435-7 and receiver J-24435-3 with remover J-24435-2 and spacer J-24435-6 as shown in Figure 3C-25. 10. Tighten the " C " clamp to remove the bushing. 11. Remove tools and discard old bushing. 12. Pivot shaft may now be removed if necessary. 13. Remove second bushing (leave pivot shaft in to pilot tool) by the same method as in steps 8-12. Bushing Installation (Fig. 3C-26) NOTICE: See N O T I C E on page 1 of this section regarding the fasteners referred to in step 5. 1. Install new bushings as shown in Figure 3C-26 using spacer J-24435-6, installer J-24435-4 and " C " clamp J-24435-7. 2. Turn clamp in until bushing seats firmly. 3C-19 2. Remove pivot shaft nuts. 3. Place control arm in an arbor press, press front end of pivot shaft to remove rear bushing, and pivot shaft assembly. 4. Remove the stakes on the front bushing using Tool J-2 2 7 17 or equivalent tool. 5. Install " C " clamp J-24435-7 and receiver J-24435-3 with remover J-24435-2 and spacer J-24435-6 as shown in Figure 3C-25. 6. Tighten " C " clamp to remove the bushing. Installation NOTICE: See N O T I C E on page 1 of this section regarding the fasteners referred to in step 5. 1. Install new bushings as shown in Figure 3C-26 using spacer J-24435-6, installer J-24435-4 and " C " clamp J-24435-7. 2. Turn clamp in until bushing seats firmly. Be sure outer tube hole is to the front or forwards to the staked bushing. NOTICE: Be sure spacer J-24435-6 is in position as shown in Figure 3C-26 to avoid collapsing control arm during assembly. 3. Stake front bushing at least in two places when installed. 4. Insert the pivot shaft and install second bushing. 5. Install the lower control arm to the vehicle as described under "Lower Control Arm - Installation", being sure to torque all fasteners to the proper specification. Lower Control Arm Installation NOTICE: See N O T I C E on page 1 of this section regarding the fasteners referred to in steps 2 and 3. 1. Install lower ball stud through steering knuckle and tighten nut. 2. Install spring and control arm as outlined under spring installation. 3. Torque lower control arm ball stud to specifications and install cotter pin. 4. Install brake caliper assembly if removed (see section 5). 5. Lower the vehicle to the floor. NOTICE: Be sure spacer J-24435-6 is in position as shown in Figure 3C-26 to avoid collapsing control arm during assembly. 3. Install one bushing then insert the pivot shaft and install second bushing. 4. Stake front bushing at least in two places when installed. 5. Install the lower control arm to the vehicle as described under "Lower Control Arm - Installation", being sure to torque all fasteners to the proper specification. Lower Control Arm Inner Pivot Shaft And Bushing Replacement-G10-G20 Models Removal 1. Remove lower control arm as previously outlined. Fig. 3C-26--L.C.A. Rubber Bushing Installation L IG H T T R U C K SE RV IC E M AN U AL 3C-20 FRONT SUSPENSION R E M O VE UPPER R EM O VE LO W ER HE A V Y FLAT W ASHER I J— 2 3 7 4 2 , J— 2 3 7 4 2 Fig. 3C-27--Disconnecting Ball Joints-Typical 1. Install new service ball joint, using bolts and nuts supplied with joint, to upper arm. Torque nuts to 60 N-m (45 ft. lbs.). 2. M ate ball stud to steering knuckle and install stud nut. 3. Torque the ball stud nut as follows: A .10 Series 54-80 N-m (40-60 ft. lbs.) plus additional torque to align cotter pin not to exceed 120 N-m (90 ft. lbs.). Never back off to align cotter pin. B.20-30 Series 110-140 N-m (80-100 ft. lbs.) plus additional torque to align cotter pin not to exceed 175 N-m (130 ft. lbs.) Never back off to align cotter pin. 4. Install new cotter pin as shown in Figure 3C-28. 5. Install lube fitting and lube new joint. 6. Install brake caliper assembly if removed (see section 5). 7. Install tire and wheel assembly. 8. Lower the vehicle to the floor. BALL JOINT SERVICE-ON VEHICLE Ball Joint-lnspection Ball Joint-lnspection The upper ball stud is spring loaded in its socket. This minimizes looseness at this point and compensates for normal wear, if the upper stud has any perceptible lateral shake, or if it can be twisted in its socket with the fingers, the upper ball joint should be replaced. Upper-Removal 1. Raise vehicle on hoist. If a frame hoist is used, it will be necessary to support the lower control arm with a floor jack. 2. Remove cotter pin from upper ball stud and loosen stud nut (two turns) but do not remove nut. 3. Install J-23742 between the ball studs as shown in Figure 3C-27. It is necessary to remove the brake caliper assembly and wire it to the frame to gain clearance for tool J-23742. See section 5 for the proper procedure. 4. Be sure lower control arm is supported as pointed out in step 1. Extend bolt from Tool J-23742 to loosen ball stud in steering knuckle. When stud is loose, remove tool and stud nut. 5. Center punch rivet heads and drill out rivets. 6. Remove the ball joint assembly. Lower Lower ball joints are a loose fit when not connected to the steering knuckle. W ear may be checked without disas­ sembling the ball stud, as follows: 1. Support weight of control arms at wheel hub and drum. 2. Accurately measure distance between tip of ball stud and tip of grease fitting below ball joint. 3. Move support to control arm to allow wheel hub and drum to hang free. Measure distance as in Step 2. If the difference in measurements exceeds 2.38 mm (.094" (3 /3 2 " ) for all models, ball joint is worn and should be replaced (Fig. 3C-29). Lower-Removal 1. Raise vehicle on a hoist. If a frame hoist is used it will be necessary to support the lower control arm with a floor stand. 2. Remove the tire and wheel assembly. 3. Remove the lower stud cotter pin and loosen (two turns) but do not remove the stud nut. Installation NOTICE: See N O T I C E on page 1 of this section regarding the fasteners referred to in steps 1, 3 and 6. Fig. 3C-29--Checking Lower Ball Joint LIG H T T R U C K SE RV IC E M A N U A L FRONT SUSPENSION 4. Install J-23742 between the ball studs as shown in Figure 3C-27. It may be necessary to remove the brake caliper assembly and wire it to the frame to gain clearance for tool J-23742. See section 5 for proper procedure. 5. Be sure lower control arm is supported as pointed out in Step 1. Extend bolt from Tool J-23742 to loosen ball stud in steering knuckle. When stud is loosened, remove tool and ball stud nut. 6. Pull the brake disc and knuckle assembly up off the ball stud and support the upper arm with a block of wood so that assembly is out of working area. NOTICE: Do not put stress on the brake line flex hose or damage to the brake line may result. 7. Install Tools J - 9 5 19-10 and J-9519-2 and J-9519-29 as shown in Fig. 3C-30. 8. Turn hex head screw until ball joint is free of control arm. 9. Remove tools and the ball joint. Installation (Fig. 3C-31) NOTICE: See N O T I C E on page 1 of this section regarding the fasteners referred to in steps 4, 5 and 7. 1. S tart the new ball joint into the control arm and install J - 9 5 19-10 and J-9 5 19-16 as shown. Position bleed vent in rubber boot facing inward. 2. Turn hex head screw until ball joint is seated in control arm. 3. Lower the upper arm and mate the steering knuckle to the lower ball stud. 4. Install brake caliper assembly if removed (see Section 5). 5. Install ball stud nut and torque as follows. All Series, 110 - 140 N-m (80-100 ft. lbs.) plus additional torque to align cotter pin hole not to exceed 175 N-m (130 ft. lbs.) maximum. Never back off to align cotter pin. 6. Install a lube fitting and lube the joint. 7. Install tire and wheel assembly and lower vehicle to floor. 3C-21 STEERING KNUCKLE It is recommended that vehicle be raised and supported as on a twin-post hoist so that the front coil spring remains compressed, yet the wheel and steering knuckle assembly remain accessible. If a frame hoist is used, support lower control arm with an adjustable jackstand to safely retain spring in its curb height position. Removal 1. Raise vehicle on hoist and support lower control arm as noted above. 2. Remove wheel and tire assembly. 3. Remove caliper as outlined under "Front Wheel Hub Removal". 4. Remove disc splash shield bolts securing the shield to the steering knuckle. Remove Shield. 5. Refer to Section 3B-Steering for service removal operations. 6. Remove upper and lower ball stud cotter pins and loosen ball stud nuts. Free steering knuckle from ball studs by installing Special Tool J-23742. Remove ball stud nuts and withdraw steering knuckle. Installation NOTICE: See N O T I C E on page 1 of this section regarding the fasteners referred to in steps 2, 3 ,4 and 5. 1. Place steering knuckle in position and insert upper and lower ball studs into knuckle bosses. Steering knuckle hole, ball stud and nut should be free of dirt and grease before tightening nut. 2. Install ball stud nuts and tighten nut to specifications. (See Specification Section.) If necessary, tighten one more notch to insert cotter pins. Do not loosen nut to insert cotter pin. Refer to Ball Joint text for proper nut installation sequence. 3. Reverse rem aining removal procedure, and tighten splash shield m ounting bolt. Tighten two caliper assembly mounting bolts to 48 N-m (35 ft. lbs.) torque. 4. Adjust wheel bearings as outlined under Front Wheel Bearing Adjustment. 5. Tighten wheel nuts to 100 N-m (75 ft. lbs.). J-9519-2 (HIDDEN) J-9519-29 J -9 5 19-16 J -9 5 19-1 0 J -9 5 19-10 BALL JOINT REMOVAL Fig. 3C-30--Ball Joint Removal BALL JOINT INSTALLATION Fig. 3C-31—Installing Ball Joint LIG H T T R U C K SE RV IC E M AN U AL 3C-22 FRONT SUSPENSION CROSSMEMBER AND SUSPENSION UNIT Com ponent parts of the front suspension may be serviced separately as outlined in the preceding service operations. However, if extensive service is to be performed to crossmember, frame, etc., the unit can be removed and installed as follows: 9. Disconnect fron shock absorbers from lower control arms. 10. Remove brake line clip bolts from front suspension crossmember. On C-Models the clip is located under right hand engine mount support bracket. Removal (Fig. 3C-32) 1. Raise hood and disconnect negative battery cable from battery. 2. Raise vehicle on hoist. 3. Remove front wheels. 4. Disconnect front brake hose clip from each upper control arm. 5. Support front of vehicle with jack stands at frame side rails. Lower front hoist. 6. Clean area adjacent to brake hose fittings. Disconnect front brake hoses from calipers. Discard special wash­ ers (2 each hose). Cover disconnected end of each hose with suitable material. 7. Disconnect tie rod ends from steering knuckles. Dis­ card cotter pins. Refer to Section 3B. 8. If equipped, disconnect front stabilizer from lower control arms. G-MODEL Fig. 3C-32--Suspension Unit to Frame LIG H T T R U C K SE RV IC E M A N U A L 11. 12. 13. 14. 15. 16. NOTICE: Failure to disconnect these clips from the front suspension unit will result in severe damage to the brake line when unit is lowered from vehicle. Remove engine mount support bracket to front suspen­ sion crossmember bolts. Remove crossmember to lower frame rail bolts. Raise hoist to support front suspension unit. Support engine. Engine must be supported adequately before front suspension unit is lowered from vehicle. Remove upper control arm bracket to frame side rail bolts. Suspension unit is now disconnected from vehicle. Lower hoist to lower front suspension unit from vehicle. FRONT SUSPENSION Installation 1. Raise hoist to align new suspension unit with frame rail holes. NOTICE: See N O T I C E , on page 1 of this section regarding fasteners referred to in steps 2-14. 2. Assemble (finger-tight) upper control arm bracket bolts and crossmember bolts to frame rails. 3. Torque upper control arm bracket bolts to frame side rails to 90 N-m (65 ft. lbs.). Control arm bracket bolts must be torqued before crossmember bolts are torqued. Crossmember must be in contact with siderails. 4. Torque crossmember bolts to frame lower rails 100 ft. lbs. Engine support can be removed at this time. 5. Lower hoist. 6. Assemble (finger-tight) engine mount support bracket to front suspension crossmember bolts. 7. Torque engine mount support bracket bolts to 48 N-m (35 ft. lbs.). 3C-23 8. Install brake line clip bolt to front suspension cross­ member. Torque to 17 N-m (150 in. lbs.) (C-models), 12 N-m (100 in. lbs.) (G-models). 9. Connect front shock absorbers to L.C.A.’s. Torque to 80 N-m (60 ft. lbs.) (C-models), 95 N-m (70 ft. lbs.) (G-models). 10. If equipped, connect front stabilizer to L .C .A .’s. Torque to 34 N-m (25 ft. lbs.). 11. Connect tie rod ends to steering knuckles. Refer to Section 3B. 12. Connect front brake hose to caliper, using new special washers. Refer to Section 5. 13. Connect front brake hose clips to upper control arms. T orquenuts to 17 N-m (150in. lbs.). 14. Lubricate upper and lower ball joints. 15. Install front wheels. 16. Bleed brake system. Refer to Section 5 for correct bleeding procedures. 17. Lower vehicle. 18. Connect battery cable. FRONT SUSPENSION, FOUR-WHEEL DRIVE SERIES K IO , K 20, K 30 INDEX General Description......................................................... Maintenance and A djustm ents..................................... Ball Joint A d ju stm e n t................................................ Bearing L u b ricatio n .................................................... Wheel Bearing A djustm ent....................................... Component R eplacem ent............................................... Hubs, Automatic Locking (K10, K 20).................. Hubs, Free-Wheeling ( K 3 0 ) ..................................... 3C -2 3 3 C -2 6 3 C -2 6 3 C -2 6 3 C -2 6 3C -27 3C -27 3C -3 0 S p in d le ........................................................................... Steering Knuckle (K10, K 2 0 ).................................. Steering Knuckle (K 3 0 ) ............................................. Shock A b s o rb e r............................................................ Stabilizer Bar................................................................ Leaf Sp rin g .................................................................... Specifications..................................................................... Special Tools...................................................................... 3 C -3 2 3C -3 3 3 C -3 6 3C -3 8 3C-38 3C-39 3 C -4 0 3C-41 GENERAL DESCRIPTION Front drive axles used on K10, K20, and K30 trucks have several styles of wheel-end construction. Knuckle Attachment At the wheel ends of the axle tubes, two types of steering knuckle attachment are used. Figure 3 C -lK (a) shows the K10 and K20 knuckle attached with ball joints. Figure 3C -lK (b ) shows the king-pin attachment used in K30. The tapered upper king pin fits in a tapered nylon bushing. The lower king pin is part of the bearing cap, and this king pin rides in a tapered roller bearing. Hub Design An automatic locking hub is used on all K10 and K20 models. This system, shown in Figs. 3C -lK (a ) and in 3C3K, automatically engages the hub whenever four-wheel drive is selected. A free-wheeling hub is used on all K30 models. This design is shown in Figs. 3 C -lK (b ) and in 3C-5K. This hub allows the driver to manually engage or disengage the hub from the axle shafts. L IG H T T R U C K SERVICE M AN U AL 3C-24 1. 2. 3. 4. 5. FRONT SUSPENSION R E T A IN IN G S C R E W C O V E R PLATE COVER S E A L I N G R IN G S P R IN G , B E A R IN G RACE 6\ 7 > B E A R IN G A S S E M B L Y 8 ) 9. W I R E R E T A I N I N G R IN G 10. O U T E R C L U T C H H O U S IN G 11. S E A L B R I D G E — R E T A IN E R (N O T SH O W N ) 12. R E T A I N I N G R IN G 13. S P R I N G S U P P O R T W ASHER 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. S P R I N G R E T A IN E R R E T U R N S P R IN G S P R I N G R E T A IN E R CLUTCH G EA R HUB SLEEVE C ’ T Y P E R E T A IN IN G R IN G C O N IC A L S P R IN G CAM FOLLOW ER OUTER CAGE IN N E R C A G E S N A P R IN G BRAKE BAND DRAG SLEEVE AND DETENT 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. SPACER R E T A I N IN G R IN G LO CK NUT R E T A I N IN G W A S H E R A D J U S T IN G N U T O U T E R -W H E E L B E A R IN G IN N E R - W H E E L B E A R IN G S P IN D L E S P IN D L E B E A R IN G SEAL H U B - A N D - D IS C A SSEM BLY O IL S E A L SPACER Fig. 3C-1 K(a)--K10, K20 with Free-Wheeling Hub and Bbll Joints LIG H T TR U C K SE RV IC E M A N U A L 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. D U ST SEAL DEFLECTOR A X LE O U T ER SHAFT KNUCKLE A D J U S T IN G S L E E V E U P P E R B A L L J O IN T YOKE L O W E R B A L L J O IN T R E T A IN IN G R IN G C A L IP E R S U P P O R T BRACKET 50. S P I N D L E R E T A I N I N G NUT 51. S P I N D L E R E T A IN IN G BO LT FRONT SUSPENSION 1. 2. R E T A IN IN G P L A T E " 0 ” R IN G 13. 14. 3. 4. ACTU ATO R KNOB 5. A X L E S H A F T S N A P R IN G 15. 16. 17. 6. 7. A C T U A T IN G C A M B O D Y 18. IN T E R N A L S N A P R IN G 19. 8. O U T E R C L U T C H R E T A I N I N G R IN G 9. AXLE SH AFTSLEEVE AND C L U T C H R IN G I N N E R C L U T C H R IN G S P R IN G LO CK NUT 20. 21. 22. 23. 24. 25. 10. 11. 12. R E T A IN IN G P L A T E B O L T L O C K -A D J . N U T P IN - A D J . N U T A D J U S T IN G N U T O U T E R W H E E L B E A R IN G IN N E R W H E E L B E A R IN G SEAL H U B -A N D - D IS C A S M S P IN D L E S P IN D L E B E A R IN G SEAL DEFLECTOR SPACER L U B E F IT T IN G 26. 27. 28. 29. 30. U P P E R B E A R IN G C A P P R E S S U R E S P R IN G G ASKET B U S H IN G , K IN G - P IN K IN G -P IN 31. YOKE 32. OUTER A XLE SHAFT 33. 34. G R E A S E R E T A IN E R 35. 36. 37. 38. 39. 3C-25 L O W E R B E A R IN G SEAL B E A R IN G C A P L U B E F IT T IN G S P IN D L E A T T A C H IN G N U T S P IN D L E A T T A C H IN G B O L T Fig. 3C-1 K(b)--K30 with Free-Wheeling Hub and King-Pins LIG H T T R U C K SERVICE M AN U AL 3C-26 FRONT SUSPENSION MAINTENANCE AND ADJUSTMENTS BALL JOINT ADJUSTMENT (K10, K20) Front axle ball joint adjustment is generally necessary only when there is excessive play in steering, irregular wear on tires or persistent loosening of the tie rod is observed. 1. Raise vehicle on hoist then place jack stands just inside of front springs. 2. Disconnect connecting rod and tie rod to allow indepen­ dent movement of each steering knuckle. 3. Apply a fish-scale to the tie rod mounting hole of the steering knuckle arm. With the knuckle assembly in the straight-ahead position, determine the right angle pull required to keep the knuckle assembly turning after initial break-away. This pull should not exceed 25 lbs., for each knuckle assembly, in either direction. See Figure 3C-2K. 4. If the effort exceeds 25 lbs., remove the upper ball stud nut, and loosen the ball stud adjusting sleeve as required. Re-torque the ball stud nut and recheck the turning effort. BEARING LUBRICATION Front Wheel Bearings Spindle Bearings W henever front wheel bearings are lubricated, the spindle needle bearings should also be lubricated, with the same chassis' grease. Under normal conditions, the lubrica­ tion interval should be 12,000 miles; off-road use such as in mud or water will require shorter intervals. The spindle bearings are accessible after removing the spindle, as shown in Figure 3C-6K. WHEEL BEARING ADJUSTMENT 1. After lubricating the wheel bearings and the spindle bearings, install the hub-and-disc, and the outer wheel bearing to the spindle. 2. Torque the inner adjusting nut to 50 foot pounds, (60 N-m) while rotating the hub-and-disc to seat the bearings. Use Tool J-6893 and Adapter J-23446 or J-6893-01 for K10, K20; use J-26878 for K30. Back off the inner adjusting nut and retorque to 35 ft. lbs. (47 N-m) while the hub is being rotated. 3. Back off the inner adjusting nut again 3/8 turn maximum. a. For K10 and K20, assemble the drag sleeve retainer w asher over the axle shaft against the bearing adjusting nut (See Fig. 3C-3K). The tang on the inside diameter of this washer is assembled in the keyway of the spindle. Assemble and tighten the outer lock nut to 217-310 N-m (160-205 lb. ft.). b. For K30, assemble lockwasher and outer locknut. Torque outer locknut to 88 N-m (65 lb. ft.) (mini­ mum). Bend one ear of lockwasher over the inner nut a minimum of 30°. Bend one ear of lockwasher over the outer nut a minimum of 60°. NOTICE: Hub assembly should have .025 to .254 mm (.001 to .010 inch) end play, for all K10, K20 and K30 models. 4. Install the hubs. Refer to hub assembly and installation procedures. Fig. 3C-2K~Determining Front Axle Ball Joint Adjustment LIG H T T R U C K SERVICE M A N U A L FRONT SUSPENSION 3C-27 COMPONENT REPLACEMENT HUB REPLACEMENT NOTICE: See N O T I C E on page 1 of this section, regarding the fasteners in the following procedures for H ub Replacement. AUTOMATIC LOCKING HUBS General Description The Automatic Locking Hub, shown in Fig. 3C-3K, engages or disengages to lock the front axle shaft to the hub of the front wheel. Engagement occurs whenever the vehicle is operated in four-wheel drive. Disengagem ent occurs whenever two-wheel drive has been selected and the vehicle is moved rearward. Disengagement will not occur when the vehicle is moved rearward if four-wheel drive is selected and the hub has already been engaged. The outer clutch housing is splined to the wheel. The hub sleeve is splined to the front axle shaft. The clutch gear is splined to the hub sleeve. Engagement occurs when the clutch gear is moved on the splines of the hub sleeve to engage the internal teeth of the outer clutch housing. The cam surface of the steel inner cage forces the cam follower and clutch gear to move outward toward the cover and into engagement with the clutch teeth of the outer clutch housing. A lug on the inside of the drag sleeve retainer washer keys the washer to the axle and two lock nuts retain this washer in position on the axle. Cutouts in the drag sleeve engage the four tabs on the drag sleeve retainer washer to hold the drag sleeve in a fixed position with respect to the axle shaft. The one way clutch spring (called a brake band) is positioned over the serrated portion of the drag sleeve. Engagement is accomplished (when four-wheel drive is selected) by the movement of the drag sleeve, causing one of the tangs of the brake band to engage the steel outer cage and rotate the cage which will cause the cam ramp to move the clutch gear into mesh with the outer clutch housing. One of the tangs of the brake band is used for engagement when the vehicle is moving forward. The other tang is used to engage reverse when the vehicle is moving rearward. Disengagement is accomplished (when two-wheel drive has been selected) by the reverse movement of the wheel causing the clutch gear, hub sleeve, and cam follower to rotate. The cam follower moves against the lugs of the plastic outer cage, causing the cage to rotate and move to the disengaged condition. The release spring then moves the clutch gear out of mesh with the outer clutch housing to disengage the wheel from the axle shaft. Preliminary Checking Before disassembling a unit for complaint of abnormal noise, read the following: • To obtain all-wheel drive, the transfer case lever must be placed in (4L) o r (4H), at which time the hub locks will automatically engage. • To unlock (free wheel) the hubs, shift the transfer case lever to (2H), th en slowly reverse vehicle direction a p ­ proxim ately ten feet. • Incom plete shift from 2W D to 4WD, or disengagem ent o f only one hub lock may cause an abnorm al sound from the front axle. Shift to 4W D to stop the noise, then unlock the hubs as described above. Removal of Hub from Wheel 1. Remove the five screws ( i t e m # l , Fig. 3C-3K) which retain the cover ( # 3 ) to the outer clutch housing ( # 10). 2. Remove the cover, seal ( # 4 ) , seal bridge ( # 1 1 ) , and bearing components ( # 5 , 6 , 7, 8). 3. Use needle-nose pliers to compress the wire retaining ring ( # 9 ) , and pull the remaining components from the wheel. DISASSEMBLE HUB 1. Remove the snap ring ( # 2 8 ) from the groove of the hub sleeve ( # 1 8 ) . 2. Turn the clutch gear ( # 1 7 ) until it drops into engage­ ment with the outer clutch housing ( # 1 0 ) . Lift and cock the drag sleeve ( # 2 6 ) to unlock the tangs of the brake band ( # 2 5 ) from the window of the inner cage ( # 2 3 ) and remove drag sleeve and brake assembly. It is important that the brake band should never be removed from the drag sleeve. The spring tension of the brake band can be changed if the coils are overexpanded and this could affect the operation of the hub. 3. Remove the snap ring ( # 2 4 ) from the groove in the outer clutch housing. LIG H T T R U C K SERVICE M AN U AL 3C-28 FRONT SUSPENSION 1. M achine Screw 2. Cover Plate 3. Cover 4. Sealing Ring 5. Bearing Race Spring 6 . Bearing Inner Race 7. Bearing 8 . Bearing Retainer Clip 9. W ire Retaining Ring 10. O uter Clutch Housing 1 1. Seal Bridge — Retainer 12. 13. 14. 1 5. 16. 17. 18 . 19. 20. 21. 22. Retaining Ring Spring Support W asher Spring Retainer Return Spring Spring Retainer Clutch G ear Hub Sleeve "C" Type Retaining Ring Conical Spring Cam Follower O uter Cage 23. 24. 25. 26. 27. 28. 29. 30. 31. Inner Cage Snap Ring Brake Band Drag Sleeve and Detent Small Spacer Retaining Ring Lock Nut Drag Sleeve Retainer W asher Adjusting Nut, W heel Bearing Fig. 3C-3K--Automatic Locking Hubs, K10 and K20 LIG H T T R U C K SERVICE M A N U A L FRONT SUSPENSION 4. Use a small screwdriver to pry the plastic outer cage ( # 2 2 ) free from the inner cage ( # 2 3 ) while the inner cage is being removed. 5. Use a small screwdriver to pry the plastic outer cage tabs free from the groove in the outer clutch housing. Remove outer cage. 6. Remove the clutch sleeve ( # 1 8 ) and attached compo­ nents from the outer clutch housing. 7. Compress the return spring ( # 1 5 ) and hold the spring in the compressed condition with fabricated clamps as shown in Fig. 3C-4K. After the clamps are installed, position the entire assembly in a bench vise so that the vise holds both ends of the clutch sleeve. Remove the retaining ring ( # 12). 8. With the clutch sleeve assembly still in the vise, remove the clamps holding the return spring. Slowly open the vise to permit releasing of the retu rn spring in a controlled manner. Remove the retainer seat, spring and spring support washers ( # 1 3 , 14) from the hub sleeve. 9. Remove the C-type retaining ring ( # 1 9 ) from the clutch sleeve. It is necessary to position the sleeve assembly so that the C-ring ends are aligned with the legs of the cam follower, allowing removal between the two legs. 8. The two " C " shaped clamps may be fabricated from 3 /8 " (9.5mm) wide by 3 /3 2 " or 1/8" (2.4-3.2mm) thick stock. The distance between the two legs of the clamps should be approximately 1-1/4" (31.8mm). 9. Place the components assembled in steps 1 through 7 into the outer housing ( # 1 0 ) . The cam follower should be positioned with the two legs directed outboard. 10. Screw three of the cover screws ( # 1) into three holes of the outer clutch housing. These screws will support the component to permit the clutch hub to drop down so that the tangs of brake band ( # 25) may be assembled. 11. Carefully work the plastic outer cage ( # 2 2 ) into the outer clutch housing with the ramps facing toward the cam follower. The small external tabs of the plastic cage should be located in the wide groove of the outer clutch housing. 12. Assemble the steel inner cage ( # 2 3 ) into the outer cage, aligning the tab of the outer cage with the "window" of the inner cage. SHAPED CLAMP "C " 10. Remove the conical spring ( # 2 0 ) from between the cam follower and the clutch gear. 11. Separate the cam follower ( # 2 1 ) from the clutch gear (#17). REASSEMBLE HUB 1. Snap the tangs of the cam follower ( # 2 1 ) over the flats of the clutch gear ( # 1 7 ) . 2. Compress the conical spring ( # 2 0 ) and slide it into position with the large diameter of the spring located against the clutch gear. 3. Position the clutch gear assembly over the splines of the hub sleeve ( ( # 1 8 ) . The teeth of the cam follower should be located at the end of the hub sleeve which has no splines. The clutch gear and spring should slide freely over the splines of the hub sleeve. 4. Assemble the " C " shaped retainer ring ( # 1 9 ) in the groove of the hub sleeve. RETAINING RING 5. Assemble a spring retainer ( # 1 4 , 16) over each end of the return spring ( # 1 5 ) . 6. Position one end of the return spring with retainer ( # 1 6 ) against the shoulder of the clutch gear. 7. Place the spring support washer ( # 1 3 ) against the retainer on the end of the return spring. Compress the return spring and assemble the retainer ring ( # 1 2 ) in the groove of the hub sleeve. Two " C " shaped clamps may be used to retain the return spring while the retainer ring is being assembled. Refer to Fig. 3C-3K. 3C-29 Fig. 3C-4K--Using Clamp and Vise to Compress Return Spring 3C-30 FRONT SUSPENSION 13. Assemble the retaining ring ( # 2 4 ) into the groove of the outer clutch housing above the outer cage. 14. The brake band and drag sleeve are serviced as an assembly. 15. Assemble one of the two tangs of the brake band ( # 2 5 ) on each side of the lug of the outer cage which is located in the window of the steel inner cage. It will be necessary to cock these parts to engage the tangs in this position as the drag sleeve is positioned against the face of the cam follower. 16. Remove the three screws and rest the end of the hub sleeve on a suitable support. Assemble the washer ( # 27) and snap ring ( # 28) above the drag sleeve. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. The following steps may be completed as hub is assembled to vehicle. Assemble the wire retaining ring ( # 9 ) in the groove in the unsplined end of the outer clutch housing. The tangs of the retainer ring should point away from the splined end of the clutch housing. Hold the tangs of the wire retainer together and assemble the two bent down tabs of the seal bridge ( # 1 1 ) over the tangs. The seal bridge holds the wire retainer ring in a clamped condition in the groove of the outer clutch housing. Assemble the " O " ring in the groove of the outer clutch housing and over seal bridge. Assemble the bearing ( # 7 ) over the inner race ( # 6 ) . Lubricate the bearing as it is assembled with light wheel bearing grease. The steel balls should be visible when bearing is properly assembled. Snap the bearing retainer clip ( # 8 ) into the hole in the outer race. Assemble the bearing and retainer assembly in the end of the hub sleeve. Assemble the seal ring ( # 4 ) over the outer clutch housing. Assemble the bearing race spring ( # 5 ) into the bore in the cover. Assemble the cover and spring assembly. Align the hole in the cover to the holes in the outer clutch housing and assemble the five screws. Assemble the O-ring over the seal bridge to prevent it from jumping out of position during handling prior to the hub bearing assembled to the vehicle. This " O " ring may be left on but is not required. The hub sleeve and attached parts should turn freely after the unit has been completely assembled. The five cover screws must be loosened to assemble the hub to the vehicle. Torque these screws after hub is installed to 4.5-5.6 N-m (40-50 in-lbs.). Assemble New Hub to Wheel 27. A drag sleeve retainer washer ( # 3 0 ) is supplied with each new assembly. Assemble this washer between the wheel bearing adjustment nut and the lock nut. Adjust the inner nut to give proper bearing adjustment. 28. Use J-6893 to torque adjusting nut ( # 3 1 ) to 60 N-m (50 ft. lbs.), to seat the bearings; then, back off the nut and torque to 47 N-m (35 ft. lbs.) while the hub is being rotated. Finally, back the adjusting nut off a maximum of 3/8 turn. Assemble the drag sleeve retainer washer LIG H T T R U C K SERVIC E M AN U AL over the axle shaft against the bearing adjustment nut. The tang on the inside diameter of this washer is assembled in the keyway of the axle shaft. Assemble and tighten the outer lock nut to 217-310 N-m (160205 lb-ft). 29. Align the cut-outs in the drag sleeve with tabs on the drag sleeve washer as the splines of the outer clutch housing are assembled into splines of the hub of the wheel. Loosen the cover screws three or four turns and push in on these screws, to allow the retaining ring to expand into groove in hub of wheel as the seal bridge is forced from position over the retaining ring as the tang of seal bridge contacts wheel hub. Torque the cover screws to 4.5-5.6 N-m (40-50 lb. in.) Assemble a Rebuilt Hub to Wheel 30. Steps 1-17 in the assemble procedure are usually completed whenever the hub is rebuilt and then assembled to the wheel. 31. Hold the two tangs of the retaining ring in the clamped condition as the assembled components are assembled to the hub of the wheel. See step 29 for installation of drag sleeve washer. 32. Assemble the seal bridge in the cut-out of the outer clutch housing. Assemble the sealing ring over the outer clutch housing. 33. Assemble the bearing and retainer assembly into the hub sleeve. 34. Assemble the bearing race spring to the cover. 35. Assemble the cover and cover bolts. Tighten cover screws to 4.5-5.6 N-m (40-50 lb. in.). FREE-WHEELING HUBS K30 (Fig. 3C-5K) Hub Removal 1. Turn actuator lever to set hub to "L O C K " position (Fig. 3C-5K) and raise vehicle on hoist. Rotate tire to assure that hub lock is engaged. 2. Remove six retaining plate bolts and remove retaining plate, actuating knob, and " O " ring. 3. Remove internal snap ring, outer clutch retaining ring, a c tuating cam body, outer clutch gear, and clutch spring. 4. Relieve pressure on the axle shaft snap ring and remove snap ring. 5. Remove the inner clutch gear. 6. Remove spring retainer plate. 7. Remove the wheel bearing outer lock nut, lock ring, and wheel bearing inner adjusting nut using Tool J-6893 and Adapter J-23446 or Tool J-6893-01. 8. Remove the hub-and-disc assembly, outer wheel bear­ ing and the spring retainer plate. a. Remove the oil seal and inner bearing cone from the hub using a brass drift and tapping with a hammer. Discard the oil seal. b. Remove the inner and outer bearing cups using a brass drift and hammer. c. Clean, inspect and lubricate all parts as required. FRONT SUSPENSION 1. 2. 3. 4. 5. 6. 7. RETAINING PLATE BOLTS WASHER HUB RING RETAINING KNOB ACTUATOR KNOB " 0 " RING ACTUATOR KNOB " 0 " RING INTERNAL SNAP RING 8. 9. 10. 11. 12. 13. 14. 3C-31 OUTER CLUTCH RETAINING RING ACTUATING CAM BODY AXLE SHAFT SNAP RING AXLE SHAFT SLEEVE AND RING INNER CLUTCH RING PRESSURE SPRING SPRING RETAINER PLATE Fig. 3C-5K--Free-Wheeling Hub-Explode 3C-32 FRONT SUSPENSION Installation of Hub 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. NOTICE: All parts should be lubricated for normal operation during assembly with an ample amount of high speed grease. Lubrication M U S T be applied to prevent deterioration before the unit is placed in service. Assemble the outer wheel bearing cup into the wheel hub using Installer J-6368 and Driver Handle J-8092. Assemble the inner wheel bearing cup into the wheel hub using Installer J-23448 and Driver Handle J-8092. Pack the wheel bearing cone with a high melting point type wheel bearing grease and insert the cone into the cup. After lubricating the wheel bearings, install the huband-disc and the bearings to the spindle. Adjust wheel bearings as listed in "M aintenance and A djustm ents". Install inner clutch gear onto the axle shaft. Press in on inner clutch gear and install axle shaft snap ring on inboard groove. Install pressure spring into position. Large O.D. seats against wheel bearing. Install outer clutch gear, actuating cam body (cams facing outw ard), outer clutch retaining ring and internal snap ring. Install " O " ring on retaining plate and install actuat­ ing knob and retaining plate. Install actuating knob with knob in " L O C K " position-grooves in knob must fit into actuator cam body. Install six cover bolts and seals, and torque to 35-40 in. lbs. Turn knob to " F R E E " position to check for proper operation. Lower vehicle to floor. Servicing Spindle Components When servicing the spindle check the spindle grease seals (Fig. 7K). 1. Secure the spindle in a vise by locating on the high step diameter. Be sure that the machined surface of the spindle will not be damaged by the vise jaws. 2. Remove the oil seal. 3. Remove the needle roller bearing. 4. Place the spindle in a vise on the high step and install needle roller bearing. a. Use J-23445 and Drive H andle J-8092 for K 10, K20. b. Use J-21465-17 for K-30. 5. Install grease seal onto slinger with lip toward spindle. 6. Relubricate the needle bearing and the spindle end with a high melting point type wheel bearing grease. Installation 1. Install the bronze thrust washer over the axle shaft with the chamfer toward the slinger and install the spindle as shown in Figure 3C-8K. 2. Assemble spindle to knuckle. Use new spindle nuts and torque to 88 N-m (65 lb. ft.). NOTICE: See N O T IC E on page 1 of this section. SPINDLE Removal 1. Remove the hub-and-disc assembly as outlined earlier. 2. Remove the spindle retaining bolts. 3. Remove the spindle and bronze thrust washer by tapping the end of the spindle lightly with a soft hammer to break it loose from the knuckle as shown in Figure 3C-6K. Replace the thrust washer if excessive wear has occurred. L IG H T T R U C K SERVICE M AN U AL Fig. 3C-6K~Removing Spindle and Thrust Washer FRONT SUSPENSION 3C-33 Fig. 3C-7K--Front Spindle Grease Seals KNUCKLE K10, K20, (WITH BALL JOINTS) Removal 1. Remove hub and spindle components as outlined earlier. 2. If the steering arm is to be removed, disconnect the tie rod. a. Remove cotter pin. b. Loosen tie rod nuts and tap on nut with a soft ham mer to break the studs loose from the knuckle arm. c. Remove nuts and disconnect the tie rod. If it is necessary to remove the steering arm, discard the self-locking nuts (Fig. 3C-9K) and replace with new nuts at assembly. 3. Remove the cotter pin from the upper ball socket nut. 4. Remove the retaining nuts from the upper and lower ball sockets as shown in Figure 3C-10K. L IG H T T R U C K SERVIC E M AN U AL 3C-34 FRONT SUSPENSION J-23454-1 l Fig. 3C-8K--lnstalling Spindle and Thrust Washer Fig. 3C-11 K--Removing Lower Ball Joint Ball Joint Service NOTICE: Do not remove the yoke upper ball stud adjusting sleeve unless new ball studs are being in­ stalled. If it is necessary to loosen the sleeve to remove the knuckle, do not loosen it more than two threads using Spanner J-23447 as shown in Figure 3C-15K. The nonhardened threads in the yoke can be easily damaged by the hardened threads in the adjusting sleeve if caution is not used during knuckle removal. • On the LH knuckle, it is necessary to remove the steering arm before servicing the upper ball joint. Fig. 3C-9K--Removing Steering Arm Nuts 5. Remove the knuckle assembly from the yoke by inserting a suitable wedge-shaped tool between the lower ball stud and the yoke and tapping on the tool to release the knuckle assembly. Repeat as required at the upper ball stud location. Remove the lower ball joint snap ring before beginning. Lower ball joint must be removed before any service can be performed on the upper ball joint. 1. Remove the lower ball joint using tools J - 9 5 19-10, J-23454-1, and sleeve J-23454-4 or equivalent as shown in Figure 3 C -1 1K. If Tool J-23454-4 is not available, a suitable tool may be fabricated from 2-3/8" O.D. steel tubing with a minimum of 2-1/16" I.D., cut 63.50mm (2 -1 /2 ") long. Fig. 3C-12K--Removing Upper Ball Joint LIG H T T R U C K SE RV IC E M A N U A L FRONT SUSPENSION 3C-35 J -6 3 8 2 -3 OR J -2 3 4 5 4 -3 J-2 3 4 4 7 BALL J O IN T J -2 3 4 5 4 -2 Fig. 3C-13K—Installing Lower Ball Joint 2. Remove Lhe upper ball joint using tools J-9519-10, J-23454-1, and sleeve J-23454-4 or equivalent as shown in Figure 3C-12K. 3. Install the lower ball joint into the knuckle. Make sure that the lower ball joint (the joint without cotter pin hole in the stud end) is straight. Press the stud into the knuckle until properly seated using tools J-9519-10, J-23454-2, and J-23454-4 or equivalent as shown in Figure 3C-13K and install snap ring. 4. Install the upper ball joint into the knuckle. Press the stud into the knuckle until properly seated using Tools J-9519-10, J-23454-2, and J-23454-4 or equivalent as shown in Figure 3C-14K. Fig. 3C-15K--Ball Stud Adjusting Sleeve 3. Torque the yoke upper ball stud adjusting sleeve to 70 N-m (50 ft. lbs.) using Spanner J-23447. See Figure 3C-15K. Installation NOTICE: See N O T I C E on page 1 of this section regarding the fasteners in the following steps. 1. Position the knuckle and sockets to the yoke. Install new nuts finger tight to the upper (the nut with the cotter pin slot) and lower ball socket studs. 2. Push up on the knuckle (to keep the ball socket from turning in the knuckle) while tightening the lower socket retaining nut. Torque lower nut to 95 N-m (70 ft. lbs.). Fig. 3C-16K--Torquing U p per Ball Socket Nut BALL JO IN T J -2 3 4 5 4 -2 J-6382-3 OR J-23454-3 J-9519-10 Fig. 3C-14K—Installing Upper Ball Joint Fig. 3C-17K--Removing Spindle L IG H T T R U C K SE RV IC E M AN U AL 3C-36 FRONT SUSPENSION Fig. 3C-18K~Removing Nuts Alternately 4. Torque the upper ball socket nut to 100 ft. lbs. as shown in Figure 3 C -16K. After torquing the nut, do not loosen to install cotter pin, apply additional torque, if neces­ sary, to line up hole in stud with slot in nut. 5. If the tie rod and steering arm were removed: a. Assemble the steering arm using the three stud adapters and three new self-locking nuts. Torque the nuts to 120 N-m (90 ft. lbs.). b. Assemble the tie rod to the knuckle arm. Torque the tie rod nuts to 60 N-m (45 ft. lbs.) and install cotter pin. KNUCKLE K30 (WITH KING PINS) Removal 1. Remove the hub and spindle as outlined earlier. If necessary, tap lightly with a rawhide ham mer to free it from the knuckle. Check bronze spacer located between axle shaft joint assembly and bearing. If wear is evident, replace with a new one. See Figure 3C-17K. Fig. 3C-19K--Removing Cap, Spring and Gasket L IG H T T R U C K SERVIC E MANUAL Fig. 3C-20K--Removing Lower Bearing Cap 2. Remove four nuts from upper king pin cap. Remove nuts alternately as compression spring will force cap up. Refer to Figure 3C-18K. 3. Remove cap, compression spring, and gasket, as shown in Figure 3C-19K. Discard gasket, replace with new one at time of assembly. 4. From the underside of the knuckle, remove four cap screws from the lower king pin bearing cap. Remove the bearing cap-and-lower king pin. See Figure 3C20K. 5. Remove upper king pin tapered bushing and knuckle from yoke. Remove king-pin felt seal. See Figure 3C21K. Remove knuckle. 6. Remove upper king-pin from yoke with large breaker bar and J-2 6 8 7 1, as seen in Figure 3C-22K. Torque specification is 677.50-813.00 N-m (500-600 ft. lbs.). 7. Remove lower king pin bearing cup, cone, grease retainer, and seal all at the same time, as shown in Figure 3C-23K. Discard seal and replace with new one at time of assembly. If grease retainer is damaged, replace with new one at time of assembly. Fig. 3C-21 K--Removing Tapered Bushing FRONT SUSPENSION Fig. 3C-22K--Removing Upper King Pin 3C-37 Fig. 3C-24K--lnstalling Grease Retainer Installation See the N O T I C E on page 1 of this section regarding the fasteners in the following steps. NOTICE: 1. Assemble new grease retainer and lower king pin bearing cup, using J - 7 8 17, as shown in Figure 3C-24K. 2. Fill the area in grease retainer with specified grease, then grease the bearing cone and install. Install new lower king pin bearing oil seal, using J-2 22 81, as shown in Figure 3C-25K. Do not distort oil seal. It will protrude slightly from the surface of yoke flange when fully installed. 3. Install upper king-pin, using J-28871 as shown in Figure 3C-26K. Torque to 677.50-813.00 N-m (500600 ft. lbs.). 4. Assemble felt seal to king pin, assemble knuckle, assemble tapered bushing over king pin, as shown in Figure 3C-27K. 5. Assemble lower bearing cap-and-king pin with four cap screws. Tighten cap screws alternately and evenly; see Figure 3C-28K. Torque cap screws to 95-120 N-m (7090 ft. lbs.). Fig. 3C-23K--Removing Cup, Cone and Seal Fig. 3C-25K--lnstalling Oil Seal 6. Assemble compression spring on upper king pin bush­ ing. Assemble bearing cap, with new gasket, over four studs. Tighten nuts alternately and evenly. Torque nuts to 95-120 N-m (70-90 lb. ft.) See Figure 3C-29K. Fig. 3C-26K--lnstalling Upper King-Pin LIG H T T R U C K SE RV IC E M ANUAL 3C-38 FRONT SUSPENSION Fig. 3C-27K--lnstalling Knuckle to Yoke Fig. 3C-30K--Shock Absorber Attachment SHOCK ABSORBER Removal (Fig. 3C-30K) 1. Raise vehicle on hoist. 2. Remove nuts and eye bolts securing upper and lower shock absorber eyes. 3. W ith draw shock absorber and inspect rubber eye bushings. If defective, replace shock absorber assembly. Installation Place shock absorber into position over mounting bolts or into mounting brackets. Install eye bolts and nuts and torque as shown in Specifications Section. Lower vehicle to floor. STABILIZER BAR-TYPICAL Removal (Fig. 3C-31K) Fig. 3C-28K--lnstalling Lower Bearing Cap-and-King Pin 1. Raise vehicle on hoist and remove nuts and bolts attaching stabilizer brackets and bushings at frame location. 2. Remove brackets and bushings at lower spring anchor plates and remove stabilizer from vehicle. TYPICAL L.&R.H. VIEW A SPRING PLATE TYPICAL L &R.H. VIEW B Fig. 3C-29K--lnstalling Bearing Cap/Steering Arm LIG H T T R U C K SERVICE M A N U A L Fig. 3C-31 K--Stabilizer Bar Attachment FRONT SUSPENSION 3C-39 Inspection Inspect rubber rushings for excessive wear or agingreplace where necessary. Use rubber lubricant when install­ ing bushings over stabilizer bar. Installation NOTICE: See N O T I C E on page 1 of this section regarding the fasteners referred to in step 2. Slit in bar to frame bushings should be facing forward. 1. Place stabilizer in position on frame and install frame brackets over bushings. Install nuts and bolts loosely. 2. Install brackets over bushings at lower control arm location. Be sure brackets are positioned properly over bushings. Torque all nuts and bolts to specifications. 3. Lower vehicle to floor. LEAF SPRING AND BUSHINGS (Figs. 3C-32K and 3C-33K) Removal 1. 2. 3. 4. 5. 6. Raise vehicle on hoist. Place adjustable lifting device under axle. Position axle so that all tension is relieved from spring. Remove shackle upper retaining bolt. Remove front spring eye bolt. Remove spring-to-axle u-bolt nuts and remove spring, lower plate and spring pads. 7. Remove shackle to spring bolt and remove bushings and shackle. 2. Press in new bushing; assure that tool presses on steel outer shell of bushing. Install until bushing protrudes an equal am ount on each side of spring. Spring Inserts (Liners) or Leaf Replacement 1. Place spring in vise and remove clips. 2. Remove center bolt. Open vise slowly, allowing spring to expand. 3. Wire brush, clean, and inspect for broken leaves. 4. Replace leaf or liners. Installation NOTICE: See N O T IC E on page one of this section regarding the fasteners referred to in steps 5 and 6. 1. Install spring shackle bushings into spring and attach shackle. Do not tighten bolt. 2. Position spring upper cushion on spring. 3. Insert front of spring into frame and install bolt. Do not tighten. 4. Install shackle bushings into frame and attach rear shackle. Do not tighten bolt. 5. Install lower spring pad and spring retainer plate. Torque bolts to specifications, Fig. 3C-35. 6. Torque front and rear spring eye and shackle bolts to specifications. 7. Remove stands and lower vehicle to floor. Bushing Replacement 1. Place spring on press and press out bushing using a suitable rod, pipe, or tool. TIG H TE N IN G SEQUENCE 1. 2. 3. Install all four nuts to uniform engagement on 'U ' Bolts to retain and position anchor plate in design position (perpendicular to axis of 'U ' Bolts). Torque nuts in positions 1 and 3 to 10-25 ft. lbs. (14-34 N-m). Torque all nuts to full torque in follow ing sequence: 2-4-1-3. 1 Fig. 3C-33K--U-Bolt Tightening Sequence LIG H T T R U C K SE RV IC E M AN U AL 3C-40 FRONT SUSPENSION SPECIFICATIONS FRONT SUSPENSION BOLT TORQUE (ft. lbs.) * t CP-10 CP-20-30 K-AII G-10-20 Lower Control Arm Shaft U-Bolt 85 85 — 65 85 Upper Control Arm Shaft Nuts 70 105 — 70 105 Control Arm Rubber Bushings 115 — New 190 — 115 Upper Control Arm Bushing Steel t t — — — — **10 0 ***8 0 * 50 **9 0 Used 115 New Lower Control Arm Bushing Steel t t 280 Used 130 Upper Ball Joint Nut Lower Ball Joint Nut * 50 **9 0 Nut, Spindle-to-Knuckle **9 0 **90 G-30 — N ew 190 Used 115 N ew 280 Used 130 **9 0 **9 0 — — — — • 65 65 — 65 65 •• 90 90 — 90 90 Crossmember Brake Support Struts 60 60 60 60 Crossmember to Side Rail Crossm ember to Bottom Rail Stabilizer Bar to Control Arm 25 Stabilizer Bar to Frame Anchor Plate — 130 25 25 25 .55 25 140 140 65 75 60 120 in. lbs. 60 120 in. lbs. — — .001-.005” 35 .001-.005” 35 .001-.010” — .001-.005” 35 — Shock Absorber Upper End Shock Absorber Lower End Brake Splash Shield to Knuckle 25 65 Wheel Bearing Adjustment Wheel Bearing End Movem ent Caliper Mounting Bolt 65 120 in. lbs. Inner 35 Outer • • • 75 120 in. lbs. — Spring — Front Eye Bolt — — 90 Spring — Rear Eye Bolt — — 50 — Spring — To Rear Shackle Bolt Spring — To Axle U-Bolt — — — — 50 150 — — Spring — Front Support to Frame — — 25 — Suspension Bumper 15 15 Stabilizer to Spring Plate — — 25 130 — * ** *** t tt • •• ••• Plus additional torque to align cotter pin. Not to exceed 90 ft. lbs. maximum. Plus additional torque to align cotter pin. Not to exceed 130 ft. lbs. maximum. Plus additional torque to align cotter pin. All specifications are given in foot pounds of Torque unless indicated otherwise, C10, G10-20 Rubber Bushings; C20-30, P10-30 Steel Bushings. P300 (32), P300 (42) and JF9 — 100 ft. lbs. P300 (32) — 215 ft. lbs., P300 (42) and JF9 — 130 ft. lbs. (K10-20) 205 ft. lbs., (K30) 65 ft. lbs. Specs Page LIG H T TR U C K SE R V IC E M AN U AL 15 FRONT SUSPENSION 3C-41 SPECIAL TOOLS 1. 2. 3. 4. 5. J-8457 J-8458 J-8849 J-9276-2 J-24435-1 thru 7 Bearing Bearing Bearing Bearing Bushing C 10, G Race Installer Race Installer Race Installer Race Installer Replacement 10-20 6. 7. 8. 9. 10. 11. J-8092 J-9519-9 J-9519-7 J-9519-10 J-23028-01 J-23742-1 Driver Handle Ball Joint Installer Ball Joint Remover " C " Clamp Spring Remover Ball Joint Remover Fig. 3C-ST--Special Tools LIGHT TRUCK SERVICE MANUAL REAR SUSPENSION 3D-1 SECTION 3D REAR SUSPENSION The following notice applies to one or more steps in the assembly procedure of components in this portion of the manual as indicated at the appropriate locations by the terminology "See Notice on page 1 of this Section ". N OTICE This fastener is an important attaching part in that it could affect the performance of vital components and systems, and /o r could result in major repair expense. It must be replaced with one of the same part number or with an equivalent part if replacement becomes necessary. Do not use a replacement part of lesser quality or substitute design. Torque values must be used as specified during reassembly to assure proper retention of this part. INDEX General D escription......................................................................................... ..3D-1 Component Parts R ep lacem en t.......................................................................3D-2 Shock Absorbers..............................................................................................3D-2 Stabilizer S h a f t ............................................................................................. ..3D-3 Leaf Spring Assembly................................................................................. ..3D-4 Specifications...................................................................................................... ..3D-10 GENERAL DESCRIPTION All 10-30 series vehicles use a leaf spring/solid rear axle suspension system. Typical systems are illustrated in Fig. 3D-1, 3D-2 and 3D-3. The rear axle assembly is attached to multi-leaf springs by " U " bolts. The spring front eyes are attached to the frame at the front hangers, through rubber bushings. The rear ends of the springs are attached to the frame by the use of shackles which allow the spring to "change its length" while the vehicle is in motion. Control arms are not required with leaf springs. Ride control is provided by two identical direct double acting shock absorbers angle-mounted between the frame and brackets attached to the axle tubes. LIG H T T R U C K SE R V IC E M AN U AL 3D-2 REAR SUSPENSION Fig. 3D-2--Typical G-Truck Rear Suspension Fig. 3D-3--Typical P-30 H.D. Truck Rear Suspension COMPONENT PARTS REPLACEMENT SHOCK ABSORBERS 5. To install shock absorber, place into position and reattach at upper mounting location. Be sure to install nuts and washers as shown. Replacement Refer to Figs. 3D-4 through 3D-8 for specific vehicle mounting provisions. 1. Raise vehicle on hoist, and support rear axle. 2. At the upper m ounting location, disconnect shock absorber by removing nut and washers shown, and bolt on G-models. 3. At the lower mounting location, remove nut, washers and bolt as shown. 4. Remove shock absorbers from vehicle. Fig. 3D-4--Shock Absorber-CK-10, CK-20 (03, 06) LIG H T TR U C K SE RV IC E M A N U A L 6. Align lower end of shock absorber with axle bracket, and install bolt, washers and nut, as shown. 7. Tighten nuts to specifications. NOTICE: See N O T I C E on page 1 of this section regarding shock absorber fasteners. 8. Lower vehicle and remove from hoist. Fig. 3D-5~Shock Absorber-CK-20 (43), CK30 REAR SUSPENSION 3D-3 Fig. 3D-8--Shock Absorber-P30 STABILIZER SHAFTS Refer to Fig. 3D-9, 3D-10 and 3D -11 for specific rear stabilizer shaft mounting on C and P models. Replacement 1. Raise vehicle on hoist and support rear axle. 2. Remove nut, washer and grommet from link bolt at the frame side member on each side. 3. W ithdraw link bolt, washers, grommets and spacer. 4. Remove brackets from anchor plates by removing attaching screws. 5. Remove stabilizer shafts. 6. Reverse above steps to install stabilizer shaft. On installation, position shaft so parking brake cable is routed over stabilizer. 7. Torque all bolts to specifications. NOTICE: See N O T I C E on page 1 of this section, regarding stablizer fasteners. 8. Lower hoist and remove vehicle. Fig. 3D-9--Rear Stabilizer Shaft-C-20(03) LIGHT TRUCK SERVICE MANUAL 3D-4 REAR SUSPENSION SPACER GROMMET SHAFT P300(32) LINK BOLT ANCHOR PLATE NOTE T orqu e by running nut to unthreaded portion of bolt. Fig. 3D-10--Rear Stabilizer Shaft-C-20(43), C-30 LEAF SPRING ASSEMBLY Refer to Figs. 3D-12 - 3D-21 for specific leaf spring mounting provisions of C, K, G and P models. Fig. 3D-22 illustrates a typical U-bolt anchor plate installation with the mandatory tightening sequence. NOTICE: See N O T I C E on page 1 of this section, regarding leaf spring fasteners. Removal 1. Raise vehicle on hoist so that load in spring is relieved. 2. Loosen, but do not remove, spring-to-shackle retaining nut. 3. Remove nut and bolt securing shackle to spring hanger. 4. Remove nut and bolt securing spring to front hanger. 5. Remove " U " bolt retaining nuts, withdraw " U " bolts and spring plate from spring-to-axle housing attachment. 6. W ithdraw spring from vehicle. 7. Inspect spring. Replace bushings, repair or replace spring unit as outlined in this section. Bushing Replacement 1. Place spring on press and press out bushing using a suitable rod, pipe or tool as shown in Fig. 3D-21. 2. Press in new bushing; assure that tool presses on steel outer shell of bushing. R ear Spring, Front Eye-Heavy Duty leaf springs on C20, CK30, and some P30 trucks use a staked- in-place flanged front eye bushing. Before this bushing is pressed out of the spring, the staked locations must be straightened with a chisel or drift. After a new bushing is installed, it must be staked in three equally spaced locations. LIG H T T R U C K SERVICE M A N U A L P300(42) Fig. 3D-11--Rear Stabilizer Shaft-P30 Spring Leaf Replacement 1. Place spring assembly in a bench mounted vise and remove spring clips or pry clips open. 2. Position spring in vise jaws, compressing leaves at center and adjacent to center bolt. 3. File peened end of center bolt and remove nut. Open vise slowly to allow spring assembly to expand. 4. Wire brush and clean spring leaves. Inspect spring leaves to determine if replacement is required; also replace defective spring leaf liners at this time. 5. Align center holes in spring leaves by means of a long drift and compress spring leaves in a vise. 6. Remove drift from center hole and install a new center bolt. Tighten nut and peen bolt to retain nut. 7. Align spring leaves by tapping with hammer, then reinstall alignment clips. Spring clips should be bent sufficiently to maintain alignment, but not tight enough to bind spring action. REAR SUSPENSION 3D-5 G 1 0 0 + 2 0 0 ( 0 5 + 0 6 ) ALL G 3 0 0 ( 0 5 + 0 6 ) ex c G 50 C 3 0 0 (0 5 + 0 6 ) & G 50 Fig. 3D-12--Rear Spring Hangers And Installation-G Models Leaf Spring Installation 1. Clean axle spring pad and position spring assembly to axle. Position spring to insure clearance to hangers. The shackle assembly must be attached to the rear spring eye before installing shackle to rear hanger Fig. 3D-13~Rear Spring Installation - G Models (Cutaway Vans) shackle m ust be positioned with arrow pointing forward. 2. Install spring retainer plate and " U " bolts. Loosely install retaining nuts evenly, but do not torque at this time. Fig. 3D-14--Rear Spring Hangers - G Models (Cutaway Vans) L IG H T T R U C K SE RV IC E M AN U AL 3D-6 REAR SUSPENSION 3. Jack frame as required to align spring and shackle with spring hangers. 4. Install shackle bolt and nut and again reposition spring, if necessary to align front eye. Install front eye bolt and nut. Torque hanger and shackle nuts to specifications. Make certain that the bolts are free-turning in their bushings prior to torquing. 5. Lower vehicle so that weight of vehicle is on suspension components and torque U-bolt nuts to specifications. 6. Lower vehicle and remove from hoist. U-Bolt and Anchor Plate Installation Fig. 3D-23 illustrates the m a n d ato ry sequence of tightening U-bolt nuts. Tighten diagonally opposite nuts to 40-50 foot pounds, then tighten all nuts as shown to specifications. Fig. 3D-15--Rear Spring Hangers-G Models (Cutaway Vans) NOTICE: See N O T I C E on page 1 of this section, regarding "U " -B o lt fasteners. SHACKLE REPLACEMENT 1. Raise vehicle on hoist. Place adjustable lifting device under axle. 2. Remove load from spring by jacking frame. 3. Loosen spring-to-shackle retaining bolt, but do not remove. 4. Remove shackle-to-frame bracket retaining bolt then remove shackle bolt from spring eye. 5. Position shackle to spring eye and loosely install retaining bolt. Do not torque retaining bolt at this time. 6. Position shackle to frame bracket and install retaining bolt. Arrow stamped on shackle must point forward. 7. Rest vehicle weight on suspension components and torque both shackle bolt retaining nuts to specifications. NOTICE: See N O T I C E on page 1 of this section, regarding these fasteners. Fig. 3D-16--Rear SPring Installation - G MOdels (Cutaway Vans) LIG H T T R U C K SERVICE M A N U A L 8. Lower vehicle and remove from hoist. REAR SUSPENSION 3D-7 Fig. 3D-17--Rear Spring Installation-C-K Models LIGHT TRUCK SERVICE MANUAL 3D-8 REAR SUSPENSION Fig. 3D-20--Rear Spring Installation-P 10,20 Fig. 3D-21--Rear Spring lnstallation-P30 LIG H T T R U C K SE RV IC E M A N U A L REAR SUSPENSION 3D-9 1. Install all four nuts to uniform engagement on 'U' Bolts to retain and position anchor plate in design position (perpendicular to axis of 'U ' Bolts). 2. Torque all nuts in a diagonal sequence (e.g . 1-3-2-4) to 14-35 N.m. 3. Torque all nuts to full torque using a diagonal sequence. Fig. 3D-22--Pressing Out Bushing Fig. 3D-23--U-Bolt Installation L IG H T T R U C K SERVICE M A N U A L 3D-10 REAR SUSPENSION SPECIFICATIONS TORQUE SPECIFICATION Spring-to-Axle "U " Bolt Nuts C-K G 140 G10 120 P10 140 G20 120 P20 140 G30 150 P30 170 (Exc. W /3 /4 " Bolt) P 200 (W /3 /4 " Bolt) Leaf Spring — Front Bushing Bolt 90/135* 110 110 (G316 . . .90) — Rear Shackle Bolt 90/135* 110 110 (G316 . . .90) Shock Absorber — Upper Attachment 150 75 P10 25 P20 140 P30 50 — Lower Attachment 115 75 115 To Rear Axle (Strap) 12-17 12-17 12-17 To Rear Axle ("U " Bolt) 18-22 18-22 18-22 Bearing Support-to-Hanger 20-30 20-30 20-30 Hanger-to-Frame 40-50 — — 20-30 — 20-30 Propeller Shaft Rear Stabilizer-to-Anchor Plate *9 0 Ft. Lbs. when tightening the nut. 135 Ft. Lbs. when tightening the bolt. --Specifications LIGHT TRUCK SERVICE MANUAL WHEELS AND TIRES 3E-1 SECTION 3E WHEELS AND TIRES NOTICE: The Wheel bolt and nut fasteners are an important attaching part in that they could affect the performance of vital components and systems, and /o r could result in major repair expense. They must be replaced with one of the same part number or with an equivalent part if replacement becomes necessary. Do not use a replacement part of lesser quality or substitute design. Torque values must be used as specified during reassembly to assure proper retention of this part. INDEX General Description.............................................................3E-1 Replacement T ire s.............................................................3E-1 Metric T ir e s ....................................................................... .3E-2 Replacement W h e e ls....................................................... .3E-2 Certification L ab el.............................................................3E-3 Service O perations.............................................................. .3E-3 Tire Inspection and R o ta tio n ........................................ .3E-3 Tire Inflation Pressure......................................................3E-4 Correcting Irregular Tire W e a r .....................................3E-7 Wheel Installation .............................................................3E-8 Tire Mounting and D em ounting.................................. .3E-9 Tire R epair......................................................................... .3E-10 Wheel N u t T orqu es......................................................... .3E-10 GENERAL DESCRIPTION The factory installed tires and wheels are designed to operate satisfactorily with loads up to and including the full rated load capacity when inflated to the recommedned inflation pressures. Correct tire pressures and driving techniques have an important influence on tire life. Heavy cornering, exces­ sively rapid acceleration, and unnecessary sharp braking increase tire wear. REPLACEMENT TIRES CAUTION:Do not mix different types of tires on the same vehicle such as radial, bias, and bias-belted tires except in emergencies, because vehicle handling may be seriously affected and may result in loss of control. Some truck-type tires and most passenger-car-type radial tires have a T P C Spec. No. (T ire Perform ance Criteria Specification Num ber) molded into the tire side­ wall near the tire size marking. This shows that the tire meets rigid size and performance standards which were developed for the vehicle. The TPC Spec. No. assures a proper combination of endurance, load capacity, handling, and traction on wet, dry and snow covered surfaces. When replacing tires with tires having the same TPC Spec. No., tires will be compatible with the vehicle. When replacing tires with those not having a TPC spec, use the same size, load range, and construction type (bias, bias-belted, or radial) as the original tires on the vehicle (see the Certifica­ tion Label Fig. 3E-3). Use of any other size or type tire may affect load carrying capacity, ride, handling, speedometer/ odometer calibration, vehicle ground clearance, and tire clearance to the body and chassis. If replacing only a single tire, it should be paired on the same axle with the least worn tire of the others. All tires on four-wheel drive vehicles must be of equal size (but not necessarily ply rating) and of same tread configuration. Replace tires when: 1. Tires are worn to a point where 2/32 inch (1.6 millimetres) or less tread remains, or the cord or fabric is exposed. To help detect this, tires have built-in tread wear indicators (Fig. 3E-2) that appear between the tread grooves when the tread depth is 2/32 inch (1.6mm) or less. When the indicators appear in two or more adjacent grooves at three spots around the tire, the tire should be replaced. 2. Tire thread or sidewall is cracked, but, or snagged deep enough to expose the cord or fabric. 3. Tire has a bump, bulge, or split. 4. Tire sustains a puncture, cut, or other injury that can’t be correctly repaired because of the size or location of the injury. LIGHT TRUCK SERVICE MANUAL 3E-2 WHEELS AND TIRES METRIC TIRES Metric tires are available in two load ranges, Standard load and Extra load. Figure 3E-1 shows the meaning of the metric tire format. Most metric tire sizes do not have exact corresponding alpha tire sizes. For example, a P205/75R15 is not exactly equal in size and load carrying capacity to an FR78-15. For this reason, replacement tires should be of the same size, load range, and construction as those originally on the car. If metric tires must be replaced with other sizes, such as in the case of snow tires, a tire dealer should be consulted. Tire companies can best recommend the closest match of alpha to metric sizes within their own tire lines. METRIC TIRE SIZES P 205 / TIRE TYPE X P - PASSENGER T - TEMPORARY C - COMMERCIAL _ ........... ASPECT RATIO RIM DIAMETER (INCHES) [SECTION HEIGHT) 13 (SECTION WIDTH) 14 70 15 SECTION WIDTH 75 (MILLIMETERS) CONSTRUCTION TYPE 80 185 R - RADIAL 195 B - BIAS - BELTED 205 D - DIAGONAL (BIAS) ETC. The metric term for tire inflation pressure is the Kilopascal (kPa). Tire pressure will usually be printed in both kPa and psi. Metric tire gages are available from tool suppliers. The chart (Fig. 3E-2) converts commonly-used inflation pressures from kPa to psi. Fig. 3E-1--Metric Tire Size Format IN FLATIO N P R E S S U R E C O N V ER S ION CHART ( K IL O P A S C A L S TO P S I) psi kPa psi kPa 140 20 21 215 220 31 32 22 230 23 24 235 240 33 34 25 26 250 275 36 40 185 190 27 310 45 28 345 50 200 29 380 55 205 30 415 60 145 155 160 165 170 180 C onve rsion: 35 6.9 kPa = 1 psi Fig. 3E-2--lnflation Pressure Conversion REPLACEMENT WHEELS Wheels must be replaced if they become damaged (for example: bent, heavily rusted, leak air) or if wheel nuts often LIG H T T R U C K SERVIC E M A N U A L become loose. Do not use bent wheels which have been straightened, and do not use inner tubes in leaking wheels which are designed for tubeless tires. Such wheels may have structural damage and could fail without warning. The wheels originally equipped on the vehicle will provide optimum life up to the maximum load and inflation pressures shown in the Wheel Code and Limits Chart. M axim um loads, m axim um inflation pressures, wheel identification codes, and wheel sizes are stamped on each wheel. Service tested and approved wheels are available from service. When obtaining wheels for any reason from any other source, the replacement wheels should be equal in load capacity, inflation pressure capacity, diameter, width, offset and mounting configurations to those originally installed on the vehicle. A wheel of the wrong size or type may adversely affect load carrying capacity, wheel and bearing life, brake cooling, speedometer/odometer calibration, stopping abil­ ity, headlight aim, bumper height, vehicle ground clearance, and tire clearance to the body and chassis. Replacement with "used" wheels is not advised: they may have been subjected to harsh treatm ent or very high mileage and could fail without warning. The use of wheels a n d /o r tires with higher load carrying limits than originally equipped on the vehicle does not in itself increase the G A W R or the G V W R of the vehicle. WHEELS AND TIRES r. □ L B /'k i) MFD. BY GENERAL MOTORS CORP 0 8 /7 8 GVW R Cj A W R F R T 4 0 0 0 /1 8 1 4 1 4 0 0 0 /6 3 5 0 T IR E S R IM S P S l/k P . 3E-3 10 16 C O LD DUAL 5X16 5D 5 X 9 /5 3 6 /2 4 8 G AW R RR 10000 4 5 36 10 5 X16 16 6 X 9 4 2 290 51 75 U U tH A l MIMUH U HiC i f SAM Tv l HIS VI MU. | | C !)\ I IIRMS 10 A| I f ON TH > E DATE M ANUF AC TU R E SHO W N A B O V E I c G Q I 691100001 B U S - N O T S C H O O L BU S SE E O W NERS M A N U AL F OH A D D IT IO N A L IN FO R M A TIO N E XAMPL E ONLY Fig. 3E-3~Certification Label FRONT FRONT FRONT FRONT 4 WHEEL ROTATION 5 WHEEL ROTATION ¥ 4 WHEEL ROTATION 5 WHEEL ROTATION • PREFERRED FOR RADIAL TIRES • OPTIONAL FOR RADIAL TIRES * • MANDATORY FOR BIAS TIRES * THE OPTIONAL ‘X ’ ROTATION PATTERN FOR RADIALS IS ACCEPTABLE WHEN REQUIRED FOR MORE UNIFORM TIRE WEAR. Fig. 3E-5--Tire Rotation SERVICE OPERATIONS CAUTION:Servicing of tires mounted on multi­ piece rims requires proper tools, safety equipment and specialized training. Severe injuries can result from improper servicing techniques. It is recom­ mended that tires on multi-piece rims be serviced only by competent personnel with proper equip­ ment or by competent truck tire repair shops. TIRE INSPECTION AND ROTATION (Figs. 3E-4, 3E-5) Front and rear tires perform different jobs and can wear differently depending on the type of roads driven, individual driving habits, etc. To obtain maximum tire life, tires should be inspected at intervals shown in Section OB. For the longest tire life, any time irregular wear is noticed, the tires should be inspected and rotated and the cause of the uneven wear corrected. Be certain to check wheel nut tightness and to adjust the tire pressures, front and rear, after rotation to agree with those recommended in the tire inflation charts. The outer tire on a dual wheel will skid or drag on a turn because of the difference in the turning radii of the inner and outer tires. This results in faster wear of the outer tire. In general, the tire with the largest diameter or least wear whould be at the outside of each dual wheel. In addition, when trucks are operated continuously on high crown roads an increase in air pressure of from 5 to 10 PSI in the outside tire of each dual produces maximum tire life. As shown in Fig. 3E-5, the X method of rotation is allowed with radial tires if necessary. Due to their design, radial tires tend to wear faster in the shoulder area LIG H T TR U C K SE RV IC E M A N U A L 3E-4 WHEELS AND TIRES particularly in the front positions. This makes regular rotation especially necessary. Too low an air pressure can result in tire overloading, abnormal tire wear, adverse vehicle handling, and reduced fuel economy. The tire flexes more and can build up excessive heat, weakening the tire and increasing suscepti­ bility to damage or failure. Too high an air pressure can result in abnormal wear, harsh vehicle ride, and increased susceptibility to damage from road hazards. Lower inflation pressures should be used only with reduced vehicle loads and the rear tire pressure should be equal to or greater than the front pressure on single wheel application. After determin­ ing the load on each tire by weighing the vehicle on a scale, the correct cold inflation pressures for the actual tire loads can be obtained from the Tire/W heel Load and Inflation Pressure Charts shown in this section. Refer to Section OB for additional information on inflation pressure. INFLATION PRESSURE The maximum cold inflation pressures for the factory installed tires are listed on the Certification Label. Tires must be inflated to these pressures when the G V W R or an axle G A W R is reached. Improper tire inflation pressures for the load the vehicle is carrying can adversely affect tire life and vehicle performance. For improved ride comfort in vehicles rated at 8600 G V W R , it is permissible to use the lower tire pressure valves shown on the label located on the rear edge of the driver’s door provided there is a m aximum of 200 lbs. cargo, no slide in camper, and there are three or less occupants. The lower G V W R and G A W R (rear) reflect the m axim um load carrying capacity of the tires at lower pressure. W H E E L USAGE A N D T IR E L O A D L IM IT S (LBS) A T V A R IO U S I N F L A T IO N PRESSURES BIA S L IG H T T R U C K (L T ) T IR E S Wheel Code Tire Size Load Range 30 | 35 40 | Inflation Pressures (PSI) 45 | 50 | 55 | 60 | 65 | 70 1 75 T IR E S U SED AS S IN G L E S YF YF 9.50-16.5 9.50-16.5 ZX ZX ZX 7.00-16 7.50-16 7.50-16 C C D 1260 1430 1430 1365 1565 1565 1475 1690 1690 1580 1815 1815 1930 2040 2140 YD YD 8.75-16.5 8.75-16.5 C D 1380 1380 1515 1515 1630 1630 1750 1750 1855 1970 2070 D E 1860 1860 2030 2030 2190 2190 2350 2350 2500 2500 2650 2650 2780 2780 2920 3050 3170 T IR E S U SED AS D U A L S WHEEL CODE AND LIMITS Code CF, BU BT, CK Size of Wheel 15 x 7 JJ 15 x 8 JJ XH 15 x 6 JJ 16.5 x 6.00 YD CC 15 x 6 JJ ZY 19.5 x 6.00 BW, ZC 15 x 8 JJ W heel Limits Max. Max. Load Press. (Lb*.) (PSI) 1670 1910 1670 2680 1670 2540 2030 40 40 55 85 55 80 46 Code YC YF BF XW ZT ZX YD Size of Wheel 16.5 x 6.00 16.5 x 6.75 16 x 6 V2 L 15 x 6 JJ 19.5 x 6.00 16 x 6 KS 16.5 x 6.00 Wheel Limits Max. Max. Load Press. (Lbs.) (PSI) 2350 3170 2780 1910 2780 2440 2680 70 85 85 70 95 75 55 Optional Location Location For: • Maximum Load • Maximum Pressure • Wheel Code • Wheel Size Stamps Fig. 3E-6--Tire/W heel Load and Inflation Pressure L IG H T T R U C K SERVICE M A N U A L WHEELS AND TIRES W HEEL USAGE A N D T IR E L O A D L IM IT S (LBS) A T V A R IO U S I N F L A T I O N PRESSURES B IA S L IG H T T R U C K (L T ) T IR E S Tire Size Wheel Code YF Load Range 30 35 40 D E 1860 1860 2030 2030 2190 2190 9.50-16.5 9.50-16.5 YF Inflation Pressures (PSI) 60 45 55 50 2350 2350 2500 2500 2650 2650 65 70 75 2920 3050 3170 2780 2780 WHEEL CODE AND LIMITS Code Size of Wheel CH ZW. YD CC ZV BW. ZC 15 x 8 JJ 16.5 x 6.00 15 x 6 JJ 19.5x6.00 15 x 8 JJ Wheel Limits Max. Max. Press. Load (PSI) (Lba.) 40 1760 85 2680 55 1670 80 2540 40 2030 Wheel Limits Max. Max. Press. Load (PSI) (Lbs.) Code Size of Wheel YC YC BF XX ZT zx 16.5 x 6.00 16.5 x 6.75 16 x 6 V2 L 15 x 6 JJ 19.5x6.00 16 x 6 KS 2350 3170 2780 2040 2780 2440 70 85 85 70 95 75 • Wheel Code • Wheel Size Stamps Fig. 3E-7--Tire/Wheel Load and Inflation Pressure-K Models WHEEL USAGE AND TIRE LOAD LIM ITS AT VARIOUS INFLATION PRESSURES* BIAS TIRES FOR LIG H T TRUCKS USED AS SINGLES Wheel Code Regular O p tio n a l YJ YJ _ Tire Size 8.75-16.5 8.75-16.5 — Load Range Ply Rating 30 35 Tire Load Limits at Various Inflation Pressures (PSI) 40 45 50 55 60 D E 8 10 1570 1570 1720 1720 1850 1850 1990 1990 2110 2110 2240 2240 2350 1620 1710 1800 2350 WIDE BASE TUBELESS TIRES USED AS DUALS YD YD YH YH 8.00-16.5 8.00-16.5 6 8 C D 1195 1195 1310 1310 1415 1415 1520 1520 Wheel load limits are shown below. Vehicle loading must be limited such that neither the wheel or tire load limits are exceeded. W H E E L C O D E A N D L IM IT S Code YH YD, YH YJ CD XW BX A LU M . Size of Wheel Wheel Limits Max. Press. Max. Load (PSI) (Lbs.) 15 x 6 JJ 16.5 x 6.00 16.5 x 6.75 15 x 6V2 JJ 15 x 6 Jj 15 x 7 JJ 1585 40 2680 2680 1690 1916 85 85 1690 40 15 x 6 'A JJ 1690 40 40 70 • Wheel Code Fig. 3E-8--Tire/Wheel Load and Inflation Pressure-G Models LIG H T T R U C K SERVICE M A N U A L 65 70 75 2470 2570 2680 3E-5 3E-6 WHEELS AND TIRES MINIMUM TIRE INFLATION PRESSURE AT GROSS VEHICLE WEIGHT RATING GVWR LBS. W H E EL CODE AN D L IM IT S W HE EL L IM IT S S IZ E OF W HEEL CODE STAMPING LOCATION I FOR RIM SIZE M A X. PRESS. (P S I) 85 1 6 .5 x 6 .0 2680 YC 1 6 .5 x 6 .0 2350 70 YF 1 6 .5 x 6 .7 5 3170 85 BF 16 x 6 .5 0 L 2780 85 ZX 16 x 6 .0 0 KS 2440 75 Y D , YJ OPTIONAL LOCATION DUAL WHEELS M AX. LOAD (L B S .) LOCATION FOR: / MAXIMUM^MAXIMUM / WHEEL LOAD / PRESSURE/ CODE STAMPS /; WHEEL USAGE AND TIRE LOAD LIMITS (LBS) AT VA RIO U S INFLATION PRESSURES PASSENGER TYPE TIRES FOR LIGHT TRUCKS Wheel Code Tire Size Load Range XW xw L78-15 L78-15 B Inflation Pressure (PSI) 24 1527 1527 D 26 1590 1590 32 1790 1790 30 1727 1727 28 1663 1663 34 36 38 40 1854 1905 1972 2025 TIRES USED AS SINGLES BIAS LIGH T TRUCK (LT) TYPE TIRES Inflation Pressures (PSI) W heel Code T ire Size Range 30 BF BF BF 7 .5 0 -1 6 L T 7 .5 0 -1 6 L T 7 .5 0 -1 6 L T C D E YC YC YF YF YF 8 .7 5 - 1 6 .5 8 .7 5 - 1 6 .5 8 .7 5 - 1 6 .5 9 .5 0 - 1 6 .5 9 .5 0 - 1 6 .5 C D E 0 E Load 35 40 45 SO 55 60 65 70 75 1620 1620 1620 1770 1770 1770 1930 1930 1930 2060 2060 2060 2190 2190 2310 2310 2440 2440 2560 2670 2780 1570 1570 1570 1860 1860 1720 1720 1720 2030 2030 1 85 0 1850 1850 2190 2190 1990 1990 1990 2350 2350 2110 2110 2500 2500 2240 2240 2650 2650 2350 2350 2780 2780 2470 2570 2680 2920 3050 3170 BIAS TRUCK TYPE TIRES W h eel Code T ire Size R egular ZY & ZT Load Range 8 -1 9 .5 — D -E In fla tio n Pressures (P S I) 30 35 40 45 50 55 60 65 70 75 - — - - 2110 2270 2410 2540 2680 2800 70 75 TIRES USED AS DUALS BIAS LIG H T TRUCK (LT) TYPE TIRES W heel Code ZX ZX Inflation Pressures (PSI) T ire Size Load Range 30 35 40 45 7 .5 0 -1 6 L T 7 .5 0 -1 6 L T 8 .7 5 - 1 6 .5 8 .7 5 - 1 6 .5 C D C D 1430 1430 1380 1380 1565 156 5 1 51 5 1515 1690 1690 1630 1630 1815 18 1 5 1750 1750 8 -1 9 .5 8 -1 9 .5 D E — — — — 50 55 60 1930 2040 2140 185 5 1970 2070 2230 2230 2350 2350 65 | BIAS TRUCK TYPE TIRES ZY , ZT ZY 1850 1850 1990 1990 2110 2110 2460 2460 2570 2 6 8 0 (#; (#) 2 7 8 0 lb s . a t 8 0 lb s . p re s s u re . Fig. 3E-9--Tire/Wheel Load and Inflation Pressure-P Models LIG H T T R U C K SE RV IC E M A N U A L WHEELS AND TIRES CORRECTING IRREGULAR TIRE WEAR Heel and Toe Wear This is a saw-toothed effect where one end of each tread block is worn more than the other. The end that wears is the one that first grips the road when the brakes are applied. Heel and toe wear is less noticeable on rear tires than on front tires, because the propelling action of the rear wheels creates a force which tends to wear the opposite end of the tread blocks. The two forces, propelling and braking, make for more even wear of the rear tires, whereas only the braking forces act on the front wheels, and the saw-tooth effect is more noticeable. A certain amount of heel and toe wear is normal. Excessive wear is usually due to high speed driving and excessive use of brakes. The best remedy, in addition to cautioning the owner on his driving habits, is to interchange tires regularly. Side Wear This may be caused by incorrect wheel camber, un­ derinflation, high cambered roads or by taking corners at too high a rate of speed. The first two causes are the most common. Camber wear can be radily identified because it occurs only on one side of the treads, whereas underinflation causes wear on both sides. Cam ber wear requires correction of the camber first and then interchanging tires. There is, of course, no correction for high cambered roads. Cornering wear is discussed further on. 3E-7 resulting in excessive wear on the outside half of the tire, producing a type of wear like that caused by excessive positive camber. Cornering wear can be most easily distinguished from abnorm al cam ber wear by the rounding of the outside shoulder or edge of the tire and by the roughening of the tread surface which denotes abrasion. Cornering wear often produces a fin or raised portion along the inside edge of each row in the tread pattern. In some cases this fin is almost as pronounced as a toe-in fin, and in others, it tapers into a row of tread blocks to such an extent that the tire has a definite "step wear" appearance. The only remedy for cornering wear is proper instruc­ tion of operators. Driving more slowly on curves and turns will avoid grinding rub ber off tires. To offset normal cornering wear as much as possible tires should be inter­ changed at regular intervals. Wheel and Tire Balancing It is desirable from the standpoints of tire wear and vehicle ride and handling ease to maintain proper balance of wheel and tire assemblies on all models. This m ay be accomplished by either of the two types of balancing systems in currect use which balance wheels either on the vehicle or off. The "on the vehicle" type, however, is the more desirable in that all rolling components (brake drums, bearings, seals, etc.) are included in the balancing procedure and thereby have any existing unbalance corrected. Misalignment Wear Truck Wheel Balance Weights This is wear due to excessive toe-in or toe-out. In either case, tires will revolve with a side motion and scrape the tread rubber off. If misalignment is severe, the rubber will be scraped off of both tires; if slight, only one will be affected. The scraping action against the face of the tire causes a small feather edge of rubber to appear on one side of the tread and this feather edge is certain indication of misalignment. The remedy is readjusting toe-in, or recheck­ ing the entire front end alignment if necessary. All truck wheels equipped with a tubular side ring (rolled flange rim) on the outboard side of the wheel rims require special design weights to fit. Dynamic balancing can be accomplished through use of these special balance weights which are designed only for installations on the outboard side of these wheels. Conventional weights fit only the inboard side of these wheels. Uneven Wear Static balance (sometimes called still balance) is the equal distribution of weight of the wheel and tire assembly about the axis of rotation in such a m an ner th a t the assembly has no tendency to rotate by itself, regardless of its position. For example: A wheel with chunk of dirt on the rim will always rotate by itself until the heavy side is a the bottom. Any wheel with a heavy side like this is statically out of balance. Static unbalance of a wheel causes a hopping or pounding action (up and down) which frequently leads to wheel "flutter" and quite often to wheel "tra m p " . Uneven or spotty wear is due to such irregularities as unequal caster or camber, bent front suspension parts, outof-balance wheels, brake drums out of round, brakes out of adjustment or other mechanical conditions. The remedy in each case consists of locating the mechanical defect and correcting it. Cornering Wear When a truck makes an extremely fast turn, the weight is shifted from an even loading on all wheels to an abnormal load on the tires on the outside of the curve and a very light load on the inside tires, due to centrifugal force. This unequal loading may have two unfavorable results. First, the rear tire on the inside of the curve may be relieved of so much load that it is no longer geared to the road and it slips, grinding off the tread on the inside half of the tire at an excessive rate. This type of tire shows much the same appearance of tread wear as tire wear caused by negative camber. Second, the transfer of weight may also overload the outside tires so much th a t they are laterally distorted LIGHT TRUCK SERVICE MANUAL Static Balance Dynamic Balance Dynamic balance (sometimes called running balance means that the wheel must be in static balance, and also run smoothly at all speeds. To insure successful, accurate balancing, the following precautions must be observed: • Wheel and tire must be clean and free from all foreign matter. • The tires should be in good condition and properly mounted with the balance mark on the tire, if any, lined up with the valve. 3E-8 WHEELS AND TIRES • Bent wheels that have runout over 1/16" should be replaced. • Inspect tire and wheel assembly to determine if an eccentric or out-of-round condition exists. Note that this condition, if severe, cannot be "balanced ou t". An assembly which has an out-of-round condition exceed­ ing 3/16 " on tire sizes through 19.5" is not suitable for use on the front of the vehicle. Its use on the rear should be governed by its general condition and whether the roundness defect seriously detracts from overall ride quality. • When balancing wheels and tires, it is recommended that the instructions covering the operation of the wheel balancer being used be closely followed. • When balancing truck type nylon tires, tires must be hot (run for several miles) before raising vehicle to balance so that flat spot is elimated. A tire which is flat spotted will be incorrectly balanced. • On 10 and 20 series trucks, do not attem pt to externally drive the wheels with the transfer case in the neutral position. Although, the transfer case will be uncoupled from the transmission, the front and rear drive trains will be coupled through the transfer case. For example, attempting to balance a rear wheel on the vehicle will cause one or both of the front wheels to also be driven. T he wheels may be dynam ically balanced on the vehicle with the transfer case in the 2H position. The transfer case neutral position should only be used when it becomes necessary to uncouple the transmission from the transfer case. WHEEL INSTALLATION Single Wheels When installing the tire and wheel on the vehicle, the following procedure should be followed: After wheel nuts are put on loosely, turn the wheel until one nut is at the top of the bolt circle; tighten the nut just snug. Snug up the remaining nuts criss-cross to minimize runout, then tighten the nuts to the recommended torque alternately and evenly to avoid excessive runout. CAUTION:Before re-installing wheels, remove any build up of corrosion of the wheel mounting surface and brake drum or disc mounting surface by scraping and wire brushing. Installing wheels without good metal-to-metal contact at the mounting surfaces can cause wheel nuts to loosen which can later allow a wheel to come off while the vehicle is moving, possibly causing loss of control. Dual Wheels W hen installing wheels on vehicles with dual rear wheels: 1. Install inner and outer wheel and clamp ring on rear, or wheel and clamp ring on front (be sure pins on clamp ring face outboard). 2. Install and snug nuts finger tight. 3. Torque nuts to specified torque in sequence shown in Fig. 3E-12. Lateral runout should not exceed 1/8" on front wheel or 3 /1 6" on rear wheel. Attachment of Dual Wheels On P300 Models To assure secure attachm ent of the dual disc wheels, it is important that all dirt or rust scale be removed from the mating surface of the wheels, hub, and clamp ring as well as the stud and nut. P O W E R D R IV E N U T S T H E N M A N U ­ A L L Y IN S P E C T T O R Q U E A T 130-180 FT. LBS. M A N ­ U A L T O R Q U E O N L Y : 150-200 FT. LB. Side and Lock Rings Side and lock rings of different rim types are not interchangeable. Some may appear to be, but they do not fit peoperly on the rim base. Serious accidents have resulted from the use of mismatched rings. Rim base and rings must be matched according to manufacturer, size and type. This information is stamped on each part. Inspection for Leaks 1. With wheel assembly removed from vehicle, inflate the tire to recommended operating pressure. 2. Check for leaks at rim bead by placing wheel and tire horizontal and allowing w ater to stand in groove between rim and tire. Check for other leaks by lowering assembly into water tank or running water over tire. Installing Synthetic Tubes NOTICE: When tube and flap are not properly lubri­ cated and mounted, they will stretch thin in the tire bead and rim region. This will cause prem ature failure. 1. Before installing tube in tire, clean inside of casing thoroughly. 2. Insert tube in tire and inflate until it is nearly rounded out. 3. Inspect rim for rust scale and bent flanges-clean rust scale and straighten flanges where necessary. 4. Using a brush or cloth swab, apply a solution of neutral vegetable oil soap to the inside and outside of tire beads and also the the rim side of the tube. Do not allow soap solution to run down into tire. 5. When mounting tire and tube on a drop center rim, follow the standard procedure. Be sure tire is centered on rim so that beads are out of rim well before inflating. Do not allow tire to hang loosely on wheel while inflating. LIGHT TRUCK SERVICE MANUAL WHEELS AND TIRES 6. Center valve and pull it firmly against the rim. Hold in this position and inflate until tire beads are firmly seated on rim against flanges. 7. Completely deflate tire by removing valve core. 8. Reinflate tire to recommended pressure. TUBELESS TIRES Tubeless tires mounted on one piece full drop center rims are standard on some trucks. These tires have a safety inner liner which if punctured, tends to cling to the penetrating object forming a partial seal until the object is removed from the tire. Mounting and Demounting Use a tire changing machine to mount or demount tires. Follow the equipment m anufacturer’s instructions. Do not use hand tools or tire irons alone to change tire as they may damage the tire beads or wheel rim. Rim bead seats should be cleaned with a wire brush or coarse steel wool to remove lubricants, old rubber, and light rust. Before mounting or demounting a tire, the bead area should be well lubricated with an approved tire lubricant. After mounting, inflate to 40 psi so that beads are completely seated. CAUTION:Do not stand over tire when inflating. Bead may break when beads snaps over safety hump and cause serious personal injury. Do not exceed 275 kPa (40 psi) pressure when inflating. If 275 kPa (40 psi) pressure will not seat beads, deflate, re-lubricate and reinflate. Overin­ flation may cause the bead to break and cause serious personal injury. Install valve core and inflate to proper pressure. Check the locating rings of the tire to be sure they show around the rim flanges on both sides (Fig. 3 E - 14). 3E-9 RADIAL TIRES Recommended truck tire mounting and inflation proce­ dures are especially im p ortant with radial truck tires. Failure to follow these recommendations can cause bead deformation in both tube type and tubeless tires due to incorrect bead seating. Bead deformation may lead to chafing, lower sidewall and bead area cracking, demounting difficulties, eccentric wear, ride vibration and non-retreadable casing. Mounting To insure correct mounting and bead seating and to prevent bead deform ation, the following steps must be taken: A. Tube Type Tires 1. Only use rims approved for radial tire usage by rim manufacturer. Thoroughly clean rim parts, removing all rust and other foreign material. Make sure rim parts match and are not sprung or broken. 2. Thoroughly lubricate tire beads, portion of tube between beads, and flaps with an approved rubber lubricant. Radial tubes are identifiable by the letter " R " in the size designation. Example 100R20. Also, to further identify the radial tube, a red band on the valve stem has been required since March, 1975. Radial flaps are also identified by the letter " R " . Example - 20R8. NOTICE: Do not use silicone base lubricants - this could cause the tire to slip on the wheel. 3. Double inflate. Inflate to operating pressure, deflate completely and reinflate to operating pressure. This allows tube, flap and tire to fit together properly. 4. Check bead seating. Visually check slot and side ring gap (on two piece rim) to make sure bead is seated. The flange and one of the three lower sidewall rim line rings while the tire is laying flat (measurements should be taken each 90° around the circumference of the rim flange). If spacing is uneven around bead from side to side, repeat Step 1 through 3, and recheck. B. Tubeless Tires. 1. Only use rims approved for radial tire usage by rim manufacturer. Thoroughly clean rim, removing all rust and other foreign material. 2. Thoroughly lubricate tire beads and rim bead seats with an approved rubber lubricant. NOTICE: Do not use silicone base lubricants - this could cause the tire to slip on the wheel. 3. Inflation. Inflate tire to operating pressure. Due to the construction of radial truck tires, particularly in the lower sidewall and bead area, it may be difficult to get the tire to take air. An inflation aid may be necessary to help seat the bead of tubeless radial tires. Two types of inflation aids are commercially available, (1) metal rings which use compressed air to seat beads, and (2) rub ber rings which seal between the tirebead and rim bead seat allowing the bead to move out and seat. Lubrication is mandatory with both items. 4. Check bead seating. This check is made by measur­ ing the space between the rim flange and one of the L IG H T T R U C K SERVICE M A N U A L 3E-10 WHEELS AND TIRES three lower sidewall rim line rings while the tire is laying flat (measurements should be taken each 90° around the circum ference of the rim flange. If spacing is uneven around the bead from side to side, repeat Steps 1 through 3, and recheck. It’s important that this procedure be followed to insure proper bead seating in order to prevent bead deformation. Radial tires, as well as the bias tires, must be mounted and inflated in accordance with safety precautions noted in RM A Radial and Bias Truck Tire Service Manuals. TIRE REPAIR There are many different materials and techniques on the market to repair tires. As not all of these work on all types of tires, tire manufacturers have published detailed instructions on how and when to repair tires. These instruc­ tions can be obtained from the tire manufacturer. Series Description K C 1 0 ,P 1 0 , G 1 0 ,G 2 0 C20,P20 C30, P30 and K20, G30 Torque 7 / 1 6 " B o lts (6) 1 / 2 " B o lts (5) 70-9 0 Ft. Lbs. 75-1 00 Ft. Lbs. 9 /1 6 " B o lts (8) 90-1 2 0 Ft. Lbs. 9 /1 6 " B o lts (8) 110-140 Ft. Lbs. Single Wheels CKPG30 D u al W heels H eavy D u ty W heels 5 /8 " B o lts 130-180 Ft. Lbs. (10) Fig. 3E-12--Wheel Nut Torque LIG H T T R U C K SE RV IC E M A N U A L PROPELLER SHAFT 4A-1 SECTION 4A PROPELLER SHAFT The following notice applies to one or more steps in the assembly procedure of components in this portion of the manual as indicated at appropriate locations by the terminology "See Notice on page 1 of this Section". N O T IC E : This fastener is an important attaching part in that it could affect the performance of vital components and systems, a nd/or could result in major repair expense. It must be replaced with one of the same part number or with an equivalent part if replacement becomes necessary. Do not use a replacement part of lesser quality or substitute design. Torque values must be used as specified during reassembly to assure proper retention of this part. CONTENTS General D escription...........................................................................................4A-1 Universal Jo in ts............................................................................................... .4A-1 Propeller S h a f t ................................................................................................ ..4A-2 Diagnosis.............................................................................................................. ..4A-2 On C ar Service....................................................................................................4A-5 GENERAL DESCRIPTION Universal Joints The simple universal joint is basically two Y-shaped yokes connected by a crossmember called a spider. The spider is shaped like an X and arms that extend from it are called trunnions. See figure 4 A - 1. The spider allows the two yoke shafts to operate at an angle to each other. When torque is transmitted at an angle, through this type of joint, the driving yoke rotates at a constant speed while the driven yoke speeds up and slows down twice per revolution. This changing of velocity (acceleration) of the driven yoke increases as the angle between the two yoke shafts increases. This is the prime reason why single universal joints are not used for angles greater than three to four degrees. At four degrees, for example the change of velocity is .5%. At ten degrees it is 3%. If the universal joint were set at 30 degrees and the driving yoke were turning at 1000 RPM the velocity of the driven yoke would change from 856 RPM to 1155 R PM in one q u a rte r of a revolution. In the rem aining q u a rte r revolution the velocity would change from 1155 R PM to 866 RPM . On a one-piece drive shaft this problem can be elimi­ nated by arranging two simple universal joints so that the two driving yokes are rotated 90 degrees to each other. However the angle between the drive and driven yokes must be very nearly the same on both joints for this to work. Refer to figure 4A-2. This allows the alternate acceleration and deceleration of one joint to be offset by the a lte rn a te deceleration and acceleration of the second joint. When the two joints do not run at approximately the same angle, operation can be rough and an objectionable vibration can be produced. Fig. 4A-2--U niversal Joints A rra n g e d for Constant Fig. 4A-1 --Simple Universal Joint Velocity LIG H T T R U C K SERVICE M AN U AL 4A-2 PROPELLER SHAFT Essentially, the constant velocity joint is two simple universal joints closely coupled by a coupling yoke, phased properly for constant velocity. A centering ball socket between the joints maintains the relative position of the two units. This centering device causes each of the two units to operate through one-half of the complete angle between the drive shaft and differential carrier. See figure 4A-3. The ball/socket on this Constant Velocity joint requires periodic lubrication. A lubrication fitting is provided for this purpose, and is illustrated later in this section. Propeller Shafts Universal joints are designed to consider the effects of various loadings and rear axle windup, during acceleration. Within the design angle variations the universal joints will operate safely and efficiently. However, when the design angles are exceeded the operational life of the joints may decrease. The bearings used in universal joints are the needle roller type. The needle rollers are held in place on the trunnion by round bearing cups. The bearing cups are held in the yoke by either (depending on the manufacturer) snap rings or plastic injection. These joints usually are lubricated for life and cannot be lubricated while on the vehicle. Constant Velocity Joint-Double Cardan Joint As mentioned previously, the simple universal joint will operate efficiently through small angles only. Also, two simple universal joints phased properly and operating through the same angle will transmit constant velocity. When a large angle is encountered in a driveline, a simple universal joint will introduce two vibrations in each revolu­ tion. It is in this situation that a constant velocity joint is used. The propeller shaft is a steel tube which is used to transmit power from the transmission output shaft to the differential. To accommodate various model, wheelbase and transmission combinations, drive shafts differ in length, diameter and the type of splined yoke. Each shaft is installed in the same manner. A universal joint and splined slip yoke are located at the transmission end of the shaft, where they are held in alignment by a bushing in the transmission rear extension. The slip yoke permits fore and aft movement of the drive shaft as the differential assembly moves up and down. The spline is lubricated internally by transmission lubricant or grease. An oil seal at the transmission prevents leakage and protects the slip yoke from dust, dirt and other harmful material. Since the drive shaft is a balanced unit, it should be kept completely free of undercoating and other foreign material which would upset shaft balance. Both one piece and two piece propeller shafts are used depending on the model. All are tubular and use needle bearing type universal joints. On models that use a two piece shaft, the shaft is supported near its splined end in a rubber cushioned ball bearing which is mounted in a bracket attached to a frame crossmember. The ball bearing is permanently lubricated and sealed. Four wheel drive models use a front propeller shaft incorporating a constant velocity joint. PROPELLER SHAFT AND Uh /ERSAL JOINT DIAGNOSIS Checking and Correcting Propeller Shaft Unbalance 1. Place vehicle on a twin post hoist so that the rear wheels are free to rotate. 2. Remove both rear tire and wheel assemblies and brake drums. Use care not to apply brakes with drums removed. 3. Visually inspect propshaft, U-Joints and attachments for mud undercoating or other discrepancies. Make necessary corrections prior to running. LIGHT TRUCK SERVICE MANUAL 4. With vehicle running in gear at the indicated speed where disturbance is at its peak, observe the intensity of the disturbance. 5. Stop engine and disconnect drive shaft from companion flange. Reinstall shaft by rotating it 180° from its original position. D eterm ine which position of the companion flange gives the best balance. 6. Install rear drums and wheels, and road test vehicle for final check of balance. If balance is still unacceptable, replace drive shaft. PROPELLER SHAFT 4A-3 D IA G N O STIC CH ART CO M PLAINT L eak a t fro n t slip y o k e . N O T E : An occasional d ro p o f lu b ric a n t leaking fro m splined y o k e is n o rm al and re q u ire s n o a tte n tio n . CO RRECTIO N POSSIBLE CAUSE a. R ou g h o u tsid e surface o n splined yoke. b. D efective tran sm issio n rear oil seal. a. R eplace seal if c u t by b u rrs on y o k e . M inor b u rrs can be s m o o th e d by carefu l use o f c ro cu s c lo th or h o n in g w ith a fine sto n e . R eplace y o k e if o u tsid e surface is ro ugh o r b u rre d b a d ly . b. R eplace transm ission re ar oil seal. c. Bring tran sm issio n oil u p to p ro p e r level a fte r c o rre c tio n . K n o ck in drive line, clu n k in g noise w hen car is o p e ra te d u n d e r flo atin g c o n d itio n at 10 m p h in high gear or n e u tra l. a. W orn o r dam aged universal jo in ts. a. D isassem ble universal jo in ts , in sp e ct an d replace w o rn or d am ag ed p a rts. b. Side gear h u b c o u n te rb o re in d iffe re n tia l w o rn oversize. b. R eplace d iffere n tia l case a n d /o r side gears as re q u ire d . Ping, S nap o r C lick in drive line. a. L oose u p p e r o r lo w e r c o n tro l arm b u sh in g b o lts. a. T ig h te n b o lts to specified to rq u e . N O T E : U sually o ccu rs o n initial lo ad a p p lic atio n a fte r tran sm issio n has b e en p u t in to gear, e ith e r fo rw a rd o r reverse. b. L oose c o m p a n io n flange. b. R em ove c o m p a n io n flange, tu rn 180° fro m its original p o sitio n , ap p ly w hite lead to splines and re in sta ll. T ig h te n p in io n n u t to specified to rq u e . Fig. 4 A -4 --D iag n o sis C hart A LIGHT TRUCK SERVICE MANUAL 4A-4 PROPELLER SHAFT C O M P L A IN T Roughness, Vibration or Body Boom at any speed. NOTE: With tachometer installed in car, determine whether propeller shaft is cause of complaint by driving through speed range and note the engine speed (rpm) at which vibration (roughness) is most pronounced. Then, shift transmission to a different gear range and drive car at same engine speed (rpm) at which vibration was noted before. Note the effect on the vibration. If vibration occurs at the same engine speed (rpm), regardless of transmission gear range selected, drive shaft assembly is not at fault, since the shaft speed (rpm) varies. If vibration decreased, or is eliminated, in a different gear range but at the same engine speed (rpm), check the possible causes: POSSIBLE CAUSE C O R R E C T IO N a. Bent or dented drive shaft. a. Replace. b. Undercoating on drive shaft. b. Clean drive shaft. c. Tire unbalance. (30-80 mph, not throttle conscious) c. Balance or replace as required. d. Excessive U-bolt torque. d. Check and correct to specified torque. e. Tight universal joints. e. Impact yokes with a hammer to free up. Overhaul joint if unable to free up or if joint feels rough when rotated by hand. f. Worn universal joints. f. Overhaul, replacing necessary parts. g. Burrs or gouges on companion flange. Check snap ring locating surfaces on flange yoke. g. Rework or replace companion flange. h. Drive shaft or companion flange unbalance. h. Check for missing balance weights on drive shaft. Remove and reassemble drive shaft to companion flange, 180° from original position. i. Excessive looseness at slip yoke spline. i. Replace necessary parts. j. j. Drive shaft runout (50-80 mph throttle conscious) Check drive shaft runout at front and rear. Should be less than specified. If above, rotate shaft 180° and recheck. If still above specified, replace shaft. Roughness usually at low speeds, light load, 15-35 mph. a. U-bolt clamp nuts excessively tight. a. Check and correct torque to that specified. If torque was excessive or if brenelled pattern on trunnions is evident, replace joints. Scraping noise. a. Slinger, companion flange, or end yoke rubbing on rear axle carrier. a. Straighten slinger to remove interference. Roughness on heavy acceleration (short duration.) a. Double cardan joint ball seats worn. Ball seat spring may be broken. a. Replace joint and shaft assembly. Roughness -- above 35 mph felt and/or heard. a. Tires unbalanced or worn. a. Balance or replace as required. Fig. 4A-5--Diagnosis Chart B LIGHT TRUCK SERVICE MANUAL PROPELLER SHAFT 4A-5 UNIT REPAIR PROPELLER SHAFT The rear universal joint to propshaft bolt on some CK 1 ton dual wheel models requires a # 10 "Six Lobed Socket" (J-25085), for proper removal and installation. 34 N-m, (Torque to 25 lbs. ft.). Removal 1. Raise vehicle on hoist. M ark relationship of shaft to companion flange and disconnect the rear universal joint by removing trummion bearing " U " bolts or straps. Tape bearing cups to trunnion to prevent dropping and loss of bearing rollers. 2. For models with two-piece shafts remove bolts retain­ ing bearing support to hanger. 3. Slide propeller shaft forward disengaging trunnion from axle flange, then slide assembly rearward disen­ gaging from transmission. For models using strap or U-bolt atta ch m e n ts to transmission or transfer case use same removal proce­ dure as above. Due to length of the propeller shaft it convenient to use a bench vise, for installation, instead of an arbor press. proceed with disassembly and assembly with an arbor press Fig. 4A-8 and 4A-9. may be more removal and In this case, procedure as 3. Using a suitable socket or rod, press on trunnion until bearing cup is almost out. Grasp cup in vise and work cup out of yoke. See figures 4A-8 and 4A-9. The bearing cup cannot be fully pressed out. 4. Press trunnion in opposite direction and remove other cup as in Step 3. 5. Clean and inspect dust seals, bearing rollers, and trunnion. Relubricate bearings as indicated in Section 0. Universal Joints On models with between center slip propshaft it is important that components are marked prior to dissassembly for proper phasing. The universal joints are of the extended-life design and do not require periodic inspection or lubrication; however, when these joints are disassembled, repack bearings and lubricate reservoir at end of trunnions with high-melting point wheel bearing lubricant. Use care not to damage or dislodge seals from trunnion. Snap Ring Type Disassembly 1. Remove bearing lock rings from trunnion yoke. 2. Support trunnion yoke on a piece of 31.75 mm (1 -1 /4 ") I.D. pipe on an arbor bed. Fig. 4A-8~Bearing Cup Removal with Vise LIGHT TRUCK SERVICE MANUAL 4A-6 PROPELLER SHAFT J-9522-3, on the open horizontal bearing cups, and press the lower bearing cup out of the yoke ear as shown in figure 4 A - 11. This will shear the plastic retaining the lower bearing cup. 2. If the bearing cup is not completely removed, lift the cross and insert Spacer J-9522-5 between the seal and bearing cup being removed, as shown in figure 4A-12. Complete the removal of the bearing cup, by pressing it out of the yoke. 3. R otate the drive shaft, shear the opposite plastic retainer, and press the opposite bearing cup out of the yoke as before, using Spacer J-9522. Fig. 4A -9--Bearin g C u p Rem oval with Press In addition to packing the bearings, make sure that the lubricant reservoir at the end of each trunnion is completely filled with lubricant. In filling these reser­ voirs, pack lubricant into the hole so as to fill from the bottom (use of squeeze bottle is recommended). This will prevent air pockets and ensure an adequate supply of lubricant. 4. Disengage cross from yoke and remove. Production universal joints cannot be reassembled. There are no bearing retainer grooves in production bearing cups. Discard all universal joint parts removed. 5. Remove the remains of the sheared plastic bearing retainer from the ears of the yoke. This will aid in reassembly of the service joint bearing cups. It usually is easier to remove plastic if a small pin or punch is first driven through the injection holes. Reassembly Fig. 4 A -1 0 1. Position trunnion into yoke. Paritally install one bearing cup into yoke. Start trunnion into bearing cup. Partially install other cup. Align trunnion into cup, and press cups into yoke. 2. Install lock rings. Injected Plastic Type Disassembly NOTICE: Never clamp drive shaft tubing in a vise as the tube may be dented. Always clamp on one of the yokes, and support the shaft horizontally. Avoid damaging the slip yoke sealing surface. Nicks may dam age the bushing or cut the seal lip. 1. Support the drive shaft in a horizontal position in ine with the base plate of a press. Place the universal joint so that the lower ear of the shaft yoke is supported on a 28.57 mm ( 1 - 1 / 8 " ) socket. Place the cross press, Fig. 4 A - 1 1--Pressing O u t Bearing C u p Fig. 4A-12--Using Spacer to Remove Bearing Cup LIGHT TRUCK SERVICE MANUAL PROPELLER SHAFT 6. If the front universal joint is being serviced, remove the pair of bearing cups from the slip yoke in the same manner. Reassem bly A universal joint service kit is used when reassembling this joint. See figure 4 A - 13. This kit includes one pregreased cross assembly, four service bearing cup assemblies with seals, needle rollers, washers, grease and four bearing retainers. Make sure that the seals are in place on the service bearing cups to hold the needle rollers in place for handling. 1. Remove all of the remains of the sheared plastic bearing retainers from the grooves in the yokes. The sheared plastic may prevent the bearing cups from being pressed into place, and this prevent the bearing retainers from being properly seated. 2 . Install one bearing cup part way into one side of the yoke, and turn this yoke ear to the bottom. 4A-7 4. Install opposite bearing cup part way. Make sure that both trunnions are started straight and true into both bearing cups. 5. Press against opposite bearing cups, working the cross all of the time to check for free movement of the trunnions in the bearings. If there seems to be a hang­ up, stop pressing and recheck needle rollers, to deter­ mine if one or more of them has been tipped under the end of the trunnion. 6. As soon as one bearing retainer groove clears the inside of the yoke, stop pressing and snap the bearing retainer into place as shown in figure 4A-15. 7. Continue to press until the opposite bearing retainer can be snapped into place. If difficulty is encountered, strike the yoke firmly with a hammer to aid in seating bearing retainers. This springs the yoke ears slightly. See figure 4A-16. 8. Assemble the other half of the universal joint in the same manner. 3. Insert cross into yoke so that the trunnion seats freely into bearing cup as shown in figure 4 A - 14. ROLLER BEARINGS BEARING RETAINER BEARING CUP CROSS ROUND PLASTIC WASHER Fig. 4A -15—Installing Snap Ring to Retain Trunnion Fig. 4 A -1 3 -R e p a ir Kit STRIKE TUBE YOKE EAR IN THIS AREA Fig. 4A-14-lnstalling Trunnion into Yoke Fig. 4A-16--Seating Snap Rings LIG H T T R U C K SERVICE M A N U A L 4A-8 PROPELLER SHAFT 9. Check the freedom of rotation of both sets of trunnions of the cross. If too tight, again rap the yoke ears as described above. This will loosen the bearings and help seat the bearing retainers. CENTER SUPPORT BEARING-FIG. 4A-17 length of pipe over splined end of shaft, press bearing and inner slinger against shoulder on shaft. d. Install dust shield over shaft, small diameter (Dana Style). Install bearing retainer (GM Style). e. Install rubber cushion onto bearing. f. Install bracket onto cushion. NO TICE: See N O T I C E on page 1 of this section regarding Center Support Bearing fasteners. 1. Remove strap retaining rubber cushion from bearing support. 2. Pull support bracket from rubber cushion and pull cushion from bearing. 3. Pull bearing assembly from shaft. 4. Assemble bearing support as follows: a. Install inner deflector on propeller shaft, if removed, and prick punch deflector at two opposite points to make sure it is tight on shaft (Dana Style). b. Fill space between inner dust shield and bearing with lithium soap grease (Dana Style). c. Start bearing and slinger assembly straight on shaft journal. Support propeller shaft and, using suitable g. Install retaining strap. Installation of Propshafts When reinstalling propshafts, it is necessary to place the shafts into particular positions to assure proper operation. This is called phasing. NOTICE: AH models with 32 splines use an alignment key, as shown in figure 4A-18, to obtain proper phasing. The shafts can mate only in the correct position. G and K models with 16 splines must be phased as shown in figure 4A-19. 1. For models with one piece propeller shafts, slide shaft into transmission and attach rear U-joint to axle. Fig. 4A-17--Propeller Shaft, Universal Joint and Bearing Support LIG H T T R U C K SERVICE M A N U A L PROPELLER SHAFT 4A-9 3. For G-K models with two piece shafts, install front half into transmission and bolt support to crossmember. a. Slide grease cap and gasket onto rear splines. b. Rotate shaft so front U-joint trunnion is in correct position. See figure 4 A - 19. c. Take rear propeller shaft and before installing, align U-joint trunnions as shown in figure 4A-19. Attach rear U-joint to axle. Tighten grease cap. d. Torque bearing support to crossmember and U-joint to axle attachments. CONSTANT VELOCITY UNIVERSAL JOINT Inspection Fig. 4A-18--Alignment Key On vehicles w ith tw o piece p ro p sh a fts, the fr o n t p ro p sh a ft yo ke m u st be bottom ed out in the transm is­ sion f u l l y fo rw a rd before installation to the hanger. 2. For C-P models with two-piece propeller shafts, proper phasing is accomplished with the alignment key, shown in figure 4A-18. An inspection kit including two bearing caps and two snap rings is available to allow the removal of the two trunnion caps shown at location 1, in figure 4A-20. Mark the flange yoke and coupling yoke for reassembly in the same position, as shown in figure 4A-21. To service the trunnion caps, use the appropriate procedures given in the beginning of this Section. When both bearing cups are free, disengage the flange yoke and trunnion from the centering ball. Note that the ball 2-Piece prop shaft must be assembled as follows to prevent excessive drive line excitation: 1. Transmission yoke must first be placed in vertical position. 2. Front yoke of Rear Prop shaft is set horizontal as shown. Fig. 4A-19--Alignment for Phasing L IG H T T R U C K SERVIC E M A N U A L 4A-10 PROPELLER SHAFT WASHER SEAL TUBE BALL STUD YOKE COUPLING YOKE FLANGE YOKE Fig. 4A-20--Bearing Cap Removal Sequence socket is part of the flange yoke assembly, while the centering ball is pressed onto a stud and is part of the ball stud yoke. See figure 4A-22. Pry the seal from the ball socket and remove washers, spring and the three ball seats as illustrated in figure 4A-23. Fig. 4A-22--Cross Sectional View of CV Joint 1. Clean and inspect ball seat insert bushing for wear. If bushing is worn, replace flange yoke and cross assembly. 2. Clean and inspect seal and ball seats along with spring and washers. If any parts show indication of excessive wear or are broken, replace the entire set with a service kit. Whenever the seal is removed to inspect ball seat parts, it should be discarded and replaced with a new seal. 3. Remove all plastic from groove of coupling yoke. 4. Inspect the centering ball surface. If it shows signs of wear beyond smooth polish, replace it. Fig. 4A-23--Exploded View of Centering Ball Mechanism FLANGE YOKE COUPLING YOKE BALL SUPPORT TUBE YOKE ALIGNMENT PUNCH MARKS Fig. 4A-21--Reassembling Coupling Yoke LIGHT TRUCK SERVICE MANUAL Fig. 4A-24-lnstalling Tool J-23996 Over Ball PROPELLER SHAFT Fig. 4A-25--lnstalling Outer Cylinder of Tool J-23996 Over Ball Centering Ball Replacement 1. Place fingers of inner part of Tool J-23996 under ball as shown in figure 4A-24. 2. Place outer cylinder of Tool J-23996 over outside of ball as shown in figure 4A-25. 3. Thread nut on Tool J-23996 and draw ball off stud, using wrench as shown in figure 4A-27. 4. Place the replacement ball on stud. 5. Using Tool J-23996, drive ball onto stud as in figure 4A-27, until the ball can be seen to seat firmly against the shoulder at the base of the stud. This is important as the center of the double C ardan joint is determined by the ball seating tightly in the proper location. 6. Using grease provided in the ball seat kit, lubricate all parts and insert them into the clean ball seat cavity in the following order: spring, w asher (smallest O D ), three ball seats (with largest opening outw ard to receive ball), washer (largest OD) and seal. Fig. 4A-26--Removing Centering Ball 4 A -11 Fig. 4A-27--lnstalling Centering Ball 7. Lubricate seal lip and press seal flush with Tool J-23694, as shown in figure 4A-28. Sealing lip should tip inward. 8. Fill cavity with grease provided in kit. 9. Install flange yoke to centering ball as shown in figure 4A-29, making sure alignment marks are correctly positioned. Install trunnion and bearing caps as pre­ viously outlined. LUBRICATION The front axle propshaft found on all four-wheel drive trucks requires special lubrication procedures at two loca­ tions: The C /V joint, and the slip yoke. Constant Velocity Joints (C/V) T he constant velocity ( C /V ) joint, located at the transfer case end of the front propshaft, must be lubricated periodically (see Section 0) with special lubricant, # 1050679, or equivalent. If the fitting cannot be seen from beneath the vehicle Figure 4A-30 shows how the fitting may be lubricated from above the C /V joint, with a special adapter J -2 5 5 12-2 on the end of a flex hose. Fig. 4A-28--lnstalling Centering Ball Seal L IG H T TR U C K SE R V IC E M AN U AL 4A-12 PROPELLER SHAFT Fig. 4A-29--Reassembling Flange Yoke to disconnect the propshaft from the truck, remove the slip yoke, and wire brush the affected areas. Wipe clean before reinstallation. When installing the propshaft to transfer case front output flange attaching bolts, torque to specification 95-110 N-m (70-80 ft. lbs.). Slip Spline Apply chassis lubricant at the fitting until grease begins to leave through the vent hole. If the slip spline is dry or corroded, it may be necessary SPECIFICATIONS PROPELLER SHAFT CK G P P ro p e lle r S h a ft To R ear A x le (S tra p ) B e a rin g S u p p o rt-to -H a n g e r H a n g e r-to -F ra m e 1 2 -1 7 2 0 -3 0 4 0 -5 0 1 2 -1 7 2 0 -3 0 — 1 2 -1 7 2 0 -3 0 — To T ra n s fe r Case D a n a Style G M Style 2 0 -3 0 7 0 -8 0 T o rqu e Sp ecificatio ns (Ft.-Lbs.) LIGHT TRUCK SERVICE MANUAL REAR AXLE 4B-1 SECTION 4B REAR AXLE The following notice applies to one or more steps in the assembly procedure of components in this portion of the manual as indicated at appropriate locations by the terminology "See Notice on Page 1 of this Section ". N O T IC E : This fastener is an important attaching part in that it could affect the performance of vital components and systems, a nd/or could result in major repair expense. It must be replaced with one of the same part number or with an equivalent part if replacement becomes necessary. Do not use a replacement part of lesser quality or substitute design. Torque values must be used as specified during reassembly to assure proper retention of this part. CONTENTS General Description........................................................................................... Differential Diagnosis....................................................................................... General Diagnostic Procedure...................................................................... Differential and Rear Axle Bearing Diagnosis........................................ On Vehicle Serv ice............................................................................................ 8-1 /2 ", 8 -7 /8 ", and 9-1/2" Ring G e a r..................................................... Chevrolet 10-1/2" Ring G e a r ...................................................................... Dana 10-1/2" Ring G e a r ............................................................... .............. Dana 9 - 3 /4 "R ing G e a r .................................................................................. Chevrolet 12-1/4" Ring G e a r ...................................................................... Specifications...................................................................................................... Special Tools............................................................. ............ ...................... ...... 4B-1 4B-8 4B-8 4B-12 4B-14 4B-14 4B-18 4B-21 4B-21 4B-22 4B-24 4B-27 GENERAL DESCRIPTION A differential is an arrangement of gears that divides the torque between the axle shafts and allows them to rotate at different speeds. A basic differential consists of a set of four gears. Two of these gears are called differential side gears, and the other two are differential pinion gears. Some differentials have more than two pinion gears. Each side gear is splined to an axle shaft. Consequently, each axle shaft must turn when its side gear rotates. The differential pinion gears are mounted on a differ­ ential pinion shaft, and the gears are free to rotate on this shaft. The pinion shaft is fitted into a bore in the differential case and is at right angles to the axle shafts. Power flow through the differential is as follows: The drive pinion roates the ring gear. The ring gear, being bolted to the differential case, rotates the case. The differential pinion, as it rotates with the case, forces the pinion gears against the side gears. W hen both wheels have equal traction, the pinion gears do not rotate on the pinion shaft because the input force on the pinion gear is equally divided between the two side gears. See figure 4B-1. Consequently, the pinion gears revolve with the pinion shaft, but do not rotate around the shaft itself. The side gears, being splined to the axle shafts and in mesh with the pinion gears, rotate the axle shafts. If a vehicle were always driven in a straight line, the ring and pinion gears would be sufficient. The axle shaft could then be solidly attached to the ring gear and both driving wheels would turn at equal speeds. However, if it became necessary to turn a corner, the tires would scuff and slide because the outer wheel would travel further than the inner wheel To prevent tire scuffing LIG H T T R U C K SE R V IC E M AN U AL 4B-2 REAR AXLE carrier near the axle tubes. Backlash is adjusted by increas­ ing or decreasing shim thickness. Chevrolet 10-1 /2" Ring Gear Axle The axle shown in figure 4B-5 is of the full floating type with hypoid ring gear and drive pinion. The full floating construction enables easy removal of axle shafts w ithout removing truck load and w ithout jacking up the axle. The differential carrier is heavily ribbed to provide rigid support for the differential assembly. The straddle-m ounted drive pinion is supported at the front by two opposed tapered roller bearings. The pinion straddle bearing is a roller bearing assembly consisting of an outer race and roller assembly. A precision ground diam eter on the pinion pilot functions as an inner race. and sliding, the differential becomes effective and allows the axle shafts to rotate at different speeds. As the inner wheel slows down, the side gear splined to that axle shaft also slows down. A t this point, the pinion gears act as balancing levers by m aintaining equal speeds of rotation of the axle shafts. See figure 4B-2. If the vehicle speed rem ains constant and the inner wheel slows to 90% of vehicle speed, the outer wheel speeds up to 110%. If the inner wheel slows to 75%, the outer wheel would turn 125%. If one wheel stopped, the other wheel would turn 200%. Seven d istin ct axles com prom ise th e tru ck line-up. These six, categorized by ring gear diam eter, are a) 8-1/2" and b) 8 -7 /8 " Ring G ear, c) Chevrolet 9 -1 /2 " 10-1/2" Ring G ear, d) D ana 10-1/2" Ring G ear, e) D ana 9-3/4" Ring G ear and f)Chevrolet 12-1/4" Ring G ear. 8 -1/2", and 8-7/8" and 9 -1/2 " Ring Gear Axle The axle shown in figure 4B-3 and 4B-4 is a semifloat­ ing, fabricated constructed type consisting of a cast carrier with large bosses on each end into which two welded steel tubes are fitted. The carrier contains an overhung hypoid pinion and ring gear. T he d ifferential is a two pinion arrangem ent. The axle housing is m ade up of two steel welded tubes pressed into the crossbore of the cast carrier. Each tube is puddle welded to the carrier. W elded-on brackets provide a tta ch m e n t points for suspension com ponenets such as shock ab sorbers and leaf springs. A welded flange is provided for brake flange plate attachm ent. An overhung hypoid drive pinion is supported by two preloaded tapered roller bearings. The pinion shaft is sealed by means of a molded, spring loaded, rubber seal. The hypoid ring gear is bolted to a one-piece differential case which is supported by two preloaded tapered roller bearings. On th e 9 1 /2 " ring gear side bearing preload is controlled by a side bearing adjusting nut threaded into the LIGHT TRUCK SERVICE MANUAL Side bearing preload and ring gear-to-pinion backlash are controlled by side bearing adjusting nuts threaded into the carrier near the axle tubes. Pinion depth is controlled by a shim located between the pinion bearing retainer assembly and the differential carrier. Dana 10-1 /2" Ring Gear Axle The Dana axle shown in figure 4B-6 is a Salisbury-type sim ilar in design to the 8 -7 /8 " ring gear axle in figure 4B-4. It does differ in several points, however. The axle shafts are full floating; the carrier m ust be spread to remove the differential; and the drive pinion incorporates two shim packs. The inner pack controls pinion depth, while the outer pack controls pinion bearing preload. Dana 9-3/4" Ring Gear Axle The D ana axle shown in figure 4B-7 is sim ilar to the unit shown in 4B-6; however, the differential side bearing shims are located between the case and the side bearings. Chevrolet 12-1 /4" Ring Gear Axle (11,000 Pound Capacity) The 11,000 lb. capacity, single-speed hypoid axle, illustrated in figure 4B-8, has a straddle m ounted drive pinion which is supported at the rear by a straight roller bearing. The pinion front bearing consists of a double row ball bearing. T he differential is a conventional four-pinion type. T hrust washers are used between the side gears and case and also between differential pinions and the differential case. A thrust pad m ounted on the end of an adjusting screw threaded into the carrier housing limits deflection of the ring gear under high torque conditions. Involute splines are incorporated in th e axle shaft flange and in the wheel hubs. This design provides for the driving torque to be transm itted from the axle shaft to the hub through the m ating splines. REAR AXLE 1. C om panion Flange 7. D iffe r e n tia l Case 13. C over 19. 2. D e fle c to r 8. Shim 14. P inion S haft 2 0 . D iffe r e n tia l Pinion 3. Pinion O il Seal 9. G a sket 15. Ring G e a r 2 1 . Shim 4. Pinion Front Bearing 10. D iffe r e n tia l Bearing 16. Side G e a r 2 2 . Pinion Rear Bearing 5. Pinion Bearing Spacer 11. " C " Lock 17. Bearing C a p 2 3 . D riv e Pinion 6. D iffe r e n tia l C a rr ie r 12. Pinion Shaft Lock 18. A x le Shaft Screw Fig. 4B-3--8-1 /2 " and 8 -7 /8 " Ring Gear Axle Cross-Section Typical Thrust W asher 4B-3 4B-4 •J9HT REAR AXLE U&mg W i REAR AXLE 1. 2. 3. 4. 5. 6. 7. 8. 9. C o m p a n i o n F la n g e O il D e f le c to r Oil Seal B e arin g R eta ine r S h im P in io n F r o n t B e a r in g C o lla p s i b le Sp a ce r P in io n R ear B e a r in g D rive P in io n 10. 11. 12. 13. 14. 15. 16. 17. 18. S t r a d d le Be arin g R in g Gear D iff e re n tia l S p i d e r D iff e re n tia l C ase D iff e re n tia l P i n io n D iff e re n tia l S id e G e a r S id e B e a r in g S id e B e a r i n g A d j u s t i n g N u t A d j u s t i n g N u t R eta in e r 4B-5 19. R e ta in e r S c r e w 20. B e a r i n g C a p 21. C a s e - t o - R i n g G e a r B o lt 22. D iff e re n tia l C o v e r 23. B e a r in g C a p B o lt 24. C o v e r S c r e w 25. A x l e S h a f t Fig. 4B-5~Chevrole t 1 0 -1 /2 " Ring G ear Axle C ro ss-Se ction LIGHT TRUCK SERVICE MANUAL 4B-6 REAR AXLE P inion N ut Washer Com panion Flange O il Seal O il Slinger P inion F ro n t Bearing F ro n t Bearing Cup Preload Shim Pack P inion D epth Shim Pack Rear Bearing Cup 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. Pinion Rear Bearing Drive Pinion Ring Gear D iffe re n tia l Case Ring Gear B o lt D iffe re n tia l Side Bearing Side Bearing Cup Side Bearing A dju stin g Shims Bearing Cap Bearing Cap B o lt Fig. 4B-6--Dana 10-1 / 2 " Ring Gear Axle Exploded View LIGHT TRUCK SERVICE MANUAL 21. 22 . 23. 24. 25 26. 27. 28. 29. D iffe re n tia l Spider D iffe re n tia l Side Gear Washer P inion Gear Washer Gasket Cover Cover Screw Drain Plug REAR AXLE 1. Nut 2. Washer 3. Companion Flange 4. Pinion Oil Seal 5. Gasket 6. Outer Pinion Oil Slinger 7 and 8. Cone and Roller (Outer Pinion Bearing) 9. Shims (Outer Pinion Bearing) 10. Inner Pinion Oil Slinger 11. Shims (Inner Pinion Bearing) 12. Cup (Inner Pinion Bearing) 13. Cone and Roller (Inner Pinion) 14. Ring and Pinion 15. Gasket (Housing Cover) 16. Screw and Washer (Cover) 17. 18. 19. 20. 21. 22. 23. Cover and Plug Lock Pin (Pinion Shaft) Differential Case Shims (Differential Adjusting) Cone and Roller (Differential Bearing) Cup (Differential Bearing) Cap (Differential Bearing) 24. 25. 26. 27. 28. 29. 30. 4B-7 Bolt (Differential Bearing Cap) Bolt (Ring Gear) Pinion Shaft Thrust Washer (Pinion) Pinion Side Gear Thrust Washer (Side Gear) Fig. 4B-7--Dana 9 -3 /4 " Ring Gear Axle Exploded View LIGHT TRUCK SERVICE MANUAL 4B-8 REAR AXLE 1. U n iversal J o in t Yoke 2. Pinion B e aring Oil Seal and R e tainer 3. 4. 5. 6. 7. O il Seal O il S e al G asket Front Pinion Bearing D rive Pinion R ear Pinion Bearing Ring G ear T hrust Pad 14. A xle S h aft 9. 10. 11. Ring G ear D iffe re n tia l S p ider D iffe re n tia l Pinion 15. 16. 12. 13. (S pider) G ear D iffe re n tia l S ide G ear D iffe re n tia l C a s e -L e ft 17. 18 D iffe re n tia l B earing D iffe re n tia l Bearing A d ju s tin g Nut A d ju s tin g N u t Lock D iffe re n tia l C a s e -R ig h t H alf 8. H alf Fig. 4B-8--Chevrolet 1 2 -1 /4 " Ring Gear A xle-11,000# Capacity DIFFERENTIAL DIAGNOSIS STANDARD DIFFERENTIAL Noise The most essential part of rear axle service, as with any mechanical repair, is proper diagnosis of the problem, and, in axle work one of the most difficult areas to diagnosis is noise. Locating a broken axle shaft, or broken differential gear, presents little or no problem , but, locating and isolating axle noise can be an entirely different m atter. Degree of Noise Any gear driven unit, and especially an automotive drive axle where engine torque m ultiplication occurs at a 90° turn in the drive line, produces a certain am ount of noise. Therefore, an interpretation m ust be m ade for each LIGHT TRUCK SERVICE MANUAL vehicle to determ ine w hether the noise is normal or if a problem actually exists. A norm al am ount of noise must be expected and cannot be elim inated by conventional repairs or adjustm ent. See figure 4B-9. A cceptable noise can be defined as a slight noise heard only at a certain speed or under unusual or rem ote condi­ tions. For example, this noise tends to reach a "p eak " at speeds from 40 to 60 miles per hour (60 to 100 km /h) depending on road and load conditions, or on gear ratio and tire size. This slight noise is in no way indicative of trouble in the axle assembly. Drive line noises may baffle even the best diagnostician. Vehicle noises coming from tires, transm ission, propeller shaft, universal joints, and front or rear wheel bearings, are REAR AXLE SOME A/O/SE / S \ ACCEPTABLE \< » O ri' ■— Ov £ (X BOLT TORQUES (FT.-LBS.)A G ear Backlash Preferred .005"- .005".008" .008" .005"- .004"- .005"- .005".008"- .009" .008" .008" Filler Plugs Min. and Max. .003"- .003".010" .010" .003*'- .004"- .003"- .003".010"- .009" .012" .012" Differential Pinion Lock Pinion Bearing Preload (In.-Lbs.) — New — Used 15-30 15-30 20-25 20-40 25-35 5-10 5-10 5-15 10-20 5-15 Carrier Cover 20 20 20 35 30 Ring G ear 80 60 110 110 120 Differential Bearing Caps 55 55 65 85 135 AExcept where noted otherwise. Chevrolet 05 0 c 0 a i O rf' — o- 00 £ oo IOV 2 " £ 00 Chevrolet 00 0 c 0 O lO W ' DIFFERENTIAL SPECIFICATIONS £ CN 25 18 18 10 18 10 2 0"# 2 0"# — — — — 220 o. Drive Pinion Nut — * * * Differential Carrier to Axle Housing — — — — 85 Differential Bearing Adjusting Lock — 20 — 20 15 Pinion Bearing Cage To Carrier — — — 65 165 — — — — 135 35 105 105 105 155 — — 115 115 15 — Thrust Pad Lock Nut 105 Brake Backing Plate 205 Axle Shaft To Hub Bolts 35 *T orque as necessary to obtain correct preload. Ring Gear Size Lubricant Capacity 8 V2 " 4.2 Pints 8% " 3.5 Pints Chevrolet 10'/j" 5.4 Pints Dana 10 V2 " 7.2 Pints Dana 9 % " 6.0 Pints 12>/4" 14.0 Pints Chevrolet 9 V i" 5.5 Pints Specifications Chart 4B-A LIGHT TRUCK SERVICE MANUAL 4B-26 REAR AXLE RING GEAR SIZE SOURCE TYPE/CAPACITY CIO C h e v ro le t S a lis b u r y /3 7 5 0 # 8 -7 /8 " C10 C h e v ro le t S a lis b u ry /3 7 5 0 # 8-1/2" K10 C h e v ro le t S a lis b u ry / 3 7 5 0 # 8 -1 /2 ” K10 C h e v ro le t S a lis b u r y /3 7 5 0 # 8 - 7 /8 ” K10 C h e v ro le t S a lis b u r y /4 0 0 0 # 8 - 7 /8 ” P10 C h e v ro le t S a lis b u r y /3 5 0 0 # 8 -7 /8 " G10 C h e v ro le t S a lis b u r y /3 5 0 0 # 8 -7 /8 " G10 C h e v ro le t S a lis b u r y /3 5 0 0 # 8 -1 /2 " MODEL C20 (Except Crew Cab) C h e v ro le t S a lis b u r y /6 0 0 0 # 9 -1 /2 ” C20 (Crew Cab) C h e v ro le t S a lis b u r y /7 5 0 0 # 1 0 - 1 /2 " K20 C h e v ro le t S a lis b u r y /6 0 0 0 # 9 -1 /2 " P20 C h e v ro le t S a lis b u r y /6 0 0 0 # 9 -1 /2 ” G20 C h e v ro le t S a lis b u r y /3 5 0 0 # 8 -7 /8 " G20 C h e v ro le t S a lis b u ry /3 5 0 0 # 8 -1 /2 " C h e v ro le t S a lis b u r y /7 5 0 0 # 1 0 - 1 /2 " Dana S a lis b u r y /7 5 0 0 # 1 0 - 1 /2 " C h e v ro le t S a lis b u r y /7 9 0 0 # 1 0 - 1 /2 " C h e v ro le t B a n jo /1 1 , 0 0 0 # 1 2 - 1 /4 " C h e v ro le t S a lis b u r y / 5 7 0 0 # 1 0 - 1 /2 " Dana S a lis b u r y /6 2 0 0 # 9 -3 /4 " D ana S a lis b u r y /7 5 0 0 # 10 1 /2 " C30 K30 (Except Dual Wheel Camper) C30 *Dual K 3o yyheel . Camper) P30 P30 (With H22/H23) G30 030 __n 030 (Dual Wheel) (Dual Wheel) REAR WHEEL BEARING ADJUSTMENT SPECIFICATION RING GEAR SIZE 10-1/2” 9-3/4” BEARING ADJUSTING NUT TORQUE* 50 FT. LBS. 50 FT. LBS. 12-1/4” 90 FT. LBS. ADJUSTING NUT BACK-OFF* OUTER LOCKNUT TORQUE RESULTING BEARING ADJUSTMENT TYPE OF BEARING ** 65 FT. LBS. .001 TO .010 END PLAY TAPERED ROLLER SLIGHT PRELOADED BARREL ROLLER 1/8 * 250 FT. LBS. **B a ck-o ff n ut and retighten to 35 Ft. Lbs. then, back-off nut 1/4 turn. *W ith wheel rotating. Specifications Chart 4B-A2 LIGHT TRU CK SERVICE MANUAL REAR AXLE 4B-27 SPECIAL TOOLS *§> A 10 ’-"■v >•p ■.Avfi:', 11 13 H* 16 w m 17 ° I 19 20 21 22 1OV2 " R.G. A X L E O N L Y 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. J-2 15 4 8 J-2 36 9 0 J-2 36 8 9 J-21128 J-21057 J-22804-1 J-5 74 8 J-6 62 7 J-8 09 2 J -5 8 5 3 J-8 61 4 -II 12. J-2 61 9 13. J-2 22 2 14. J-2 44 2 9 15. J-2 44 3 3 T ru n n io n Seal In sta lle r A x le S h a ft Bearing In sta lle r A x le S h a ft Bearing R em over A x le S h a ft Seal In sta lle r P in io n O il Seal In sta lle r P inio n Seal Gauge Plate P o s itra c tio n T o rq u e Measuring A d a p te r Wheel B o lt R em over D rive r H andle T o rq u e W rench - In ch /P o u n d C om p a n io n Flange H o ld e r S lid e H am m er Wheel Bearing N u t W rench A d ju s tin g N u t W rench P inio n Rear Bearing In sta lle r 16. 17. 18. 19. 20. J-2 44 3 0 J-2 3 3 2 2 J-2 44 2 6 J-2 4 4 3 2 J-24427 21. J-8 60 8 22. J-2 43 8 4 23. J-2 44 2 8 24. J-2 4 4 3 4 D iffe re n tia l Side Bearing In s ta lle r P in io n S tra d d le B earing In s ta lle r O u te r W heel P in io n Rear In n e r W heel O u te r W heel B earing C up Bearing C up Bearing C up Bearing C up Tool In s ta lle r In s ta lle r In s ta lle r P in io n O il Seal In s ta lle r - Dana Wheel H u b O il Seal In sta lle r P in io n O il Seal In s ta lle r - C h e v ro le t W heel B earing N u t W rench 25. J-870 26. J-2 23 8 0 27. J -2 2 3 5 4 T ru -A rc Pliers W heel O il Seal In s ta lle r 28. J-22281 29. J-8 11 4 30. J-8 09 3 P in io n O il Seal In sta lle r Wheel Bearing O u te r C up In s ta lle r Wheel Bearing In n e r C up In s ta lle r Fig. 4B-42--Special Tools LIGHT TRUCK SERVICE MANUAL 1* :« v : m «KI # ; ##■ ----------- . fiOieM 3 '"f.girji" .•■ I*.,. H'9& - f 1? ■ j -as? jV-iit .,•■ . w v^-S .' j*; 0 f .r *!*■' i-, ■ •' •h''.-:’ ii I f . .'V- ■ , j.i:S . '■..••• '.0 pic I* . .-I no;h m u.:>o ■ ii.cC r ‘ .*m • f!fe'ft,'.nVV i ii ■.• I bP| 'l^ifjr' -• Vr. "V.- '•ij>N f. ifi’-' ' 4 :, FRONT WHEEL DRIVE 4C-1 SECTION 4C FRONT WHEEL DRIVE The following notice applies to one or more steps in the assembly procedure of com ponents in this portion of the m anual as indicated at appropriate locations by the terminology "See N otice on page 1 of this S ection". N O TICE: This fastener is an im portant attaching part in th at it could affect the perform ance of vital components and systems, a n d /o r could result in m ajor repair expense, it m ust be replaced with one of the same part num ber or with an equivalent part if replacem ent becomes necessary. Do not use a replacem ent part of lesser quality or substitute design. Torque values m ust be used as specified during reassem bly to assure proper retention of this part. CONTENTS G eneral D escription...................................................... .................................... 4C-1 Front Axle A ssem bly................................. ...................................................... 4C-1 R em o v al....................................................................... ..................................... 4C-1 In stallatio n ........................................ ............................. .................................. 4C-1 D iagnosis.............................................................................................................. 4C-2 R epair Axle Joint C om ponents...................................................................... 4C-3 Specifications.......................................................... ........................................... 4C-4 GENERAL DESCRIPTION The front axle is a hypoid gear axle unit equipped with steering knuckles. Axle assembly num ber and production date are stam ped on left tube of assembly. K 10-20 M odels use a C hevrolet front axle, both incorporate a 8-1/2" ring gear. A 4500 lb. capacity unit is used on the K-30 Model. The K-30 axle assembly is a Dana (60 Series) which incorporates a 9 -3 /4 " ring gear. 1. Install seal and thru st w asher on axle shaft. 2. Install axle shaft into axle housing. 3. Install spindle. 4. Install splash shield. Torque nuts to specifications. 5. Install rotor and adjust wheel bearings. 6. Install gears and snap rings. 7. Install hub lock mechanism. Axle Shaft Removal 1. Syp h on m aster cylinder. 2. 3. 4. 5. 6. 7. 8. 9. 10. Raise vehicle. Remove wheel and tire. Remove caliper. Remove hub lock mechanism. Remove gears and snap rings. Remove rotor. Remove inner bearing and seal. Remove spindle and backing plate. Remove axle shaft. 8. Install caliper. 9. Install tire and wheel. 10. Lower vehicle. 11. Add fluid and check brake operation. FRONT AXLE ASSEMBLY (Refer to Fig. 4C-2) Removal 1. Raise front of vehicle on hoist until weight is removed from front springs. Support truck with jack stands behind front springs. 2. Disconnect propeller shaft from front axle differential. 3. Disconnect connecting rod from steering arm . 4. Remove and support caliper. Installation 5. Disconnect shock absorbers from axle brackets. Prior to installation, the following items should be checked. a. Lube spindle bearing. b. Clean, inspect and repack inner and outer wheel bearing. 6. D isconnect axle vent tube clip a t the differential housing (see fig. 4C-3). c. Clean hub and spindle and lube spindle. 7. Dismount " U " bolts from axle to separate axle from truck springs. 8. Raise truck to clear axle assembly and roll front axle out from under the truck. LIGHT TRUCK SERVICE MANUAL 4C-2 FRONT WHEEL DRIVE BEARINGS AND RACES FRONT WHEEL, PINION, DIFFERENTIAL SIDE AND REAR WHEEL ROLLER BEARINGS DIAGNOSIS EXCESS NOISE C O M PLA IN T DIAG NO STIC PROCEDURE Road Test 1. 2. 3. 4. 5. Tire Noises 1. 2. 3. 4. 5. Engine or Exhaust Noises Test for Wheel Bearing Noise Test for Differential Bearing Noise Test for Pinion Bearing Noise 1. 2. 3. 4. 1. 2. 3. 4. 1. 2. 3. 4. 1. 2. 3. 4. 5. 6. 7. Check tires for irregular wear Check tire pressure Check lubricant level D rive to w a rm -u p f r o n t axle Test at various speeds in drive, float, coast and cornering Change tire pressure to minimize noises Drive over different road surfaces Sm ooth black-top minimizes tire noise Cross switch tires, if necessary Snow tire treads and studs caused added noises Drive slightly above speed where noise occurs, place transmission in neutral Let engine speed drop to idle Stop car Run engine at various speeds Drive car at low speed on a sm ooth road Turn car to develop left and right m otions, traffic perm itting Noise should change due to cornering loads Jack-up wheels to verify roughness at wheels Drive car at low speed on a sm ooth road C onstant low pitch bearing noise may be heard Noise should not change in reversing turns Noise pattern should vary with wheel speed Roughness or whine noise should increase with speed Noise pitch should be higher than differentials Test on sm ooth road to minimize tire noises Test at various speeds in drive, float, and coast Rear pinion bearing noise may be louder on acceleration F ront pinion bearing noise may be louder on deceleration Gear noises tend to peak in a narrow speed range Fig. 4C-1 --Bearing Diagnosis Installation NOTICE: See N O T IC E on page 1 of this section 1. 2. 3. 4. regarding the fasteners referred to in steps 3, 5 ,6 and 8. Truck should be on jack stands as in Step 1 of removal instructions. Place axle in position under truck. Install " U " bolts attaching axle to front springs. A ttach shock absorbers to axle brackets. LIGHT TRU CK SERVICE MANUAL 5. 6. 7. 8. 9. Install caliper (see Section 5). A ttach connecting rod to steering arm . Remove jack stands and lower front of truck. Assemble propeller shaft to front axle differential. Lower vehicle to floor. FRONT WHEEL DRIVE 4C-3 Fig. 4C-2~Front Drive Axle Typical Disassembly R efer to S ection 3C for hub, spindle and knuckle removal and installation procedures. 1. Securely m ount the axle assembly in a suitable holding fixture. 2. Remove autom atic hub lock. (See Section 3C). 3. Remove the wheel bearing outer lock nut, lock ring, and wheel bearing inner adjusting nut as outlined in Section 3C. 4. Remove the disc assembly outer wheel bearing and the spring retainer plate. If the disc or other brake com ponents require repairs or replacem ent, refer to Section 5. Repair The Axle Joint Components: 1. Remove the lock rings after removing pressure from the trunnion bearings by squeezing the ends of the bearing in a vise. 2. Support the shaft yoke in a bench vise or on a short length of pipe. 3. Using a brass drift and a soft ham m er, drive on end of one trunnion bearing ju st far enough to drive opposite bearing from yoke. 4. Support the other side of the yoke in the vise and drive the other bearing out by tapping on the end of the trunnion using a brass drift. 5. Remove trunnion. 6. Clean and inspect bearings. Lubricate with a high melting point type wheel bearing grease. 7. Replace trunnion and press new or relubricated bear­ ings into yoke and over trunnion hubs far enough to install lock rings. 8. Hold trunnion in one hand and tap yoke lightly to seat bearings against lock rings. Assembly Reverse disassembly procedure. LIGHT TRU CK SERVICE MANUAL 4C-4 FRONT WHEEL DRIVE SPECIFICATIONS CHEVROLET Axle G ear and Backlash Preferred Min. and Max. New Pinion Bearing Preload Used Pinion Bearing Preload Bolt Torques (Ft.-Lbs.) Axle .005-.008 .003-.010 15-30 in.-lbs. 5-10 in.-lbs. C arrier Cover Ring G ear Differential Bearing Caps Filler Plugs Bolt Torques (Ft.-Lbs.) 20 80 55 25 DANA Axle Gear Backlash Preferred Min. and Max. New Pinion Bearing Preload Used Pinion Bearing Preload Bolt Torques (Ft.-Lbs.) .004"-. 009" .004"-.009" 20-40 in.-lbs. 10-20 in.-lbs. Axle Carrier Cover Ring Gear* — K-30 Differential Bearing Caps Filler Plugs Drive Pinion Nut** — K-30 Specification Chart 4C-1 LIGHT TRUCK SERVICE MANUAL Bolt Torques (Ft.-Lbs.) 35 110 85 10 270 BRAKES 5-1 SECTION 5 BRAKES T he following notice applies to one or more steps in the assembly procedure of com ponents in this portion of the m anual as indicated at appropriate locations by the term inology "See N otice on page 1 of this section ". N O TICE: This fastener is an im portant attaching p art in th a t it could affect the perform ance of vital components and systems, an d /o r could result in m ajor repair expense. It m ust be replaced with one of the same part num ber or with an equivalent p art if replacem ent becomes necessary. Do not use a replacem ent p art of lesser quality or substitute design. Torque values m ust be used as specified during reassem bly to assure proper retention of this part. C A U TIO N : W hen servicing wheel brake parts, do not create dust by grinding or sanding brake linings or by cleaning wheel brake parts with a dry brush or with compressed air. (A w ater dam pened cloth should be used.) M any wheel brake parts contain asbestos fibers which can become airborne if dust is created during servicing. Breathing dust containing asbestos fibers m ay cause serious bodily h a rm ." CONTENTS G eneral D escrip tio n ............................................................ Diagnosis................................................................................ On-V ehicle Service.............................................................. Pedal T ravel...................................................................... Stop L ight S w itc h ........................................................... Bleeding and Flushing B ra k e s..................................... Hydro-Boost Bleeding P ro c e d u re ............................... Brake P ip es....................................................................... Brake H oses.......................................................... ........... Parking Brake Pedal or H a n d le .................................. Parking Brake (Propshaft) Internal E xpanding...... Parking Brake C a b le ...................................................... C om bination V a lu e ........................................................ Brake P e d a l...................................................................... Brake Pedal R o d ............................................................. M aster C y lin d er.............................................................. 5-1 5-2 5-10 5-10 5-10 5-10 5-12 5-17 5-17 5-21 5-21 5-22 5-22 5-22 5-23 5-24 Delco Disc Brake Shoe and Lining..............................5-29 Bendix Disc Brake Shoe and Lining.......................... .5-34 C aliper O v erh au l..............................................................5-36 Rotor Servicing................................................................ .5-39 Brake D rum Shoe and L ining...................................... .5-39 Standard D rum B rake............................................... .5-39 Propeller Shaft B rake................................................ .5-42 Brake D ru m s .....................................................................5-43 W heel C y lin d e r............................................................... .5-43 Power Brake U n it.............................................................5-46 Vacuum B ooster......................................................... .5-46 Hydro-Boost U n it....................................................... .5-46 Specifications........................................................................ .5-53 Brake System D escription............................................ .5-53 Torque Specifications......................................................5-54 Special Tools........................................................................ ..5-55 GENERAL DESCRIPTION OPERATION OF MASTER CYLINDER W hen the brake pedal is depressed, force is transferred through the push rod to the m aster cylinder prim ary piston, which moves forw ard. U nder norm al conditions, the com­ bination of hydraulic pressure and the force of the prim ary piston spring move the secondary piston forw ard a t the same time. W hen th e pistons have moved forw ard so th at their prim ary cups cover the bypass holes, hydraulic pressure is b u ilt up and tra n sm itte d to the fro n t and re a r brake assemblies. H ydraulic pressure behind the wheel cylinder cups forces the pistons outw ard, causing the brakes to be applied. As brake pedal force is reduced, brake fluid pressure in the m aster cylinder is also reduced. This allows the drum brake re tra c to r springs to re tra c t the shoe and lining assemblies from contact with the drum which forces brake fluid out of the wheel cylinder assemblies and back into the m aster cylinder assembly. The reduction in fluid pressure also allows the caliper pistons to retract slightly by action of the piston seal. M aster cylinders designed for use w ith a system incorporating low drag calipers. In addition to the standard m aster cylinder functions, a quick take-up fea tu re is included. This provides a large volume of fluid to the wheel brakes at low pressure with initial brake application. The low pressure fluid quickly provides the displacem ent re­ quirem ents created by the seal retracting pistons into the front calipers and spring retraction of the rear drum brake shoes. LIGHT TRUCK SERVICE MANUAL 5-2 BRAKES OPERATION OF DISC BRAKE Upon application of the brakes, fluid pressure behind the caliper piston increases. Pressure is exerted equally against the bottom of the piston and also against the bottom of the piston bore. The pressure applied to the piston is transm itted to the inner shoe and lining, forcing the lining against the inner rotor surface. The pressure applied to the bottom of the piston bore forces the caliper to slide or move on the mounting bolts tow ard the inner side, or toward the vehicle. Since the caliper is one piece, this movement toward the vehicle causes the outer section of the caliper to apply pressure against the back of the outer shoe and lining assembly, forcing the lining against the outer rotor surface. As line pressure builds up, the shoe and lining assemblies are pressed against the rotor surfaces with increased force, bringing the vehicle to a stop. Lining wear is autom atically com pensated for by the outw ard movement of the caliper and piston. Brake fluid fills this void as lining wears. OPERATION OF COMBINATION VALVE The m etering or hold off section of the com bination valve limits pressure to the front disc brakes until a pre­ determ ined front input pressure is reached, approxim ating the pressure to overcome the rear shoe and lining retractor springs. There is no restriction a t inlet pressures below 21 kPa (3 psi) to allow for pressure equalization during non apply periods. The proportioning section of the combination valve proportions outlet pressure to the rear brakes after a pre­ determ ined rear input pressure has been reached. This is done to prevent rear wheel lock-up on vehicles with light rear wheel loads. C ertain models having high rear wheel loads do not have the proportioning feature. The valve is designed to have a "B y-Pass" feature which assures full system pressure to the rear brakes in the event of a front brake system failure. Full front pressure is retained in the event of rear failure. The pressure differential w arning switch is designed to constantly com pare front and rear brake pressure from the m aster cylinder and energize the warning light on the dash in the event of a front or rear system failure. The valve and switch are so designed th at the switch will latch in the "w arning" position once a failure has occurred. The only way the light can be turned off is to repair the failure and apply a pedal force as required to develop up to 3100 kPa (450 psi) line pressure. DIAGNOSIS INSPECTION AND TESTING BRAKES Testing Brakes 4. Front End Alignment—M isalignm ent of the front end, particularly in regard to limits on cam ber and theoreti­ cal king pin inclination, will cause the brakes to pull to one side. New linings m ust be protected from severe use for several hundred miles. Brakes should be tested on dry, clean, reasonably smooth and level roadway. A tru e test of brake perform ance cannot be m ade if roadw ay is wet, greasy or covered with loose dirt so th a t all tires do not grip the road equally. Testing will also be adversely affected if roadway is crowned so as to throw weight of vehicle tow ard wheels on one side or if roadway is so rough th a t wheels tend to bounce. Test brakes at different vehicle speeds with both light and heavy pedal pressure; however, avoid locking the wheels and sliding the tires on roadway. Locked wheels and sliding tires do not indicate brake efficiency since heavily braked but turning wheels will stop vehicle in less distance than locked wheels. M ore tire-to-road friction is present with a heavily braked turning tire th an with a sliding tire. External Conditions that Affect Brake Performance 1. T ires—Tires having unequal contact and grip on road will cause unequal b raking. T ires m ust be equally inflated and tread p attern of right and left tires m ust be approxim ately equal. 2. Vehicle Loading—W hen vehicle has unequal loading, the most heavily loaded wheels require more braking power th an others. A heavily loaded vehicle requires more braking effort. 3. Front W heel Bearings—A loose front wheel bearing perm its the drum to tilt and have spotty contact with the brake shoe linings causing e rratic action. LIGHT TRU CK SERVICE MANUAL HYDRO-BOOST Prior to perform ing the Booster Function Tests, or the A ccum ulator L eakdow n T est, th e following prelim inary checks m ust be made: 1. 2. 3. 4. 5. 6. NOTICE: Power steering fluid and brake fluid cannot be mixed. If brake seals contact steering fluid or steering seals contact brake fluid, seal dam age will result. Check all power steering and brake lines and connec­ tions for leaks and/or restrictions. Check and fill brake m aster cylinder with B R A K E FL U ID . Check and fill power steering pum p reservoir with P O W E R S T E E R IN G FL U ID . Be sure fluid is not aerated (air mixed with fluid). Check power steering pum p belt for tension an d /o r dam age. A djust if necessary. Check engine idle speed and adjust if necessary. Check steering pump pressure; R efer to Section 3B. SEAL LEAK DIAGNOSIS (FIG. 5-1) 1. IN P U T R O D SEAL: A dam aged seal will show up as a fluid leak from the m ounting bracket vent hole. The booster m ust be removed from the vehicle and disas­ sembled. The input rod bore should be checked for any scratches th at may cause the leak. If scratches are present, housing cover m ust be replaced. If no excessive scratches are present, then the booster seal kit can be used to replace the appropriate seals. BRAKES 5-3 HYDRO— BOOST SEAL LEAKAGE A. INPUT SEAL LEAK — Fluid leakage from housing cover end of booster near reaction bore. Replace seal(s). B. PISTO N SEAL LEAK — Fluid leakage from vent at front e# unit near master cylinder. Replace seal. C. H O U S IN G — Fluid leakage between the housing and housing cover. Replace seal. D. SPO O L VALVE SEAL — area. Replace seal. Fluid leakage near plug E. A C C U M U LA TO R CAP SEAL — Fluid leakage from accumulator area. Replace seal. F. RETURN PORT FITTING SEAL — Replace seal. Fig. 5-1--Seal Leakage Diagnosis 2. P O W E R P IS T O N SEA L: Power piston seal dam age will be noticed by fluid leaking out at the common m aster cylinder-brake booster vent and possible reduc­ tion in power assist. The booster m ust be removed from the vehicle and disassem bled. The piston should be checked for any scratches th a t m ay be the cause of the leak. If scratches are present, then the input rod and power piston assembly m ust be replaced. If no excessive scratches are present, then the booster seal kit can be used to replace the appropriate seals. 3. H O U S IN G SEA L: If the housing seal is dam aged, fluid will leak out from between the two housings. The booster must be removed from the vehicle and disas­ sembled. The booster seal kit should be used to replace the housing and input rod and power piston seals. 4. SPO O L V A LV E PL U G " O " R IN G SEAL: D am age to this seal will be noticed by fluid leaking out past the plug. T he booster need not be rem oved from the vehicle. The m aster cylinder should be disconnected from the booster. Press in on spool plug, in sert a sm all screw driver between snap ring and housing bore. This unseats one side of the spool plug snap ring from its groove in the bore. Then remove the snap ring from the bore. 5. A C C U M U L A T O R " O " R IN G SEA L: Dam age to this seal will result in fluid leakage past the accum ula­ tor cap. The seal can be replaced while the booster is installed on the vehicle. A catch basin should be placed under the booster to catch the fluid when the accum ula­ tor or spring cap is removed. CAUTIONhBefore removing the cap, the brake pedal must be pumped 4-5 times to deplete accumulator pressure. Refer to "Pneumatic Accu­ mulator On-Vehicle Service Procedure". 6. E X T E R N A L L E A K A G E A T T H E R E T U R N PO R T F IT T IN G : Tighten fitting to 7 lb. ft. (10 N -m ). If it continues to leak, replace "O " ring under fitting. 7. E X T E R N A L L E A K A G E A T T H E H IG H P R E S ­ S U R E G E A R O R PU M P: T orque tube nut to 30 lb. ft. (40 N-m ). If it continues to leak, check for dam aged tube flares; if OK, replace tube seats. TROUBLE SHOOTING AND TESTING (Fig. 5-2) The Hydro-Boost differs from vacuum brake boosters not only in the source of power (hydraulic versus vacuum ) but in the fact th at it is also a part of another m ajor sub­ system of the v e h icle-th e power steering system. Therefore, problems or m alfunctions in the steering system may affect the operation of the booster, ju st as a problem in the booster may affect the steering system. The following noises are associated with the H ydro-boost system and m ay or m ay not be cause for custom er com plaint. Some are norm al and for the most part tem porary in nature. O thers may be a sign of excessive wear or the presence of air in either the booster or the steering system. 1. M oan or low frequency hum usually accom panied by a vibration in the pedal an d /o r steering column m ay be observed during parking m aneuvers or other very low speed m aneuvers. This may be caused by a low fluid level in the power steering pump or by air in the power steering fluid due to holding the pum p at relief pressure (steering wheel held all the way in one direction) for an excessive am ount of tim e (more than 5 seconds). Check the fluid level and fill to mark. System m ust sit for 1 hour to remove the air. If the condition persists, this may be a sign of excessive pump wear and the pump should be checked; R efer to Section 3B. 2. A t or near power runout, (b rake pedal near fully depressed position) a high speed fluid noise (faucet type) may be heard. This is a norm al condition and will not be heard except in em ergency braking conditions, or with vehicle stopped and pedal pushed near fully depressed position. 3. W henever the accum ulator pressure is used, a slight hiss may be noticed. It is the sound of the hydraulic fluid escaping through the accum ulator valve, and is completely normal. LIGHT TRU CK SERVICE MANUAL 5-4 BRAKES 4. A fter the accu m u lato r has been em ptied, and the engine is started again, another hissing sound m ay be heard during the first brake application or the first steering m aneuver. This is caused by the fluid rushing through the accum ulator charging orifice. It is normal and will only be heard once after the accum ulator is emptied. However, if this sound continues, even though no apparent accum ulator pressure assist was m ade, it could be an indication th a t the accum ulator is not holding pressure and should be checked using the procedure for " A C C U M U L A T O R L E A K D O W N T E S T ". 5. A fter bleeding, a "gu lp in g " sound m ay be present during brak e ap p licatio n s as noted in the bleeding instructions. CHECKING THE RESERVE SYSTEM 1. S tart engine and charge accum ulator by applying the brake pedal or by turning the steering wheel from stop to stop. Turn off engine and let vehicle sit for one hour. A fter one hour there should be at least two power assisted applications with the engine off. 2. If the reserve system will not retain a charge for one hour, but functions norm ally im m ediately following charging, the accum ulator valves are at fault and the LIGHT TRU CK SERVICE MANUAL booster m ust be disassembled and the accum ulator valves replaced. 3. If the accum ulator can be heard charging and dis­ charging, but it does not hold a charge, disassem ble the booster and replace the accum ulator valves. 4. Deplete the accum ulator by pressing the brake pedal 4 or 5 times. If the accum ulator can has lost its gas charge, it is possible to rotate or wobble the accum ula­ tor can w ith respect to the housing. R eplace the accum ulator assembly. BOOSTER FUNCTIONAL TEST W ith the engine off", apply the brake pedal several times until the accum ulator is completely depleted. Depress the brake pedal (approxim ately 40 p o u n d s/180 N pedal force) and sta rt the engine. The pedal should fall and then push back against driver’s foot. ACCUMULATOR LEAKDOWN TEST S ta rt engine and charge accum ulator by either apply­ ing the brake pedal (approxim ately 100 pounds/450 N force) or by turning the steering wheel from stop to stop. Turn off engine and let vehicle sit for one hour. A fter one hour there should be two power assisted applies w ith engine stopped. BRAKES 5-5 HYDRO — BOOST DIAGNOSIS CONDITION Excessive Brake Pedal Effort CAUSE CORRECTION Loose or broken power steering pump belt. Tighten or replace the belt. No fluid in power steering reservoir. Fill reservoir and check for external leaks. Leaks in Hydro-Boost Replace faulty parts. Leaks at Hydro-Boost tube fittings. Tighten fittings or replace tube seats, if faulty. External leakage at accumulator Replace “0 ” ring and retainer. Faulty booster piston seal causing leakage at booster flange vent. Overhaul with new seal or input rod and piston assembly. Faulty booster input rod seal with leakage at input rod end. Overhaul with new seal kit. Faulty booster cover seal with leakage between housing and cover. Overhaul with new seal kit. Faulty booster spool plug seal. Overhaul with spool plug seal kit. Excessive seal friction in booster. Overhaul with new seal kit. Faulty spool action. Flush steering system while pumping brake pedal. Restriction in return line from booster to pump reservoir. Replace line. Damaged input rod end. Replace input rod and piston assembly. Crabby Brakes Faulty spool action caused by contamina­ tion in system. Flush steering system while pumping brake pedal. Booster Chatters Pedal Vibrates Power steering pump belt slips. Tighten belt. Low fluid level in power steering pump reservoir. Fill reservoir and check for external leaks. Faulty spool operation caused by contamin­ ation in system. Flush steering system while pumping brake pedal. Contamination in steering hydro-boost system Flush steering system while pumping brake pedal Internal leakage in accumulator system Overhaul unit using accumulator rebuild kit and seal kit. Slow Brake Pedal Return Accumulator Leak Down-System does not hold charge Fig. 5-2-Hydro-Boost Diagnosis LIGHT TRUCK SERVICE MANUAL 5-6 BRAKES CONDITION POSSIBLE CAUSE CORRECTION 1. Incorrect tire pressures. 1. Inflate evenly on both sides to the recommended pressures. 2. Front end out of line. 2. Check and align to manufacturer's specifications. 3. Unmatched tires on same axle. For radial tire lead refer to Section 3E. 3. Tires with approximately the same amount of tread should be used on the same axle. 4. Restricted brake pipes or hoses. 4. Check foe soIf hoses and damaged lines. Replace with new hoses and new double­ walled steel brake tubing. 5. Malfunctioning caliper assembly. 5. Check for stuck or sluggish pistons, proper lubrication. Remove and rebuild caliper. 6. Defective or damaged shoe and lining (grease or brake fluid on lining or bent shoe). 6. Install new shoe and lining in complete axle sets. 7. Malfunctioning rear brakes. 7. Check for inoperative auto adjusting mechanism, defective lining (grease or brake fluid on lining) or defective wheel cylinders. Repair as necessary. 8. Loose suspension parts. 8. Check and torque all suspension mountings to specifications. 9. Loose calipers. 9. Check and torque bolts to specifications. Noise (high pitched squeak without brake applied). 1. Front linings worn out. 1. Replace linings. Brake roughness or chatter (Pedal Pulsates) 1. Excessive lateral runout. 1. Check per instructions and replace or machine rotor, if not within specifications. 2. Parallelism not within specifications. 2. Check per instructions and replace or machine the rotor, if not within specifications. 3. Wheel Bearings not adjusted. 3. Adjust wheel bearings to correct specifications. 4. Rear drums out of round. 4. Check runout and, if not within specifications, turn the drums (not over maximum of 0.060 on the diameter). Pulls LIGHT TRUCK SERVICE MANUAL BRAKES 5-7 CONDITION POSSIBLE CAUSE CORRECTION Brake roughness or chatter (Pedal Pulsates) — Continued 5. Shoe reversed (steel against iron). 5. Replace shoe and lining and machine rotor within specifications. Excessive Pedal Effort 1. Malfunctioning power brake. 1. Check power brake and repair if necessary. 2. Partial system failure. 2. Check front and rear brake system and repair, if necessary. Also, check and repair brake warning light circuit if a failed system is found and light did not function. 3. Excessively worn shoe and lining. 3. Check and replace in axle sets. 4. Piston in caliper stuck or sluggish. 4. Remove caliper and rebuild. 5. Fading brakes due to incorrect lining. 5. Remove and replace with original equipment lining (or equivalent). 1. Partial brake system failure. 1. Check both front and rear system for a failure and repair. Also check and repair warning light circuit. It should have indicated a failure. 2. Insufficient fluid in master cylinder. 2. Fill reservoirs with approved brake fluid. Check for leaks. Check warning light. 3. Air trapped in system. 3. Bleed system. 4. Rear brake not adjusting. 4. Adjust rear brakes and repair auto adjusters. 5. Bent shoe and lining. 5. Replace axle set of shoe and lining. 1. Master cylinder pistons not returning correctly. 1. With reservoir cover off, check for fluid spurt at bypass holes as pedal is depressed. Adjust push rod, if necessary, or rebuild master cylinder. 2. Restricted brake pipes or hoses. 2. Check for soft hoses or damaged pipes and replace with new hoses and new double-walled steel brake tubing. Excessive Pedal Travel Dragging Brakes (A very light drag is present in all disc brakes immediately after pedal is released.) LIGHT TRUCK SERVICE MANUAL 5-8 BRAKES CONDITION POSSIBLE CAUSE CORRECTION Dragging Brakes (A very light drag i t present In all disc brakes immediately after pedal is released.) — Continued 3. Incorrect parking brake adjustment on rear brakes. 3. Check and readjust to correct specifications. 4. Incorrect installation of inboard shoe and lining. 4. Refer to caliper installation in this section. Grabbing or Uneven Braking Action 1. All conditions listed under "PULLS". 1. All corrections listed under "PULLS". 2. Malfunction of combination valve. 2. Replace and bleed system. 3. Malfunction of power brake unit. 3. Check operation and repair, if necessary. 4. Binding brake pedal mechanism. 4. Check and lubricate, if necessary. Possibly replace pedal bushing and/or spacer. 1. Uneven pad wear caused by caliper not sliding due to improper clear­ ance or dirt. 1. Remove caliper and correct as necessary. 2. Uneven rotor wear causing a thickness variation between the two braking surfaces. 2. Machine rotors as follows: a. Machine rotors to obtain a circumferential thickness variation no greater than .0005" in 360° and a lateral runout no greater than .004" (max. rate of change not exceed .001" in 30°). b. Check caliper freeness. With rotor removed, install caliper and mounting bolts (pins). Check for .005"-.012" clearance at both top and bottom of caliper. If less than .005" is found, file with a flat file until at least .005" is obtained. DO NOT EXCEED A MAXIMUM of .012" per end or .024" total clearance. Caliper clearance to inboard and outboard reaction pads must be equal within .004" both at the top and bottom of the caliper. This is to ensure correct alignment of caliper to knuckle during a brake application. c. Remove caliper after freeness check. Clean pins and sleeves, replace "O" rings, and apply a light coating of silicone grease or equivalent to all contact points and "O" rings. Pulsation (roughness) Felt during normal brake application. LIGHT TRU CK SERVICE MANUAL BRAKES \ <5- \ <0. \ <£. \ Leaking Brake Line or Connection X XX Leaking Wheel Cylinder or Piston Seal X XX Leaking Master Cylinder X XX A ir In Brake System <£. \ A \ <£\ sc \ < ^ \ A \ A \ „< £ \ XX X X X X X XX X XX X Contaminated or Improper Brake Fluid XX Leaking Vacuum System X X X X Restricted Air Passage in Power Head X XX X Damaged Power Head X X X X X Improperly Assembled Power Head Valvinq X X X X XX Worn Out Brake Lining - Replace X X X X X X X X X X X X X XX X X X Uneven Brake Lining Wear Replace and Correct X X X X X X X XX XX XX X X XX X X X X XX XX X X XX Glazed Brake Lining X Incorrect Lining Material - Replace Contaminated Brake Lining - Replace Linings Damaged by Abusive Use - Replace Excessive Brake Lining Dust Heat Spotted or Scored Brake Drums or Rotors Out-of-Round or Vibrating Brake Drums X X X X X X X X XX X XX X X X XX X XX X X X Incorrect Wheel Cylinder Sizes Faulty Metering Valve X X X X X X X X Brake Pedal Linkage Interference or Bindinq X X X X X X XX X X X X X X X X X X X X X X X X X X XX XX X ♦ X XX XX X X X XX X XX Incorrect Tire Pressure X X X Loose Front Suspension Attachments X Out-of-Balance Wheel Assemblies Faulty Proportioning Valve XX XX Incorrect Front End Alignment Improperly Adjusted Master Cylinder Push Rod Sticking Wheel Cylinder or ...Caiicai P isto n s................................... X X Drums Tapered or Threaded Operator Riding Brake Pedal X X Improperly Adjusted Parking Brake Incorrect Wheel Bearing Adjustment X X Excessive Rotor Run-Out Weak or Incorrect Brake Shoe Retention Sorinas Brake Assembly Attachments Missinq or Loose Insu fficie nt Brake Shoe Guide Lubricant Restricted Brake Fluid Passage or Stickinq Wheel Cylinder Piston X XX Out-of-Parallel Brake Rotors Faulty Automatic Adjusters 5-9 X X XX X X XX X X X X X X X X - Indicates causes X X XX X X X X X X X X X 5-10 BRAKES ON-VEHICLE SERVICE PEDAL TRAVEL A t reasonably frequent intervals, the brakes should be inspected for pedal travel, which is the distance the pedal moves tow ard th e floor from a fully-released position. Inspection should be m ade with the brake pedal firmly depressed (approxim ately 90 lbs.) while the brakes are cold. C-K -G M a n u a l......... 4.5" (115 mm) C-K -G P o w e r.......... 3.5" (90 mm) P (Except J F 9 ) ....... 3.5 " (90 m m) P ( J F 9 ) ...............6.0" (1 5 0 m m ) On power brake-equipped vehicles, pum p the pedal a minimum of 3 tim es with the engine off before m aking pedal travel checks. This exhausts all vacuum from the power booster. STOP LIGHT SWITCH Adjustment (Fig. 5-3) The design of the switch and valve m ounting provides for autom atic adjustm ent when the brake pedal is m anually returned to its m echanical stop as follows: 1. W ith brake pedal depressed, insert switch an d /o r valve assembly into tubular clip until switch body an d/or valve assembly seats on tube clip. N ote th a t audible "clicks" can be heard as threaded portion of switch and valve are pushed through the clip tow ard the brake pedal. 2. Pull brake pedal fully rearw ard against pedal stop, until audible "click" sounds can no longer be heard. Switch a n d /o r valve assem bly will be moved in tubular clip providing proper adjustm ent. 3. Release brake pedal, and then repeat Step 2 to assure th at no audible "click" sounds rem ain. LIGHT TRUCK SFRVICF MANUAL Electrical contact should be m ade when the brake pedal is depressed 1.0-1.24" (25-31 mm) (C -K m od­ els), .45-.95'1 (11-24 mm) (G -P models) from its fully released position. BLEEDING AND FLUSHING BRAKE SYSTEM Bleeding Brake Hydraulic System A bleeding operation is necessary to remove air w hen­ ever it is introduced into the hydraulic brake system. It may be necessary to bleed the hydraulic system at all four wheel cylinders if air has been introduced through low fluid level or by disconnecting b ra k e pipes at m aster cylinder. If brake pipe is disconnected at any wheel cylinder, then th a t wheel cylinder only need be bled. If pipes are disconnected at any fitting located between m aster cylinder and wheel cylinders, then all wheel cylinders served by the disconnected pipe m ust be bled. Time required to bleed the hydraulic system when the master cylinder is removed can be reduced if the master cylinder is filled with fluid and as much as as possible is expelled before the cylinder is installed on the vehicle. Manual Bleeding W ith power brakes, remove the vacuum reserve by applying the brakes several times with the engine off. BRAKES 1. Fill the m aster cylinder reservoirs with brake fluid and keep at least one-half full of fluid during the bleeding operation. 2. If the m aster cylinder is known or suspected to have air in the bore, then it m ust be bled before any wheel cylinder or caliper in the following manner: a. D isconnect th e forw ard (blind end) brak e pipe connection at the m aster cylinder. and other c o n taim in an ts from en tering the h y d rau lic system. 1. Install the correct pressure bleeding adapter to the m aster cylinder. Brake System s JB1 throught JB6 gas engine vehicles req u ire a d a p te r J-26819, extension J-2 6 8 19-30 and clam p J-2 6 8 19-25. All other systems use J-23518. R efer to Fig. 5-4, special tool illustration and brake system description chart. b. Allow brake fluid to fill the m aster cylinder bore until it begins to flow from the forw ard pipe connector port. c. C onnect the forw ard b rak e pipe to the m aster cylinder and tighten. d. Depress the brake pedal slowly one tim e and hold. Loosen the forward brake pipe connection at the m aster cylinder to purge air from the bore. Tighten the connection and then release the brake pedal slowly. W ait 15 seconds. R ep eat the sequence, including the 15 second w ait, until all air is removed from the bore. C are m ust be taken to prevent brake fluid from contacting any painted surface. 2. 3. 4. 5. e. A fter all air has been rem oved a t the forw ard connection, bleed the m aster cylinder at the rear (cowl) connection in the sam e m anner as the front in step " d " above. f. If it is known th at the calipers and wheel cylinders do not contain any air, then it will not be necessary to bleed them. 3. Individual wheel cylinder or calipers are bled only after all air is removed from m aster cylinder. a. Place a proper size box end wrench or Tool J - 2 1472 over the bleeder valve. A ttach transparent tube over valve and allow tube to be hand subm erged in brake fluid in a transparent container. Depress the brake pedal slowly one tim e and hold. Loosen the bleeder valve to purge the air from the cylinder. Tighten bleeder screw and slowly release pedal. W ait 15 seconds. R ep eat th e sequence, including the 15 second w ait u n til all air is rem oved. It m ay be necessary to repeat the sequence 10 or more times to remove all the air. JB1 thru JB6 gas engine vehicles — Rapid pumping of the brake pedal pushes the master cylinder secondary piston down the bore in a manner that makes it difficult to bleed the rear side of the system.. 4. If it is necessary to bleed all of the wheel cylinders and calipers, the following sequence should be followed: 1) R ight rear wheel cylinder; 2) L eft rear wheel cylinder; 3) R ight front caliper; 4) Left front caliper. 5. Check the brake pedal for "sponginess" and the brake warning light for indication of unbalanced pressure. Repeat entire bleeding procedure to correct either of these two conditions. Pressure Bleeding Pressure bleeding equipm ent m ust be of the diaphragm type. T h a t is, it m ust have a rubber diaphragm between the air supply and the brake fluid to prevent air, m oisture, oil 5-11 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. NOTICE: It is very im portant th at the correct m aster cylinder bleeder a d a p te r be used to avoid possible dam age to the m aster cylinder reservoir (fig. 5-4). M ake sure the pressure tank is at least 1/3 full of Suprem e # 11 brake fluid or its equivalent. The bleeder ball m ust be re-bled each tim e fluid is added. C harge the bleeder ball to between 140-170 kPa (20 and 25 psi) W hen ready to begin bleeding, connect hose to m aster cylinder bleeder adapter and open the tank valve. Disc brakes require a m anual override of the front brake m etering or com bination valve to perm it flow to the front wheels. Therefore, it will be necessary to hold the valve stem open m anually pressure bleeding. To hold the m etering valve open to bleed the front brakes, the valve stem m ust be either pushed in or pulled out. Install m etering valve actuator J-23709. Bleed the brakes in the following sequence: right rear, left front, left rear and right front. W ith the proper size wrench over the bleeder valve attach bleeder tube. The discharge end m ust hang subm erged in a clean container partially filled with brake fluid. Open the bleeder valve a t least 3 /4 turn and allow flow to continue until no air is seen in the fluid. Close the bleed valve; Be sure it seals. R epeat Steps 7-9 for the rem aining bleeder valves (see Step 6 for sequence). Check the pedal feel for "sponginess" and repeat the entire procedure if necessary. Dispose of all removed brake fluid. Remove Tool J-23709 from the com bination valve and tighten the m ounting bolt. Disconnect bleeder equipm ent from the brake bleeder adapter. Remove bleeder adapter. W ipe all areas dry if fluid was spilled during adapter removal. Fill m aster cylinder reservoir(s) to proper level and install m aster cylinder diaphragm and cover. Flushing Brake Hydraulic System It is recom m ended th a t the entire hydraulic system be thoroughly flushed with clean brake fluid whenever new parts are installed in the hydraulic system. Flushing is also recommended if there is any doubt as to the grade of fluid in the system. If fluid has been used which contains the slightest trace of m ineral oil, all rubber parts th at have been subjected to the contam inated fluid should be replaced. LIGHT TRUCK SFRVICF MANUAL 5-12 BRAKES HYDRO-BOOST BLEEDING PROCEDURE 11. Check oil level and refill as required. W henever the booster is removed and reinstalled, the steering system should be bled as outlined below. 12. If oil is extrem ely foamy, allow vehicle to stand a few m inutes w ith engine off and repeat above procedure. a. Check belt tightness and check for a bent pulley. (Pulley should not wobble w ith engine running.) b. Check to m ake sure hoses are not touching any other parts of the vehicle, particularly sheet m etal. c. Check oil level, filling to proper level if necessary, following operations 1 through 10. This step and Step " d " are extrem ely im portant as low oil level an d /o r air in the oil are the most frequent causes of objectionable pum p noises. d. Check the presence of air in the oil. A ir will show up as milky appearing oil. If air is present, attem p t to bleed system as described in operations 1 through 10. If it becomes obvious th a t the pum p will not bleed after a few trials, proceed as outlined under Power Steering System Test Procedure in the "S teerin g " section of this m anual. 1. 2. 3. 4. NOTICE: Power steering fluid and brake fluid cannot be mixed. If brake seals contact steering fluid or steering seals contact brake fluid, seal dam age will result. Fill oil reservoir to proper level and let oil rem ain undisturbed for a t least two m inutes. S tart engine and run m om entarily. Add oil, if necessary. R epeat above procedure until oil level rem ains constant after running engine. 5. Raise front end of vehicle so th a t wheels are off the ground. 6. Turn the wheels (off ground) right and left, lightly contacting the wheel stops. 7. Add oil if necessary. 8. Lower the vehicle. 9. S ta rt engine and depress the brake pedal several times while rotating the steering wheel from stop to stop. 10. T urn engine off and then pum p brake pedal 4-5 times to deplete accum ulator pressure. 13. T he presence of trapped air in the system will cause the fluid level in the pum p to rise when the engine is turned off. C ontinue to bleed system until this condition no longer occurs. BRAKES 5-13 Fig. 5-5--Front Brake Pipes and Hoses--C-K Models LIGHT TRUCK SERVICE MANUAL 5-14 BRAKES Fig. 5-6--Front Brake Pipes and Hoses--G Models Fig. 5-7--Front Brake Pipes and Hoses--P Models 5-16 BRAKES G MODELS VIEW CK MODELS CK10-20 (EXCEPT C20-43) VIEW C20 (43) CK30 VIEW CK10 P MODELS Fig. 5-8--Rear Brake Hoses LIGHT TRU CK SERVICE MANUAL VIEW BRAKES BRAKE PIPES Replacement (Figs. 5-5 thru 5-7) NOTICE: N ever use copper tubing because copper is subject to fatgue cracking and corrosion which could result in brake failure. 1. Procure the recom m ended tubing and steel fitting nuts of the correct size. (O utside diam eter of tubing is used to specify size.) 2. C ut tubing to length. C orrect length may be deter­ mined by measuring old pipe using a cord and adding 1/8 " (3 m m) for each double flare. 3. Double flare tubing ends using a suitable flaring tool such as J-23530. Follow instructions included in tool set. M ake sure fittings are installed before starting second flare. NOTICE: Double flaring tool m ust be used as single flaring tools cannot produce a flare strong enough to hold the necessary pressure. 4. Bend pipe assembly to m atch old pipe using a tubing bender. C learance of .75" (19 m m ) m ust be m ain­ tained to all moving or vibrating parts. BRAKE HOSES 5-17 Installation 1. Use new copper gaskets on both sides of fitting block, wet bolt threads with brake fluid, then with fitting orientation flange engaged with the caliper orientation ledge on JB8 and JF 9 (hose located in caliper gate on all except JB8 and JF 9 ), fasten hose to caliper; torque to specifications. 2. W ith w eight of vehicle on suspension, pass fem ale fitting through fram e or fram e bracket. Fitting fits the bracket in only one position. W ith least am ount of twist in hose, install fitting in this position. There should be no kinks in hose. 3. Install " U " clip to fem ale fitting at fram e bracket. 4. A ttach brake pipe to hose fitting using a backup wrench on fitting; torque to specifications. 5. Inspect to see th a t hose doesn’t m ake contact with any part of suspension. Check in extrem e right hand and extrem e left hand turn conditions. If hose m akes any contact, remove and correct. 6. Bleed brake system. 7. Lower vehicle from hoist. Rear Hose Removal (Fig. 5-8) 1. Raise vehicle on hoist. Inspection 2. Remove all three brake pipes from hose, two at junction T he flexible h y d rau lic b rak e hose w hich tran sm its hydraulic pressure from the steel brake pipe on the fram e to the rear axle and to the calipers should be inspected every 4 m onths or 6,000 miles (9 600 km ) (heavy duty emission vehicles), every 12 m onths or 7,500 miles (12 000 km) (light duty emission vehicles). T he brake hose assembly should be checked for road hazard dam age, for cracks and chafing of the outer cover, and for leaks and blisters. A light and m irror m ay be needed for an adequate inspection. If any of the above conditions are observed on the brake hose, it will be necessary to replace it. block and, with the use of a back-up wrench, one on the female fitting at bracket. Be careful not to bend bracket or pipes; use penetrating oil if necessary. 3. Rem ove " U " clip and tak e fem ale fitting out of bracket. 4. Observe position at which junction block is m ounted to the axle. W hen installing new hose be sure this junction block is in the sam e position. 5. Remove bolt attaching junction block to axle. Front Hose Removal (figs. 5-5 thru 5-7) 1. Raise vehicle on hoist. 2. C lean dirt and foreign m aterial from both hose end fittings. 3. Disconnect brake pipe from hose fitting using a back-up wrench on fitting. Be careful not to bend fram e bracket or brake pipe. It m ay be necessary to soak the connec­ tions with penetrating oil. 4. Remove " U " clip from fem ale fitting a t bracket and remove hose from bracket. 5. Remove bolt from caliper end of hose. Remove hose from caliper, and discard the two copper gaskets on either side of fitting block. Installation 1. Thread both rear axle pipes into junction block. 2. Bolt junction block to axle and then torque rear pipes into block. 3. Pass fem ale end of hose through bracket; fem ale fitting will fit bracket in only 1 position (except G models), 2 positions (G models). W ithout twisting hose, position female end in bracket. 4. I n s ta ll" U " clip. 5. A ttach pipe to female fitting using a back-up wrench on fitting; torque to specification, again be careful not to bend bracket or pipe. Check to see th at hose installation did not loosen fram e b racket, re-to rq u e b rack et if necessary. 6. Bleed system. 7. Lower vehicle from hoist. LIGHT TRUCK SERVICE MANUAL 5-18 BRAKES P300 (32) MODELS Fig. 5-9--Parking Brake Assembly-Typical LIGHT TRUCK SERVICE MANUAL | v ie w [a ] BRAKES 5-19 Fig. 5-10--Parking Brake System-Typical LIGHT TRUCK SERVICE MANUAL 5-20 BRAKES Fig. 5-11-Parking Brake System (Propshaft) LIGHT TRUCK SERVICE MANUAL BRAKES PARKING BRAKE PEDAL OR HANDLE Removal (Fig. 5-9) 1. Place parking brake pedal or handle in the released position. 2. Remove nuts from the engine com partm ent on C, K and G models or bolts from m ounting bracket on P models. T ake notice of th e spacers on P m odels for reinstallation. 3. Disconnect the release handle rod at the parking brake assem bly end (C-K models). 4. Remove the bolts from the underside of the dash and lower the brake assembly (C -K -G M odels). 5. C-K-G Models- Disconnect the cable ball from the parking brake clevis and remove the assembly. P Models- Remove the clevis pin and disconnect the cable from the brake assembly; remove the assembly. Installation Reverse the removal procedure. Torque all bolts and nuts. A fter installing the clevis-pin, use a new cotter pin to secure the clevis pin. A d ju st th e cable if necessary as outlined below. NOTICE: See "N o tice" on Page 1 of this section. ADJUSTMENT A djustm ent of parking brake cable is necessary when­ ever holding ability is not adequate or whenever the center brake cables have been disconnected. The service brake m ust be properly adjusted as a base for parking brake adjustm ent; conversely the parking brake m ust be properly adjusted for the service brake to function as intended. Inspection If com plete release of the parking brake is not obtained, unless it is forcibly returned to its released position, or if application effort is high, check parking brake assembly for free operation. If operation is sticky or a bind is experienced, correct as follows: 1. Clean and lubricate brake cables and equalizer with Delco Brake Lube (or equivalent). 2. Inspect brake assembly for straightness and alignm ent (replace if necessary). 3. C lean and lubricate parking brake assem bly with Delco Brake Lube (or equivalent). 4. C hecking routing of cables for kinks or binding. Adjustment—Foot Pedal Type Before adjusting parking brake, check service brake condition and adjustm ent. 1. Raise vehicle on hoist. 2. Loosen the equalizer adjusting nut. 3. Apply parking brake 4 notches from fully released position. 5-21 4. Tighten the equalizer nut until a m oderate drag is felt when the rear wheels are rotated forward. NOTICE: See "N o tic e" on Page 1 of this section. 5. Fully release parking brake and rotate the rear wheels. N o drag should be present. 6. Remove vehicle from hoist. Adjustment-Orscheln Lever Type 1. T urn adjusting knob on parking brake lever counter­ clockwise to stop. 2. Apply parking brake. 3. Raise vehicle on a hoist. 4. Loosen nut at interm ediate cable equalizer and then adjust nut to give light drag at rear wheels. NOTICE: See "N o tic e" on Page 1 of this section. 5. R eadjust parking brake lever knob to give a definite snap-over-center feel. PARKING BRAKE (PROPELLER SHAFT)INTERNAL EXPANDING Adjustment-Drum On 1. Jack up at least one rear wheel. Block wheels and release hand brake. 2. Remove cotter pin and clevis pin connecting pull rod and relay lever. This will assure freedom for full shoe release. NOTICE: It m ay be necessary to knock out lanced area in brake drum with punch and ham m er to gain entry into adjusting screw through brake drum . Be sure all m etal has been rem oved from parking brake com partm ent. 3. R otate brake drum to bring one of access holes into line w ith adju stin g screw a t bottom of shoes (m an u al transm ission), top of shoes (autom atic transm ission). 4. Expand shoes by rotating adjusting screws with screw­ driver inserted through hole in drum . Move outer end of screwdriver away from drive shaft. Continue ad ju st­ m ent until shoes are tight against drum and drum cannot be rotated by hand. Back off adjustm ent ten notches and check drum for free rotation. 5. Place parking brake lever in fully released position. Take up slack in brake linkage by pulling back on cable ju st enough to overcome spring tension. A djust clevis of pull rod or front cable to line up with hole in relay levers. a. Insert clevis pin and cotter pin, then tighten clevis locknut. b. Install a new metal hole cover in drum to prevent contam ination of brake. c. Lower rear wheels. Remove jack and wheel blocks. NOTICE: See "N o tice" on Page 1 of this section. Adjustment-Drum Off 1. W ith parking brake drum off, use special Tool J -2 1177 or J-22364, D rum to Brake Shoe Clearance G auge, to check diam eter of drum clearance surface. LIGHT TRUCK SERVICE MANUAL 5-22 BRAKES 2. Turn the tool to the opposite side and fit over brake shoes by turning the star wheel until the gauge just slides over the linings. 3. R otate the gauge around the brake shoe lining surface to insure proper clearance. 4. Install propeller shaft flange at m ainshaft as outlined in transm ission section. 5. Lower rear wheels. Remove jack and wheel blocks. 2. 3. PARKING BRAKE CABLES (Fig. 5-10) 4. Front Cable Replacement 1. Raise vehicle on hoist. 2. Remove adjusting nut from equalizer. 3. Remove retainer clip from rear portion of front cable at fram e and from lever arm . 4. Disconnect front brake cable from parking brake pedal or lever assemblies. Remove front brake cable. On some models it m ay assist installation of new cable if a heavy cord is tied to other end of cable in order to guide new cable through proper routing. 5. Install cable by reversing removal procedure. 6. A djust parking brake. Center Cable Replacement 1. Raise vehicle on hoist. 2. Remove adjusting nut from equalizer. 3. Unhook connector a t each end and disengage hooks and guides. 4. Install new cable by reversing removal procedure. 5. A djust parking brake. 6. Apply parking brake 3 tim es with heavy pressure and repeat adjustm ent. Rear Parking Brake Cable Replacement 1. 2. 3. 4. 5. 6. 7. 8. Raise vehicle on hoist. Remove rear wheel and brake drum . Loosen adjusting nut at equalizer. Disengage rear cable at connector. Bend retainer fingers. Disengage cable a t brake shoe operating lever. Install new cable by reversing removal procedure. A djust parking brake. COMBINATION VALVE Electrical Circuit Test 1. Disconnect wire from switch term inal and use a jum per to connect wire to a good ground. 2. Turn ignition key on "O n " - warning lam p should light. If lam p does not light, bulb is burned out or electrical circuit is defective. R eplace bulb or repair electrical circuit as necessary. 3. W hen w arning lamp lights, turn ignition switch off. D isconnect ju m p er and reconnect w ire to switch term inal. Warning Light Switch Test 1. Raise vehicle on hoist. A ttach a bleeder hose to a rear brake bleed screw and im m erse the other end of the LIGHT TRUCK SERVICE MANUAL 5. hose in a container partially filled with clean brake fluid. Be sure m aster cylinder reservoir is full. Turn ignition switch to "O n "; open bleeder screw while a helper applies m oderate pressure to the brake pedal; warning lamp should light. Close bleeder screw before helper releases brake pedal. Reapply brake pedal with m oderate-to-heavy pressure; light should go out. A ttach the bleeder hose to a front brake bleeder screw and repeat above test. W arning lam p action should be the same as in Step No. 2. T urn ignition switch off. If warning lamp does not light during Steps 2 and 3 but does light when a jum per is connected to ground, the warning light switch portion of the com bination valve is defective. Do not attem pt to disassem ble the com bina­ tion valve. If any portion of the com bination valve is defective, it must be replaced with a new com bination valve. Lower vehicle to floor. Check and refill m aster cylinder to proper level. Replacement The com bination valve is not repairable and m ust be serviced as a complete assembly. 1. Disconnect hydraulic lines a t com bination valve. Plug lines to prevent loss of fluid and en tran ce of dirt. Disconnect warning switch wiring harness from valve switch term inal. 2. Remove com bination valve. 3. Install com bination valve by reversing removal steps. 4. Bleed entire brake system. Do not move vehicle until a firm brake pedal is obtained. BRAKE PEDAL The brake pedal mounting is an integral design with the cluth pedal (except autom atic transm ission), necessitating the removal of the clutch pedal before removing the brake pedal. Removal (Fig. 5*12) 1. Remove the pull back spring from the body or brake pedal support bracket. 2. Manual Transmission Vehicles-- Remove the clutch pedal as outlined under "C lutch P edal" in Section 7C. Automatic Transmission Vehicles— Remove pedal pivot bolt nut or pivot pin retainer and remove bolts or pin and bushings. 3. P Models-- Remove the sleeve assembly screw a tta c h ­ m ent and remove sleeve. 4. Disengage the push rod from the m aster cylinder and remove the pedal. Inspection Clean all parts and inspect for wear, cracks or any other dam age th at m ight im pair operation; replace if required. Installation Reverse the above procedure and m ake certain the brake pedal is secure and adjusted properly before operating the vehicle. L ubricate pedal pivot bushings and pivot pin, bolt or sleeve with Delco Brake Lube (or equivalent). A djust stoplam p switch. BRAKES 5-23 NOTICE: See "N o tic e" on Page 1 of this section. BRAKE PEDAL ROD P30(32) Models Replacement (Fig. 5-13) 1. Remove the cotter pin, nut, special washers and bolt at the brake pedal lever end of rod; discard the cotter pin. 2. Remove the boot to floorpan screws. 3. Raise the vehicle on a hoist. 4. Remove the cotter pin, nut, special washers and bolt at the lower end of the rod and remove the pedal rod assembly. Discard the cotter pin. 5. To install a new rod, adjust the rod length to 31.00" (790 mm ) (center of upper attachm ent to center of lower attachm ent). 6. L ubricate the pedal rod bolts and special washers with Delco Brake Lube (or equivalent). 7. Install the rod up through the floorpan opening and install the lower pivot bolt, special washers and nut. Tighten the nut to 22-30 lb. ft. (30-40 N -m ) and install a N E W cotter pin. 8. Push the boot up to the floorpan. 9. Lower the vehicle from the hoist. 10. Install the rod upper pivot bolt, special washers and nut. Tighten the nut to 22-30 lb. ft. (30-40 N-m ) and install a N E W cotter pin. 11. Fasten the boot to the floorpan and compress the boot to 2.54" (65 mm ) installed height; tighten the boot to 2.54" (65 mm) installed height; tighten the boot screws to 13-18 lb. in. (1.5 - 2.0 N-m ). (R efer to Figure 5-13). 12. A djust brake pedal and stoplam p switch as outlined previously. LIGHT TRUCK SERVICE MANUAL 5-24 BRAKES P30(42) and G Models MASTER CYLINDER Replacement Filling Cylinder 1. G Models- Remove the brake pedal striker screw and remove the striker. Remove the cotter pin and washer and disconnect the pedal rod from the brake pedal. 2. P30(42) Models- Remove the cotter pin nut and bolt to disconnect the pedal rod from the brake pedal. 3. Remove the pedal rod retainer bolt (at the rod pivot) and remove the retainer. 4. Remove the cotter pin and washer and remove the pedal rod. 5. To install a new rod, reverse Steps 1-4 above. L ubricate pivot points with Delco Brake Lube (or equivalent). NOTICE: See "N o tic e " on Page 1 of this section. 6. Check brake pedal and stoplam p switch adjustm ents as outlined previously. The m aster cylinder m ust be kept properly filled to insure adequate reserve and to prevent air from entering the hydraulic system. However, because of expansion due to heat absorbed from brakes and from engine, m aster cylinder must not be overfilled. The brake fluid reservoir is on the m aster cylinder which is located under the hood on the left side of the dash. Thoroughly clean reservoir cover before removal to avoid getting dirt into reservoir. Remove cover and dia­ phragm . Add fluid as required to bring level to 1/4" (6 mm) (plus or minux 1/8 " - 3 mm) from the lowest portion of the top of each reservoir. Use Delco Suprem e No. 11 H ydraulic Brake Fluid or equivalent. Do not use shock absorber fluid or any other fluid which contains m ineral oil. Do not use a container which has been used for m ineral oil or a container which is wet from w ater. M ineral oil will cause swelling and distortion of rubber parts in the hydraulic brake system and w ater will mix with brake fluid, lowering the fluid boiling point. Keep all fluid contain­ ers capped to prevent w ater contam ination. Fig. 5-13--Brake Pedal and Stop Lamp Adjustment P30(32) Model LIGHT TRUCK SERVICE MANUAL BRAKES MASTER CYLINDER ASSEMBLY GENERAL DESCRIPTION This master cylinder is designed for use with a system incorporating low drag calipers. In addition to the standard master cylinder functions, a quick take-up feature is included. This provides a large volume of fluid to the wheel brakes at low pressure with initial brake application. The low pressure fluid quickly provides the displacement requirements created by the seal retracting pistons into the front calipers and spring retraction of the rear drum brake shoes. NOTICE: To prevent damage to brake parts, use all components included in repair kits. Lubricate parts with clean, fresh brake fluid. Do not use lubricated shop air on brake parts. Torque values specified are for dry, unlubricated fasteners. RESERVOIR COVER RESERVOIR D IAPH RAG M 5-25 5-26 BRAKES 1. REMOVE AND INSTALL MASTER CYLINDER. REMOVE 1. Disconnect two hydraulic lines. 2. Remove two attaching nuts. 3. Remove master cylinder as shown. 3. REMOVE AND INSTALL PRIMARY AND SECONDARY PISTONS. INSTALL REMOVE INSTALL SEE NOTICE ON PAGE 5-1 OF THIS SECTION 1. Depress primary piston and remove lock ring. SEE NOTICE ON PAGE 5-1 OF THIS SECTION. 1. Install master cylinder as shown and torque attaching nuts to 30-45 N-m (22-30 ft-lb). 2. Attach two hydraulic lines. Torque tube nuts to 13.6-20.3 N-m (120-180 in-lb). MASTER CYLINDER 2. Direct compressed air into the outlet at the blind end of the bore and plug the other outlet to remove primary and secondary pistons. 3. Disassemble secondary piston as shown in A, following. 1. Assemble secondary piston as shown in A, following. 2. Install spring and secondary piston assembly in cylinder. 3. Install primary piston, de­ press, and install lock ring. 4. Inspect master cylinder bore for corrosion. If bore is corroded, replace master cylinder. No abrasives shall be used on bore. NUTS TUBE NUTS SPRING 2. REMOVE AND INSTALL RESERVOIR COVER AND DIAPHRAGM. REMOVE INSTALL 1. Remove reservoir cover and diaphragm as shown. SEE NOTICE ON PAGE 5-1 OF THIS SECTION 2. Discard any brake fluid in reservoir. 1. Install reservoir diaphragm in reservoir cover. 3. Inspect reservoir cover and diaphragm for cuts, cracks or deformation. Replace damaged or defective parts. 2. Install assembly on reservoir. SECONDARY PISTON ASSEMBLY PRIMARY PISTON ASSEMBLY A. REMOVE INSTALL 1. Remove seals as shown. 1. Install new seals, posi­ tioning as shown. SPRING RETAINER SECONDARY PISTON SECONDARY SEAL I i p m t T P ' i n ' c r m o p r M A^UM BRAKES 4. REMOVE AND INSTALL RESERVOIR. REMOVE 1. Remove reservoir as shown in A, following. 5-27 5. REMOVE AND INSTALL RESERVOIR GROMMETS. INSTALL 1. Install reservoir as shown in B, following. REMOVE 1. Remove reservoir grommets. INSTALL 1. Lubricate new reservoir grommets with silicone brake lube. A. 2. Press grommets into master cylinder body. Make sure grommets are properly seated. REMOVE 1. Clamp master cylinder in vise as shown—do not clamp on master cylinder body—and use pry bar to remove reservoir. GROMMET PRY BAR RESERVOIR B. INSTALL 1. Lay reservoir on flat, hard surface as shown. Press on master cylinder body using rocking motion. I IflU T T P I ITK C F R \/> rf: M ANl IIAI 5-28 BRAKES 2. Manual brake only—D isconnect b rake pedal from m aster cylinder push rod. 3. Remove two nuts holding m aster cylinder to dash or power cylinder and rem ove m aster cylinder from vehicle. Be careful not to drip brake fluid on exterior paint. Disassembly (Figs. 5-14 and 5-15) 1. Clean outside of m aster cylinder thoroughly. Remove reservoir cover and diaphragm . T urn cylinder over and pum p push rod by hand to drain all brake fluid. Always discard used fluid. 2. Manual cylinder a small, pried up brake only—Pull boot aw ay from m aster to uncover push rod retainer. The retainer has depressed tab in the side. This tab m ust be to release retainer. 3. Depress piston and remove secondary piston stop bolt from bottom of front fluid reservoir (if so equipped). 4. Place m aster cylinder in a vise so th at lock ring can be removed from groove in the inside diam eter of bore. Remove lock ring and prim ary piston assembly. R e­ move secondary piston, secondary piston spring and retainer by blowing air through the outlet port. Fig. 5-14--Delco Master Cylinder-Exploded View SECONDARY ---------------- 5. Place m aster cylinder in vise, so th at outlet holes are up. Enlarge hole in tube fitting insert using a 13/64" drill. P lace a heavy w asher over o u tlet on m aster cylinder and thread a 1/4-20 x 3 /4 " screw into the insert. Tighten screw until insert is unseated. Remove insert, screw, and washer. 6. Remove prim ary seal, and secondary seal from second­ ary piston. PRIMARY SEAL SPRING AND RETAINER 7. Use clean brake fluid to clean all m etal brake parts thoroughly. A ir dry and place cleaned parts on clean paper or lint free clean cloth. Do not use anti-freeze alcohol, gasoline, kerosene, or any other cleaning fluid th at m ight contain even a trace of m ineral oil. Inspection Inspect cylinder bore for scoring or corrosion. It is best to replace a corroded cylinder. Corrosion can be identified as pits or excessive roughness. Fig. 5-15-Delco Secondary Piston - Exploded View Except Bendix Mini-Master Cylinder and Delco Quick Take-Up Master Cylinder Removal 1. Disconnect brake pipes from m aster cylinder and tape end of pipes to prevent entrance of dirt. Polish any discolored or stained area with crocus cloth by revolving cylinder on cloth supported by finger. R inse cylinder in clean b rak e fluid. S hake excess rinsing fluid from cylinder. Do not use a rag to dry cylinder, as lint from rag cannot be kept from cylinder bore surfaces. M ake certain th a t com pensating port in cylinder is clear. '■ If scratches or corroded spots are too deep to be polished satisfactorily, the cylinder should be replaced. BRAKES Assembly 1. Place brass tube fitting insert (new parts) in outlet holes so th a t it is in a position to be pressed into outlet hole. T he recom m ended m ethod of in serting tube fitting insert is to thread a spare brake line tube nut into outlet hole and turn nut down until tube fitting insert bottoms. Remove tube nut and check outlet hole for loose burrs, which m ight have been turned up when tube fitting insert was pressed down. 2. Put new secondary seal in groove in end of secondary piston (fig. 5-15). 3. Assem ble a new prim ary seal over end of secondary piston, so th at flat side of the seal seats against flange of piston (fig. 5-15). 4. Assem ble new secondary seal into groove on end of the secondary piston. 5. In order to insure correct assem bly of the prim ary assem bly, a com plete p rim ary piston assem bly is included in the repair kits. 6. C oat bore of m aster cylinder with clean brake fluid. C oat prim ary and secondary seals on secondary piston with clean brake fluid. Insert the secondary piston spring re ta in e r into secondary piston spring. Place retainer and spring over end of secondary piston, so th at retainer locates inside lip of prim ary cup. 7. Hold m aster cylinder with open end of bore down, push secondary piston into bore, so th a t spring will seat against closed end of bore. 8. Place m aster cylinder in a vise with open end of bore up. C oat prim ary and secondary seal on prim ary piston with clean brake fluid. Push prim ary piston assembly, spring end first, into bore of m aster cylinder. Hold the piston down and snap lock ring into position in groove in inside diam eter of bore. 9. Install a new reservoir diaphragm in reservoir cover where needed, and install cover on m aster cylinder. Beaded side faces m aster cylinder casting to insure positive sealing. T he bail w ire is now pushed into position to hold reservoir cover. 10. Manual brake o n ly -A ssem ble push rod through push rod retainer, if it has been disassem bled. Push retainer over end of m aster cylinder. A ssem ble new boot over push rod and press it down over the push rod retainer. Installation NOTICE: Refer to "N o tic e " on Page 1 of this section regarding fasteners referred to in Steps 1 and 2 below. 1. Manual brake only—Connect push rod to brake pedal pin and install retainer while holding m aster cylinder in place. 2. In stall m aster cylinder on dash or pow er cylinder; torque nuts to specifications. 3. Connect brake pipes to m aster cylinder. 4. Bleed hydraulic system. 5. Road test vehicle for proper brake perform ance. Bendix Mini-Master Cylinder Removal, Inspection and Installation procedures are the same as described for "E xcept Bendix M ini-M aster C ylinder". 5-29 Disassembly 1. Remove the reservoir cover and diaphragm , and drain the fluid from the reservoir. 2. Remove the four bolts th a t secure the body to the reservoir using Socket J-25085. 3. Remove the small " O " ring and the two com pensating valve seals from the recessed areas on the bottom side of the reservoir. Do not remove the two small filters from the inside of the reservoir unless they are dam aged and are to be replaced. 4. Depress the prim ary piston using a tool with a smooth rounded end. Then remove the com pensating valve poppets and the com pensating valve springs from the com pensating valve ports in the m aster cylinder body. 5. Using a small screwdriver, remove the snap ring at the end of the m aster cylinder bore. Then release the piston and remove the prim ary and secondary piston assem ­ blies from the cylinder bore. It may be necessary to plug the front outlet port and to apply low air pressure to the front com pensating valve port to remove the secondary piston assembly. Assembly 1. L u b ricate th e secondary piston assem bly and the m aster cylinder bore with clean brake fluid. 2. Assemble the secondary spring (shorter of the two springs) in the open end of the secondary piston actuator, and assem ble the piston return spring (longer spring) on the projection at the rear of the secondary piston. 3. Insert the secondary piston assembly, actuator end first, into the m aster cylinder bore, and press assembly to the bottom of the bore. 4. L u b ric ate th e prim ary piston assem bly w ith clean brake fluid. Insert the prim ary piston assembly, ac tu a ­ tor end first, into the bore. 5. Place the snap ring over a smooth round ended tool and depress the pistons in the bore. 6. A ssem ble the retain in g ring in th e groove in the cylinder bore. 7. Assemble the com pensating valve seals and the small " O " ring seal in the recesses on the bottom of the reservoir. Be sure th at all seals are fully seated. 8. W hile holding the pistons depressed, assem ble the com pensating valve springs and the com pensating valve poppets in the com pensating valve ports. 9. Holding the pistons compressed, position the reservoir on the m aster cylinder body and secure with the four m ounting bolts. Tighten the bolts to 12-15 lb. ft. (16-20 N -m ). DELCO DISC BRAKE SHOE AND LINING Lining Inspection Inspect the brake linings per m aintenance schedule and anytim e th at the wheels are removed (tire rotation, etc.) Check both ends of the outer shoe by looking in a t each end of the caliper (see figure 5-18). Check the lining thickness on the inner shoe by looking down through the inspection hole in the top of the caliper housing. W henever the lining is LIGHT TRUCK SERVICE MANUAL 5-30 BRAKES COVER DIAPHRAGM FILTER RESERVOIR COMPENSATING VALVE VALVE SEAL POPPET SPRING SECONDARY SPRING SECONDARY PISTON PISTON RETURN PRIMARY SNAP SPRING PISTON RING Fig. 5-16--Bendix Mini-Master Cylinder-Exploded View worn to the approxim ate thickness of the shoe, the shoe and lining should be removed. A fter removal, m easure the lining thickness. The shoe and lining should be replaced at any tim e when the lining is worn to within 1/32" (0.80 mm) of a rivet or 1/32" (0.80 m m ) of the shoe at any point or when wear indicator contacts the rotor. Always replace linings in sets (both right and left front). All front disc brakes have a wear indicator th a t makes a noise when the linings w ear to a degree where replacem ent is required, (fig. 5-19). The spring clip is an integral part of the inboard shoe and lining. W hen the lining is worn, the clip contacts the rotor and produces a w arning noise. C heck flatness o f b rak e pads. P lace inboard and outboard pad surfaces together and check for gap between pad surfaces. If more th an 0.13mm (.005 ") gap is m easured at m iddle of pad (m idw ay between attaching lugs), pad m ust not be used. This applies to new or used brake pads. W henever the front disc brakes are relined, the rear brakes should also be checked. Caliper Removal NOTICE: See "N o tice" on Page 5-1 of this section. 1. Remove two thirds of the total fluid capacity from the front m aster cylinder reservoir. Removal of the fluid is LIGHT TRUCK SERVICE MANUAL necessary to prevent reservoir overflow when the caliper piston is pushed back in its bore to remove the caliper. This m ay be done by breaking the front line connection at the m aster cylinder and bleeding down the fluid level. Do not remove the brake line or completely empty th e reservoir or it will be necessary to bleed the hydraulic system. D iscard - do not attem pt to reuse the brake fluid removed. 2. Raise the vehicle on a hoist and remove the wheel covers and wheel assemblies. Position a 7 inch " C " clam p on the caliper so th a t solid side of the clam p rests against the m etal part of the outboard shoe (fig. 5-20). Tighten the " C " clam p until the caliper moves away from the vehicle far enough to push the piston to the bottom of the piston bore. This will allow the shoes to back off from the rotor surfaces. Remove the " C " clamp. 3. It is not necessary to disconnect the brake hose for shoe and lining replacem ent. Remove the two mounting bolts which attach the caliper to the support bracket (fig. 5-21). Lift the caliper off the rotor and remove the inboard shoe. Dislodge the outboard shoe and position the caliper on the front suspension arm so th a t the brake hose will not support the weight of the caliper. BRAKES 5-31 Cleaning and Inspection Remove the shoe support spring from the cavity in the piston. 4. U sing Tool J-22835, rem ove th e sleeves from the inboard ears of the caliper (fig. 5-22). N ext, remove the rubber bushings from the grooves in each of the four caliper ears. 1. Thoroughly clean the holes and the bushing grooves in the caliper ears. W ipe all dirt from the m ounting bolts. Do not use abrasives on the bolts since this will dam age the plating. If the bolts are corroded, or dam aged, they should be replaced. 2. Exam ine the inside of the caliper for evidence of fluid leakage. If leakage is noted, the caliper should be overhauled. W ipe th e inside of the calip er clean, including the exterior of the dust boot. Check the boot LIGHT TRUCK SERVICE MANUAL 5-32 BRAKES Fig. 5-21--Removing Mounting Bolts Fig. 5-22--Removing Sleeves for cuts, cracks or other dam age. M ake sure th at the boot is properly, engaged in the groove in the piston and also in the caliper counter-bore (fig. 5-24). NOTICE: Do not use compressed air to clean the inside of the caliper since this m ay cause the dust boot to become unseated. 3. If the vehicle has a brake problem and diagnosis points to the rotor, it should be inspected and checked for runout at this time. Caliper Installation 1. Install rubber bushings in all four caliper ears. NOTICE: It is essential th a t the new sleeves and rubber bushings be used in order to insure the proper function­ ing of the sliding caliper design. 2. Use Tool, J-22835, to install the sleeves (fig. 5-25). Position the sleeves so th a t the end toward the shoe and lining assemblies is flush with the machined surface of the ear. LIGHT TRUCK SERVICE MANUAL 3. Install the shoe support spring by replacing the single tang end of the spring over the notch in the center of the edge of the shoe. Then press the two tangs a t the spring end of the inboard shoe spring over the bottom edge of the shoe so th at they engage the shoe securely, as shown in Figure 5-26. BRAKES 5-33 Fig. 5-28--lnstalling Outboard Shoe spring end of the inboard shoe support spring should be resting on the I.D. of the piston. NOTICE: On inboard shoes there is a specific left hand and right hand shoe. W hen properly installed the wear sensor will be tow ard rear of caliper. 5. Position the outboard shoe in the caliper, with the ears a t the top of the shoe over the caliper ears and the tab at the bottom of the shoe engaged in the caliper cut-out (see fig. 5-28). Be sure to note right and left brake shoes. 6. Postion the caliper over the rotor, lining up the holes in the caliper ears with the holes in the m ounting bracket. NOTICE: W hen reinstalling caliper be sure you haven’t turned it over, end over end. This would cause a severe twist in the brake hose. A fter positioning caliper on disc, observe brake hose being sure it is not twisted. Fig.5-27--lnstalling Inboard Shoe 4. Position the inboard shoe and lining assembly (with spring attached) in the caliper so th a t the ear end of the shoe and lining is down and the bottom end up at an angle with the spring resting on the piston I.D. (fig. 5-27). Press down on both ends of the shoe until the shoe is in a flat position, resting on the piston. The Fig. 5 -2 9 —Installing M ounting Bolts LIG H T T R U C K SERVICE M AN U AL 5-34 BRAKES 10, A fter clinching, ears are to be flat ag ain st caliper housing with no radial clearance. 11. If radial clearance exists, repeat clinching procedure. Completion 1. Replace the shoe and linings on the other front wheel disc brake in exactly the sam e m anner as just de­ scribed. Relining is to be done in full axle sets only. W hen completed, reinstall the wheel and tire assem ­ blies. Torque wheel nuts to specifications. Install wheel covers and lower the vehicle to the floor. NOTICE: See "N o tice" on Page 1 of this section. 2. W henever the front wheel disc brakes are relined, the rear drum brakes should be checked also. BENDIX DISC BRAKE SHOE AND LINING S ta rt th e bolts th ro u g h th e sleeves in th e inboard caliper ears and through the mounting bracket, making sure th a t the ends of the bolts pass under the retaining ears on the inboard shoe (fig. 5-29). Push bolts on through to engage the holes in the outboard shoes and the outboard caliper ears at the sam e tim e, threading the bolts into the m ounting bracket. Torque the bolts to 35 lb. ft. (50 N-m ). NOTICE: See "N o tic e " on Page 1 of this section. 7. A dd fresh approved brake fluid to the m aster cylinder reservoirs to bring the level up to within 1 /8 " (3 mm) of the top. 8. Pump brake pedal to seat linings against rotor. 9. C linch u pper ears o f o u tb o ard shoe by positioning channel lock pliers with one jaw on top of upper ear and one jaw in notch on bottom of shoe opposite upper ear (fig. 5-30). L IG H T T R U C K SE RV IC E M AN U AL The brake linings should be inspected any tim e the wheels are removed. Check both ends of the outboard shoe by looking in at each end of the caliper (fig. 5-31). This is the point at which the highest rate of w ear normally occurs. A t the same time, check the lining thickness on the inboard shoe by looking down through the inspection hole in the top of the caliper; see "B ra k e In sp ectio n " portion of this section. The inboard shoe is installed with the ends of the shoe resting in the steering knuckle. The large tab at the bottom of the outboard shoe is bent over at the right angle and fits in the cutout in the outboard section of the caliper. Removal (Front or Rear) NOTICE: See "N o tic e" on page 1 of this section. 1. Remove m aster cylinder cover and observe brake fuuid level in front reservoir is m ore than 1/3 full, siphon the necessary am ount out to bring the level to 1/3 full. This step is taken to avoid reservoir overflow w hen the caliper piston is pushed back into its bore. D iscard the brake fluid removed. N ever reuse brake fluid. 2. Raise the vehicle on a hoist and remove wheels. 3. Push the piston back into its bore. This can be accom ­ plished by using a "C " clam p as shown in Figure 5-33. 4. Remove the bolt at the caliper support key. Using a brass punch, remove the key and spring (fig. 5-34). 5. Lift the caliper off the disc and support in a raised position with a heavy wire (fig. 5-35). BRAKES 5-35 Clamp 2. W ipe the inside of the caliper clean, including the exterior of the dust boot. Check the boot for cuts, cracks or other dam age. NOTICE: Do not use compressed air to clean the inside of the caliper since this m ay cause the dust boot to become unseated. 3. Use a wire brush to remove any rust or corrosion from the m achined surfaces of the steering knuckle (or support) and caliper. It is im portant to clean those areas of the caliper and support th at are in contact during the sliding action of the caliper. Installation If original disc pads are being reinstalled, they m ust be installed in original positions (as m arked at removal). 1. Lubricate the caliper and steering knuckle (or support) sliding surfaces and the support spring with Delco Silicone Lube (or equivalent). NOTICE: Do not support the weight of the caliper on the brake hose as dam age to the brake hose could result. 6. Remove the inboard shoe from the steering knuckle or rear caliper support (fig. 5-32). Remove and discard the inboard shoe clip. Remove the outboard shoe from the caliper. It may be necessary to tap the shoe to loosen it in the caliper housing. M ark disc pad positions if pads are to be reinstalled. Cleaning and Inspection The shoes should be replaced when the lining is worn to approxim ately 1 /3 2 " (0.80 m m) thickness over the rivet heads. Replace shoes in axle sets. 1. Exam ine the inside of the caliper for evidence of fluid leakage. If leakage is noted, the caliper should be overhauled. 2. Install a N E W inboard shoe clip in the steering knuckle or re ar support. Be sure the tabs are positioned correctly and the loop-type spring positioned aw ay from the rotor. Install the lower end of the inboard shoe into the groove provided in the steering knuckle or support (against the spring clip). Slide the upper end of the shoe into position. Be sure the clip rem ains in position. 3. Postion the outboard shoe in the caliper with the ears at the top of the shoe over the caliper ears and the tab at the bottom of the shoe engaged in the caliper cutout. If assembly is difficult, a "C " clam p may be used. Be careful not to m ar the lining. 4. W ith both shoes installed, lift up the caliper and rest the bottom edge of the outboard lining on the outer edge of the brake disc to m ake sure th ere is no clearance between the tab at the bottom of the out­ board shoe and the caliper abutm ent. T he outboard LIG H T T R U C K SERVICE M A N U A L 5-36 BRAKES shoe should fit tightly in the caliper and should not rattle. 5. Position the caliper over the brake disc, guiding the upper caliper groove onto the m ating surface of the steering knuckel or caliper support. Position the caliper to the lower steerin g knuckle (or su p p o rt) sliding surface. NOTICE: M ake sure th a t the brake hose is not twisted or kinked since dam age to the brake hose could result. 6. Place the spring over the caliper support key, install the assembly between the steering knuckle (or rear sup­ port) and lower caliper groove. T ap into place (until the key retaining screw can be installed) using a brass punch and a light ham m er (fig. 5-36). 7. Install the screw and torque to 12 to 18 lb. ft. (18-24 N -m ). The bolt boss m ust fit fully into the circular cutout in the key. NOTICE: See "N o tic e " on Page 1 of this section. 8. Reinstall the front wheel and tire assembly. 9. A dd brake fluid to the m aster cylinder reservoir to bring the fluid level up to within 1 /4 " (6 m m ) of the top. NOTICE: Before moving the vehicle, pum p the brake pedal several tim es to m ake sure th at it is firm. Do not move vehicle until a firm pedal is obtained. Check m aster cylinder fluid level again after pum ping the brake pedal. CALIPER OVERHAUL Delco Removal 1. Removal of the caliper for overhaul is the same as for shoe and lining rep lacem en t except th a t it will be necessary to disconnect the brake hose; (R efer to front brake hose replacem ent). 2. First, disconnect the hose from the steel brake pipe and cap the fittings to prevent dirt from entering the pipe or the hose. Then, remove the U -shaped retainer from the hose fitting. W ithdraw the hose from the fram e support Fig. 5-37--Removing Piston bracket and remove the caliper - with hose attached — to a work bench for overhaul. Disassembly 1. Before beginning disassembly, thoroughly clean the exterior of the caliper using brake cleaner. Place the caliper on a clean work surface. 2. Remove the brake hose from the caliper, discarding the copper gasket. Check the hose for worn spots, cracks or other signs of deterioration, discard the hose, if dam ­ aged, to be replaced with a new hose a t reassembly. D rain brake fluid from the caliper. 3. Use clean shop towels to pad the interior of the caliper. Remove the piston by directing compressed air into the caliper inlet hole (fig. 5-37). CAUTION:Do not place the fingers in front of the piston in an attempt to catch or protect it when applying compressed air. This could result in serious injury. NOTICE: Use just enough air pressure to ease the piston out of the bore. If the piston is blown out, even with padding provided, it m ay become dam aged. 4. Use a screwdriver to pry the boot out of the caliper. Extend the screwdriver across the caliper bore, under the boot, and pry up. Be careful not to scratch the caliper bore. 5. Use a piece of wood or plastic - a plastic toothpick is ideal - to remove the piston seal from its groove in the caliper bore. DO N O T U S E A M E T A L T O O L O F A N Y T Y P E FO R T H IS O P E R A T IO N . 6. Remove the bleeder valve from the cliper. Cleaning and Inspection 1. The boot, piston seal, rubber bushings and sleeves are to be replaced each tim e the caliper is overhauled. Discard, do not bother to clean and inspect, these parts. 2. Clean all other parts in clean denatured alcohol or brake cleaner. Use dry, filtered compressed air to dry parts and blow out all passages in the caliper and bleeder valves. The use of lubricated shop air will leave a film of m ineral oil on th e m etal p arts. T his m ay dam age BRAKES ru b b er p arts w hen they com e in co n tact a fte r reassembly. 3. C heck the m ounting for corrosion, breaks in the plating or other dam age. Do not use abrasives in an attem pt to clean the pins -- replace them. 4. C arefu lly exam ine th e piston outside d iam eter for scoring, nicks, corrosion and worn or dam aged chrom e plating. If any surface defects are detected, replace the piston. 5. Check the bore in the caliper for the sam e defects as the piston with the exception of plating dam age. The piston bore is not plated and stains or minor corrosion can be polished with crocus cloth. Do not use em ery cloth. Thoroughly clean the caliper after the use of crocus cloth. If the bore cannot be cleaned up in this m anner, replace the caliper. Reassembly 5-37 3. Install the brake hose in the caliper inlet using a new copper gasket. Installation 1. Installation of the caliper and m ounting parts (rubber bushing, sleeves, shoe and lining assemblies and pins) is the sam e as for lining replacem ent except for the following: a. The brake hose m ust be connected to the brake pipe a t the fram e or fram e bracket. Use extrem e care to orient the hose so th at the keyed hose end fitting aligns with the slot in the bracket without twisting or kinking the hose. b. A fter overhaul -- or any tim e that the brake hose or line is disconnected -- the calipers m ust be bled. Bendix Removal 1. L ubricate the bore in the caliper and the new piston seal with clean brake fluid. Position the seal in the caliper bore groove. L ubricate the piston with clean brake fluid and assemble a new boot into the groove in the piston so th at the fold faces the open end of the piston. Insert the piston into the caliper bore, using care not to unseat the seal and force down to the bottom in the bore. This will require a force of 50 to 100 pounds (220 to 440 N ). Position the outside diam eter of the boot in the caliper counterbore and seat with Tool J-22904 (fig. 5-38). C lean d irt from hose to caliper connection before proceeding with removal. 1. Remove the hose to caliper bolt and cap or tape the open connections to prevent dirt from entering the hose or caliper. D iscard the copper gaskets. 2. Remove the caliper assembly as described under "Shoe and L inings-R em oval". CALIPER PISTON BOOT 2. C heck th e boot in stallatio n to m ake sure th a t the retaining ring molded into the boot is not bent and th at the boot is installed fully, below the caliper face, and evenly all around. O therw ise d irt or m oisture m ay enter the bore and cause dam age or corrosion. SQUARE RING SEAL SCREW SUPPORT KEY INBOARD SHOE CALIPER SPRING OUTBOARD SHOE ANfl-RATTLE SPRING Fig. 5-39-Bendix Brake Caliper Assembly BOOT INSTALLER (EXCEPT JB7) J -2 2 9 0 4 (JB7) J -2 8 7 3 5 DUST BOOT Fig. 5-38--Seating Boot Fig. 5-40--Rem oving the C aliper Piston L IG H T T R U C K SERVICE M AN U AL 5-38 BRAKES Disassembly (Fig. 5-39) 1. Clean the exterior of the caliper using clean brake fluid and place on a clean work surface. 2. D rain the brake fluid from the caliper. CAUTION:Do not place the fingers in front of the piston in an attempt to catch or protect it when applying compressed air. 3. Using clean shop cloths, pad the interior of the caliper and remove the piston by directing compressed air into the caliper inlet hole (fig. 5-40). Inner lip of boot must be fully seated in caliper housing. NOTICE: Use ju st enough air pressure to ease the piston out of the bore. Do not blow piston out of the bore as dam age to the piston could result. If the piston is seized or cocked or does not come out readily, release the air pressure and use a soft (brass) ham m er to rap sharply on and aro u n d the end of th e piston. R eapply air pressure to remove the piston. An altern ate m ethod of removing the piston is to stroke the brake pedal (gently) while the hydraulic lines are still connected. This will push the piston out of the caliper bore. J-24548 PISTON Fig. 5-41--Installing Caliper Piston Boot 4. Remove the boot from the piston bore. 5. Using a sm all piece of wood or plastic, remove the square ring seal from the piston bore. NOTICE: Do not use a m etal tool of any kind for this operation as it m ay dam age the bore. 6. Remove the bleeder valve from the caliper. Cleaning and Inspection T he dust boot and piston seal are to be replaced whenever the caliper is overhauled. D iscard these parts. 1. Clean all parts (other than those m entioned above in clean brake fluid. Use dry, filtered, com pressor air to blow out all passages in the caliper and bleeder valve. NOTICE: T he use of lubricated shop air will leave a film of m ineral oil on the m etal parts. This m ay dam age ru b b e r p arts w hen they come in co n tact a fte r reassembly. 2. C heck th e sliding su rfaces of the caliper, steering knuckle (or rear support) and support spring for rust or corrosion. C lean up any surface defects with crocus cloth. 3. C arefully exam ine the outside surface of the piston for scoring, nicks, corrosion and worn or dam aged plating. If any surface defects are detected, replace the piston. NOTICE: The piston outside diam eter is the prim ary sealing surface in the caliper assembly. It is m anufac­ tured and plated to close tolerances. Refinishing by any means or the use of any abrasive is not acceptable practice. 4. Check the bore in th e caliper for the same defects as the piston. The piston bore, however, is not plated and stains or minor corrosion can be polished with crocus cloth. Do not use emery cloth or any other form of abrasive. Thoroughly clean the caliper after the use of crocus cloth. If the bore cannot be cleaned up in this m anner, replace the caliper. L IG H T T R U C K SERVIC E M AN U AL Assembly 1. Lubricate the caliper piston bore and the N E W piston seal with the clean brake fluid. Position the square ring seal in the caliper bore groove. 2. L ubricate both sealing lips of the dust boot and the piston with a light film of clean brake fluid. Place the new boot over Piston Installer Tool J-24548. This is most easily accomplished by placing the boot large diam eter over the tool first, then riding the sm aller diam eter onto the tool. T he large diam eter lip must then be slid off the tool to m ake ready for installation into the bore groove. Install the boot (large bead) into th e piston bore groove by reaching inside of Tool J-24548 and pressing the boot bead into the groove (fig. 5-41). Be sure boot is fully seated in the groove before proceeding. 3. Place the piston inside of Tool J-24548, force the piston halfway into the piston bore using a wood ham m er BRAKES handle or " C " clam p (fig. 5-42); remove Tool J-24548. Check to be sure the boot was not unseated at piston installation. M ake sure the outer bead of the boot is seated in the piston outer groove.1 Installation Installation of the caliper and m ounting parts is the sam e for: "Shoe and Lining-Disc B rake" except for steps given below: 1. C onnect the brake hose to the caliper using N E W copper gaskets. NOTICE: Hose m ust be properly positioned to prevent hose twist or m isalignm ent or hose dam age m ay result. 2. Bleed the caliper assemblies as outlined earlier in this section. ROTOR SERVICING Lateral Runout 1. L ateral runout is the movement of the rotor from side to side as it rotates on the steering knuckle spindle. This could be described as " rotor wobble ". 2. The movement of the rotor from side to side in the lateral plane causes the brake shoe and lining and pistons to be knocked back into their bores. This results in additional pedal travel required and a vibration during the braking action. 3. To check lateral runout, first tighten the wheel bearings until all of the play is out of the bearings. Fasten a dial indicator to some portion of the suspension so th a t the point of the stylus contacts the rotor face approx­ im ately 1" (25 mm) from the rotor edge (fig. 5-43). Set the dial at zero. Move the rotor one complete rotation, checking the indicator as the rotor moves. 4. L ateral runout should not be over .004" (0.10 mm) total indicator reading. 5-39 of the rotor. All m easurem ents m ust be made at the same distance in from the edge of the rotor. 2. A rotor th at varies over .0005" (0.013 mm) causes pedal vibration, as well as front end vibration during brake applications. A rotor th at does not meet these specifications m ay be refinished to specifications if precision equipm ent is available. Tolerance and Surface Finish In m anufacturing the brake rotor, tolerances of the rubbing surfaces for flatness, for parallelism and for lateral runout are held very closely. The m aintenance of these close controls on the shape of the rubbing surfaces is necessary to prevent brake roughness. In addition to these tolerences, the surface finish must be held to a specified range. The control of the rubbing surface finish is necessary to avoid pulls and e rratic perform ance and to extend lining life. Light scoring of the rotor surfaces not exceeding .015" (0.38 mm) in depth, which may result from norm al use, is not detrim ental to brake operation. Machining Since accurate control of the rotor tolerances is neces­ sary for proper perform ance of the disc brakes, m achining of the rotor should be done only with precision equipm ent. All brake rotors have a minimum thickness dimension cast into them. This dimension is the minimum wear dimension and not a refinish dimension. Do not use a brake rotor that will not meet the specifications, as shown below, after refinishing. Replace with a new brake rotor. ROTOR THICKNESS REPLACEMENT (DISCARD) MINIMUM AFTER REFINISHING 1.480 1.230 .980 Parallelism 1. Parallelism is the m easurem ent of the thickness of the rotor at four or more points around the circum ference 1.465 1.215 .965 Wheel Bolt Replacement (Disc Brakes) NOTICE: See "N o tice" on page 1 of this section. 1. Remove hub and rotor assembly from vehicle. 2. M ark rotor to hub location and remove bolts attaching hub to rotor. 3. The wheel bolts on disc brakes can be pressed out from the outside of the hub and installed from inside the rotor by pressing into place. N o drilling or cutting is required. 4. Reinstall assembly and adjust wheel bearings. DRUM BRAKE SHOE AND LINING Service Brake Adjustment 1. Using a punch, knock out lanced area in brake drum . If this is done with the drum installed on the vehicle, the LIG H T T R U C K SERVICE M AN U AL 5-40 BRAKES WHEEL CYLINDER SCREWS- WHEEL CYLINDER LINKS BACKING PLATE SECONDARY SHOE & LIN IN ~ SHOE GUIDE PARKING BRAKE STRUT STRUT SPRING ADJUSTER LEVER A CTUA TING LINK HOLD DO W N PINS PARKING BRAKE LEVER WHEEL CYLINDER PRIMARY SHOE A N D LINING HOLD DO W N SPRING ADJUSTING SCREW SPRING SPRING & CUP -A D JU S T IN G SCREW BRAKE SHOE RETURN SPRING ____ R RETURN SPRINGS Fig. 5-44--Typical Drum Brake Assembly drum m ust be removed and all m etal cleaned out of the brake com partm ent. Be sure to procure a new metal hole cover and install it in the drum after adjustm ent to prevent dirt and w ater from getting into the brakes. U se J-6 1 66 to tu rn b rak e ad ju stin g screw; expand brake shoes at each wheel until the wheel can just be turned by hand. The d rag should be equal at all wheels. 2. Back off b rak e ad ju stin g screw a t each wheel 30 notches. If shoes still drag lightly on drum , back off adjusting screw one or two additional notches. Brakes should be free of drag when screw has been backed off approxim ately 12 notches. Heavy drag at this point indicates tight parking brake cables. 3. Install m etal adjusting hole cover in brake drum . 4. Check parking brake adjustm ent. Removal and Inspecting NOTICE: See "N o tice" on Page 1 of this section. 1. Raise vehicle on hoist. Remove wheel and brake drum . It m ay be necessary to back off the brake shoe adjust­ m ent before the brake drum s can be removed. To back off shoe ad ju stm en t, ro ta te shoe ad ju stin g screw downward. On JB 6, JB7 and JB8 equipped vehicles, it is necessary to remove the axle shafts to remove the hub and drum assembly; refer to Section 4B of this m anual. 2. U nhook the prim ary and secondary shoe return springs using large pliers. 3. Remove shoe hold down springs. LIG H T TR U C K SE R V IC E M AN U AL 4. Lift up on actuator, unhook actuating link from anchor pin, then remove. 5. Spread shoes to clear wheel cylinder connecting links, rem ove parking brake s tru t and spring, disconnect cable from parking brake lever, remove shoes from the backing plate. 6. S eparate the brake shoes by removing adjusting-screw and lock spring. Rem ove parking b rake lever and secondary brake shoe. 7. Clean all dirt out of brake drum . Inspect drum s and replace or recondition if required. 8. Clean all dirt from brake assemblies and inspect for any unusual condition. 9. W heel cylinders having torn, cut, or heat-cracked boots should be completely overhauled. Inspection for leakage m ay be accomplished at the boot center hole after removal of link pin. Fluid coatings on piston within cylinder and on end of link pin removed from boot are norm al, as cylinder contains a porous P IS T O N W H IC H IS IM P R E G N A T E D W IT H A C O R R O S IO N IN H IB IT IN G FL U ID . Fluid spilling from boot center hole, a fte r link pin is rem oved, indicates cup leakage and necessity for com pletely over-hauling cylinder. io. Inspect backing plate for oil leakage past wheel bearing oil seals. Correct any leak by installation of new seals (See Section 4B). BRAKES 11. Check all backing plate attaching bolts to m ake sure they are tight. Using fine em ery cloth, clean all rust and dirt from shoe contact surfaces on plate. Installation and Adjustment 1. L ubricate fulcrum end of parking brake lever with Delco Brake L ubricant or equivalent, then attach lever to secondary shoe. M ake sure th a t lever is free moving. 2. Connect brake shoes together with adjusting screw spring, then place adjusting screw in position. W hen in stallin g th e adju stin g screw spring and adjusting screw, m ake sure the spring does not touch the starwheel portion of the adjusting screw; and, also, when installing adjusting screw, m ake sure right hand thread adjusting screw is on left side of vehicle and left hand thread adjusting screw is on right side of vehicle. M ake certain starw heel lines up w ith ad ju stin g hole in backing plate. 3. L ubricate shoe contact surfaces on backing plate with a thin coating of Delco Brake L ubricant or equivalent. 5-41 S paringly apply sam e lu b ric an t w here brake cable contacts backing plate. 4. Place brake shoes on backing plate, at the same tim e engaging shoes with wheel cylinder links. The prim ary shoe (short lining) goes tow ard front of vehicle. Connect cable to parking brake lever and install strut and spring between lever and prim ary shoe. 5. Install acutator, actuator return spring and actuating link. If old brake shoe re tu rn springs are nicked, distorted or of doubtful strength (discolored from heat), it is advisable to install new parts. 6. Install shoe hold down springs. 7. Install the prim ary and secondary shoe return springs using large pliers. Be careful not to distort springs. 8. M easure brake drum I.D. using inside caliper portion of Tool J-21177 (fig. 5-45). A djust brake shoes to dimension obtained on outside caliper portion of Tool J-21177 (fig. 5-46). 9. Install brake drum s and wheels. 10. If any h y draulic connections were distu rb ed , bleed hydraulic system. 11. A djust parking brake. 12. Inspect all brake pipes, hoses and connections for evidence of fluid leakage. Tighten any leaking connec­ tion. Then apply heavy pedal pressure to brake pedal and recheck connections. 13. Check fluid level in m aster cylinder and add fluid if necessary. 14. C heck brake pedal for proper feel and for proper return. 15. Remove vehicle from hoist and road test for proper brake action. Brakes m ust not be severely applied im m ediately after installation of new brake shoes or linings. Severe application may perm anently dam age new linings and m ay score brake drums. W hen linings are new, they m ust be given m oderate use for several hundred miles of burnishing. Repair Brake Lining This procedure is to be used when brake action is unequal, severe, hard, noisy or otherwise unsatisfactory and when brake linings have had little wear. 1. C heck fluid in m aster cylinder and add fluid if necessary. 2. C heck brake pedal for proper feel and for proper return. 3. Raise vehicle on hoist and remove all wheels. 4. Remove all brake drum s. B R A K E PED A L M U ST N O T BE O P E R A T E D W H IL E D R U M S A R E R EM O V ED . NOTICE: See "N o tice" on page 1 of this section. 5. Clean all dirt out of brake drum s. Inspect drum s and replace or recondition if required. 6. C lean all d irt from brake assem blies, then inspect brake linings for uneven wear, oil soaking, loose rivets or imbedded foreign particles. If linings are oil soaked, replacem ent is required. 7. If linings are otherwise serviceable, tighten or replace loose rivets and thoroughly clean all steel or other LIG H T T R U C K SERVICE M AN U AL 5-42 8. 9. 10. 11. BRAKES im bedded particles from surfaces and rivet counter­ bores of linings. Check all backing plate bolts to m ake sure they are tight. (R efer to Section 4B for wheel stud replacem ent procedure.) M easure brake drum I.D. using inside caliper portion of Tool J - 2 1 177. A d ju st brak e shoes to dim ension obtained on outside caliper portion of Tool J-2 1 177 (figs. 5-45 and 5-46). Install drum and wheel and tire assemblies. Remove vehicle from hoist and road test for proper b rak e action. B rakes m ust not be severely applied im m ediately after installation. Severe application may perm anently dam age new linings and may score brake drum s. W hen linings are new, they m ust be given m oderate use for several hundred miles of burnishing. Propeller Shaft Brake Removal (Fig. 5-47) 1. Remove the propeller shaft; see Section 4A. 2. Remove the brake drum . It may be necessary to back off the shoe adjustm ent before removing the drum . On autom atic transm ission models, the exhaust cross­ over pipe m ay be in the way. If so, loosen the transm is­ sion rear m ounting bolts and jack the transmission sufficiently for brake drum to clear the pipe. 3. Remove the two pull back springs. 4. Remove the guide plate from anchor pin. 5. Remove shoe hold down cups, springs, and washers from hold down p ins-rem ove pins. 6. Pull brake shoe and lining assem blies aw ay from anchor pin and remove the stru t and spring. 7. Lift the brake shoes and linings with the adjusting nut and bolt and connecting spring off the flange plate. 8. Move the shoes toward each other until the adjusting bolt and connecting spring drop off. 9. Remove the clip holding the brake lever to the prim ary shoe (shoe with short lining). 10. Compress the spring on the brake cable and remove the cable from the lever. 11. If necessary to remove the anchor pin, straighten the w asher from pin hex and reinforcem ent. Rem ove reinforcem ent and washer with anchor pin. 12. If necessary to remove the cable, compress tangs on cable and pull assembly out of the hole in the flange plate. 13. If necessary to remove the flange plate, remove the transm ission flange nut and transm ission output flange. Rem ove bolts holding th e flange p late to bearing retainer and remove the flange plate. Inspection Replace any worn or broken parts. Installation NOTICE: Refer to "N o tice " on Page 1 of this section when installing fasteners in steps 1, 2 and 4 below. 1. Place the flange plate in position on the rear bearing retainer and fasten with four bolts. Torque bolts to 24 lb. ft. (33 N-m ). RETURN SPRINGS W AVE WASHER FLANGE LOCK BRAKE LEVER ANCHOR PIN STRUT ^ HOLD DOW N PIN STRUT GUIDE PLATE SPRING DRUM HOLD D O W N SPRING WASHER, SPRING , CUP SOCKET A D JU STIN G SCREW BACKING PLATE BRAKE CABLE Fig. 5 -4 7 -P ro p s h a ft Parking Brake Components I IG H T t r u c k s e r v i c e m a n u a l BRAKES 2. Install transm ission output flange on spline of mainshaft and fasten with flange nut. Torque nut to 100 lb. ft. (136 N-m). 3. Install cable assembly from back of flange plate. Push retainer through hole in flange plate until tangs se­ curely grip the inner side of the plate. 4. Place washer and reinforcem ent over the threaded end of anchor pin. Hold anchor pin nut (flat side against flange on flange plate) in position behind flange plate and insert threaded end of anchor pin from front side. T hread the anchor pin into nut and tighten securely (140 lb. f t . - 190 N -m ). Bend tan g of w asher over reinforcem ent and side of w asher over hex of anchor pin. 5. In stall lever on cable by com pressing spring and inserting cable in channel of lever. Release spring. 6. Install prim ary shoe (short lining) to lever as follows: Place pin in lever, place w asher on pin and push pin through hole in prim ary shoe. Fasten parts together by installing the clip in groove of pin. 7. Fasten two brake shoes and linings together by install­ ing connecting spring. Move the shoes toward each other and install adjusting screw. 8. L ubricate the flange plate contact surfaces with a very light coat of Delco Brake Lube (or equivalent). 9. Place shoe and linings in position on flange plate. W hen facing the brake assembly, the shoe with the short lining should be to th e left w ith the lever assem bled to it (autom atic transm ission), to the right (m anual transmission). 10. Pull brake shoes ap art and install stru t lever and spring between them . The loop on the stru t spring should be in the " u p " position. 11. Install hold down pins, washers, springs and cups from flange plate to shoes. 12. Place guide plate on anchor pin. 13. Install pull back springs. 14. Remove the "knock o u t" plug (if necessary) and install a new m etal plug in the brake drum adjusting hole. 15. Install the brake drum . 16. Install the propeller shaft. 5-43 m etal, while if left alone, the grooves and lining ridges m atch and satisfactory service can be obtained. If brake linings are to be replaced, a grooved drum should be turned for use with new linings. A grooved drum , if used with new lining, will not only wear the lining, but will m ake it difficult, if not impossible to obtain efficient brake perform ance. An out-of-round drum m akes ac cu rate brake shoe adjustm ent impossible and is likely to cause excessive wear of other parts of brake m echanism due to its eccentric action. An out-of-round drum can also cause severe and irregular tire tread wear as well as pulsating brake pedal. W hen the braking surface of a brake drum exceeds the factory specification limits in taper (and/or) being out-ofround, the drum should be turned to true up the braking surface. O ut-of-round as well as taper and wear can be accurately m easured with an inside m icrom eter fitted with proper extension rods. W hen m easuring a drum for out-of-round, taper and wear, take m easurem ents at the open and closed edges of m achined surface and at right angles to each other. Turning Brake Drums If a drum is to be turned, only enough m etal should be removed to obtain a true, smooth braking surface. If a drum does not clean-up when turned to a m axim um diam eter as shown in the general specification, it m ust be replaced. Removal of more m etal will affect dissipation of heat and may cause distortion of the drum . All brake drums have a maximum diameter cast into them. This diameter is the maximum wear diameter and not a refinish diameter. Do not refinish a brake drum that will not meet the specifications, as shown below, after refinishing. DRUM D IA M E TE R S O R IG IN A L MAXIMUM R E F IN IS H R E PL A C E M E N T (D ISC A R D ) 11.060 11.210 12.060 13.060 11.090 11.240 12.090 13.090 11.000 11.150 12.000 13.000 BRAKE DRUMS Brake Drum Balance Inspection and Reconditioning NOTICE: See "N o tice" on Page 1 of this section. W henever brake drum s are removed, they should be thoroughly cleaned and inspected for cracks, scores, deep grooves and out-of-round. A cracked drum is unsafe for fu rther service and must be replaced. Do not attem pt to weld a cracked drum . Sm ooth up any slight scores. H eavy or extensive scoring will cause excessive brake lining wear, and it will probably be necessary to rebore in order to true up the braking surface. If the brake linings are slightly worn and the drum is grooved, the drum should be polished with fine emery cloth but should not be turned. A t this stage, elim inating the grooves in drum would necessitate removal of too much D uring m anufacture, brake drum s are balanced. Any balance weights m ust not be removed. WHEEL CYLINDER Removal 1. Remove wheel, drum and brake shoes. Be careful not to get grease or dirt on brake lining. 2. Remove wheel cylinder from backing plate. Disassembly 1. Inspect cylinder bore for scoring or corrosion. It is best to replace a corroded cylinder. 2. Polish any discolored or stained area with crocus cloth by revolving cylinder on cloth supported by a finger. 3. Rinse cylinder in clean brake fluid. LIG H T T R U C K SERVICE M AN U AL 5-44 BRAKES 4. Shake excessive rinsing fluid from cylinder. Do not use a rag to dry cylinder, as lint from the rag cannot be kept from cylinder bore surfaces. Assembly 1. L ubricate cylinder bore and counterbore with clean brake fluid and insert spring-expander assembly. 2. Install new cups. (Be sure cups are lint and dirt free.) Do not lubricate cups prior to assembly. 3. Install new pistons. 4. Press new boots into cylinder counterbores by hand. Do not lubricate boots prior to assembly. Installation NOTICE: See "N o tic e " on page 1 of this section. 1. Install wheel cy linder on brak e backing plate and connect brake pipe to hose. Torque rear wheel brake LIG H T TR U C K SFR VICE M AN U AL pipe to wheel cylinder to specifications. 2. Install brake shoes, drum and wheel; then flush and bleed hydraulic system. POWER BRAKE VACUUM HOSE FILTER Removal 1. Use a pair of pliers to move the hose clam p approx­ im ately 2" (50 mm). 2. Twist the filter in the hose to break the seal and remove the filter. Installation 1. Install the filter. Be sure the vacuum check valve on the power brake unit is positioned from vertical as shown in figure(s) 5-48 and 5-49. 2. Position hose clam p to retain filter. BRAKES 5-45 C-K MODELS P MODELS Fig. 5-48--P ow er Brake Vacuum Hose Filter lnstallation--C-K-P Trucks LIG H T T R U C K SERVICE M A N U A L 5-46 BRAKES Fig. 5-49--Power Brake Vacuum Hose Filter lnstallation--G Models POWER BRAKE UNIT Vacuum Booster Replacement (Fig. 5-50) NOTICE: See "N o tic e " on page 1 of this section when installing fasteners referred to in steps 6, 7 and 9 below. 1. Remove two nuts holding m aster cylinder to power cylinder and position it away from power cylinder. Do not disconnect hydraulic brake lines; be careful not to bend or kink pipes. 2. Disconnect the vacuum hose from the vacuum check valve on the front housing of the power head. Plug vacuum hose to prevent dust and dirt from entering hose. 3. Disconnect the power brake push rod from the brake pedal. 4. Remove the four nuts from the m ounting studs which hold the power brake to the cowl. 5. C arry the power brake to a clean work area and clean the exterior of the power brake prior to disassembly. 6. M ount power brake assembly to cowl and torque nuts to specified torque. 9. Connect m aster cylinder to power cylinder and torque nuts to specifications. HYDRO-BOOST BRAKE SYSTEM NOTICE: Power steering fluid and brake fluid cannot be mixed. If brake seals contact steering fluid or steering seals contact brake fluid, seal dam age will result. T he following operations can be perform ed with the booster installed in the vehicle; exceptions to this statem ent m ay exist where Body M anufacturers sheet m etal ( " P " Models) would require removal of the booster from the vehicle. Pneumatic Accumulator CAUTION:The accumulator contains compressed gas. Always use proper tools and follow recom­ mended procedures or personal injury may result. Do not apply heat to accumulator. Do not attempt to repair an inoperative accumulator, always replace with a new accumulator. Dispose of an inoperative accumulator by drilling a 1/16" (1.6 mm) diameter hole through the end of the accu­ mulator can opposite the "O " ring. Removal 7. Connect power brake push rod to brake pedal. 1. T urn engine off and pum p brake pedal 4 or 5 times to deplete accum ulator. 8. C onnect vacuum hose to vacuum check valve. 2. Disconnect the high pressure hose. LIG H T TR U C K SE RV IC E M A N U A L BRAKES 5-47 4. Place the accum ulator retaining cap Tool J-26889 over the m aster cylinder stud and install the nut as shown in Figure 5-51. 5. Using Tool J-22269-01 or a large " C " clam p (6" (150 mm) m inim um ), depress the accum ulator. Insert a punch into the hole in the housing and remove retaining ring with a small screwdriver, (fig. 5-51). If the accum ulator is not easily compressed approx­ imately 1/8" (3 m m ) it is still charged. This indicates an internal problem with the accum ulator valves and the booster m ust be disassembled. 6. Slowly back off the clam p until tension on the accum u­ lator is released; remove accum ulator and "O " ring. Fig. 5-50--Vacuum Booster Installation 3. Remove two nuts from m aster cylinder, then move m aster cylinder away from booster with brake lines attached. Installation 1. Using clean power steering fluid, lubricate accum ulator seal. Install seal and accum ulator in housing and then place the retaining ring over the accum ulator (fig. 5-52). Place Tool J-26889 over accum ulator. 2. Using Tool J-22269-01 or a large " C " clamp (6 " (150 mm ) m inim um ) depress the accu m u lato r m aking certain th a t the accum ulator is compressed straight (fig. 5-51). 3. Snap the retaining ring into the housing groove by pushing it down all the way around w ith a sm all screwdriver. 4. Remove Tool J-22269-01 or " C " clam p and retaining cap Tool J-26889. Carefully check to make sure the retaining ring was completely installed properly. 5. Connect high pressure hose and check power steering fluid. 6. Install the m aster cylinder two nuts and accum ulator retaining cap Tool J-26889 and close the vehicle hood. Test the unit by starting the engine and turning the steering wheel from stop to stop a few times. Turn off engine and apply brake pedal 4 or 5 times. 7. Remove accum ulator retaining cap Tool J-26889 and install m aster cylinder nut. LIG H T T R U C K SERVICE M A N U A L 5-48 BRAKES NOTICE: See "N o tic e " on Page 1 of this section. Spool Valve Plug Removal 1. T urn engine off and pum p brake pedal 4 or 5 times to deplete accum ulator. 2. Remove two nuts from m aster cylinder, then move m aster cylinder aw ay from booster with brake lines attached. 3. Push spool valve plug in and use a sm all screwdriver to remove retaining ring (fig. 5-53). 4. Remove spool valve plug and " O " ring. Installation 1. Install " O " ring and spool valve plug (fig. 5-53). 2. Push spool valve plug in and install retaining ring. 3. Install m aster cylinder and two nuts to booster. NOTICE: See "N o tic e " on Page 1 of this section. 4. Bleed system. R efer to "H Y D R O -B O O S T B LEED ­ IN G P R O C E D U R E ". SPOOL RETURN SPRING “ O" RING SPOOL 'P LU G SPOOL PLUG RETAINER Fig. 5-54--Removing Tube Seat L IG H T T R U C K SERVICE M A N U A L Tube Seat Replacement 1. T urn engine off and pum p brake pedal 4 or 5 tim es to deplete accum ulator. 2. Clean dirt around fitting before removing fitting, then disconnect pressure hose a t Hydro-Boost and secure hose in a raised position to prevent loss of fluid. 3. To prevent m etal chips from entering booster, pack inside of tube seat with petrolatum . 4. Remove tube seat using N o. 4 easy-out as shown in Figure 5-54. 5. W ipe p etro latu m from housing and clean housing thoroughly to remove any m etal chips or dirt. 6. Install tube seat with Tool J-6217 as shown in Figure 5-55. 7. Fill and bleed system. R efer to "H Y D R O -B O O S T B L E E D IN G P R O C E D U R E ". BRAKES ^ 5-49 G MODELS MOTOR HOME CHASSIS MODELS P MODELS (EXCEPT MOTOR HOME) Fig. 5-56--Booster Installation (Hydro-Boost) LIG H T T R U C K SERVICE M AN U AL 5-50 BRAKES Fig. 5 -5 7 -P o w e r Steering Hose R o uting -C -K M odels LIG H T T R U C K SERVIC E M A N U A L BRAKES 5-51 Fig. 5 -5 8 -P o w e r Steering Hose R o uting -G M odels LIG H T T R U C K SERVICE M A N U A L 5-52 BRAKES LIG H T T R U C K SERVICE M A N U A L BRAKES Hydro-Boost Unit Replacement (fig. 5-56 thru 5-59) 1. D epress and release th e b rak e pedal several tim es (engine not running) to be sure th at all pressure is discharged from the accum ulator prior to disconnectiong the hoses from the booster. 2. P30(32) Models- Raise the vehicle on a hoist. 3. Clean all dirt from the booster at the hydraulic line connections and m aster cylinder. 4. Rem ove th e nuts and lockw ashers th a t secure the m aster cylinder to the booster and the support bracket. S upport the m aster cylinder, being careful to avoid kinking or bending the hydraulic lines attached to the m aster cylinder. Cover the end of the m aster cylinder with a clean cloth. It should not be necessary to disconnect the hydraulic lines from the m aster cylinder. 5. Disconnect the hydraulic lines from the booster ports. Plug all lines and the booster ports to prevent loss of fluid and to keep out foreign m aterial. 6 . P30(42) and C-K-G Modelsa. Rem ove booster pedal push rod co tter pin and w asher and disconnect the push rod from the brake pedal (C and K models) or booster bracket pivot lever (G and P models). 5-53 b. Remove the lower dash trim , then lower the steering column on C and K models. Remove support braces on P30 (42) models. c. Remove the booster bracket to dash panel or support bracket nuts and remove the booster assembly. 7. P30(32) Modelsa. Remove the cotter pin, nut, bolt and washers th at secure the operating lever to the vertical brake rod. b. Remove the six nuts, lock w asher and bolts th at secure the booster linkage bracket to the front and rear support brackets, and remove the booster from the vehicle by sliding the booster off the rear support studs. c. Remove the cotter pin, nut, washer and bolt th at secures the operating lever to the pedal rod. d. Remove the brake pedal rod lever nut and bolt and then remove the lever, sleeve and bushings. 8. To install, reverse Steps 1-7 above. Torque all hydraullic lines and attaching bolts to specifications. L u b ricate pedal rod and linkage pivot bolts, pins, sleeves and bushings w ith Delco B rake L ube (or equivalent). NOTICE: See "N o tice " on Page 1 of this section. 9. Fill and bleed system. R efer to "H ydro-Boost bleeding procedure." 10. Check brake pedal and stoplam p switch adjustm ent. SPECIFICATIONS BRAKE SYSTEM DESCRIPTION JB5 Low Drag JB6 Low Drag JB7 Conventional JB8 Conventional JF9 Conventional REAR BRAKES FRONT BRAKES GASOLINE ENGINE VEHICLES C-MODELS Drum 11.00 x 2.00 Disc 11.86 x 1.04 Drum 11.00 x 2.00 Disc 11.86 x 1.04 G-MODELS Drum 11.00 x 2.00 Disc 11.86 x 1.28 Drum 11.00 x 2.00 Disc 11.86 x 1.28 ALL MODELS Drum 11.15 x 2.75 Disc 11.86 x 1.28 Drum 11.15 x 2.75 Disc 12.50 x 1.28 Drum 13.00 x 2.50 Disc 12.50 x 1.28 Drum 13.00 x 3.50 Disc 12.50 x 1.53 Disc 13.75 x 1.53 Disc 14.25 x 1.53 JD3 Low Drag JD5 Low Drag DIESEL ENGINE VEHICLES Drum 11.00 x 2.00 Disc 11.86 x 1.28 Drum 11.15 x 2.75 Disc 11.86 x 1.28 SYSTEM JB1 Low Drag JB3 Low Drag JB1 Low Drag JB3 Low Drag BRAKE ASSIST None (Manual Brakes) Vacuum — Single Diaphragm None (Manual Brakes) Vacuum — Single Diaphragm Vacuum — Dual Diaphragm Vacuum — Dual Diaphragm Vacuum — Dual Diaphragm Hydraulic — Hydroboost Hydraulic — Hydroboost Hydraulic — Hydroboost Hydraulic — Hydroboost LIG H T T R U C K SERVICE M A N U A L 5-54 BRAKES SPECIFICATIONS c M aster C y lin d e r — to Dash o r B o o ste r K P G **3 4 N .m (25 ft. lbs.) **3 4 N .m (25 ft. lbs.) 34 N .m (25 ft. lbs.) B o o ste r to Dash o r Fram e **3 4 N .m (25 ft. lbs.) **3 4 N .m (25 ft.lb s.) 34 N .m (25 ft. lbs.) 34 N«m (25 ft. lbs.) C o m b in a tio n Valve — M o u n tin g B o lts 17 N*m (150 in.lbs.) 17 N .m (150 in. lbs.) 23 N .m (17 ft. lbs.) 23 N«m (17 ft. lbs.) 34 N«m 125 ft. lb s .l 48 N .m (35 ft. lbs.) 34 N .m (25 (t. lbs.I C a liper — — _ — B ra cke t M o u n tin g B o lt _ S u p p o rt Plate to K n u ckle Brake Pedal — 16 N*m (140 in. lbs.) B ra c k e t to Dash 34 N .m (25 ft. lbs.) 34 N .m (25 ft. lbs.) — B ra c k e t to I.P. 34 N .m (25 ft. lbs.) 34 N .m (25 ft. lbs.) — — Pivot B o lt Nut 34 N .m (25 ft. lbs.) 34 N .m (25 ft. lbs.) — — Sleeve to B ra cke t — S to p la m p S w itch B ra cke t — Push Rod to Pedal — Push Rod A d ju s tin g Nut Parking B rake — to Dash 34 N .m (25 ft. lbs.) — 17 N .m (150 in. lbs.) — 34 N .m (25 ft. lbs.) — 34 N .m (25 ft. lbs.) — — 9.5 N»m (85 in. lbs.) 34 N .m (25 ft. lbs.) — — 34 N .m (25 ft. lbs.) — — — 34 N .m (25 ft. lbs.) — 30 N .m (22 ft. lbs.) 12 N*m (100 in. lbs.) 12 N .m (100 in. lbs.) 12 N*m (100 in. lbs.) — to I.P., K ick Panel o r F loorpan 17 N .m (100 in. lbs.) 17 N»m (100 in. Jbs.) 12 N*m (100 in. lbs.) 24 N .m (18 ft. lbs.) — Cable C lip s — Screw s 17 N«m (150 in. lbs.) — 12 N*m (100 in. lbs.) 17 N*m (150 in. lbs.) B o lts 17 N .m (150 in. lbs.) — 24 N .m (18 ft. lbs.) 6 N«m (55 in. lbs.) — P ro p sh aft P arking Brake — A d ju s tin g Nut — _ _ _ 40 N»m (30 ft. lbs.) — — — 27 N»m (20 ft. lbs.) — Cable C lip to Fram e — — — 17 N .m (150 in. lbs.) — Cable C lip to Dash — — — 6 N .m (55 in. lbs.) — Cable C lip to Trans. B rkt. — — — 27 N .m (20 ft. lbs.) — Flange Plate — — — 40 N .m (30 ft. lbs.) — Drum — — — 110 N .m (80 ft. lbs.) — B ra cke t to Trans. Wheel C ylin d e r to F lange Plate B o lt 5.5 N*m (50 in. lbs.)/20 N*m (180 in. lbs.) on JB5, JB6, JB 7 and JB8 Rear Brake A n c h o r Pin 190 N .m (140 ft. Ibs.)/312 N .m (230 ft. lbs.) JB 7 and JB8) F ro n t Brake Hose — to C a lip e r 44 N«m (32 ft. lbs.) — to Fram e Nut — B ra cke t B o lt 7 N«m (58 in. lbs.) 17 N«m (150 in. lbs.) — Rear Brake Hose — to A xle B ra cke t *17 N .m (150 in. lbs.) *17 N .m (150 in. lbs.) — 17 N .m (150 in. lbs.) 17 N«m (150 in. lbs.) 17 N«m (150 in. lbs.) 17 N .m (150 in. lbs.) B ra cke t to Axle Brake Line — A tta c h in g Nuts — — 17 N .m (150 in. lbs.) 17 N .m (150 in. lbs.) 17 N*m (150 in. lbs.) 17 N .m (150 in. lbs.) R e ta in in g C lip s — — Screws B o lts — — Brake B le e d e r Valves H yd ro-B o o st — — Pedal Rod — 17 N .m (150 in. lbs.) 10 N*m (90 in. lbs.) 12 N*m (100 in. lbs.) 17 N*m (150 in. lbs.) 17 N*m (150 in. lbs.) 24 N .m (18 ft. lbs.) 7 N»m (60 in. lbs.) _ _ _ — — — 20 N-m (15 ft. lbs.) Pivot Lever Rod R etainer — — — 34 N .m (25 ft. lbs.) — Pivot Lever B o lt — — — 60 N .m (45 ft. lbs.) — B o o ste r B ra cke ts — — — 34 N .m (25 ft. lbs.) — — — 17 N»m (150 in. lbs.) P30 (32) M odels — Pedal Rod B o o t — — P30 (32) M odels — B o o ste r Brace at Dash o r Rad. Supt. — Pow er S teering Pum p to B o o ste r Line 34 N*m (25 ft. lbs.) — B o o ste r to Gear Line 34 N .m (25 ft. lbs.) — R eturn Line at B o o ste r and Gear 34 N .m (25 ft. lbs.) — R eturn Lin e C lam p S crew 1.6 N«m (15 in. lbs.) — Line C lam p to B ra cke t Screw 17 N .m (150 in. lbs.) — Hose C lam p to S k irt S crew 4.6 N»m (40 in. lbs.) — — — 17 N .m (150 in lbs.) — — Lin e C lam p to Fram e B o lt *27 N.m (20 ft. lbs.) **4 4 N«m (32 ft. lbs.) — Master Cylinder to Booster — Master Cylinder or Booster to Dash Reinforcement L IG H T T R U C K SE RV IC E M AN U AL 34 N .m (25 ft. lbs.) — 17 N*m (150 in. lbs.) (CKP20-30) BRAKES 5-55 SPECIAL TOOLS 1. 2. 3. 4. 5. 6. 7. J-25310 Tubing Bender J23530 Flaring Tool J-23533 Tubing Cutter J-25085 Socket J-8049 or J-22348 Spring Remover J-21177 or J-22364 Drum/Shoe Gauge J-21472 or J-22364 Bleeder Wrench L IG H T T R U C K SERVICE M A N U A L 8. J-22904 Dust Boot Installer J-28735 Dust Boot Installer (JB7) 9. J-24548 Dust Boot Installer 10. J-26889 Accumulation Piston Compressor 11 • J-23709 Combination Valve Pin Retainer 12. J-23518 Pressure Bleeder Adater 13. J-26819 Pressure Bleeder Adapter 1 4 . J-26819-25 Bleeder Adapter Clamp (Long) 15. J-26819-30 Bleeder Adapter Extension /* * a --’ c\ (■ f I =■I ...* • *:.#•"'■ ' ■ '■ "5*. V •- •, 1 !:: Jl \ /p \ m - a '" . ■ , • h i ■ 'V> / $ . >e« < §> :A:: ii ' Vtoe* »/ 1u *0Vi’c - .*i - '" S i ) \ V I ,. o* - ' : u 0 : • '•. • •••'Ortrc^ /w rtfi* n^i*£i*'ji't' m.>A' Cl ]: . *»r- I ’" ^ ft* r ‘", . » L ‘ ■• *^^V': , ? . «. : - - 0 yc.- "'•. ' n&Uf'^K * \ f * ^ . -* J - t j (v ' >*;■' h ii > t n ’< v '.i l O M >r » ? * & 2 “ ' ■ .** e v a ^ .? ^sV, - v . v : :•**. ••’ o - W 3 c X - ? , .**i T fH . r j r * t v> f . r . : ' : v . f i J \ ' , t i 3** I , 0 ^ . ; 'a - .* :,-d \ ’ '' - •■■: ' “ * vf -v • ; . ': ’ t r r < - . * r» '* t * ■' \ ENGINE 6-1 SECTION 6 ENGINE CONTENTS E N G IN E D IA G N O S IS Engine Perform ance D iagnosis............................. .....6-1 Engine M echanical Diagnosis - G asoline.......... .....6-10 Engine M echanical Diagnosis - D iesel............... .....6-14 Engine Diagnosis - Electronic Spark C o n tro l... .....6D-1 E N G IN E - G A S O L IN E 4.1 L (250) V IN (D) L -L -R P O L E 3................ — 6 A 1-1 4.8 L (292) VIN (T) L -6 -R P O L 2 5 ................. — 6 A 1-1 5.0 L (305) V IN (G ) V -8 -R P O L G 9................ — 6 A 4 -1 5.0 L (305) V IN (F) V -8 -R P O L F 3 ................. .... 6A4-1 5.0 L (305) V IN (H ) V -8 -R P O L E 9 ................ .... 6A4-1 5.7 L (350) V IN (L) V -8 -R P O L S 9 .............. ........6A4-1 5.7 L (350) V IN (M ) V -8 -R P O L T 9 ............ ....... 6A4-1 7.4 L (454) V IN (W ) V -8 -R P O L E 8 ............ ........ 6A5-1 E N G IN E - D IE SE L 5.7 L (350) V IN (Z ) V -8 -R P O L F 9 ............. ........6A6-1 E N G IN E C O O L IN G ........................................... .........6B-1 E N G IN E F U E L ..............................................................6C-1 E N G IN E E L E C T R IC A L .................................... ........ 6D-1 E N G IN E E M IS S IO N C O N T R O L S ............... ....... 6E-1 C O M P U T E R C O M M A N D C O N T R O L ................ 6E1-1 E N G IN E E X H A U S T ........................................... ........ 6F-1 E N G IN E P E R F O R M A N C E S P E C IF IC A T IO N S 6G-1 ALL N E W G E N E R A L M O T O R S V E H IC L E S A R E C E R T IF IE D BY T H E U N IT E D STA TES E N V IR O N M E N ­ T A L P R O T E C T IO N A G E N C Y AS C O N F O R M IN G TO T H E R E Q U IR E M E N T S O F T H E R E G U L A T IO N S FOR T H E C O N T R O L O F A IR P O L L U T IO N FRO M N E W M O TO R V E H IC L E S. T H IS C E R T IF IC A T IO N IS C O N T IN ­ G E N T ON C E R T A IN A D JU S T M E N T S BEIN G SE T TO FA C T O R Y ST A N D A R D S . IN M OST C A SES, TH ESE A D JU S T M E N T PO IN T S E IT H E R H A V E BEEN P E R M A N E N T L Y S E A L E D A N D /O R M ADE IN A C C E SSIB L E TO PR E V E N T IN D IS C R IM IN A T E O R R O U T IN E A D JU S T M E N T IN T H E FIELD . FOR T H IS R E A S O N , THE F A C T O R Y P R O C E D U R E FO R T E M P O R A R IL Y R E M O V IN G PL U G S , C A P S , E TC ., FOR P U R P O S E S O F S E R V IC IN G T H E P R O D U C T M U S T BE S T R IC T L Y F O L L O W E D A N D , W H E R E V E R P R A C T IC A B L E , R E T U R N E D TO T H E O R IG IN A L IN T E N T O F T H E D E SIG N . GENERAL INFORMATION STATEMENT ON CLEANLINESS AND CARE An autom obile engine is a com bination of m any m achined, honed, polished and lapped surfaces with toler­ ances th at are measured in the ten thousands of an inch. W hen any internal engine parts are serviced, care and cleanliness are im portant. A liberal coating of engine oil should be applied to friction a reas d uring assem bly to p rotect and lu b ricate the su rfaces on initial operation. T hroughout this section, it should be understood that proper cleaning and protection of machined surfaces and friction areas is part of the repair procedure. This is considered standard shop practice even if not specifically stated. W henever valve train com ponents are removed for service, they should be retained in order. At the tim e of installation, they should be installed in the same locations and with the sam e m ating surfaces as when removed. Battery cables should be disconnected before any major work is performed on the engine. Failure to disconnect cables may result in dam age to wire harness or other electrical parts. GENERAL INFORMATION ON ENGINE SERVICE T H E F O L L O W IN G IN F O R M A T IO N ON E N ­ G IN E S E R V IC E S H O U L D BE N O T E D C A R E FU L L Y , AS IT IS IM P O R T A N T IN P R E V E N T IN G D AM AGE, A N D IN C O N T R IB U T IN G TO R ELIA B LE E N G IN E PERFO RM A N CE. W hen raising or supporting the engine for any reason, do not use a jack under the oil pan. Due to the small clearance between the oil pan and the oil pump screen, jacking against the oil pan may cause it to be bent against the pump screen resulting in a dam aged oil pick-up unit. It should be kept in mind, while working on the engine, that the 12-volt electrical system is capable of violent and dam aging short circuits. W hen perform ing any work where electrical term inals could possibly be grounded, the ground cable of the battery should be disconnected at the battery Any tim e the carburetor or air cleaner is removed, the intake opening should be covered. This will protect against accidental entrance of foreign m aterial which could follow the intake passage into the cylinder and cause extensive dam age when the engine is started. LIG H T T R U C K SERVICE M AN U AL 6-2 ENGINE IN THE M E C H A N IC A L PR O C E D U R ES DESCRIBED IN TH IS SECTIO N , G E N E R A L L Y NO R EFEREN C ES W IL L BE M A D E TO T H E REM O V A L OF O P T IO N A L E Q U IP M E N T SUCH AS PO W ER STEER IN G PU M P, A IR C O N D IT IO N IN G COM PRESSOR, ETC. SH O U LD IT BECO M E N ECESSA RY TO REM OVE \N Y SUCH ITEM TO P E R FO R M O T H E R SERVICE, R.EFER TO T H E A P P R O P R IA T E SECTIO N O F TH IS SERVICE M A N U A L FO R SPE C IFIC IN FO R M A T IO N . Each Symptom is defined, and it is vital that the correct one be selected based on the com plaints reported or found. Review the Symptoms and their definition to be sure that only the correct term s are used. The words used may not be what you are used to in all cases, but because these term s have been used interchangeably for so long, it was necessary to decide on the most common usage and then define them. If the definition is not understood, and the exact Symptom is not used, the Diagnostic procedure will not work. It is im portant to keep two facts in mind: INTRODUCTION Engine Perform ance Diagnosis procedures are guides that will lead to the most probable causes of engine performance complaints. They consider all of the components of the fuel, ignition, and mechanical systems that could cause a particular com plaint, and then outline repairs in a logical sequence. It is im portant to determ ine if the “ Check Engine” light is “ON” or has come “O N ” for a short interval while driving. If the “ Check Engine” light has come “O N ” , the Computer Com m and Control System should be checked for stored “Trouble Codes” (See Section 6E) which may indicate the cause for the perform ance complaint. 1. The procedures are w ritten to diagnose problems on cars that have “ run well at one tim e” and that time and wear have created the condition. 2. All possible causes cannot be covered, particularly with regard to emission controls. If doing the work prescribed does not correct the com plaint, then either the wrong Symptom was used or a m ore detailed analysis will have to be made. All of the Symptoms can be caused by worn out or defective parts such as Spark Plugs, Ignition Wiring, etc. If time a n d /o r mileage indicate that parts should be replaced, it is recommended that it be done. The procedures are based on Symptoms that are listed in che Table of Contents. SYMPTOM DEFINITION A. Dieseling Engine continues to run after the switch is turned off. It runs unevenly and makes knocking noises. B. D etonation A mild to severe ping, usually worse under acceleration. The engine makes sharp metallic knocks that change with throttle opening. Sounds like pop corn popping. C. & D. Stalls, Cold or H ot The engine quits running. It may be at idle or while driving. C. & D. Rough Idle, Cold or Hot The engine runs unevenly at idle. If bad enough, it may make the car shake. E. Miss Steady pulsation or jerking that follows engine speed, usually more pronounced as engine load increases. N ot normally felt above 1500 rpm or 30 mph. The exhaust has a steady spitting sound at idle or low speed. F. Hesitates M om entary lack of response as the accelerator is depressed. Can occur at all car speeds. Usually most severe when first trying to make the car move, as from a stop sign. May cause the engine to stall if severe enough. G. Surges Engine power variation under steady throttle or cruise. Feels like the car speeds up and slows down with no change in the accelerator pedal. H. Sluggish Engine delivers limited power under load or at high speed. W on’t accelerate as fast as normal; loses too much speed going up hills, or has less top speed than normal. I. Spongy Less than the anticipated response to increased throttle opening. Little or no increase in speed when the accelerato r pedal is pushed down a little LIG H T T R U C K SERVICE M AN U AL ENGINE 6-3 to increase cruising speed. C ontinuing to push the pedal down will finally give an increase in speed. J. Poor Gas Mileage Self describing. K. Cuts O ut The engine exhibits a significant or total tem porary loss of power at sharp, irregular intervals. This may occur repeatedly or interm ittently and is usually worse under heavy acceleration. L. H ard Start - Cold Self describing M. H ard Start - Hot Self describing ENGINE PERFORMANCE DIAGNOSIS A. Dieseling 1. Make visual checks of the following for sticking. a. Carburetor, choke, and throttle linkage b. Fast idle cam See cleaning, inspection, and adjustm ent of carburetor, Section 6C. 2. See ISC diagnosis if applicable. 3. Check and reset ignition timing and idle speed settings. Refer to emission la 4. Remove carbon with top engine cleaner. Follow instructions on can. If condition still exists, suggest that owner try different gasoline. B. D etonation 1. Check for obvious overheating problems. a. Low coolant b. Loose fan belt c. Restricted air flow, etc. 2. For “ non-EST” check ignition timing per emission control inform ation label. 3. For “ EST or ESC” see diagnosis Section 6D, 6E. 4. Perform EG R functional check see Section 6E. 5. Remove carbon with top engine cleaner. Follow instructions on can. If condition still exists, suggest that owner try different gasoline. C. Stalls or Rough Idle - Cold 1. W ith engine running, remove air cleaner cover and filter. D am per door in air cleaner snorkel should be closed when engine is cold. It may be necessary to place cold wet rag over sensor to close it if engine is too warm. If dam per door does not close, apply vacuum directly to vacuum motor. If door closes, replace sensor. If door stays open, replace vacuum motor. 2. Visually check the following: a. H ot air tube to air cleaner connection and condition of hot air stove. b. Vacuum hoses for splits, kinks and proper connections. See Hose R outing Schematic on Vehicle Emission Control Inform ation Label. c. A ir leaks at carburetor m ounting and intake manifold. d. Ignition wires for cracking, hardness and proper connections. R epair or replace as necessary. LIG H T T R U C K SERVICE M A N U A L 6-4 ENGINE 3. Check the following for sticking: a. Carburetor, choke, and throttle linkage. b. Fast idle cam. c. C arburetor flooding. See cleaning, inspection and adjustm ent of carburetor, Section 6C. 4. W ith engine running, visually check vacuum break linkage for movement while removing and reinstalling vacuum hose. If the linkage does not move and vacuum is at hose, replace vacuum break assembly. 5. W ith engine off, check all choke adjustments. See Section 6C. 6. Check engine timing and idle speed. See Emission Control Inform ation Label. 7. Remove vacuum hose from E.G .R. valve and connect an extra hose from any manifold vacuum source to valve. If rpm doesn’t drop, valve is leaking. See E.G .R. Section 6E for further functional tests, cleaning, a n d /o r replacement. 8. Check E.F.E. valve. D isconnect E.F.E. hose from tube and connect an extra vacuum hose from any manifold vacuum source to E.F.E. tube. Observe actuator linkage for movement. If no movement, repair as necessary. Refer to Section 6E for further test a n d /o r repair. D. Stalls or Rough Idle - Hot 1. W ith engine running, remove air cleaner cover and filter. D am per door in air cleaner snorkel should be open. If closed and engine is hot, check tem perature operation of sensor unit. See air cleaner tem perature test, Section 6E. 2. Visually check the following: a. Vacuum hoses for splits, kinks and proper connections. See hose routing Schematic, Vehicle Emission Control Inform ation Label. b. A ir leaks at carburetor m ounting and intake manifold. c. Ignition wires for cracking, hardness and proper connections. Repair or replace as necessary. d. Check idle solenoid - Replace as necessary - See idle solenoid Section 6E. 3. Check engine tim ing and idle speed. See emission control inform ation label. 4. Check P.C.V. valve for proper operation by placing finger over inlet hole in valve end several times. Valve should snap back. If not, replace valve. 5. Remove vacuum hose from E.G .R. valve and connect an extra hose from any manifold source to valve. If rpm doesn’t drop, valve is leaking. See E.G.R. Section 6E for further functional tests, cleaning a n d /o r replacement. 6. Remove carbon with top engine cleaner. Follow instructions on can. If idle is still rough, run a cylinder compression check. E. Miss LIG H T T R U C K SERVICE M A N U A L 1. Visually check the following: a. Vacuum hoses for splits, kinks and proper connections. See hose routing Schematic, Vehicle Emission Control Inform ation Label. b. A ir leaks at carburetor m ounting and intake manifold. c. Ignition wires for cracking, hardness and proper connections. Repair or ENGINE 6-5 replace as necessary. 2. Disconnect air cleaner and E.G .R. vacuum hoses and cap both vacuum sources. 3. Remove one spark plug wire at a time with insulated pliers. If there is an rpm drop on all cylinders, go to rough idle (hot) diagnosis charts. 4. If there is no rpm drop on one or more cylinders (See Section 6D Interm ittent Operation or Miss), remove spark plug(s) and check for: a. Cracks b. W ear c. Im proper gap d. Burned Electrodes e. Heavy Deposits Repair or replace as necessary. 5. Check spark plug wires by connecting ohm m eter to ends of each wire in question. If m eter reads over 50,000 ohms, replace wire(s). : ' ' 6. Visually check distributor cap and rotor for moisture, dust, cracks, burns, etc. Clean a n d /o r repair as necessary. 7. Perform compression check on questionable cylinder(s). If compression is low, repair as necessary. 8. Remove rocker covers. Check for bent push rods, worn rocker arms, broken valve springs, worn cam shaft lobes. Repair as necessary. Laaofte tx'iiros'/ .m jjuzsv "clr.viqQf b m ■jinyq rtujsz&v I'bsmit-O F. Hesitates 1. Visually check the following: a. Vacuum hoses for splits, kinks and proper connections. See hose routing charts, Section 6E. b. A ir leaks at carburetor m ounting and intake manifold. c. Check ignition wires for cracking, hardness and proper connections. Repair and replace as necessary. 2. Note: Cold Engine Only Check the following for sticking or faulty operation: a. C arburetor, choke, and throttle linkage. b. Fast idle cam. See cleaning, inspection and adjustm ent of carburetor, Section 6C. 3. Check carburetor accelerator pum p operation. W ith air cleaner removed and engine off, hold choke valve open and look for gas squirt in carburetor bore while moving throttle. 4. If weak or no pump squirt, remove carburetor air horn and repair pum p system as necessary. See air horn removal, cleaning and inspection, Section 6C for proper procedures. Check float level adjustm ent before replacing air horn and pum p rod adjustm ent after assembly. See Float Adjustm ent, Section 6C. 5. Disconnect and plug vacuum advance hose,(Non-EST) on EST equipped engines disconnect EST connector, connect tachom eter and timing light. Check ignition timing and idle speed against specs on emission label. 6. W ith engine running, remove air cleaner cover and filter. D am per door in LIG H T T R U C K SERVICE M A N U A L 6-6 ENGINE air cleaner snorkel should be closed when engine is cold. It may be necessary to place cold wet rag over sensor to close if engine is too warm. If dam per door does not close, apply vacuum directly to vacuum motor. If door closes, replace sensor. If door stays open, replace vacuum motor. 7. Check TPS adjustm ent if applicable see Section 6C. G. Surges 1. W ith engine running, remove air cleaner cover and filter. D am per door in air cleaner snorkel should be closed when engine is cold. It may be necessary to place cold wet rag over sensor to close if engine is too warm. 2. Visually check the following: a. Vacuum hoses for splits, kinks and proper connections. See hose routing Schematic, Vehicle Emission Control Inform ation Label. b. A ir leaks at carburetor m ounting and intake manifold. c. Ignition wires for cracking, hardness and proper connections. R epair or replace as necessary. 3. “ Non EST” check ignition timing per emission control inform ation label. To check m echanical advance, observe timing marks. It should advance as throttle is opened and return to m ark as throttle is closed. Check EST operation if applicable. 4. “ Non EST” with engine off, remove vacuum hose from distributor vacuum advance Connect vacuum pum p and apply 15" vacuum. Vacuum should hold steady for 15 seconds. If vacuum drops, replace vacuum advance unit. 5. Check carburetor fuel inlet filter. Replace if dirty or plugged. 6. Test fuel pum p by connecting hose from carburetor fuel feed line to a suitable container. Start engine and let idle for 15 seconds. a. M echanical pum p should supply 1/2 pint or more. If not, go to step 7. If O K, go to step 9. 7. To check m echanical fuel pum p connect a vacuum gage. Crank or run engine until m aximum vacuum is reached. If less than 12 inches, replace pump. If vacuum reading is 12 inches or more, go to step 8. 8. Check fuel lines and hoses for splits, leaks or kinks by disconnecting each section of line and connect vacuum gage. Crank or run engine until vacuum gage peaks. Vacuum should be at least 12 inches. If less, repair or replace defective line or hose. 9. If fuel lines and pum p check O K , remove tank unit, replace strainer and clean fuel tank, if necessary. 10. Remove spark plugs, Check for cracks, wear, im proper gap, burned electrodes, heavy deposits. R epair or replace as necessary. LIG H T T R U C K SERVICE M A N U A L ENGINE H. Sluggish or Spongy 6-7 1. Rem ove air cleaner and check air filter for dirt or being plugged. Replace as necessary. 2. W ith engine running, dam per door in air cleaner snorkel should be closed when engine is cold. It may be necessary to place cold wet rag over sensor to close if engine is too warm. If dam per door does not close, apply vacuum directly to vacuum m otor. If door closes, replace sensor. If door stays open, replace vacuum m otor. 3. Check ignition timing per em ission label. Without EST check m echanical advance as throttle is opened and closed. Check EST if applicable see Section 6C-6E. 4. Remove air cleaner and check for full throttle valve opening in carburetor by depressing accelerator pedal to floor; also check for full choke valve opening and free operating air valve (if equipped). R epair as necessary. See carburetor cleaning and inspection, Section 6C. 5. Rem ove vacuum hose from E.G .R . valve and connect an extra hose from any m anifold vacuum source to valve. If rpm doesn’t drop, valve is leaking. See E .G .R . Section 6E for further functional tests, cleaning, a n d /o r replacem ent. 6. “ N on EST” with engine off, remove vacuum hose from distributor vacuum advance vacuum pum p and apply 15" vacuum. Vacuum should hold steady for 15 seconds. If vacuum drops, replace vacuum advance unit. 7. Remove spark plugs. Check for cracks, wear, im proper gap, burned electrodes, heavy deposits. Repair or replace as necessary. 8. Remove carburetor air horn and check the following: a. Power piston for freeness b. D irt in carburetor c. Float adjustment d. M etering rods e. Power valve(s) Refer to carburetor cleaning and inspection, Section 6C. I. Poor Gasoline Mileage 1. W ith engine running, remove air cleaner cover and filter. Check filter for dirt or being plugged. Replace as necessary. D am per door in air cleaner snorkel should be closed when engine is cold. It may be necessary to place cold wet rag over sensor to close it if engine is too warm. If dam per door does not close, apply vacuum directly to vacuum motor. If door closes, replace sensor. If door stays open, replace vacuum motor. 2. Visually check the following: a. Vacuum hoses for splits, kinks and proper connections. See hose routing Schematic, Vehicle Emission Control Inform ation Label. b. A ir leaks at carburetor m ounting and intake manifold. c. Ignition wires for cracking, hardness and proper connections. Repair or replace as necessary. 3. Check ignition timing per emission control information label. “ Non EST” To check mechanical advance, observe timing mark. It should advance throttle is opened and return to m ark as throttle is closed. LIG H T TR U C K SERVICE M A N U A L 6-8 ENGINE Check EST if applicable, Section 6D-6E. 4. Check carburetor choke linkage and settings. Clean and repair as necessary. See carburetor choke adjustments, cleaning and inspection, Section 6C. 5. “N O N EST” with engine off, remove vacuum hose from distributor vacuum advance vacuum pum p and apply 15" vacuum. Vacuum should hold steady for 15 seconds. If vacuum drops, replace vacuum advance unit. 6. Remove spark plugs, check for cracks, wear, im proper gap, burned electrodes, heavy deposits. Repair or replace as necessary. 7. I f in p re v io u s c h eck s, a d ju s tm e n ts have n o t b e e n m ad e th a t c o u ld im p ro v e m ileag e, rem o v e c a rb u re to r air h o rn an d c h e ck th e fo llow ing: a. b. c. d. e. See Power piston for freeness D irt in jets and metering passages M etering rods Power valve(s) Float adjustm ent carburetor cleaning, inspection, and adjustments, Section 6C. 8. Suggest owner fill tank and recheck mileage. J. Cuts O ut 1. Check ignition wires, boots, cap and coil for: a. Dam age b. D eterioration c. Loose connections d. Carbon tracking Clean, tighten a n d /o r replace defective parts as necessary. 2. Check ignition system - See Section 6E. Check distributor for: a. W orn shaft b. Bare or shorted wires R epair or replace defective parts as necessary. 3. Remove spark plugs. Check for cracks, wear, im proper gap, burned electrodes, heavy deposits. R epair or replace as necessary. 4. Check carburetor fuel inlet filter. Replace if dirty or plugged. 5. Test fuel pum p by connecting hose from carburetor fuel feed line to a suitable container. Start engine and let idle for 15 seconds. a. F u e l pump should supply 1/2 pint or more. If not, go to step 7. 6. To check m echanical fuel pum p, disconnect inlet hose at pum p and connect a vacuum gage. C rank or run engine until m axim um vacuum is reached. If less than 12 inches, replace pump. If vacuum reading is 12 inches or more, go to step 8. LIG H T T R U C K SERVIC E M A N U A L ENGINE 6-9 7. Check fuel lines and hoses for splits, leaks or kinks by disconnecting each section of line and connecting a vacuum gage. Crank or run engine until vacuum gage peaks. Vacuum should be at least 12 inches. If less, repair or replace defective line or hose as necessary. 8. If fuel pum p and fuel lines check O K , remove tank unit, replace strainer and clean fuel tank, if necessary. If carburetor is suspected, remove the air horn and check the following: a. Power Piston(s) or main fuel piston for freeness. b. D irt in jets and m etering passages. c. M etering rods. d. Power valve(s) or main fuel valve(s). e. Float adjustment. See C arburetor Cleaning Inspection and A djustm ent, Section 6C. K. H ard Starting - Cold (Engine Cranks O K ) 1. Visually check the following: a. Vacuum hoses for splits, kinks and proper connections. See hose routing charts, Section 6E. b. A ir leaks at carburetor m ounting and intake manifold. c. Ignition wires for cracking, hardness, proper connections, and carbon tracking. Repair or replace as necessary. d. Check choke and vacuum break operation and adjustm ent. 2. Check ignition timing per emission control inform ation label. “N on EST” if tim ing is too early - speed up engine to see if timing m ark moves If not, check for stuck mechanical advanace. Refer to Section 6D. Repair as necessary and recheck timing. Check EST if applicable Section 6D-6E. 3. Check the following: a. Choke, throttle linkage and fast idle cam for sticking. b. C arburetor flooding. Clean and repair as necessary. If repairs are necessary, see carburetor, cleaning and inspection, Section 6C. 4. Check ignition system - Section 6D. Check distributor for: a. W orn shaft b. Bare and shorted wires c. Repair or replace as necessary. 5. Remove spark plugs. Check for cracks, wear, im proper gap, burned electrodes, heavy deposits. Repair or replace as necessary. 6. Test fuel pump by connecting hose from carburetor fuel feed line to a suitable container. Start engine and let idle for 15 seconds. Pum p should supply 1/2 pint or more. If m ore than 1/2 pint, check filter in carburetor. Replace if necessary. If less than 1/2 pint, for mechanical pum p go to step 7. 7. Disconnect inlet hose at pum p and connect a vacuum gage. C rank or run engine LIG H T T R U C K SERVICE M A N U A L 6-10 ENGINE until maximum vacuum is reached. If less than 12 inches, replace pump. If more than 12 inches, go to step 8. 8. Check fuel lines and hoses for splits, leaks or kinks by disconnecting each section of line and connect vacuum gage. C rank or run engine until vacuum gage peaks. Vacuum should be at least 12 inches. If less, repair or replace defective line or hose. 9. If fuel lines and pump check O K, remove tank unit, replace strainer and clean fuel tank, if necessary. L. H ard Starting - Hot (Engine cranks O K ) 1. Visually check the following: a. Vacuum hoses for splits, kinks and proper connections. See hose routing Schematic, Vehicle Emission Control Inform ation Label. b. A ir leaks at carburetor m ounting and intake manifold. c. Ignition wires for cracking, hardness, proper connections, and carbon tracking. Repair or replace as necessary. 2. Check ignition timing per emission control information label. ’’Non E S T ” If timing is too early - speed up engine to see if timing m ark moves If not, check for stuck mechanical advance. Refer to Section 6D. Repair as necessary and recheck timing. Check EST if applicable see Section 6D. 3. Check the following: a. Choke, throttle linkage and fast idle cam for sticking. b. C arburetor flooding. Clean and repair as necessary. If repairs are necessary, see carburetor, cleaning and inspection, Section 6C. 4. Check ignition system Section 6D. Check distributor for: a. W orn shaft b. Bare and shorted wires c. Faulty pick up coil, module, ignition coil, and shorted condenser. Repair or replace as necessary. 5. Remove spark plugs. Check for cracks, wear, im proper gap, burned electrodes, heavy deposits. Repair or replace as necessary. 6. Also check steps 6, 7, 8, 9 - H ard Starting - Cold. Emission Non-Compliance, See Section 6E. ENGINE MECHANICAL DIAGNOSIS The following diagnostic information covers common problems and possible causes. When the proper diagnosis is made, the problem should be corrected by adjustment, repair or part replacement as required. Refer to the appropriate section of the manual for these procedures. CONDITION_________________POSSIBLE CAUSE___________ CORRECTION________________ Excessive Oil Loss LIG H T T R U C K SERVICE M A N U A L a. External oil leaks. 1. Tighten bolts a n d /o r replace gaskets and seals as necessary. b. Im proper reading of dipstick. 1. Check oil with car on a level surface and allow adequate drain down time. ENGINE Low Oil Pressure c. Im proper oil viscosity. 1. Use recommended S.A.E. viscosity for prevailing tem peratures. d. C ontinuous high speed driving a n d /o r severe usage such as trailer hauling. 1. C ontinuous high speed operation a n d /o r severe usage will normally cause decreased oil mileage. e. P.C.V. system m alfunctioning. 1. Service as necessary. f. Valve guides a n d /o r valve stem seals worn, or seals omitted. 1. Ream guides and install oversize service valves a n d /o r new valve stem seals. g. Piston rings not seated, broken or worn. 1. Allow adequate time for rings to seat. 2. Replace broken or worn rings as necessary. h. Piston im properly installed or misfitted. 1. Replace piston or repair as necessary. a. Slow idle speed 1. Set idle speed to spec. b. Incorrect or m alfunctioning oil pressure switch. 1. Replace with proper switch. c. Incorrect or malfunctioning oil pressure gage. 1. Replace with proper gage. d. Im proper oil viscosity or diluted oil. 1. Install oil of proper viscosity for expected tem perature. 2. Install new oil if diluted with m oisture or unburned fuel mixtures. e. Oil pum p worn or dirty. 1. Clean pum p and replace worn parts as necessary. f. Plugged oil filter. 1. Replace filter and oil. g. Oil pickup screen loose or plugged. 1. Clean or replace screen as necessary. h. Hole in oil pickup tube. 1. Replace tube. i. Excessive bearing clearance. 1. Replace as necessary. j. Cracked, porous or plugged oil galleys. 1. Repair or replace block. k. Galley plugs missing or misinstalled. 1. Install plugs or repair as necessary 6-11 LIG H T TR U C K SERVICE M A N U A L 6-12 ENGINE Valve Train Noise 1. Poor seal at timing cover gasket (231 engine only). 1. Replace gasket. a. Low oil pressure. 1. Repair as necessary. (See diagnosis for low oil pressure.) b. Loose rocker arm attachm ents. 1. Inspect and repair as necessary. c. W orn rocker arm a n d /o r pushrod. 1. Replace as necessary. d. Broken valve spring. 1. Replace spring. e. Sticking valves. 1. Free valves. f. Lifters worn, dirty or defective. 1. Clean, inspect, test and replace as necessary. g. Cam shaft worn or poor machining. 1. Replace camshaft. h. W orn valve guides. 1. Repair as necessary. ENGINE KNOCK DIAGNOSIS CONDITION POSSIBLE CAUSE CORRECTION a. Engine knocks cold and continues for two to three minutes. Knock increases with torque. 1. E FE equipped engines may have valve knock. 2. Flywheel contacting splash shield. 3. Loose or broken balancer or drive pulleys. 4. Excessive piston to bore clearance.1 1. Replace E FE valve. b. Engine has heavy knock hot with torque applied. LIG H T T R U C K SERVIC E M A N U A L 1. Broken balancer or pulley hub. 2. Loose torque converter bolts. 3. Accessory belts too tight or nicked. 4. Exhaust system grounded. 5. Flywheel cracked. 6. Excessive main bearing clearance. 7. Excessive rod bearing clearance. 2. Reposition splash shield. 3. Tighten or replace as necessary. 4. Replace piston. 1. Replace parts as necessary. 2. Tighten bolts. 3. Replace a n d /o r tension to specs as necessary. 4. Reposition as necessary. 5. Replace flywheel. 6. Replace as necessary. 7. Replace as necessary. ENGINE c. Engine has light knock hot in light load conditions. d. Engine knocks on initial start up but only lasts a few seconds. e. Engine knocks at idle hot. 1. D etonation or spark knock. 2. Loose torque converter bolts. 3. Exhaust leak at manifold. 4. Excessive rod bearing clearance. 1. Fuel pump. 2. Im proper oil viscosity. 3. H ydraulic lifter bleed dow n.2 4. Excessive crankshaft end clearance. 1. Loose or worn drive belts. ^ ^ 2. C om pressor or generator bearing. 3. Fuel pump. 4. Valve train. 5. Im proper oil viscosity. 6. Excessive piston pin clearance. 7. Connecting rod alignment. 8. Insufficient piston to bore clearance. 6-13 1. EST or ESC (See Section 6D or 6E) Check engine timing and fuel quality. 2. Tighten bolts. 3. Tighten bolts a n d /o r replace gasket. 4. Replace bearings as necessary. 1. Replace pump. 2. Install proper oil viscosity for expected temperatures. 3. Clean, test and replace as necessary. 4. Replace crankshaft thrust bearing. 1. Tension a n d /o r replace as necessary. 2. Replace as necessary. 3. Replace pump. 4. Replace parts as necessary. 5. Install proper viscosity oil for expected tem perature. 6. Ream and install oversize pins. 7. Check and replace rods as necessary. 8. Hone and fit new piston. ‘Cold engine piston knock usually disappears when the cylinder is grounded out. Cold engine piston knock which disappears in 1.5 minutes should be considered acceptable. 2W hen the engine is stopped, some valves will be open. Spring pressure against lifters will tend to bleed lifter down. A ttem pts to repair should be m ade only if the problem is consistent and appears each time engine is started. L IG H T T R U C K SERVICE M A N U A L 6-14 ENGINE DIESEL ENGINE DIAGNOSIS Diesel Engine Mechanical Diagnosis such as noisy lifters, rod bearings, main bearings, valves, rings and pistons is the same as for a gasoline engine. This diagnosis covers only those conditions that are different for the diesel engine. CONDITION Engine Will Not Crank Engine Cranks Slowly Will Not Start (Minimum Engine Cranking Speed 100 RPM COLD, 240 RPM HOT) Engine Cranks Normally — Will Not Start POSSIBLE CAUSE CORRECTION 1. Loose or Corroded Battery Cables Check connections at batteries, engine block and starter solenoid. 2. Discharged Batteries Check generator output and generator belt adjustm ent. 3. Starter Inoperative Check voltage to starter and starter solenoid. If OK, remove starter for repair. (Use diagnostic connector term inals shown on circuit drawing in ELECTRICAL DIAGNOSIS). 1. Battery Cable Connections Loose or Corroded Check connections at batteries, engine block and starter. 2. Batteries Undercharged Check charging system. 3. Wrong Engine Oil Drain and refill with oil o f recom m ended viscosity. 1. Incorrect Starting Procedure Use recom m ended starting procedure. 2. Glow Plugs Inoperative Refer to ELECTRICAL DIAGNOSIS. 3. Glow Plug Control System Inoperative Refer to ELECTRICAL DIAGNOSIS. 4. No Fuel Into Cylinders Remove any one glow plug. Depress the th ro ttle part way and crank the engine for 5 seconds. If no fuel vapors come out o f the glow plug hole, go to step 5. If fuel vapors are 4 noticed remove the rem ainder o f the glow plugs and see if fuel vapors come out o f each hole when the engine is cranked. If fuel comes out o f one glow plug hole only replace the injection nozzle in that cylinder. Crank the engine and check to see that fuel vapors are coming out o f all glow plug holes. If fuel is coming from each cylinder, go to step 11. 5. No Fuel To Injection Pump Loosen the line coming out o f the filter. Crank the engine, the fuel should spray out o f the fitting, use care to direct fuel away from sources o f ignition. If fuel sprays from the fitting go to step 10. 6. Restricted Fuel Filter Loosen the line going to the filter, if fuel sprays from the fitting, the filter is plugged and should be replaced. Use care to direct the fuel away from sources o f ignition. 7. Fuel Pump Inoperative Remove inlet hose to fuel pum p. Connect a hose to the pum p from a separate container that contains fuel. Loosen the line going to the filter. If fuel does not spray from the fitting, replace the pum p. Use care to direct the fuel away from source o f ignition. 8. Restricted Fuel Tank Filter Remove fuel tank and check filter. (Filter for diesel fuel is blue). Diesel Diagnosis 1 LIG H T T R U C K SERVIC E M A N U A L ENGINE 9. Plugged Fuel Return System Engine Cranks Normally Will Not Start (C ontd) Engine Starts But Will Not Continue To Run At Idle Disconnect fuel return line at injection pum p and route hose to a metal container. Connect a hose to the injection pum p connection, route it to the m etal container. Crank the engine. If it starts and runs, correct restriction in fuel return lines. If it does not start, remove the ball check connector from the top o f the injection pum p and make sure that it is not plugged. 10. No Voltage To Fuel Solenoid Connect a volt m eter to the wire at the injection pum p solenoid and ground. The voltage should be a m inimum o f 9 volts. If there is inadequate voltage, refer to the ELECTRICAL DIAGNOSIS for more inform ation. 11. Incorrect or Contam inated Fuel Flush fuel system and install correct fuel. 12. Pum p Timing Incorrect Make certain that pum p timing m ark is aligned with mark on adapter. 13. Low Compression Check compression to determ ine cause. 14. Injection Pump Malfunction Remove injection pum p for repair. 1. Slow Idle Incorrectly Adjusted Adjust idle screw to specification. 2. Fast Idle Solenoid Inoperative With engine cold, start engine;solenoid should move to hold injection pum p lever in “ fast idle position". If solenoid does not move, refer to ELECTRICAL DIAGNOSIS. 3. Restricted Fuel R eturn System Disconnect fuel return line at injection pum p and route hose to a metal container. Connect a hose to the injection pum p connection; route it to the metal container. Crank the engine and allow it to idle. If engine idles norm ally, correct restriction in fuel return line. If engine does not idle norm ally, remove the return line check valve fitting from the top o f the pum p and make sure it is not plugged. 4. Glow Plugs Turn O ff Too Soon Refer to ELECTRICAL DIAGNOSIS. 5. Pum p Timing Incorrect Make certain that tim ing m ark on injection pum p is aligned with m ark on adapter. 6. Limited Fuel To Injection Pump Test the engine fuel pum p, check for plugged filters; check fuel lines. Replace or repair as necessary. 7. Incorrect or C ontam inated Fuel Flush fuel system and install correct fuel. 8. Low Compression Check compression to determ ine cause. 9. Fuel Solenoid Closes In Run Position Ignition switch out o f adjustm ent. If OK, refer to ELECTRICAL DIAGNOSIS. Remove injection pum p for repair. 10. Injection Pump Malfunction Engine Starts, Idles Rough, WITHOUT Abnormal Noise or Smoke 6-15 1. Slow Idle Incorrectly Adjusted Adjust slow idle screw to specification. 2. Injection lin e Leaks Wipe o ff injection lines and connections. Run engine and check for leaks. Correct leaks. Diesel Diagnosis 2 LIG H T TR U C K SERVICE M AN U AL 6-16 j ENGINE 3. Restricted Fuel Return System Disconnect fuel return line at injection pum p and route hose to a metal container. Connect a hose to the injection pump connection; route it to the metal container. Start the engine and allow it to idle; if engine idles norm ally, correct restriction in fuel return lines. If engine does not idle norm ally, remove the return line check valve fitting from the top o f the pum p and make sure it is not plugged. 4. Air In System Install a section o f clear plastic tubing on the fuel return fitting from the engine. Evidence o f bubbles in fuel when cranking or running indicates the presence of an air leak in the suction fuel line. Locate and correct. 5. Inco rrecto r C ontam inated Fuel Flush fuel system and install correct fuel. 6. Nozzle(s) M alfunction Remove and clean or replace. 1. Injection Pump Timing Incorrect Be sure timing mark on injection pum p is aligned with mark on adapter. 2. Insufficient Engine Break-in Time Break-in engine 2000 or more miles. 3. Air in System Install a section o f clear plastic tubing on the fuel return fitting from the engine. Evidence o f bubbles in fuel when cranking or running indicates the presence o f an air leak in the suction fuel line. Locate and correct. 4. Nozzle(S) Malfunction Remove and clean or replace. 1. Plugged Fuel Filters Replace filters. 2. Incorrect Injection Pump Timing Be sure that timing m ark on injection pum p and adapter are aligned. 3. Incorrect or C ontam inated Fuel Flush fuel system and install correct fuel. 1. External Linkage Binding Or Misadjusted Free up linkage. Adjust or replace as required. 2. Fast Idle Malfunction Check fast idle adjustm ent. 3. Internal Injection Pump M alfunction Remove injection pum p for repair. 1. Loose or Broken Fuel Line or Connection Examine complete fuel system , including tank, and injection lines. Determine source and cause o f leak and repair. 2. Injection Pump Internal Seal Leak Remove injection pum p for repair. 1. Restricted Air Intake Check air cleaner elem ent. 2. EGR Malfunction Refer to Section 6E. 3. Restricted or Damaged Exhaust System Check system and replace as necessary. 4. Plugged Fuel Filter Replace filter. .".m ! r r j Engine Cold Starts and Idles Rough WITH Excessive Noise and/or Smoke But G ears Up After Warmup Engine Misfires Above Idle But Idles Correctly Engine Will Not Return To Idle Fuel Leaks On G round — No Engine Malfunction Noticeable Loss Of Power Diesel Diagnosis 3 LIG H T T R U C K SERVIC E M A N U A L ENGINE Noise - “Rap” From One or More Cylinders (Sounds Like Rod Bearing Knock) Excessive Black Smoke and/or Objectionable Overall Combustion Noise Engine Noise Internal Or External Engine Overheats 5. Plugged Fuel Tank V acuum Vent In Fuel Cap Remove fuel cap. If loud “hissing” noise is heard, vacuum vent in fuel cap is plugged. Replace cap. (Slight hissing sound is norm al). 6. R estricted Fuel Supply From Fuel Tank To Injection Pump Examine fuel supply system to determ ine cause o f restriction. Repair as required. 7. Restricted Fuel Tank Filter Remove fuel tank and check filter. (Filter for diesel fuel is blue). 8. Pinched or Otherwise Restricted Return System Examine system for restriction and correct as required. 9. Incorrect or Contam inated Fuel Flush fuel system and install correct fuel. 10. External Compression Leaks Check for com pression leaks at all nozzles and glow plugs, using “ Leak-Tec” or equivalent. If leak is found, tighten nozzle or glow plug. 11. Plugged Nozzle(s) Remove nozzles. Have them checked for plugging and repair or replace. 12. Low Compression Check compression to determ ine cause. 1. Nozzle(s) Sticking Open or with very low Nozzle Opening Pressure Remove nozzle for test and replace as necessary. 2. Mechanical Problem Refer to Mechanical Diagnosis Section 6A5. 1. Timing Not Set To Specification Make certain that tim ing m ark on injection pum p is aligned with m ark on adapter. 2. EGR Malfunction Refer to Emission Diagnosis. (Section 6E) 3. Injection Pump Housing Pressure Out Of Specifications Check housing pressure as described in Section 6A5. 4. Injection Pump Internal Problem Remove injection pum p for repair. 1. Engine Fuel Pump, G enerator, Water Pum p, Valve Train, Vacuum Pum p, Bearings, Etc. Repair or replace as necessary. If noise is internal, see Diagnosis For Noise - Rap From One or More Cylinders and Engine Starts and Idles Rough With Excessive Noise and/or Smoke. 1. Coolant System Leak, Oil Cooler System Leak or Coolant Recovery System Not Operating Check for leaks and correct as required. Check coolant recovery jar, hose and radiator cap. 2. Belt Slipping or Damaged Replace or adjust as required. 3. Therm ostat Stuck Closed Check and replace if required. 4. Head Gasket Leaking Check and repair as required. 6-17 Diesel Diagnosis 4 LIG H T T R U C K SERVICE M A N U A L 6-18 ENGINE Oil Warning Lamp “ ON” at Idle Engine Will Not Shut O ff With Key NOTE With engine at idle, pinch the fuel return line at the flexible hose to shut o ff engine. 1. Oil Cooler or Oil or Cooler Line Restricted Remove restriction in cooler or cooler line. 2. Oil Pum p Pressure Low See Section 6A5 for oil pum p repair procedures. 1. Injection Pump Fuel Solenoid Does Not Return Fuel Valve To “ O F F ” Position Refer to ELECTRICAL DIAGNOSIS. V A C U U M PU M P D IA G N O S IS Excessive noise or clattering noise. 1. Loose screws between pump assy, and drive assy. 1. A - Tighten screws to spec. B -R eplace “ 0 ” ring. C -R eplace pum p assy. 2. Loose tube on pum p assy. 2. Replace pum p assy. Hooting noise. Valves not functioning properly. Replace pum p assy. Pump assy, loose on drive assy. Stripped threads. Replace pum p assy. Oil around end plug. Loose plug. Oil leaking out crimp. Bad crimp. Install hose and vacuum gage to pum p, engine running, gage should have reading o f 20 inches vacuum m inim um . With engine off, vacuum level loss should not drop from 20 inches to 19 inches in less than 1-1/2 seconds. Replace pum p assy. 1. Defective valves. 2. Defective diaphragm. 3. Worn push rod seal. 4. Loose tube. Diesel Diagnosis 5 LIG H T T R U C K SERVIC E M A N U A L 1. Seat Plug. 2. Replace drive assy. Replace pum p assy. ENGINE 6-19 DIESEL ENGINE IDLE ROUGHNESS DIAGNOSIS PROCEDURE DIESEL ENGINE ROUGHNESS AT IDLE ON NEW C ARS - VEHICLE SHOULD HAVE 1/4 TANK FUEL & IT M AY BE NEC ESSA R Y TO RUN ENGINE AT HIGH RPM TO PURGE A IR FROM SYSTEM. REMOVE A IR CLEANER INSTALL COVER J-26996-1 INSTALL MAG-TACH J-26925 - CHECK IDLE SPEED (SLOW & FAST) __________________ I_____________ IDLE SPEED INCORRECT IDLE SPEEDS OK SET IDLE SPEED TO SPEC. (IF FAST IDLE WAS ADJUSTED. ADJUST HIGH VACUUM SWITCH. CALIF. T Y P E D CHECK T IM IN G M A RK ON INJECTION PUMP AND ADAPTER FOR ALIGNMENT I _____________________________________ ___________________________________ T IM IN G OFF T IM IN G OK I ALIGN M A R K S DISCONNECT VACUUM HOSE FROM VACUUM PUMP - CHECK IDLE QUALITY IDLE IMPROVES NO IMPROVEMENT REINSTALL VACUUM HOSE TO PUMP. LOOSEN VACUUM PUM P HOLD DOWN CLAMP. ROTATE PUM P IN ENGINE. IF IDLE IMPROVES, CLAMP IN THAT POSITION. IF IDLE DOES NOT IMPROVE, REMOVE VACUUM PUMP AND REINSTALL WITH DR IV E GEAR IN DIFFERENT RELATIONSHIP TO CAMSHAFT. --------- — I EXAM INE NOZZLES FOR LEAKS AT NOZZLE BODY OR AT FUEL LINE CONNECTION. (ENGINE RUNNING) I LEAKS NO LEAKS CORRECT CHECK FOR LEAK AT INJECTION PUM P TO HIGH PRESSURE LIN ES I LEAKS NO LEAKS CORRECT CHECK FOR FUEL PRESSURE BY C RA CK IN G LINE AT FITTING BETWEEN FUEL FILTER AND INJECTION PUMP PRESSURE EVIDENT NO PRESSUR: EVIDENT DETERMINE CAUSE OF LACK nr'O R | ppr;<;iipr CONTINUE ON NEXT PAGE Diesel Diagnosis 6 L IG H T T R U C K SERVIC E M AN U AL 6-20 ENGINE REMOVE FUEL RETURN LINE FROM TOP OF PUMP. INSTALL SHORT PIE C E S OF CLEAR P L A S T IC TUBE BETWEEN RETURN LINE AND CHECK FOR PRESENCE OF BUBBLES OR FOAM IN TUBE. NO BU BBLES OR FOAM BU BBLES EVIDENT F IN D C A U SE IN FUEL SU P PLY LOOSEN THE LINE AT THE NOZZLES TO BLEED A SM ALL AMOUNT OF FUEL FROM THE L IN E IF S O L ID FUEL APPEARS, GO ON TO THE NEXT NOZZLE. IF FOAM A P P E A R S SHUT THE ENGINE OFF AND DISCONNECT THE LINE FROM THE N O Z ZLE MOVE THE LINE SO THE INLET TO THE NOZZLE CAN BE OBSERVED. REMOVE THE P IN K W IRE TO THE PU M P AND CRANK THE ENGINE AND O BSERVE THE NOZZLE INLET FOR BUBBLES. IF BUBBLES ARE EVIDENT, REPLACE THE N O Z ZLE S Q U IR T SOME O IL OR FUEL IN THE NEW NOZZLE INLET AND RECHECK FOR BUBBLES. IF BU BBLES ARE NOT EVIDENT RECONNECT THE LINE AND P IN K W IR E AND GO ON TO THE NEXT NOZZLE AND REPEAT THE PROCESS. CHECK THE REMOVED NOZZLE ON A TESTER TO DETERMINE IF IT IS INOPERATIVE OR IF IT IS IN C O M PA T IB LE WITH THE C YLIN D ER HEAD. IF AN OBJECTIONABLE ROUGH IDLE CO N D IT IO N STILL EXIST S, PROCEED U S IN G GLOW PLUG R E SIST A N C E CHECK TO CORRECT ROUGH IDLE Diesel Diagnosis 7 LIG H T T R U C K SERVIC E M A N U A L IN-LINE 6 6A1-1 Valves.............................................................................. Torsional D am per.......... ............ ................................. C rankcase Front C o v e r.............................................. Oil Seal (Front C o v er)............................................... C a m s h a ft....................................................................... C am shaft B earings...................................................... Oil P a n .......................... ................................................. Oil Pum p........................................................................ Engine Bearings............................................................ Oil Seal (R ear M a in )................................................. Piston and Connecting Rod A ssem blies................ Flyw heel.......................................................................... Engine A ssem bly.......................................................... C ra n k sh a ft..................................................................... Specifications................................................................... 6A1-16 6A1-16 6A1-16 6A1-17 6A1-17 6A1-18 6A1-19 6A1-19 6A1-20 6A1-24 6A1-25 6A1-28 6A1-29 6A1-30 6A1-32 Section 6A1 Contents 4.1 L (D) L-6 - RPO LE3 4.8 L (T) L-6 - RPO L25 G eneral D escription....................................................... 6A1-1 Engine L ubrication........................................................ 6A1-2 On Vehicle Service........................................................ 6A1-9 Engine M o u n ts.................. ...........................................6A1-9 M anifold A ssem bly-N on-Integrated H e a d .......... .6A1-10 Exhaust M anifold-Integrated H e a d ........................6A1-10 Rocker A rm C o v er......................... ............................ .6 A 1-11 Push Rod Side C o v e r...................................................6 A 1-11 Valve M echanism ........................................................ .6A1-11 Valve Stem Oil Seal an d /o r Valve S p rin g .............6A 1-11 Valve L ifte rs................................................................. .6A1-12 C ylinder H e a d ...............................................................6A1-14 Rocker A rm S tud s....................................................... .6A1-15 Valve G uides................................................................. .6A1-15 Valve S e a ts .....................................................................6A1-16 :br GENERAL DESCRIPTION CYLINDER BLOCK The cylinder block is m ade of cast iron and has 6 cylinders arranged "In -L in e". Seven main bearings support the crankshaft which is retained by recessed bearing caps th at are m achined with the block for proper alignm ent and clearances. Cylinders are completely encircled by coolant jackets. CYLINDER HEAD The cast iron cylinder head has individual intake and exhaust ports for each cylinder. Valve guides are integral and rocker arm s are retained on individual threaded studs pressed into head. The 4.1 L(D ) heads have integrated inlet manifolds. The 4.8 L(T) uses separate inlet manifolds. CRANKSHAFT AND BEARINGS The crankshaft is cast nodular iron and is supported by seven main bearings. N um ber seven bearing is the end thrust bearing. M ain bearings are lubricated from oil holes which intersect the main oil gallery located on the right side of the block. The cam bearings are also fed oil by intersect­ ing holes with main oil gallery. The lifters are located in the m ain oil gallery. A dam per assembly, on the forward end of the crank­ shaft, dampens any engine torsional vibrations. The outer ring of the dam per is grooved for the accessory drive belts. CAMSHAFT AND DRIVE The cast iron cam shaft is supported by four bearings and is gear driven. A cast iron crankshaft gear drives the alum inum cam shaft gear. Cam lobes are ground, hardened and tap ered w ith the high side tow ard the rear. This, coupled with a spherical face on the lifters, causes the valve lifters to rotate. PISTONS AND CONNECTING RODS The pistons are m ade of a cast alum inum alloy using two compression rings and one oil control ring. Piston pins in the 4.1 L (D) engine are offset .060" (1.5m m ) toward the th ru st side (right hand side) to provide a gradual change in th ru st pressure against the cylinder wall as the piston travels its path. This also provides for quieter operation. 4.8 L (T ) engine piston pins are on piston centerline for best durability and reduced friction. Pins are chrom ium steel and have a floating fit in the pistons. They are retained in the connecting rods by a press fit. Connecting rods are made of forged steel. Full pressure lubrication is directed to the connecting rods by drilled oil passages from the adjacent main bearing journal. Oil holes at the connecting rod journals are located so that oil is supplied to give m axim um lubrication just prior to full bearing load. VALVE TRAIN A very simple ball pivot-type train is used. M otion is transm itted from the cam shaft through the hydraulic lifters and push rods to the rocker arms. The rocker arm pivots on its ball and transm its the cam shaft motion to the valve. The rocker arm ball is retained by a self locking nut. HYDRAULIC VALVE LIFTERS H ydraulic Valve Lifters are used to keep all parts of the valve train in constant contact for quiet operation. L IG H T T R U C K SERVICE M A N U A L 6A1-2 IN-LINE 6 The hydraulic lifter assembly consists of: the lifter body, which rides in the cylinder block boss, a plunger, a push rod seat, a m etering valve, a plunger spring, a check ball and spring, a check ball retainer and a push rod seat retainer. W hen the lifter is riding on the low point (base circle) of the cam , the plunger spring keeps the plunger and push rod seat in contact with the push rod. W hen the lifter body begins to ride up the cam lobe, the check ball traps the oil in the reservoir below the plunger. The plunger and lifter body then rise as a unit, pushing up the push rod and opening the valve. A very small am ount of oil will leak out between the plunger and the body. As the lifter body rides down the other side of the cam, the plunger follows with it until the valve closes. The lifter body continues to follow the cam to its low point, but the plunger spring keeps the plunger in contact with the push rod. The ball check valve will then move off its seat and the lifter reservoir will be refilled with oil. INTAKE MANIFOLD The intake manifold is of cast iron, single level design for efficient fuel distribution. The 4.1 L (D) manifold is an integral unit with the head on all vehicles. 4.8 L (T) engines use separate components. The carburetor pad is centrally located w ith an early fuel evaporation (E F E ) passage running underneath the pad, through which exhaust gases are forced, to promote faster fuel vaporization when the engine is cold. An exhaust gas recirculation port is also cast into the manifold on 4.1 L (D ) engines, for the induction of a m etered am ount of exhaust gases into the air and fuel m ixture which has entered through the carburetor. EXHAUST MANIFOLD On 4.8 L (T) engines a single four port, underslung, center take down manifold of cast ironl is used to direct exhaust gases from the com bustion cham bers. On 4.1 L (D) engines a single four port, underslung, dual center take down manifold of cast iron is used. A heat shield is m ounted to the manifold th a t is used to route heated air to the air cleaner for better fuel vaporization. Engine Lubrication Full pressure lubrication, through a full flow oil filter is furnished by a gear-type oil pump. The distributor, driven by a helical gear on the cam shaft, drives the oil pump. Oil draw n by the pick-up screen and pipe is pressurized in the pum p and routed to the oil filter. If excessive backpressure is encountered at the filter, a bypass valve allows oil flow to the m ain oil gallery, located along the right side of the block. This rifle drilled gallery supplies oil to the cam shaft bearings, the hydraulic lifters and the crankshaft main bearings. LIG H T T R U C K SERVICE M A N U A L The connecting rod bearings are supplied oil from the c ran k sh a ft m ain bearings by m eans of cross drilled passages. The valve train is supplied its lubrication from the valve lifters. Oil within the lifters is pum ped up through the top of the lifters through the hollow push rods to the rocker arms. From the head, oil is drained back to the crankcase through oil drain back holes and the push rod holes. (Fig. 6A1-1). IN-LINE 6 6A1-3 OIL PRESSURE SENDING UNIT Fig. 6 A 1-1--In-Line Engine Lubrication LIG H T T R U C K SERVIC E M AN U AL 6A1-4 IN-LINE 6 LIG H T T R U C K SERVIC E M A N U A L IN-LINE 6 6A1-5 FOUR-SPEED MANUAL WITH PROP SHAFT BRAKE Fig. 6 A l - 3 - - " P " Series - Engine Rear M o u n t Fig. 6 A l- 4 - - " C " Series - Engine Rear Mounts L IG H T TR U C K SERVIC E M AN U AL 6A1-6 IN-LINE 6 250 CU. IN. ENGINE LEFT & RIGHT MOUNT & FRAME BRACKET 292 CU. IN. ENGINE LEFT MOUNT & FRAME BRACKET VIEW ENGINE BRACKET ALL C SERIES WITH L-6 ENGINE 292 CU. IN. ENGINE RIGHT FRAME BRACKET & MOUNT VIEW Fig. 6 A l- 5 - - " C " Series - Engine Front M ount LIG H T T R U C K SERVICE M A N U A L A L ENGINE MOUNT & BRACKET ALL K SERIES WITH L-6 ENGINE Z........... 7 VIEW A \ FWD X 292 CU. IN. R. SIDE ENGINE M O U N T FRAME BRACKET ALL K SERIES WITH L-6 ENGINE 6A1-8 IN-LINE 6 LIG H T T R U C K SERVICE M A N U A L IN-LINE 6 6A1-9 M AR MOUNT FRONT MOUNT Fig. 6 A 1 -8 --" G " Series - Engine Mounts ON VEHICLE SERVICE ENGINE MOUNTS Engine mounts (Fig. 6A1-2 - 6A 1-8) are the nonad ju sta b le type and seldom req u ire service. Broken or d e te rio ra ted m ounts should be replaced im m ediately, because of the added strain placed on other m ounts and drive line components. Checking Engine Mounts Front Mount Raise the engine to remove weight from the m ounts and to place a slight tension in the rubber. Observe both mounts while raising engine. If an engine m ount exhibits: a. H ard rubber surface covered with heat check cracks; b. R ubber separated from a m etal plate of the mount; c. R ubber split through center, replace the m ount. If th e re is relative m ovem ent between a m etal plate of the m ount and its attaching points, lower the engine on the m ounts and tighten the screws or nuts attaching the m ount to the engine, frame, or bracket. Rear Mount Raise the vehicle on a hoist. Push up and pull down on the transm ission tailshaft while observing the transm ission m ount. If the rubber separates from the metal plate of the m ount or if the tailsahft moves up but not down (m ount bottom ed out) replace the m ount. If there is relative movement between a m etal plate of the m ount and its attaching point, tighten the screws or nuts attaching the m ount to the transm ission or crossmember. Front Mount Replacement 1. Remove engine m ount through bolt. 2. R aise engine and remove m ount to fram e bracket atta c h in g bolts. Remove m ount. R aise engine only enough for sufficient clearance. Check for interference between rear of engine and cowl panel. LIG H T T R U C K SERVICE M A N U A L 6A 1-10 IN-LINE 6 3. Install new engine m ount to fram e bracket and torque attaching bolts to specifications. 4. Install engine m ount through bolt and torque to 30 lb. ft. (40 N-m) specifications. Rear Mount Replacement 1. Support engine weight to relieve rear mounts. 2. Remove crossm em ber-to-m ount bolts. 3. On " P " Series with m anual transm ission and propeller shaft parking brake, remove mount attaching bolts from fram e outrigger and clutch housing and remove rear mounting cushions. 4. Rem ove m ount-to-tran sm issio n bolts, then remove mount. 5. On "P " Series with m anual transm ission and propeller shaft parking brake, install new mounting cushions and bolts. 6. Install new m ount on transm ission. 7. W hile lowering transm ission, align and sta rt crossm em ber-to-m ount bolts. 8. Torque bolts to 45 lb. ft. (60 N-m ) then bend lock tabs to bolt head as applicable. MANIFOLD ASSEMBLY - NON-INTEGRATED HEAD Removal 1. Disconnect battery negative cable at battery. 2. Remove air cleaner. 3. D isconnect both th ro ttle controls at bellcrank and remove throttle retu rn spring. 4. Disconnect fuel and vacuum lines at carburetor. 5. Disconnect crankcase ventilation hose at rocker arm cover. 6. Disconnect vapor hose at canister. 7. Disconnect exhaust pipe at m anifold flange. 8. Remove m anifold a tta c h in g bolts and clam ps then remove m anifold assembly. 9. Check for cracks in manifold castings. 10. Separate manifolds by removing one bolt and two nuts at center of assembly. 11. Observe gaskets and packing if necessary to diagnose a leakage problem. Installation 1. Clean gasket surfaces on cylinder head and manifolds. 2. Lay a straight edge along the full length of the exhaust port faces and m easure any gaps between the straight edge and the port faces. If at any point a gap of .030" (.80m m) or more exists, it is likely th at the m anifold has distorted to a point where it will not seat properly. If a good exhaust seal is to be expected, the exhaust manifold must be replaced. 3. Assem ble intake and exhaust manifolds using a new gasket by reinstalling the one bolt and two nuts at the center of the manifold to finger tight. 4. Position a new gasket over m anifold end studs on the cylinder head. 5. Install manifold assembly bolts, clamps and washers while holding manifold assembly in place by hand. LIG H T T R U C K SERVIC E M A N U A L 6. Clean, oil and torque all manifold assembly to cylinder head bolts and nuts to 40 lbs. ft. (55 N-m). 7. Com plete torquing the inlet to exhaust manifold bolt and two nuts at the center of the manifold to 45 lb. ft. (61 N-m). 8. Connect exhaust pipe to manifold using a new packing. 9. C onnect crankcase ventilation hose at rocker arm cover. 10. Connect vapor hoses at canister. 11. Connect fuel and vacuum lines a carburetor. 12. C onnect th ro ttle controls at bellcrank and install throttle return spring. 13. Install air cleaner, start engine, check for leaks and adjust carburetor idle speed. EXHAUST MANIFOLD ASSEMBLY - INTEGRATED HEAD Removal 1. Disconnect negative battery cable. 2. Remove air cleaner. 3. Remove power steering pum p a n d /o r A .I.R . pum p brackets, if so equipped. 4. Remove P A IR pipes as outlined in Section 6E. 5. Raise vehicle on hoist and disconnect exhaust pipe at manifold and converter bracket at transmission mount. 6. Lower vehicle. 7. Remove exhaust manifold bolts. 8. Remove exhaust manifold, check EFE Valve to see if free and check manifold for cracks. Installation If a new exhaust manifold is being installed, the E.F.E. valve and actuator and rod assembly m ust be transferred from the old component. 1. C lean gasket surface and position new gasket on exhaust manifold. 2. Install manifold bolts, while holding manifold assembly in place. 3. Torque all manifold to cylinder head bolts in sequence to torques shown in figure 6 A 1-9. 4. Raise vehicle on hoist. 5. Connect exhaust pipe at manifold flange and converter bracket at transm ission mount. A ttach exhaust pipe and align exhaust system. Torque attaching bolts to specification. / 12W w ^ 1 8 -2 5 — ( 5 } ft. lbs w & _ ex. 3 5 -4 0 n 't T'vrcue rear main bearing cap to 10- TC 41 ( 1 4 N ■ I tap end of crankshaft, first rearw ard then forward with a lead ham m er. This will line up rear main bearing id - 1 thrust surfaces. Retorque all main bearing ' ' !b. ft. (88N -m ). I mWT TDI IPK q p-pv/ irr 6A1-24 IN-LINE 6 .0 0 4 S H IM STOCK 1 1 /6 4 Fig. 6A1-34--Oil Seal Installation Tool Fig. 6 A 1-37--Crankshaft Oil Seal - Rear Main APPLY SEALANT TO SHADED AREAS ONLY Fig. 6Al-35--Removing Oil Seal Lower Half - Typical Fig. 6Al-38--Sealing Bearing Cap - Typical 1. W ith the oil pan and oil pum p removed, remove the rear main bearing cap. 2. Remove oil seal from the bearing cap by prying from the bottom with a small screw driver (fig. 6 A 1-35). 3. Use a small ham m er to tap a brass pin punch on one end of the upper seal until it protrudes far enough to be removed with pliers (fig. 6 A 1-36). 4. Clean all sealant and foreign m aterial from cylinder case bearing cap and crankshaft, using a nonabrasive cleaner. Fig. 6Al-36--Removing Oil Seal Upper Half - Typical OIL SEAL (REAR MAIN) 5. Inspect com ponents for nicks, scratches, b u rrs and m achining defects at all sealing surfaces, case assembly and crankshaft. 6. C oat seal lips and seal bead with light engine oil - keep oil off seal m ating ends. Replacement 7. Position tip of tool between crankshaft and seal seat in cylinder case. The rear main bearing oil seal can be replaced (both halves) w ithout removal of the crankshaft. Always replace the upper and lower seal as a unit. Install seal with lip facing front of engine. Extrem e care should be exercised when installing this seal to protect the sealing bead located in the channel on the outside diam eter of the seal. An installation tool (fig. 6A1-34) can be used to protect the seal bead when positioning seal as follows: 8. Position seal between crankshaft and tip of tool so that seal bead contacts tip of tool. M ake sure *hat oil-seal lip is positioned toward front of engine (fig. 6 A 1-37). 9. Roll seal around crankshaft using tool as a "shoe­ horn" to protect seal bead from sharp corner of seal seat surface in cylinder case. Installation tool must remain in position until seal is properly positioned with both ends flush with block. IN-LINE 6 6A1-25 10. Remove tool, being careful not to w ithdraw seal. 11. Install seal half in bearing cap, again using tool as a "shoe-horn", feeding seal into cap using light pressure with thum b and finger. PRESS 12. Install bearing cap to case with sealant applied to the cap-to-case interface being careful to keep sealant off the seal split line (fig. 6A1-38). 13. Install the rear main bearing cap (with new seal) and torque to 10-12 lb. ft. (14-16 N -m ). T ap end of crankshaft first rearw ard then forward with a lead ham m er. This will line up re a r m ain bearing and crankshaft thrust surfaces. R etorque bearing cap to 65 lb. ft. (88N-m ). -PISTON PIN REMOVER J -2 4 0 8 6 -8 PISTON AND CONNECTING ROD ASSEMBLIES Removal 1. Remove oil pan, oil pump and cylinder head as pre­ viously outlined. FIXTURE & SUPPORT ASSEMBLY J -2 4 0 8 6 -2 0 2. For the cylinder being serviced, turn crankshaft until piston is at the bottom of the stroke. Place a cloth on top of the piston. 3. Use a ridge ream er to remove any ridge an d /o r deposits from the upper end of the cylinder bore. 4. T urn crankshaft until piston is a t top of stroke and remove cloth and cuttings. 5. Remove connecting rod cap and install Tool J-6305 (1 1 /3 2 ") on studs. Push connecting rod and piston assem bly out of top of cylinder block (fig. 6A1-39). It will be necessary to turn the crankshaft slightly to disconnect some of the connecting rod and piston assemblies and push them out of the cylinder. Fig. 6A1-40--Removing Piston Pin Disassembly 1. Remove connecting rod bearings from connecting rods and caps. If bearings are being reused, place them in a rack so they m ay be reinstalled in th e ir original positions. 2. Remove piston rings by expanding and sliding them off the pistons. Tools J-8021 (3 -7 /8 ") and J-22249 (3-15/ 16") are available for this purpose. 3. Place connecting rod and piston assem bly on tool J-24086-20. U sing an arbor press and piston pin remover, J-24086-8, press the piston pin out of connect­ ing rod and piston (fig. 6 A 1-40). Cleaning and Inspection Connecting Rods W ash connecting rods in cleaning solvent and dry with compressed air. Check for twisted or bent rods and inspect for nicks or cracks. Replace connecting rods th at are damaged. Pistons Fig. 6Al-39--Removing Connecting Rod & Piston Assembly C lean varnish from piston skirts and pins w ith a cleaning solvent. DO N O T W IR E BRU SH A N Y PA R T O F T H E PIS T O N . Clean the ring grooves with a groove cleaner and make sure oil ring holes and slots are clean. Inspect the piston for cracked ring lands, skirts or pin bosses, wavy or worn ring lands, scuffed or dam aged skirts, eroded areas at top of the piston. Replace pistons that are dam aged or show signs of excessive wear. Inspect the grooves for nicks or burrs that might cause the rings to hang up. M easure piston skirt (across center line of piston pin) and check clearance. LIGHT TRUCK SERVICE MANUAL 6A1-26 IN-LINE 6 Piston Pins Piston Rings The piston pin clearan ce is designed to m aintain adequate clearance under all engine operating conditions. Because of this, the piston and piston pin are a m atched set and not serviced separately. All compression rings are m arked on the upper side of the ring. W hen installing compression rings, make sure the m arked side is toward the top of the piston. The top ring is chrom e faced, or treated with molybdenum for m axim um life. The oil control rings are of three piece type, consisting of two segments (rails) and a spacer. 1. Select rings com parable in size to the piston being used. 2. Slip the compression ring in the cylinder bore; then press the ring down into the cylinder bore about 1/4" (6.5m m ) (above ring travel). Be sure ring is square with cylinder wall. 3. M easure the space or gap between the ends of the ring with a feeler gage. 4. If the gap betw een th e ends of the ring is below specifications, remove the ring and try another for fit. 5. Fit each compression ring to the cylinder in which it is going to be used. 6. If the pistons have not been cleaned and inspected as previously outlined, do so. 7. Slip the outer surface of the top and second com pres­ sion ring into the respective piston ring groove and roll the ring entirely around the groove to make sure that the ring is free. If binding occurs at any point the cause should be determ ined, and if caused by ring groove, remove by dressing with a fine cut file. If the binding is caused by a distorted ring, check a new ring. 8. Install piston rings as follows (fig. 6A1-42): a. Install oil ring spacer in groove and insert an ti­ rotation tang in oil hole. b. Hold spacer ends butted and install lower steel oil ring rail with gap properly located. Inspect piston pin bores and piston pins for wear. Piston pin bores and piston pins m ust be free of varnish or scuffing when being m easured. The piston pin should be measured with a m icrom eter and th e piston pin bore should be measured with a dial bore gage or an inside m icrom eter. If clearance is in excess of the .001 " wear limit, the piston and piston pin assembly should be replaced. ASSEMBLY 1. Lubricate piston pin holes in piston and connecting rod to facilitate installation of pin. 2. Place connecting rod in piston and hold in place with piston pin guide and piston pin. Place connecting rod and piston assem bly on fixture and support assembly. 3. Using piston pin installer, J-24086-9, press the piston pin into the piston and connecting rod (Fig. 6A1-41). M ake sure in staller is set properly (see tool instructions). NOTICE: A fter installer hub bottoms on support assem ­ bly, do not exceed 5000 psi pressure, as this could cause structural dam age to the tool. 4. Remove piston and connecting rod assembly from tool and check piston for freedom of movement on piston pin. PRESS PISTON PIN INSTALLER J -2 4 0 8 6 -9 PISTON PIN c. Install upper steel oil ring rail with gap properly located. d. Flex the oil ring assembly to m ake sure ring is free. If binding occurs at any point, the cause should be determ ined, and if caused by ring groove, remove by dressing groove with a fine cut file. If binding is caused by a distorted ring, check a new ring. e. Install second compression ring expander then ring with gaps properly located. f. Install top com pression ring w ith gap properly located. 9. Proper clearance of the piston ring in its piston ring groove is very im portant to provide proper ring action and reduce wear. Therefore, when fitting new rings, the clearances between the surfaces of the ring groove should be m easured (fig. 6A 1-43). (See Specifications.) Installation C ylinder bores must be clean before piston installation. This may be accomplished with a hot w ater and detergent wash or with a light honing as necessary. A fter cleaning, the bores should be swabbed several tim es with light engine oil and a clean dry cloth. Fig. 6 A 1-41--Installing Piston Pin LIGHT TRUCK SERVICE MANUAL 1. L ubricate connecting rod bearings and install in rods and rod caps. IN-LINE 6 ENGINE LEFT ENGINE FRONT 6A1-27 ENGINE RIGHT INSERT PISTONS WITH NOTCHES TOWARD FRONT OF ENGINES FRONT OF ENGINE A " O IL R IN G SPACER G A P Fig. 6Al-44--Pistons-lnstalled Position B" O IL R IN G RAIL G A P S “C" 2N D C O M P R E S S IO N 'D ' 1 TO P C O M P R E S S IO N R IN G R IN G GAP GAP Fig. 6Al-42--Ring Gap Location Fig. 6A1-45--lnstalling Connecting Rod and Piston Assembly Fig. 6Al-43--Measuring Ring Groove Clearance 2. Lightly coat pistons, rings and cylinder walls with light engine oil. 3. W ith bearing caps removed, install Tool J-6305 (11/ 32 ") on connecting rod bolts. 4. Install each connecting rod and piston in its respective bore. Pistons m ust have notches facing front of engine (fig. 6 A 1-44). Use Tool J-8037 to compress the rings (fig. 6A1-45). Guide the connecting rod into place on the crankshaft journal with Tool J-6305 (1 1 /3 2 "). Use a ham m er handle and light blows to install the piston into the bore. H old the ring com pressor firmly ag ain st the cylinder block until all piston rings have entered the cylinder bore. 5. Remove J-6305. 6. Install the bearing caps and torque nuts to 35 lb. ft. (47N-m ). CYLINDER BLOCK Cleaning and Inspection 1. W ash cylinder block thoroughly in cleaning solvent and clean all sealing surfaces. LIGHT TRUCK SERVICE MANUAL 6A1-28 IN-LINE 6 2. Remove oil gallery plugs and clean all oil passages. 3. Clean and inspect w ater passages in the cylinder block. 4. Inspect the cylinder block for cracks in the cylinder walls, w ater jacket, valve lifter bores and main bearing webs. 5. M easure the cylinder walls for taper, out-of-round or excessive ridge at top of ring travel. This should be done with a dial indicator. Set the gage so th at the thrust pin must be forced in about 1/4" (6.5m m ) to enter gage in cylinder bore. C enter gage in cylinder and turn dial to " O " . Carefully work gage up and down cylinder to determ ine taper and turn it to different points around cylinder wall to determ ine the out-of-round condition. If cylinders were found to exceed specifications, honing or boring will be necessary. Conditioning The perform ance of the following operation is contin­ gent upon engine condition at tim e of repair. If the cylinder block inspection indicated th at the block was suitable for continued use except for out-of-round or tapered cylinders, they can be conditioned by honing or boring. If the cylinders were found to have less than .005" taper or wear they can be conditioned with a hone and fitted with the high limit standard size piston. A cylinder bore of less then .005 " wear or taper may not entirely clean up when fitted to a high limit piston. If it is desired to entirely clean up the bore in these cases, it will be necessary to rebore for an oversize piston. If m ore than .005" taper or wear, they should be bored and honed to the sm allest oversize th at will perm it complete resurfacing of all cylinders. W hen pistons are being fitted and honing is not necessary, cylinder bores may be cleaned with a hot water and d eterg en t w ash. A fter cleaning, the cylinder bores should be swabbed several times with light engine oil and a clean cloth and then wiped with a clean dry cloth. Boring 1. Before using any type boring b ar, th e top of the cylinder block should be filed to remove any dirt or burrs. This is very im portant. If not checked, the boring bar may be tilted which would result in the rebored cylinder wall not being a t rig h t angles to the crankshaft. 2. The piston to be fitted should be m easured with a m icrom eter, m easuring at the center of the piston skirt and at right angles to the piston pin. The cylinder should be bored to the sam e diam eter as the piston and honed to give the specified clearance. 3. The instructions furnished by the m anufacturer of the equipm ent being used should be carefully followed. Honing 1. W hen cylinders are to be honed follow the hone m anufacturer’s recom m endations for the use of the hone and cleaning and lubrication during honing. 2. Occasionally during the honing operation, the cylinder bore should be th oroughly cleaned and th e piston selected for the individual cylinder checked for correct fit. 3. W hen finish honing a cylinder bore to fit a piston, the hone should be moved up and down at a sufficient speed LIGHT TRUCK SERVICE MANUAL to obtain very fine uniform surface finish m arks in a cross-hatch pattern of approxim ately 45 to 65° in­ cluded angle. The finish m arks should be clean but not sharp, free from imbedded particles and torn or folded m etal. 4. Perm anently m ark the piston for the cylinder to which it has been fitted and proceed to hone cylinders and fit the rem aining pistons. NOTICE: H andle the pistons with care and do not attem pt to force them through the cylinder until the cylinder has been honed to correct size as this type piston can be distorted through careless handling. 5. Thoroughly clean the bores with hot w ater and deter­ gent. Scrub well with a stiff bristle brush and rinse thoroughly with hot w ater. It is extrem ely essential that a good cleaning operation be perform ed. If any of the abrasive m aterial is allowed to rem ain in the cylinder bores, it will rapidly wear the new rings and cylinder bores in addition to the bearings lubricated by the contam inated oil. The bores should be swabbed several times with light engine oil and a clean cloth and then wiped with a clean dry cloth. Cylinders should not be cleaned with kerosene or gasoline. Clean the rem ainder of the cylinder block to remove the excess m aterial spread during the honing operation. PISTON SELECTION 1. C heck U SE D piston to cylinder bore clearance as follows: a. M easure the "C y lin d er Bore D iam eter" w ith a telescope gage (2 -1 /2 " (64m m ) from top of cylinder bore). b. M easure the "P iston D ia m e te r" (a t skirt across center line of piston pin). c. S ubtract piston diam eter from cylinder bore diam e­ ter to determ ine " Piston to Bore C learance ". d. D eterm ine if piston to bore clearance is in the acceptable range. 2. If used piston is not acceptable, determ ine if a new piston can be fitted to the cylinder bore. 3. If cylinder bore must be reconditioned, m easure new piston diam eter (across center line of piston pin) then hone cylinder bore to correct clearance. 4. M ark the piston to identify the cylinder for which it was fitted. FLYWHEEL Removal All Except L25 Engines 1. Remove transmission an d /o r clutch housing and clutch from engine. 2. Remove flywheel retaining bolts and remove flywheel. L25 Engines 1. Remove transmission an d /o r clutch housing and clutch from engine. 2. M ark relationship of flywheel and crankshaft so th at dowel holes can be aligned in their original positions on assembly. 3. Remove engine oil pan and rear main bearing cap. IN-LINE 6 4. Remove flywheel retaining bolts and drive crankshaft dowels out of flywheel and crankshaft. R otate crank­ shaft as necessary so dowels clear cylinder block. 5. Remove flywheel and discard used dowel pins. Repair Only repair recom m ended at flywheel used with con­ ventional clutch is replacem ent of starter gear in event gear is worn or otherwise dam aged. Use torch to heat the gear around entire circum ference, then drive the gear off flywheel, using care not to dam age the flywheel. U niform ly heat the flywheel gear to tem perature which will expand gear to perm it installation. [T em perature must not exceed 400°F (204° C )|. As soon as gear has been heated, install on flywheel. NOTICE: NEVER HEAT STARTER GEAR TO RED HEAT AS TH IS W ILL CHANGE METAL STRUCTURE. Installation All Except L25 Engines 1. Clean the mating surfaces of flywheel and crankshaft to m ake certain there are no burrs. 2. Install flywheel on crankshaft and position to align dowel hole of crankshaft flange and flywheel. 3. Install flywheel retain in g bolts and torque to specifications. L25 Engine 1. Clean the mating surfaces of flywheel and crankshaft to m ake certain there are no burrs. 2. Install flywheel on crankshaft and position to align dowel holes of crankshaft flange and flywheel. 3. In stall flywheel retain in g bolts and torque to specifications. • The interference fit dowel pins used on 4.8 L (T) engines must be replaced with an oversize dowel pin when installing the flywheel. 4. W hen installing the original flywheel, ream the dowel pin holes with Tool J-22808-2. W hen installing a new flywheel, first ream the dowel pin holes w ith Tool J-22808-2 and then finish ream ing them with Tool J-22808-1. 5. Install oversize dowel pins flush with flywheel retaining bolt surface. 6. In stall rear m ain b earing cap and torque bolts to specifications. Install oil pan with new gaskets and seals. Torque oil pan retaining screws to specifications. 7. Remove grille and grille cross brace. 8. Remove windshield washer ja r and, if equipped, A /C vacuum reservoir. 9. Disconnect radiator hoses from radiator. 10. Remove radiator to radiator support attaching brackets and remove radiator. • If equipped with autom atic transm ission, remove cooler lines from rad iato r before a ttem p tin g removal. • If equipped with A /C , remove condenser to radiator support attaching bolts and swing condenser to the side, out of the way. 11 . Remove heater hoses from engine. 12. Disconnect all necessary wiring from engine: • G enerator • D istributor • All sending switches • S tarte r 13. Raise vehicle. 14. Remove fuel line hose from suction side of fuel pump. 15. Drain crankcase. 16. Remove propshaft and plug end of transmission. 17. Remove exhaust pipe from manifold flange. 18. Remove linkage from transm ission and disconnect speedometer cable. 19. Remove transm ission m ount bolts. • If equipped with m anual transm ission, disconnect clutch linkage and remove clutch cross shaft. 20. Remove engine m ount "th ro u g h " bolts. 21. Lower vehicle. 22. A ttach lifting devise to engine. 23. Raise engine slightly and remove right hand m ount assembly from engine. 24. Remove engine/transm ission assembly. Installation ("G " Van/Code D Engine) 1. Place engine/transm ission assembly into vehicle. 2. Install right hand engine m ount assembly and lower engine onto m ounts. 3. Remove lifting tool. 4. R aise vehicle and install engine m ount " th ro u g h " 1. Disconnect battery negative cable a t battery. 2. D rain cooling system. 3. Remove engine cover. 4. Remove air cleaner. 5. If equipped, evacuate A /C system and remove A /C compressor. 6. D isconnect accelerato r linkage a t c a rb u reto r and remove carburetor from manifold. bolts. Torque to specifications. transm ission m ount bolts. T orque to specifications. Connect transm ission shift linkage and speedom eter cable. • If equipped w ith m anual transm ission, connect clutch linkage and install clutch cross shaft. A ttach exhaust pipe to manifold flange. Install propshaft. Connect fuel tank line to fuel pump. Lower vehicle. Connect all wiring to engine components: • G enerator • D istributor • All sending units • S tarter 5. Install 6. ENGINE ASSEMBLY Removal ("G " Van/Code D Engine) 6A1-29 7. 8. 9. 10. 11 . LIGHT TRUCK SERVICE MANUAL 6A1-30 IN-LINE 6 12. Connect heater hoses to engine. 13. Install radiator and hold in place with radiator to support attaching brackets. • If equipped with A utom atic Transm ission, connect cooler lines to radiator. • If equipped with A /C , install condenser in front of radiator. Bolt to radiator support. 14. Connect radiator hoses to radiator. 15. Install windshield washer ja r and, if equipped, A /C vacuum reservoir. 16. Install grille cross brace and grille. 17. Using a new pad gasket, install carburetor. Connect accelerator linkage. 18. If equipped, m ount A /C compressor. 19. Fill crankcase with oil. 20. Fill cooling system. 21. Connect battery negative cable and start engine. Check ignition tim ing and adjust carburetor if necessary. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 22. Install air cleaner and engine cover. Removal (CK Series/Code D & T Engines) 1. 2. 3. 4. Disconnect b attery cables at battery. Remove air cleaner. Drain cooling system. Disconnect accelerator cable from carburetor throttle lever. • If equipped with autom atic transm ission, remove detent cable from carburetor throttle lever. 5. Disconnect all wiring from engine. 6. Remove radiator hoses from radiator. 7. Remove heater hoses from engine. 8. Remove radiator. 9. Remove fan and w ater pump pulley. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. Disconnect fuel line from fuel pump. Remove vehicle hood. Raise vehicle. Remove starter. Remove flywheel or torque converter splash shield, as applicable. Disconnect exhaust pipe from exhaust m anifold flange. W ire up and out of way. Remove engine m ount ’through’ bolts. • If equipped with autom atic transm ission, remove converter to flex plate bolts. • If ’K’ model, remove strut rods at motor mounts. Remove bell housing to engine retaining bolts. Support transm ission with chain. Lower vehicle. A ttach engine lifting device. 20. Remove engine. Installation (CK Series/Code D & T Engines) 1. Place engine in vehicle. 2. Raise vehicle. 3. Install bell housing to engine retaining bolts. Torque to specifications. IKHT TRUCK SERVICE MANUAL 16. 17. 18. 19. 20. • If equipped with au to m a tic transm ission, install torque converter to flex plate attaching bolts. Torque to specifications. Install engine mount to fram e retaining bolts. Torque to specifications. Connect exhaust pipe to exhaust manifold flange. Install flywheel or torque converter splash shield, as applicable. Install starter. Torque bolts to specifications. Lower vehicle. A ttach fuel line to fuel pump. Install w ater pump pulley and fan. Torque bolts to specifications. Install radiator. Connect heater hoses to engine. Connect radiator hoses to radiator. Connect all wiring to engine. Connect accelerator cable to carburetor throttle lever. • If equipped with autom atic transmission, connect detent cable to throttle lever. Fill cooling system. Fill crankcase with oil. Install vehicle hood. Connect battery cables, start engine. Check tim ing and carburetor adjustm ent. A djust if necessary. Install air cleaner. CRANKSHAFT Removal 1. Remove engine as previously outlined. Remove clutch, if applicable, and flywheel and m ount engine on stand. 2. Remove the oil dipstick and oil dipstick tube. 3. Remove the spark plugs. 4. Remove crankshaft pulley and torsional dam per. 5. Remove oil pan and oil pump. 6. Remove crankcase front cover. 7. Remove the connecting rod caps and push the pistons to the top of bores. 8. Remove main bearing caps and lift cranksahft out of cylinder block. 9. Remove rear main bearing oil seal and main bearings from cylinder block and m ain bearing caps. Cleaning and Inspection 1. W ash crankshaft in solvent and dry with compressed air. 2. M easure dim ensions of m ain bearing jo u rn als and crankpins with a m icrom eter for out-of-round, taper or undersize. (See Specifications.) 3. Check crankshaft for run-out by supporting the front and rear main bearing journals in "V " blocks and check at the front and rear interm ediate journals with a dial indicator. (See Specifications.) 4. R eplace or recondition th e cra n k sh aft if out of specifications. Installation IN-LINE 6 APPLY SEALANT TO SHADED AREAS ONLY Fig. 6Al-46--Sealing Bearing Cap 1. Install rear main bearing oil seal in cylinder block and rear main bearing cap grooves. Install with lip of seal tow ard front of engine. Install lip and helix towards front of engine. 2. L ubricate lips of seal with engine oil. Keep oil off parting line surface. 3. In stall m ain bearings in cylinder block and m ain bearing caps then lubricate bearing surface with engine oil. 4. Install crankshaft, being careful not to dam age bearing surfaces. 6A1-31 5. Apply a thin coat of brush-on type oil sealing com ­ pound to block m ating surface and corresponding surface of cap only (fig. 6A1-46). Do not allow sealer on crankshaft or seal. 6. Install main bearing caps with arrows pointing toward front of engine. 7. T orque all except re ar m ain bearing cap bolts to specifications. Torque rear main bearing cap bolts to 10-12 lbs. ft. (14-16 N-m) then tap end of crankshaft, first rearw ard then forward with a lead ham m er. This will line up rear main bearing and crankshaft thrust surfaces. R etorque all m ain bearing cap bolts to specifications. 8. M easure crankshaft end play with a feeler gage. Force crankshaft forward and m easure clearance between the front of the rear main bearing and the crankshaft thrust surface. 9. Install flywheel and torque to specifications. Align dowel hole in flywheel with dowel hole in crankshaft. • On vehicles equipped with autom atic transm issions, install flywheel with the converter attaching pads towards transmission. Gear Replacement Remove crankshaft gear using Tool J-8105 and install using Tool J-5590 (fig. 6A1-47). REMOVAL IN Fig. 6A l-47--G ear Replacement LIGHT TRUCK SERVICE MANUAL TRUCK M AN U AL 4.1 (D) 4.8 (T) LE3 L25 .9270-.9273 .00015-.00025 PRODUCTION CLEARANCE .001 M A X . SERVICE RPO 3.876 BORE STROKE COMPRESSION RATIO 4.120 8.25:1 8.0:1 MAIN JOURNAL DIAMETER TAPER ALL 2.2979-2.2994 DIAMETER 1-5-3-6-2-4 C YLIN D ER BORE: TAPER 3.8750-3.8780 PRODUCTION .0005 M AX. SERVICE .002 M AX. PRODUC­ TION .0008-.0016 INTERFERENCE FIT IN ROD CRANKSHAFT 3.530 FIRING ORDER OUT OF ROUND L25 THRUST SIDE OUT OF ROUND PRODUCTION .0002 M A X . SERVICE .001 M A X . PRODUCTION .0002 M A X . SERVICE .001 M A X . .0005 M AX. RELIEF SIDE MAIN BEARING CLEARANCE .0005 M AX. # 1 -6 .0010-.0024 # 7 .0016-.0035 PRODUCTION .001 M AX. SERVICE SERVICE # 1 -6 .0010-.0025 PRODUCTION .0010-.0020 .0026-.0036 .0030 M AX. .0045 M A X . DIAMETER #7 1.999-2.000 2.099-2.100 CLEARANCE SERVICE PRODUCTION .0005 SERVICE .001 M A X . PRODUCTION .0005 TAPER CRANKPIN PISTON RIN G: 0 M P R E S S 1 o TOP GROOVE PRODUC­ CLEAR­ TION 2ND ANCE SERVICE GAP PRODUC­ TION 0 1 L GROOVE CLEAR­ ANCE .0020-.0040 .0012-.0032 HI LIM IT + .001 .0 1 0.0 2 0 2ND .010-.020 PRODUCTION OUT OF ROUND .0020-.0040 TOP SERVICE N .0012-.0027 SERVICE .001 M A X . .0010-.0026 PRODUCTION SERVICE .0030 ROD SIDE CLEARANCE HI LIM IT + .010 .005 M AX. ROD BEARING CLEARANCE .005-.0055 .006-.017 CAMSHAFT LOBE LIFT ± .002 INTAKE EXHAUST .2315 .2217 .2315 SERVICE HI LIM IT + .001 PRODUCTION .015-.055 JOURNAL DIAMETER 1.8677-1.8697 SERVICE HI LIM IT + .010 CAMSHAFT END PLAY .003-.008 GAP * VIN Designation ggJI .002-.006 CRANKSHAFT END PLAY PISTON: C IN-LINE 6 SERVICE LITRE (*) | 6A1-32 LIGHT DIAMETER IN LINE L-6 TYPE DISPLACEMENT LE3 PISTON PIN GENERAL DATA: TORQUE SPECIFICATIONS VALVE SYSTEM_______________ LE 3 | L25 L IF T E R H YD RAULIC RO CKER A R M R A T IO 1.75:1 IN T A K E VALVE LASH ONE TURN D O W N FROM ZERO LASH EXHAUST FACE A N G L E ( IN T . & EXH.) 45° 46° SE AT A N G L E ( IN T. & EXH.) 46° SEAT R U N O U T SE AT W ID T H STEM CLEARANCE .002 M A X . IN T A K E 1/32-1/16 EXHAUST 1/16-3/32 P R O D U C TIO N SE RVIC E FREE LENG TH VALVE SPRING ( O U TE R ) .0010-.0027 INT. EXH. PRESSURE LBS. @ IN. .0015-.0032 HI I IM IT MIU[V111 INTAKE + .002 EXHAUST 2.08 CLOSED 7 8 -8 6 @ 1.66 OPEN 1 7 0 -1 8 0 @ 1.26 I N S T A L L E D H E IG H T 1.66 ± 1 /3 2 " FREE L E N G TH 1.94 APPROX. # OF COILS 4 D AM PER C a m sha ft T h ru s t P la te ......................................... 80 lb. in. C ra n ksh aft F ron t C o v e r ....................................... 80 lb. in. F lyw heel H o using C over ................................... 80 lb. in. Oil Pan (To Crankcase) (1/4-20) .......................80 lb. in. Oil Pan (To F ront Cover) ................................... 50 lb. in. Oil P um p C o v e r......................................................70 lb. in. Rocker A rm C over ............................................... 45 lb. in. C o n n e ctin g Rod C a p ............ .............................. 35 lb. ft.* C lutch Pressure P la t e ......................................... 20 lb. ft.* Oil Pan (To C rankcase) 5 /1 6 -1 8 ).......................75 lb. in. Oil P u m p ................................................................ 115 lb. in. Push Rod C over ....................................................50 lb. in. W a te r P u m p ............................................................15 lb. in. C lutch Pressure P la t e ....................................... 30 lb. ft.@ D is trib u to r C la m p ..................................................25 lb. ft. F lyw heel H o usin g ..................................................30 lb. ft. M a n ifo ld (E xhaust) ........................................... 30 lb. ft. 2 M a n ifo ld (E xhaust To Inlet) .............................45 lb. ft. M a n ifo ld To H e a d ................................................40 lb. f t . 2 T h e rm o s ta t H o u s in g ............................................. 30 lb. ft. W a te r O u t le t ................................... .....................30 lb. ft. C o n necting Rod C a p ......................................... 40 lb. ft.@ M a in B earing C a p ..................................................65 lb. ft. F ly w h e e l.................................................................. 60 lb. ft.* T o rsio n a l D a m p e r ............................................. 60 lb. ft.@ C y lin d e r H e a d ..........................................................95 lb. f t . 1 T e m p e ra tu re S e nd ing U n i t ................................. 20 lb. ft. Oil F ilte r .............................................................. Hand T ig h t Oil Pan D rain P lu g ................................................. 20 lb. ft. F ly w h e e l.............................................................. 110 1b. ft.@ S park P lu g ..........................................................17-27 lb. ft. * 4.1 (D) o n ly @ 4.8 (T) o n ly 1 Except LH Front Bolt 85 lb. ft. 2 Non-Integral Head SMALL BLOCK 6A4-1 SECTION 6A4 5.0L (G) V-8 - RPO LG9 5.0L (F) V-8 - RPO LF3 5.0L (H) V-8 - RPO LE9 5.7L (L) V-8 - RPO LS9 5.7L (M) V-8 - RPO LT9 Contents G eneral Description....................................................... Engine L ubrication........................................................ On Vehicle Service........................................................ Engine M o u n ts............................................................. Intake M anifold........................................................... Exhaust M anifold........................................................ Rocker Arm C over...................................................... Valve M echanism ........................................................ Valve Stem Oil Seal and /or Valve S p rin g .................................................................. . Valve L ifte rs................................................................. C ylinder H ead A ssem bly.......................................... Rocker A rm S tu d s....................................................... Valve G uide Bores....................................................... Valve S e a ts ................................................................... Valves.............................................................................. 6A4-1 6A4-2 6A 4-11 6A 4-11 6A4-11 6A4-12 6A 4-12 6A4-13 6A4-14 6A4-14 6A4-15 6A4-18 6A4-19 6A4-19 6A4-19 Torsional D am per........................................................ Crankcase Front C o v er.............................................. Oil Seal (Front C ov er)............................................... C a m s h a ft....................................................................... C am shaft B earings...................................................... Oil P a n ........................................................................... Oil Pum p........................................................................ Connecting Rod B earin g s........................... ............. M ain B earings.............................................................. Oil Seal (R ear M a in )................................................. Connecting Rod Piston A sem blies.......................... Cylinder Block.............................................................. Oil Filter Bypass V alve.............................................. Engine A ssem bly......................................................... C ra n k sh a ft..................................................................... Sprocket or G ear R eplacem ent................................ Specifications.................................................................. 6A4-19 6A4-20 6A4-20 6A4-21 6A4-21 6A4-22 6A4-23 6A4-23 6A4-24 6A4-26 6A4-28 6A4-31 6A4-32 6A4-32 6A4-33 6A4-34 6A4-35 GENERAL DESCRIPTION CYLINDER BLOCK The cylinder block is made of cast iron and has 8 cylinders arranged in a "V " shape with 4 cylinders in each bank. Five main bearings support the crankshaft which is retained by bearing caps th at are m achined with the block for proper alignment and clearnances. Cylinders are com­ pletely encircled by coolant jackets. CYLINDER HEAD The cylinder heads are cast with individual intake and exhaust ports for each cylinder. Valve guides are integral, and rocker arm s are retained on individual studs. CRANKSHAFT AND BEARINGS The crankshaft is cast nodular iron, and is supported by five main bearings. N um ber five bearing is the end thrust bearing. M ain bearings are lubricated from oil holes which intersect the cam shaft bearings. The cam shaft bearings are fed oil by the main oil gallery which is rifle drilled down the center of the block, above the cam shaft. Two additional oil gallerys are on either side of the main oil gallery to provide an oil supply for the hydraulic lifters. A torsional dam per on the forward end of the crank­ shaft dampens any engine torsional vibrations. CAMSHAFT AND DRIVE The cast iron cam shaft is supported by five bearings and is chain driven. A steel or sintered iron crankshaft gear drives the timing chain which in turn drives the cam shaft through either a nylon/alum inum or cast iron gear depend­ ing on application. Cam lobes are ground, hardened and tapered with the high side toward the rear. This, coupled with a spherical face on the lifter, causes the valve lifters to rotate. C am shaft bearings are lubricated through oil holes which intersect the main oil gallery. The main oil gallery is rifle drilled down the center of the block, above the cam shaft. PISTONS AND CONNECTING RODS The pistons are made of cast alum inum alloy using two compression rings and one oil control ring. Piston pins are L IG H T T R U C K SERVICE M ANUAL 6A4-2 SMALL BLOCK offset 1/16" (1.6m m ) tow ard the thrust side (right hand side) to provide a gradual change in thrust pressure against the cylinder wall as the piston travels its path. Pins are Chrom ium steel and have a floating fit in the pistons They are retained in the connecting rods by a press fit. Connecting rods are m ade of forged steel. Full pressure lubrication is directed to the connecting rods by drilled oil passages from the adjacent main bearing journal. Oil holes at the connecting rod journals are located so th at oil is supplied to give m axim um lubrication just prior to full bearing load. VALVE TRAIN A very simple ball pivot-type train is used. Motion is transm itted from the cam shaft through the hydraulic lifter and push rod to the rocker arm . The rocker arm pivots on its ball and transm its the cam shaft motion to the valve. The rocker-arm ball is retained by a nut. HYDRAULIC VALVE LIFTERS H ydraulic Valve Lifters are used to keep all parts of the valve train in constant contact. The hydraulic lifter assembly consists of: the lifter body, which rides in the cylinder block boss, a plunger, a push rod seat, a m etering valve, a plunger spring, a check ball and spring, a check ball retainer and a push rod seat retainer. W hen the lifter is riding on the low point of the cam, the plunger spring keeps the plunger and push rod seat in contact with the push rod. W hen the lifter body begins to ride up the cam lobe, the check ball cuts off the transfer of oil from the reservoir below the plunger. The plunger and lifter body then rise as a unit, pushing up the push rod and opening the valve. As the lifter body rides down the other side of the cam, the plunger follows with it until the valve closes. The lifter body continues to follow the cam to its low point, but the plunger spring keeps the plunger in contact with the push rod. The ball check valve will then move off its seat and the lifter reservoir will rem ain full. INTAKE MANIFOLD The intake manifold is of cast iron double level design for efficient fuel distribution. The carburetor pad is centrally located with a passage running underneath the pad (E .F.E .) through which exhaust gases are forced to promote faster fuel vaporization when the engine is cold. An EG R port is also cast into the manifold for the m ixture of exhaust gases with the fuel air mixture. EXHAUST MANIFOLDS Two cast iron exhaust manifolds are used to direct exhaust gases from the combustion cham bers to the exhaust system. The right hand side m anifold receives a heat shield th at is used to route heated air to the air cleaner for better fuel vaporization. COMBUSTION CHAMBERS C om bustion C ham bers are cast to insure uniform shape for all cylinders. Spark plugs are located between the intake and exhaust valves. The contoured wedge shape of the combustion cham ber minimizes the possibility of detonation, facilitates breath ­ ing, and provides swirling turbulence for smooth, complete combustion. ENGINE LUBRICATION Full pressure lubrication through a full flow oil filter, is furnished by a gear-type oil pump. The distributor, driven by a helical gear on the cam shaft, drives the oil pump. The main oil gallery feeds oil, through drilled passages, to the LIG H T TRUCK SERVICE M A N U A L cam shaft and crankshaft to lubricate the bearings. The valve lifter oil gallery feeds the valve lifters which, through hollow push rods, feed the individually mounted rocker arms (fig. 6A4-1 and 6A4-2). SMALL BLOCK 6A4-3 Fig. 6A4-1--Engine Lubrication L IG H T TRUCK SERVICE M ANUAL 6A4-4 SMALL BLOCK Fig. 6A4-2--Engine Lubrication L IG H T TR U C K SERVICE M AN U AL SMALL BLOCK 6A4-5 LIG H T T R U C K SERVICE M A N U A L 6A4-6 SMALL BLOCK L IG H T T R U C K SERVICE M A N U A L SMALL BLOCK 6A4-7 Fig. 6A4-5--"P" Series Engine Front Mount LIGHT T R U C K SERVICE M A N U A L 6A4-8 SMALL BLOCK Fig. 6A 4-6--"G " Series Engine Mounts LIG H T T R U C K SERVIC E M A N U A L SMALL BLOCK 6A4-9 Fig. 6A4-7--"K" Series Engine Mounts L IG H T TR U C K SERVICE M AN U AL 6A4-10 SMALL BLOCK Fig. 6A4-8--"C" Series Engine Mounts L IG H T T R U C K SERVIC E M A N U A L SMALL BLOCK 6A4-11 ON VEHICLE SERVICE ENGINE MOUNTS INTAKE MANIFOLD E ngine m ounts (fig. 6 A 4 -3 - 6 A 4 -8 ) are the nonad ju sta b le type and seldom req u ire service. Broken or d e te rio ra ted m ounts should be replaced im m ediately, because of the added strain placed on other m ounts and drive line components. Removal 1. D rain radiator and remove air cleaner. 2. Disconnect: • B attery negative cable at battery. • R adiator upper hose and heater hose at manifold. Checking Engine Mounts Front Mount Raise the engine to remove weight from the mounts and to place a slight tension in the rubber. Observe both mounts while raising engine. If an engine m ount exhibits: a. H ard rubber surface covered with heat check cracks; b. R ubber separated from a metal plate of the mount; c. R ubber split through center replace the m ount. If th e re is relative m ovem ent between a m etal plate of the m ount and its attaching points, lower the engine on the m ounts and tighten the screws or nuts attaching the mount to the engine, fram e, or bracket. • A ccelerator linkage a t carburetor. 3. 4. 5. 6. • Fuel line at carburetor. • Crankcase ventilation lines. • Spark advance hose at distributor. Remove distributor cap and m ark rotor position with chalk, then remove distributor. Remove air conditioning compressor and bracket (if equipped), accelerator return spring and bracket, and accelerator bellcrank. Remove generator upper mounting bracket. Remove manifold attaching bolts, then remove m ani­ fold and carburetor as an assembly. Discard gaskets. Remove A .I.R . crossover. Rear Mount 7. R aise the vehicle on a hoist. Push up and pull down on the transm ission tailshaft while observing the transm ission m ount. If the rubber separates from the m etal plate of the m ount or if the tailshaft moves up but not down (m ount bottom ed out) replace th e m ount. If th ere is relative movement between a m etal plate of the m ount and its attaching point, tighten the screws or nuts attaching the m ount to the transm ission or crossm em ber. 8. If manifold is being replaced, transfer: • C arburetor and carburetor attaching bolts. • T em perature sending unit. Front Mount Replacement 1. Rem ove m ount retain in g bolt from below fram e m ounting bracket. 2. R aise front of engine and rem ove m ount-to-engine bolts and remove mount. NOTICE: Raise engine only enough for sufficient clear­ ance. Check for interference between rear of engine and cowl panel which could cause distributor dam age. 3. Replace mount to engine and lower engine into place. 4. Install retain in g bolt and torque all bolts to specifications. Rear Mount Replacement 1. Support engine weight to relieve rear mounts. 2. Remove crossm em ber-to-m ount bolts. 3. On " P " Series with m anual transm ission and propeller shaft parking brake, remove m ount attaching bolts from fram e outrigger and clutch housing and remove rear m ounting cushions. 4. Rem ove m ount-to-transm ission bolts, then rem ove mount. 5. On " P " Series with m anual transm ission and propeller shaft parking brake, install new m ounting cushions and bolts. 6. Install new mount on transm ission. 7. W hile lowering transm ission, align and start cross­ m em ber-to-m ount bolts. 8. Torque bolts to specifications then bend lock tabs to bolt head as applicable. • T herm ostat with housing (use new gasket). • H eater hose adapter. • E G R Valve (use new gasket). • TVS switch. • Vacuum fitting(s). • Choke spring assembly (where applicable). Installation 1. Clean gasket and seal surfaces on manifold, block, and cylinder heads with degreaser. Remove all RTV th at is loose or will cause installation interference. 2. Install gaskets on cylinder heads and place a 3 /1 6 " (5m m ) bead of RTV , # 1 0 5 2 3 6 6 or equivalent, on the front and rear ridges of the cylinder case. Extend the bead 1/2" (13m m ) up each cylinder head to seal and retain the manifold side gaskets. 3. Install manifold and torque bolts to specifications in the sequence outlined in fig. 6A4-9. 4. Install (if rem oved) air com pressor and brack et, accelerator bellcrank. 5. Install distributor, positioning rotor at chalk m ark, then install distributor cap. 6. Connect: • Spark advance hose a t distributor. • Crankcase ventilation lines. • Fuel line at carburetor. • A ccelerator linkage at carburetor. • B attery negative cable at battery. 7. Install air cleaner. 8. Fill w ith coolant (refer to section 6B for proper procedure), start engine, adjust ignition timing and carburetor idle speed (if necessary) and check for leaks. LIG H T T R U C K SERVICE M A N U A L 6A4-12 SMALL BLOCK W IN G NUT LOWER STOVE NOTE: Inboard flange of lower stove must be installed on top of rib of exhaust manifold. CARBURETOR TEE AIR CLEANER HOSE 3 5 0 /4 0 0 V8 4Bbl IvSwfBl UPPER STOVE LOWER STOVE Fig. 6A4-10--Carburetor Heat Stove Assembly EXHAUST MANIFOLD Removal 1. Remove carburetor heat stove pipe. 2. Remove the spark plug wiring heatshields. 3. D isconnect exhaust pipe from m anifold and hang exhaust pipe from fram e with wire. 4. Remove end bolts then remove center bolts and remove manifold. Installation 1. 2. 3. 4. 5. 6. • If installing a new right side manifold, the carburetor heat stove m ust be transferred from the old unit (fig. 6A4-10). Clean m ating surfaces on m anifold and head, then install m anifold in position and install bolts (fingertight). Torque manifold bolts to specifications. Connect exhaust pipe to manifold. Install carburetor heat stove pipe. Install spark plug wiring heatshields. S tart engine and check for leaks. ROCKER ARM COVER Removal 1. Disconnect battery negative cable. 2. Remove air cleaner. 3. Disconnect crankcase ventilation hoses at rocker arm covers. 4. Disconnect electrical wiring harness from rocker arm clips. 5. Remove carburetor heat stove pipe from right exhaust manifold. 6. If the vehicle is equipped with air conditioning, remove the A /C compressor rear brace (fig. 6 A 4 -11). L IG H T T R U C K SERVIC E M A N U A L SMALL BLOCK 6A4-13 push rods in a rack so they may be reinstalled in the same locations. Installation and Adjustment 7. Remove rocker arm cover to head attaching bolts and remove rocker arm cover. NOTICE: If cover adheres to cylinder head, shear off by bum ping end of rocker arm cover with a block of wood and a rubber m allet. If cover still will not come loose, CAREFULLY pry until loose. DO N O T D IS T O R T S E A L IN G FL A N G E . Installation 1. C lean sealing surface on cylinder head and rocker arm cover with degreaser. Using a 3 /1 6 " (5m m ) bead of R TV , # 1052366 or equivalent, place rocker arm cover on the head, install retaining bolts and torque to 40 lb. in. (4.6 N-m). Loose RTV sealant, or pieces causing installation interference, m ust be removed from both cylinder head and cover seal surfaces prior to applying new sealant. • W hen going around the attaching bolt holes, always flow the RTV on the inboard side of the holes. Install cover and torque bolts while RTV is still wet (within 10 minutes). 2. On A /C equipped vehicles, install the A /C compressor upper brace. A djust pulley belt to specification. • W henever new rocker arm s an d /o r rocker arm balls are being installed, coat bearing surfaces of rocker arm s and rocker arm balls with "M olykote" or its equivalent. 1. Install push rods. Be sure push rods seat in lifter socket. 2. Install rocker arm s, rocker arm balls and rocker arm nuts. T ighten rocker arm nuts until all lash is elim inated. 3. A djust valves when lifter is on base circle of cam shaft lobe as follows: a. C rank engine until m ark on torsional dam per lines up with center or "O " m ark, on the tim ing tab, fastened to the crankcase front cover, and the engine is in the # 1 firing position. This may be determ ined by placing fingers on the # 1 valve as the m ark on the dam per comes near the " O " m ark on the crankcase front cover. If the valves are not moving, the engine is in the # 1 firing position. If the valves move as the, m ark comes up to the tim ing tab, the engine is in # 6 firing position and should be rotated one more tim e to reach the # 1 position. b. W ith the engine in the # 1 firing position as just determ ined, the following valves may be adjusted: - E xhaust--1, 3,4 , 8 -- I n ta k e - 1, 2, 5, 7 c. Back out adjusting nut until lash is felt at the push rod then tu rn in adjusting n ut until all lash is removed. This can be determ ined by rotating push rod while turning adjusting nut (fig. 6A 4-12). W hen play has been removed, turn adjusting nut in one full additional turn (to center lifter plunger). d. R otate the engine one revolution until the pointer "O " m ark and torsional dam per m ark are again in alignm ent. This is the # 6 firing position. W ith the engine in this position the following valves may be adjusted. 3. Install carburetor heat stove pipe. 4. C onnect electrical wiring harness at clips on rocker arm cover. 5. Connect crankcase ventilation hoses. 6. Install air cleaner. Connect b attery negative cable, sta rt engine and check for leaks. VALVE MECHANISM Removal 1. Remove rocker arm covers as previously outlined. 2. Remove rocker arm nuts, rocker arm balls, rocker arm s and push rods. Place rocker arm s, rocker arm balls and LIG H T T R U C K SERVICE M AN U AL 6A4-14 SMALL BLOCK 2. Remove spark plug, rocker arm and push rod on the cylinder(s) to be serviced. 3. Install air line adapter Tool J-23590 to spark plug port and apply compressed air to hold the valves in place. 4. Using Tool J-5892 to compress the valve spring, remove the valve locks, valve cap, oil shedder and valve spring and dam per (fig. 6A4-13). 5. Remove the valve stem oil or head oil seal. Installation 1. Install valve stem seal over valve stem and seat against head. 2. Set the valve spring and dam per, oil shedder and valve cap in place. Compress the spring with Tool J-5892 and install oil seal in the lower groove of the stem , making sure the seal is flat and not twisted. A light coat of oil on the seal will help prevent twisting. 3. Install the valve locks and release the compressor tool m aking sure the locks seat properly in the upper groove of the valve stem. G rease may be used to hold the locks in place while releasing the compressor tool. 4. Using tool J-23994, apply vacuum to the valve cap to m ake sure no air leaks past the seal. Fig. 6A4-12--Valve Adjustment 5. Install spark plug, and torque to 22 lb. ft. (30 N-m). -- Exhaust--2, 5 ,6 , 7 - I n ta k e - 3 ,4 ,6 , 8 4. Install rocker arm covers as previously outlined. 5. S ta rt engine and a d ju st c a rb u re to r idle speed, if needed. VALVE STEM OIL SEAL and/or VALVE SPRING (Fig. 6A 4-11A) Removal 6. Install and ad ju st valve m echanism as previously outlined. VALVE LIFTERS H ydraulic valve lifters very seldom require attention. The lifters are extrem ely simple in design, readjustm ents are not necessary, and servicing of the lifters requires only th at care and cleanliness be exercised in the handling of parts. Removal 1. Remove rocker arm cover as previously outlined. 1. Remove intake manifold as previously outlined. 2. Remove valve mechanism as previously outlined. 3. Remove valve lifters. Place valve lifters in a rack so that they may be reinstalled in the sam e location. Installation 1. C oat foot of valve lifters w ith "M o ly k o te" or its equivalent and install valve lifters. M ake sure lifter foot is convex. 2. Install intake manifold as previously outlined. 3. Install and adjust valve m echanism as outlined. Disassembly 1. Hold the plunger down with a push rod, and using the blade of a small screw driver, remove the push rod seat retainer. 2. Remove the push rod seat and m etering valve (fig. 6A414). J-2 3 5 9 0 ADAPTER Fig. 6A4-13--Compressing Valve Spring L IG H T T R U C K SERVIC E M A N U A L 3. Remove the plunger, ball check valve assembly and the plunger spring. 4. Remove the ball check valve and spring by prying the ball retainer loose from the plunger with the blade of a small screw driver (fig. 6A 4-15). SMALL BLOCK 6A4-15 Assembly 1. Lifte r Body 2. Push Rod Seat 3. M etering Valve 4 Check Ball 5 Check Ball Retainer 6 7 8 9 Push Rod Seat Retainer Plunger Check Ball Spring Plunger Spring Fig. 6A4-14--Hydraulic Valve Lifter 1. Place the check ball on mall hole in bottom of the plunger. 2. Insert check ball spring >n seat in ball retainer and place retainer over ball scthat spring rests on the ball. Carefully press the retaner into position in plunger with the blade of a small crew driver (fig. 6 A 4 -16). 3. Place the plunger springover the ball retainer and slide the lifter body over tie spring and plunger, being careful to line up the oil eed holes in the lifter body and plunger. 4. Fill the assembly with SAE 10 oil, then insert the end of a 1/8" drift pin into tie plunger and press down solid. Do not attem pt to for;e or pump the plunger. A t this point, oil holes in the ifter body and plunger assembly will be aligned (fig. 6A4-17) 5. Insert a 1/16" drif: pin through both oil holes to hold the plunger down against :he lifter spring tension (fig. 6A4-17). 6- Remove the l/8 " d r if t p ir, refill assem bly w ith SA E 10 oil. 7. Install the metering valve and push rod seat (fig. 6A414). 8. Install the push rod sea: retainer, press down on the push rod seat and remove the 1/16" drift pin from the oil holes. The lifter is now completely assembled, filled with oil and ready for installation. Before installing lifters, coat the bottom of the lifter with " Molykote " or its equivalent. CYLINDER HEAD ASSEMBLY Removal 1. Remove intake manifold as previously outlined 2. Remove generator lower m ounting bolt and lay unit aside. 3. Remove exhaust manifolds as previously outlined. Fig. 6A4-15--Removing Ball Check Valve Cleaning and Inspection Thoroughly clean all parts in cleaning solvent, and inspect them carefully. If any parts are dam aged or worn, the entire lifter assembly should be replaced. If the lifter body wall is scuffed or worn, inspect the cylinder block lifter bore. If the bottom of the lifter is scuffed or worn, inspect the cam shaft lobe. If the push rod seat is scuffed or worn, inspect the push rod. An additive containing EP lube, such as EOS, should always be added to crankcase oil for run-in when any new cam shaft or lifters are installed. All dam aged or worn lifters should be replaced. W henever a new cam shaft is installed, replace oil, oil filter and all valve lifters. Install G M E.O.S. or equivalent over the cam and lifter feet after the parts are installed. • For proper lifter rotation during engine operation, lifter foot m ust be convex. Fig. 6A4-16--lnstalling Ball Chtk Valve LIG H T T R U C K SERVICE M A N U A L 6A4-16 SMALL BLOCK 3. Remove valves from cylinder head and place them in a rack in their proper sequence so th a t they can be assembled in their original positions. Cleaning 1. Clean all carbon from com bustion cham bers and valve ports using Tool J-8089 (fig. 6 A 4 -19). 2. Thoroughly clean the valve guides using Tool J - 8 101. 3. Clean all carbon and sludge from push rods, rocker arm s and push rod guides. 4. Clean valve stems and heads on a buffing wheel. 5. C lean carbon deposits from head gasket m ating surface. Inspection 1. Inspect the cylinder head for cracks in the exhaust ports, combustion cham bers, or external cracks to the coolant cham ber. 2. Inspect the valves for burned heads, cracked faces or dam aged stems. Fig. 6A4-17--Assenbling Hydraulic Lifter 4. Drain cylinder block of coolant. 5. If vehicle is equipped wi.h A /C , remove A /C com pres­ sor and forw ard mounting bracket. Lay unit aside. NOTICE: Excessive valve stem to bore clearance will cause excessive oil consumption and may cause valve breakage. Insufficient clearance will result in noisy and sticky functioning of the valve and d isturb engine smoothness. 6. Remove valve push rods as previously outlined. 7. Remove cylinder head belts, cylinder head and gasket. Place cylinder head on two blocks of wood to prevent damage. Disassembly 1. With cylinder head removed, remove valve rocker arm nul.s, balls and rocker arm s (if not previously done). 2. U sng Tool J-8062, compress the valve springs (fig. 6 A M 8) and remove valve keys. Release the compres­ sor ool and remove rotators or spring caps, oil shedders springs and spring dam per, then remove oil seals and ialve spring shims. Fig. 6A-18--Compressing Valve Spring LIG H T T R U C K SERVIC E M A N U A L 3. M easure valve stem clearance (fig. 6A4-20) as follows: a. Clam p a dial indicator on one side of the cylinder head rocker arm cover gasket rail. b. Locate the indicator so th at movement of the valve stem from side to side (crosswise to the head) will cause a direct movement of the indicator stem. The indicator stem m ust contact the side of the valve stem ju st above the valve guide. c. Drop the valve head about 1/16" (1.6m m ) off the valve seat. d. Move the stem of the valve from side to side using light pressure to obtain a clearance reading. If clearance exceeds specifications, it will be necessary to ream valve guides for oversize valves as outlined. 4. Check valve spring tension with Tool J-8056 spring tester (fig. 6A 4-21). Springs should be compressed to Fig. 6A4-19--Cleaning Combustion Chambers SMALL BLOCK 6A4-17 SEAL SHIELD DAMPER * * ROTATOR O N EXHAUST VALVE * NOT USED ON 250 CU. IN. L6 Fig. 6A4-22--Valve Spring Installation Fig. 6A4-20--Measuring Valve Stem Clearances Fig. 6A4-23--Checking Valve Stem Oil Seals b. Compress the spring with Tool J-8062. c. Install oil seal in the lower groove of the stem , making sure th at the seal is flat and not twisted. d. Install the valve locks and release the compressor tool, making sure th at the locks seat properly in the upper groove of the valve stem. G rease may be used to hold the locks in place while releasing the com­ pressor tool. Fig. 6A4-21 --Checking Valve Spring Tension the specified height and checked against the specifica­ tions chart. Springs should be replaced if not within 10 lbs. (44 N ) of the specified load (w ithout dam pers). 5. Inspect rocker arm studs for wear or dam age. Assembly 1. Insert a valve in the proper port. 2. Assemble the valve spring and related parts as follows: a. Set the valve spring shim, valve spring, oil shedder and valve cap or rotator in place (fig. 6A4-22). 3. Install the rem aining valves. 4. Check each valve stem oil seal by placing Valve Seal Leak D etector (Tool J-23994) over the end of the valve stem and against the cap. O perate the vacuum pum p and make sure no air leaks past the seal (fig. 6A 4-23). 5. Check the installed height of the valve springs, using a narrow thin scale. A cutaw ay scale will help (fig. 6A424). M easure from the top of the shim or the spring seat to the top of the oil shedder (fig. 6A 4-25). If this is found to exceed the specified height, install a valve spring seat shim approxim ately 1/16" (1.6mm) thick. LIG H T T R U C K SERVICE M A N U A L 6A4-18 SMALL BLOCK ROCKER ARM STUDS , GRIND OUT THIS PORTION n-rp-rn l|i l|l|IM|l|> 1| 1| 1| 1J1| 1| 1| 1J1| 1| 1| 1| I| >| 1| 1| 1| 1| 1| 1| 1| 1| 1| 1 M'| Mfj'irpt' 3 4 / f 6 Fig. 6A4-24--Cutaway Scale Replacement Rocker arm studs th at have dam aged threads or are loose in cylinder heads should be replaced with new studs available in .003" and .013" oversize. S tuds m ay be installed after ream ing the holes as follows: 1. Remove old stud by placing Tool J-5802-1 over the stud, installing nut and flat washer and removing stud by turning nut (fig. 6A4-26). 2. Ream hole for oversize stud using Tool J-5715 for .003" oversize or Tool J-6036 for .013" oversize (fig. 6A4-27). NOTICE: Do not attem pt to install an oversize stud without ream ing stud hole as this could dam age the head casting. Fig. 6A4-25~Measuring Valve Spring Installed Height A t no tim e should the spring be shimmed to give an installed height under the m inim um specified. Installation • The gasket surfaces on both the head and the block m ust be clean of any foreign m atter and free of nicks or heavy scratches. Cylinder bolt threads in the block and threads on the cylinder head bolts m ust be clean as d irt will affect bolt torque. 1. If using a ST E E L gasket, coat both sides of a new gasket with a good sealer. Spread the sealer thin and even. O ne m ethod of applying the sealer th a t will assure the proper coat is with the use of a paint roller. Too m uch sealer may hold the gasket away from the head or block. Fi9- 6A4-26--Removing Rocker Arm Stud • Use no sealer if using a composition ST E E L A S­ BESTO S gasket. 2. Place the gasket in position over the dowel pins with the bead up. 3. Carefully guide the cylinder head into place over the dowel pins and gasket. OVERSIZE 4. C oat th read s of cylinder head bolts w ith sealing compound, # 1 0 5 2 0 8 0 or equivalent, and install bolts finger tight. 5. Tighten each cylinder head bolt a little at a tim e in the sequence shown in the torque sequence chart until the specified torque is reached. 6. Install exhaust manifolds as previously outlined. 7. Install intake manifold as previously outlined. 8. Install and ad ju st valve m echanism as previously outlined. LIG H T T R U C K SERVIC E M A N U A L Fig. 6A4-27--Reaming Rocker Arm Stud Bore SMALL BLOCK 6A4-19 TORSIONAL DAMPER Removal J- 6880 1. Remove fan belt, fan and pulley. 2. Remove the fan shroud assembly. • If additional operations (such as cam shaft removal) are not being perform ed, radiator removal will not be necessary. 3. Remove accessory drive pulley then remove dam per retaining bolt. 4. Install Tool J-23523 on dam per then, turning puller screw, remove dam per (fig. 6A4-30). Installation Fig. 6A4-28--lnstalling Rocker Arm Stud 3. C oat press-fit area of stud with hypoid axle lubricant. Install new stud, using Tool J-6880 as a guide. Gage should bottom on head (fig. 6A4-28). VALVE GUIDE BORES Valves with oversize stems are available (see specifica­ tions). To ream the valve guide bores for oversize valves use Tool Set J-5830. VALVE SEATS NOTICE: The inertial weight section of the torsional dam per is assembled to the hub with a rubber type m aterial. The installation procedures (with proper tool) m ust be followed or movement of the inertia weight section on the hub will destroy the tuning of the torsional dam per. 1. Coat front cover seal contact area (on dam per) with engine oil. 2. Place dam per in position over key on crankshaft. 3. Pull dam per onto crankshaft as follows: a. Install appropriate threaded end of Tool J-23523 into crankshaft. Install tool in crankshaft so th at at least 1 /2 " (13m m ) of th re ad engagem ent is obtained. R econditioning the valve seats is very im p o rtan t, because the seating of the valves m ust be perfect for the engine to deliver the power and perform ance built into it. A nother im portant factor is the cooling of the valve heads. Good contact between each valve and its seat in the head is im perative to insure th a t the heat in the valve head will be properly carried away. Several different types of equipm ent are available for reseating valves seats. The recom m endations of the m anu­ facturer of the equipm ent being used should be carefully followed to attain proper results. 4. 5. 6. Regardless of what type of equipm ent is used, however, it is essential th a t valve guide bores be free from carbon or dirt to ensure proper centering of pilot in the guide. 7. 8. b. Install plate, th rust bearing and nut to complete tool installation. c. Pull dam per into position as shown in Figure 6A431. d. Remove tool from crankshaft then install dam per retaining bolt and torque to specifications. Install accessory drive pulley. Install fan shroud. Install fan and pulley to w ater pum p hub and tighten securely. Install fan belt and adjust (see section 6B). Fill cooling system (see section 6B) and check for leaks. VALVES Valves th at are pitted can be refaced to the proper angle, insuring correct relation between the head and stem on a valve refacing mechanism. Valve stems which show excessive wear, or valves th at are warped excessively should be replaced. W hen a valve head which is warped excessively is refaced, a knife edge will be ground on part or all of the valve head due to the am ount of metal th at must be removed to completely reface. Knife edges lead to breakage, burning or pre-ignition due to heat localizing on this knife edge. If the edge of the valve head is less than 1/32" (.80m m ) thick after grinding, replace the valve. Several different types of equipm ent are available for refacing valves. The recom m endation of the m anufacturer of the equipm ent being used should be carefully followed to attain proper results. Fig. 6A4-30--Removing Torsional Damper - Typical LIG H T T R U C K SERVICE M A N U A L 6A4-20 SMALL BLOCK 2. Install new seal so that open end of the seal is toward the inside of cover and drive it into position with Tool J-23042. Support rear of cover at seal area. With Cover Installed 1. W ith torsional dam per removed, pry seal out of cover from the front with a large screw driver. Be careful not to dam age the surface on the crankshaft. 2. Install new seal so that open end of seal is toward the inside of cover and drive it into position with Tool J-23042 (fig. 6A4-32). Fig. 6A4-31--Installing Torsional Damper CRANKCASE FRONT COVER Removal 1. Remove torsional dam per as previously outlined. 2. Remove w ater pump (see section 6B). 3. Remove crankcase front cover attaching screws and remove front cover and gasket, then discard gasket. Installation 1. Clean gasket surface on block and crankcase front cover. 2. Use a sharp knife or other suitable cutting tool to remove any excess oil pan gasket m aterial th at may be protruding at the oil to engine block junction. 3. Apply a 1/8" (3m m ) bead of RTV, # 1 0 5 2 3 6 6 or equivalent, to th e jo in t form ed at the oil pan and cylinder block. 4. Coat the cover gasket with gasket sealant and place in position on cover. 5. Install cover-to-oil pan seal, lightly coat bottom of seal with engine oil, and position cover over crankshaft end. 6. Loosely install the cover-to-block upper atta c h in g screws. 7. Tighten screws alternately and evenly while pressing downward on cover so th a t dowels in block are aligned with corresponding holes in cover. Position cover so that dowels enter holes in cover without binding. Do not force cover over dowels so th a t cover flange or holes are distorted. 8. Install rem aining cover screws and torque to specifications. 9. Install torsional dam per and w ater pum p as previously outlined. Fig. 6A4-32--lnstalling Oil Seal OIL SEAL (FRONT COVER) Replacement With Cover Removed 1. W ith cover removed, pry oil seal out of cover from the front w ith a large screw driver. LIG H T T R U C K SERVICE M A N U A L Fig. 6A4-33--Measuring Camshaft Lobe Lift SMALL BLOCK 6A4-21 Inspection CAMSHAFT Measuring Lobe Lift 1. Remove the valve m echanism as previously outlined. 2. Position in d icato r w ith ball socket ad ap te r (Tool J-8520) on push rod (fig. 6A 4-33). M ake sure push rod is in the lifter socket. 3. R otate the crankshaft slowly in the direction of rotation until the lifter is on the heel of the cam lobe. A t this point, the push rod will be in its lowest position. 4. Set dial indicator on zero, then rotate the crankshaft slowly, or a tta c h an au x iliary s ta rte r sw itch and "b u m p " the engine over, until the push rod is fully raised position. • W henever the engine is cranked remotely at the starter, with a special jum per cable or other means, the distributor prim ary lead should be disconnected from the distributor (coil). 5. C om pare the total lift recorded from the dial indicator with specifications. 6. If cam shaft readings for all lobes are within specifica­ tions, remove dial indicator assembly. 7. Install and adjust valve m echanism as outlined. Removal 1. Remove valve lifters as previously outlined. 2. Remove crankcase front cover as previously outlined. The cam shaft bearing journals should be m easured with a m icrom eter for an out-of-round condition. If the journals exceed .001" (,025m m ) out-of-round, the cam shaft should be replaced. Installation W henever a new cam shaft is installed coat cam shaft lobes with "M olykote" or its equivalent. W henever a new cam shaft is installed, replacem ent of all valve lifters oil filter, and new oil is recom m ended to insure durability of the cam shaft lobes and lifter feet. 1. L ubricate cam shaft journals with engine oil and install cam shaft. 2. Install tim ing chain on cam shaft sprocket (fig. 6A435). Hold the sprocket vertically w ith the chain hanging down and align m arks on c am sh aft and crankshaft sprockets. 3. Align dowel in cam shaft with dowel hole in cam shaft sprocket then install sprocket on cam shaft. 4. Draw the cam shaft sprocket onto cam shaft using the m ounting bolts. Torque to specifications. 5. Lubricate tim ing chain with engine oil. 6. Install fuel pump push rod and fuel pump (see section 6C). 7. Install grille. 8. Install crankcase front cover as previously outlined. 9. Install valve lifters as previously outlined. 3. Remove grille. 4. Remove fuel pump and push rod (see section 6C). 5. Com plete cam shaft removal as follows: • Sprocket is a light fit on cam shaft. If sprocket does not come off easily a light blow on the lower edge of the sprocket (with a plastic m allet) should dislodge the sprocket. 6. Install two 5 /1 6 " - 18 x 4" bolts in cam shaft bolt holes then remove cam shaft (fig. 6A4-34). CAMSHAFT BEARINGS Removal C am shaft bearings can be replaced with engine com ­ pletely or p artially disassem bled. To replace bearings without complete disassembly, remove the cam shaft and crankshaft leaving cylinder heads attached and pistons in place. Before removing crankshaft, tape threads of connect­ ing rod bolts to prevent dam age to cran k sh aft. Fasten NOTICE: All cam shaft journals are the same diam eter and care m ust be used in removing cam shaft to avoid dam age to bearings. Fig. 6A4-34--Removing Camshaft Fig. 6A4-35--Camshaft Sprocket Alignment Marks LIG H T T R U C K SERVICE M A N U A L 6A4-22 SMALL BLOCK connecting rods against sides of engine so they will not be in the way while replacing cam shaft bearings. 1. W ith cam shaft and crankshaft removed, drive cam ­ shaft rear plug from cylinder block. 2. Using Tool J-6098, with nut and thrust washer in­ stalled to end of threads, index pilot in cam shaft front bearing and install puller screw through pilot. 3. Install remover and installer tool with shoulder toward bearing, m aking sure a sufficient am ount of threads are engaged. 4. Using two wrenches, hold puller screw while turning nut. W hen bearing has been pulled from bore, remove remover and installer tool and bearing from puller screw (fig. 6A4-36). 5. Remove rem aining bearings (except front and rear) in the sam e m anner. It will be necessary to index pilot in cam shaft rear bearing to remove the rear interm ediate bearing. 6. Assemble remover and installer tool on driver handle and rem ove c am sh aft front and re a r bearings by driving towards center of cylinder block (fig. 6A4-37). Installation The cam sh aft front and re a r bearings should be installed first. These bearings will act as guides for the pilot and center the rem aining bearings being pulled into place. 1. Assemble remover and installer tool on driver handle and install cam shaft front and rear bearings by driving towards center of cylinder block (fig. 6A4-37). 2. Using Tool Set J-6098, with nut then thrust washer installed to end of threads, index pilot in cam shaft front bearing and install puller screw through pilot. 3. Index cam shaft bearing in bore (with oil hole aligned as outlined below), then install remover and installer tool on puller screw with shoulder toward bearing. • N um ber one cam bearing oil hole m ust be positioned so th a t oil holes are e q u id istan t from 6 o’clock position. Fig. 6A4-37--Replacing Camshaft Front Bearing • N um ber two through num ber four bearing oil holes m ust be positioned at 5 o’clock position (tow ard left side of engine, and at a position even with bottom of cylinder bore). • N um ber five bearing oil hole m ust be in 12 o’clock position. 4. Using two wrenches, hold puller screw while turning nut. A fter bearing has been pulled into bore, remove the remover and installer tool from puller screw, and check alignm ent of oil hole in cam shaft bearing. 5. Install rem aining bearings in the sam e m anner. It will be necessary to index pilot in the cam shaft rear bearing to install the rear interm ediate bearing. 6. C oat new cam shaft rear plug O.D. with # 1 0 5 2 0 8 0 sealan t, or equivalent, and install flush to 1 /3 2 " (.80m m ) deep. OIL PAN Removal 1. D rain engine oil. 2. Remove exhaust crossover pipe. 3. On vehicles equipped w ith a u to m a tic transm ission, remove converter housing under pan. 4. On ’K’ models with autom atic transm ission, remove strut rods at motor mounts. 5. Remove oil pan and discard gaskets and seals. Installation Fig. 6A4-36--Removing Camshaft Bearings LIG H T T R U C K SERVIC E M A N U A L 1. Thoroughly clean all gasket and seal surfaces on oil pan, cylinder block, crankcase front cover and rear main bearing cap. 2. Install new oil pan side gaskets on cylinder block using gasket sealant as a retainer. Install new oil pan rear seal in rear main bearing cap groove, with ends butting side gaskets. Install new oil pan front seal in groove in crankcase front cover with ends butting side gaskets. 3. Install oil pan and torque bolts to specifications. 4. If ’K ’ model, replace strut rods. 5. Install converter housing under pan. SMALL BLOCK 6. Install exhaust crossover pipe. 7. Fill with oil, start engine and check for leaks. 6A4-23 4. Check the drive gear shaft for looseness in the pump body. 5. Inspect inside of pum p cover for w ear th a t would perm it oil to leak past the ends of the gears. OIL PUMP Removal 1. Remove oil pan as previously outlined. 2. Rem ove pum p to re a r m ain bearing cap bolt and remove pum p and extension shaft. Disassembly (Figure 6A4-38) 1. Rem ove th e pum p cover a tta c h in g screws and the pump cover. 2. M ark gear teeth so they may be reassem bled with the same teeth indexing. Remove the idler gear and the drive gear and shaft from the pump body. 3. R em ove the pressure reg u lato r valve retaining pin, pressure regulator valve and related parts. 4. If the pickup screen and pipe assembly need replacing, m ount the pump in a soft-jawed vise and extract pipe from pump. Do not disturb the pickup screen on the pipe. This is serviced as an assembly. 6. Inspect the pickup screen and pipe assem bly for dam age to screen, pipe or relief grom m et. 7. Check the pressure regulator valve for fit. Assembly (Figure 6A4-38) 1. If the pickup screen and pipe assembly was removed, it should be replaced with a new part. Loss of press fit condition could result in an air leak and loss of oil pressure. M ount the pump in a soft-jawed vise, apply sealer to end of pipe, and using Tool J-8369 (fig. 6 A 4 39) tap the pipe in place with a plastic ham m er. 2. 3. 4. 5. Cleaning and Inspection 1. W ash all p arts in cleaning solvent and dry with compressed air. 2. Inspect the pump body and cover for cracks or exces­ sive wear. 3. Inspect pum p gears for dam age or excessive wear. • The pum p gears and body are not serviced sepa­ rately. If the pum p gears or body are dam aged or worn, replacem ent of the entire oil pump assembly is necessary. 6. NOTICE: Be careful of twisting, shearing or collapsing pipe while installing in pump. Install the pressure regulator valve and related parts, Install the drive gear and shaft in the pump body. Install the idler gear in the pump body with the smooth side of gear towards pum p cover opening. Install the pump cover and torque attaching screws to specifications. Turn drive shaft by hand to check for smooth operation. Installation 1. A ssem ble pum p and extension shaft to re a r m ain bearing cap, aligning slot on top end of extension shaft with drive tang on lower end of distributor drive shaft. 2. Install pum p to rear bearing cap bolt and torque to specifications. 3. Install oil pan previously outlined. CONNECTING ROD BEARINGS Connecting rod bearings are of the precision insert type and do not utilize shims for adjustm ent. DO N O T F IL E R O D S O R RO D CA PS. If clearances are found to be excessive a new bearing will be required. Service bearings are available in standard size and .001" and .002" under.size for use with new and used standard size crankshafts, 1. 2. 3. 4. 5. 6. S haft Extension Pump Body Drive Gear and Shaft Idler Gear Pump Cover Pressure Regulator Valve 7. 8. 9. 10. Pressure R egulator Spring R etaining Pin Screws Pickup Screen and Pipe Fig. 6A4-38--Oil Pump Fig. 6A4-39--lnstalling Screen LIG H T TR U C K SERVICE M A N U A L 6A4-24 SMALL BLOCK and in .010" and .020" undersize for use with reconditioned crankshafts. On removing a connecting rod cap, it is possible to find a .009" undersize bearing. These are used in m anufacturing for selective fitting. Inspection and Replacement 1. W ith oil pan and oil pum p rem oved, rem ove the connecting rod cap and bearing. Before removal of connecting rod cap, m ark the side of the rod and cap with the cylinder num ber to assure m atched reassembly of rod and cap. 2. Inspect the bearing for evidence of wear or dam age. (Bearings showing the above should not be installed.) 3. W ipe both upper and lower bearing shells and crankpin clean of oil. 4. M easure the crankpin for out-of-round or taper with a m icrom eter. If not w ithin specifications replace or recondition the crankshaft. If within specifications and a new bearing is to be installed, m easure the maxim um diam eter of the crankpin to determ ine new bearing size required. 5. If within specifications m easure new or used bearing clearances with Plastigage or its equivalent. If a bearing is being fitted to an out-of-round crankpin, be sure to fit to the m axim um diam eter of the crankpin. If the bearing is fitted to the m inim um diam eter and the cran k p in is o u t-of-round .001" interference between the bearing and crankpin will result in rapid bearing failure. a. Place a piece of gaging plastic, the length of the bearing (parallel to the crankshaft), on the crankpin or bearing surface (fig. 6A 4-40). Plastic gage should be positioned in the middle of upper or lower bearing shell. (B earings are eccen tric and false readings could occur if placed elsewhere). Fig. 6A4-40--Gaging Plastic On Crankpin LIG H T T R U C K SERVICE M A N U A L b. Install the bearing in the connecting rod and cap. c. Install the bearing cap and evenly torque nuts to specifications. Do not turn the crankshaft with the gaging plastic installed. d. Remove the bearing cap and using the scale on the gaging plastic envelope, m easure the gaging plastic width at the widest point (fig.6A4-41). 6. If the clearance exceeds specifications, select a new, correct size, bearing and rem easure the clearance. Be sure to check w hat size bearing is being removed in order to determ ine proper replacem ent size bearing. If clearance cannot be brought to within specifications, the crankpin will have to be ground undersize. If the crankpin is already at m axim um undersize, replace crankshaft. 7. Coat the bearing surface with oil, install the rod cap and torque nuts to specifications. 8. W hen all connecting rod bearings have been installed tap each rod lightly (parallel to the crankpin) to make sure they have clearance. 9. M easure all connecting rod side clearances (see speci­ fications) between connecting rod caps (fig. 6A 4-42). M AIN BEARINGS M ain bearings are of the precision insert type and do not utilize shims for adjustm ent. If clearances are found to be excessive, a new bearing, both upper and lower halves, will be required. Service bearings are available in standard size and .001", .002 ", .009 " ,.0 1 0 " and .020 " undersize. Selective fitting of both rod and m ain bearing inserts is necessary in production in order to obtain close tolerances. For this reason you may find one half of a standard insert with one half of a .001" undersize insert which will decrease the clearance .0005 " from using a full standard bearing. Fig. 6A4-41 --Measuring Gaging Plastic S/ALL BLOCK 6A4-25 clearance can be m easured between th lower bearing and jo u rn al. If the engine is to rem ain * the vehicle, the cran k sh aft m ust be supported upwail to remove any clearance from the upper bearing. The ttal clearance can then be m easured between the lower bearig and journal. To assure the proper seating of th crankshaft, all bearing cap bolts should be at their speified torque. In addition, preparatory to checking fit of beamgs, the surface of the crankshaft journal and bearing shoul-be wiped clean of oil. 1. W ith the oil pan and oil pum p removei and starting with the rear main bearing, remove bering cap and wipe oil from journal and bearing cap. 2. Place a piece of gaging plastic the full vidth of the bearing (parallel to the crankshaft) on theournal (fig. 6A4-43). Do not rotate the crankshaft while the gagig plastic is between the bearing and journal. Fig. 6A4-42--Measuring Connecting Rod Side Clearance W hen a production c ra n k sh a ft can n ot be precision fitted by this method, it is then ground .009" undersize ON ONLY THOSE MAIN JOURNALS THAT CANNOT BE PROPERLY FITTED. ALL JOURNALS W ILL NOT NECESSARILY BE GROUND. A .009" undersize bearing or .010" undersize bearing will then be used for precision fitting in the same m anner as previously described. Identification of a reground c ra n k sh a ft is by the following: • The crankshaft throw will be stam ped on one side of the undersize journal with " 9 " , along with a large spot of green paint. • The main bearing cap will be painted light green on each side of the affected journal. If, for any reason, m ain bearing caps are replaced, shimm ing may be necessary. L am inated shims for each cap are available for service. Shim requirem ent will be determ ined by bearing clearance. 3. Install the bearing cap and evenly torque the-etaining bolts to specifications. Bearing cap M U ST b»torqued to specifications in order to assure proper eading. V ariations in torque affect th e com pressio. of the plastic gage. 4. Remove bearing cap. The flattened gaging platic will be found adhering to either the bearing shell or jurnal. 5. On the edge of gaging plastic envelope thee is a graduated scale which is correlated in thousanths of an inch. W ithout removing the gaging plastic, m asure its compressed width (at the widest point) wih the graduations on the gaging plastic envelope (fig.6A444). N orm ally main bearing journals wear evenly an are not out-of-round. However, if a bearing is being itted to an out-of-round (.001 " m ax.), be sure to fit tcthe m axim um diam eter of the journal: If the bearig is Inspection In general, the lower half of the bearing (except # 1 bearing) shows a g reater wear and the most distress from fatigue. If upon inspection the lower half is suitable for use, it can be assumed th a t the upper half is also satisfactory. If the lower half shows evidence of wear or dam age, both upper and lower halves should be replaced. N E V E R R E PL A C E O N E H A L F W IT H O U T R E P L A C IN G T H E O T H E R H A L F. Checking Clearance To obtain the most accurate results with "P lastigage" (or its equivalent) a wax-like plastic m aterial which will compress evenly between the bearing and journal surfaces w ithout dam aging either surface, certain precautions should be observed. If the engine is out of the vehicle and upside down, the crankshaft will rest on the upper bearings and the total Fig. 6A4-43--Gaging Plastic on Journal LIG H T T R U C K SERVICE M A N U A L 6A4-26 SMALL BLOC 7. A standard, .001" or .002" undersize bearing may produce the proper clearance. If not, it will be neces­ sary to regrind the crankshaft journal for use with the next undersize bearing. A fter selecting new bearing, recheck clearance. 8. Proceed to the next bearing. A fter all bearings have been checked rotate the crankshaft to see th at there is no excessive drag. W hen checking # 1 main bearing, loosen accessory drive belts so as to prevent tapered reading with plastic gage. 9. M easure crankshaft end play (see specifications) by forcing the crankshaft to the extrem e front position. M easure at the front end of the rear m ain bearing with a feeler gage (fig. 6A4-45). 10. Install a new rear main bearing oil seal in the cylinder block and main bearing cap. Replacement M ain bearings m ay be replaced w ith or w ithout removing the crankshaft. With Crankshaft Removal Fig. 6A4-44--Measuring Gaging Plastic fitte to the m inim um diam eter and the journal is outof-rund .001", interference between the bearing and jounal will result in rap id bearing failure. If the flatened gaging plastic tapers toward the middle or en6, there is a difference in clearance indicating taper, lo\ spot or other irregularity of the bearing or journal. Bfsure to m easure the journal with a m icrom eter if the fUtened gaging plastic indicates m ore th an .001" dference. 6. I the bearing clearance is within specifications, the baring insert is satisfactory. If the clearance is not nth in specifications, replace the insert. Always replace >oth upper and lower inserts as a unit, if a new bearing cap is being installed and clearance is less than .0 0 1 ", inspect for burrs or nicks; if none are found then install shims as required. 1. Remove and inspect the crankshaft. 2. Remove the main bearings from the cylinder block and main bearing caps. 3. C oat bearing surfaces of new, correct size, m ain bearings with oil and install in the cylinder block and main bearing caps. 4. Install the crankshaft. Without Crankshaft Removal 1. W ith oil pan, oil pum p and sp ark plugs rem oved, remove cap on main bearing requiring replacem ent and remove bearing from cap. 2. Install a main bearing removing and installing tool in oil hole in crankshaft journal. If such a tool is not availale, a cotter pin may be bent as required to do the job. 3. R otate the crankshaft clockwise as viewed from the front of engine. This will roll upper bearing out of block. 4. Oil new selected size upper bearing and insert plain (unnotched) end between crankshaft and indented or notched side of block. R otate the bearing into place and remove tool from oil hole in crankshaft journal. 5. Oil new lower bearing and install in bearing cap. 6. Install main bearing cap with arrows pointing toward front of engine. 7. Torque all main bearing caps E X C E P T T H E R E A R M A IN C A P to specifications. Torque rear main bear­ ing cap to 10-12 lb. ft. (14-16N -m ) then tap end of crankshaft, first rearw ard then forward with a lead ham m er. This will line up re a r m ain bearing and crankshaft thrust surfaces. R etorque all main bearing caps to specifications. OIL SEAL (REAR MAIN) Replacement Fig. 6A4-45--Measuring Crankshaft End Play LIG H T T R U C K SERVIC E M A N U A L • ALW AYS REPLA CE TH E LO W E R SE A L AS A U N IT . U PPER AND SMALL BLOCK 6A4-27 until it protrudes far enough to be removed with pliers (fig. 6A4-48). .004 SHIM STOCK / — 1 / 2 —► 1 I t — h I - .............. ' 11/64 Fig. 6A4-46--Oil Seal Installation Tool 4. Clean all sealant and foreign m aterial from cylinder case bearing cap and crankshaft, using a non-abrasive cleaner. 5. Inspect com ponents for nicks, scratches, burrs and machining defects at all sealing surfaces, case assembly and crankshaft. 6. Coat seal lips and seal bead with light engine oil - keep oil off seal m ating ends. 7. Position tip of tool between crankshaft and seal seat in cylinder case. 8. Position seal between crankshaft and tip of tool so that seal bead contacts tip of tool. M ake sure th at oil-seal lip is positioned tow ard front of engine (fig. 6A4-49). 9. Roll seal around crankshaft using tool as a "shoe­ horn" to protect seal bead from sharp corner of seal seat surface in cylinder case. Installation tool must remain in position until seal is properly positioned with both ends flush with block. 10. Remove tool, being careful not to withdraw seal. 11. Install seal half in bearing cap, again using tool as a "shoe-horn", feeding seal into cap using light pressure with thum b and finger. Fig. 6A4-47--Removing Oil Seal - Lower Half DUST SEAL Fig. 6A4-49-Crankshaft Oil Seal - Rear Main Fig. 6A4-48--Removing Oil Seal - Upper Half The rear main bearing oil seal can be replaced (both halves) w ithout removal of the crankshaft. Extrem e care should be exercised when installing this seal to protect the sealing bead located in the channel on the outside diam eter of the seal. An installation tool (fig. 6A4-46) m ust be used to protect the seal bead when positioning seal as follows: 1. W ith the oil pan and oil pum p removed, remove the rear m ain bearing cap. 2. Remove oil seal from the bearing cap by prying from the bottom with a small screw driver (fig. 6A4-47). 3. To remove the upper half of the seal, use a small ham m er to tap a brass pin punch on one end of seal APPLY SEALANT TO SHADED AREAS ONLY Fig. 6A4-50--Sealing Bearing Cap LIGHT T R U C K SERVICE M A N U A L 6A4-28 SMALL BLOCK 12. Install bearing cap to case with sealant applied to the cap-to-case interface being careful to keep sealant off the seal split line (fig. 6A4-50). 13. Install the rear m ain bearing cap (with new seal) and torque to 10-12 lb. ft. (14-16N -m ). T ap end of crank­ shaft rearw ard then forw ard with lead ham m er. This will line up thru st surfaces. Retorque bearing cap to specifications. PRESS CONNECTING ROD AND PISTON ASSEMBLIES -PISTON PIN REMOVER J-24086-8 Removal 1. Remove oil pan, oil pum p and cylinder head as pre­ viously outlined. 2. For the cylinder being serviced turn crankshaft until piston is a t the bottom of the stroke. Place a cloth on top of the piston. 3. Use a ridge ream er to remove any ridge an d /o r deposits from the upper end of the cylinder bore. 4. Turn crankshaft until piston is at top of stroke and remove cloth and cuttings. 5. Remove connecting rod cap and install Tool J-5239 (3/ 8 " ) on studs. Push connecting rod and piston assembly out of top of cylinder block (fig. 6A 4-51). It will be necessary to turn the crankshaft slightly to disconnect some of the connecting rod and piston assemblies and push them out of the cylinder. FIXTURE SUPPORT ASSEMBLY J-24086-20 Disassembly Fig. 6A4-52--Removing Piston Pin 1. Remove connecting rod bearings from connecting rods and caps. If bearings are being reused, place them in a rack so they m ay be reinstalled in their original rod and cap. 2. Remove piston rings by expanding and sliding them off the pistons. 3. Place connecting rod and piston assem bly on Tool J-24086-20. U sing an arb o r press and piston pin remover, J-24086-8, press the piston pin out of connect­ ing rod and piston (fig. 6A4-52). Cleaning and Inspection Connecting Rods W ash connecting rods in cleaning solvent and dry with compressed air. Check for twisted or bent rods and inspect for nicks or cracks. R eplace connecting rods th a t are dam aged. Pistons C lean varnish from piston skirts and pins w ith a cleaning solvent. DO N O T W IR E B R U SH A N Y PA R T O F T H E P IS T O N . Clean the ring grooves with a groove cleaner and make sure oil ring holes and slots are clean. Inspect the piston for cracked ring lands, skirts or pin bosses, wavy or worn ring lands, scuffed or dam aged skirts, eroded areas at top of the piston. Replace pistons th at are dam aged or show signs of excessive wear. Inspect the grooves for nicks or burrs th at might cause the rings to hang up. M easure piston skirt (across center line of piston pin) and check clearance. w Piston Pins Fig. 6A4-51--Removing Connecting Rod & Piston Assembly The piston pin clearance is designed to m aintain adequate clearance under all engine operating conditions. Because of this, the piston and piston pin are a m atched set and not serviced separately. LIG H T T R U C K SERVICE M A N U A L i SMALL BLOCK Inspect piston pin bores and piston pins for wear. Piston pin bores and piston pins m ust be free of varnish or scuffing when being m easured. The piston pin should be m easured w ith a m icrom eter and th e piston pin bore should be m easured with a dial bore gage or an inside m icrom eter. If clearance is in excess of the .001" wear limit, the piston and piston pin assembly should be replaced. Assembly 1. L ubricate piston pin holes in piston and connecting rod to facilitate installation of pin. 2. Place connecting rod in piston and hold in place with piston pin guide and piston pin. Place assembly on fixture and support assembly. 3. Using piston pin installer, J-24086-9, press the piston pin into the piston and connecting rod (fig. 6A4-53). NOTICE: A fter installer hub bottom s on support assem ­ bly, do not exceed 5000 psi pressure, as this could cause structural dam age to the tool. 4. Remove piston and connecting rod assembly from tool and check piston for freedom of movement on piston pin. 6A4-29 ring is a tapered face acting as both a compression and oil control ring. The oil control rings are of three piece type, consisting of two segments (rails) and a spacer. 1. Select rings com parable in size to the piston being used. 2. Slip the compression ring in the cylinder bore; then press the ring down into the cylinder bore about 1/4" (6.5m m ) (above ring travel). Be sure ring is square with cylinder wall. 3. M easure the space or gap between the ends of the ring with a feeler gage (fig. 6A4-54). 4. If the gap betw een the ends of the ring is below specifications, remove the ring and try another for fit. 5. Fit each compression ring to the cylinder in which it is going to be used. 6. If the pistons have not been cleaned and inspected as previously outlined, do so. 7. Slip the outer surface of the top and second com pres­ sion ring into the respective piston ring groove and roll the ring entirely around the groove (fig. 6A4-55) to make sure th at the ring is free. If binding occurs at any point, the cause should be determ ined. If binding is Piston Rings All compression rings are m arked on the upper side of the ring. W hen installing compression rings, make sure the M A R K E D S ID E IS T O W A R D T H E T O P O F T H E P IS T O N . The top ring is chrom e faced, or treated with molybdenum for m axim um life. The second compression Fig. 6A4-54~Measuring Ring Gap Fig. 6A4-53--lnstalling Piston Pin Fig. 6A4-55--Checking Ring in Groove LIG H T T R U C K SERVICE M A N U A L 6A4-30 SMALL BLOCK Fig. 6A4-57--Measuring Ring Groove Clearance caused by ring groove, correct by dressing with a fine cut file. If the binding is caused by a distorted ring, check a new ring. 8. Install piston rings as follows (fig. 6A4-56): a. Install oil ring spacer in groove and insert anti­ rotation tang (where applicable) in drilled hole. b. Hold spacer ends butted and install lower steel oil ring rail with gap properly located. c. Install upper steel oil ring rail with gap properly located. d. Flex the oil ring assem bly to make sure ring is free. If binding occurs at any point the cause should be determ ined. If binding is caused by ring groove, correct by dressing groove with a fine cut file. If binding is caused by a distorted ring, check a new ring. e. Install second compression ring (m anufacturer m ark up) with gaps properly located. f. Install top compression ring (m anufacturer m ark up) with gap properly located. 9. Proper clearance of the piston ring in its piston ring groove is very im portant to provide proper ring action and reduce wear. Therefore, when fitting new rings, the clearances between the surfaces of the ring and groove should be m easured (fig. 6A 4-57). (See Specifications). Installation Cylinder bores m ust be clean before piston installation. This may be accomplished with a hot w ater and detergent wash or with a light honing as necessary. A fter cleaning, the bores should be swabbed several tim es with light engine oil and a clean dry cloth. 1. L ubricate connecting rod bearings and install in rods and rod caps. 2. Lightly coat pistons, rings and cylinder walls with light engine oil. LIG H T T R U C K SERVIC E M A N U A L Fig. 6A4-58--lnstalling Connecting Rod Piston Assembly 3. W ith bearing caps removed, install Tool J-5239 (3 /8 " ) on connecting rod bolts. 4. Install each connecting rod and piston assembly in its respective bore. Install with connecting rod bearing tang slots on side opposite cam shaft. Use Tool J-8037 to compress the rings (fig. 6A4-58). G uide the connect­ ing rod into place on the crankshaft journal with Tool J-5239 ( 3 /8 " ) Use a ham m er handle and light blows to install the piston into the bore. Hold the ring com pres­ sor firmly against the cylinder block until all piston rings have entered the cylinder bore. 5. Remove Tool J-5239. 6. Install the bearing specifications. caps and torque nuts to Be sure to install new pistons in the cylinders for which they were fitted, and used pistons in the cylinder from which they were removed. Each connecting rod and bearing cap should be m arked, beginning at the front of the engine. Cylinders 1,3,5 and 7 are the left bank and, 2 4, 6 and 8 are the right bank. The num bers on the connecting rod and SMALL BLOCK bearing cap m ust be on the sam e side when installed in the cylinder bore. If a connecting rod is ever transposed from one block or cylinder to another, new bearings should be fitted and th e connecting rod should be num bered to correspond with the new cylinder num ber. CYLINDER BLOCK Cleaning and Inspection 1. W ash cylinder block thoroughly in cleaning solvent and clean all gasket surfaces. 2. Remove oil gallery plugs and clean all oil passages. 3. Clean and inspect coolant passages in the cylinder block. 4. Inspect the cylinder block for cracks in the cylinder w alls, coolant ja c k e t, valve lifter bores and m ain bearing webs. 5. M easure the cylinder walls for taper, out-of-round or excessive ridge at top of ring travel. This should be done with a dial indicator. Set the gage so th a t the thrust pin m ust be forced in about 1/4" (6.5m m ) to enter gage in cylinder bore. C enter gage in cylinder and turn dial to " 0 " . Carefully work gage up and down cylinder to determ ine taper and turn it to different points around cylinder wall to determ ine the out-of-round condition. If cylinders were found to exceed specifications, honing or boring will be necessary. Conditioning The perform ance of the following operation is contin­ gent upon engine condition at tim e of repair. If the cylinder block inspection indicated th at the block was suitable for continued use except for out-of-round or tapered cylinders, they can be conditioned by honing or boring. If the cylinders were found to have less than .005" (. 13mm) taper or wear, they can be conditioned with a hone and fitted w ith the high lim it sta n d a rd size piston. A cylinder bore of less then .005" (.13m m ) w ear or taper may not entirely clean up when fitted to a high lim it piston. If it is desired to entirely clean up the bore in these cases, it will be necessary to rebore for an oversize piston. If more than .005" (.13m m ) taper or wear, they should be bored and honed to the sm allest oversize th at will perm it complete resurfacing of all cylinders. W hen pistons are being fitted and honing is not necessary, cylinder bores m ay be cleaned with a hot w ater and d eterg en t wash. A fte r cleaning, th e cylinder bores should be swabbed several tim es with light engine oil and a clean cloth and then wiped with a clean dry cloth. Boring 1. Before using any type boring b ar, th e top of the cylinder block should be filed to remove any dirt or burrs. This is very im portant. If not checked, the boring bar m ay be tilted which would result in the rebored cylinder wall not being a t rig h t angles to the crankshaft. 2. The piston to be fitted should be m easured with a m icrom eter, m easuring at the center of the piston skirt and at right angles to the piston pin. The cylinder should be bored to the sam e diam eter as the piston and honed to give the specified clearance. 6A4-31 3. The instructions furnished by the m anufacturer of the equipm ent being used should be carefully followed. Honing 1. W hen cylinders are to be honed, follow the hone m anufacturer’s recom m endations for the use of the hone and cleaning and lubrication during honing. 2. Occasionally during the honing operation, the cylinder bore should be thoroughly cleaned and the piston selected for the individual cylinder checked for correct fit. 3. W hen finish honing a cylinder bore to fit a piston, the hone should be moved up and down at a sufficient speed to obtain very fine uniform surface finish m arks in a cross-hatch pattern of approxim ately 45° to 65° in­ cluded angle. The finish m arks should be clean but not sharp, free from imbedded particles and torn or folded metal. 4. Perm anently m ark the piston for the cylinder to which it has been fitted and proceed to hone cylinders and fit the rem aining pistons. NOTICE: H andle th e pistons with care and do not attem pt to force them through the cylinder until the cylinder has been honed to correct size as this type piston can be distorted through careless handling. 5. Thoroughly clean the bores with hot water and deter­ gent. Scrub well with a stiff bristle brush and rinse thoroughly with hot w ater. It is extremely essential th at a good cleaning operation be performed. If any of the abrasive m aterial is allowed to rem ain in the cylinder bores, it will rapidly wear the new rings and cylinder bores in addition to the bearings lubricated by the contam inated oil, the bores should be swabbed and then wiped with a clean dry cloth. C ylinder should not be cleaned with kerosene or gasoline. Clean the rem ainder of the cylinder block to remove the excess m aterial spread during the honing operation. Piston Selection 1. C heck U S E D piston to cylinder bore clearan ce as follows: a. M easure the "C y lin d er Bore D ia m e te r" w ith a telescope gage |2 - l / 2 " (64m m ) from top of cylinder bore]). b. M easure the "P iston D iam eter" (a t sk irt across center line of piston pin). c. S ubtract piston diam eter from cylinder bore diam e­ ter to determ ine " Piston to Bore C learance ". d. Locate piston to bore clearance on Piston Selection C hart and determ ine if piston to bore clearance is in the acceptable range. 2. If used piston is not acceptable, determ ine if a new piston can fit cylinder bore. 3. If cylinder bore m ust be reconditioned, m easure new piston diam eter (across center line of piston pin) then hone cylinder bore to correct clearance. 4. M ark the piston to identify the cylinder for which it was fitted. LIG H T T R U C K SERVICE M A N U A L 6A4-32 SMALL BLOCK OIL FILTER BYPASS VALVE Inspection and Replacement W ith the oil filter removed, check the spring and fibre valve for operation. Inspect for a cracked or broken valve. If replacem ent is necessary, the oil filter adapter and bypass valve assembly m ust be replaced as an assembly. Clean valve cham ber in cylinder block thoroughly. Torque retain­ ing screws to specifications. ENGINE ASSEMBLY Removal ("G " V an ) 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. Disconnect battery cables at battery. D rain cooling system. Remove coolant reservoir bottle. Remove grille, upper radiator support and lower grille valance. Disconnect radiator hoses at radiator. • If equipped with autom atic transm ission, remove cooler lines from radiator. • If equipped with A /C , evacuate system and remove condenser. Remove A /C vacuum reservoir. Remove w asher ja r and bracket. Remove radiator to rad iato r support attaching brackets and remove radiato r and shroud. If equipped with P /S , remove pum p and lay aside. Remove engine cover. Remove air cleaner air stove pipe. Remove accelerator cable from carburetor and remove carburetor. Disconnect engine wiring harness from connection on firewall. Disconnect heater hoses a t engine. Remove therm ostat housing. Remove oil fill pipe. If equipped w ith cruise control, rem ove servo and bracket and transducer. Raise vehicle. D isconnect ex h au st pipe from exhaust m anifold flanges. Remove propshaft; plug transm ission end. Disconnect transm ission shift linkage and speedometer cable. Disconnect fuel hose from fuel pump. Remove transm ission m ount bolts. Remove engine m ount bracket to fram e bolts. Drain crankcase. Remove engine m ount "th ro u g h " bolts. Raise engine slightly and remove engine m ounts. Block up engine with wood between oil pan and crossm ember. Lower vehicle and install lifting tool. Remove engine/transm ission assembly. Installation ("G " Van) 1. Place engine/transm ission assembly into vehicle. Sup­ port engine with blocks of wood between the oil pan and crossmembers. LIG H T T R U C K SERVIC E M A N U A L 2. Raise vehicle and install engine m ounts. R etain by inserting engine mount "th ro u g h " bolts. 3. Raise engine slightly, remove wooden blocks and lower engine onto mounts. 4. Install engine mount bracket to fram e bolts. Torque to specifications. 5. Install transm ission m ount bolts. T orque to specifications. 6. Connect fuel tank line and return line to fuel pump. 7. Connect transmission shift linkage and speedom eter cable. 8. Install propshaft. 9. 10. 11. 12. Connect exhaust pipe to exhaust manifold flanges. Lower vehicle. Connect heater hoses. Connect engine wiring harness. 13. Using a new gasket, install carburetor. Connect accel­ erator cable. 14. Install radiator. Install radiator to radiator support attaching brackets. • If equipped with autom atic transm ission, connect cooler lines to radiator. • If equipped with A /C , install condenser to radiator support. 15. Connect radiator hoses to radiator. 16. Install grille cross brace and grille. 17. Fill cooling system. 18. Fill crankcase with oil. • If equipped with A /C , m ount compressor, connect hosing and charge system. 19. Connect battery cables and start engine. Check ignition tim ing and adjust carburetor if necessary. 20. Install air cleaner and engine cover. Removal (CK Series) 1. Disconnect battery cables at battery. 2. D rain cooling system. 3. Remove air cleaner. 4. Remove all accessory drive belts. 5. Remove fan and w ater pum p pulley. 6. Disconnect upper and lower radiator hoses at engine. 7. Disconnect heater hoses at engine. • If equipped with autom atic transm ission, disconnect cooler lines a t radiator. 8. Remove radiator and shroud. 9. Disconnect accelerator linkage and detent linkage, if so equipped, from carburetor. 10. If A /C equipped, remove com pressor from engine and lay aside. 11. If power steering equipped, remove pum p from engine and lay aside. 12. Remove engine wiring harness from engine. 13. Disconnect fuel line at fuel pump. 14. Disconnect all vacuum lines from intake manifold. 15. Raise vehicle. 16. D rain crankcase. SMALL BLOCK 17. D isconnect ex h au st pipe from ex haust m anifold flanges. • ’K ’ m odels w ith au to m atic transm ission, rem ove stru t rods at motor mounts. 6A4-33 CRANKSHAFT The crankshaft can be removed while the engine is disassembled for overhaul, as previously outlined, or without complete disassembly as outlined below. 18. Rem ove flywheel or convertor splash shield, as applicable. Removal 19. Disconnect wiring along right pan rail. 20. Disconnect wiring at starter and remove starter. 21. Disconnect wiring for gas gage. 22. If equipped w ith au to m atic transm ission, remove convertor to flex plate attaching bolts. 23. Support transm ission. 24. Remove bell housing to engine retaining bolts. 25. Remove lower engine m ount bracket to fram e bolts. 26. Lower vehicle. 27. Remove vehicle hood. 28. A ttach engine lifting device. 29. Remove engine. Installation (CK Series) 1. Place engine in vehicle. 2. Raise vehicle. 3. Install engine m ount bracket to fram e bolts. 4. Install bell housing to engine retaining bolts. Remove transm ission support. 5. If equipped with autom atic transm ission, install con­ vertor to flex plate attaching bolts. 6. In stall flywheel applicable. or convertor splash shield, as 7. Connect wiring for gas gage. 8. Install starter. Connect wiring. 9. Install engine wiring harness along right pan rail. 10. Connect exhaust pipe to exhaust m anifold flanges. 11. Lower vehicle. 12. Connect all vacuum lines to intake manifold. 13. Connect fuel line a t fuel pump. 14. Install engine wiring harness to engine. 1. W ith the engine removed from the vehicle and the transm ission an d /o r clutch housing removed from the engine, m ount engine in stand and clam p securely. 2. Remove the oil dip stick and oil dip stick tube, (if applicable). 3. Remove the sta rtin g m otor, clutch assem bly (if equipped) and flywheel. 4. Remove the spark plugs. 5. Remove crankshaft pulley and torsional dam per. 6. Remove oil pan and oil pump. 7. Remove crankcase front cover, and if so equipped, remove tim ing chain and cam shaft sprocket. 8. Check the connecting rod caps for cylinder num ber identification. If necessary, m ark them . 9. Remove the connecting rod caps and push the pistons to top of bores. 10. Remove main bearing caps and lift crankshaft out of cylinder block. 11. Remove rear main bearing oil seal and main bearings from cylinder block and main bearing caps. Cleaning and Inspection 1. W ash crankshaft in solvent and dry with compressed air. 2. M easure dim ensions of m ain bearing jo u rn als and crankpins with a m icrom eter for out-of-round, taper or undersize. (See Specifications.) 3. Check crankshaft for run-out by supporting a t the front and rear main bearings journals in "V " blocks and check at the front and rear interm ediate journals with a dial indicator. (See Specifications.) 4. R eplace or recondition the cra n k sh a ft if out of specifications. 15. If power steering equipped, install pum p on engine. 16. If A /C equipped, install com pressor on engine. 17. Connect accelerator linkage and detent linkage, if so equipped, to carburetor. 18. Install radiator. • If equipped with autom atic transm ission, connect cooler lines to radiator. 19. Connect heater hoses to engine. 20. Connect radiator hoses to engine. 21. Install w ater pum p pulley and fan to w ater pump. 22. Install accessory drive belts. A djust to specifications. 23. Fill cooling system. 24. Fill crankcase. 25. Connect battery cables and start engine. Check timing and carburetor adjustm ent and adjust if necessary. 26. Install air cleaner and vehicle hood. Fig. 6A4-59--Sprocket or Gear Replacement LIG H T T R U C K SERVICE M A N U A L 6A4-34 SMALL BLOCK SPROCKET OR GEAR REPLACEMENT (REFER TO FIG. 6A4-59) • Rem ove c ra n k sh a ft sprocket using Tool J-5825, install using Tool J-5590. Installation 1. Install rear m ain bearing oil seal in cylinder block and rear main bearing cap grooves. Install with lip of seal toward front of engine. W here seal has two lips install lip with helix tow ards front of engine. 2. Lubricate lips of seal with engine oil. Keep oil off parting line surface. 3. Install m ain b earings in cylinder block and m ain bearing caps then lubricate bearing surface with engine oil. 4. Install crankshaft, being careful not to dam age bearing surfaces. 5. Apply a thin coat of brush-on type oil sealing com­ pound to block m ating su rface and corresponding surface of cap only (fig. 6A4-60). Do not allow sealant on crankshaft or seal. 6. Install main bearing caps with arrows pointing toward front of engine. 7. T orque all except re a r m ain bearing cap bolts to specifications. Torque rear m ain bearing cap bolts to 10-12 lbs. ft. (14-16 N -m ) then tap end of crankshaft, first rearw ard then forw ard with a lead ham m er. This will line up rear main bearing and crankshaft thrust LIG H T T R U C K SERVICE M A N U A L surfaces. R etorque all m ain bearing cap bolts to specifications. 8. M easure crankshaft end play with a feeler gage. Force crankshaft forward and m easure clearance between the front of the rear main bearing and the crankshaft thrust surface. 9. Install flywheel and torque to specifications. A wood block placed between the crankshaft and cylinder block will prevent crankshaft from rotating. • Align dowel hole in flywheel with dowel hole in crankshaft. On vehicles equipped with autom atic transm issions, install flywheel with the converter attaching pads towards transm ission. APPLY SEALANT TO SHADED AREAS ONLY Fig. 6A4-60--Sealing Bearing Cap 5.0 (F) 5.0 (G) 5.0 (H) L ITR E (* ) LF3 RPO LG9 CLEARANCE .001 M A X . S E R V IC E .0008-.001 6 IN T E R F E R E N C E F IT IN R O D LS9 /L T 9 LE9 •00025-.00035 P R O D U C T IO N 5.7 (L) 5.7 (M) 3.736 BORE CRANKSHAFT 4.000 #1 2.44 84 -2 .4 4 93 3.480 STROKE 8.6: i j 8.5: 1* 9.2:1 I 8.2:1 C O M P R E S S IO N R A T IO j 8.3:1 D IA M E T E R # 2 -3 -4 1-8-4-3-6-5-7-2 F IR IN G O R D E R LS9/LT9 .9270-.9273 D IA M E T E R 90° V-8 G A S O LIN E TYPE D IS P L A C E M E N T LF3.LG9,LE9, PISTON PIN GENERAL DATA: #5 M A IN JO UR NAL C YLINDER BORE: 2.4481 -2 .4 4 90 2.4479 -2 .4 4 88 .0002 M A X . P R O D U C T IO N 1A r t H 3.7350-3.7385 D IA M E T E R O U T OF ROUND TAPER 3.9995-4.0025 P R O D U C T IO N .001 M A X . S E R V IC E .002 M A X . PRODUC­ T IO N THRUST S ID E .0005 M A X . R E L IE F S ID E .001 M A X . O UT OF ROUND .0002 M A X . P R O D U C T IO N .001 M A X . S E R V IC E #1 M A IN B E A R IN G C L E A R A N I: e #5 S E R V IC E #1 .0 0 1 .0 0 1 5 P R O D U C T IO N .0007-.0017 S E R V IC E .0027 M A X . .0011-.0023 .001 7-.0032 # 2 -4 .0 0 1 .0 0 2 5 # 5 .0 0 2 5 .0035 .0 0 2 .0 0 6 CRANKSHAFT END PLA Y PISTON: .0 0 8 .0 0 2 0 #2-3-4 P R O D U C T IO N .001 M A X . S E R V IC E .001 M A X . S E R V IC E 2.0988-2.0998 D IA M E T E R CLEARANCE G ROOVE CLEAR­ ANCE PRODUC­ T IO N R S S I O N 2N D PRODUC­ T IO N .001 2-.0032 HI L IM IT PR O D U C TIO N TO P .0 1 0 .0 2 0 2N D .0 1 0 .0 2 5 S E R V IC E GROOVE CLEAR­ ANCE O U T OF ROUND S E R V IC E GAP .001 2 .0 0 3 2 P R O D U C T IO N S E R V IC E P R O D U C T IO N GAP S E R V IC E HI L IM IT PR O D U C TIO N + .001 + .010 .0013-.0035 P R O D U C T IO N .0030 S E R V IC E .008-.014 CAMSHAFT L O B E L IF T ± 002 + .001 .01 5-.055 HI L IM IT PR O D U C TIO N .001 M A X . S E R V IC E R O D S ID E C L E A R A N C E .002-.007 HI L IM IT P R O D U C TIO N R O D B E A R IN G CLEARANCE .0005 P R O D U C T IO N + .010 IN T A K E .2484 .2600 EXHAUST .2667 .2733 J O U R N A L D IA M E T E R 1.8682-1.8692 CAM SHAFT END PLAY .0 0 4.0 1 2 SMALL BLOCK O I L TO P .001 M A X . S E R V IC E C R A N K P IN PISTON RING: C O M p .0005 P R O D U C T IO N * VIN D esignation 6A4-35 TRUCK 6A4-36 LIGHT MANUAL LF3. ROCKER A R M R A T IO EXHAUST FACE A N G L E (IN T . & EXH.) 45 SEAT A N G L E (INT. & EX H.) 46 .002 M AX. 1/32-1/16 IN T A K E 1/1 6-3/32 EXHAUST STEM CL E A R A N C E P R O D U C T IO N IN T . .0010-.0027 EX H .0010-.0027 SERVICE HI L IM IT + .001 IN T A K E + .002 EXHAUST FREE L E N G T H 2.03 O z CO VALVE SPRING (O UTE R) LT9 ONE TURN DOWN FROM ZERO LASH IN T A K E SEAT W ID T H LS9; 1.50:1 SEAT R U N O U T n 3I n > LE9 H Y D R A U LIC L IF T E R VALVE LASH LG9L J L PRESSURE LBS. @ IN. CLOSED 76-84 @ 1.70 INT. @ 1.61 EXH. OPEN 194-206 @ 1.25 INT. @ 1.16 EXH. IN S T A L L E D H E IG H T 1-23/32 INT. 1-19/32 EXH. ± 1/32" FREE L E N G T H DAMPE R APPROX. # OF COILS 1.86 80 LB. IN. CRANKCASE FRONT C O V E R ........................... 80 LB. IN. FLYW H EEL HOUSING C O V E R ........................ O IL FILTE R BYPASS V A L V E ........................... 80 LB. IN. O IL PAN (TO CRANKCASE) (1 /4 -2 0 ).............. 80 LB. IN. O IL PUMP C O V E R ................................................ 80 LB. IN. ROCKER ARM C O V E R ........................................ 45 LB. IN. CAM SHAFT S P R O C K E T ...................................... 20 LB. FT. O IL PAN TO CRANKCASE (5 /1 6 -1 8 )..............165 LB. IN. CLUTCH PRESSURE P L A T E .............................. 30 LB. FT. DISTR IBU TO R CLAMP . . . ................................. 25 LB. FT. FLYW H EEL H O U S IN G ........................................ 30 LB. FT. M A N IF O LD (E X H A U S T )......................................20 LB. F T .i M A N IF O LD (IN L E T ).............................................. 30 LB. FT. WATER O U T L E T ................................................... 30 LB. FT. WATER P U M P ......................................................... 30 LB. FT. CONNECTING ROD CAP...................................... 45 LB. FT. C Y LIN D E R H E A D ................................................ 65 LB. FT. M AIN BEAR IN G C A P ................................ .. 80 LB. FT.2 65 LB. FT. O IL P U M P ................................................................ F L Y W H E E L .............................................................. 60 LB. FT. T O R S IO N A L D A M P E R ........................................ 60 LB. FT. TEM PER ATU RE SENDING U N IT ...................... 20 LB. FT. O IL F I L T E R ........................................................... 25 LB. FT. O IL PAN D R A IN PLUG ........................................ 20 LB. FT. SPARK P L U G ........................................................ 17-27 LB. FT. 1 Inside bolts on 5.7 (L) 30 LB. FT. 2 Intermediate outer bolts are 70 LB. FT. SMALL BLOCK SERVICE T O R Q U E S P E C IF IC A T IO N S VA LV E SYSTEM MARK IV 6A5-1 SECTION 6A5 7.4 L (W) V-8 - RPO LE8 Contents G eneral D escription....................................................... Engine L ubrication........................................................ On Vehicle S erv ice........................................................ Engine M o u n ts ............................................................. Intake M anifold............................................................ E xhaust M anifold........................................................ Rocker A rm C o v er...................................................... Valve M echanism ........................................................ Valve Stem Oil Seal and/or Valve S p rin g .................................................................... Valve L ifte rs................................................................. Cylinder Head A ssem bly.......................................... Rocker A rm S tu d s....................................................... Valve G uide Bores....................................................... Valve S e a ts .................................................................... V alves.............................................................................. Torsional D am per........................................................ 6A5-1 6A5-4 6A5-4 6A5-9 6A5-9 6A5-10 6A5-10 6A5-11 6A5-11 6A5-12 6A5-13 6A5-16 6A5-16 6A5-16 6A5-16 6A5-16 Crankcase Front C o v e r.............................................. Oil Seal (Front C ov er)............................................... C a m s h a ft....................................................................... C am shaft B earings....................................................;. Oil P a n ............................................................................ Oil Pum p........................................................................ Connecting Rod B e a rin g s......................................... M ain B earings.............................................................. Oil Seal (R ear M a in )................................................. Connecting Rod Piston A sem blies.......................... Cylinder B lo c k ............................................................. Oil Filter ByPass V alve.............................................. Engine A ssem bly......................................................... C ra n k sh a ft..................................................................... Sprocket or G ear R eplacem ent................................ Specifications................................................................... 6A5-17 6A5-18 6A5-18 6A5-19 6A5-20 6A5-20 6A5-21 6A5-22 6A5-24 6A5-25 6A5-28 6A5-29 6A5-29 6A5-30 6A5-30 6A5-31 GENERAL DESCRIPTION (FIG. 6A5-1 & 6A5-2) CYLINDER BLOCK The cylinder block is made of cast iron and has 8 cylinders arranged in a "V " shape with 4 cylinders in each bank. Five main bearings support the crankshaft which is retained by bearing caps th at are m achined with the block for proper alignm ent and clearnances. Cylinders are com­ pletely encircled by coolant jackets. tim ing chain which in turn drives the cam shaft through an alum inum and nylon sprocket. Cam lobes are ground, hardened and tapered with the high side toward the rear. This, coupled with a spherical face on the lifter, causes the valve lifters to rotate. C am shaft bearings are lubricated through oil holes which intersect the main oil gallery. The main oil gallery is rifle drilled down the left side of the cylinder case. CYLINDER HEAD The cast iron cylinder heads have individual intake and exhaust ports for each cylinder. Valve guides are integral, and rocker arms are retained on individual threaded studs. CRANKSHAFT AND BEARINGS The crankshaft is cast nodular iron, and is supported by five main bearings. N um ber five bearing is the end thrust bearing. All main bearings are lubricated from oil holes th at connect to the main oil gallery. This runs along the left side of the cylinder case, ju st above the oil pan rail. Two additional galleries supply oil to the valve lifters. A torsional dam per on the forward end of the crank­ shaft dampens any engine torsional vibrations. CAMSHAFT AND DRIVE The cast iron cam shaft is supported by five bearings and is chain driven. A steel crankshaft gear drives the PISTONS AND CONNECTING RODS The pistons are m ade of cast alum inum alloy using two compression rings and one oil control ring. Pins are C hro­ mium steel and have a floating fit in the pistons They are retained in the connecting rods by a press fit. Connecting rods are m ade of forged steel. Full pressure lubrication is directed to the connecting rods by drilled oil passages from the adjacent main bearing journal. Oil holes at the connecting rod journals are located so th at oil is supplied to give m axim um lubrication just prior to full bearing load. VALVE TRAIN A very simple ball pivot-type train is used. Motion is transm itted from the cam shaft through the hydraulic lifter and push rod to the rocker arm. The rocker arm pivots on its ball and transm its the cam shaft motion to the valve. The rocker-arm ball is retained by a nut. LIG H T T R U C K SERVICE M A N U A L 6A5-2 MARK IV CO VER DISTRIBUTO R STUD NUT BALL CLAMP OUTLET ARM STUD GASKE T G U ID E THERMOSTAT M A N IFO L D SPRING BO L T SEAL SHIM BOLT ROTATOR PLUG GSKT HEAD G ASKE T BOLT M A N IFO L D VALVE L IF T E R VALVE Fig. 6A5-1--Engine Upper End LIG H T T R U C K SERVIC E M A N U A L MARK IV 6A5-3 PISTON BOLT BEARING SET CAMSHAFT FLYWHEEL CHAIN GEAR PLUG WASHER BOLT (5/16-18 x 3/4) BOLT PUMP GASKET GASKET BLOCK BOLT (3/8-16 x 1 3/4) CRANKSHAFT ADAPTER WASHER ( 5 / 1 6 ) ^ ' GASKET PRO LOC A COVER SEAL EXTENSION CONNECTOR SEAL GEAR SHAFT FILTER DAMPER BOLT PUMP WASHER BOLT BOLT SCREEN BOLT GASKET SEAL GASKET BOLT BOLT PLUG Fig. 6A5-2--Engine Lower End LIG H T TR U C K SERVICE M A N U A L 6A5-4 MARK IV HYDRAULIC VALVE LIFTERS INTAKE MANIFOLD Hydraulic Valve Lifters are used to keep all parts of the valve train in constant contact. The intake manifold is of cast iron double level design for efficient fuel distribution. The carburetor pad is centrally located with a passage running underneath the pad (E.F.E.) through which exhaust gases are forced to prom ote faster fuel vaporization when the engine is cold. The hydraulic lifter assembly consists of: the lifter body, which rides in the cylinder block boss, a plunger, a push rod seat, a m etering valve, a plunger spring, a check ball and spring, a check ball retainer and a push rod seat retainer. W hen the lifter is riding on the low point of the cam, the plunger spring keeps the plunger and push rod seat in contact with the push rod. W hen the lifter body begins to ride up the cam lobe, the check ball cuts off the transfer of oil from the reservoir below the plunger. The plunger and lifter body then rise as a unit, pushing up the push rod and opening the valve. As the lifter body rides down the other side of the cam, the plunger follows with it until the valve closes. The lifter body continues to follow the cam to its low point, but the plunger spring keeps the plunger in contact with the push rod. The ball check valve will then move off its seat and the lifter reservoir will rem ain full. EXHAUST MANIFOLDS Two cast iron exhaust manifolds are used to direct exhaust gases from the combustion cham bers to the exhaust system. The right hand side manifold receives a heat shield th at is used to route heated air to the air cleaner for better fuel vaporization. COMBUSTION CHAMBERS C om bustion C ham bers are cast to insure uniform shape for all cylinders. Spark plugs are located between the intake and exhaust valves. The contoured wedge shape of the com bustion cham ber minimizes the possibility of detonation, facilitates breath ­ ing, and provides swirling turbulence for smooth, complete combustion. ENGINE LUBRICATION Full pressure lubrication through a full flow oil filter, is furnished by a gear-type oil pump. The distributor, driven by a helical gear on the cam shaft, drives the oil pump. The main oil gallery feeds oil, through drilled passages, to the cam shaft and crankshaft to lubricate the bearings. The valve lifter oil gallery feeds the valveiifters which, through hollow push rods, feed the individually mounted rocker arm s (fig. 6A5-3). ON VEHICLE SERVICE Fig. 6A5-4--"P" Series Engine Mount Bracket LIG H T T R U C K SERVICE M A N U A L MARK IV 6A5-5 FUEL PUMP PUSH ROD OILING CRANKCASE AND CRANKSHAFT OILING VALVE MECHANISM OILING Fig. 6A5-3--"Mark IV" Engine Lubrication LIG H T T R U C K SERVICE M A N U A L 6A5-6 MARK IV MANUAL TRANSMISSION ALL TURBO HYDRA-MATIC 400 (EXCEPT MOBILE HOME CHASSIS) WITH PROPELLER SHAFT PARKING BRAKE WITHOUT PROPELLER SHAFT PARKING BRAKE ALL MANUAL TRANSMISSION ALL TURBO HYDRA-MATIC 350 ALL MOBILE HOME CHASSIS WITHOUT PROPELLER SHAFT PARKING BRAKE AUTOMATIC TRANSMISSION WITH PROPELLER SHAFT PARKING BRAKE Fig. 6A5-5--"P" Series Engine Rear Mount LIG H T T R U C K SERVIC E M A N U A L MARK IV 6A5-7 Fig. 6A5-6--"P" Series Engine Front Mount LIG H T T R U C K SERVICE M A N U A L 6A5-8 MARK IV Fig. 6A5-7--"C" Series Engine Mounts LIG H T T R U C K SERVIC E M A N U A L MARK IV ENGINE MOUNTS E ngine m ounts (fig. 6A 5-4 - 6A 5-7) are the nonad ju stab le type and seldom req u ire service. Broken or d e te rio ra ted m ounts should be replaced im m ediately, because of the added strain placed on other m ounts and drive line components. Checking Engine Mounts Front Mount Raise the engine to remove weight from the m ounts and to place a slight tension in the rubber. Observe both mounts while raising engine. If an engine m ount exhibits: a. H ard rubber surface covered with heat check cracks; b. R ubber separated from a m etal plate of the mount; or c. R ubber split through center R eplace the m ount. If th e re is relativ e m ovem ent between a m etal plate of the m ount and its attaching points, lower the engine on the m ounts and tighten the screws or nuts attaching the mount to the engine, fram e, or bracket. Rear Mount Raise the vehicle on a hoist. Push up and pull down on the transm ission tailshaft while observing the transm ission m ount. If the rubber separates from the m etal plate of the m ount or if the tailshaft moves up but not down (m ount bottom ed out) replace th e m ount. If th ere is relative movement between a metal plate of the m ount and its attaching point, tighten the screws or nuts attaching the m ount to the transm ission or crossm em ber. 6A 5-9 INTAKE MANIFOLD Removal 1. D rain radiator and remove air cleaner. 2. Disconnect: • B attery negative cable at battery. • R adiator upper hose and heater hose at manifold. • W ater pum p by-pass at w ater pump. • A ccelerator linkage at carburetor. • Fuel line at carburetor. • Crankcase ventilation lines. • Spark advance hose at distributor. 3. Remove distributor cap and m ark rotor position with chalk, then remove distributor. 4. Rem ove (as req u ired ) air com pressor and b racket, accelerator return spring and bracket, and accelerator bellcrank. 5. Remove generator upper m ounting bracket. • W ith A /C , remove rear compressor bracket. 6. Remove manifold attaching bolts, then remove m ani­ fold and carburetor as an assembly. Discard gaskets and seals. 7. If manifold is to be replaced, transfer: • C arburetor and carburetor attaching bolts. • T em perature sending unit. • T herm ostat with housing (use new gasket). • H eater hose and w ater pump by-pass adapters. • TVS switch (if applicable). • Vacuum fitting(s). Front Mount Replacement 1. Rem ove m ount retain in g bolt from below fram e m ounting bracket. 2. R aise front of engine and rem ove m ount-to-engine bolts and remove m ount. R aise engine only enough for sufficient clearance. C heck for interference between re a r of engine and cowl panel w hich could cause distributor damage. 3. R eplace m ount to engine and lower engine into place. 4. Install retain in g bolt and to rq u e all bolts to specifications. Installation 1. Clean gasket and seal surfaces on manifold, block, and cylinder heads with degreaser. 2. Install gaskets on cylinder heads and new end seals on block. 3. Install manifold and torque bolts to specifications in the sequence outlined in fig. 6A5-8. 4. Install (if rem oved) air com pressor and b racket, accelerator bellcrank. Rear Mount Replacement 1. Support engine weight to relieve rear mounts. 2. Remove crossm em ber-to-m ount bolts. 3. On " P " Series with m anual transm ission and propeller shaft parking brake, remove m ount attaching bolts from fram e outrigger and clutch housing and remove rear m ounting cushions. 4. Rem ove m ount-to -tran sm issio n bolts, then rem ove mount. 5. On " P " Series with m anual transm ission and propeller shaft parking brake, install new mounting cushions and bolts. 6. Install new mount on transm ission. 7. W hile lowering transm ission, align and start crossm em ber-to-m ount bolts. 8. T orque bolts to specifications then bend lock tabs to bolt head as applicable. MARK IV V8 Fig. 6A5-8--lntake Manifold Torque Sequence LIGHT TRUCK SERVICE MANUAL 6A 5-10 MARK IV 5. Install distributor, positioning rotor at chalk m ark, then install distributor cap. 6. Connect: • Spark advance hose at distributor. • C rankcase ventilation lines. • Fuel line at carburetor. • A ccelerator linkage at carburetor. • W ater pump by-pass at w ater pump. • B attery negative cable at battery. 7. Install air cleaner. 8. Fill with coolant, sta rt engine, adjust ignition tim ing and carburetor idle speed and check for leaks. EXHAUST MANIFOLD Removal 1. Remove carburetor air cleaner and heat stove pipe. 2. Remove spark plugs. 3. D isconnect exh au st pipe from m anifold and hang exhaust pipe from fram e with wire. 4. Remove end bolts then remove center bolts and remove manifold. Fig. 6A5-10--A/C Compressor Mounting ROCKER ARM COVER Removal Installation If installing a new right side manifold, the carburetor heat stove m ust be transferred from the old unit (fig. 6A59). 1. Clean m ating surfaces on manifold and head, then install m anifold in position and install bolts. 2. Torque manifold bolts to specifications. 3. Connect exhaust pipe to manifold. 4. Install spark plugs and torque to 22 lb. ft. (30 N-m). 5. Install carburetor heat stove pipe. 6. S ta rt engine and check for leaks. 1. Remove air cleaner. 2. Disconnect crankcase ventilation hoses at rocker arm covers. 3. Disconnect electrical wiring harness from rocker arm clips. 4. Remove carburetor heat stove pipe from right exhaust manifold. 5. If the vehicle is equipped with air conditioning, remove the A /C compressor upper brace (fig. 6A5-10). 6. Remove rocker arm cover to head attaching bolts and remove rocker arm cover. NOTICE: If cover adheres to cylinder head, shear off by bum ping end of rocker arm cover with a rubber m allet. If cover will not come loose, C A REFU LLY pry until loose. DO N O T D IST O R T S E A L IN G FL A N G E . Installation STUD DUCT ASSEMBLY Fig. 6A5-9--Carburetor Heat Stove Assembly LIGHT TRUCK SERVICE MANUAL 1. Clean sealing surface on cylinder head and rocker arm cover with degreaser. Using a 3 /1 6 " (5m m ) bead of RTV, # 1052366 or equivalent, place rocker arm cover on the head, install retain in g bolts and torque to specification. Loose RTV sealant, or pieces causing installation interference, m ust be removed from both cylinder head and cover seal surfaces prior to applying new sealant. • W hen going around the attaching bolt holes, always flow the RTV on the inboard side of the holes. 2. On A /C equipped vehicles, install the A /C compressor upper brace. A djust pulley belt to specification. 3. Install carburetor heat stove pipe. 4. Connect electrical wiring harness at clips on rocker arm cover. 5. Connect crankcase ventilation hoses. 6. Install air cleaner, start engine and check for leaks. MARK IV VALVE MECHANISM Removal 1. Remove rocker arm covers as previously outlined. 2. Remove rocker arm nuts, rocker arm balls, rocker arm s and push rods. Place rocker arm s, rocker arm balls and push rods in a rack so they m ay be reinstalled in the sam e locations. Installation and Adjustment W henever new rocker arm s an d /o r rocker arm balls are being installed, coat bearing surfaces of rocker arm s and rocker arm balls with " M olykote" or its equivalent. 1. Install push rods. Be sure push rods seat in lifter socket. 2. Install rocker arm s, rocker arm balls and rocker arm nuts. T ig h ten rocker arm nuts until all lash is elim inated. 3. A djust valves when lifter is on base circle of cam shaft lobe as follows: a. C ran k engine until m ark on torsional dam per lines up with center or " O " m ark on the tim ing tab fastened to the crankcase front cover and the engine is in the # 1 firing position. This may be determ ined by placing fingers on the # 1 valve as the m ark on the dam per comes near the " O " m ark on the crankcase front cover. If the valves are not moving, the engine is in the # 1 firing position. If the valves move as the m ark comes up to the tim ing tab, the engine is in # 6 firing position and should be turned over one more tim e to reach the # 1 position. b. W ith the engine in the # 1 firing position as deter­ mined above, the following valves may be adjusted. - E x h a u s t- 1, 3 ,4 , 8 - I n t a k e - 1,2, 5, 7 6 A 5 -1 1 removed. This can be determ ined by rotating push rod while turning adjusting nut (fig. 6A 5-11). W hen play has been removed, turn adjusting nut in one full additional turn (to center lifter plunger), d. C rank the engine one revolution until the po in ter"o " m ark and torsional dam per m ark are again in alignm ent. T his is # 6 firing position. W ith the engine in this position the following valves may be adjusted. - Exhaust--2, 5 ,6 , 7 — In ta k e--3 ,4, 6, 8 4. Install rocker arm covers as previously outlined. 5. S tart engine and adjust carburetor idle speed. VALVE STEM OIL SEAL and/or VALVE SPRING Removal 1. Remove rocker arm cover as previously outlined. 2. Remove spark plug, rocker arm and push rod on the cylinder(s) to be serviced. 3. Install air line adapter Tool J-23590 to spark plug port and apply compressed air to hold the valves in place. 4. Using Tool J-5892 to compress the valve spring, remove the valve locks, valve cap and valve spring and dam per (fig. 6A5-12). 5. Remove the valve stem oil seal. Installation 1. Install new valve stem oil seal (coated with oil) in position over valve guide (fig. 6A5-13). Seal installa­ tion instructions are supplied with each service kit. Install seal following procedures outlined on the sup­ plied instruction sheet. c. Back out adjusting nut until lash is felt at the push rod th en tu rn in ad ju stin g n u t u ntil all lash is J-23590 Fig. 6 A 5 -1 1--Valve Adjustment Fig. 6A5-12--C om pressing Valve Spring LIGHT TRUCK SERVICE MANUAL 6A 5-12 MARK IV L ifte r B o d y Push Rod Seat M e te rin g V a lv e Fig. 6A5-13—Installing Valve Stem Oil Seal C h e c k B a ll C h e c k B a ll R e ta in e r 2. Set the valve spring and dam per and valve cap in place. 3. Com press the spring with Tool J-5892 and install the valve locks then release the compressor tool, making sure the locks seat properly in the groove of the valve stem. G rease m ay be used to hold the locks in place while releasing the compressor tool. 4. Install spark plug, and torque to 22 lb. ft. (30 N-m). 5. Install and ad ju st valve m echanism as previously outlined. Push Rod Seat R e ta in e r P lu n g e r C h e c k B a ll S p rin c P lu n g e r S p rin g Fig. 6A5-14--Hydraulic Valve Lifter VALVE LIFTERS H ydraulic valve lifters very seldom require attention. The lifters are extrem ely simple in design, readjustm ents are not necessary, and servicing of the lifters requires only that care and cleanliness be exercised in the handling of parts. Removal 1. Remove intake m anifold as previously outlined. 2. Remove valve m echanism as previously outlined. 3. Remove valve lifters. Place valve lifters in a rack so that they m ay be reinstalled in the sam e location. Installation 1. C oat foot of valve lifters w ith "M o ly k o te" or its equivalent and install valve lifters. M ake sure lifter foot is convex, 2. Install intake manifold as previously outlined. 3. Install and adjust valve m echanism as outlined. Disassembly 1. Hold the plunger down with a push rod, and using the blade of a small screw driver, remove the push rod seat retainer. 2. Remove the push rod seat and m etering valve (fig. 6A514). 3. Remove the plunger, ball check valve assembly and the plunger spring. 4. Remove the ball check valve and spring by prying the ball retainer loose from the plunger with the blade of a small screw driver (fig. 6A5-15). LIGHT TRUCK SERVICE MANUAL i Fig. 6A5-15--Removing Ball Check Valve Cleaning and Inspection Thoroughly clean all parts in cleaning solvent, and inspect them carefully. If any parts are dam aged or worn, the entire lifter assembly should be replaced. If the lifter body wall is scuffed or worn, inspect the cylinder block lifter bore. If the bottom of the lifter is scuffed or worn, inspect the cam shaft lobe. If the push rod seat is scuffed or worn, inspect the push rod. An additive containing EP lube, such as EOS, should always be added to crankcase oil for run-in when any new cam shaft or lifters are installed. All dam aged or worn lifters should be replaced. • For proper lifter rotation during engine operation, lifter foot m ust be convex. MARK IV 6A 5-13 5. Insert a 1/16" drift pin through both oil holes to hold the plunger down against the lifter spring tension (fig. 6A5-17). 6. Remove the 1/8" drift pin, refill assembly with SA E 10 oil. 7. Install the m etering valve and push rod seat (fig. 6A514). 8. Install the push rod seat retainer, press down on the push rod seat and remove the 1/16" drift pin from the oil holes. The lifter is now completely assembled, filled with oil and ready for installation. Before installing lifters, coat the bottom of the lifter with " M olykote" or its equivalent. CYLINDER HEAD ASSEMBLY Removal Fig. 6A5-16--lnstalling Ball Check Valve Assembly 1. Place the check ball on small hole in bottom of the plunger. 2. Insert check ball spring on seat in ball retainer and place retainer over ball so th a t spring rests on the ball. C arefully press the retainer into position in plunger with the blade of a small screw driver (fig. 6A5-16). 3. Place the plunger spring over the ball retainer and slide the lifter body over th e spring and plunger, being careful to line up the oil feed holes in the lifter body and plunger. 4. Fill the assembly with SA E 10 oil, then insert the end of a 1 /8 " drift pin into the plunger and press down solid. Do not attem pt to force or pum p the plunger. A t this point, oil holes in the lifter body and plunger assembly will be aligned (fig. 6A5-17). 1. Remove intake manifold as previously outlined. 2. Remove generator lower m ounting bolt and lay unit aside. 3. Remove exhaust manifolds as previously outlined. 4. If vehicle is equipped with A /C , remove A /C com pres­ sor and forward m ounting bracket. Lay unit aside. 5. Remove valve m echanism as previously outlined. 6. Drain cylinder block of coolant. 7. Remove cylinder head bolts, cylinder head and gasket. Place cylinder head on two blocks of wood to prevent dam age. Disassembly 1. W ith cylinder head removed, remove valve rocker arm nuts, balls and rocker arm s (if not previously done). 2. Using Tool J-8062, compress the valve springs (fig. 6A5-18) and remove valve keys. Release the com pres­ sor tool and remove rotators or spring caps, springs and spring dam per, then remove oil seals and valve spring shims. Vs" DRIFT PIN OIL FEED HOLE Fig. 6A5-17--Assem bling Hydraulic Lifter Fig. 6A5-18--C om pressing Valve Spring LIGHT TRUCK SERVICE MANUAL 6A 5-14 MARK IV 3. Remove valves from cylinder head and place them in a rack in their proper sequence so th at they can be assembled in their original positions. Cleaning 1. Clean all carbon from combustion cham bers and valve ports using Tool J-8089 (fig. 6A5-19). 2. Thoroughly clean the valve guides using Tool J-8101 (fig. 6A5-20). 3. Clean all carbon and sludge from push rods, rocker arm s and push rod guides. 4. Clean valve stems and heads on a buffing wheel. 5. C lean carbon deposits from head g asket m ating surface. NOTICE: Excessive valve stem to bore clearance will cause excessive oil consumption and may cause valve breakage. Insufficient clearance will result in noisy and sticky functioning of the valve and distu rb engine smoothness. 3. M easure valve stem clearance (fig. 6A5-21) as follows: a. Clam p a dial indicator on one side of the cylinder head rocker arm cover gasket rail. b. Locate the indicator so th at movement of the valve stem from side to side (crosswise to the head) will Inspection 1. Inspect the cylinder head for cracks in the exhaust ports, combustion cham bers, or external cracks to the coolant cham ber. 2. Inspect the valves for burned heads, cracked faces or dam aged stems. Fig. 6A5-21--Measuring Valve Stem Clearances Fig. 6A5-19--Cleaning Combustion Chambers J- 8101 Fig. 6A 5-20--C lean ing Valve Guides LIGHT TRUCK SERVICE MANUAL Fig. 6A 5-22--C hecking Valve Spring Tension MARK IV 6 A 5 -1 5 cause a direct movement of the indicator stem. The indicator stem m ust contact the side of the valve stem ju st above the valve guide. c. Drop the valve head about 1/16" (1.6m m ) off the valve seat. d. Move the stem of the valve from side to side using light pressu re to obtain a clearan ce reading. If clearance exceeds specifications, it will be necessary to ream valve guides for oversize valves as outlined. 4. Check valve spring tension with Tool J-8056 spring tester (fig. 6A5-22). Springs should be compressed to the specified height and checked against the specifica­ tions chart. Springs should be replaced if not within 10 lbs. (44 N ) of the specified load (w ithout dam pers). 5. Inspect rocker arm studs for wear of dam age. Inspect push rod guides for wear or dam age. Assembly Fig. 6A5-25--Measuring Valve Spring Installed Height 1. Insert a valve in the proper port. 2. A ssem ble the valve spring and related parts as follows: a. Install valve spring shim on valve spring seat then install a new valve stem oil seal over valve and valve guide. b. Set the valve spring (w ith dam per); and valve cap in place (fig. 6A5-23). c. Com press the spring with Tool J-8062. d. Install the valve locks and release the compressor tool, m aking sure th e locks seat properly in the groove of the valve stem. G rease may be used to hold the locks in place while releasing the compressor tool. 3. Install the rem aining valves. 4. Check the installed height of the valve springs, using a narrow thin scale. A cutaw ay scale will help (fig. 6A524). M easure from the top of the shim or the spring seat to the top of the valve spring or valve spring shield (fig. 6A5-25). If this is found to exceed the specified height, install a valve spring seat shim approxim ately 1/16" (1.6m m ) thick. A t no tim e should the spring be shimmed to give an installed height under the mini­ mum specified. Installation • The gasket surfaces on both the head and the block must be clean of any foreign m atter and free of nicks or heavy scratches. Cylinder bolt threads in the block and threads on the cylinder head bolts m ust be clean as dirt will affect bolt torque. 1. On engines using a ST E E L gasket, coat both sides of a new gasket with a good sealer. Spread the sealer thin and even. One method of applying the sealer th at will assure the proper coat is with the use of a paint roller. Too much sealer may hold the gasket away from the head or block. Fig. 6A5-23--Valve Spring Installation \ L G R IN D O U T THIS P O R T IO N T j T T T ] T | l | ' | l | T F j ' l ' | U lj TP | rTTj <1»| rr 1j n 7] 1 ' '2 3 r^ ry n y T T j 4 Fig. 6 A 5 -2 4 ~ C u ta w a y Scale 1 ! ' ] 1111 11' | 1 11 | 1111T 1' 5 6 Fig. 6 A 5 -2 6 --C ylin d e r Head Torque Sequence LIGHT TRUCK SERVICE MANUAL 6A 5-16 2. 3. 4. 5. 6. 7. 8. MARK IV • Use no sealer on engines using a composition ST EEL A SB E ST O S gasket. Place the gasket in position over the dowel pins with the bead up. Carefully guide the cylinder head into place over the dowel pins and gasket. C oat th read s of cylinder head bolts with sealing compound, # 1 0 5 2 0 8 0 or equivalent, and install bolts finger tight. Tighten each cylinder head bolt a little at a tim e in the sequence shown in figure 6A5-26 until the specified torque is reached. Install exhaust m anifolds as previously outlined. Install intake manifold as previously outlined. Install and a d ju st valve m echanism as previously outlined. ROCKER ARM STUDS Replacement The push rod guides are attached to the cylinder head by the rocker arm studs (fig. 6A 5-27). R eplace where necessary and torque rocker arm studs to specifications. VALVE GUIDE BORES head is im perative to insure th at the heat in the valve head will be properly carried away. Several different types of equipm ent are available for reseating valves seats. The recom m endations of the m anu­ facturer of the equipm ent being used should be carefully followed to attain proper results. Regardless of what type of equipm ent is used, however, it is essential th at valve guide bores be free from carbon or dirt to ensure proper centering of pilot in the guide. VALVES Valves th at are pitted can be refaced to the proper angle, insuring correct relation between the head and stem on a valve refacing m echanism. Valve stems which show excessive wear, or valves th at are w arped excessively should be replaced. W hen a valve head which is warped excessively is refaced, a knife edge will be ground on part or all of the valve head due to the am ount of m etal th at must be removed to completely reface. Knife edges lead to breakage, burning or pre-ignition due to heat localizing on this knife edge. If the edge of the valve head is less than 1/3 2 " (.80m m ) thick after grinding, replace the valve (fig. 6A 5-29). Several different types of equipm ent are available for refacing valves. The recom m endation of the m anufacturer of the equipm ent being used should be carefully followed to attain proper results. Valves with oversize stems are available (see specifica­ tions). To ream the valve guide bores for oversize valves use Tool Set J-7049. TORSIONAL DAMPER VALVE SEATS Removal R econditioning the valve seats is very im p ortant, because the seating of the valves must be perfect for the engine to deliver the power and perform ance built into it. A nother im portant factor is the cooling of the valve heads. Good contact between each valve and its seat in the 1. Remove fan belt, fan and pulley. 2. Remove the fan shroud assembly as outlined in Section 6B. • If additional operations (such as cam shaft removal) are not being perform ed, the radiator removal will not be necessary. 3. Remove accessory drive pulley then remove dam per retaining bolt. 4. Install Tool J-23523 on dam per then, turning puller screw, remove dam per. Fig. 6A5-27--R ocker Arm Stud & Push Rod G uide LIGHT TRUCK SERVICE MANUAL Fig. 6A 5-29--M easuring Valve Head MARK IV 6A 5-17 Installation NOTICE: The inertial weight section of the torsional dam per is assembled to the hub with a rubber type m aterial. The installation procedures (with proper tool) m ust be followed or movement of the inertia weight section on th e hub will destroy the tuning of the torsional dam per. 1. C oat front cover seal contact area (on dam per) with engine oil. 2. Place dam per in position over key on crankshaft. 3. Pull dam per onto crankshaft as follows: a. Install appropriate threaded end of Tool J-23523 into crankshaft. Install tool in crankshaft so th at at least 1 /2 " (6.5m m ) of th re a d engagem ent is obtained. 4. 5. 6. 7. 8. b. Install plate, thrust bearing and nut to complete tool installation. c. Pull dam per into position as shown in Figure 6A530. d. Remove tool from crankshaft then install dam per retaining bolt and torque to specifications. Install accessory drive pulley. Install fan shroud as outlined in Section 6B. Install fan and pulley to w ater pump hub and tighten securely. Install fan belt and adjust to specifications using strand tension gage. Fill cooling system, sta rt engine and check for leaks. CRANKCASE FRONT COVER Removal 1. Remove torsional dam per and w ater pum p as outlined. 2. Rem ove the two, oil p an -to -fro n t cover attach in g screws. 3. Remove the front cover-to-block attaching screws. 4. Pull the cover slightly forward only enough to perm it cutting of oil pan front seal. Fig. 6A5-31--Cutting Tabs on Oil Pan Front Seal 5. Using a sharp knife or other suitable cutting tool, cut oil pan front seal flush with cylinder block at both sides of cover (fig. 6A5-31). 6. Remove front cover and attaching portion of oil pan front seal. Remove front cover gasket. Installation 1. Clean gasket surface on block and crankcase front cover. 2. C ut tabs from the new oil pan front seal (fig. 6A5-32). Use a sharp instrum ent to ensure a clean cut. 3. Install seal to front cover, pressing tips into holes provided in cover. 4. Coat the gasket with gasket sealer and place in position on cover. 5. Apply a 1/8" (3m m ) bead of RTV sealer, # 1052366 or equivalent, to the joint formed at the oil pan and cylinder block (fig. 6A 5-33). 6. Position crankcase front cover over crankshaft. 7. Press cover downward against oil pan until cover is aligned and installed over dowel pins on block. Fig. 6A5-30--lnstalling Torsional Dam per LIGHT TRUCK S E R V I^ MANUAL 6A 5-18 MARK IV Fig. 6A5-33--Applying Front Cover Sealer 8. Install and partially tighten the two, oil pan-to-front cover attaching screws. 9. Install the front cover-to-block attaching screws. 10. Torque all screws to specifications. 11. Install torsional dam per and w ater pump as previously outlined. Fig. 6A5-34--lnstalling Oil Seal OIL SEAL (FRONT COVER) Replacement With Cover Removed 1. W ith cover removed, pry oil seal out of cover from the front with a large screw driver. 2. Install new seal so th a t open end of the seal is toward the inside of cover and drive it into position with Tool J-22102. Support rear of cover at seal area. With Cover Installed 1. W ith torsional dam per removed, pry seal out of cover from the front with a large screw driver. Be careful not to dam age the surface on the crankshaft. 2. Install new seal so th a t open end of seal is toward the inside of cover and drive it into position with Tool J-22102. (fig. 6A 5-34). CAMSHAFT Measuring Lobe Lift 1. Remove the valve m echanism as previously outlined. 2. Position in d icato r w ith ball socket a d a p te r (Tool J-8520) on push rod (fig. 6A5-35). M ake sure push rod is in the lifter socket. 3. R otate the crankshaft slowly in the direction of rotation until the lifter is on the heel of the cam lobe. At this point, the push rod will be in its lowest position. 4. Set dial indicator on zero, then rotate the crankshaft slowly, or a tta c h an au x iliary sta rte r sw itch and "bum p" the engine over, until the push rod is fully raised position. • W henever the engine is cranked remotely at the starter, with a special jum per cable or other means, Fig. 6A5-35--Measuring Camshaft Lobe Lift the distributor prim ary lead should be disconnected from the distributor (coil). 5. C om pare the total lift recorded from the dial indicator with specifications. 6. If cam shaft readings for all lobes are within specifica­ tions, remove dial indicator assembly. 7. Install and adjust valve m echanism as outlined. Removal 1. 2. 3. 4. Remove valve lifters as previously outlined. Remove crankcase front cover as previously outlined. Remove grille. Remove fuel pum p push rod as outlined in Section 6C. MARK IV 6A 5-19 W henever a new cam shaft is installed, replacem ent of all valve lifters oil filter and engine oil is recommended to insure durability of the cam shaft lobes and lifter feet. 1. Lubricate cam shaft journals with engine oil and install cam shaft. 2. Install tim ing chain on cam shaft sprocket. Hold the sprocket vertically with the chain hanging down and align m arks on cam shaft and crankshaft sprockets. (Refer to fig. 6A5-37). 3. Align dowel in cam shaft with dowel hole in cam shaft sprocket then install sprocket on cam shaft. 4. Draw the cam shaft sprocket onto cam shaft using the mounting bolts. Torque to specifications. 5. Lubricate tim ing chain with engine oil. 6. Install fuel pump push rod as outlined in Section 6C. 7. Install grille. 8. Install crankcase front cover as previously outlined. Fig. 6A5-36--Removing Camshaft 5. Complete cam shaft removal as follows: • Sprocket is a light fit on cam shaft. If sprocket does not come off easily a light blow on the lower edge of the sprocket (with a plastic m allet) should dislodge the sprocket. 6. Install two 5 /1 6 " - 1 8 x 4 " bolts in cam shaft bolt holes then remove cam shaft (fig. 6A5-36). NOTICE: All cam shaft journals are the same diam eter and care must be used in removing cam shaft to avoid dam age to bearings. Inspection The cam shaft bearing journals should be m easured with a m icrom eter for an out-of-round condition. If the journals exceed .001" out-of-round, the cam shaft should be replaced. Installation W henever a new cam shaft is installed coat cam shaft lobes with "M olykote" or its equivalent. 9. Install valve lifters as previously outlined. CAMSHAFT BEARINGS Removal C am shaft bearings can be replaced while engine is disassembled for overhaul or w ithout complete disassembly of the engine. To replace bearings without complete disas­ sembly remove the cam shaft and crankshaft leaving cylin­ der heads attached and pistons in place. Before removing crankshaft, tape threads of connecting rod bolts to prevent dam age to crankshaft. Fasten connecting rods against sides of engine so they will not be in the way while replacing cam shaft bearings. 1. W ith cam shaft and crankshaft removed, drive cam ­ shaft rear plug from cylinder block. 2. Using Tool J-6098 with nut and thrust washer installed to end of threads, index pilot in cam shaft front bearing and install puller screw through pilot. 3. Install remover and installer tool with shoulder toward bearing, making sure a sufficient am ount of threads are engaged. #6 C Y LIN D ER AT T.D.C. Fig. 6A 5-37--Tim ing Sprocket Alignment M arks Fig. 6A5-38--R em oving Cam shaft Bearings LIGHT TRUCK SERVICE MANUAL 6A 5-20 MARK IV 4. Using two wrenches, hold puller screw while turning nut. W hen bearing has been pulled from bore, remove remover and installer tool and bearing from puller screw (fig. 6A 5-38). 5. Remove rem aining bearings (except front and rear) in the same m anner. It will be necessary to index pilot in cam shaft rear bearing to remove the rear interm ediate bearing. 6. Assemble remover and installer tool on driver handle and rem ove c a m sh a ft front and re a r bearings by driving towards center of cylinder block (fig. 6A5-39). Installation T he cam sh aft fro n t and re a r bearings should be installed first. These bearings will act as guides for the pilot and center the rem aining bearings being pulled into place. 1. Assemble remover and installer tool on driver handle and install cam shaft front and rear bearings by driving towards center of cylinder block (fig. 6A5-39). 2. Using Tool Set J-6098 with nut then thrust washer installed to end of threads, index pilot in cam shaft front bearing and install puller screw through pilot. 3. Index cam shaft bearing in bore (with oil hole aligned as outlined below), then install remover and installer tool on puller screw with shoulder toward bearing. • N um ber one through num ber four cam bearing oil hole m ust be aligned with oil holes in cam bearing bore. • The num ber five bearing bore is annulus, and cam bearing m ust be positioned at or near the 6 o’clock position. 4. Using two wrenches, hold puller screw while turning nut. A fter bearing has been pulled into bore, remove the remover and installer tool from puller screw, and check alignm ent of oil hole in cam shaft bearing. 5. Install rem aining bearings in the same m anner. It will be necessary to index pilot in the cam shaft rear bearing to install the rear interm ediate bearing. 6. C oat new rear plug O.D. with # 1052080 sealant, or equivalent, and install flush to 1/32" (.80m m ) deep. OIL PAN Removal 1. 2. 3. 4. 5. Disconnect battery negative cable. Loosen fan shroud. Remove air cleaner. Remove distributor cap. Raise vehicle and drain oil pan. • If equipped with m anual transm ission, rem ove starter. 6. Rem ove torque converter cover or clutch cover as applicable. 7. Remove oil filter. 8. On gage equipped vehicles, remove oil pressure line from side of block. NOTICE: Rem oval of pressure line is im p o rtan t to prevent crushing of line when raising engine. 9. Remove m ount "th ro u g h " bolts and raise engine. 10. Remove oil pan bolts and drop pan. Installation If installing new oil pan, transfer dipstick tube from old unit. 1. W ith clean sealing surfaces on pan and block, place oil pan on block and install oil pan bolts. Torque to 135 lb. in. (15N-m ). 2. Lower engine on mounts and install m ount through bolts. Torque to 75 lb. ft. (100 N-m). 3. Install oil pressure line, if applicable, and install oil filter. 4. Install torque converter cover or clutch cover, as applicable. • If equipped with m anual transm ission, install starter. 5. Lower vehicle. 6. Install distributor cap and tighten fan shroud. 7. Fill crankcase with oil; see owners m anual. 8. Install air cleaner and connect battery negative cable. 9. S ta rt engine and check for leaks. OIL PUMP Removal 1. Remove oil pan as previously outlined. 2. Rem ove pum p to rea r m ain bearing cap bolt and remove pump and extension shaft. Disassembly (Figure 6A5-40) 1. Rem ove the pum p cover a ttac h in g screws and the pum p cover. Fig. 6A5-39--Replacing Camshaft Front Bearing LIGHT TRUCK SERVICE MANUAL 2. M ark gear teeth so they m ay be reassem bled with the same teeth indexing. Remove the idler gear and the drive gear and shaft from the pum p body. 3. Rem ove the pressure reg u lato r valve retain in g pin, pressure regulator valve and related parts. MARK IV 6A5-21 3. Install oil pan previously outlined. CONNECTING ROD BEARINGS Connecting rod bearings are of the precision insert type and do not utilize shims for adjustm ent. DO N O T FILE R O D S O R R O D CA PS. If clearances are found to be excessive a new bearing will be required. Service bearings are available in standard size and .001" and .002" under­ size for use with new and used standard size crankshafts, and in .010" and .020" undersize for use with reconditioned crankshafts. Inspection and Replacement 2 1. 2. 3. 4. 5. 6. 7. S h a ft Extension S h a ft C ouplin g Pump Body Drive Gear and S haft Id le r Gear P ickup Screen and Pipe Pump Cover 8. 9. 10. 11. 12. Pressure R e gulator Valve Pressure R egulator S p rin g W a sh e r R etaining Pin S crew s Fig. 6A5-4C)--Oil Pump 4. If the pickup screen and pipe assem bly need replacing, the entire pump m ust be replaced. The screen and pipe assembly is welded to the pum p body. Cleaning and Inspection 1. W ash all parts in cleaning solvent and dry with compressed air. 2. Inspect the pump body and cover for cracks or exces­ sive wear. 3. Inspect pump gears for dam age or excessive wear. • The pum p gears and body are not serviced sepa­ rately. If the pump gears or body are dam aged or worn, replacem ent of the entire oil pum p assembly is necessary. 4. Check the drive gear shaft for looseness in the pum p body. 5. Inspect inside of pum p cover for w ear th a t would perm it oil to leak past the ends of the gears. 6. Inspect the pickup screen and pipe assem bly for dam age to screen, pipe or relief grom m et. 7. Check the pressure regulator valve for fit. 1. W ith oil pan and oil pum p rem oved, rem ove the connecting rod cap and bearing. Before removal of connecting rod cap, m ark the side of the rod and cap with the cylinder num ber to assure m atched reassem ­ bly of rod and cap. 2. Inspect the bearing for evidence of wear or dam age. (Bearings showing the above should not be installed.) 3. W ipe both upper and lower bearing shells and crankpin clean of oil. 4. M easure the crankpin for out-of-round or taper with a m icrom eter. If not w ithin specifications replace or recondition the crankshaft. If within specifications and a new bearing is to be installed, m easure the m axim um diam eter of the crankpin to determ ine new bearing size required. 5. If within specifications m easure new or used bearing clearances with Plastigage or its equivalent. If a bearing is being fitted to an out-of-round crankpin, be sure to fit to the m axim um diam eter of the crankpin. If the bearing is fitted to the minimum diam eter and the crankpin is out-of-round .001" in terference between the bearing and crankpin will result in rapid bearing failure. Assembly (Figures 6A5-40) 1. Install the pressure regulator valve and related parts. 2. Install the drive gear and shaft in the pum p body. 3. Install the idler gear in the pum p body with the smooth side of gear towards pum p cover opening. 4. Install gasket and the pum p cover and torque attaching screws to specifications. 5. T urn drive shaft by hand to check for smooth operation. Installation 1. A ssem ble pum p and extension sh aft to rear m ain bearing cap, aligning slot on top end of extension shaft with drive tang on lower end of distributor drive shaft. 2. Install pum p to rear bearing cap bolt and torque to specifications. Fig. 6A5-41--Gaging Plastic On Crankpin LIGHT TRUCK SERVICE MANUAL 6A 5-22 MARK IV a. Place a piece of gaging plastic, the length of the bearing (parallel to the crankshaft), on the crankpin or bearing surface (fig. 6A 5-41). Plastic gage should be positioned in the middle of upper or lower bearing shell. (B earings are eccentric and false readings could occur if placed elsewhere). b. Install the bearing in the connecting rod and cap. c. Install the bearing cap and evenly torque nuts to specifications. Do not turn the crankshaft with the gaging plastic installed. d. Remove the bearing cap and using the scale on the gaging plastic envelope, m easure the gaging plastic width at the widest point (fig.6A5-42). 6. If the clearance exceeds specifications, select a new, correct size, bearing and rem easure the clearance. Be sure to check w hat size bearing is being removed in order to determ ine proper replacem ent size bearing. If clearance cannot be brought to within specifications, the crankpin will have to be ground undersize. If the crankpin is already at m axim um undersize, replace crankshaft. 7. C oat the bearing surface with oil, install the rod cap and torque nuts to specifications. 8. W hen all connecting rod bearings have been installed tap each rod lightly (parallel to the crankpin) to make sure they have clearance. 9. M easure all connecting rod side clearances (see speci­ fications) between connecting rod caps (fig. 6A5-43). Fig. 6A5-43--Measuring Connecting Rod Side Clearance Selective fitting of both rod and main bearing inserts is necessary in production in order to obtain close tolerances. For this reason you may find one half of a standard insert with one half of a .001" undersize insert which will decrease the clearance .0005 " from using a full standard bearing. MAIN BEARINGS Inspection M ain bearings are of the precision insert type and do not utilize shims for adjustm ent. If clearances are found to be excessive, a new bearing, both upper and lower halves, will be required. Service bearings are available in standard size and .0 0 1 ", .0 0 2 ", .0 0 9 ", .010" and .020" undersize. In general, the lower half of the bearing (except # 1 bearing) shows a greater wear and the most distress from fatigue. If upon inspection the lower half is suitable for use, it can be assum ed th a t the upper half is also satisfactory. If the lower half shows evidence of w ear or dam age, both upper and lower halves should be replaced. Never replace one half w ithout replacing the other half. Checking Clearance To obtain the most accurate results with "P lastig ag e", (or its equivalent) a wax-like plastic m aterial which will compress evenly between the bearing and journal surfaces w ithout dam aging either surface, certain precautions should be observed. If the engine is out of the vehicle and upside down, the crankshaft will rest on the upper bearings and the total clearance can be m easured between the lower bearing and jo u rn al. If the engine is to rem ain in th e vehicle, the cran k sh a ft m ust be supported upw ard to rem ove the clearance from the upper bearing. The total clearance can then be m easured between the lower bearing and journal. To assure the proper seating of the crankshaft, all bearing cap bolts should be at their specified torque. In addition, preparatory to checking fit of bearings, the surface of the crankshaft journal and bearing should be wiped clean of oil. Fig. 6 A 5 -4 2 -M e a s u rin g G agin g Plastic LIGHT TRUCK SERVICE MANUAL 1. W ith the oil pan and oil pum p removed, and starting with the rear main bearing, remove bearing cap and wipe oil from journal and bearing cap. MARK IV 6A 5-23 5. On the edge of gaging plastic envelope th ere is a graduated scale which is correlated in thousandths of an inch. W ithout removing the gaging plastic, measure its compressed width (at the widest point) with the graduations on the gaging plastic envelope (fig. 6A545). N orm ally main bearing journals wear evenly and are not out-of-round. However, if a bearing is being fitted to an out-of-round (.001" m ax.), be sure to fit to the m axim um diam eter of the journal: If the bearing is fitted to the m inim um diam eter and the journal is outof-round .001", interference between the bearing and jo u rn a l will result in rapid bearing failure. If the flattened gaging plastic tapers toward the middle or ends, there is a difference in clearance indicating taper, low spot or other irregularity of the bearing or journal. Be sure to m easure the journal with a m icrom eter if the flattened gaging plastic indicates m ore th a n .001" difference. Fig. 6A5-44--Gaging Plastic on Journal 2. Place a piece of gaging plastic the full width of the bearing (parallel to the crankshaft) on the journal (fig. 6A5-44). Do not rotate the crankshaft while the gaging plastic is between the bearing and journal. 3. Install the bearing cap and evenly torque the retaining bolts to specifications. Bearing cap M U ST be torqued to specifications in order to assure proper reading. V ariatio n s in torque affect th e com pression of the plastic gage. 4. Remove bearing cap. The flattened gaging plastic will be found adhering to either the bearing shell or journal. Fig. 6A 5-45--M easuring G agin g Plastic 6. If the bearing clearance is within specifications, the bearing insert is satisfactory. If the clearance is not within specifications, replace the insert. Always replace both upper and lower inserts as a unit. If a new bearing cap is being installed and clearance is less than .001", inspect for burrs or nicks; if none are found then install shims as required. 7. A standard, .001" or .002" undersize bearing may produce the proper clearance. If not, it will be neces­ sary to regrind the crankshaft journal for use with the next undersize bearing. A fter selecting new bearing, recheck clearance. 8. Proceed to the next bearing. A fter all bearings have been checked rotate the crankshaft to see th a t there is no excessive drag. W hen checking # 1 main bearing, loosen accessory drive belts so as to prevent tapered reading with plastic gage. Fig. 6A 5-46--M easuring Crankshaft End Play LIGHT TRUCK SERVICE MANUAL 6A 5-24 MARK IV 9. M easure crankshaft end play (see specifications) by forcing the crankshaft to the extrem e front position. M easure at the front end of the rear m ain bearing with a feeler gage (fig. 6A 5-46). 10. Install a new rear m ain bearing oil seal in the cylinder block and m ain bearing cap. .004 SHIM STOCK Replacement M ain bearings m ay be replaced w ith or w ithout removing the crankshaft. 11/64 With Crankshaft Removal 1. Remove and inspect the crankshaft. 2. Remove the m ain bearings from the cylinder block and main bearing caps. 3. C oat bearing su rfaces of new, correct size, m ain bearings with oil and install in the cylinder block and main bearing caps. 4. Install the crankshaft. Fig. 6A5-47--Oil Seal Installation Tool Without Crankshaft Removal 1. W ith oil pan, oil pum p and spark plugs rem oved, remove cap on m ain bearing requiring replacem ent and remove bearing from cap. 2. Install a m ain bearing removing and installing tool in oil hole in crankshaft journal. If such a tool is not availale, a cotter pin m ay be bent as required to do the job. 3. R otate the crankshaft clockwise as viewed from the front of engine. This will roll upper bearing out of block. 4. Oil new selected size upper bearing and insert plain (unnotched) end between crankshaft and indented or notched side of block. R otate the bearing into place and remove tool from oil hole in crankshaft journal. 5. Oil new lower bearing and install in bearing cap. 6. Install m ain bearing cap with arrows pointing toward front of engine. 7. Torque all m ain bearing caps E X C E P T T H E R E A R M A IN C A P to specifications. Torque rear m ain bear­ ing cap to 10-12 lb. ft. (14-16N -m ) then tap end of crankshaft, first rearw ard then forward with a lead ham m er. T his will line up re a r m ain bearing and crankshaft th ru st surfaces. R etorque all m ain bearing caps to specifications. Fig. 6A5-48--Removing Oil Seal - Lower Half OIL SEAL (REAR MAIN) Replacement • Always replace the upper and lower seal as a unit. The rear m ain bearing oil seal can be replaced (both halves) without removal of the crankshaft. E xtrem e care should be exercised when installing this seal to protect the sealing bead located in the channel on the outside diam eter of the seal. An installation tool (fig. 6A5-47) can be used to protect the seal bead when positioning seal as follows: 1. W ith the oil pan and oil pum p removed, remove the rear m ain bearing cap. 2. Remove oil seal from the bearing cap by prying from the bottom with a sm all screw driver (fig. 6A5-48). LIGHT TRUCK SERVICE MANUAL Fig. 6A5-49--Removing Oil Seal - Upper Half 3. To remove the upper half of the seal, use a small ham m er to tap a brass pin punch on one end of seal until it protrudes far enough to be removed with pliers (fig. 6A5-49). 4. Clean all sealant and foreign m aterial from cylinder case bearing cap and crankshaft, using a non-abrasive cleaner. 5. Inspect com ponents for nicks, scratches, burrs and m achining defects at all sealing surfaces, case assembly and crankshaft. 6. C oat seal lips and seal bead with light engine oil - keep oil off seal m ating ends. MARK IV 7. Position tip of tool between crankshaft and seal seat in cylinder case. 8. Position seal between crankshaft and tip of tool so that seal bead contacts tip of tool. M ake sure th at oil-seal lip is positioned toward front of engine (fig. 6A5-50). 9. Roll seal around crankshaft using tool as a "shoe­ horn" to protect seal bead from sharp corner of seal seat surface in cylinder case. Installation tool must rem ain in position until seal is properly positioned with both ends flush with block. 10. Remove tool, being careful not to w ithdraw seal. 11. Install seal half in bearing cap, again using tool as a "shoe-horn", feeding seal into cap using light pressure with thum b and finger. 12. Install bearing cap to case with sealant applied to the cap-to-case interface being careful to keep sealant off the seal split line (fig. 6A 5 -5 1). 13. Install the rear m ain bearing cap (with new seal) and torque to 10-12 lb. ft. (14-16N -m ). T ap end of crank­ shaft first rearw ard then forw ard with lead ham m er. This will line up thru st surfaces. R etorque bearing cap to specifications. DU ST SEAL 6A 5-25 CONNECTING ROD AND PISTON ASSEMBLIES Removal 1. Remove oil pan, oil pum p and cylinder head as pre­ viously outlined. 2. For the cylinder being serviced, turn crankshaft until piston is at the bottom of the stroke. Place a cloth on top of the piston. 3. Use a ridge ream er to remove any ridge an d /o r deposits from the upper end of the cylinder bore. 4. Turn crankshaft until piston is at top of stroke and remove cloth and cuttings. 5. Remove connecting rod cap and install Tool J-5329 (3/ 8 " ) on studs. Push connecting rod and piston assembly out of top of cylinder block. It will be necessary to turn the c ra n k sh aft slightly to disconnect some of the connecting rod and piston assemblies and push them out of the cylinder. Disassembly 1. Remove connecting rod bearings from connecting rods and caps. If bearings are being reused, place them in a rack so they may be reinstalled in their original rod and cap. 2. Remove piston rings by expanding and sliding them off the pistons. 3. Place connecting rod and piston assem bly on Tool J-24086-20. U sing an arb o r press and piston pin remover, J-24086-8, press the piston pin out of connect­ ing rod and piston (fig. 6A5-52). PRESS -PISTON PIN REMOVER J-24086-8 Fig. 6A5-50--Crankshaft Oil Seal - Rear Main APPLY SEALANT TO SHADED AREAS ONLY FIXTURE & SUPPORT ASSEMBLY J-24086-20 Fig. 6 A 5 -5 1 -S e a lin g Bearing C ap Fig. 6A5-52--R em oving Piston Pin LIGHT TRUCK SERVICE MANUAL 6A 5-26 MARK IV Cleaning and Inspection Connecting Rods PRESS W ash connecting rods in cleaning solvent and dry with compressed air. Check for twisted or bent rods and inspect for nicks or cracks. R eplace connecting rods th a t are dam aged. Pistons C lean varnish from piston skirts and pins w ith a cleaning solvent. DO N O T W IR E B R U SH A N Y PA R T O F T H E PIST O N . Clean the ring grooves with a groove cleaner and m ake sure oil ring holes and slots are clean. Inspect the piston for cracked ring lands, skirts or pin bosses, wavy or worn ring lands, scuffed or dam aged skirts, eroded areas at top of the piston. Replace pistons th at are dam aged or show signs of excessive wear. Inspect the grooves for nicks or burrs th at m ight cause the rings to hang up. M easure piston skirt (across center line of piston pin) and check clearance. PISTON PIN— ^ INSTALLER J-24086-9 PISTON PIN Piston Pins T he piston pin c learan ce is designed to m aintain adequate clearance under all engine operating conditions. Because of this, the piston and piston pin are a m atched set and not serviced separately. Inspect piston pin bores and piston pins for wear. Piston pin bores and piston pins m ust be free of varnish or scuffing when being m easured. The piston pin should be m easured with a m icrom eter and the piston pin bore should be measured with a dial bore gage or an inside m icrom eter. If clearance is in excess of the .001" wear limit, the piston and piston pin assembly should be replaced. Fig. 6A5-53--lnstalling Piston Pin Assembly 1. L ubricate piston pin holes in piston and connecting rod to facilitate installation of pin. 2. Place connecting rod in piston and hold in place with piston pin guide and piston pin. Place assembly on fixture and support assembly. 3. Using piston pin installer, J-24086-9, press the piston pin into the piston and connecting rod (fig. 6A5-53). NOTICE: A fter installer hub bottom s on support assem ­ bly, do not exceed 5000 psi pressure, as this could cause structural dam age to the tool. 4. Remove piston and connecting rod assembly from tool and check piston for freedom of movement on piston pin. Piston Rings All compression rings are m arked on the upper side of the ring. W hen installing compression rings, make sure the m arked side is tow ard the top of the piston. The top ring is chrome faced, or treated with molybdenum for m aximum life. The oil control rings are of three piece type, consisting of two segments (rails) and a spacer. 1. Select rings com parable in size to the piston being used. LIGHT TRUCK SERVICE MANUAL Fig. 6A5-54--Measuring Ring Gap 2. Slip the compression ring in the cylinder bore; then press the ring down into the cylinder bore about 1/4" (6.5m m ) (above ring travel). Be sure ring is square with cylinder wall. 3. M easure the space or gap between the ends of the ring with a feeler gage (fig. 6A 5-54). MARK IV Fig. 6A5-55--Checking Ring in Groove 6A 5-27 the ring entirely around the groove (fig. 6A5-55) to make sure th at the ring is free. If binding occurs at any point, the cause should be determ ined. If binding is caused by ring groove, correct by dressing with a fine cut file. If the binding is caused by a distorted ring, check a new ring. 8. Install piston rings as follows (fig. 6A5-56): a. Install oil ring spacer in groove. b. Hold spacer ends butted and install lower steel oil ring rail with gap properly located. c. Install upper steel oil ring rail with gap properly located. d. Flex the oil ring assembly to make sure ring is free. If binding occurs at any point the cause should be determ ined. If binding is caused by ring groove, correct by dressing groove with a fine cut file. If binding is caused by a distorted ring, check a new ring. e. Install second compression ring expander then ring with gaps properly located. f. Install top com pression ring with gap properly located. 9. Proper clearance of the piston ring in its piston ring groove is very im portant to provide proper ring action and reduce wear. Therefore, when fitting new rings, the clearances between the surfaces of the ring and groove should be m easured (fig. 6A5-57). (See Specifications). Installation C ylinder bores m ust be clean before piston installation. This may be accomplished with a hot water and detergent wash or with a light honing as necessary. A fter cleaning, the bores should be swabbed several times with light engine oil and a clean dry cloth. 1. Lubricate connecting rod bearings and install in rods and rod caps. Fig. 6A5-56--Ring Gap Location 4. If th e gap betw een the ends of th e ring is below specifications, remove the ring and try another for fit. 5. Fit each compression ring to the cylinder in which it is going to be used. 6. If the pistons have not been cleaned and inspected as previously outlined, do so. 7. Slip the outer surface of the top and second com pres­ sion ring into the respective piston ring groove and roll Fig. 6A5-57--Measuring Ring Groove Clearance LIGHT TRUCK SERVICE MANUAL 6A 5-28 MARK IV 2. Lightly coat pistons, rings and cylinder walls with light engine oil. 3. W ith bearing caps removed, install Tool J-5329 (3 /8 " ) on connecting rod bolts. 4. Install each connecting rod and piston assembly in its respective bore. Install with connecting rod bearing tang slots on side opposite cam shaft. Use Tool J-8037 to compress the rings. G uide the connecting rod into place on the crankshaft journal with Tool J-6305 (11/ 3 2 "). Use a ham m er handle and light blows to install the piston into the bore. Hold the ring compressor firmly against the cylinder block until all piston rings have entered the cylinder bore. 5. Remove Tool J-5329. 6. Install the b earin g caps and to rq u e nuts to specifications. Be sure to install new pistons in the cylinders for which they were fitted, and used pistons in the cylinder from which they were removed. Each connecting rod and bearing cap should be m arked, beginning at the front of the engine. Cylinders 1,3,5 and 7 in the left bank and, 2 4, 6 and 8 in the right bank. The num bers on the connecting rod and bearing cap must be on the sam e side when installed in the cylinder bore. If a connecting rod is ever transposed from one block or cylinder to another, new bearings should be fitted and the connecting rod should be num bered to correspond with the new cylinder num ber. CYLINDER BLOCK Cleaning and Inspection 1. W ash cylinder block thoroughly in cleaning solvent and clean all gasket surfaces. 2. Remove oil gallery plugs and clean all oil passages. 3. Clean and inspect w ater passages in the cylinder block. 4. Inspect the cylinder block for cracks in the cylinder walls, w ater jacket, valve lifter bores and main bearing webs. 5. M easure the cylinder walls for taper, out-of-round or excessive ridge at top of ring travel. This should be done with a dial indicator. Set the gage so th a t the thrust pin must be forced in about 1/4" (6.5m m ) to enter gage in cylinder bore. C enter gage in cylinder and turn dial to " 0 " . C arefully work gage up and down cylinder to determ ine taper and turn it to different points around cylinder wall to determ ine the out-of-round condition. If cylinders were found to exceed specifications, honing or boring will be necessary. Conditioning The perform ance of the following operation is contin­ gent upon engine condition a t tim e of repair. If the cylinder block inspection indicated th at the block was suitable for continued use except for out-of-round or tapered cylinders, they can be conditioned by honing or boring. If the cylinders were found to have less than .005" taper or wear, they can be conditioned with a hone and fitted with the high limit standard size piston. A cylinder bore of less then .005 " wear or taper m ay not entirely clean up when fitted to a high limit piston. If it is desired to entirely clean up the bore in these cases, it will be necessary to rebore for LIGHT TRUCK SERVICE MANUAL an oversize piston. If more than .005" taper or wear, they should be bored and honed to the sm allest oversize that will perm it complete resurfacing of all cylinders. W hen pistons are being fitted and honing is not necessary, cylinder bores may be cleaned with a hot w ater and deterg en t wash. A fter cleaning, the cylinder bores should be swabbed several times with light engine oil and a clean cloth and then wiped with a clean dry cloth. Boring 1. Before using any type boring b ar, the top of the cylinder block should be filed off to remove any dirt or burrs. This is very im portant. If not checked, the boring bar may be tilted which would result in the rebored cylinder wall not being a t rig h t angles to the crankshaft. 2. The piston to be fitted should be m easured with a microm eter, m easuring at the center of the piston skirt and at right angles to the piston pin. The cylinder should be bored to the same diam eter as the piston and honed to give the specified clearance. 3. The instructions furnished by the m anufacturer of the equipm ent being used should be carefully followed. Honing 1. W hen cylinders are to be honed, follow the hone m anufacturer’s recom m endations for the use of the hone and cleaning and lubrication during honing. 2. Occasionally during the honing operation, the cylinder bore should be thoroughly cleaned and the piston selected for the individual cylinder checked for correct fit. 3. W hen finish honing a cylinder bore to fit a piston, the hone should be moved up and down at a sufficient speed to obtain very fine uniform surface finish marks, in a cross-hatch pattern of approxim ately 45° to 65° in­ cluded angle. The finish m arks should be clean but not sharp, free from imbedded particles and torn or folded metal. 4. Perm anently m ark the piston for the cylinder to which it has been fitted and proceed to hone cylinders and fit the rem aining pistons. NOTICE: H andle th e pistons w ith care and do not attem pt to force them through the cylinder until the cylinder has been honed to correct size as this type piston can be distorted through careless handling. 5. Thoroughly clean the bores with hot w ater and deter­ gent. Scrub well with a stiff bristle brush and rinse thoroughly with hot w ater. It is extrem ely essential that a good cleaning operation be perform ed. If any of the abrasive m aterial is allowed to rem ain in the cylinder bores, it will rapidly wear the new rings and cylinder bores in addition to the bearings lubricated by the contam inated oil, the bores should be swabbed and then wiped with a clean dry cloth. C ylinder should not be cleaned with kerosene or gasoline. Clean the rem ainder of the cylinder block to remove the excess m aterial spread during the honing operation. Piston Selection 1. C heck U SE D piston to cylinder bore clearance as follows: MARK IV a. M easure th e "C y lin d er Bore D ia m e ter" w ith a telescope gage |2 - 1/2" (64m m ) from top of cylinder bore|. b. M easu re th e "P isto n D ia m e te r" (a t skirt across center line of piston pin). c. S u b tract piston diam eter from cylinder bore diam e­ ter to determ ine " Piston to Bore C learance ". d. Locate piston to bore clearance on Piston Selection C h art and determ ine if piston to bore clearance is in the acceptable range. 2. If used piston is not acceptable,-determ ine if a new piston can fit cylinder bore. 3. If cylinder bore m ust be reconditioned, m easure new piston diam eter (across center line of piston pin) then hone cylinder bore to correct clearance. 4. M ark the piston to identify the cylinder for which it was fitted. OIL FILTER BYPASS VALVE Inspection and Replacement W ith the oil filter removed, check the spring and fibre valve for operation. Inspect for a cracked or broken valve. If replacem ent is necessary, the oil filter adapter and bypass valve assembly must be replaced as an assembly. Clean valve cham ber in cylinder block thoroughly. Torque retain­ ing screws to specifications. ENGINE ASSEMBLY Removal 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. Remove hood. Disconnect battery cables at battery. Remove air cleaner. D rain radiator and block. D isconnect ra d ia to r and h eater hoses and remove radiator and fan shroud. Disconnect wires at: • S ta rte r Solenoid • G enerator • T R C Speed Switch • T R C Solenoid • T em perature switch • Oil Pressure Switch • D istributor Disconnect: • A ccelerator linkage a t inlet manifold. • Fuel line, from tank, at fuel pump. • Hoses at fuel vapor storage canister (if applicable). • Vacuum line to power brake unit a t manifold, if so equipped. Remove power steering pump and A /C compressor and lay aside, if so equipped. Raise vehicle on hoist. D rain crankcase. D isconnect exhaust pipe at m anifold and, if so equipped, converter b rack et a t transm ission rear m ount. Remove starter. 6A 5-29 13. Remove flywheel splash shield or converter housing cover as applicable. 14. On vehicles with au to m atic transm ission, remove converter to flywheel attaching bolt. 15. Remove m ount "th ro u g h " bolts. 16. Remove bell housing bolts. 17. Lower vehicle on hoist. 18. Raise transm ission using floor jack. 19. A ttach engine lifting devices, raise engine. 20. Remove motor m ount to engine brackets. 21. Remove engine assembly. Installation 1. Position engine assembly in vehicle. 2. A ttach motor m ount to engine brackets and lower engine in place. 3. Remove engine lifting device. 4. Remove transm ission floor jack. 5. Raise vehicle on hoist. 6. Install m ount " th ro u g h " bolts. T orque to specifications. 7. Install bell housing bolts. Torque to specifications. 8. On vehicles w ith au to m atic transm issions, install converter to flywheel attach in g bolts. T orque to specifications. 9. Install flywheel splash shield of converter housing cover as applicable. Torque attaching bolts to specifications. 10. Install starter. 11. C onnect exhaust pipe at m anifold and converter bracket at transm ission rear mount. 12. Lower vehicle on hoist. 13. Reinstall power steering pum p and A /C compressor, if so equipped. 14. Connect: • A ccelerator linkage at inlet manifold. • Fuel line, from tank, at fuel pump. • Hoses at fuel vapor storage canister. • Vacuum line to power brake unit at manifold, if equipped. 15. Connect wires at: • S tarter Solenoid • G enerator • ?T R C Speed Switch • T R C Solenoid • T em perature Switch • Oil Pressure Switch • D istribotor 16. Install radiator and fanshroud and reconnect radiator and heater hoses. 17. Fill cooling system. 18. Fill crankcase w ith oil. See Section OB for specifications. 19. Install air cleaner. 20. Install hood. 21. Connect battery cables. NOTICE: To avoid possible arcing of battery, connect positive battery cable first. LIGHT TRUCK SERVICE MANUAL 6A 5-30 MARK IV 22. S ta rt engine, check for leaks and check timing. CRANKSAHFT APPLY SEALANT TO SHADED AREAS ONLY The crankshaft can be removed while the engine is disassembled for overhaul, as previously outlined or without complete disassem bly as outlined below. Removal 1. W ith the engine removed from the vehicle and the transm ission an d /o r clutch housing removed from the engine, m ount engine in stand and clam p securely. 2. Remove the oil dip stick and oil dip stick tube, (if applicable). 3. Rem ove the sta rtin g m otor, clutch assem bly (if equipped) and flywheel. 4. Remove the spark plugs. 5. Remove crankshaft pulley and torsional dam per. 6. Remove oil pan and oil pump. 7. Remove crankcase front cover, and if so equipped, remove tim ing chain and cam shaft sprocket. 8. Check the connecting rod caps for cylinder num ber identification. If necessary, m ark them. 9. Remove the connecting rod caps and push the pistons to top of bores. 10. Remove m ain bearing caps and lift crankshaft out of cylinder block. 11. Remove rear main bearing oil seal and m ain bearings from cylinder block and main bearing caps. Fig. 6A5-58--Sealing Bearing Cap 2. 3. 4. 5. Cleaning and Inspection 1. W ash crankshaft in solvent and dry with compressed air. 2. M easure dim ensions of m ain bearing jo u rn als and crankpins with a m icrom eter for out-of-round, taper or undersize. (See Specifications.) 3. Check crankshaft for run-out by supporting at the front and rear m ain bearings journals in "V " blocks and check a t the front and rear interm ediate journals with a dial indicator. (See Specifications.) 4. R eplace or recondition the cra n k sh a ft if out of specifications. 6. 7. 8. SPROCKET OR GEAR REPLACEMENT Remove crankshaft sprocket using Tool J 1619, install using Tool J -2 1058. Installation 1. Install rear m ain bearing oil seal in cylinder block and rear main bearing cap grooves. Install with lip of seal LIGHT TRUCK SERVICE MANUAL 9. tow ard front of engine. W here seal has two lips install lip with helix towards front of engine. Lubricate lips of seal with engine oil. Keep oil off parting line surface. Install m ain bearings in cylinder block and m ain bearing caps then lubricate bearing surface with engine oil. Install crankshaft, being careful not to dam age bearing surfaces. Apply a thin coat of brush-on type oil sealing com­ pound to block m ating su rface and corresponding surface of cap only (fig. 6A 5-58). Do not allow sealant on crankshaft or seal. Install main bearing caps with arrows pointing toward front of engine. T orque all except rea r m ain bearing cap bolts to specifications. Torque rear m ain bearing cap bolts to 10-12 lbs. ft. (14-16 N-m) then tap end of crankshaft, first rearw ard then forward with a lead ham m er. This will line up rear main bearing and crankshaft thrust surfaces. R etorque all m ain bearing cap bolts to specifications. M easure crankshaft end play with a feeler gage. Force crankshaft forward and m easure clearance between the front of the rear main bearing and the crankshaft thrust surface. Install flywheel and torque to specifications. A wood block placed between the crankshaft and cylinder block will prevent crankshaft from rotating. • Align dowel hole in flywheel with dowel hole in crankshaft. On vehicles equipped with autom atic transm issions, install flywheel w ith th e converter attaching pads towards transm ission. G ENERAL DATA: LE8 PISTON PIN .9895-.9898 D IA M E T E R 90° V -8 G A S O L I N E TYPE PRODUCTION DISPLACE MENT LITRE (*) 7.4 (W) .000 25-.0003 5 CLEARANCE SERVICE RPO LE8 BORE 4.250 STROKE 4 .0 0 0 COMPRESSION RA TIO 8.5:1 F IR IN G ORDER 1-8-4-3-6-5-7-2 DIAM ET ER SERVICE .002 M A X . O D C 0 1 .001 M A X . TAPER PF TION D IA M E T E R THRUST SIDE RELIEF SIDE TAPER SERVICE OUT OF RO UND PRODUCTIO N SERVICE .001 M A X . PRODUCTIO N .0 002 M A X . SERVICE .001 M A X . # 1 -2 -3 -4 M AIN BEARING CLEARANCE #■5 .0 0 2 4 .0 0 4 0 SERVICE C R A N K S H A F T END P L A Y PRODUCTION .0 0 3 0 -.0 0 4 0 SERVICE .0050 M A X . .001 3 -.0 0 2 5 PRODUCTION .001 M A X . P IS T O N : 2 .7 4 7 6 -2 .7 4 8 6 .0 0 0 2 M A X . .0005 M A X . .001 M A X . IN T E R F E R E N C E # 1 -2 -3 -4 2 .7 4 8 1 -2 .7 4 9 0 #5 4.2495-4.2525 PRODUCTION .0 0 1 3 -.0 0 2 1 CRANKSHAFT M AIN J O URNAL C Y L IN D E R BORE: OUT OF ROUND FIT IN ROD .001 M A X . D IA M E T E R CLEARANC E n . m . .0 0 1 4 .0 0 2 5 +U- '*0 .006-.010 2.20 00-2.199 0 PRODUCTION .0 0 0 5 SERVICE .001 M A X . PRO DUCTION .000 5 SERVICE .001 M A X . TAPER CRANKPIN P IS T O N R I N G : c o M p R PRODUC­ TION O 1 L TOP .0017-.0032 2ND .0017-.0032 SERVICE GAP PRODU C­ T IO N 2 O S S 1 GROOVE CLEAR­ ANCE TOP .010 - . 0 2 0 2ND .010 - . 0 2 0 SERVICE GROOVE CLEAR ANCE HI L I M I T P R O D U C T I O N +.001 PRODUCTION SERVICE HI L I M I T P R O D U C T I O N + .01 0 .0 0 5 - . 0 0 6 5 HI L I M I T P R O D U C T I O N +.001 PRODU CTION .0 1 5 -.0 5 5 SERVICE HI L I M I T P R O D U C T I O N + .01 0 GAP * VIN D e sig n a tio n OUT OF ROUND ROD BEARING CLEARANCE PRO DUCTION SERVICE ROD SIDE CLEARANCE .0 0 0 9 -0 0 2 5 .0030 M A X . .0 1 3 -.0 2 3 CAMSHAFT LOBE L IF T ± .002 IN T A K E .2 343 E X HAUST .2530 J O URNAL D IA M E T E R 1 .9 4 8 2 -1 .9 4 9 2 .0 0 2 5 .0 0 3 5 V A L V E SYSTEM LE8 L IF T E R H Y D R A U L IC ROCKER A R M R A T IO 1.70:1 VALVE LASH 8 0 LB . IN. 80 LB. IN. EXHAUST FROM ZERO LASH O I L P A N ( T O F R O N T C O V E R ) ..................... 55 LB . IN. O I L P U M P C O V E R ........................................... 80 LB . IN . 45° 46° .002 M AX. C O V E R .................................... 50 LB . IN. C A M S H A F T S P R O C K E T ................................. ROCKER ARM 20 LB . FT. O I L P A N T O C R A N K C A S E ( 5 / 1 6 - 1 8 ) ............ 13 5 LB . IN. C L U T C H P R E S S U R E P L A T E .......................... 30 LB . FT. D I S T R I B U T O R C L A M P .................................... 25 L B . FT. F L Y W H E E L H O U S I N G .................................... 3 0 LB . FT. IN TA K E 1 /3 2 -1 /1 6 EXHAUST 1 /1 6 -3 /3 2 M A N IF O L D ( E X H A U S T ) ................................. 20 LB . FT. IN T . .0010-.0027 M A N IF O L D ( I N L E T ) ........................................ 30 LB . F T. EXH. .001 2-’. 0029 W A T E R O U T L E T ............................................. 30 LB . FT. W A T E R P U M P .................................................. 30 LB. FT. P R O D U C T IO N S E R V IC E HI L IM IT + .001 IN . + .0 0 2 E X . C O N N E C T IN G R O D C A P ............................... 50 LB. FT. H E A D ........................................... 8 0 LB . FT. O I L P U M P ......................................................... 6 5 LB . FT. C Y L IN D E R FREE L E N G T H SPRING (OUTER) 80 LB . IN. O I L F I L T E R B Y P A S S V A L V E ........................ SE A T R U N O U T VALVE F R O N T C O V E R ........................ F L Y W H E E L H O U S I N G C O V E R ..................... ONE TURN DOWN SE AT A N G L E ( IN T . & EX H .) STEM CLEARANCE CRANKCASE IN T A K E FACE A N G L E ( IN T . & E X H .) SE AT W ID T H TORQUE SPECIFICATIONS PRESSURE LBS. @ IN. 2.12 CLOSED 8 4 -9 6 @ 1.80 OPEN 2 1 0 -2 3 0 @1.40 IN S T A L L E D H E I G H T ± 1/32" 1-51/64 FREE L E N G T H 1.86 APPROX. # O F COILS 4 DAM PE R R O C K E R A R M S T U D ...................................... 5 0 LB . FT. FLYW HEEL 6 5 LB . FT. M A IN .................................................... B E A R I N G C A P ...................................... 110 LB . FT. T E M P E R A T U R E S E N D I N G U N I T ................... 20 LB . FT. T O R S I O N A L D A M P E R .................................... 8 5 LB . FT. O I L F I L T E R ............................................. .. 25 LB . FT. O IL PA N D R A IN 20 LB . F T. SPA R K PLUG PLUG ................................. ................................................17-27 LB . FT. V8-D IE SE L 6A6-1 Oil P a n ............................................................................ Oil P um p........................................................................ Connecting Rod and P is to n ...................................... Rod B earings................................................................ Rod Assem bly............................................................... P isto n .............................................................................. Rod and P isto n ............................................................. Piston P in s ..................................................................... C rankshaft Pulley........................................................ B alancer......................................................................... Front C o v e r................................................................... Oil S e a l........................................................................... Timing Chain and G ears............................................ C am shaft, Injection Pum p Drive and Driven Gears . . '. . . ............................................................. C am shaft and Injection Pum p Driven G ear B earings............................................................................ U N IT R E P A IR .............................................................. E ng ine............................................................................. C ra n k sh a ft..................................................................... M ain B earings.............................................................. M ain Bearing Upper Oil S e a l.................................. R ear M ain Bering Lower Oil S e a l......................... Flex P la te ....................................................................... Engine Oil Dipstick and G u id e s.............................. Specifications................................................................... 6A6-26 6A6-26 6A6-27 6A6-27 6A6-28 6A6-28 6A6-30 6A6-31 6A6-32 6A6-32 6A6-32 6A6-34 6A6-34 SECTION 6A6 5.7 L (N) 350 Diesel Contents G eneral D escription....................................................... On Vehicle Service........................................................ Injection P u m p ............................................................. T hrottle Shaft Seal R ep lacem ent............................ Oil Filter B ase.............................................................. Engine M ounting......................................................... Exhaust M anifolds...................................................... Checking or A djusting T im in g ................................ Compression T e s t........................................................ Linkage A d justm en ts................................................. Transmission Vacuum R egulator V alve................ C hecking Injection Pum p Housing Fuel P re s s u re ......................... Injection Pum p Fuel L ines........................................ Injection Pump and L in e s......................................... Injection Pum p A dapter and S e a l.......................... Valve C o v e r.................................................................. Intake M anifold............................................................ Rocker Arm Assemblies............................................. Valve L ifters................................................................. Injection N o z z le .......................................................... Cylinder Head and G a s k e t....................................... Valves and Springs with H ead R em ov ed.............. Valve Guide B o re ........................................................ Replacing Valve Spring (H ead on E ngine).......... 6A6-1 6A6-4 6A6-4 6A6-4 6A6-6 6A6-6 6A6-7 6A6-8 6A6-8 6A6-8 6A6-9 6A6-10 6A6-11 6A6-12 6A6-13 6A6-14 6A6-14 6A6-16 6A6-16 6A6-19 6A6-22 6A6-23 6A6-24 6A6-25 6A6-34 6A6-34 6A6-37 6A6-37 6A6-37 6A6-39 6A6-40 6A6-41 6A6-41 6A6-41 6A6-44 GENERAL DESCRIPTION ENGINE CONSTRUCTION spring loaded and calibrated to open at a specified fuel pressure, and are not adjustable. T he engine is a 5.7 L iter V-8 four cycle diesel fuel engine. C ylinder num bers 1, 3, 5 and 7 are on the left bank. C ylinder num bers 2, 4, 6 and 8 are on the right bank. The firing order is 1-8-4-3-6-5-7-2. T he m ajor difference between a gasoline engine and the diesel is in the cylinder heads, com bustion cham ber, fuel distribution system, air intake m anifold and m ethod of ignition. The cylinder block, crankshaft, main bearings, rods, pistons and pins are of a heavier construction because of the high compression ratio required to ignite diesel fuel. Diesel ignition occurs because of h eat developed in the com bustion ch am b er during compression. This elim inates the need for spark plugs and high voltage ignition. Intake and exhaust valves in the cylinder heads operate the sam e as in a gasoline engine, but are of a special design and m aterial for diesel operation. The stainless steel pre­ cham ber inserts in the cylinder head com bustion cham bers are serviced separately from the head. W ith the cylinder head removed they can be pushed out after removing the glow plugs and injection nozzles. Glow plugs and nozzles are threaded into the cylinder head. The injection nozzles are Fi9* 6A6-1--Injection Pump-Cutaway LIGHT TRUCK SERVICE MANUAL 6A 6-2 V8 - DIESEL Fig. 6A6-2--Nozzle Cutaway (Exec. Calif.) Fig. 6A6-4--System Fuel Circuit injects a m etered am ount of fuel to each cylinder at the proper time. The eight high pressure delivery pipes from the pump to the injection nozzle in each cylinder are the same length to prevent any difference in tim ing, cylinder-tocylinder. The fuel injection pum p provides the required tim ing advance under all operating conditions. Engine R PM is controlled by a rotary fuel m etering valve. Pushing down on the accelerator pedal moves the th rottle cable to open the m etering valve and allow more fuel to be delivered. The injection pum p also has a low pressure transfer pum p to deliver fuel from the fuel line to the high pressure pump. INLET FITTING NOZZLE GASKET NOZZLE BODY The fuel filter is located between the m echanical fuel pum p and the injection pump. The diaphragm type m echan­ ical fuel pum p is m ounted on the right side of the engine and driven by a cam on the c ran k sh a ft. The fuel ta n k is connected by fuel pipes and hoses to the m echanical fuel pump. Excess fuel returns from the fuel injection pum p to the fuel tank through pipes and hoses. Fig. 6A6-2a--Nozzle Cutaway (Calif.) GOVERNOR SPRING HOUSING PRESSURE REGULATOR METER NG VALVE I k VENT WIRE ASSEMBLY HEAD PRESSURE TRANSFER PRESSURE TAP HOIf PLUG CAM / BALL CHECK ' ASSEMBLY ^GOVERNOR; AUTOMATIC ADVANCE MECHANISM HQUSW g LUBEI CHARGING PASSAGE FILTER DELIVERY TRANSFER PUMP TRANSFER PUMP PRESSURE CIRCUIT M HOUSING PRESSURE CIRCUIT NOZZLE E Z 3 INLET PRESSURE AND RETURN OIL CIRCUIT Fig. 6A6-3--Pump Fuel Circuit FUEL SYSTEM (Figs. 6A6-1, 2, 2a, 3&4) The diesel fuel injection pum p is m ounted on top of the engine. It is gear driven off the cam shaft and turns at cam shaft speed. It is a high pressure rotary pum p that LIGHT TRUCK SERVICE MANUAL The H PC A feature is designed to advance the injection tim ing about 3° during cold o peration. This circu it is actuated by a tem perature switch on the right rear head bolt. The switch is calibrated to open the circuit at 125°F. Below the switching point, housing pressure is decreased from 10 psi to zero which advances the tim ing 3°. Above 125°, the switch opens de-energizing the solenoid and the housing pressure is returned to 10 psi. T he fast idle solenoid is energized by the sam e switch. T he switch again closes when the tem perature falls below 95°F. PU R PO SE : FILTER HIGH PRESSURE DISCHARGE CIRCUIT ■ HOUSING PRESSURE COLD ADVANCE (HPCA) (IF EQUIPPED) 1. Emission Control device. 2. B etter cold starts. 3. Improves idle and noise when cold. W hen changing the fuel filter or when the car has run out of fuel, disconnect the connector from the tem pera­ ture switch and jum per connector term inals. This will aid in purging air from the pump. (This procedure is necessary only on a hot engine, as the circuit will always be closed when the engine is cold.) V 8 - DIESEL HOUSING PRESSURE COLD ADVANCE TERMINAL THROTTLE SHAFT ADVANCE CAM“ PRESSURE TAP PLUG AND SEAL FUEL SOLENOID . TERMI NAL / tfS k V ft GUIDE S T U D - ^ ^ v PS^TH RO TTLE SHAFT PIN " ADVANCE CAM ^ ^ A C T U A T I N G ARM Fig. 6A6-5--lnjection Pump Housing Right Side View DIESEL FUEL HEATER, OPTION K07 (Fig. 6A6-27) This cold w eather option consists of an inline diesel fuel heater and an engine coolant heater. The diesel fuel heater is a therm ostatically controlled electrical resistance type heater designed to heat the fuel before it enters the engine m ounted fuel filter to reduce the possibility of wax plugging the filter when the fuel tem pera­ ture is 20°F or lower. Twelve volts are directed to the heater whenever the ignition is in the run position. The heater consists of a strip spiral wound around the fuel pipe. A bim etal therm al switch senses the fuel tem perature and closes and electrical circuit when the fuel tem perature is about 20°F. The circuit opens at 50°F. The fuel tank filter sock has a bypass valve which opens when the filter is covered w ith wax allowing fuel to flow to the heater. ENGINE LUBRICATION SYSTEM (Fig. 6A6-6) The engine oil pan forms a reservoir for engine oil to provide lubrication and also hydraulic fluid to operate the valve lifters. Oil pressure for lubrication is furnished by a gear type oil pum p th at is bolted to the rear m ain bearing l. O IL PICK-U P LIFTER FEED 3. ROCKER ARM VALVE TIP FEED 4. SPLASH LUBE TO TIM IN G CHAIN FUEL PUMP CAM & DIST. & OIL PUMP DRIVE LEFT MAIN GALLERY 5. FEED 6. CAM BEARING FEED 7. M A IN BEARING FEED ROD BEARING FEED 9. INJECTION PUMP DRIVE BEARING FEED z RIGHT MAIN GALLERY VACUUM PUMP AND OIL PUMP DRIVE 6A 6-3 cap and driven by the cam shaft gear through a hexagonal drive shaft. Oil enters the pum p through a screened inlet located near the bottom rear of the oil pan. The pressurized oil from the pum p passes through the oil filter located on the right rear side of the engine block. The oil filter base has a by-pass valve which, in the event of filter restriction, will open at 5.5 to 6.5 psi (38 to 45 kPa). Engine oil is directed to the oil cooler, located in the radiator, then from the cooler to the filter base. The oil then is directed back to the engine oil galleries. A by-pass valve in the filter base allows continuous oil flow to the engine in case of cooler line or cooler restriction. This by-pass valve opens at about 12 psi (83 k P a). Oil then enters th e rig h t oil gallery w here it is distributed to the five m ain bearings. The right bank valve lifters receive oil from this gallery from eight feed holes th at intersect the gallery. The five cam shaft bearings are lubricated from vertical passages intersecting the main bearing oil passages. A t the front m ain bearing a third passage connects the right main oil gallery to the left gallery which then feeds the left bank of valve lifters. The injection pum p driven gear is lubricated by oil directed th ro u g h a passage from the top of th e front cam shaft bearing. An angled passage in the shaft portion of the driven gear then directs the oil to the rear driven gear bearing. The engine oil pressure warning light switch is con­ nected to the front of the left oil gallery. The switch is calibrated to turn on the instrum ent panel w arning light when engine oil pressure is too low. The switch, norm ally closed, is set to open a t 2-6 psi (14 to 41 kPa). The rear oil gallery plug has a .040" (1m m ) orifice to help purge contam inants from the gallery and to lubricate the vacuum pum p driven gear. A t the front end of the right gallery, a small orifice sprays oil to lubricate the fuel pump eccentric cam on the crankshaft and the tim ing chain. The vacuum pum p drive gear is lubricated by oil from the left rear oil gallery. The rocker arm s and valve tips are lubricated by oil furnished through the hydraulic lifters and hollow pushrods. A disc valve in the lifter m eters oil to the push rods. The connecting rod bearings are oiled by constant oil flow from passages drilled through the crankshaft, connect­ ing the main journals to the rod journals. A groove around each m ain bearing furnishes oil to the drilled crankshaft passages. Oil returns to the oil pan reservoir from the rocker arm s through passages at each end of the cylinder heads. Oil from the valve lifter co m p artm en t retu rn s th ro u g h clearan ce holes in the lower portion of the com partm ent near the cam shaft. The tim ing chain com partm ent drains directly into the oil pan. I f FT MAIN GALLERY To check engine oil pressure, See Fig. 6A6-7. a COOLING Fig. 6 A 6 -6 -E n g in e Lubrication Engine cooling is the same as used in gasoline engines except the radiator tank has two oil coolers. One is con­ nected to the transm ission, the other one connects into the oil filter base. LIGHT TRUCK SERVICE MANUAL 6A 6-4 V 8 - DIESEL ignition key is turned to the " R U N " position prior to starting the engine. They pulse a short tim e after starting, then autom atically turn off. (The circuit and operation is covered in detail under the subject-Diesel Electrical.) Two 12-volt batteries connected in parallel are required for the higher electrical load due to the glow plugs and starter. The starter is larger and designed to crank the engine a t least the 100 R PM required for starting (240 R PM if engine is hot). The two batteries, one on each side in the engine com part­ ment, provide the required capacity and elim inates the need for a single double size special battery. A standard genera­ tor supplies charging current to both batteries a t the same time. There are no switches or relays in the charging circuit. 1. ENGINE AT OPERATING TEMPERATURE. 2. TRANSMISSION IN "NEUTRAL" POSITION. _ ^ 3 . OIL PRESSURE SHOULD BE: AT SLOW IDLE - 7 PSI MIN. 1500 - 3000 R P M -35 PSI MIN. \\ \ \ WK Fig. 6A6-7--Checking Engine Oil Pressure ENGINE CLEANING Do not clean the engine until it has cooled down to surrounding tem perature. Spraying w ater or engine clean­ ing fluid on the diesel injection pum p when it is warm or hot will dam age the pump. ELECTRICAL Eight glow plugs are used to heat the pre-cham ber to aid in starting. They are 6 volt heaters th at pulse when the ON VEHICLE SERVICE Reinstall the guide stud with a new washer making certain th a t the upper extension of the m etering valve spring rides on top of the guide stud. Torque the guide stud to 9.5 N-m (85 in. lbs.) O vertorquing the guide stud may strip the alum inum threads in the housing (Figs. 6A6-5 and 6A6-8). INJECTION PUMP ON VEHICLE SERVICE There are three areas on the injection pum p where leaks can be corrected w ithout removing the pum p from the engine. These are cover seal, guide stud seal and throttle shaft seal. Pump Cover Seal and/or Guide Stud Seal Replacement 9. Hold the throttle in the idle position. 10 . Install new pum p cover seal. M ake sure the screws are not in the cover and position the cover about 1/4 inch forw ard (tow ard shaft end) and about 1/8 inch above the pum p (Fig. 6A 6 -10). 1. Disconnect the negative cables from both batteries. 2. Rem ove th e a ir clean er and air crossover. Install screens J-26996-2 (C alif.) or J-26996-10 (Excl. Calif.) in the intake m anifold. 3. D isconnect the injection pum p fuel solenoid and (housing pressure cold advance if equipped) wires and the fuel return pipe. 4. Clean the injection pum p cover, upper portion of the pum p and the guide stud area (Fig. 6A 6-5). Place several rags in engine valley to catch fuel. 11 Move the cover rearw ard and downward into position, being careful not to cut the seal and reinstall the cover screws. Be careful not to drop or lose flat washer and internal lock w asher with each screw. Flat washer must be against pum p cover. T orque to 3.7 N-m (33 in. lbs.) 12. Reconnect the negative cables to both batteries. M I N - M A X GOVERNOR ASSEM BLY 5. Remove injection pum p cover and remove screws from the cover. IDLE GOVERNOR S P R IN G NOTICE: E x trem e care m ust be exercised to keep foreign m aterial out of the pum p when the cover is off. If any objects are dropped into the pump, they m ust be removed before the engine is started or injection pump dam age or engine dam age could occur. ST E PS 6, 7 and 8 A R E FO R G U ID E ST U D SEA L R EPLA CEM EN T ONLY. 6. Observe position of m etering valve spring over the top of the guide stud. T his position m ust be exactly duplicated during reassem bly (Fig. 6A6-8). 7. Remove the guide stud and washer. N ote location of parts prior to removal. LIGHT TRUCK SERVICE MANUAL Fig. 6A 6 -8 -ln je c tio n Pump Cover Removed V 8 - DIESEL 13. T urn the ignition switch to the run position and touch the pink solenoid wire to the solenoid. A clicking noise should be heard as the wire is connected and discon­ nected. If this clicking is not observed, the linkage may be jam m ed in a wide open throttle position and the engine M U ST N O T be started. If clicking is observed, connect the pum p solenoid and (housing pressure cold advance if equipped) wires (Fig. 6A 6-5), then proceed to step 16. a. Install tool J-29601 over the throttle shaft with slots of tool engaging pin. Put the spring clip over the throttle shaft advance cam and tighten the wing nut. W ithout loosening the wing nut, pull the tool off the shaft. (This provides the proper alignm ent on reas­ sembly, Fig. 6A6-9). b. Drive the pin from the throttle shaft and remove the throttle shaft advance cam and fiber washer. Remove any burrs from the shaft th at may have resulted from pin removal (Fig. 6A6-5). If the injection pump does not have an Advance Cam A ctuating Arm: a. Drive the throttle shaft drive pin out of shaft and remove the throttle retaining ring and fiber washer. Remove any burrs from the shaft th at may have resulted from pin removal. 8. Clean the injection pum p cover, upper portion of the pump, the throttle shaft and the guide stud area. (Fig. 6A6-5). Place several rags in the engine valley to catch fuel. 9. Remove injection pum p cover and remove screws from the cover. 14. Remove the cover. G round the solenoid lead (opposite the hot lead) and connect the pink wire. W ith the ignition switch in the run position, the solenoid in the cover should move the linkage. If not, the solenoid must be replaced. M inim um voltage across solenoid term i­ nals m ust be 12.0. 15. Reinstall the cover and repeat Step 10. 16. R einstall the fuel return pipe and the throttle cable and return springs. 17. S ta rt the engine and check for leaks. 18. Idle roughness may be observed due to the air in the pump, give it plenty of tim e to purge which it will do by allowing the engine to idle. It m ay be necessary to shut the engine down for several m inutes to allow air bubble to rise to the top of the pum p where they will be purged. 19. Remove the intake m anifold screens, then reinstall the air crossover and air cleaner. 10. Throttle Shaft Seal Replacement 1. Disconnect the negative cables from both batteries. 2. Rem ove the air cleaner and air crossover. Install screens J-26996-2 (Calif.) or J-2 6 9 9 6 -10 (Exc. Calif.) in the intake manifold. 11. 12. 3. D isconnect the injection pum p fuel solenoid and (housing pressure cold advance if equipped) wires and the fuel return pipe (Fig. 6A6-5). 4. Remove the vacuum regulator valve, the throttle rod and return springs. 13. 5. Remove the throttle cable bracket. 6. If injection pump is equipped with an Advance Cam A ctuating Arm: 14. THROTTLE SHAFT ADVANCE CAM .005" CLEARANCE THROTTLE SHAFT PIN J-29601 15. 16. 17. ADVANCE CAM ACTUATING ARM Fig. 6A6-9--lnjection Pump W ith Tool J-29601 Installed 6A 6-5 18. 19. NOTICE: E xtrem e care m ust be exercised to keep foreign m aterial out of the pump when the cover is off. If any objects are dropped into the pump, they must be removed before the engine is started or injection pump dam age or engine dam age could occur. Observe position at m etering valve spring over the top of the guide stud. T his position m ust be exactly duplicated during reassembly. (Fig. 6A6-8). Remove the guide stud and washer. N ote location of parts prior to removal. (Fig. 6A6-5) R otate the m in-m ax governor assembly up to provide clearance and remove from the throttle shaft. (Fig. 6A6-8). If idle governor spring becomes disengaged from throttle block, it m ust be reinstalled with tightly wound coils toward throttle block. Remove the throttle shaft assembly and exam ine the shaft for unusual wear or dam age, replace if required. It may be necessary to loosen the nuts at the injection pump m ounting flange and rotate the pum p slightly to allow the throttle shaft assembly to clear the intake manifold. E xam ine th e th ro ttle sh aft bushings in the pum p housing for any evidence of dam age or unusual wear. Remove the pum p and send to the local Roosa M aster dealer if bushing replacem ent is necessary. Remove the throttle shaft seals. Do not attem pt to cut the seals to remove, as nicks in the seal seat will cause leakage. Install new shaft seals using care not to cut the seals on the sharp edges of the shaft. Apply a light coating of clean chassis grease on the seals. C arefully slide the throttle shaft back into the pump to the point where the m in-m ax governor assembly will slide back onto the throttle shaft. (Fig. 6A6-8) R o ta te the m in-m ax governor assem bly dow nw ard, hold in position and slide the th ro ttle shaft and governor into position. Install a new fiber washer, the throttle shaft advance cam, (do not tighten cam screw at this tim e), and a new LIGHT TRUCK SERVICE MANUAL 6A 6-6 V8 - DIESEL throttle shaft drive pin on pumps w ithout actuating arm install a new throttle shaft retaining ring (Fig. 6A6-5) 20. On pumps with the A dvance C am A ctuating Arm: a. Align the throttle shaft advance cam so tool J-29601 can be reinstalled over the throttle shaft, pin in the slots and the spring clip over the advance cam. b. Put a .005" feeler gage between the cam and the fiber w asher. T ig h ten th e cam screw and rem ove tool J-29601. 21. Reinstall the guide stud with a new washer, m aking certain th at the upper extension of the m etering valve spring rides on top of the guide stud. Torque the guide stud to 9.5 N-m (85 in. lbs.) O vertorquing the guide stud may strip the alum inum threads in the housing (Figs. 6A6-5 and 6A 6-9) 22. Hold the throttle in the idle position. 23. Install new pum p cover seal. M ake sure the screws are not in the cover and position the cover about 1/4 inch forward (tow ard shaft end) and about 1/8 inch above the pum p (Fig. 6A 6-10). 24. Move the cover rearw ard and downward into position, being careful not to cut the seal and reinstall the cover screws. Be careful not to drop and lose flat washer and internal lock w asher with each screw. Flat washer must be against pum p cover. Torque to 3.7 N-m (33 in. lbs.). Install vacuum regulator valve. 25. Reconnect the negative cables to both batteries. 26. T urn the ignition switch to the run position and touch the pink solenoid wire to the solenoid. A clicking noise should be heard as the wire is connected and discon­ nected. If this clicking is not observed, the linkage may be jam m ed in a wide open throttle position and the engine M U S T N O T be started. If clicking is observed, connect the pum p solenoid and housing pressure cold advance wires (Fig. 6A 6-5), then proceed to step 30. 27. Remove the cover. G round the solenoid lead opposite the hot lead and connect th e pink wire. W ith the ignition switch in the run position, the solenoid in the cover should move the linkage. If not the solenoid must be replaced. M inim um voltage across solenoid term i­ nals m ust be 12.0. 28. R einstall the cover and repeat Step 27. 29. R einstall throttle cable bracket and throttle rod. 30. R einstall the throttle cable and return springs. M ake sure the tim ing m ark on the pum p and adapter are aligned and m ake sure the nuts attaching pump to adapter are tight. Install fuel return pipe. 31. S ta rt the engine and check for leaks. 32. Idle roughness m ay be observed due to the air in the pump, give it plenty of tim e to purge which it will do by allowing the engine to idle. It m ay be necessary to shut the engine down for several m inutes to allow air bubble to rise to the top of the pump where they will be purged. 33. A djust vacuum reg u lato r valve. See "V A C U U M R E G U L A T O R V A LV E A D J U S T M E N T ". 34. Remove the intake m anifold screens, then reinstall the air crossover and air cleaner. LIGHT TRUCK SERVICE MANUAL LONGER BOLT GASKET Fig. 6 A 6 -ll--O il Filter Base OIL FILTER BASE (Fig. 6A6-11) Removal 1. 2. 3. 4. 5. 6. Remove oil cooler lines. Bend exhaust manifold lock tabs away from bolts. Hoist vehicle. Disconnect exhaust system from exhaust manifold. Remove exhaust manifold. Remove oil filter base retaining bolts and remove base. Installation If a new oil filter elem ent is installed, add one q u art of oil. Clean sealing surfaces and re-bend manifold bolt lock tabs. S tart engine, check for leaks and proper oil level. Torque oil filter base attaching bolts to 35 lbs. ft. (47N -m ) and exhaust manifold bolts to 25 lbs. ft. (34N -m ). ENGINE MOUNTING R efer to Fig. 6A6-12. V 8 - DIESEL 6A 6-7 Fig. 6A6-12--Engine Mounts EXHAUST MANIFOLD Removal and Installation (Left Side) 1. Remove air cleaner and install air crossover screened cover J-26996-1. 2. Remove lower generator bracket. 3. Hoist vehicle. 4. Remove crossover pipe. 5. Lower vehicle. 6. Remove exhaust manifold from above. To install, reverse removal procedure. R efer to Fig. 6A 6 -13 for proper bolt torque. Removal and Installation (Right Side) 1. Hoist vehicle. Fig. 6A6-13--Exhaust Manifold Bolts 2. Remove crossover pipe. 3. Remove exhaust manifold. To install, reverse removal procedure. See figure 6A613 for proper bolt torque. LIGHT TRUCK SERVICE MANUAL 6A 6-8 V 8 - DIESEL COMPRESSION TEST To determ ine if the valves or rings are the cause of low com pression, a test should be m ade to determ in e the cylinder compression pressure. W hen checking compression, the batteries should be at or near full charge. The lowest reading cylinder should not be less than 70% of the highest and no cylinder reading should be less than 275 p.s.i. (1900 kPa). 1. Remove air cleaner then install air crossover cover J-26996-1. 2. Disconnect the wire from the fuel solenoid term inal of the injection pump. 3. Disconnect wires from glow plugs then remove all glow plugs. 4. Screw the compression gage J-26999 into the glow plug hole of the cylinder th at is being checked. 5. C rank engine. This should be done with six "puffs" per cylinder. • N orm al-Com pression builds up quickly and evenly to specified compression on each cylinder. • Piston R ings Leaking-C om pression low on first stroke tends to build up on following strokes but does not reach normal. NOTICE: Do not add oil to any cylinder to compression test as extensive dam age may result. LINKAGE ADJUSTMENTS (Figs. 6A6-14, 15 and 16) Throttle Linkage 1. Check timing, adjust if needed. CHECKING OR ADJUSTING TIMING Checking (Fig. 6A6-14, 14a) For the engine to be properly timed, the m arks on the top of the injection pum p adapter and the flange of the injection pump m ust be aligned. The engine m ust be off when the timing is reset. Adjusting If the marks are not aligned, adjustm ent is necessary. 1. Loosen the th re e pum p retain in g nuts w ith tool J-26987. 2. Align the m ark on the injection pum p with the m arks on the adapter and tighten nuts. Torque to 35 lbs. ft. (47N-m ). • Use a 3/4" open end wrench on the boss at the front of the injection pum p to aid in rotating the pum p to align the marks. 3. A djust th ro ttle rod (See "L IN K A G E A D JU S T M E N T "). 2. If equipped with cruise control, remove clip from cruise control throttle rod and disconnect the rod from the throttle lever assembly. 3. Disconnect the transm ission T.V. (or detent) cable from the throttle assembly. 4. Loosen the lock nut on the pum p rod and shorten several turns. FUEL ELB0W SHUT-OFF SO LE N O ID (H ID D EN ) SLOW IDLE A DJU ST M EN T SCREW FUEL RETURN H O U S IN G P R E S S U R E L IN E CONNECTOR COLD A D V A N C E T ER M IN A L (H ID D EN ) P R E-SET DO NOT A D J U S T P R E S S U R E TAP PLUG & SEA L THROTTLE LEVER Fig. 6A6-15--lnjection Pump Slow Idle Screw LIGHT TRUCK SERVICE NANUAL V 8 - DIESEL 6A 6-9 3. Loosen the vacuum regulator valve injection pump bolts. 4. Install J-2 6 7 0 1-15 carburetor angle gage adapter to the injection pum p throttle lever. Place angle gage J-2 6 7 0 1 on adapter. 5. R otate throttle lever to the wide open throttle position and set angle gage to zero degrees. (Fig. 6 A 6 -17). 6. C enter bubble in level. 7. Set angle gage to 58 degrees. 8. R otate throttle lever so level bubble is centered (Fig. 6A6-18). 9. A ttach vacuum source such as J-23738 vacuum pump to Port A. Install vacuum gage to Port B. Apply 18-22 inches of vacuum to Port A, Fig. 6 A 6 -19. 10. R otate vacuum valve clockwise to obtain 8.5 to 9.0 inches of vacuum. 5. R otate the lever assembly to the full throttle position and hold in th at position. 6. Lengthen the pum p rod until the injection pum p lever ju st contacts the full th ro ttle stop. 7. Release the lever assem bly and tighten the pum p rod lock nut. 8. Remove the pump rod from the lever assembly. 9. Reconnect the transm ission T.V. (or detent) cable. 10. Depress and hold the m edal lock tab on the cable upper end. Move the slider through the fitting in the direction away from the lever assem bly until the slider stops against the m etal fitting. 11. Release the m etal tab, rotate the lever assembly to the full throttle stop and release the lever assembly. 12. Reconnect the pum p rod (and cruise control throttle rod, if so equipped). 13. Remove the connector from the fast idle switch a n d bridge the harness connector with a jum per. Do not allow the jum per to touch ground. 11. Tighten vacuum valve bolts. Remove vacuum source and vacuum gage. 12. Install throttle rod to bellcrank. 13. Remove screened covers, then install air crossover. Vacuum Regulator Valve Removal 1. Remove the two vacuum hoses from the valve noting the location of the vacuum hoses. 2. Remove the two (2) attaching bolts. Installation: 1. Install the valve following the “Vacuum Regulator Valve Adjustment Procedure.” 2. Attach the two vacuum hoses to the valve. Put the hose from the vacuum pump to the inboard port and the hose to the transmission on the outboard port. 14. W ith the driving wheels blocked and the parking brake on, sta rt the engine and adjust the solenoid (energized) to th e specification listed on th e Em ission C ontrol Inform ation Label. 15. Check and adjust the slow idle speed with the engine at operating tem perature. To check idle speeds, it will be necessary to insert the probe of the m agnetic pickup tach, J-26925, in the tim ing indicator hole. 16. W ith the driving wheels blocked and the parking brake on, adjust the slow idle screw on the injection pum p to the specification shown on the emission control label. 17. If equipped with cruise control, adjust the servo throttle rod to m inim um slack (engine off) then put clip in first free hole closest to the bellcrank, but within the servo bail. Vacuum Regulator Valve Adjustment 1. Rem ove air crossover and in stall screened covers J-26996-2 (C alif.) or J-26996-10 (Exc. C alif.) on intake manifold. 2. Remove throttle rod from throttle lever. Vacuum Adjustment LIGHT TRUCK SERVICE MANUAL 6 A 6-10 V8 - DIESEL 3. Put the seal from the pressure tap plug on the pressure tap adapter J-29382, then screw the adapter into the pump housing. 4. Screw pressure tap adapter J-28526 into pressure tap adapter J-29382 then attach a low pressure gage to the adapter. 5. Install m agnetic pick-up tachom eter J-26925. 6. Check the pressure with the engine running at 1000 R PM (P A R K ), parking brak e on, drive wheels blocked. The pressure should be 8-12 PSI (55-83 kPa) with not more than 2 PSI (14 kPa) fluctuation. 7. If equipped with H PC A and the pressure is zero, check the operation of the houing pressure cold advance as follows: a. Remove the electrical connector from the housing pressure cold advance term inal, Fig. 6A6-5. If the pressure rem ains zero, remove the injection pump cover and check the operation of advance solenoid. If it is binding, free up or replace parts as needed. b. If the pressure becam e norm al with lead off, check the operation of the te m p e ra tu re switch on the cylinder head bolt. See "D iesel E lectrical". 8. If the pressure is still incorrect, replace the fuel return line connector assembly. If the pressure is too high, the fuel retu rn system m ay be restricted . Remove the return line at the injection pump. Install a fitting and short piece of hose to allow the return flow to em pty into a small container. 9. If th e pressure is lower th an before, correct the restriction in the fuel line. 10. If still to high, replace the fuel return line connector assembly. 11. If it rem ains too high, remove the injection pump for repair. 12. Remove the tachom eter, pressure gage, and adapters. 13. Put a new pressure tap plug screw seal on the pressure tap plug, then screw in the tap plug. 14. Remove screened covers, then install air crossover. Fig. 6A6-19--lnstrument Hook Up Points CHECKING INJECTION PUMP HOUSING FUEL PRESSURE - ENGINE WARM 1. Rem ove air crossover and install screened covers J-26996-2 (C alif.) or J-26996-10 (Exc. Calif.). 2. Remove the pressure tap plug (Fig. 6A 6 -15). LIGHT TRU CK SERVICE MANUAL V 8 - DIESEL 6A6-11 BREATHER CAP AND VALVE ASSY. Removal All lines may be removed w ithout removing injection pump. It is not necessary to use a back-up wrench when removing the lines from pump. 1. Remove air cleaner. (Fig. 6A6-20 and 6A6-21). 2. Remove filters and pipes from valve covers and air crossover. 3. Remove air crossover (Fig. 6A6-22, 6A6-23) and cap intake manifold with J-26996-2 (Calif) and J-2699610 (exc. Calif) screened covers. 4. Remove injection pum p line clamps. C ap open lines, nozzles, and pum p fittings. Use a back-up wrench on the nozzle upper hex to prevent a fuel leak. Installation INJECTION PUMP FUEL LINES (Fig. 6A6-14,14a) W hen lines are to be removed, clean all line fittings thoroughly before loosening. Im m ed iately cap all lines, nozzles and pum p fittings to m aintain cleanliness. 1. In stall new injection pum p line, install loose then torque both ends. T orque pum p end to 35 lbs. ft. (47N-m ) and nozzle end to 25 lbs. ft. (34 N-m ). Use a back-up wrench on the nozzle upper hex to prevent nozzle dam age. Then install clamps. • If several lines are to be replaced, sta rt with the bottom lines. 2. S tart engine and check for fuel leaks. LIGHT TRUCK SERVICE MANUAL 6A 6-12 V8-D IE SE L 3. Rem ove screened covers from intak e m anifold and install air crossover. 4. Connect pipes to flow control valve in air crossover and ventilation filters in the valve covers. (Fig. 6A6-24 and 6A6-25). 5. Install air cleaner. INJECTION PUMP AND LINES Removal 1. Remove air cleaner. 2. Remove filters and pipes from valve covers and air crossover. 3. Remove air crossover and cap intake m anifold with J-26996-2 (C alif) or J-26996-10 (Exc. Calif.) screened covers. 4. Disconnect throttle rod and return spring. (Fig. 6A6-16 and 6A6-26). 5. Remove bellcrank. 6. Remove throttle and T.V. cables from intake manifold brackets. Position cable away from engine. Fig. 6A6-28--Fuel Return Lines (Exc. Calif.) 20 FT. LBS. FUEL FILTER FUEL PUMP TO FILTER PIPE 7. Remove lines to fuel filter, then remove fuel filter (Fig. 6A6-27). 8. Disconnect fuel line at fuel pump. If A /C equipped, remove rear compressor brace. Remove fuel line. 9. Disconnect the fuel return line from the injection pump (Fig. 6A6-28). 10. Using two wrenches, disconnect injection pump lines at the nozzles. 20 FT. LBS. 11. Remove 3 nuts retaining injection pump, using tool J-26987. Fig. 6A6-27--Fuel Filter Lines LIGHT TRUCK SERVICE MANUAL 12. Remove pum p and cap all open lines and nozzles. V8 - DIESEL Installation 1. Position engine No. 1 cylinder. Align m ark on balancer with zero m ark on indicator. R efer to Figure 6A6-29 for position of injection pum p driven gear. (The index is offset to the right when num ber one is at T.D .C .). 2. Remove protective caps then line up offset tang on pum p driveshaft with the pum p driven gear and install pum p, fully seating pum p by hand. 3. In stall 3 nuts and lock w ashers retain in g injection pum p, do not tighten. Connect injection pump lines at nozzles, then tighten, using two wrenches. Torque to 25 lbs. ft. (34 N-m). 4. Connect fuel return lines to the injection pump (fig. 6A 6-28). 5. Align m ark on injection pum p with line on adapter and tighten nuts. Torque to 18 lbs. ft. (24N -m ) (Fig. 6A614). • Use a 3 /4 " open end wrench on the boss at the front of the injection pump to aid in rotating the pump to align the m arks. 6. A d ju st the th ro ttle rod (see L IN K A G E A D JU S T M E N T ). 7. In stall fuel line from fuel pum p to fuel filter. If equipped with A /C , install rear compressor brace. 8. Install bellcrank and hairpin clip. 9. Install throttle and T.V. cable or detent cable to intake manifold and attach to bellcrank. A djust T.V. or detent cable (see L IN K A G E A D JU S T M E N T ). 10. Connect throttle rod and retu rn spring. 11. S ta rt engine and check for fuel leaks. 12. Remove screened covers from intake manifold then install air crossover. 13. Install tubes in flow control valve in air crossover and ventilation filters in the valve covers. 14. Install air cleaner. 15. S ta rt engine and let run for one to two minutes. 16. T urn off engine for about two m inutes, then restart. (This lets air bleed off within the pump.) 6A 6-13 Replacement of Adapater (Fig. 6A6-30, 6A6-31) 1. R efer to "Injection Pum p and Lines" removal for pump assembly removal. 2. Remove the adapter to block bolts and remove the adapter. 3. Loosely install the adapter in the block. 4. R efer to "R ep la ce m en t of A d apter S e a l," steps 4 through 7. 5. R efer to "M a rk in g Injection P um p A d a p te r" for completion. Marking Injection Pump Adapter (Fig. 6A6-32) 1. File off the original m ark on the adpater. DO N O T file off the m ark on the pump. 2. Position engine on N o. 1 cylinder. A lign m ark on balancer with zero m ark on indicator. R efer to Fig. 6A6-29 for position of injection pump driven gear. (The index is offset to the right when num ber one is at T.D .C.). 3. Install T im ing Tool, J-26896, into pum p ad a p ter. Torque tool tow ard cylinder No. 1 to 50 ft. lbs. (68 N -m ). W hile holding torque, m ark injection pum p adapter. Remove tool. INJECTION PUMP ADAPTER, ADAPTER SEAL AND NEW ADAPTER TIMING MARK Replace of Adapter Seal (Fig. 6A6-30 and 6A5-31) 1. R efer to "Injection Pum p and Lines" removal for pum p assembly removal. 2. Using probe, pry out the adapter seal w ithout nicking the adapter. 3. Loosen the adapter to block bolts. 4. Lube the new seal with chassis lube on both the I.D. and O.D. of the seal. 5. Install the seal using tool J-28425. First install the seal on the tool, then install the seal into the adapter. (See Fig. 6A6-30). 6. Remove the tool and inspect to see if the seal is properly installed. 7. M ake sure the lower adapter to block bolt has a washer, then torque the adapter bolts to 39 N -m (25 ft. lbs.). 8. R efer to "M ark in g Injection P um p A d a p te r" for completion. Fig. 6A6-30--lnstalling Adapter Seal LIGHT TRUCK SERVICE MANUAL 6A 6-14 V8-D IE SE L VALVE COVER Removal 1. R efer to " IN J E C T IO N P U M P A N D L IN E S " for removal of lines. 2. Remove valve cover to cylinder head attaching screws. Remove accessory m ounting brackets as necessary and remove valve cover. Installation 1. Thoroughly clean the head and valve cover sealing surfaces. Apply # 1 0 5 2 2 8 9 RTV sealer (or equivalent) to the valve cover. (Fig. 6A6-33). 2. Install valve cover and screws so they are fully seated and not stripped. Install any m ounting brackets which were removed. (Fig. 6A 6-34). 3. Refer to "IN J E C T IO N P U M P A N D L IN E S " for installation of lines. INTAKE MANIFOLD Removal 1. Remove air cleaner assembly. LIGHT TRUCK SERVICE MANUAL 2. D rain radiator, then disconnect upper radiator hose and therm ostat bypass hose from w ater outlet. Also disconnect heater hose and vacuum hose from w ater control valve. 3. Rem ove b re ath er pipes from valve covers and air crossover. 4. Remove air crossover and cap intake manifold with J-26996-2 or J-26996-10 screened covers. 5. Disconnect throttle rod and return spring. If equipped with cruise control, remove servo. 6. Remove hairpin clip at bellcrank and disconnect cables, then remove throttle and T.V. or detent cables from bracket on the intake manifold and position cable away from engine. 7. Disconnect wiring as necessary. 8. Remove generator an d /o r air conditioning compressor brackets as necessary. 9. Disconnect fuel line from fuel pum p and fuel filter and remove fuel filter and bracket. 10. Disconnect lines at nozzles, using a backup wrench on the nozzles. Remove injection pum p and cap all open lines and fittings on injection pump, filter and nozzles. DO NOT BEND INJECTION P U M P LINES. V 8-D IE SE L 6A 6-15 11. Disconnect fuel return line from injection pump. 12. Disconnect vacuum lines a t vacuum pump and remove vacuum pump. INTAKE MANIFOLD RAIN TUBE DRAIN TUBE CLAMP 13. Remove drain tube. 14. R em ove in tak e m anifold bolts, then rem ove intake m anifold. Remove adap ter seal. 15. Remove injection pum p adapter. 16. C lean machined surfaces of cylinder head and intake manifold with a putty knife. Use care not to gouge or scratch machines surfaces. Installation 1. C oat both sides of gasket sealing surface th at seal the intake manifold to the head with # 1 0 5 0 8 0 5 sealer, or equivalent, and position intake manifold gasket. (Fig. 6A6-35). Fig. 6A6-37--lntake Manifold Drain Tube 2. Install end seals, m aking sure th a t ends are positioned under cylinder heads. 3. Position intake manifold on engine and connect th er­ m ostat bypass hose to w ater pump. ADAPTER SEAL ADAPTER LUBRICATE SEAL TOOL ADAPTER & MANIFOLD ''C ^ Fig. 6A6-38--lnstalling A dapter Seal VACUUM PUMP (OIL PUMP DRIVE) 20 FT. LBS: (27 N-m) " 0 " RING (APPLY LUBE TO 0 " RING BEFORE INSTALLING) NOTICE: DO NOT OPERATE ENGINE WITHOUT VACUUM PUMP AS THIS IS THE DRIVE FOR THE ENGINE OIL PUMP AND ENGINE DAMAGE WOULD OCCUR. Fig. 6A6-39--Drive V acuum Pum p 4. Dip intake manifold bolt in engine oil and torque in sequence shown to 15 lbs. ft. (20 N -m ). T hen re-torque to 40 lbs. ft. (54 N -m ) (Fig. 6A6-36). 5. Apply RTV sealer on the cone shaped surface of the drain tube and on the cham fered hole of the intake LIGHT TRUCK SERVICE MANUAL 6A 6-16 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. V8 - DIESEL manifold. Apply sealer to the threads of the drain tube clamp bolt, then install drain tube (Fig. 6A6-37). Apply chassis lube to seal area on adapter, taper edge and seal area in intake manifold. Apply chassis lube to I.D. and O.D. of adapter seal and to seal installing tool J-28425. Install seal on tool. Push seal on injection pum p adapter with tool J-28425 (fig. 6A6-38). Remove tool and inspect to see if properly positioned. Remove caps from injection pum p lines. Align offset tang on pum p drive shaft with offset in pum p driven gear then install injection pump. Connect injection pum p lines to nozzles. Align m ark on injection pump with m ark on adapter. Use a 3 /4 " open end wrench on the boss a t the front of the injection pum p to aid in rotating the pump to align the marks. Install fuel filter bracket and filter, then connect fuel lines. Connect the fuel return line to the injection pump. Install vacuum pum p and vacuum lines. (Fig. 6A6-39). NOTICE: Do not operate engine without vacuum pump assembly, as this is the drive for the engine oil pump, and engine damage may result. Connect wiring. Install an d /o r connect generator and air conditioning compressor brackets as necessary. Install cable in cable bracket and bellcrank, then install bellcrank to intake manifold. A djust the T.V. or detent cable (See " Linkage A d ju stm en t"). Connect throttle rod and return spring. S ta rt engine and check for fuel leaks. Remove screened covers from intake manifold. Install air crossover. Install breather tubes from valve cover filters and flow control valve at the air crossover. Connect upper rad iato r hose and heater hose. Connect vacuum hose to w ater control valve. Fill cooling system. ROCKER ARM ASSEMBLIES (Figs. 6A6-40&6A641) Removal 1. 2. 3. 4. Remove air cleaner and install screened cover. Remove high pressure fuel lines to nozzles. Remove valve cover. Remove rocker arm flanged bolts, pivots and rocker arm s. Remove each set (one set per cylinder) as a unit. Fig. 6A6-41--Removing Rocker Arms VALVE LIFTERS Roller hydraulic lifters are used to reduce the am ount of friction between the valve lifter and the cam shaft lobe. Guides keep the lifters from rotating on the cam shaft lobes. Installation 1. Position a set of rocker arm s (for one cylinder) in the proper location. R efer to "V alve Lifter Bleed Down" as lifters m ust be bled down as possible valve to piston interference, due to close tolerances, could exist. 2. Lubricate wear points with # 1 0 5 0 1 6 9 lubricant or equivalent and install the pivots. 3. Install the hardened flanged bolts and tighten alter­ nately. Torque bolts to 25 lbs. ft. (34 N-m). LIGHT TRUCK SERVICE MANUAL Operation Oil is supplied to the lifter through a hole in the side of the lifter body which indexes with a groove and hole in the lifter plunger. Oil is then m etered past the oil m etering valve in the lifter, through the push-rods to the rocker arm s. (Fig. 6A6-42). W hen the lifter begins to roll up the cam lobe, the check valve disc is held against its! seat in the plunger by the check V8-D IE SE L ENGINE VALVE CLOSED 6A 6-17 V IE W A ENGINE VALVE OPEN Fig. 6A6-44--Valve Lifter Guide and Retainer valve disc spring which traps the oil in the base of the lifter body below the plunger. The plunger and lifter body then raise as a unit, pushing up the push-rod to open the valve. The force of the valve spring which is exerted on the plunger through the rocker arm and push-rod causes a slight am ount of leakage between the plunger and lifter body. This "leakdow n" allows a slow escape of trapped oil in the base of the lifter body. As the lifter rides down the other side of the cam lobe and reaches the base circle or "valve closed" position, the plunger spring quickly moves the plunger back (up) to its original position. This movement causes the check valve disc to open against the check valve disc spring and oil from within the plunger is draw n into the base of the lifter. This restores the lifter to zero lash. The cylinder block will also be m arked if the oversize lifter is used. (Fig. 6A6-43). 1. Refer to " IN T A K E M A N IF O L D " for removal. 2. Remove valve covers, rocker arm assemblies and pushrods. 3. Remove valve lifter guide retainer bolts (Fig. 6A 6-44). 4. Remove the retainer guides and valve lifters. Disassembly 1. 2. 3. 4. Remove the retainer ring with a small screwdriver. Remove push-rod seat and oil m etering valve. Remove plunger and plunger spring. Remove check valve retain e r from plunger, then remove valve and spring. Removal Valve lifters and push-rods should be kept in order so they can be reinstalled in their original position. The push rods have a "w ing" at the upper end so the push rod can only be installed one way. This is necessary as the ball hardness is not the sam e on both ends. Some engines will have both standard and .010" oversize valve lifters. The .010" oversize lifter is etched " 0 " on the side of the lifter. Cleaning and Inspection A fter lifters are disassem bled, all p arts should be cleaned in clean solvent. A small particle of foreign m aterial under the check valve will cause m alfunctioning of the lifter. Close inspection should be made for nicks, burrs or scoring of parts. If either the roller body or plunger is defective, replace with a new lifter assembly. Fig. 6 A 6 -4 3 --O .S . Valve Lifter Identification LIGHT TRUCK SERVICE MANUAL 6A 6-18 V 8 - DIESEL W henever lifters are removed, check as follows: 1. Roller should rotate freely, but without excessive play. 2. Check for missing or broken needle bearing. 3. Roller should be free of pits or roughness. If present, check cam sh aft for sim ilar condition. If pits or roughness are evident, replace lifter and cam shaft. Assembly 1. C oat all lifter parts with a light coating of clean engine oil. 2. Assem ble valve disc spring and retainer into plunger. (Fig. 6A6-45). M ake sure retainer flange is pressed tight against bottom of recess in plunger. 3. Install plunger spring over check retainer. 4. Hold plunger with spring up and insert into lifter body. Hold plunger vertically to prevent cocking spring. 5. Install oil m etering valve and push rod seat into lifter and install retaining ring. VALVE LIFTER BLEED DOWN If the intake m anifold has been removed and if any rocker arm s have been loosened or removed; it will be necessary to remove those valve lifters, dissassemble, drain the engine oil then reassem ble the lifters. See "V A LV E L IF T E R D IS A S S E M B L Y ". If the intake m anifold has not been removed but rocker arm s have been loosened or removed, valve lifters can be bled down by the following procedure: 1. Before installing any removed rocker arm s, rotate the engine crankshaft to a position of No. 1 cylinder being 32° before top dead cen ter. T his is 13mm ( 1 /2 " ) beyond the end of the tim ing indicator. It may be necessary to remove No. 1 cylinder’s glow plug to determ ine if the position of the piston is the correct one. The compression pressure will tell you th a t you are in the right position. 2. 3. 4. 5. 6. 7. NOTICE: Use only hand wrenches to torque the rocker arm pivot bolt to avoid engine dam age. If removed, install the N o. 5 cylinder pivot and rocker arm s. Torque the bolts alternately between the intake and exhaust valves until the exhaust valve begins to open, then stop. Install rem aining rocker arm s but w atch No. 3 intake and N o. 8 intake valves (if these rocker arm s were removed) as the pivot bolts are being torque. Do not torque No. 3 and No. 8 intake valve pivots beyond the point th a t the valve would be fully open. This is indicated by strong resistance while still turning the pivot retaining bolts. Going beyond this would bend the push rod. T orque the bolts S L O W L Y allowing the lifter to bleed down. Finish torquing N o. 5 cylinder rocker arm pivot bolt SL O W L Y . Do not go beyond the point th a t the valve would be fully open. T his is in d icated by strong resistance while still turning the pivot retaining bolts. Going beyond this would bend the push rod. DO N O T turn the engine crankshaft for at least 45 minutes. Finish reassem bling the engine as the lifters are being bled. LIGHT TRUCK SERVICE MANUAL NOTICE: Do not rotate the engine until the valve lifters have been bled down, or dam age to the engine will occur. Valve Lifter Diagnosis 1. M om entarily Noisy W hen Vehicle Is Started: This condition is normal. Oil drains from the lifters which are holding the valves open when the engine is not running. It will take a few seconds for the lifters to fill after the engine is started. 2. In te rm itte n tly N oisy On Idle O nly, D isappearing W hen Engine Speed Is Increased: Interm ittent clicking may be an indication of a pitted check valve disc, or it may be caused by dirt. Correction: Clean the lifter and inspect. If check valve disc is defective, replace lifter. 3. Noisy A t Slow Idle O r W ith H ot Oil, Q uiet W ith Cold Oil O r As Engine Speed Is Increased: Leak check the suspected lifters and replace any lifters th at do not meet specifications. 4. Noisy A t High C ar Speeds A nd Q uiet A t Low Speeds: a. High oil level-Oil level above the " F u ll" m ark allows crankshaft counterw eights to churn the oil into foam. W hen foam is pumped into the lifters, they will become noisy since a solid colum n of oil is required for proper operation. Correction: D rain oil until proper level is obtained. See P E R IO D IC M A IN T E N A N C E Section. b. Low oil level - Oil level below the "A d d " m ark allows air to the pump at high speeds which results in noisy lifters. Correction: Fill until proper oil level is obtained. See P E R IO D IC M A IN T E N A N C E Section. c. Oil pan bent on bottom or pump screen cocked, replace or repair as necessary. 5. Noisy A t Idle Becoming Louder As Engine Speed Is Increased To 1500 rpm: This noise is not connected with lifter m alfunction. It becomes most noticeable in the vehicle at 10 to 15 mph (16 to 24 k m /h ) " L " range, or 30 to 35 mph (48 to 56 km /h) "D " range and is best described as a hashy sound. A t slow idle, it may be entirely gone or appear as Fig. 6A6-46--C hecking Valve Spring V 8 - DIESEL a light ticking noise in one or more valves. It is caused by one or m ore of the following: a. Badly worn or scuffed valve tip and rocker arm pad. b. Excessive valve stem to guide clearance. 6 A 6-19 possible valve to piston in terference, due to close tolerances, could exist. 2. Install lifters and push-rods into original position in cylinder block. See note under Removal. c. Excessive valve seat runout. 3. Install manifold gaskets and manifold. d. Off square valve spring. e. Excessive valve face runout. 4. Position rocker arm s, pivots and bolts on cylinder head as shown in Fig. 6A6-40. f. Valve spring dam per clicking on rotator. 5. Install valve covers. To check valve spring and valve guide clearance, remove the valve covers: a. Occasionally this noise can be elim inated by rotating the valve spring and valve. C rank engine until noisy valve is off its seat. R otate spring. This will also rotate valve. R epeat until valve becomes quiet. If correction is obtained, check for an off square valve spring. If spring is off square m ore th an 1 /1 6 " (1.6m m ) in free position, replace spring. (Fig. 6A646). b. C heck for excessive valve stem to guide clearance. If necessary, correct as required. 6. Valves N oisy R egardless O f E ngine Speed: This condition can be caused by foreign particles or exces­ sive valve lash. Check for valve lash by turning engine so the piston in th a t cylinder is on top dead center of firing stroke. If valve lash is present, the push-rod can be freely moved up and down a certain am ount with rocker arm held against valve. If OK, clean suspected valve lifters. Valve lash indicates one of the following: 6. Install intake m anifold assembly. GLOW PLUG A burned out FA ST G LO W glow plug tip may bulge then break off and drop into the pre-cham ber when the glow plug is removed. W hen this occurs, the cylinder head must be removed and the pre-cham ber removed from the head to remove the broken tip. DIESEL INJECTION NOZZLE TESTING W hen a m alfunction occurs where the injection nozzles are suspected as the cause, they may be tested as follows: a. W orn push-rod. b. W orn rocker arm . c. L ifter plunger stuck in down position due to dirt or carbon. d. Defective lifter. Checking of the above four items: 1. Look at the upper end of push-rod. Excessive wear of the spherical surface indicates one of the following conditions. a. Im proper hardness of the push-rod ball. T he pushrod and rocker arm m ust be replaced. b. Im proper lubrication of the push-rod. The push-rod and rocker arm m ust be replaced. The oiling system to the push-rod should be checked. 2. If push-rod appears in good condition and has been properly lubricated, replace rocker arm and recheck valve lash. 3. If valve lash exists and push-rod and rocker arm are okay, trouble is in the lifter. L ifter should be replaced. Installation C oat the roller and bearings of lifter with # 1052365 lubricant or equivalent. P rim e new lifters by w orking lifter plunger while subm erged in new kerosene or diesel fuel. Lifter could be dam aged if dry when starting engine 1. W hen a rocker arm is loosened or removed, valve lifter bleed down is required. R efer to "V A L V E L IF T E R B L E E D D O W N ". L ifters m ust be bled down as LIGHT TRUCK SERVICE MANUAL 6A 6-20 V 8 - DIESEL Test Preparation To ensure correct preparation of the nozzle for testing, the following procedure should be performed. 1. Clean the carbon from the tip of the nozzles with a brass wire brush. Do not use motorzed brush or a steel wire brush as they could dam age the nozzle tip. Diesel fuel should never be used as a test fluid. It is recom m ended th at SA E J967D or equivalent be used. M ake sure th at the tester reservoir has a sufficient am ount of fluid to complete test. A t this point the proper connecting adapter to be used from th e nozzle to the te ste r should be selected (adapters are available from the tester m anufacturer). Connect the nozzle to the tester (available tool) with the tip pointing down. Testing Procedure 12 FT. LBS. (16 N-m) 25 FT. LBS. (34 N-m) NOZZLE (TORQUE MUST BE APPLIED TO LARGEST NOZZLE HEX) Fig. 6A6-48a~lnjection Nozzle Installation Injection Nozzle Removal (With Lines Removed) Roosa-Master Removal 1. Remove the fuel retu rn line clam ps from all nozzles on the bank where a nozzle is to be removed then remove th a t fuel return line. 2. Remove nozzle spring clam p and spacer; then remove nozzle using tool J-29082. 3. Cap the nozzle inlet line and the tip of the nozzle. Installation 1. If a nozzle is to be reinstalled after removal, a new compression seal and carbon stop seal m ust be installed after removal of the used seals. See Figure 6A6-47 for seal installation. 2. Remove protective caps then install injection nozzle and spring clam p and spacer. T orque bolt to 25 lb. ft. (34 N -m ) (Fig. 6A 6-48). 3. Install fuel return line. 4. Start engine and check for leaks. LIGHT TRUCK SERVICE MANUAL CAUTION:When testing nozzles, do not place your hands or arms near the tip of the nozzle. The high pressure atomized fuel spray from a nozzle has sufficient penetrating power to puncture flesh and may result in blood poisonging and/or damaged tissue. The nozzle tip should always be enclosed in a receptacle, preferably transparent, to contain the spray. To test the perform ance of the nozzle, the following items should be checked as described. 1. Opening pressure test Close the pressure gage valve and flush the nozzle by operating the test pump rapidly. Open the gage valve and raise the pressure slowly until the nozzle opens. (The gage reading will drop sharply at this point.) The nozzle opening pressure will be the m axim um gage pressure observed and should be within the following limit: 1750 PSI to 1900 PSI. 2. Spray pattern test Close the pressure gage valve. O perate the tester at approxim ately 30 strokes per m inute (one strke every two seconds) and observe spray pattern. CAUTION:Test fuel spray is flam mable. Keep vapor aw ay from open flames or personal injury could result. When testing nozzles, do not place your hands or arms near the tip of the nozzle. The high pressure atomized fuel spray from a nozzle has sufficient penetrating power to puncture flesh and destroy tissue and may result in blood poisoning. The nozzle tip should always be enclosed in a recepta­ cle, preferably transparent, to contain the spray. The nozzle should have a finely atom ized cloud-like pattern. The pattern should not be streaky with tester fluid. Refer to Figure 6A6-49. 3. Seat tightness test W ith the nozzle top pointed downward and the gage valve closed, operate the tester rapidly to firmly seat the valve. Dry the nozzle tip thoroughly. Open the gage valve and raise the pressure to 1300-1400 P S I/ W hile holding this pressure, a drop of tester fluid should not form on the tip within ten seconds. Slight dam pness, however, is perm issable with a used nozzle. V8-D IE SE L 4. C h atter Test W ith gage valve closed, the nozzle should ch atter when the tester is operated rapidly. C h atter is rapid opening and closing of the nozzle valve while fuel is being pumped through the nozzle. This checks the nozzle under extrem e load conditions. C h atter should be audible and can also be felt in the handle of the tester. C h atter does not occur in the engine. It is an indication of valve freedom. C h atter action is generally also an indication of proper seat width and interference angle. 5. R eturn Fuel Test Loosen connector nuts and reposition nozzle tip slightly above horizontal plane, as shown in Figure 6A6-49. R e-tighten connector nuts and raise pressure to 1500 PSI. N ozzle should not open. Observe fluid from nozzle return. A fter the first drop forms on return fuel end of nozzle, there should be 3 to 10 more drops in 30 seconds while m aintaining 1500 O SI. If a nozzle fails to m eet any of th e specifications described in the five tests above, it should be serviced by R oosa-M aster. 6A6-21 Injection Nozzle Removal (With Lines Removed) Lucas/D.E.D. Removal W hen lines are removed use back-up wrench on upper injection nozzle hex. 1. Remove nozzle by applying torque to the largest nozzle hex (Fig. 6A 6-47a). NOTICE: Always cap the nozzle and lines to prevent dam age or contam ination. 2. Remove copper nozzle gasket from the cylinder head if the gasket did not rem ain on the nozzle. Cleaning Inspection and Testing The most im portant checks on nozzles are seat tig h t­ ness and opening pressure. W hen a nozzle passes these tests, the spray pattern with the nozzle in the engine is nearly always satisfactory. 1. Check the torque of the inlet fitting to nozzle body (Fig. 6A6-47). 2. Clean the carbon from the tip of the nozzle with a soft brass wire brush. 3. Assemble nozzle to tester. a. Use SA E J967D calibrating oil at room tem perature, approxim ately 70°F (20°C). CAUTION:Do not use diesel fuel. Diesel fuel is unstable with respect to corrosion inhibition and may cause skin problems. b. Use a connecting line from the nozzle to the tester 12" long by 1 /4 " O .D .b y 1/16" I.D. c. Refer to the equipm ent m anufacturers instructions for exact test procedures. 4. T E ST S P E C IF IC A T IO N S a. O P E N IN G P R E S S U R E - The pressure control valve should be slightly opened and the handle of the test equipm ent operated at a slow rate (between three and six seconds for one full stroke) to deter­ mine the actual opening pressure of the nozzle. The minimum opening pressure is 870 P.S.I. (6000 kPa). b. SPR A Y P A T T E R N NOTICE: Close the pressure gage for this test or the gage could be dam aged. CAUTION:Test fuel spray is fam m able. Keep vapor away from open flames or personal injury could result. CAUTION:When testing nozzles, do not place your hands or arms near the tip of the nozzle. The high pressure atomized fuel spray from a nozzle has sufficient penetrating power to puncture flesh and destroy tissue and may result in blood poisoning. The nozzle tip should always be enclosed in a receptacle, preferably transparent, to contain the spray. Fig. 6 A 6 -4 9 --N o zzle Testing 1. O perate the handle of the test equipm ent at a rate of thirty strokes per m inute. 2. The spray pattern should be atom ized near the tip. Any solid column of fuel or small droplets forming near the tip m ake the pattern unacceptable. LIGHT TRUCK SERVICE MANUAL 6A 6-22 V 8 - DIESEL c. SE A T T IG H T N E S S -- Slightly open the pressure gage for this test the line pressure should first be allow ed to fall to a t least 290 P S I (2000 kP a) B ELO W the actual opening pressure (Step 4a). Dry the nozzle tip then increase the line pressure to 218 PSI (1500 kPa) B ELO W the actual opening pres­ sure (S tep 4 a). M a in ta in this p ressure for five seconds. A fter 5 seconds, patterns 1, 2 and 3 are acceptable, patterns 4 and 5 are not acceptable (Fig. 6A 6-49a). CYLINDER HEAD AND GASKET Removal 1. Rem ove intake m anifold. See " IN T A K E M A N I­ FO LD " for removal. 2. Remove valve cover. Loosen or remove any accessory brackets which interfere. 3. Disconnect glow plug wiring. 4. Remove ground strap from right cylinder head. Installation (Fig. 48a) 1. Remove protective caps from nozzle (If installed after testing). 2. M ake sure copper nozzle gasket is installed on the nozzle. 3. Install the nozzle and torque to 25 ft. lbs. (34 N-m ). Torque m ust be applied to the largest nozzle hex. 4. A ttach the lines using a back-up wrench on the upper injection nozzle hex. T orque the line nut to 25 ft. lbs. (34 N-m ). 5. Remove rocker arm bolts, pivots, rocker arm s and push rods. Scribe pivots and keep rocker arm s separated so they can be installed in their original locations. 6. Disconnect the exhaust m anifold from the head. Leave attached to the crossover pipe. 7. Remove engine block drain plug, from side of the block where head is being removed. 8. Remove cylinder head bolts and remove cylinder head. ^ If necessary to remove pre-cham ber, remove the glow plug and injection nozzle, then tap out with a small blunt drift. SEAT TIGHTNESS CHECK Fig. 6 A 6 -5 T -C y lin d e r H ead LIGHT TRUCK SERVICE MANUAL Gasket V 8 - DIESEL Fig. 6A6-54--Valve Location Fig. 6A6-52--Cylinder Head Torque Sequence Installation VALVES AND SPRINGS WITH HEAD REMOVED H ead gaskets are a special composition gasket th at m ust be used W IT H O U T a sealer. N o additional sealer can be used when installing the head gaskets as the passage surfaces are sealed when the gaskets are made, using a newly developed method and m aterial. This sealer is accurately printed on the surface of the gasket in the exact q u antity required and provides the desired bond between the head and the block. Applying additional sealer would only result in the possibility of leakage. 1. Install pre-cham ber, if removed. The pre-cham ber can only be installed in one position. (Fig. 6A6-50). 2. U se a 1 -1 /4 " socket to rein stall p re-ch am b er and install in cylinder head. 3. Install glow plug. The pre-cham ber should be flush ± .003 " to the face of the head. 4. Clean cylinder head bolts and dip in engine oil, torque bolts to 100 lbs. ft. (136 N -m ) in sequence shown, then re-torque in sequence to 130 lbs. ft.(176 N-m ). (Figs. 6A6-51 & 6A6-52). T orque head bolts before installing rocker arm s and pivots. Install the coolant drain plug. Bleed valve lifters. See "V alve L ifter Bleed D ow n." • •. n s s fo VALVE FACE ANGLE VALVE SEAT ANGLE VALVE SEAT I NSERT I NTAKE 1.875” (5. 7L) 44° 45° NO YES EXHAUST 1.625 (5. 7L) 30° 31 ° NO NO I NDUCTI ON HARDENED VALVE SEAT Fig. 6 A 6 -5 3 --V a lve Train Inform ation Chart t? 1. Remove valve keys by compressing valve spring with a tool such as J-5892-1. 2. Remove valve spring rotators or retainers and springs. 3. Remove oil seals from valve stems. 4. Remove valves. Keep valves separated so they can be installed in their original locations. (Fig. 6A 6-54). VALVE SEAL IDENTIFICATION Intake STD . - .005 " O.S. (G ray Colored) .010" - .013" O.S. (O range Colored) Exhaust STD. - .005" O.S. (Ivory Colored) .010" - .013" O.S. (Blue Colored) Installation 1. Install valves in their respective guides. 2. Install new oil seals over valve stem. .(nfi'iBO HEAD DI AMETER bn'R -..'s?!/- • Removal V A L V E T RA IN IN F O R M A T IO N TYPE 6A 6-23 3. 4. 5. 6. Position seals dow n as far as possible on valve stem . The seals will correctly position them selves w hen the engine is started. Position valve springs over valve stems. Install valve rotators then compress springs with a tool such as J-5892-1 and install valve stem keys. C heck valve springs and keys to be sure they are properly seated. Install exhaust manifold. Torque bolts and nuts to 25 ft. lbs. (34 N -m ). Bend exhaust m anifold bolt lock tabs. LIGHT TRUCK SERVICE MANUAL 6A 6-24 V 8 - DIESEL T ~ V IN T A K E V A L V E FACE A N G LE IN T A K E V A L V E SEAT A N G LE E XH AUST V A L V E FACE A N G LE EXH AUST V A L V E SEAT A N G LE Fig. 6A6-55--Relation of Valve S eat Angles Fig. 6A6-57--Measuring Rotator Height Reconditioning Measuring Valve Stem Height W hen reconditioning valves and valve seats, clean carbon from cylinder heads and valves using care not to gouge or scratch m achined surfaces. A soft wire brush is suitable for this purpose. W henever valves are replaced or new valves installed, the valve seats m ust be reconditioned. (Fig. 6A6-55). N arrow the valve seats to the specified width. This operation is done by grinding the portside with a 30° stone to lower the seat and a 60° stone to raise the seat. Intake valve seats are induction hardened and m ust be ground, not cut. If valve guide bores are worn excessively, they can be ream ed oversize. This will require replacem ent of the valves with oversize valves (stem s). The guide bores should be ream ed before grinding the valve seats. Valve clearance in guide bore should be .0015 " to .0032 " (exhaust) or .001" to .0027 " for the intake valve. W henever a new valve is installed, or after grinding valves, it will be necessary to m easure valve stem height as follows: .015" M IN IM U M BETWEEN VALVE STEM AND GAGE Install gage J-25289 as shown in Fig. 6A6-56. T here should be at least .015" (.38m m ) clearance on all valves between gage surface and end of valve stem. (Valve stem can be gaged with or w ithout the valve rotator on the valve.) If clearance is less than .015" (.38m m ), remove valve and grind tip of valve stems as required on a valve refacing m achine, using the "V ee" block attachm ent to insure a smooth 90° end. Also be certain to break sharp edge on ground valve tip. Observe an original valve to determ ine cham fer. A fter all valve keys have been installed on valves, tap each valve stem end with a m allet to seat valve rotators and keys. Using gage J-25289 as shown in Figs. 6A6-56 and 6A6-57, regage all valves between valve stem and gage .015" (.38m m ) m inim um and valve ro ta to r and gage .030" (.76m m ) m inim um . If any valve stem end is less than .005 " (. 12mm) above rotator, the valve is too short and a new valve m ust be installed. EX A M PLE: Valve R otator to G age C learance-.038 " (.97m m ) M inus Valve Stem to G age C learance-.035" (.89mm) -.003" (.08m m ). This is less than .005" (.12m m ) and new valve should be installed. T here m ust be a m inim um of .030" (.76m m ) clearance between valve rotator and gage. Failure to m aintain this clearance will cause rocker arm and valve ro ta to r interference. VALVE GUIDE BORE .015" GAGE INCLUDED IN CA RBURETOR K IT If the valve guide bores are worn excessively, they can be ream ed oversize. The following ream ers are available: J-5830-1 ........... 003" (.08m m ) Oversize Valve G uide R eam er Fig. 6A 6-56--M easuring Valve Stem Height LIGHT TRU CK SERVICE MANUAL J-6621 ............. 005" (.12m m ) Oversize Valve Guide Ream er V8 - DIESEL 6A 6-25 J5830-7 ............013" (.33m m ) Oversize Valve Guide Ream er If a standard or .003" O.S. valve guide bore is being ream ed, use the .003" oversize ream er. For the .005" oversize valve guide bore, use the .005 " oversize ream er; use the .013" ream er for the .010" or .013" O.S. valve guide bore. If too large a ream er is used and the spiraling is removed, the valve may not receive the proper lubrication. Occasionally a valve guide bore will be oversize as m anufactured. These are m arked on the inboard side of the cylinder heads on the m achined surface ju st above the intake manifold surface. (Fig. 6A6-58). These m arkings are visible w ithout removing any parts other than the air cleaner assembly. Before removing the cylinder heads to perform service to either the valves or valve guide bores, the cylinder heads should be inspected to determ ine if these m arkings are present. If no m arkings are present, the guide bores are stan d ard . If oversize m arkings are present, any valve replacem ent will require an oversize valve. If the oversize m arking is present, only th a t p a rtic u la r bore would be oversize, not all bores in th at cylinder head. Service valves are available in five different stem diam eters: Standard, .003" oversize, .005" oversize, .010" oversize, and .013" oversize. Reaming Before attem pting to ream the valve guide bores they should be cleaned using Tool J-8101 as shown in Fig. 6A659. This procedure to ream valve guide bores is shown in Fig. 6A6-60. Use care to hold ream er straight in valve guide bore. VALVE SPRING (HEAD ON ENGINE) To replace a worn or broken valve spring w ithout removing the cylinder head proceed as follows: Removal 1. Remove rocker arm assemblies. 2. R otate engine so piston is at top dead center for each cylinder. 3. Install Tool J-5892-1 (Fig. 6A6-61) and compress the valve spring until valve keys are accessible; then remove keys, valve rotators and springs. If valve spring does not compress, tap tool with a m allet to break bind at rotator and keys. Checking Rotators T he ro tato rs cannot be disassem bled and require replacem ent only when they fail to rotate the valve. R otator action can be checked by applying a daub of paint across the top of the body and down the collar. Run engine approxim ately 1500 rpm. There should appear to be motion between the body and collar; the body will appear to "w alk" around the collar. R otator action can be either clockwise or counterclockwise. Sometimes on removal and LIGHT TRUCK SERVICE MANUAL 6A 6-26 V8 - DIESEL 6. 7. 8. 9. Disconnect exhaust and crossover pipes. Remove oil cooler lines at filter base. Remove starter assembly. Remove engine mounts from engine block, then jack front of engine up. 10. Remove oil pan attaching bolts and remove oil pan. Installation (Fig. 6A6-63) 1. Apply # 1 0 5 0 8 0 5 sealer or equivalent to both sides of pan gaskets and install on block. 2. Install front and rear seals (rubber). 3. W ipe lube, # 1050169 or equivalent, on seal area and install pan. Torque bolts to 10 lbs. ft. (14N-m ). Reverse the removal procedure. Fill crankcase as explained in the P E R IO D IC M A IN T E N A N C E Section. OIL PUMP Removal 1. Remove oil pan. 2. Remove the oil pum p to rear main bearing cap a tta c h ­ ing bolts, then remove pum p and drive shaft extension. reinstallation, the direction of rotation will change but this does not m atter so long at it rotates. Any tim e the valves are removed for service the tips should be inspected for im proper p a tte rn w hich could indicate valve ro tato r m alfunction. (Fig. 6A6-62). Installation 1. Install valve spring and rotator. Using Tool J-5892-1, compress the valve spring until the valve keys can be installed. 2. Install rocker arm assemblies. 3. Bleed valve lifters w here rocker arm pivots were loosened. R efer to "V A L V E L IF T E R B L E E D D O W N ". OIL PAN Removal 1. Remove oil pum p drive and vacuum pump. 2. Disconnect b attery cables. Remove dipstick. 3. Remove upper radiato support and fan shroud a ttac h ­ ing screws. 4. H oist the car and drain oil. 5. Remove flywheel cover. LIGHT TRUCK SERVICE MANUAL V 8 - DIESEL Disassembly (Fig. 6A6-64) 1. Remove the oil pump drive shaft extension. 2. Position thum b over pressure regulator bore before removing cotter pin, as the spring is under pressure. Then remove the cotter pin, spring and the pressure regulator valve. 3. R em ove th e oil pum p cover a tta c h in g screws and remove the oil pump cover and gasket. 4. Remove the drive gear and idler gear from the pump body. Inspection Check the gears for scoring or other dam age. If they are dam aged, new gears should be installed. D uring assem ­ bly, the gear end clearance should be gaged. Proper end clearance is .0005" to .0075". Also check the pressure regulator valve, valve spring and bore for dam age. Proper valve to bore clearance is .0025 " to .0050". The checking of gear end clearance will be covered in "A ssem bly". Check the extension shaft at each end for abnorm al wear. The shaft is h ard en ed a t both ends and identified by a red dye m arking. Assembly 1. Install the gears and shaft in the oil pump body and check the gear end clearance by placing a straight edge over the gears and m easure the clearance between the straight edge and the gasket surface. The clearance should be betw een .0 0 0 5 " to .0 0 7 5 ". If the end clearance is to the high lim it, check for scores in the cover th a t would bring the total clearance over the specified am ount. 2. Install the cover screws and tighten alternately and evenly. The torque is 8 lbs. ft. (1 lN -m ). 3. Position the pressure regulator valve into the pump cover, closed end first, then install th e spring and retaining pin. 4. Assemble the drive shaft extension to the drive shaft. 6A 6-2 7 Installation 1. Insert the drive shaft extension through the opening in the main bearing cap and block until the shaft m ates into the vacuum pum p driven gear. 2. Position pum p onto the rear main bearing cap and install attaching bolts. Torque bolts to 35 lb. ft. (47 N-m) (Fig. 6A 6-65). 3. Install the oil pan. R efer to O IL PAN Installation. CONNECTING ROD AND PISTON Removal 1. Remove intake m anifold, head or heads. 2. Remove oil pan. 3. Remove oil pum p assembly. 4. S tam p cylinder num ber on the m achined surfaces of the bolt bosses of the connecting rod and cap for identification when reinstalling. If the pistons are to be rem oved from the connecting rod, m ark cylinder num ber on piston with a silver pencil or quick drying paint for proper cylinder identification and cap to rod location. The right bank is num bered 2-4-6-8, left bank 1-6-5-7. 5. Exam ine the cylinder bore above ring travel. If ridge exists, remove ridge with ridge ream er before a ttem p t­ ing to remove the piston and rod assembly. 6. Remove rod bearing cap and bearing. 7. Install guide hose over threads of rod bolts. This to prevent dam age to bearing jo u rn al and rod bolt threads. (Fig. 6A 6-66). 8. Remove rod and piston assembly through the top of the cylinder bore. 9. Remove other rod and piston assemblies in the same m anner. ROD BEARINGS The connecting rod bearings are designed to have a slight projection above the rod and cap faces to insure a positive contact. Fig. 6A 6-66~C o nn ecting Rod Bolt G uide LIGHT TRUCK SERVICE MANUAL 6A 6-28 V8 - DIESEL C onnecting rod b earings can be replaced w ithout removing the rod and piston assembly from the engine. 1. Remove oil pan. • It m ay be necessary to remove oil pum p to provide access to rear connecting rod bearings. 2. W ith crankpin at the bottom , stam p cylinder num ber on m achined surfaces of connecting rod and cap for identification when reinstalling, then remove caps. 3. Inspect cran k p in s for roughness and w ear. S light roughness m ay be removed with a fine grit polishing cloth satu rated with engine oil. Burrs m ay be removed with a fine oil stone by moving the stone on the crankpin circum ference. Do not move the stone back and forth across the crankpin. If the crankpins are scored or ridged, the crankshaft m ust be replaced. 4. T he crankpins should be checked for out-of-round and correct size with a m icrom eter. M axim um out-of-round m ust not exceed .0015". • C rankpins will norm ally be standard size. If any undersized crankshafts are used, all will be .010" U.S. and an .010" will be stam ped on the num ber six counterw eight. LIGHT TRUCK SERVICE MANUAL 5. Clean oil from crankpin bearing cap, connecting rod and outer and inner surface of bearing inserts. Position insert so th a t tang is properly aligned with notch in rod and cap. (Fig. 6A6-67). 6. Place a piece of plastic gaging m aterial in the center of lower bearing shell. 7. Remove bearing cap and determ ine bearing clearances by com paring the width of the flattened plastic gaging m aterial at its widest point with the graduation on the container. The num ber w ithin the graduation on the envelope indicates the clearance in thousandths of an inch. If this clearance is g reater than .0035", replace the bearing and recheck clearance with plastic gaging m aterial. L u b ricate bearing w ith engine oil before installation. R epeat Steps 2 through 8 on rem aining connecting rod bearings. All rods m ust be connected to their crankpins when rotating the crankshaft to prevent engine dam age. Bearings are identified as shown in Fig. 6A6-68. 8. M easure the rod side clearance as shown in Fig. 6A669. Clearance should be .006 " to .020 ". ROD ASSEMBLY If a rod is twisted or bent, a new rod m ust be installed. NO ATTEM PT SH O U LD BE MADE TO S T R A IG H T E N C O N N E C T IN G RO D S. PISTON (Fig. 6A6-70) Measuring Piston Piston Selection 1. Check used piston to cylinder bore clearance as follows: V 8 - DIESEL 6A 6-29 4. Select new piston and m ark piston to identify the cylinder for which it was fitted. (On some cars, oversize pistons may be found. These pistons will be .010" oversize). Honing 1. W hen cylinders are being honed, follow the m anufac­ tu re r’s recom m endations for the use of the hone. 2. Occasionally during the honing operation, the cylinder bore should be thoroughly cleaned and the selected piston checked for correct fit. 3. W hen finish honing a cylinder bore, the hone should be moved up and down at a sufficient speed to obtain very fine uniform surface finish m arks in a cross hatch pattern of approxim ately 45 to 65 degrees included angle. The finish m arks should be clean but not sharp, free from imbedded particles and torn or folded metal. 4. Perm anently m ark the piston for the cylinder to which it has been fitted and proceed to hone the rem aining cylinders. NOTICE: H andle pistons with care. Do not attem pt to force pistons through cylinders until the cylinders have been honed to correct size. Pistons can be distorted through careless handling. 5. Thoroughly clean the bores with hot w ater and deter­ gent. Scrub well with a stiff bristle brush and rinse thoroughly with hot w ater. It is extrem ely essential that a good cleaning operation be performed. If any of the abrasive m aterial is allowed to remain in the cylinder bores, it will rapidly wear the new rings and cylinder bores. The bores should be swabbed several tim es with light engine oil and a clean cloth and then wiped with a clean dry cloth. C Y L IN D E R S S H O U L D N O T BE C L E A N E D W IT H K E R O S E N E O R G A S O L IN E . Clean the rem ainder of the cylinder block to remove the excess m aterial spread during the honing operation. Checking Cylinder Bore a. M easure the cylinder bore diam eter with a telescope gage. b. M easure the piston diam eter (Fig. 6A 6-71). W hen m easuring piston fo size or taper, m easurem ent must be m ade as shown with the piston pin removed. c. S ubstract piston diam eter from cylinder bore diam e­ ter to determ ine piston-to-bore clearance. d. C om pare piston-to-bore clearan ce o b tain ted with those clearances recom m ended (.005" to .006"). D eterm ine if piston-to-bore clearance is in accepta­ ble range. e. W hen m easuring taper, the largest reading m ust be at the bottom of the skirt. Allowable taper is .000" to .002 ". 2. If used piston is not acceptable, check service piston sizes and determ ine if a new piston can be selected. (Service pistons are available in standard, high lim it and standard .010" over size). 3. If cylinder bore m ust be reconditioned, m easure new piston diam eter (Fig. 6A 6-71) then hone cylinder bore to obtain preferable clearance. Cylinder bore size can be m easured with inside m i­ crom eters or a cylinder gage. M axim um allowable taper of the cylinder bore is .001". The most wear will occur at the top of the ring travel. Reconditioned cylinder bores should be held to not more than .001" out-of-round and .001" taper. If the cylinder bores are smooth, the cylinder walls should not be deglazed. If the cylinder walls are scored, the walls m ay have to be honed before installing new rings. It is im portant th at reconditioned cylinder bores be thoroughly washed with a soap and w ater solution to remove all traces of abrasive m aterial to elim nate prem ature wear. Cleaning Piston Clean the pistons by scraping carbon off the top of the piston. Deposits in the ring grooves should be removed with a suitable ring groove cleaning tool. It is im portant th at the ring grooves be completely free of deposits. Rings (Fig. 6A6-72) The pistons have three rings (two compression rings and one oil ring). The oil ring consists of two rails and an expander. LIGHT TRUCK SERVICE MANUAL 6A 6-30 V8 - DIESEL See Piston Ring C learance C h a rt Fig. 6A6-75. Side Clearance Each ring m ust be checked for side clearance in its respective piston groove by inserting a feeler gage between the ring and its upper land. (Fig. 6A6-74). The piston grooves m ust be cleaned before checking ring for side clearance. See Piston Ring C learance C hart. To check oil ring side clearance, the oil rings m ust be installed on the piston. Ring Installation For service ring specifications and detailed installation instructions, refer to the instructions furnished with the parts package. ROD AND PISTON Installation 1. Install connecting rod bolt guide hose over rod bolt threads. (Fig. 6A6-76). Pistons do not have oil drain holes behind rings. Ring Tolerances W hen installing new rings, ring gap and side clearance should be checked as follows: Piston Ring and Rail Gap Each ring and rail gap m ust be m easured with the ring or rail positioned squarely and at the bottom of the ringtravel area of the bore. (Fig. 6A6-73). FEELER GAUGE MEASURE RING GAP CLEARANCE WITH RING POSITIONED AT BOTTOM RING TRAVEL AS SHOWN Fig. 6A 6-73--M easuring Piston Ring G a p LIGHT TRUCK SERVICE MANUAL PISTON RING CLEARANCE CHART END GAP** Top Comp. Ring 2nd Comp. Ring Oil Ring Rails .015"-. 025" .015"-. 025" .015"-. 055" SIDE CLEARANCE* Top Comp. Ring 2nd Comp. Ring .004"-. 006" .0018"-. 0038" ** Refer to Fig. 6A5-73 * Refer to Fig. 6A5-74 Fig. 6A6-75--Piston Ring Clearance Chart V8 - DIESEL 6A6-31 PISTON AND CONNECTING ROD. INSTALL IN CYLINDER BORES #5, % , #7 & #8 Fig. 6A6-76--Connecting Rod Bolt Guide CONNECTING ROD BEARING CONNECTING ROD CAP / PISTON AND CONNECTING ROD. INSTALL IN CYLINDER BORES #1. #2, #3 & #4 Fig. 6A6-78--Piston Locations in Block Fig. 6A6-77--Piston Ring Compressor 2. Apply engine oil to rings and piston, then install piston ring compressing tool on piston. (Fig. 6A6-77). 3. Install each piston and rod in its respective cylinder bore so valve depression in top of piston is towards the inner side of engine. (Fig. 6A 6-78). • On the forw ard half of the engine, cylinders 1, 2, 3 and 4, the large valve depression goes to the front. • O n the rear h alf of the engine, cylinders 5, 6, 7 and 8, the large valve depression goes to the rear of engine. 4. L u b ric a te th e cran k p in w ith engine oil and install connecting rod bearing and cap, with bearing index tang in rod and cap on sam e side. W hen m ore than one rod and piston is being installed, the connecting rod cap a tta c h in g nuts should only be tightened enough to keep each rod in position until all have been installed. This will facilitate installation of rem aining piston assemblies. T he cle a ra n ce betw een th e a d ja c e n t rods, when checked with a feeler gage on each crankpin, should be from .006" to .020 " .(F ig . 6A6-79). Fig. 6A6-79--Connecting Rod Side Clearance PISTON PINS The piston pin is free floating and the correct fit in the piston is .0003 " to .0005 " and rod is .0003 " to .0013 " loose. If the pin to piston clearance is to the high lim it (.0005" piston or .0013" rod)., the pin can be inserted in the piston or rod with very little hand pressure and will fall through the piston or rod by its own weight. If the clearance is .0003", 5. Torque rod bolt nuts to 42 lbs. ft. (57 N-m ). LIGHT TRUCK SERVICE MANUAL 6A 6-32 V8 - DIESEL the pin will not fall through. It is im portant th a t the piston and rod pin hole be clean and free of oil when checking pin fit. The rod may be installed in the piston with either side facing up. W henever the replacem ent of a piston pin is necessary, remove the snap ring retaining the pin. Then remove the pin. It is very im portant th a t after installing the piston pin retaining snap rings th at the rings be rotated to make sure they are fully seated in their grooves. CRANKSHAFT PULLEY Removal 1. Remove belt(s). 2. Hoist vehicle. 3. Remove pulley bolts and pulley. Installation 1. Install pulley, and bolts. Torque to 20 lbs. ft. (27 N-m). BALANCER Removal 1. Remove belts and crankshaft pulley. 2. Remove balancer hub bolt and washer. 3. Using balancer puller, remove balancer as shown in Fig. 6A6-80. NOTICE: Use of any o th er type puller such as a universal claw type which pulls on the outside of the hub can destroy the harm onic balancer. The outside ring of the balancer is bonded in rubber to the hub; by pulling on the outside, rath er than the hub, it is possible to break the bond. The T .D .C . slot is on the outside ring of the balancer; if the bond between the hub and the outside ring is broken, the outside ring could slip which would change the location of the slot mark. If it is suspected th at the bond between the sections of the harm onic b alancer has been broken and the slot changed, it can be visually checked as shown in Fig. 6A6-81 The center of the keyway should be approx­ imately 16° from the center of the tim ing slot. In addition, there are chisel aligning m arks between the weight and hub, m arks should be together. 2. Install belt(s). A djust belts using Tool J-23600. Installation 1. A pply sealer # 1 0 5 0 8 0 5 , or equivalent, to inside diam eter of pulley hub and to crankshaft key to prevent possible oil leakage. C oat outside area of crankshaft pulley hub w hich enters seal w ith seal lu b rican t # 1050169, or equivalent. 2. Install balancer on crankshaft. Balancer to crankshaft fit is .001 " tight to .007 " loose. 3. Install washer and bolt. Torque 200-310 lb. ft. (271 420 N -m ). 4. Install pulley and belts. A djust belts using belt adjust­ ing gage J-23600. Torque pulley bolts to 10 lb. ft. (14N-m). FRONT COVER Removal 1. D rain cooling system. Disconnect radiator hoses and bypass hose. 2. Remove all belts, fan and fan pulley, crankshaft pulley and harm onic balancer, and accessory brackets. 3. Remove cover to block attaching bolts and remove cover, tim ing indicator and w ater pum p assembly. 4. Remove front cover and both dowel pins. It may be necessary to grind a flat on the pins to get a rough surface for gripping. Installation 1. G rind a cham fer on one end of each dowel pin as shown in Fig. 6A6-82. 2. C ut excess m aterial from front end of oil pan gasket on each side of engine block. 3. Clean block, oil pan and front cover m ating surfaces with solvent. 4. Trim about 1/8" (3m m ) from each end of new front pan seal, using a sharp tool as shown in Fig. 6A6-83. LIGHT TRUCK SERVICE MANUAL V8 - DIESEL 6A 6-33 6. Apply R.T.V. sealer (# 1 0 5 2 2 8 9 ) a t junction of block, pan and front cover as shown in Fig. 6A6-84 and 6A6- 86 . 7. Place cover on front of block and press downward to compress seal. R otate cover left and right and guide pan seal into cavity using a small screwdriver as shown in Fig. 6A6-85. 8. Apply engine oil to bolts (threads and heads). 9. Install two bolts finger tight to hold cover in place. 10. Install two dowel pins (cham fered end first). Fig. 6A6-82--Dowel Pin Chamfer Downward INJECTION P U M P D R IV E GEAR - P U SH CAM A G A IN S T REAR CUP PLUG KEY CRANKSHAFT SPROCKET 35 FT. LBS. GASKET (47 N-m I 1 FT. LBS. (30 N-m) 5. Install new front cover gasket on engine block and new front seal on front cover. Apply 1050805 or equivalent sealer to gasket around coolant holes and place on block. CAM SH A FT SPROCKET T IM IN G C H A IN CRANKSHAFT O IL SLINGER (SEAL TWO LOWER WATER P UM P BOLTS) Fig. 6A6-86--E ngine Front Cover Bolts LIGHT TRUCK SERVICE MANUAL 6A 6-34 V8 - DIESEL 11. Install tim ing in d icato r and w ater pum p assem bly. Then torque bolts evenly as shown in Fig. 6A6-86. 12. Apply lubricant # 1 0 5 0 1 6 9 or equivalent on balancer seal surface. 13. Install balancer and balancer bolt. Torque from 2003101b. ft. (271-420N -m ). 14. Install necessary brackets. 15. Connect bypass hose and radiator hoses. 16. In stall c ra n k sh a ft pulley and four a tta c h in g bolts. Torque to 20 lbs. ft. (27 N -m ). 17. Install fan pulley, fan and four attaching bolts. Torque bolts to 20 lbs. ft. (27 N-m ). 18. Install belts and adjust, using Tool J-23600. 19. Fill radiator. 20. Road test vehicle and check for leaks. Use of spray foot powder or equivalent m ay aid in detecting leaks. OIL SEAL Removal (Front Cover Installed) 1. Rem ove th e c ra n k sh a ft balan cer, See "B alan cer R em oval." 2. Remove oil seal. Fig. 6A6-88--Aligning Timing M arks Installation 1. A pply # 1 0 5 0 8 0 5 S ealer or equivalent, to outside diam eter of seal. 2. Using Tool J-25264 and Screw J-23952, install oil seal as shown in Fig. 6A6-87. 3. Install the pulley hub and crankshaft pulley. 4. Install and adjust belts using Tool J-23600. TIMING CHAIN AND GEARS Removal 1. Remove oil slinger, cam gear, crank gear and timing chain. 2. Remove fuel pum p eccentric from crankshaft if re­ placem ent is necessary. Installation 1. Install key in crankshaft if removed. 2. If removed, install fuel pum p eccentric. 3. Install cam sh aft gear, c ra n k sh a ft gear and tim ing chain together, and align tim ing m arks. (Fig. 6A6-88) 4. Torque cam shaft sprocket bolt to 65 lbs. ft. (88 N-m). • W hen the two m arks are in alignm ent, num ber six is at T.D .C . To obtain T .D .C . for num ber one cylinder, slowly rotate crankshaft one revolution. This will bring the cam m ark to the top, num ber one then will be in firing position. 5. Install oil slinger. • Any tim e the tim ing chain and gears are replaced, it will be necessary to retim e the engine. R efer to "M A R K IN G IN JE C T IO N P U M P A D A P T E R ". Fig. 6A6-32. CAMSHAFT, INJECTION PUMP DRIVE AND DRIVEN GEARS Removal 1. 2. 3. 4. 5. 6. 7. 8. 9. Fig. 6A6-87--Front Oil Seal Installation LIGHT TRUCK SERVICE MANUAL Disconnect battery. D rain coolant from engine. Remove upper radiator baffle. Disconnect upper radiator hose at w ater outlet. Disconnect upper radiator hose support clamp. Disconnect cooler lines at radiator. Remove radiator fan shroud. Remove radiator. Remove intake manifold and gasket, front and rear seal. 10. Remove balancer pulley. V 8 - DIESEL 6A 6-35 11. Remove balancer attaching bolt. 12. Remove balancer. 13. Remove engine front cover. INJECTION PUMP DRIVEN GEAR SH IM FUEL INJECTION PUMP SHAFT SPRING 14. Remove both valve covers. 15. Remove rocker arm s, push rods and valve lifters. Parts position should be noted so they will be installed in their original position. 16. If equipped w ith air conditioning, disch arge A /C system, remove condenser attaching bolts and remove condenser. CAUTION:: Always wear goggles and wrap a clean cloth around fittings and connections when doing work that involves opening the refrigeration system. If liquid refrigerant comes into contact with the skin or eyes, injury can result. 17. Remove bolt securing cam shaft gear and tim ing chain, then remove tim ing gears and chain. FUEL PUMP ECCENTRIC Fig. 6A6-90--lnjection Pump Driven Gear Shim 18. Position cam shaft dowel pin a t the 3 o’clock position. 19. W ith the cam shaft held rearw ard, remove pum p drive gear by sliding off the cam shaft while rocking the pump driven gear. INJECTION PUM P D RIVE GEAR PUSH C A M A G A IN ST REAR CU P PLUG 22 FT. LBS PO SIT IO N AT 20. If necessary to rem ove pum p driven gear, rem ove injection pump adapter, then remove snap ring and selective washer. Remove the driven gear and spring. 21. Remove cam shaft by carefully sliding it out the front of the engine. Do not force shaft as dam age can occur to cam shaft bearings. R efer to Fig. 6A6-86 for cam shaft identification. 22. If cam bearings are being replaced, it is necessary to remove oil pan. Refer to "O IL P A N R E M O V A L ". '3 O'CLOCK 'S ' CRANKSHAFT AND CAMSHAFT SPROCKET T IM IN G CH A IN 35 FT. LBS. GASKET CRANKSHAFT O IL SLINGER 22 FT. LBS. ENGINE T IM IN G INDICATOR Installation Any tim e the injection pum p adap ter is replaced or if pum p drive or driven gears or chain and gears are replaced, it is necessary to rem ark the tim ing m ark on the adapter. If either the pump drive or driven gears are to be replaced, replace BOTH gears. Fig. 6A6-91--Installing Injection Pump Drive Gear C oat cam shaft and bearings liberally with # 1 0 5 2 3 6 5 or equivalent before installing. C am shaft gear and crank­ shaft gear m ust be aligned as shown if Fig. 6A6-88. Check the injection pum p driven gear bushing, etc. Install the injection pum p driven gear, spring, shim and snap ring. Check the gear end play. If not within .002" to .006", replace the shim to obtain the clearance. (Fig. 6A690). Shims are available from .080" to .115" in .003" increm ents .094 " to . 115 ". Position the cam shaft dowel pin at 3 o’clock, algin the " O " m arks on the pump drive and driven gears. Then with the cam shaft held in the rearw ard position, slide the pump drive gear on the cam shaft. (Fig. 6A6-91). Tim ing indicator attaching stud m ust be installed and properly torqued before installing power steering pum p bracket. Bleed valve lifter. S ta rt engine, recharge A /C system, check for possible leaks. CAMSHAFT AND INJECTION PUMP DRIVEN GEAR BEARINGS The cam shaft bearings must be replaced in complete sets. All bearings m ust be removed before any can be LIGHT TRUCK SERVICE MANUAL 6A 6-36 V8 - DIESEL Fig. 6A6-92--Checking # 5 Oil Hole installed. # 1 bearing m ust be removed first, then # 2 , then 3, 4 and 5. W hen installing the bearings, # 5 m ust be installed first, then 4, 3, 2 and 1. C am shaft Bearing Remover and Installer J-6098-01 is available for this procedure. This set can be used to remove cam bearings with the engine either in or out of the vehicle. To replace bearings with engine in vehicle proceed as follows: Removal 1. Remove engine oil pan and cam shaft. 2. Install # 1 C am B earing Rem over and In staller J-25262 on H andle J-8092 and drive out front cam bearing. 3. Place Pilot on Driver and install # 2 C am bearing Tool on driver and drive out # 2 bearing. 4. Remove # 3 , 4 and 5 bearings in the sam e m anner. • Each cam bearing is a different diam eter and the correct sequence m ust be used both for removal and installation. 5. To remove the injection pum p driven gear bushings, drive both bushings at the same tim e from the rear to the front of the block using tool J-28439-2 and driver handle J-8092. Installation To aid aligning bearings with oil passages, place each bearing in the front bore with tapered edge tow ard block and align the oil hole in the bearing with the center of the oil slot in the bore. M ark bottom of bearing. W hen installing the bearings, the m ark will act as a guide. Slide bearing pilot spacer on bearing pilot. For bearings 5, 4, 3 and 2 put the driver through the pilot, then screw the installer on the driver. Install the bearings as follows: LIGHT TRUCK SERVICE MANUAL 1. Place new # 5 bearing on driver and drive bearing in until the last white line on the driver is flush with the front face of the pilot. 2. Use a piece of 3 /3 2 " (2.4m m ) brass rod with a 90° bend at the end to check the oil hole opening as shown in Fig. 6A6-92. 3. Place # 4 bearing on installer and drive in until the next to last white line on driver is flush with pilot. 4. Follow the same procedure to install # 3 and # 2. 5. Place # 1 bearing on installer. Drive bearing in until it is flush with front face of block. 6. To install the injection pum p bushings, align the holes in the bushings with the holes in the block. Install both bushings from the front; driving the rear bushing first, using the long end of tool J-28439-1 and driver handle J-8092. Drive the front bushing with the short end of J-28439-1. 7. Use a piece of 3 /3 2 " (2.4m m ) brass rod with a 90° bend a t the end to check all oil hole openings. W ire must enter hole or the bearing will not receive sufficient lubrication. (See Fig. 6A 6-92). 8. Install cam shaft and engine oil pan. Camshaft and Oil Gallery Plugs (Fig. 6A6-93) The left-hand rear oil gallery plug is not shown. It is a threaded plug in the end of the left gallery just rearw ard of the vacuum pump. A small hole is provided in the plug for vacuum pump lubrication. The cup plug shown provides access to the threaded plug. The front oil gallery plugs (not shown) are threaded. The plug on the right side has a small hole which provides lubrication for the tim ing chain and gears. To find out if the cam shaft plug at the rear of the engine is properly installed, place a straight edge across the m achined surface of the rear of the block and m easure from the straight edge to the lip of the plug. Dimension should be 4.8 mm (.1 9 0 ") m axim um to 3.8mm (.1 5 0 ") m inim um . V 8 - DIESEL 6A 6-37 UNIT REPAIR ENGINE Removal 1. D rain cooling system. THREAD 2. Remove air cleaner and install screened cover J-269961. PROTECTORS 3. Remove hood from hinges, m ark hood for reassembly. 4. Disconnect battery negative cables at batteries and ground wires at inner fender panel. Disconnect engine ground strap. 5. Disconnect radiator hoses, cooler lines, heater hoses, vacuum hoses, power steering pum p hoses at power steering gear, air conditioning com pressor with brack­ ets and hoses attached, fuel hose from fuel pump and wiring. / RUBBER " 'V B A N D S NOTE O VERLA P OF ADJACENT RODS 6. Remove hairpin clip at bellcrank. 7. Remove throttle cable from intake manifold bracket, then position cable away from engine. 8. Remove upper radiator support and radiator. 9. Raise vehicle. 10. Disconnect exhaust pipes at manifolds. 11. Remove torque converter cover and three bolts holding converter to flywheel. FRONT OF ENGINE 12. Remove engine m ount through bolts. 13. Remove three bolts, transm ission to engine on the right side. Disconnect wires from starter and remove starter. 14. Lower vehicle. 15. Place board on top of jack and slightly raise transm is­ sion. Remove three left transm ission to engine bolts. Remove engine. 16. If vehicle is to be moved, install converter holding tool J - 2 1654 and support transm ission with chain support. Installation 1. In stall engine in place. L ocate engine dowels into transm ission and position through bolts into mounts and tighten. Install three left transm ission to engine bolts. Remove support chains and jack. 2. Raise vehicle. Replace three transm ission to engine bolts on the right side. Replace starter and attaching bolts and attach wires. 3. Install three converter to flywheel bolts and torque converter cover bolts to 40 lbs. ft. (54 N -m ). 4. C onnect exhaust pipes and lower vehicle. 5. Install radiator and upper radiato r support. 6. C onnect ra d ia to r hoses, cooler lines, h eater hoses, vacuum hoses, power steering pum p hoses at pump, power steering hose bracket to engine, air conditioning compressor, fuel hose to fuel pum p and wiring. 7. Position bellcran k and cables to intak e m anifold. Install bellcrank. In stall th ro ttle rod to bellcrank. Connect b reather pipes and connect fuel return line to pump. 8. Install air cleaner. 9. Install and align hood with scribe marks. 10. Connect battery cables and ground wires. 11. Add engine oil and coolant. Fig. 6A6-94--Crankshaft Removal CRANKSHAFT Removal (Cylinder Heads On) 1. W ith engine on stand and oil pan, oil pump and front cover removed, rotate crankshaft to the position where the connecting rod nuts are most accessible. Fig. 6A694 shows the engine with the # 3 and # 4 rods in the fully extended position. 2. Remove connecting rod caps and install thread protec­ tors. Remove fuel pum p eccentric from crankshaft. 3. Remove main bearing caps. 4. N ote position of keyway in crankshaft so it can be installed in the same position. 5. Lift crankshaft out of block. Rods will pivot to the center of the engine when the crankshaft is removed. Do not allow pistons to move in their bore during or after crankshaft removal. Installation 1. Install sufficient oil pan bolts in pan rails to align rods with rubber bands. Align rods so th at the inner thread protectors of adjacent rods overlap approxim ately one inch as shown. A lignm ent can be adjusted by increas­ ing tension on ru b b er bands w ith additional tu rn s around the pan bolts or thread protectors. 2. M easure the crankshaft journals and crankpins with a m icrom eter to determ ine the correct size rod and main bearings to be used. • W henever a new or reconditioned cran k sh aft is installed, new connecting rod bearings and main bearings should be installed. 3. Position crankshaft keyway in the sam e position as removed and lower into block. The connecting rods will LIGHT TRUCK SERVICE MANUAL 6A6-38 V8 - DIESEL follow the crankpins into the correct position as the crankshaft is lowered. 4. Remove rubber bands, thread protectors and pan bolts and assemble engine. CENTER M A IN BEARING THRUST FLANGES NOTICE: In order to prevent the possibility of cylinder block and/or main bearing cap damage, the main bearing caps are to be tapped into their cylinder block cavity using a brass or leather mallet before attaching bolts are installed. Do not use attaching bolts to pull main bearing caps into their seats. Failure to observe this information may damage a cylinder block or bearing cap. WOOD BLOCK B U M P SHAFT IN EACH Removal (Cylinder Heads Removed) 1. With engine on stand, remove oil pan, front cover, connecting rods, oil pump and fuel pump eccentric from crankshaft. 2. Remove main bearing caps and lift crankshaft out of block. DIRECTION TO A LIG N THRUST FLANGES O F -------/^CENTER M A IN BEARIN G ----- ^ ------x Fig. 6A6-96--Aligning Center Main Bearing Flanges Installation 1. Measure the crankshaft journals and crankpins with a micrometer to determine the correct size rod and main bearings to be used. • W henever a new or reconditioned crankshaft is installed, new connecting rod bearings and main bearings should be installed. R.H. O IL P ASSAG E PLUG .^ .p .p f M Q .O - O llP A S S A C E L H . O IL / P ASSAG E PLUG y ° ^ i /- — J \ C U P P lU G L H. O IL PASSAG E PLUG --------C RANKSHAFT REAR BEARING SEAL CRANKSHAFT 2. Position upper half of main bearings in block and lubricate with engine oil. 3. Install a new rear main bearing seal. (Fig. 6A6-95). Rear bearing must be removed to replace seal. 4. After oil passages in crankshaft have been checked for being open and shaft is clean, place shaft in block. Lubricate thrust flanges of the center bearing with \ J_ GROOVES IN UPPER AND LOWER HALF OF ALL BEA R IN G S EXCEPT NUMBER ONE. NUMBER ONE LOWER DOES NOT HAVE A GROOVE. 120 FT. LBS. Fig. 6A6-97--Crankshaft-Exploded View # 1 0 5 0 1 6 9 Lubricant or equivalent. Install caps with lower half of bearing lubricated with engine oil. Lubricate cap bolts with engine oil and install, but do not tighten. 5. With a block of wood (Fig. 6A6-96) bump shaft in each direction to align thrust flanges of center main bearing. After bumping shaft in each direction, wedge the shaft to the front and hold it while torquing # 3 cap bolts. 6. Torque all main bearing bolts to 120 lbs. ft. (163 N-m). (Fig. 6A6-97). 7. Reassemble engine and install in chassis. NOTICE: In order to prevent the possibility of cylinder block and/or main bearing cap damage, on all engines including diesels, the main bearing caps are to be tapped into their cylinder block cavity using a brass or leather mallet before attaching bolts are installed. Do not use attaching bolts to pull main bearing caps into their seats. Failure to observe information may damage cylinder block or bearing cap. MAIN BEARINGS Main bearing clearance must not exceed .0035" on all bearings. The .0035" clearance is permissible only if the LIG H T T R U C K SE RV IC E M A N U A L V8 - DIESEL 6A6-39 engine is disassembled for other than a bearing noise condition. If bearings are noisy or if a visual inspection indicates defective bearings, new bearings must be installed within the specifications outlined under M A IN BEARINGS-REPLACE. Bearings which fall within the .0035" specifications should not be replaced if the bearings show normal wear pattern or slight radial grooves. Checking Bearing Clearances 1. Remove bearing cap and wipe oil from crankshaft journal and outer and inner surfaces of bearing shell. 2. Place a piece of plastic gaging material in the center of bearing. 3. Use a floor jack or other means to hold crankshaft against upper bearing shell. This is necessary to obtain accurate clearance readings when using plastic gaging material. 4. Reinstall bearing cap and bearing. Place engine oil on cap bolts and install. Torque bolts to 120 lbs. ft. (163 N-m). 5. Remove bearing cap and determine bearing clearance by comparing the width of the flattened plastic gaging material at its widest point with graduations on the gaging material container. The number within the graduation on the envelope indicates the clearance in thousandths of an inch. (Fig. 6A 6-98). If the clearance is greater than .0035", REPLACE BOTH BEARING SH ELLS AS A SET. Recheck clearance after replac­ ing shells. (Refer to M A IN BEARING S-REPLACE) Main bearing end thrust clearance should be .0035" to .0135 " as checked with a dial indicator. COAT SEAL GROOVE. ENDS OF SEAL AND AREA INDICATED WITH 1050026 SEALER OR EQUIVALENT. J-28693 SEALER Main Bearings Replacement Main bearing clearances must be corrected by the use of selective upper and lower shells. U N D E R N O CIR­ C U M STA N C E S should the use of shims behind the shells, to compensate for wear, be attempted. The upper and lower shells must be installed in pairs. Sizes of the bearings are located on the tang. (Fig. 6A6-99). AFTER CORRECTLY PO SITION IN G SEAL, ROTATE TOOL SLIGHTLY AND CUT OFF EACH END OF SEAL FLUSH WITH CAP. Fig. 6A6-100--lnstalling Rear Main Oil Seal It is possible to have more than one bearing size in the same engine. To install main bearing shells, proceed as follows: 1. Loosen all main bearing caps. 2. Remove bearing cap and remove lower shell. 3. Insert a flattened cotter pin or roll out pin in the oil passage hole in the crankshaft, then rotate the crank­ shaft in the direction opposite to cranking rotation. The pin will contact the upper shell and roll it out. 4. The main bearing journals should be checked for roughness and wear. Slight roughness may be removed with a fine grit polishing cloth saturated with engine oil. Burrs may be removed with a fine oil stone. If the L IG H T T R U C K SERVICE M AN U AL 6A6-40 5. 6. 7. 8. 9. 10. V8 - DIESEL journals are scored or ridged, the crankshaft must be replaced. • The journals can be measured for out-of-round with the crankshaft installed by using a crankshaft caliper and inside micrometer or a main bearing microme­ ter. The upper bearing shell must be removed when measuring the crankshaft journals. Maximum outof-round of the crankshaft journals must not exceed .0015". Clean crankshaft journals and bearing caps thoroughly before installing new main bearings. Apply Special Lubricant, # 1 0 5 0 1 6 9 or equivalent, to the thrust flanges of bearing shells on # 3 bearing. Place new upper shell on crankshaft journal with locating tang in correct position and rotate shaft to turn it into place using cotter pin or roll out pin as during removal. Place new bearing shell in bearing cap. # 5 bearing - Install new asbestos oil seal in the rear main bearing cap. (REAR M A IN BEARING OIL SEAL) (Fig. 6A 6-100) Install # 1 0 5 0 0 2 6 or equiv­ alent sealer on cap as shown. Install bearing caps, lubricate bolt threads with engine oil, then install. Torque bolts to 120 lbs. ft. (163 N-m). NOTICE: In order to prevent the possibility of cylinder block and/or main bearing cap damage, the main bearing caps are to be tapped into their cylinder block cavity using a brass or leather mallet before attaching bolts are installed. Do not use attaching bolts to pull main bearing caps into their seats. Failure to observe this information may damage a cylinder block or bearing cap. REAR MAIN BEARING UPPER OIL SEAL Repair Tools have been released to provide a means of correct­ ing engine rear main bearing upper seal leaks without the necessity of removing the crankshaft. The procedure for seal leak correction is listed below. 1. Drain oil and remove oil pan and rear main bearing cap. 2. Insert Packing Tool BT-6433 against one end of seal in cylinder block and drive the old seal gently into the groove until it is packed tight. This varies from 1/4" (6mm) to 3/4" (19mm), depending on the amount of pack required. (Fig. 6A6-101). 3. Repeat this on the other end of the seal in the cylinder block. 4. Measure the amount the seal was driven up on one side; add 1/16" (1.6mm), then cut this length from the old seal removed from the main bearing cap with a single edge razor blade. Measure the amount the seal was driven up on the other side. Add 1/16" (1.6mm) and cut another length from old seal. Use main bearing cap as a holding fixture when cutting seal as shown in Fig. 6A6-102. 5. Place a drop of # 1 0 5 0 0 2 6 Sealer or equivalent, on each end of seal and cap as indicated. 6. Work these two pieces of seal into the cylinder block (one piece on each side) with two small screwdrivers. Using Packing Tool, pack these short pieces up into the block. 7. Form a new rope seal in the rear main bearing cap as outlined. 8. Assem ble the cap to the block and torque to specifications. NOTICE: In order to prevent the possibility of cylinder Fig. 6A6-101--Packing Oil Seal LIG H T T R U C K SERVIC E M A N U A L block and/or main bearing cap damage, the main bearing caps are to be tapped into their cylinder block cavity using a brass or leather mallet before attaching bolts are installed. Do not use attaching bolts to pull main bearing caps into their seats. Failure to observe this information may damage a cylinder block or bearing cap. V8 - DIESEL 6A6-41 REAR MAIN BEARING LOWER OIL SEAL FLEX PLATE Removal One bolt hole in the flex plate is offset and the flywheel will attach to the crankshaft in only one position. The flex plate ring gear is not replaceable. 1. 2. 3. 4. Remove oil pan. Remove the rear main bearing cap. Remove rear main bearing insert and old seal. Clean bearing cap and seal grooves and inspect for cracks. ENGINE OIL DIPSTICK AND DIPSTICK GUIDES (Fig. 6A6-103) Removal Installation 1. Install seal into bearing cap, packing by hand. 2. Using seal installer, hammer seal into groove (Fig. 6A 6-100). To check if seal is fully seated in the bearing cap, slide the tool away from seal. With tool fully seated in the bearing cap, slide tool against the seal. If undercut area of tool slides over the seal, the seal is fully seated. If tool butts against the seal, the seal must be driven further into the seal groove. Rotate tool before cutting off excess seal packing. 3. With tool slightly rotated, cut seal flush with mating surface. With screwdriver, pack seal end fibers towards center, away from edges. Rotate seal installer when cutting seal to avoid damage to tool. 4. Clean bearing insert and install in bearing cap. 5. Clean crankshaft bearing journal and seal contact. Install sealer on cap as shown. NOTICE: In order to prevent the possibility of cylinder block and/or main bearing cap dam age, the main bearing caps are to be tapped into their cylinder block cavity using a brass or leather mallet before attaching bolts are installed. Do not use attaching bolts to pull main bearing caps into their seats. Failure to observe this information may dam age a cylinder block or bearing cap. 6. Install bearing caps, lubricate bolt threads with engine oil and install. Torque bolts to 120 lbs. ft. (163 N-m). 7. Install pan with new gaskets. 8. Install lower flex plate cover. Removal of the dipstick guide will assist in easier removal and installation of the left cylinder head. Before removing the left cylinder head, the guide can be removed using the following procedure: 1. Position the slide hammer from Tool J-2619 on a 1/4" (6mm) diameter 6 " (1 52mm) long bolt. 2. Insert the threaded end of the bolt into the oil dipstick guide and clamp with a vise grip type pliers. 3. Use slide hammer to tap out tube. To install, insert a 1/4" (6m m ) diameter x 1/2" (13mm) long bolt into the tube and tap on the bolt head to drive tube into the block. 4 FRONT OF ENGINE P O SIT IO N GUIDE TO REAR OF OPENING EXH AU ST M AN IFO LD D IP S T IC K GUI •V . -- 45 «.,? CENTER LINE OF O PENING IN EXHAUST M A N IFO LD GUIDE______ I— 11 21/64"- r j ■17 7/32 (YELLOW P L A ST IC PLUG AND HANDLE COATING) Fig. 6A6-103--Engine Oil Dipstick Identification LIG H T T R U C K SERVICE M A N U A L DRIVE AND VACUUM PUMPS GENERAL DESCRIPTION The vacuum pump is used to provide vacuum required for some accessories. It is a diaphragm pump which needs no periodic maintenance. It is driven by a cam inside the drive assembly to which it mounts. The pump’s diaphragm moves back and forth causing air to flow into the inlet tube, through the pump, and exhaust out the rear port. The vacuum pump is driven two ways, gear driven and belt driven. The gear driven pump has a drive gear on the lower end which meshes with the cam shaft gear in the engine. This drive gear causes the cam in the drive housing to rotate. The drive gear also powers the engine oil lubricating pump. The belt driven pump has a pulley attached to the shaft at the lower end of the housing assembly. The pump pulley is driven off the belt cluster at the front of the engine. Fig. 6A6-104--Vacuum CAUTION: Do not operate engine w itho u t drive and vacuum pum p assembly as this is also the drive for the engine oil p um p (gear driven p u m p only) Pump K ey N o. D R IV E G EAR 1 2 3 4 — — — — P a rt N a m e PU M P ASSY, V A C U U M SCREW , HEX.H E A D T A P P IN G SEAL, “O" RING DR IVE ASSY, V A C U U M PU M P (G EAR D RIVEN ) - SERVICE C O M P O N E N TS Key No. 1 2 3 4 5 — — — — — Part Name PU M P AS SY , V A C U U M SC REW , HE X H E A D T A P P IN G SEAL, “O ” R IN G D R IV E AS SY , V A C U U M PU M P B O LT AS SY , SE AL & (B E L T D R IVE N ) - S ER V IC E C O M P O N E N T S V8 - DIESEL REMOVE AND INSTALL (GEAR DRIVEN) REMOVE INSTALL R e m o ve h o se fro m p u m p in le t. R e m o ve b o lt a nd b ra c k e t h o ld in g p u m p to e n g in e b lo ck. R e m o ve p u m p . x V A C U U M HOSE In s e rt p u m p in e n g in e , m a k in g s u re th e g ea rs o n th e p u m p m esh w ith th e g e a rs o n th e e n g in e ca m sh a ft. R o ta te th e p u m p in to p o s itio n so th e b ra c k e t a n d b o lt ca n be in s ta lle d . 6A6-43 DISASSEMBLE AND ASSEMBLE CAUTION: Take extrem e care when c la m p in g the vacuum p u m p in vise. DISASSEMBLE 1. R e m o v e hex head ta p p in g s c re w s . ASSEMBLE 1. In s ta ll " O ” R in g Seal in c a v ity o f d riv e 2. R e m o v e “ O ” R in g Seal a s s e m b ly . 2. C o n n e c t d riv e a s s e m b ly to v a c u u m p u m p w ith h e x hea d ta p p in g s c re w s . In s ta ll v a c u u m h ose . O ” R IN G S E A L D RIVE & V A C U U M PU M P A S S E M B LY BO LT Install Seal “O" Ring BRACKET in cavity of drive assembly. S c re w s s h o u ld be tig h te n e d e v e n ly a n d to a to rq u e o f 12 N *m (9 Ft. L bs.) j REMOVE AND INSTALL (BELT DRIVEN) REMOVE R e m o ve b e lt fro m p u m p a sse m b ly. 1. In s ta ll p u m p to m o u n tin g o n e n g in e . R e m o ve hose fro m p u m p in le t. 2. In s ta ll v a c u u m hose, 3 |nstaM b e |t jn R e m o ve b o lts h o ld in g p u m p to b ra c k e t. C la m p a s s e m b ly in vise in a rea s h o w n . C a re s h o u ld be ta k e n n o t to o v e r tig h te n . INSTALL T h e g e a r s h o u ld be fre e to tu rn w h e n in s ta llin g th e s c re w s to th e p u m p a s s e m b ly . p u lle y a nd a d ju s t b e lt te n s io n . R e m o ve p u m p . T h e b e a rin g a s s e m b ly in th e b e lt d riv e n p u m p n e e d s lu b ric a n t. T h is s h o u ld be c h e c k e d a n d k e p t fille d a t a ll tim e s (see b e lo w ). Seal a n d b o lt a s s e m b ly tig h te n to 4 to 6 N «m (4 Ft. Lbs.) F ill w ith 1052271 (S A E 80W--90) g e a r lu b ric a n t (b e lt d riv e n p u m p o n ly ) T h e s h a ft s h o u ld be fre e to tu rn w h e n in s ta llin g th e s c re w s to th e p u m p a s s e m b ly . Fig. 6A6‘ 105--Vacuum Pump Service LIG H T TR U C K SE R V IC E M AN U AL PISTON PIN V -8 D IE S E L DISPLACEMENT LITRE {*) 5 .7 (N ) LF9 DIAMETER 1 .0 9 4 9 -1 .0 9 5 3 PRODUCTION CLEARANCE .0 0 0 3 -.0 0 0 5 SERVICE RPO LF9 BORE 4 .0 5 7 STROKE 3 .3 8 5 COMPRESSION RATIO 2 2 .5 :1 FIRING ORDER 1 - 8 - 4 - 3 - 6 - 5 -7 -2 DIAMETER OUT OF ROUND TAPER FIT IN ROD i A rtH PRODUCTION PRODUC­ TION N .A . RELIEF SIDE N .A . SERVICE PRODUCTION N .A . SERVICE N .A . PRODUCTION N .A . SERVICE N .A . # 1 -2 -3 -4 .0 0 0 5 -.0 0 2 1 MAIN BEARING CLEARANCE #5 .0 0 1 5 -.0 0 3 1 N .A . PISTON: CLEARANCE OUT OF ROUND N .A . THRUST SIDE ALL 2 .9 9 9 3 -3 .0 0 0 3 DIAMETER 4 .0 5 6 -4 .0 5 8 SERVICE .0 0 0 3 -.0 0 1 3 CRANKSHAFT MAIN JOURNAL CYLINDER BORE: N .A . SERVICE N .A . CRANKSHAFT END PLAY PRODUCTION N.A. SERVICE . 0 0 5 " — .0 0 6 ” PISTON RING: t 0 GROOVE PRODUC­ * V IN D e s ig n a tio n DIAMETER PRODUCTION CRANKPIN TOP M CLEAR­ TION 2ND P ANCE R SERVICE E S PRODUC­ TOP S TION 2ND GAP 1 o SERVICE N GROOVE PRODUCTION CLEAR 0 ANCE SERVICE 1 PRODUCTION L GAP SERVICE .0 0 5 -.0 0 7 OUT OF ROUND .0 0 1 8 -.0 0 3 8 N .A . .0 1 5 -.0 2 5 .0 1 5 *.0 2 5 N .A . .0 0 1 -.0 0 5 N .A . .0 1 5 -.0 5 5 N .A . .0 0 3 5 -.0 1 3 5 ROD BEARING CLEARANCE 2 .1 2 3 8 -2 .1 2 4 8 N .A . ................................ (... SERVICE N .A . PRODUCTION N .A . SERVICE PRODUCTION N .A . .0 0 0 5 -.0 0 2 6 SERVICE ROD SIDE CLEARANCE N .A . .0 0 6 -.0 2 0 CAMSHAFT LOBE LIFT ± .002 INTAKE N .A . EXHAUST JOURNAL DIAMETER CAMSHAFT END PLAY N .A . #1 2 0357 2 0365 #2 2.0157-2 0166 #3 1 9957 1 9965 #4 1 9757 1 9765 #5 1.9567-1.9566 .0 1 1 -.0 7 7 V8 - DIESEL TYPE 6A6-44 GENERAL DATA: TORQUE SPECIFICATIONS Ib. ft. V A L V E SYSTEM LF9 LIFTER HYDRAULIC ROCKER ARM RATIO N.A. VALVE LASH INTAKE NONADJUSTABLE EXHAUST FACE ANGLE (INT. & EXH.) SEAT ANGLE (INT. & EXH.) SEAT WIDTH .075.098 INTAKE EXHAUST .037-.075 INT. PRODUCTION STEM EXH. CLEARANCE SERVICE FREE LENGTH VALVE SPRING (OUTER) PRESSURE LBS. e IN. * .003 SEAT RUNOUT T5 @ .0010-.0027 .0015-.0032 N.A. 2.09 CLOSED 85-95 @ 1.670 OPEN 203-207 @ 1.300 INSTALLED HEIGHT N.A. ± 1/32" FREE LENGTH N.A. APPROX. # OF COILS N.A. DAMPER @ — 44° INTAKE — 30° EXHAUST * — 45° INTAKE — 31° EXHAUST N-m LIGHT TRUCK Injection Pump A tta ch ing Nuts ...................... .......... 19. .___ 26 Injection Line Nut To Pum p .................. ..........25. ■ . . . 34 Injection Pum p A da pter B o lts .................... .......... 25- • . . . 34 Injection Line Nut To N o z z le ............ .......... 25- . . . . 34 Injection Pum p Fuel Filter Inlet L in e .............. ..........20. . . . . 27 Injection Pum p Fuel Filter O utlet L i n e .......... ..........18. . . . . 24 Injection Pum p Fuel Inlet Line ........................ ..........20. . . . . 27 Injection Nozzle H old-D ow n C la m p ................ ..........25. . . . . 34 G lo w P lu g .............................................................. ..........12. . . . . 16 Crankshaft Bearing Cap B o lts .......................... ........120. . , . 163 Flywheel To C o n v e rte r...................................... ..........40. . . . . 54 Flywheel To C rankshaft .................................... ..........60. . . . . 81 Oil Pum p To Bearing Cap B o lt s ...................... ..........35. . . . . 47 Oil Pum p Cover To Pum p B o lt s ...................... ............8. . . . . 11 Rocker A rm Pivot B olt To H e a d ...................... ..........28 . . . . 38 Valve Cover Bolts Fully Driven, Seated, Not Stripped Oil Pan Bolts ........................................................ ..........10. . . . . 14 Oil Pan Drain Plug .............................................. ..........30. . . . . 41 Crankshaft Balancer To C rankshaft Bolt . . . . .200-310. . 2 7 1 -4 ; Oil Filter Elem ent To B a s e ................................ ..........20 - . . . . 27 Oil Filter A ssem bly To C ylinder Block Bolts . ..........35- • . . . 47 Oil C ooler Lines To Oil Filter Base ................ ..........12- ■ . . . 16 Oil C ooler Lines To R a d ia to r............................ ..........25- • . . . 34 S upport/F ront Cover To C ylinder Block Bolts 3/8" .............................................................. ..........35- • . . . 34 Fan Driven Pulley To Hub B o lt s ...................... ..........20 . . . . . 27 Fan D riving Pulley To Balancer B o lt s ............ ..........20. . . . . 27 W ater Pum p To Front Cover Bolts ................ ..........13. - . . . 18 W ater O utlet To M anifold B o lt s ...................... ..........20. . . . . 27 *lntake M a n ifold To C ylinder Head Bolts . . . ..........40. . . . . 54 Exhaust M a n ifold To C ylinder Head Bolts .. ..........25. . . . . 34 Engine M o u n t To C ylinder Block Bolts ........ ..........75. . . . 102 Engine M o u n t To Frame M o u n t...................... ..........50. . . . . 68 Starter To C ylinder Block Bolts ...................... ..........35. . . . . 47 Starter Brace To C ylinder Block Bolts .......... ..........25. . . . . 34 S tarter Brace To Starter B o lt............................ ..........15. . . . . 20 Vaccum Pum p C lam p To C ylinder Block Bolt ........ 17. . . . . 23 *C ylin d e r Head B o lts .......................................... ........130. . . . 176 C onnecting Rod Nuts ........................................ ..........42. . . . . 57 C am shaft Sprocket Bolt .................................... ..........65. . 88 SERVICE * Clean and d ip entire bolt in engine oil before tig htening to obtain a correct torq ue reading. M AN U AL ENGINE COOLING 6B-1 SECTION 6B ENGINE COOLING CONTENTS General Description......................................................... .6B-1 Coolant Level.................................................................. ..6 B -1 Thermostat................. ..................................................... ..6B-2 Drive B elts....................................................................... .6B-7 Diagnosis...............................................................................6B-7 System C hecks................................................................ .6B-7 O verheat/N oise............................................................... ..6B-7 Fan C lu tch....................................................................... .6B-8 On Vehicle S ervice........................................................... Water Pump..................................................................... Thermostat....................................................................... Radiator............................................................................ Fan Shroud...................................................................... Fan/Fan C lutch.............................................................. Coolant Recovery Bottle............................................... Engine Oil C ooler........................................................... 6 B -1 1 6B-11 6B-11 6B-12 6B-12 6B-12 6B-13 6B-14 GENERAL DESCRIPTION All Chevrolet Light Duty Trucks have pressure type engine cooling systems with thermostatic control of coolant circulation. The cooling system is sealed by a pressure type radiator filler cap which causes the system to operate at higher than atmospheric pressure. The higher pressure raises the boiling point of the coolant which increases the cooling efficiency of the radiator. The 15 pound (103 kPa) pressure cap used raises the boiling point of coolant to approximately 258° F (125°C) at sea level. The radiator cap should be washed with clean water and pressure checked every 12 months. All models have a closed cooling system using a round pressure cap (Fig. 6B-1) and a coolant reservoir. Coolant can be added without removing the radiator cap. A pressure-vacuum valve radiator cap is used which allows the coolant to expand through the pressure valve in the center of the cap without building unnecessary pressure. The expanding coolant flows into the coolant reservoir. The vent valve closes due to expansion and coolant flow. The nominal 15 pound (103 kPa) pressure will not be reached until the system is working at maximum capacity. Any air or vapor in the cooling system will be forced to the coolant reservoir under the liquid level and leave through the vent tube at the top of the reservoir. As the system cools, the extra coolant in the reservoir will be drawn back to the radiator through the vent valve. In this manner, the radiator will keep itself full at all times. COOLANT LEVEL The need for additional coolant can be detected by observing the level of coolant in the "see through" reservoir while the engine is at normal operating temperature. The radiator cap need not normally be removed. The coolant level should be at the "Full Cold" mark when the system is cool or at ambient temperature. After the vehicle has been driven sufficiently to obtain normal operating temperatures, the level should be above the "Full Cold" mark. Periodically, the radiator cap should be removed to observe coolant level in the radiator. CAUTION:The radiator coolant level should only be checked when the engine is cool. If the radiator cap is removed from a hot cooling system, serious personal injury may result. Coolant levels in crossflow radiators with coolant recovery bottles should be maintained to the top of the filler neck. The recovery bottle should be at its appropriate mark when checked. Regardless of whether freezing temperatures are expected or not, cooling system protection should be maintained at least to -34°F (-37°C), to provide adequate corrosion protection and loss of coolant from boiling. With glycol content less than requirement for -34°F (-37°C ) protection, coolant boiling point is less than the temperature indicating light setting. When adding solution due to loss of coolant for any reason or in areas where temperatures lower than -34°F (-37°C) may occur, a sufficient amount of an ethylene glycol base anti-freeze that meets GM Specifica­ tion 1899-M should be used. NOTICE: Alcohol or methanol base anti-freeze, or plain water, are not recommended for your engine at any­ time. They will not provide proper protection against corrosion. Flushing Cooling System Fig. 6B-1--Radiator Pressure Cap Various methods and equipment may be used to perform this service. If special equipment such as a back flusher is used, equipment manufacturer’s instructions should be followed. However, it is advisable to remove the thermostat before flushing the system. LIG H T T R U C K SE RV IC E M AN U AL 6B-2 ENGINE COOLING THERMOSTAT The thermostat consists of a restriction valve actuated by a thermostatic element. This is mounted in the housing at the cylinder head coolant outlet above the water pump on L-6, and in the forward part of the intake manifold, under the coolant outlet on "small block" and "Mark". Thermo­ stats are designed to open and close at predetermined temperatures and if not operating properly should be removed and tested. ALL L6 ENGINES AND ALL V8 ENGINES EXCEPT DIESEL GENERATOR A.I.R. PUMP P/S PUMP 50 LB. (222 N) MIN. A/C COMPRESSOR 65 LB. (289 N) MIN. ADJUST TO 75 + 5 LBS. USED (334 ± 22 N) ADJUST TO 125 ± 5 LBS. NEW (556 + 22 N) ADJUST TO 95 ± 5 LBS. USED (423 + 22 N) ADJUST TO 140 ± 5 LBS. NEW (623 ± 22 N) 5.7L — V8 DIESEL GENERATOR P/S PUMP A.I.R. PUMP (NON A/C) 70 LB. (311 N) MIN. A/C COMPRESSOR A.I.R. PUMP 80 LB. (356 N) MIN. ADJUST TO 75 ± 5 LBS. USED (334 ± 22 N) ADJUST TO 110-140 LBS. NEW (480-623 N) ADJUST TO 90 ± 5 LBS. USED (400 ± 22 N) ADJUST TO 135-165 LBS. USED (600-734 N) Fig. 6B-2--Drive Belt Tension Specifications LIG H T T R U C K SE RV IC E M A N U A L ENGINE COOLING ADJU STM EN T BOLT DJUSTM ENT BOLT IN LIN E PIVOT BOLT 6B-3 IN L IN E /L 2 5 PIVOT BOLT VIEW ADJU STM EN T BO LT PIVO T BOLT S M A L L BLOCK DIESEL - EXCEPT A /C ADJU STM EN T BOLT PIVO T BOLT PIV O T BOLT [ v i ew] ADJU STM EN T BOLTS A D IE S E L -A /C EQUIPPED Fig. 6B-3--Generator Adjustment 6B-4 ENGINE COOLING IIM LINE/LE3 IN |iN E /W 5 ^ " B0LT ^ ^ ADJUSTMENT NUT A D JUSTM EN^^ SMALL BLOCK - *P' & 'G' SMALL BLOCK-EXCEPT 'P' & 'G' ADJUSTMENT -W ' ll ^^JPIVOT BOLT NUT & NUT MK IV DIESEL Fig. 6B-4--P/S Pump Adjustment ENGINE COOLING 6B-5 PIVOT BOLT & NUT ADJUSTMENT BOLT PIVOT BOLT ADJUSTMENT 'I BOLT ADJUSTMENT BOLT IN LINE-'G' MODEL ■BRACE ADJUSTING BOLT .SUPPORT ADJUSTMENT BOLTS.! V PIVOT BOLT A L L W ITH SM ALL BLOCK & C-69 ^ LOOSEN (4) AND TURN ADJUSTING BOLT VIEW SMALL BLOCK-EXCEPT 'G ', LS9, LT9, L69 SMALL BLOCK 'G' MODEL .BRACE ADJUSTMENT BOLT \ SUPPORT, .SUPPORT TAPPED HOLE ■PIVOT BOLT .ADJUSTMENT/ BOLTS PIVOT BOLT Fig. 6B-5--A/C Compressor Adjustment LIG H T T R U C K SERVICE M AN U AL 6B-6 ENGINE COOLING Fig. 6B-5A--A/C and A.I.R. Adjustment L IG H T T R U C K SE RV IC E M A N U A L ENGINE COOLING DRIVE BELTS Frayed or cracked belts should be replaced and tensioned to specifications using a strand tension gage, such as tool J-23600-B or equivalent. Loose belts may place an extremely high impact load on driven component bearings due to the whipping action of the belt. An over tightened belt places unnecessary loads on the component bearings. 6B-7 In figure 6B-2, the minimum reading is the lowest allowable setting before the belt must be reset. When readjusting, the adjustment specification should be met. When adjusting a drive belt, it is important that the proper adjustment specification be used. Refer to figures 6B-3 thru 6B-5 for adjustment. • A ’Used’ belt is one that has been rotated at least one complete revolution on engine pulleys. This begins the ’seating’ of the belt and it should never be reset to ’N ew ’ belt specifications. DIAGNOSIS If the cooling system requires frequent addition of coolant in order to maintain the proper level, check all units and connections in the cooling system for evidence of leakage. Inspection should be made with cooling system cold. Small leaks which may show dampness or dripping can easily escape detection when the engine is hot, due to the rapid evaporation of coolant. Tell-tale stains of grayish white or rusty color, or dye stains from anti-freeze, at joints in cooling system are almost always sure signs of small leaks even though there appears to be no damage. Air may be drawn into the cooling system through leakage at the water pump seal or through leaks in the coolant recovery system. Gas may be forced into the cooling system through leakage at the cylinder head gasket(s) even though the leakage is not sufficient to allow coolant to enter the combustion chamber. SYSTEM CHECKS Exhaust Leaks To check for exhaust leaks into the cooling system, drain the system until the coolant level stands just above the top of the cylinder head(s), then disconnect the radiator upper hose and remove the thermostat and fan belt(s). Start the engine and quickly accelerate several times. At the same time note any appreciable coolant rise or the appearance of bubbles which are indicative of exhaust gases leaking into the cooling system. NOTICE: A defective head gasket may allow exhaust gases to leak into the cooling system. This is particu­ larly damaging to the cooling system as the gases combine with the water to form acids which are harmful to the radiator and engine. Water Pump Water pump operation may be checked by running the engine while squeezing the radiator upper hose (engine warm). A pressure surge should be felt. Check for a plugged venthole in pump. Radiator Test for restriction in the radiator, by warming the engine up and then turning the engine off and feeling the radiator. The radiator should be hot along the left side and warm along the right side, with an even temperature rise from right to left. Cold spots in the radiator indicate clogged sections. Thermostat An operational check of the thermostat can be made by hanging the thermostat on a hook in a 33% glycol solution 25°F (4°C) above the temperature stamped on the thermo­ stat valve. Submerge the valve completely and agitate the solution thoroughly. Under this condition the valve should open. Remove the thermostat and place in a 33% glycol solution 10°F (-12°C) below temperature indicated on the valve. With valve com pletely submerged and coolant agitated thoroughly, the valve should close completely. Overheat and/or Noise Engine overheat and/or cooling system noise may be caused by restrictions in the cooling system. Components which may be prone to this condition are cylinder head, water pump, block, thermostat housing and inlet manifold. Symptoms of this condition are as follows: • Engine may make snapping/cracking noises. • Heater core may gurgle or surge. • Radiator hoses may collapse and expand. • Heater hoses may vibrate and thump. • Overheat light may or may not come on. Symptoms are the result of coolant boiling at some localized area and may be noticed after extending idling and/or while being driven. Determine which side of the engine is involved and whether it is more at the front or rear of engine. Diagnosis & Inspection 1. Isolate area of engine the localized boiling is originat­ ing from. This can be done by probing engine with a sounding bar (large screw driver). 2. With radiator cap removed, observe water being circulated in radiator. Feel the front area of radiator for cold spots which indicate blockage. Blocked radia­ tors generally occur on units that have accrued miles and not on new vehicles. CAUTION:The radiator cap should be removed from a cool engine only. If the radiator cap is removed from a hot cooling system, serious per­ sonal injury may result. 3. Inspect thermostat to see if it opens completely. 4. Inspect thermostat housing to make sure it is com­ pletely free of obstructions. 5. Remove water pump from vehicle and remove the back cover on the pump. All internal passages can be inspected using a flash light. L IG H T T R U C K SERVICE M AN U AL 6B-8 ENGINE COOLING 6. Inspect cross over at the front of the inlet manifold. This entire passage can be seen with only the thermo­ stat removed. 7. Remove heads, but lay them aside for now and check the block first because the heads are the most complex pieces as far as coolant passages are concerned. 8. With water pump and heads removed, ALL coolant passages C A N be inspected by using a pen light flash light. All water jacket areas can be seen directly and a block should never be replaced as being suspect unless the restricted area can be DIRECTLY SEEN . 9. If none of the above inspections reveal the problem area, the heads must be considered prime suspect. Heads with blocked coolant passages generally have more than one area that is blocked. Inspect the heads for signs of overheat discoloration (a dark blue or black area). If none are found look in the coolant passages for blockage and probe all passages that are accessible. The head is very intricate and all passages cannot be reached. Use a probe that is fairly substantial as a tag wire may go through or around a partially blocked area. If nothing is found by visual inspection and probing, inspect the passages for a rough ragged appearance. The roughest internal passages are proba­ bly the ones that are blocked. Replace a blocked or suspect head and inspect the replacement head in the same manner before installing it. FAN CLUTCH 1 Noise Fan noise is sometimes evident under the following normal conditions: LIG H T T R U C K SE RV IC E M A N U A L • When clutch is engaged for maximum cooling. • During first few minutes after start-up until the clutch can re-distribute the silicone fluid back to its normal disengaged operating condition after over­ night settling. Fan noise or an excessive roar will generally occur continuously, however, under all high engine speed condi­ tions (2500 r.p.m. and up) if the clutch assembly is locked up due to an internal failure. If the fan cannot be rotated by hand or there is a rough grating feel as the fan is turned, the clutch should be replaced. 2. - Looseness Under various temperature conditions, there is a visible lateral movement that can be observed at the tip of the fan blade. This is a normal condition due to the type of bearing used. Approximately 1/4" (6.5m m ) maximum lateral movement measured at the fan tip is allowable. This is not cause for replacement. 3. - Silicone Fluid Leak The operation of the unit is generally not affected by small fluid leaks which may occur in the area around the bearing assembly. If the degree of leakage appears exces­ sive, however, proceed to item 4. 4. - Engine Overheating If the fan and clutch assembly free-wheels with no drag (revolves over 5 times when spun by hand), the clutch should be replaced. ENGINE COOLING 6B-9 ENGINE COOLING SYSTEM COMPLAINT TO AVO ID NEEDLESS TIME AND COST IN DIAGNOSING COOLING SYSTEM COMPLAINTS, THE CUSTOMER SHOULD BE QUESTIONED ABOUT D R IVIN G CONDITIONS THAT PLACE ABNORM AL LOADS ON THE COOLING SYSTEM. 1. DOES OVERHEATING OCCUR WHILE PULLING A TRAILER ? IF ANSWER IS "Y E S " - HOW HEAVY IS TRAILER? IF TRAILER WEIGHT IS GREATER THAN 2,000 LBS. & CAR IS EQUIPPED WITH NORMAL DUTY COOLING SYSTEM, A HEAVY DUTY COOLING PACKAGE IS REQUIRED [PER MFR'S TRAILER HAULING SPECS.). FURTHER DIAGNOSTIC CHECKS SHOULD NOT BE REQUIRED. 2. IS CAR EQUIPPED WITH A D D -O N OR AFTER MARKET AIR CONDITIONING SYSTEM? IF ANSWER IS "YES” - WAS HEAVY DUTY RADIATOR INSTALLED WITH THE SYSTEM? IF NOT, INSTALL HEAVY DUTY AIR CONDITIONING RADIATOR FOR THE CAR MODEL INVOLVED [PER MANUFACTURER'S SPECS.]. FURTHER DIAGNOSTIC CHECKS SHOULD NOT BE REQUIRED. 3. IS OVERHEATING OCCURRING AFTER PROLONGED IDLE. IN GEAR. A/C SYSTEM OPERATING? IF ANSWER IS "Y E S " - INSTRUCT OWNER ON DRIVING TECHNIQUES THAT WOULD AVO ID OVERHEATING SUCH AS: a. IDLE IN NEUTRAL AS MUCH AS POSSIBLE - INCREASE ENGINE R.P.M. TO GET HIGHER AIR FLOW & WATER FLOW THROUGH RADIATOR. b. TURN A/C SYSTEM OFF DURING EXTENDED IDLES IF OVERHEATING IS INDICATED BY HOT LIGHT OR TEMP. GAGE. FURTHER DIAGNOSTIC CHECKS SHOULD NOT BE REQUIRED. 4. IS O VERHEATING OCCURRING AFTER PROLONGED D RIVING IN SLOW CITY TRAFFIC, TRAFFIC JAMS. PARADES. ETC.? IF ANSWER IS "Y E S " - INSTRUCT OWNER ON DRIVING TECHNIQUES THAT WOULD AVO ID OVERHEATING - SAME AS FOR PROLONGED IDLES - NO. 3. FURTHER DIAGNOSTIC CHECKS SHOULD NOT BE REQUIRED. IF NONE OF THE ABOVE APPLY, GO TO DIAGNOSTIC CHART TO EFFECTIVELY USE THIS CHART, QUESTION THE OWNER TO DETERMINE WHICH OF THE FOLLOWING [3] CATEGORIES APPLIES TO THE COMPLAINT: 1. HOT LIGHT OR HOT INDICATION ON TEMPERATURE GAGE 2. BOILING 3. COOLANT LOSS 1. IF COMPLAINT IS HOT LIGHT OR HOT INDICATIO N ON TEMPERATURE GAGE WAS HOT LIGHT ACCOMPANIED BY BOILING? IF ANSWER IS "Y E S ", GO TO IF ANSWER IS "N O ", GO TO 2. IF COMPLAINT IS BOILING - GO TO B O IL IN G BOILING HOT LIGHT ON CHART ON CHART ON C H AR T 3. IF COMPLAINT IS COOLANT LOSS DETERMINE IF CUSTOMER IS O VERFILLING THE SYSTEM, THIS WOULD NORM ALLY RESULT IN SMALL AMOUNTS OF COOLANT LOSS THROUGH THE OVERFLOW TUBE. IF THIS IS THE CASE, INSTRUCT THE CUSTOMER ON PROPER F ILL LEVEL & NO FURTHER DIAGNOSTIC CHECKS SHOULD BE REQUIRED. IF OVERFILLING IS NOT THE PROBLEM, GO TO NOTICE: AN Y TIM E COOLING SYSTEM D RAIN ED AND FLUSHED. COOLANT LOSS ON CHART. IS OBVIOUSLY CONTAM INATED, THE SYSTEM SHOULD BE \> / . y • j S ( CJ X CAUTION - THE COOLING SYSTEM IS DESIGNED TO OPERATE AT 15 P.S.I. PRESSURE & TEMPERATURES EXCEEDING 200° F. CAUTION SHOULD BE EXERCISED WHEN REMOVING PRESSURE CAP OR SERVICING THE SYSTEM. . 1316 L IG H T T R U C K SERVICE M A N U A L 6B-10 CHART ENGINE COOLING DIAGNOSIS H O T L IG H T C O O L A N T LOSS B O IL IN G (or Tem p. Gage) •'ON” OR C H E C K P R E S S U R E CA P HOT TEMP C H EC K PRESSURE CAP Use Pressure Cap Tester Per C H E C K BULB Chassis Service M anual OK C H E C K S E N D IN G U N IT Use Pressure Cap Tester Per Chassis Service M anual REPLACE OK O.K. A N T I FREEZE REPLACE CHECK C O O LA N T LE V E L P R O T E C T IO N REPLACE i_fdE V IS U A L S Y S T E M C H E C K T O SPEC. YES ADD 1. L E A K S Check Hoses, R a d ia to r, Clamps, W ater Pum p, Therm ostat Housing, Rad. D ra in , S o ft or Core Plugs, Heater W ater H O T L IG H T G O TO " B O IL IN G ” OR LOW TEMP? ON C H A R T CH E C K S E N D IN G U N IT (or Tem p. Gage) ■’O N” OR HOT TEMP Valves, Heater Core. ON CAR TH E R M O S TA T CHECK J _____________________________________ * SEE T H E R M O S T A T D IA G N O S T IC C H A R T 2. F O A M IN G C O O L A N T Observe neck after engine w arm up. 3. O V E R F L O W F A N B E L T T E N S IO N T IG H T E N TO SPEC. in fille r S Y S T E M (Sem i-Sealed System) A . Check fo r Gasket in Pressure Cap. B. Check fo r Leaks • Hoses, Clam ps. O ver­ REPLACE flo w B o ttle , F ille r Neck N ipple. C. Check fo r O bstructions or Plugging in Hose Betw een R adiator and B o ttle. NO / I C O L L A P S E D UPPER OR LO W ER R A D IA T O R HOSE? SYSTEM O .K . \ J R E P A IR OR REPLA CE D E FEC TS D IR T , BU GS, B E N T F IN S . E T C . | B L O C K IN G R A D IA T O R OR A /C C O N D E N S E R ? 1 YES C L E A N OR S T R A IG H T E N PRESSURE CHECK SYSTEM Install Pressure Cap Checker on R a dia tor F ille r Neck and Pressurize I 1 1 1 System to Rated Pressure. NO I f System Does not H o ld Pressure, L po k fo r Leak Location. A N Y F IX E S A B O V E ? NO If none of the above required repair, the problem is out of the ordinary or of a m ajor nature. Listed on Sheet 3 are tw o groups o f p roblem areas th at should be checked in the order listed. R E P A IR ENGINE COOLING 6B-11 ON VEHICLE SERVICE WATER PUMP Removal - L6 1. 2. 3. 4. Disconnect battery negative cable at battery. Drain cooling system. Remove accessory drive belts. Remove fan to water pump hub (or fan clutch to water pump hub) attaching bolts (or nuts) and remove fan and pulley. 5. Remove lower radiator hose and heater hose from water pump. 6. Remove water pump to block attaching bolts and remove water pump. • On some vehicles, the generator adjusting brace is retained by one of the water pump to block bolts. If necessary, loosen generator adjusting bolt to allow this brace to be moved away from pump to prevent removal interference. Installation - L6 1. With clean sealing surfaces on both water pump and block, place new gasket on water pump, mount on block and retain with attaching bolts. Torque bolts to 15 lb. ft. (20 N-m). • If generator adjusting brace was moved, move to original position before torquing water pump bolts. 2. Install lower radiator hose and heater hose to pump. 3. Install water pump pulley and fan (or fan clutch assem bly) on water pump hub. Torque retaining fasteners to 30 N-m (25 N-m if engine has fan clutch assembly). 4. Install accessory drive belts and adjust to specifications. 5. Connect battery negative cable. 6. Fill cooling system with an ethylene glycol anti-freeze and water mixture of 50/50%. 7. Start engine and run, with radiator cap removed, until radiator upper hose becomes hot (thermostat open). 8. With engine idling, add coolant taradiator until level reaches bottom of filler neck. 9. Install cap, making sure arrows line up with overflow tube. Removal - V8 1. 2. 3. 4. 5. 6. 7. 8. Disconnect battery negative cable at battery. Drain cooling system. Remove accessory drive belts. Remov^fan to water pump hub (or fan clutch to water pump hub) attaching bolts (or nuts) and remove fan and pulley. Remove generator lower brace to water pump attach­ ing bolts and swing brace down and out of way. Remove generator upper brace to water pump attach­ ing bolts. Remove lower radiator hose and heater hose from water pump. On 7.4 liter engine, remove by-pass hose. Remove water pump to block attaching bolts and remove pump. Installation - V8 If installing new water pump, transfer heater hose fitting from old unit. On 7.4 liter engine, also transfer by­ pass fitting. 1. With clean sealing surfaces on both water pump and block, place a 1/8 " (3mm) bead of RTV, # 1052366 or equivalent, along the sealing edge of each water pump leg. Place pump against block and retain with attaching bolts. Torque bolts to 20 N-m. 2. Attach lower radiator hose and heater hose to water pump. On 7.4 liter engine, install by-pass hose. 3. Attach generator upper and lower braces to water pump. Torque bolts to 35 N-m. 4. Install water pump pulley and fan (or fan clutch) to water pump hub. Torque fasteners to 30 N-m. 5. Install accessory drive belts. Adjust to specifications. 6. Connect battery negative cable. 7. Fill cooling system with an ethylene glycol anti-freeze and water mixture of 50/50%. 8. Start engine and run, with radiator cap removed, until radiator upper hose becomes hot (thermostat open). 9. With engine idling, add coolant to radiator until level reaches bottom of filler neck. 10. Install cap, making sure arrows line up with overflow tube. Removal - Diesel 1. Drain radiator. 2. Disconnect lower radiator hose at water pump. 3. Disconnect heater hose and by-pass hose at water pump. 4. Remove fan assembly. 5. Remove all pulley belts. 6. Remove water pump pulley. 7. Disconnect generator, P /S pump bracket and, if equipped, A /C compressor bracket. 8. Remove water pump attaching bolts and water pump. Installation - Diesel 1. Transfer studs to new water pump, if applicable. 2. Clean gasket material from engine block. 3. Apply a thin coat of # 1050026 sealer, or equivalent, to the water pump housing to retain gasket, then position new gasket on housing. 4. Reverse removal procedure. 5. Adjust belts to specifications. 6. Refill cooling system. THERMOSTAT Removal (All Engines) 1. Disconnect battery negative cable at battery. 2. Drain cooling system until radiator coolant level is below thermostat. 3. Remove water outlet attaching bolts and remove outlet. Remove thermostat. LIG H T T R U C K SERVICE M AN U AL 6B-12 ENGINE COOLING Installation (All Engines) Prior to installing thermostat, make sure thermostat housing and coolant outlet sealing surfaces are clean. 1. Place a 1/8" (3mm) bead of RTV sealer, # 1 0 5 2 3 6 6 or equivalent, all around the coolant outlet sealing surface on the thermostat housing. 2. Place thermostat in housing. 3. Install coolant outlet while RTV is still wet. Torque retaining bolts to 20 lb. ft. (27 N-m). 4. Connect battery negative cable. 5. Fill cooling system with an ethylene glycol anti-freeze and water mixture of 50/50%. 6. Start engine and run, with radiator cap removed, until radiator upper hose becomes hot (thermostat open). 7. With engine idling, add coolant to radiator until level reaches bottom of filler neck. 8. Install cap, making sure arrows line up with overflow tube. RADIATOR (FIG. 6B-6 THRU 6B-9) 5. Connect battery negative cable. 6. Fill cooling system with an ethylene glycol anti-freeze and water mixture of 50/50%. 7. Start engine and run, with radiator cap removed, until radiator upper hose beocmes hot (thermostat open). 8. With engine idling, add coolant to radiator until level reaches bottom of filler neck. 9. Install cap, making sure arrows line up with overflow tube. FAN SHROUD (FIG. 6B-10 THRU 6B-12) Removal (CK Series) 1. Disconnect battery negative cable. 2. Remove fan shroud to radiator retainer attaching screws. 3. Remove fan clutch to water pump hub attachments. 4. Remove shroud by pulling up and out of lower retaining clips. Fan shroud and fan clutch assembly must be removed together. Installation (CK Series) Removal (G & CK Series) 1. 2. 3. 4. 5. 6. Disconnect battery negative cable at battery. Drain cooling system. Remove radiator hoses from radiator. Remove overflow hose from radiator. Remove fan shroud. Remove radiator to radiator support retainers (upper mounting panel on "CK ") and remove radiator. Installation 1. Place radiator in vehicle and install radiator to radiator support retainers. 2. Install fan shroud. 3. Connect overflow hose to radiator. 4. Connect radiator hoses to radiator. 1. Lower fan shroud and fan clutch along back of radia­ tor. Make sure lower edge fits into lower retaining clips. 2. Install fan clutch to water pump attachm ents and torque to 27 N-m. 3. Install shroud to radiator retainer attaching screws. Torque to 6 N-m. 4. Connect battery negative cable. Removal ( "G" Series-V8 Engines) 1. 2. 3. 4. 5. 6. Disconnect battery negative cable. If A /C equipped, remove vacuum reservoir. Remove windshield washer jar and bracket. Remove shroud retaining screws. Remove radiator support bracket. Remove dip stick from engine (transmission also if equipped with automatic). 7. Remove radiator hose strap from shroud. 8. Remove fan shroud from water pump (leave pulley), then remove fan and shroud together. Installation ( " G" Series-V8 Engines) 1. Install fan and shroud together then, attach fan to water pump. 2. Attach radiator hose strap to shroud. 3. Install dipstick in engine and, where applicable, in transmission. 4. Install radiator support bracket. 5. Install shroud retaining screws. 6. Install windshield washer jar and bracket. 7. If equipped with A /C , install vacuum reservoir. 8. Connect battery cable. FAN/FAN CLUTCH Removal (All) 1. Remove battery negative cable at battery. 2. Remove radiator fan shroud as required. LIG H T T R U C K SE RV IC E M AN U AL ENGINE COOLING 6B-13 CK 2 0 0 -3 0 0 5.7 AUTO-ALL CK-100 5 .0 -5 .7 AUTO W / A / C OR H.D. COO LING 6.6-7.4-ALL 5.7-DIESEL-ALL 5 .0 -5 .7-M AN.-ALL CK-100 5 .0 -5 .7-AUTO W / O A /C OR H.D. COOLING 4.1-4.8-ALL W / A / C 4.1-4.8-ALL W / O A /C Fig. 6B-7--'CK' Radiator Mounting RADIATOR. SUPPORT RADIATOR SUPPORT BRACE P000(42) RADIATOR ASM 0 m Mounting location fo r L25 &M15 or M20. RADIATOR Mounting location fo r L25 &M38 or M40; &LS9. W /L F 8 EXC. LF8 Fig. 6B-8--'P' (42) R adiator Mounting 3. Remove fan clutch hub-to-water pump hub attaching bolts or nuts, as applicable, and remove fan clutch assembly. 4. Remove fan from fan clutch hub. Installation (All) CAUTION:lf a fan blade is bent or damaged in any way, no attempt should be made to repair and/or reuse the damaged part. A bent or dam­ aged fan assembly should always be replaced with a new fan assembly. It is essential that the fan assembly remain in proper balance. Balance cannot be assured once a fan assembly has been bent or damaged. A fan assembly that is not in proper balance could fail and fly apart during subsequent use, creating an extremely dangerous condition. All mating surfaces (water pump hub and fan clutch hub) should be inspected for smoothness and reworked as necessary to eliminate burrs or other imperfections. 1. With fan on fan clutch hub, install fan clutch assembly to water pump hub. Torque attaching bolts, or nuts, to 20 lb. ft. (27 N-m). Be sure to align reference marks on both hubs. 2. Install radiator shroud as required. 3. Connect battery negative cable. COOLANT RECOVERY BOTTLE (FIG. 6B-13 & 6B14) Removal 1. Disconnect battery negative cable. 2. Remove coolant overflow hose from recovery bottle. 3. Remove recovery bottle retaining fasteners and remove bottle from vehicle. LIG H T T R U C K SERVICE M AN U AL 6B-14 ENGINE COOLING STUD B R AKE C YL SUPPORT VIEW [z ] [^ C A U T IO N ] Radiator Support Asm is not a structural member. No Body Mtg Supports o r other attachments used fo r structural purposes are to be fastened to Radiator Support Asm. Upper & lo w e r ra d ia to r su p p orts must be in sta lle d w ith studs in fo rw a rd p o s itio n . Fig. 6B-9--'P' (32) Radiator Mounting In sta lla tio n When installing coolant recovery bottle, make sure unit is clean and free from contamination. If needed, wash bottle with soap and water. Rinse thoroughly. 1. Install bottle in vehicle and retain with appropriate fasteners. 2. Connect coolant overflow hose to recovery bottle. 3. Fill recovery bottle to appropriate mark with a 50/50 solution of water and ethlyne glycol base anti-freeze. 4. Connect battery cable. ENGINE OIL COOLER All truck vehicle lines have available, as either stan­ dard or optional equipment, oil coolers for the engine oil. For the location of these units, refer to figures 6B -15 & 6B -16. Fig. 6 B -1 0 --"G " Van Fan Shroud LIG H T TR U C K SE RV IC E M AN U AL ENGINE COOLING 6B-15 RADIATOR M O U N T IN G PANEL RADIATOR SUPPORT 5 .0 /5 .7 RADIATOR SUPPORT WITH 7 .4 OR 5.7 DIESEL RADIATOR M O U N TIN G PANEL jV IE W |VIEW A &LE3 OR L25 Fig. 6B-11--"CK" Series Fan Shroud M O T O R H O M E C H A S S IS P (3 2 ) Fig. 6B-12--"P" Series Fan Shroud LIG H T T R U C K SERVICE M AN U AL 6B-16 ENGINE COOLING LIG H T TR U C K SE RV IC E M A N U A L S T R U T ROD ENG INE MTG B R K T CO O LER / / / R ETU R N HOSE / SUPPLY HOSE A D A P T ASM Fig. 6B-16--Engine Oil Coolers Except LF9 ENGINE COOLING 'G ' V A N 6B-17 ENGINE FUEL 6C-1 SECTION 6C ENGINE FUEL CONTENTS General... Diagnosis Model 1ME Carburetor Model 2SE Carburetor 6C-1 6C-1 6C1- 1 6C2- 1 Model M 2M E Carburetor Model M4M Carburetor Fuel System 6C3- 1 6C4- 1 6C5- 1 GENERAL ALL N EW GM VEHICLES ARE CERTIFIED BY THE U N ITED ST A T E S E N V IR O N M E N T A L PRO TECTIO N A G E N C Y A S C O N ­ FO RM ING TO THE R EQ U IR EM EN TS OF THE REG U LATIO NS FOR THE CONTROL OF AIR POLLUTION FROM N EW MOTOR VEHICLES. THIS CERTIFICATION IS C O N T IN G E N T O N CER­ T A IN A D JU ST M E N T S BEING SET TO FACTORY ST A N D A R D S. IN M OST C A SE S, TH ESE A D JU ST M E N T PO IN T S EITH ER HAVE BEEN PE R M A N E N T L Y SEALED A N D /O R MADE INA CCESSIBLE TO PREVENT IN D ISC R IM IN A T E OR ROUTINE A D JU ST M E N T IN THE FIELD. FOR THIS REA SO N , THE FACTORY PROCEDURE FOR TEM PORARILY REM OVING PLUGS, CAP, ETC., FOR PU R ­ POSES OF SE R V IC IN G THE PR O D U C T, M U ST BE STR IC TLY FOLLOW ED A N D , W HEREVER PRACTICABLE, R E T U R N E D TO THE O R IG IN A L IN TEN T OF THE DESIGN. This section, divided into sub-sections by carburetor model, covers the repair and adjustment procedure for fuel system components. Typical illustrations and procedures are used except where specific illustrations or procedures are necessary to clarify the operation. NOTICE: All engines require the use of unleaded fuel only. Use of leaded and/or low lead fuel can result in engine damage and reduce the effectiveness of the Emission Control Systems. LIG H T T R U C K SERVICE M A N U A L 6C-2 ENGINE FUEL CARBURETOR DIAGNOSIS T h e fo llo w in g d ia g n o s tic p ro c e d u re s are f o r c a r b u re to r re la te d p ro b le m s a n d th e ir e ffe c ts o n c a r p e rfo rm a n c e . O th e r syste m s o f th e c a r can also cause s im ila r p ro b le m s a n d s h o u ld be c h e c k e d w h e n lis te d o n th e c h a r t. T h e p r o b le m areas d e s c rib e d are: 1. E n g in e c ra n k s n o r m a lly . W ill n o t s ta rt. 2. E n g in e s ta rts a n d sta lls . 3. E n g in e s ta rts h a rd . 4. E n g in e id le s a b n o rm a lly a n d / o r sta lls. 5. In c o n s is te n t e n g in e id le speeds. 6. E n g in e die se ls (a fte r- ru n ) u p o n s h u t o f f . 7. E n g in e h e sita te s o n a c c e le ra tio n . 8. E n g in e has less th a n n o rm a l p o w e r a t lo w speeds. 9. E n g in e has less th a n n o rm a l p o w e r o n h e a vy a c c e le ra tio n o r a t h ig h speed. 10. E n g in e surges. 11. P o o r gas m ile a ge . C O N D I T IO N E n g in e C ra n k s N o r m a lly P O S S IB L E C A U S E Im p r o p e r s ta rtin g p ro c e d u re used. - W ill N o t S ta r t. C O R R E C T IO N C h e c k w it h th e c u s to m e r t o d e te rm in e if p r o p e r s ta rtin g p ro c e d u re is used, as o u t lin e d in th e O w n e r's M a n u a l. C h o k e va lve n o t o p e ra tin g p r o p e r ly . A d ju s t th e c h o k e th e r m o s ta tic c o il to s p e c ific a tio n . C h e c k th e c h o k e va lv e a n d /o r lin k a g e as nece ssa ry. R e p la c e p a rts i f d e fe c tiv e . I f caused b y fo re ig n m a te ria l a n d g u m , clea n w it h s u ita b le n o n - o il base s o lv e n t. N O T E : A f t e r a n y c h o k e s y s te m w o r k , c h e c k c h o k e v a c u u m b re a k s e ttin g s a n d c o r r e c t as necessary. N o fu e l in c a rb u re to r . R e m o v e fu e l lin e a t c a r b u r e to r . C o n n e c t hose to fu e l lin e a n d ru n in t o m e ta l c o n ta in e r . R e m o v e th e w ir e fr o m th e " b a t " te r m in a l o f th e d is t r ib u t o r . C ra n k o v e r e n g in e — i f th e re is n o fu e l d is ­ ch arg e f r o m th e fu e l lin e , te s t fu e l p u m p as o u t lin e d in S e c tio n 6 . I f fu e l s u p p ly is o k a y , c h e c k th e f o llo w in g : a. In s p e c t fu e l in le t f il t e r . I f p lu g g e d , re p la c e . b . I f fu e l f i l t e r is o k a y , re m o v e a ir h o rn a nd c h e c k f o r a b in d in th e f lo a t m e c h a n is m o r a s tic k in g in le t n e e d le . I f o k a y , a d ju s t f lo a t as s p e c ifie d . E n g in e flo o d e d . T o c h e c k R e m o v e th e a ir h o r n . f o r flo o d in g , re m o v e th e a ir cle a n e r w it h th e e n g in e C h e c k fu e l in le t n e e d le a n d seat f o r im m e d ia te ly s h u t o f f a nd p r o p e r seal. I f a n e e d le a n d seat lo o k in t o th e c a rb u r e to r te s te r is n o t a v a ila b le , a p p ly v a c u u m b ore s. F uel w il l be d r ip p in g to th e n e e d le seat w it h n e e d le in s ta lle d . o f f n o zzle s. I f th e n e e d le is le a k in g , re p la c e . C h e c k f lo a t f o r fre e m o v e m e n t, b e n t f lo a t h a n g e r o r b in d s in th e f lo a t a rm . I f fo r e ig n m a te ria l is in fu e l s y s te m , cle a n th e s y s te m a nd re p la c e fu e l filt e r s as n ece ssa ry. I f e xcessive fo r e ig n m a te ria l is fo u n d , c o m p le te ly d is a s s e m b le a n d c le a n . Fig. 6C-1--Diagnosis 1 of 8 LIG H T T R U C K SERVICE M A N U A L ENGINE FUEL 6C-3 CARBURETOR DIAGNOSIS CONT'D. CONDITION E n g in e S ta rts — W ill CORRECTION POSSIBLE CAUSE C h e c k fu e l p u m p p re ssu re a n d v o lu m e , re p la c e Fuel pum p. i f n e ce ssa ry. See F U E L S Y S T E M D IA G N O S IS , N o t K e e p R u n n in g S e c tio n 6 . Id le speed. A d ju s t id le t o s p e c ific a tio n s . C h o k e h e a te r s y s te m m a l­ C h e c k v a c u u m s u p p ly a t h o t a ir in le t f u n c tio n in g (m a y cause t o c h o k e h o u s in g . S h o u ld be n o t less th a n m a n ifo ld v a c u u m m in u s 3 " H g. w it h lo a d in g ). e n g in e r u n n in g a t id le . (E x c . IM V ) C h e c k w ir in g . C h e c k f o r p lu g g e d , r e s tr ic te d , o r b ro k e n h e a t tu b e s . C h e c k r o u t in g o f a ll h o t a ir p a rts . L o o s e , b ro k e n o r in c o r r e c t C h e c k c o n d itio n a n d r o u t in g o f all v a c u u m hose r o u tin g . v a c u u m hoses — c o r r e c t as necessary. E n g in e doe s n o t have C h e c k f o r fre e m o v e m e n t o f fa s t e n o u g h fa s t id le speed id le c a m . C le a n a n d / o r re a lig n as w h e n c o ld . n ece ssa ry. C h o k e v a c u u m b re a k u n its A d ju s t b o th v a c u u m b re a k assem blies are n o t a d ju s te d to to s p e c ific a tio n . I f a d ju s te d o k a y , s p e c ific a tio n o r are c h e c k th e v a c u u m b re a k u n its f o r p ro p e r d e fe c tiv e . o p e r a tio n as fo llo w s : T o c h e c k th e v a c u u m b re a k u n its , a p p ly a c o n s ta n t v a c u u m s o u rc e o f a t least 1 0 " H g ., p lu n g e rs s h o u ld s lo w ly m o ve in w a rd a n d h o ld v a c u u m . I f n o t , re pla ce th e u n it . A lw a y s c h e c k th e fa s t id le ca m a d ju s tm e n t w h e n a d ju s tin g v a c u u m b re a k u n its . C h o k e va lve s tic k in g a n d / o r b in d in g . C le a n a n d a lig n lin k a g e o r re pla ce i f n e ce ssa ry. R e a d ju s t a ll c h o k e s e ttin g s , see S e c tio n 6 M , i f p a r t re p la c e m e n t o r re a lig n m e n t is necessary. I n s u ffic ie n t fu e l in C h e c k fu e l p u m p p ressure a nd v o lu m e . C a rb u re to r. C h e c k f o r p a r t ia lly p lu g g e d fu e l in le t f il t e r . R e p la c e if c o n ta m in a te d . C h e c k th e f l o a t level a d ju s tm e n t f o r b in d in g c o n d itio n . A d ju s t as s p e c ifie d . E n g in e S ta rts H a rd L o o s e , b ro k e n o r in c o r r e c t C h e c k c o n d itio n a nd r o u tin g o f (C ra n k s N o r m a lly ) v a c u u m hose r o u tin g . a ll v a c u u m hoses — c o r r e c t as nece ssa ry. See S e c tio n 6 E . I n c o r r e c t s ta r tin g p ro c e d u re . C h e c k t o be sure c u s to m e r is usin g th e s ta r tin g p ro c e d u re o u t lin e d in O w n e r 's M a n u a l. Fig. 6C-2--Diagnosis 2 of 8 LIG H T T R U C K SERVICE M A N U A L 6C-4 ENGINE FUEL CARBURETOR DIAGNOSIS CONT'D. CONDITION POSSIBLE CAUSE CORRECTION E n g in e S ta rts H a rd M a lf u n c t io n in a c c e le ra to r C h e c k a c c e le ra to r p u m p a d ju s tm e n t (C ra n k s N o r m a lly ) p u m p s y s te m . an d o p e r a tio n . (C o n tin u e d ) C h e c k p u m p d is c h a rg e b a ll f o r s tic k in g o r leakage. C h o k e v a lv e n o t c lo s in g . A d ju s t c h o k e th e r m o s ta tic c o il. C h e c k c h o k e v a lv e a nd lin k a g e f o r b in d s a n d a lig n m e n t. C le a n a nd re p a ir o r re p la c e as necessary. V a c u u m b re a k s m is a d ju s te d C h e c k f o r a d ju s tm e n t a n d fu n c tio n o f o r m a lfu n c tio n in g . v a c u u m b re a k s . C o r r e c t as necessary. In s u ffic ie n t fu e l in b o w l. C h e c k fu e l p u m p p ressu re a n d v o lu m e . C h e c k f o r p a r t ia lly p lu g g e d fu e l in le t f il t e r . R e p la c e i f d ir t y . C h e c k f lo a t m e c h a n is m . A d ju s t as s p e c ifie d . F lo o d in g . C h e c k f lo a t a nd n e e d le a n d seat f o r p r o p e r o p e r a tio n . S lo w e n g in e c ra n k in g speed. R e fe r to s ta r tin g c ir c u it d ia g n o s is . S e c tio n 6 D . E n g in e Id le s A b n o r m a lly In c o r r e c t id le speed. (T o o fa s t o r to o s lo w ) R ese t id le speed p e r in s tr u c tio n s o n u n d e r h o o d la b e l. A i r leaks in t o c a rb u r e to r C h e c k a ll v a c u u m hoses a nd re s tr ic to r s b o re s b e n e a th t h r o t t le valve s, le a d in g in t o th e m a n ifo ld o r c a r b u r e to r m a n ifo ld lea ks, o r v a c u u m base f o r leaks o r b e in g d is c o n n e c te d . hoses d is c o n n e c te d o r in ­ In s ta ll o r re pla ce as nece ssa ry. s ta lle d im p r o p e r ly . T o r q u e c a r b u r e to r to m a n ifo ld b o lts to 10 f t . lbs. U s in g a p re ssu re o il c a n , s p ra y lig h t o il o r ke ro s e n e a ro u n d m a n ifo ld to head su rfa ce s a n d c a r b u r e to r t h r o t t le b o d y . N O T E : D o n o t s p ra y a t t h r o t t l e s h a ft end s. I f e n g in e R P M ch an g e s, tig h te n o r re ­ p la ce th e c a r b u r e to r o r m a n ifo ld gas­ k e ts as necessary. C lo g g e d o r m a lf u n c t io n in g C h e c k P C V s y s te m . C le a n a n d / o r re p la c e P C V syste m . as necessary. C a rb u r e to r flo o d in g . R e m o v e a ir h o rn a n d c h e c k f lo a t a d ju s tm e n ts . C h e c k b y u s in g p ro c e d u re o u t lin e d u n d e r " E n g in e C h e c k f lo a t n e e d le a n d seat f o r p r o p e r Flooded". seal. I f a n ee d le a n d seat te s te r is n o t a v a ila b le , a p p ly v a c u u m t o th e n e e d le seat w it h n ee d le in s ta lle d . I f th e n e e d le is le a k in g o r d a m a g e d , re p la c e . Fig. 6C-3--Diagnosis 3 of 8 LIG H T T R U C K SERVIC E M A N U A L ENGINE FUEL 6C-5 CARBURETOR DIAGNOSIS CONT'D. CONDITION CORRECTION POSSIBLE CAUSE E n g in e Id le s A b n o r m a lly C h e c k f lo a t f o r fre e m o v e m e n t. (T o o fa s t o r to o s lo w ) C h e c k f o r b e n t f l o a t h a n g e r o r b in d s ( C o n tin u e d ) in th e f l o a t a rm . I f fo r e ig n m a te r ia l is fo u n d in th e c a r b u r e to r , c le a n th e fu e l s y s te m a nd c a r b u r e to r . R e p la c e fu e l f i l t e r as n e ce ssa ry. R e s tric te d a ir c le a n e r e le m e n t. R e p la c e as nece ssa ry. Id le s y s te m p lu g g e d C le a n c a r b u r e to r , see S e c tio n 6 C 1 . o r re s tric te d . In c o r r e c t id le m ix tu r e R e a d ju s t p e r s p e c ifie d p ro c e d u re . See a d ju s tm e n t. S e c tio n 6 C 1 . D e fe c tiv e id le s to p s o le n o id , C h e c k s o le n o id a n d w ir in g . id le sp e e d -u p s o le n o id o r w ir in g . T h r o t t le b la d e s o r lin k a g e C h e c k t h r o t t l e lin k a g e a n d t h r o t t le s tic k in g a n d / o r b in d in g . b la d e s ( p r im a r y a n d s e c o n d a ry ) f o r s m o o th a n d fre e o p e r a tio n . C o r r e c t p r o b le m areas. E n g in e D iesels ( A ft e r L o o s e , b ro k e n o r im p r o p e r ly C h e c k c o n d itio n a n d r o u t in g o f all R u n ) u p o n S h u t O ff ro u te d v a c u u m hoses. v a c u u m hoses. C o r r e c t as necessary. In c o rr e c t id le speed. R ese t id le speed p e r in s tr u c tio n s o n la b e l in e n g in e c o m p a r tm e n t. M a lf u n c t io n o f id le s to p C h e c k f o r c o r r e c t o p e r a tio n o f id le s o le n o id , id le s p e e d -u p s o le n o id . C h e c k f o r s tic k y o r b in d in g s o le n o id o r d a s h p o t. s o le n o id . F a st id le ca m n o t f u l ly o f f . C h e c k fa s t id le c a m f o r fr e e d o m o f o p e r a tio n . C le a n , re p a ir, o r a d ju s t as r e q u ir e d . C h e c k c h o k e h e a te d a ir tu b e s f o r r o u t in g , f it t in g s b e in g t ig h t o r tu b e s p lu g g e d . C h e c k c h o k e lin k a g e f o r b in d in g . C le a n a nd c o r r e c t as nece ssa ry. E x c e s s iv e ly lean c o n d itio n A d ju s t c a r b u r e to r id le m ix tu r e as caused b y m a la d ju s te d c a r­ d e s c rib e d in S e c tio n 6 C 1 . b u r e t o r id le m ix tu r e . Ig n it io n tim in g re ta rd e d . S e t to s p e c ific a tio n s . E n g in e H e s ita te s O n L o o s e , b ro k e n o r in c o r r e c t C h e c k c o n d itio n a n d r o u tin g o f a ll v a c u u m A c c e le r a tio n v a c u u m hose r o u tin g hoses — c o r r e c t o r re p la c e . A c c e le r a to r p u m p n o t a d ju s te d A d ju s t a c c e le ra to r p u m p , re p la c e . t o s p e c ific a tio n o r in o p e r a tiv e . In o p e r a tiv e a c c e le ra to r p u m p R e m o v e a ir h o r n a nd c h e c k p u m p c u p . I f c ra c k e d , s c o re d o r d is t o r t e d , re ­ sy s te m . p la c e th e p u m p p lu n g e r. Fig. 6C-4--Diagnosis 4 of 8 L IG H T T R U C K SERVICE M AN U AL 6C-6 ENGINE FUEL CARBURETOR DIAGNOSIS CONT'D. CONDITION POSSIBLE CAUSE CORRECTION E n g in e H e s ita te s O n N O T E : A q u ic k c h e c k o f th e C h e c k th e p u m p d is c h a rg e b a ll f o r A c c e le ra tio n p u m p sy s te m can be m a de as p ro p e r s e a tin g a n d lo c a tio n . ( C o n tin u e d ) fo llo w s : W ith th e e n g in e o f f , lo o k in t o th e c a r b u r e to r b o re s a n d o b se rve p u m p n o z z le s w h ile q u ic k ly o p e n in g t h r o t t le le ve r. A f u ll s tre a m o f fu e l s h o u ld e m it f r o m each p u m p n o z z le . F o re ig n m a tte r in p u m p passages. C le a n a n d b lo w o u t w it h c o m p re s s e d a ir. F lo a t leve l to o lo w . C h e c k a nd re set f l o a t le v e l to s p e c ific a tio n . F r o n t v a c u u m b re a k d ia p h ra g m C h e c k a d ju s tm e n t a n d o p e r a tio n o f n o t f u n c tio n in g p r o p e r ly . v a c u u m b re a k d ia p h ra g m . A i r va lve m a lfu n c tio n . C h e c k o p e r a tio n o f s e c o n d a ry a ir va lv e . C h e c k s p rin g te n s io n a d ju s tm e n t. P o w e r e n r ic h m e n t s y s te m n o t C h e c k f o r b in d in g o r s tu c k p o w e r o p e ra tin g c o r r e c t ly . p is to n (s ) — c o r r e c t as nece ssa ry. In o p e ra tiv e a ir c le a n e r h ea ted C h e c k o p e r a tio n o f th e r m o s t a tic a ir a ir c o n t r o l. c le a n e r s y s te m . F u e l f i l t e r d ir t y o r p lu g g e d . R e p la c e f i l t e r a nd clea n fu e l s y s te m as necessary. D is t r ib u t o r v a c u u m o r m e c h a n ic a l C h e c k f o r p r o p e r o p e r a tio n . ad va n ce m a lfu n c tio n in g . T im in g n o t to s p e c ific a tio n s . A d ju s t to s p e c ific a tio n s . C h o k e c o il m is a d ju s te d (c o ld A d ju s t t o s p e c ific a tio n s . o p e ra tio n .) E G R v a lve s tu c k o p e n . In s p e c t a nd cle a n E G R v a lv e . E n g in e Has Less T h a n L o o s e , b ro k e n o r in c o r r e c t C h e c k c o n d itio n a nd r o u t in g o f a ll N o rm a l P o w e r A t N o rm a l v a c u u m hose r o u tin g . v a c u u m hoses. C lo g g ed o r d e fe c tiv e P C V s y s te m . C le a n o r re p la c e as n e ce ssa ry. C h o k e s tic k in g . C h e c k c o m p le te c h o k e s y s te m f o r s tic k in g A c c e le ra tio n s . o r b in d in g . C le a n a n d re a lig n as n ece ssa ry. C h e c k a d ju s tm e n t o f c h o k e th e r m o s ta tic c o il. C h e c k c o n n e c tio n s a n d o p e r a tio n o f c h o k e h o t a ir s y s te m . C h e c k je ts a n d c h a n n e ls f o r p lu g g in g ; c le a n a n d b lo w o u t passages. C lo g g e d o r in o p e ra tiv e p o w e r R e m o v e a ir h o rn a nd c h e c k f o r fre e syste m . o p e r a tio n o f p o w e r p is to n s . Fig. 6C-5-Diagnosis 5 of 8 L IG H T T R U C K SERVICE M A N U A L ENGINE FUEL 6C-7 CARBURETOR DIAGNOSIS CONT'D. CORRECTION POSSIBLE CAUSE CONDITION E n g in e Has Less T h a n A i r c le a n e r te m p e ra tu r e reg­ C h e c k r e g u la tio n a n d o p e r a tio n o f N o rm a l P o w e r A t N o rm a l u la tio n im p ro p e r. a ir c le a n e r s y s te m . T ra n s m is s io n m a lf u n c t io n . R e fe r t o tra n s m is s io n d ia g n o s is . Ig n it io n s y s te m m a lf u n c t io n . C h e c k ig n itio n s y s te m . See S e c tio n 6 D . A c c e le ra tio n s . (C o n tin u e d ) R e fe r t o H .E .l. d ia g n o s is . E x h a u s t s y s te m . C h e c k f o r r e s tr ic tio n s . C o r r e c t as re q u ire d . Less T h a n N o rm a l P o w e r C a r b u r e to r t h r o t t l e valves C o r r e c t t h r o t t l e lin k a g e to o b ta in O n H e a v y A c c e le ra tio n n o t g o in g w id e o p e n . T u r n o f f w id e o p e n t h r o t t l e in c a r b u r e to r . O r A t H ig h Speed e n g in e a n d c h e c k b y p u s h in g a c c e le ra to r p e d a l to f lo o r . S e c o n d a ry t h r o t t le lo c k o u t n o t a llo w in g s e c o n d a rie s to C h e c k f o r b in d in g o r s tic k in g lo c k o u t le v e r. open. C h e c k f o r fre e m o v e m e n t o f fa s t id le ca m . C h e c k c h o k e h e a te d a ir s y s te m f o r p ro p e r a n d t i g h t c o n n e c tio n s p lu s f lo w th r o u g h s y s te m . C h e c k a d ju s tm e n t o f c h o k e th e r m o s ta tic c o il. M a k e nece ssa ry c o r r e c tio n s a nd a d ju s tm e n ts . S p a rk p lu g s fo u le d , in c o r r e c t C le a n , re g a p , o r re p la c e p lu g s. gap. P lug g e d a ir c le a n e r e le m e n t. R e p la c e e le m e n t. A i r va lve m a lf u n c t io n . C h e c k f o r fre e o p e r a tio n o f a ir v a lve . (W h e re a p p lic a b le ) C h e c k s p rin g te n s io n a d ju s tm e n t. M a k e n ecessary a d ju s tm e n ts a n d c o r r e c tio n s . P lu g g e d fu e l in le t f ilt e r . R e p la c e w it h a n e w f i l t e r e le m e n t. In s u ffic ie n t fu e l to c a r b u r e to r . C h e c k fu e l p u m p a nd s y s te m , ru n p ressu re a nd v o lu m e te s t. See F U E L S Y S T E M D IA G N O S IS , S e c tio n 6 . P o w e r e n r ic h m e n t s y s te m R e m o v e th e a ir h o r n a n d c h e c k f o r fre e n o t o p e ra tin g c o r r e c t ly . o p e r a tio n o f b o th p o w e r p is to n ( s ) , clea n a n d c o r r e c t as n ece ssa ry. C h o k e clo se d o r p a r t ia lly F re e c h o k e v a lv e o r lin k a g e . c lo s e d . C h e c k f o r lo o se je ts . F lo a t level t o o lo w . C h e c k a n d re set f lo a t level to s p e c ific a tio n . Fig. 6C-6--Diagnosis 6 of 8 LIG H T T R U C K SERVICE M A N U A L 6C-8 ENGINE FUEL CARBURETOR DIAGNOSIS CONT'D. CONDITION Less T h a n N o rm a l P o w e r POSSIBLE CAUSE CORRECTION T ra n s m is s io n m a lf u n c t io n . R e fe r to tra n s m is s io n d ia g n o s is . I g n it io n s y s te m m a lf u n c t io n . C h e c k ig n itio n s y s te m . See S e c tio n 6 D . O n H e a v y A c c e le ra tio n O r A t H ig h Speed (C o n tin u e d ) F u e l m e te rin g je ts re s tric te d . I f th e fu e l m e te rin g je ts are r e s tric te d and an excessive amount of foreign material is found in th e fu e l b o w l, th e c a r b u r e to r s h o u ld be c o m p le te ly d is a s s e m b le d a nd c le a n e d . Fuel p u m p . C h e c k fu e l p u m p p ressu re a n d v o lu m e , in s p e c t lin e s f o r leaks a nd r e s tr ic tio n s . See F U E L S Y S T E M D IA G N O S IS , S e c tio n 6. E x h a u s t s y s te m . C h e c k f o r r e s tr ic tio n s . C o r r e c t as required. E n g in e Surges L o o s e , b r o k e n o r in c o r r e c t C h e c k c o n d itio n a n d r o u t in g o f all v a c u u m hose r o u tin g . v a c u u m hoses. C o r r e c t as nece ssa ry. P C V s y s te m clo g g e d o r C h e c k P C V s y s te m . C le a n o r re p la c e m a lf u n c t io n in g . as necessary. Lo o se c a r b u r e to r , E G R o r in ta k e T o r q u e c a r b u r e to r to m a n ifo ld b o lts m a n ifo ld b o lts a n d /o r le a k in g t o 10 f t . lbs. U s in g a p re ssu re o il gaskets. c a n , s p ra y lig h t o il o r ke ro s e n e a ro u n d m a n ifo ld t o hea d m o u n tin g s u r­ fa c e a nd c a r b u r e to r base. I f e n g in e R P M changes, tig h te n o r re p la c e th e c a r­ b u r e t o r o r m a n ifo ld g aske ts as necessary. C h e c k E G R m o u n tin g b o l t to r q u e . L o w o r e r r a t ic fu e l p u m p p ressu re . C h e c k fu e l d e liv e ry a n d p ressu re . C o n ta m in a te d fu e l. C h e c k f o r c o n ta m in a n ts in fu e l. C lean s y s te m i f necessary. F u e l f i l t e r p lu g g e d . C h e c k a n d re p la c e as nece ssa ry. F lo a t level t o o lo w . Check and reset float level to specification. M a lf u n c t io n in g f lo a t a n d /o r C h e c k o p e r a tio n o f s y s te m . R e p a ir o r n e e d le a n d seat. re p la c e as necessary. P o w e r p is to n s tu c k o r b in d in g . C h e c k f o r fre e m o v e m e n t o f p o w e r p is to n ( s ) . C le a n a n d c o r r e c t as necessary. F u e l je ts o r passages p lu g g e d C le a n a n d b lo w o u t w it h c o m p re s s e d o r re s tric te d . a ir. Ig n it io n s y s te m m a lf u n c t io n . C h e c k ig n itio n s y s te m . See S e c tio n 6 D . E x h a u s t s y s te m . C h e c k f o r r e s tr ic tio n s . C o r r e c t as necessary. P o o r Gas M ile a g e C u s to m e r d r iv in g h a b its . R u n m ile a g e te s t w it h c u s to m e r d r iv in g i f p o s s ib le . M a k e sure c a r has 2 0 0 0 - 3 0 0 0 m ile s f o r th e " b r e a k - in " p e r io d . Fig. 6C-7--Diagnosis 7 of 8 L IG H T T R U C K SERVICE M A N U A L ENGINE FUEL 6C-9 CARBURETOR DIAGNOSIS CONT'D. CONDITION CORRECTION POSSIBLE CAUSE P o o r Gas M ile a g e L o o s e , b ro k e n o r im p r o p e r ly C h e c k c o n d itio n o f a ll v a c u u m hose ( C o n tin u e d ) ro u te d v a c u u m hoses. r o u tin g s . C o r r e c t as necessary. E n g in e in need o f s e rvice . C h e c k e n g in e c o m p re s s io n , e x a m in e s p a rk p lu g s ; if fo u le d o r im p r o p e r ly g a p p e d , c le a n a n d re ga p o r re p la c e . C h e c k ig n itio n w ir e c o n d itio n a n d c h e c k a n d re s e t ig ­ n it io n t im in g . R e p la c e a ir c le a n e r e le m e n t i f d ir t y . C h e c k f o r r e s tr ic te d e x h a u s t s y s te m a n d in ta k e m a n ifo ld f o r leakage. C h e c k c a r b u r e to r m o u n tin g b o lt to r q u e . C h e c k v a c u u m a n d m e c h a n ic a l adva n ce . C h e c k fu e l ta n k , fu e l lin e s a nd fu e l F u e l lea ks. p u m p f o r a n y fu e l leakage. P o o r Gas M ile a g e H ig h fu e l'le v e l in c a r b u r e to r . C h e c k fu e l in le t n e e d le a n d seat f o r p r o p e r a n d /o r B la c k S m o k e seal. T e s t, u s in g s u c tio n fr o m a v a c u u m f r o m T a il P ipe s o u rc e . I f n e e d le is le a k in g , re p la c e . C h e c k f o r lo a d e d f lo a t . R ese t f lo a t level to s p e c ific a tio n . I f e xcessive fo r e ig n m a te ria l is p re s e n t in th e c a r b u r e to r b o w l, th e c a r b u r e to r s h o u ld be c le a n e d . P o w e r s y s te m in c a r b u r e to r R e m o v e a ir h o rn a n d c h e c k f o r fre e n o t fu n c tio n in g p r o p e r ly . m o v e m e n t o f p o w e r p is to n (s ). C le a n P o w e r p is to n (s ) s tic k in g o r a n d c o r r e c t as n ece ssa ry. m e te rin g ro d s o u t o f je ts . C h o k e s y s te m . C h e c k c h o k e h e a te d a ir tu b e s f o r r o u tin g a n d /o r p lu g g in g w h ic h w o u ld r e s tr ic t h o t a ir f l o w to c h o k e h o u s in g . C h e c k c h o k e lin k a g e f o r b in d in g . C le a n o r re p a ir as r e q u ire d . C h e c k a d ju s tm e n t o f th e r m o ­ s ta tic c o il. R e a d ju s t t o s p e c ific a tio n as r e q u ir e d . C h e c k e le c tr ic c h o k e w ir in g . P lu g g e d a ir c le a n e r e le m e n t. R e p la c e e le m e n t. E x h a u s t sy s te m . C h e c k f o r r e s tr ic tio n s . C o r r e c t as re q u ire d . L o w tir e p ressure o r in c o r r e c t I n fla te tire s to s p e c ific a tio n s a n d use t ir e size. c o r r e c t size tire s . E v a p o ra tiv e e m is s io n c a n is to r See e v a p o ra tiv e s e c tio n (D a ig n o s is ) T ra n s m is s io n m a lf u n c t io n R e fe r t o tra n s m is s io n d ia g n o s is . o r in w r o n g gear* C a r fe e ls lik e i t is P lu g g e d fu e l filte r s . R e m o v e a n d re p la c e filte r s . F a u lt y fu e l p u m p . P e r fo r m fu e l p u m p te s t. r u n n in g o u t o f gas — s u rg in g o c c u rs in m id -s p e e d range R e m o v e a n d re p la c e fu e l p u m p as re q u ir e d . F o re ig n m a te ria l in fu e l s y s te m o r In s p e c t p ip e s ,a n d hoses f o r k in k s a nd k in k e d fu e l p ip e s o r hoses. b e n d s , b lo w o u t to c h e c k f o r p lu g g in g . R e m o v e a n d re p la c e as re q u ire d . Fig. 6C-8--Diagnosis 8 of 8 L IG H T T R U C K SE RV IC E M A N U A L 6C-10 ENGINE FUEL C O N D IT IO N P O S S IB L E CAUSE C O R R E C T IO N Evidence o f fuel loss o r fuel vapor od or A) From area o f fue l ta n k o r fuel cap - Perform pressure check to determ ine possible causes B) From under hood - Perform pressure check to determ ine possible causes 1. Leaking or plugged fuel or EVAP hoses 1. Repair o r replace hoses as necessary 2. Leaking fuel cap 2. Repair o r replace cap as necessary 3. Leaking fuel fille r neck 3. Repair o r replace as necessary 4. Fuel fille r neck gasket surface nicked, burred, o r dented 4. Repair o r replace as necessary 5. Leaking sending u n it o r gasket 5. Repair o r replace as necessary 6. Leaking ta n k sw itch u n it (Dual ta n k system) 6. Replace u n it 7. Inoperative ta n k switch u n it (Dual ta n k system) 7. Replace u n it 8. Plugged or inoperative ta n k pressure co n tro l valve 8. Repair or replace as necessary 1. L iq u id fuel leaking fro m fuel lines, fuel pum p or carburetor 1. T ighten fuel lines, repair or replace fue l pum p or carburetor as necessary 2. Cracked or damaged canisters 2. Repair o r replace canisters as necessary 3. Inoperative bowl vent valve (see Bowl V en t Check Pro­ cedures) 3. Repair or replace hoses Replace canister 4. Inoperative purge valve (see Purge Valve Check Pro­ cedures) 4. Repair o r replace hoses Replace canister 5. Disconnected, m isrouted, 5. Check fo r proper connections, and check ro u tin g as w ell as kinked, deteriorated or damaged vapor hoses or c o n tro l hoses Poor idle o r d riv e a b ility or d riv e a b ility slugging Collapsed fuel ta n k (Loss o f ta n k capacity) c o n d itio n . C orrect as necessary 6. Bowl vent hose m isrouted 6. Reroute hose w ith o u t lo w spots 7. A ir cleaner or air cleaner gasket im p ro p e rly seated 7. Reinstall air cleaner an d/or replace gasket 8. Leaking or inoperative ta n k pressure co n tro l valve 8. Repair or replace as necessary 1. Inoperative purge valve (see Purge Valve Check Procedures) 1. Replace o r repair hoses Replace canister 2. Inoperative bow l vent valve (see Bowl V e n t Check Pro­ cedures) 2. Repair o r replace hoses Replace canister 3. Vacuum leak at ta n k pressure co n tro l valve 3. Repair o r replace hoses a n d/or valve 1. Plugged or pinched vapor pipe o r hoses and defective cap 1. Check all lines fro m ta n k to canister and replace cap 2. Canister filte r plugged and defective cap 2. Replace filt e r in canister and cap 3. Plugged or ru p tu re d diaphragm in ta n k pressure c o n tro l valve and defective cap 3. Replace ta n k pressure co n tro l valve and cap Fig. 6C-9--Evaporative Control System Diagnosis ENGINE FUEL 6C-11 DIAGNOSIS FUEL TANK CORRECTION POSSIBLE CAUSE CONDITION 1. Tank o v e rfille d . Do n o t ''p a c k '' tan k. F ill to a u to m a tic s h u t-o ff. 2. Fuel feed line leaking. 3. Leak in fuel tan k. C orrect as required. Purge tan k and repair or replace ta n k as required. Gasoline O dor 4. Disconnected fuel vapor pipe o r hoses. C onnect pipe or hoses as required. 6. F a u lty f ill cap or tan k neck. Install new cap o r tank neck as required. 1. Plugged o r pinched vapor pipe or hoses, Check all lines fro m tank to canister and & defective cap. replace cap. 2. Canister filte r plugged & de fective cap. Replace filte r in canister & cap. 1. M o u n tin g straps loose. T igh te n straps to specifications. 2. B affle loose. Replace fuel ta n k. 3. Foreign m aterial in tan k. Remove tan k and clean. 1. Tank gage u n it filte r plugged. Replace filte r. 2. Fuel line pinched, plugged or m is-routed. Check open or re-route as required. Collapsed Fuel Tank Fuel Tank Rattles Fuel S tarvation Fig. 6C-10--Fuel Tank Diagnosis LIG H T T R U C K SERVICE M A N U A L w - V CARBURETOR MODEL 1ME 6C1-1 SECTION 6C1 CARBURETOR MODEL 1ME CONTENTS General Description......................................................... On-Vehicle Service................... ...................................... Adjustments..................................................................... Choke Checking Procedure......................................... Idle Mixture Adjustm ent............................................. Carburetor Mounting Torque..................................... Carburetor Replacement.............................................. Solenoid Replacement.................................................. 6C1-1 6C1-7 6C1-7 6C1-7 6C1-7 6C1-7 6C1-7 6C1-8 Choke Coil Replacement.............................................. 6C1-8 Throttle Lever Actuator............................................... 6C1-9 Unit Repair........................................................................ 6C1-10 D isassem bly..................................................................... 6C1-10 Cleaning............................................................................ 6C1-13 Assembly........................................................................... 6C1-13 Adjustment Specifications.............................................. 6C1-16 GENERAL DESCRIPTION The Monojet, carburetor (Fig. 6C1-1) is a single bore downdraft carburetor using a triple venture in conjunction with a plain tube nozzle. Fuel flow through the main metering system is control­ led by a main well air bleed and a variable orifice jet. A power enrichment system is used to provide good perform­ ance during moderate to heavy acceleration and at higher engine speeds. The model 1ME incorporates an integral automatic choke system which uses and electrically heated choke coil. The vacuum diaphragm unit is mounted externally on the air horn and connects to the thermostatic coil lever through a connecting line. The electric choke coil is contained in a choke housing mounted on a bracket attached to the float bowl. Special rivets are installed to retain the factory setting of the choke coil and provide a non-adjustable design. An integral, pleated-paper fuel inlet filter is mounted in the fuel bowl behind the fuel inlet nut to give maximum filtraton of incoming fuel. A check valve on light duty T H R O T T L E LEVER A C T U A T O R (V A C U U M O PER A TED ) VACUUM BR EAK emissions is used in the filter inlet to prevent fuel draining from the fuel system after roll-over. To improve hot engine starting and meet evaporative emission requirements, fuel vapors from the carburetor bowl are vented to the vapor canister on some models. A tube (location F) is added to the air horn to connect air horn and canister. Other features of the Monojet carburetor include an aluminum throttle body for decreased weight and improved heat distribution and a thick throttle body to bowl insulator gasket to keep excessive engine heat from the float bowl. On California models seals have been added in the float bowl to seal the power piston drive rod and the pump lever to prevent escape of fuel vapors to atmosphere. During unit repair, the seals and retainer, where used, must be removed prior to immersion of the float bowl in carburetor cleaner. The carburetor model identification is stamped on a vertical portion of the float bowl, adjacent to the fuel inlet nut (Fig. 6C1-2). If replacing the float bowl, follow the manufacturer’s instructions contained in the service package so that the identification number can be transferred to the new float bowl. An electrically operated idle stop solenoid is used on all models. E L E C T R IC A L CONNECTO R (TO E LE C T R IC CHOKE) Fig. 6C1-1--Model 1ME Carburetor LIG H T T R U C K SERVICE M AN U AL 6C 1-2 CARBURETOR MODEL 1ME INTERNAL VENT TO P A IR BLEED PRESSURE RELIEF VALVE IDLE C H A N N E L R E S T R IC T IO N FLOAT CHECK VALVE SEAT T H R O TTLE VALVE IDLE D IS C H A R G E HOLE Fig. 6Cl-3--Float System Dual throttle return springs are used on all carburetors. The throttle lever has a spun-in plastic bushing, this is used as the bearing surface for the dual throttle return springs. The spun-in plastic return spring bushing will with­ stand normal cleaning time in an approved cold immersion type carburetor cleaner. The bushing is not serviced sepa: rately and should not be removed from the carburetor throttle lever. Six basic systems of operation are used: float, idle, main metering, power enrichm ent, pump and choke. 6C1-3 through 8). Fig. 6C1 -4—Idle System •FACTORY ADJUSTED M A IN WELL A IR BLEED TUBE METERING ROD HANGER POWER PISTON METERING ROD M A IN DISCHARGE NOZZLE DRIVE ROD POWER PISTON SPRING BOOST VENTURI M A IN VENTURI M A IN METERING JET -P L U G PARTTHROTTLE ADJUSTM ENT SCREW * LOWER IDLE A IR BLEED THROTTLE VALVE POWER PISTON A C TU ATING LINKAGE POWER PISTON VA C U U M Fig. 6CT5--Main Metering System Typical L IG H T T R U C K SERVICE M A N U A L CARBURETOR MODEL 1ME 6C 1-3 •F A C T O R Y ADJUSTED "T" DISCHARGE , SPRING RETAINER ,PUMP PLUNGER ft DURATION SPRING PO W ER PIS TO N S P R IN G PUMP RETURN SPRING -AS PLUNGER 'MOVES UP. FUEL FLOWS PAST CUP INTO PUMP WELL M A IN M E TE R IN G JET PLUG PARTTHROTTLE AD JU STM EN T SC REW 1 PUMP ACTUATING LINK PO W ER PIS TO N A C T U A T IN G LIN K A G E TH R O TTLE V A L V E PUMP CUP OPERATION PO W ER P IS TO N V A C U U M Fig. 6Cl-7--Pump System Fig. 6Cl-6--Power Enrichment System CHOKE ROD CHOKE VALVE CHOKE HOUSING CHOKE VACUUM DIAPHRAGM UNIT I PLUNGER e l e c t r ic BUCKING CHOKE \ SPRING CHOKE COIL LINK FAST IDLE CAM FOLLOWER VA CU UM INLET RESTRICTIOr VA CU UM BREAK LINK INSIDE COIL LEVER MANIFOLD J ) VACUUM r HOSE .jJ CHOKE SYSTEM Fig. 6CT8--Choke System LIG H T T R U C K SERVICE M AN U AL 6C1-4 CARBURETOR MODEL 1ME F L O A T LEVEL A D J U S T M E N T G A U G E FROM TO P O F C A S T IN G TO TO P O F IN D E X P O IN T A T TO E O F FLOAT ( T ) B E N D H E R E TO A D JU S T F L O A T UP O R DOW N 1 )H O L D F L O A T R E T A IN IN G ' ^ P I N F IR M L Y IN P L A C E PUSH D O W N ON EN D O F F L O A T A R M , A G A IN S T TO P O F F L O A T N E E D L E M E T E R IN G R O D A D J U S T M E N T ( 3 )H O L D POWER PISTO N D O W N A N D SW ING M E T E R IN G R O D H O L D E R OVER F LA T SURFACE ( 5 ) BEN D HERE T O A D JU S T (G A S K E T R E M O V E D ) O F BO W L C A S T IN G N E X T T O C A R B U R E T O R BORE (7), 1 ) R E M O V E M E T E R IN G RO D B Y H O L D IN G T H R O T T L E V A L V E W ID E O PEN . PUSH ^ 4 J S P E C IF IE D P LU G D O W N W A R D ON M E T E R IN G G A U G E - S L ID E F IT R O D A G A IN S T SPR IN G T E N S IO N , T H E N S L ID E B A C K O U T ID L E M E T E R IN G ROD O U T OF STOP S O L E N O ID — S L O T IN H O L D E R A N D HO LD TH R O TT LE R E M O V E FR O M M A IN V A LV E C OM PLETELY C LO S E D M E T E R IN G JE T. F A S T ID LE A D J U S T M E N T SUPPORT LEVER WITH PLIERS-BENDTANGIN OR OUT TO OBTAIN SPECIFIED FAST IDLE R.P.M. (SEE INSET). NOTE: M A N U A L C H O K E M ODELS W ITH SM O O TH CONTOUR C A M SURFACE ROTATE FAST IDLE C A M CLOCKWISE TO ITS FARTHEST UP PO SITIO N. PREPARE VEHICLE FOR A D JU S TM E N TS SEE EM ISSIO N LABEL ON VEHICLE. IG N ITIO N T IM IN G SET PER LABEL. SECOND jC HIGH FAST IDLE CAM STEPS ADJUST CURB IDLE SPEED WITH IDLE STOP SOLENOID. Fig. 6C1-9--1ME Adjustments - 1 of 3 L IG H T T R U C K SERVICE M A N U A L CARBURETOR MODEL 1ME 6C1-5 C H O K E C O IL LEVER A D J U S T M E N T - 1M E © HOLD CHOKE VALVE 120' PLUG GAUGE M U S T PASSTHRO UG H HOLE IN LEVER A N D ENTER HOLE IN C ASTIN G COMPLETELY CLOSED o PLACE FAST IDLE CAM FOLLOWER ON H IG H EST STEP OF FAST IDLE CAM C H O K E R O D (F A S T ID LE C A M ) A D J U S T M E N T (2N D STEP) GAUGE BETWEEN LOWER EDGE OF CHOKE VALVE (AT CENTER) A N D IN SID E AIR HORN WALL. © HOLD DOW N ON CHOKE V A L V E ROD IN END OFSLO W ITH FAST IDLE A DJUSTM ENT M ADE. FAST IDLE CAM FOLLOWER M U S T BE HELD FIRM LY ON SECOND STEP OF FAST IDLE C A M A G A IN S T H IG H EST STEP Fig. 6C1-10--1ME Adjustments - 2 of 3 LIG H T TR U C K SERVICE M AN U AL 6C1-6 CARBURETOR MODEL 1ME V A C U U M BREAK A D J U S T M E N T - 1M E (B O W L S ID E ) v 0 NOTE: HOLD GAUGE PUSH DOW N ON CHOKE VALVE (COMPRESS PLUNGER BUCKING SPRING A N D SEAT PLUNGER STEM ON M ODELS SO EQUIPPED). PLACE GAUGE BETWEEN LOWER EDGE OF CHOKE VALVE AND IN SID E AIR HORN WALL © USE OUTSIDE V A C U U M SOURCE TO SEAT D IA P H R A G M . PLACE FAST IDLE CAM FOLLOWER ON HIGHEST STEP OF C A M . NOTE: ON DELAY FEATURE M O D ELS, COVER PLUG AND PURGE BLEED HOLE W ITH 1" SQ U A R E PIECE OF M A S K IN G TA PE. REMOVE AFTER ADJUSTMENT. U N L O A D E R A D J U S T M E N T - 1M E (WIDE OPEN KICK) © INSTALL CHOKE COIL IN CHOKE H O USING A N D INDEX PROPERLY (SEE NOTE) NOTE: IF CHOKE COIL IS W A R M , COOL DOW N TO PO IN T WHERE CHOKE VALVE WILL CLOSE FULLY. GAUGE BETWEEN LOWER EDGE OF CHOKE VALVE A N D IN SID E A IR HORN W ALL (SEE NOTE). © HOLD THROTTLE VALVE W IDE OPEN BEND TA N G TO A D JU S T (SEE INSET). ID LE SP EE D A D J U S T M E N T TO ADJUST BASE IDLE TURN 1/8” HEX SCREW (SOLENOID NOT ENERGIZED) © NOTE: ENGINE M U ST BE W A R M -C H O K E WIDE OPEN FAST IDLE CAM FOLLOWER OFF STEPS OF C A M (SEE EM ISSIO N LABEL) SET CURB IDLE TO SPECIFICATIONS —TURN ASSEM BLY IN OR OUT TO A D JU S T R P M. (SOLENOID ENERGIZED) Fig. 6C1-11--1ME Adjustments - 3 of 3 LIG H T T R U C K SERVIC E M A N U A L CARBURETOR MODEL 1ME 6C 1-7 ON-VEHICLE SERVICE 1ME CARBURETOR ADJUSTMENTS Refer to figure 6C1-9 through 6C1-11 for adjustment specifications and procedures. Choke Checking Procedure 1. Remove air cleaner. With engine off, hold throttle half open. Open and close choke several times. Watch linkage to be certain all links are connected and there are no signs of damage. 2. If choke or linkage binds, sticks, or works sluggishly, clean with Choke Cleaner X -20-A or equivalent. Use cleaner as directed on can. Refer to disassembly instructions for additional direction if cleaning does not correct. 3. Visually inspect carburetor to be certain all vacuum hoses are connected. Inspects hoses for cracks, abra­ sions, hardness or other signs of deterioration. Replace or correct as necessary. 4. Make sure vacuum break diaphragm shaft is fully extended when engine is off. If shaft is not fully extended, replace vacuum break assembly. Start engine - vacuum break diaphragm shaft should fully retract within 10 seconds. If unit fails to retract, replace vacuum break assembly. 5. Allow choke to cool so that when throttle is opened slightly choke blade fully closes. This check must be performed at an ambient temperature of 60°F to 80°F. 6. Start engine and determine time for choke blade to reach full open position. (Start timer when engine starts). 7. If the choke blade fails to open fully within 3-1/2 minutes proceed with steps 8-9-10 below. 8. Check voltage at the choke heater connection. (Engine must be running). If the voltage is approximately 12-15 volts, replace the electric choke unit. 9. If the voltage is low or zero, check all wires and connections. If the connections at the oil pressure switch are faulty, the oil warning light will be off with the key "on" and engine off. If the fuse is blown, the radio or turn signal indicator will be inoperative. Repair wires or replace fuses as required. 10. If step 9 is good, replace oil pressure switch. N o gasket is used between the choke cover and the choke housing due to grounding requirements. Checking Solenoid 1. Turn on ignition, but do not start engine. 2. Open throttle to allow solenoid plunger to extend. 3. Hold throttle lever wide open, feel end of plunger and disconnect wire at solenoid. 4. Plunger should move. Some spring tension should be felt. 5. If plunger did not move, back out 1/8 hex screw (counterclockwise) one full turn and repeat steps 3 and 4. 6. If plunger moves in step 5, connect wire to solenoid and adjust idle speed. 7. If plunger did not move in step 5 insert test lamp (1893 bulb or smaller) between solenoid feed wire and ground. 8. If lamp lights, replace solenoid. 9. If lamp does not light, locate cause of open circuit in solenoid feed wire. IDLE MIXTURE ADJUSTMENT (LEAN DROP) For Heavy Duty Emission Vehicles Without 4 Barrel 1. Set parking brake and block drive wheels. 2. Remove air cleaner for access to carburetor, but keep vacuum hoses connected. 3. Disconnect and plug other hoses, as directed on Emis­ sion Control information Label under the hood. 4. Start engine and bring to normal operating tempera­ ture, choke open, air conditioning off. 5. Connect an A C CURA TE tachometer to engine. 6. Disconnect vacuum advance and plug hose. Check ignition timing. If necessary, adjust to specification shown on Emission Control Information Label. Recon­ nect vacuum advance. 7. Carefully remove cap from idle mixture screw. Be careful not to bend screw. Lightly seat screw, then back out just enough so engine will run. 8. Place transmission in Neutral. 9. Back screw out (richen) 1/8 turn at a tim e until maximum idle speed is obtained. Then set idle speed to value shown on Engine Emission Control Information Label. Repeat step 9 to be certain you have maximum idle speed. 10. Turn screw in (lean) with 1/8 turn increments until idle speed reaches value shown on Engine Emission Control Information Label. 11. Reset idle speed to specification shown on Engine Emission Control Information Label. 12. Check and adjust fast idle as described on the Engine Emission Control Information Label. 13. Reconnect vacuum hoses. Install air cleaner. 14. Recheck idle speed. If necessary, reset to specification. CARBURETOR MOUNTING TORQUE When torquing carburetor after removed, overhaul, replacement or when installing a new heat insulator, torque mounting bolts, in a clockwise direction to 23 N-m (198 in. lbs.). When retorquing carburetor at recommended mainte­ nance intervals, retorque to 16 N-m (144 in. lbs.) maximum. CARBURETOR REPLACEMENT (FIG. 6C1-12) Removal Flooding, stumble on acceleration and other perform­ ance complaints are, in many instances, caused by presence of dirt, water, or other foreign matter in carburetor. To aid in diagnosing cause, carburetor should be carefully removed from engine without draining fuel from bowl. Contents of fuel bowl may then be examined for contamination as carburetor is disassembled. Check filter. LIG H T T R U C K SERVICE M A N U A L 6C1-8 CARBURETOR MODEL 1ME 2. Disconnect electrical connector at solenoid. 3. Unscrew and assembly. remove solenoid from float bowl Installation 1. Hold choke valve wide open so that fast idle cam follower clears fast idle cam. 2. Install solenoid and turn in until it contacts lever tang. 3. Connect electrical connector. 4. Install air cleaner. 5. Check and adjust idle speed. CHOKE COIL REPLACEMENT (Fig. 6Cl-12a) Choke mechanism should be checked for free opera­ tion. A binding condition may have developed from petro­ leum gum formation on the choke shaft or from damage. Choke shafts can usually be cleaned without disassembly by using Carbon X (X 55) or equivalent. 1. 2. 3. 4. 5. 6. Remove air cleaner. Disconnect fuel and vacuum lines from carburetor. Disconnect electrical connector at choke. Disconnect accelerator linkage. Disconnect solenoid electrical connector. Remove carburetor attaching nuts and remove car­ buretor and solenoid assembly attachment. 7. Remove insulator gasket. Installation It is good shop practice to fill carburetor bowl before installing carburetor. This reduces strain on starting motor and battery and reduces the possibility of backfiring while attempting to start engine. A small supply of fuel will enable carburetor to be filled and the operation of float and intake needle and seat to be checked. Operate throttle lever several times and check discharge from pump jets before installing carburetor. .V gff Fig. 6C l-12 a--C hoke Coil 1. Be certain throttle body and intake manifold sealing surface are clean. 2. Install carburetor insulator. 3. Install carburetor over manifold studs. 4. Install vacuum and fuel lines at carburetor 5. Install attaching nuts and tighten alternately to 21 N-m (16 ft. lbs.). 6. Tighten fuel line. 7. Connect accelerator linkage. 8. Connect choke and solenoid electrical connectors. 9. Install air cleaner. 10. Check and adjust idle speed. SOLENOID REPLACEMENT An inoperative solenoid should be replaced. Removal 1. Remove carburetor air cleaner. LIG H T T R U C K SERVICE M A N U A L Fig. 6 C 1-12b—Installing Choke CARBURETOR MODEL 1ME 6 C 1-9 3 / 16 ’ ADAPTER (Procure steel tubing locally) Fig. 6Cl-12c--Riveting Adapter 1. Remove air cleaner and disconnect choke electrical connector. 2. Align a # 2 1 drill (.159") on rivet head and drill only enough to remove rivet head. After removing rivet heads and retainers, use a draft and small hammer to drive the remainder of the rivets out of the Use care in drilling to prevent damage to choke cover or housing. Remove the three retainers and choke cover assembly from choke housing. 3. Remove choke coil from housing. 4. Install the choke cover and coil assembly in choke housing as follows: a. Install the choke cover and coil assembly in the choke housing, aligning notch in cover with raised casting projection on housing cover flange. Make sure coil pick-up tang engages the inside choke coil lever. A choke cover retainer kit is required to attach choke cover to choke housing. Install proper retainers and rivets contained in kit using suitable blind rivet installing tool (Fig. 6 C 1-12b). It may be necessary to use an adapter (tube) if installing tool interferes with electrical connector tower on choke cover (Fig. 6C112c). 5. Connect choke electrical connector. 6. Start engine, check operation of choke and then install air cleaner. THROTTLE LEVER ACTUATOR ADJUSTMENT (Fig. 6C1-12d) Adjust the Throttle Return Control (TRC) idle speed to specification, shown on Vehicle Emission Label, as follows: 1. Disconnect hose from solenoid valve to actuator at the solenoid valve, and connect hose to an external vacuum source equipped with a vacuum gage. 2. Check the throttle lever, shaft, and linkage to be sure that they operate freely without binding or sticking. 3. Apply 20 in. Hg. vacuum to the actuator. Manually open the throttle slightly and allow to close against the extended actuator plunger. Note the engine rpm. 4. If the rpm is not within the specified TRC speed range, then turn the screw on the actuator plunger in the appropriate direction and repeat step 3 until the specified TRC speed range is obtained. LIG H T T R U C K SERVICE M A N U A L 6C1-10 CARBURETOR MODEL 1ME Fig. 6 C M 2 d -T R C UNIT REPAIR DISASSEMBLY Place carburetor on a holding fixture to prevent damage to throttle valve. Air Horn Removal 1. Remove choke vacuum break diaphragm hose. 2. Remove vacuum break diaphragm assembly from air horn by removing two attaching screws. These screws have a tapered head and do not use lockwashers. Remove diaphragm plunger stem from diaphragm to choke lever link. (Fig. 6 C 1-13). NOTICE: Screw that retains vacuum break lever to choke shaft is installed with thread torque retaining compound. It is not necessary to remove this screw and lever unless choke shaft replacement is required. 3. Remove fast idle cam attaching screw; then remove fast idle cam (Fig. 6C1-14). Fig. 6C1-13--Vacuum Break Diaphragm LIG H T T R U C K SERVIC E M A N U A L Remove choke rod from choke coil lever on end of choke shaft. 4. R em ove choke coil assem bly as follows; Align a#21 drill (.159 ") on rivet head and drill only enough to rem ove rivet head. Drill the tw o remaining rivet heads and then use a drift and small hammer to drive the remainder o f the rivets out o f the choke housing. R em ove the three retainers and choke cover assem ­ bly from choke housing. 5. Choke coil housing need not be removed from float bowl unless replacement is necessary. To remove choke housing, remove three attaching screws from float bowl. Two screws have lockwashers and the one facing the choke housing has a tapered head for locating choke housing. 6. Remove four remaining air horn to bowl attaching screws and lockwashers (three long and one short screw). 7. Remove air horn by lifting and twisting back towards choke housing so that the choke coil lever link will disengage from the choke coil lever at the choke Fig. 6C1-14--Fast Idle Cam CARBURETOR MODEL 1ME 6C 1-11 housing, invert and place on clean bench. Air horn to float bowl gasket can remain on bowl for removal later (Fig. 6 C 1-15). Disassembly 1. If required, the choke valve and choke shaft can be removed from air horn by removing the screw that retains the vacuum break lever to the choke shaft. Care should be exercised when removing this screw because it is retained in place by thread torque retaining compound. Remove the two attaching screws from the choke valve, then, remove the choke valve and choke shaft from air horn. The choke valve screws are staked in place so it will be necessary to file off staking and re-stake during assem­ bly. Do not bend choke shaft when restaking. 2. N o further disassembly of the air horn is necessary. Float Bowl Disassembly 1. Remove air horn to float bowl gasket. Gasket is slit next to metering rod lever so that it can be slid over lever for ease in removal. (Fig. 6C1-16). 2. Remove float assembly from float bowl by lifting upward on float hinge pin. Remove hinge pin from float arm. 3. Remove float needle from seat. 4. Disconnect accelerator pump and power piston actua­ tor lever from end of throttle shaft by removing lever attaching screw (Fig. 6C1-17). 5. Hold down on power piston while removing lever. Power piston spring and metering rod assembly may now be removed from float bowl (Fig. 6 C 1-18). 6. Remove lower end of power piston link from actuator lever by rotating until tang on rod slides out of notch in lever. Fig. 6CT16--Float Bowl Disassembly 7. Remove actuator lever from lower end of accelerator pump link in same manner. 8. Push down on accelerator pump and remove actuator link by rotating until tang on rod aligned with slot on pump plunger lever. Remove the link. 9. Remove pump assembly from float bowl (Fig. 6 C 1-19). 10. Remove pump return spring and power piston spring from float bowl (Fig. 6 C 1-19). 11. Remove "T" guide and pump discharge spring using needle nose pliers (Fig. 6C1-20). 12. Pump discharge ball and idle tube can be removed at the same time by inverting the bowl. 13. Remove main metering jets from bottom of fuel bowl. Fig. 6C1-15--Air Horn Removal Fig. 6CT17--Pump and Power Piston Actuator Lever LIG H T T R U C K SERVICE M A N U A L 6C 1-12 CARBURETOR MODEL 1ME Fig. 6Cl-18--Float Bowl Assembly 14. Remove float needle seat and gasket using Tool J-22769. 15. The idle stop solenoid can be removed at this time if desired. 16. Remove the fuel inlet nut, filter and spring (Fig. 6C12 1 ). N o further disassembly of the float bowl is required. Fig. 6Cl-20--Pump Discharge " T " Retainer Throttle Body (Fig. 6C1-22) 1. Invert carburetor bowl on bench and remove two throttle body to bowl attaching screws. Throttle body and insulator gasket may now be removed. 2. N o further disassembly of the throttle body is neces­ sary unless the idle mixture needle is damaged or the idle channels need cleaning. If necessary to remove the idle mixture needle, cut the tang from the plastic limiter cap. Do not install a replacement cap as a bare mixture screw is sufficient to indicate that the mixture has been readjusted. SPRING CHECK VALVE FUEL FILTER GASKET INLET NUT Fig. 6C1-19--Metering Rod and Accelerator Pump LIG H T T R U C K SERVIC E M A N U A L Fig. 6C1-21-Fuel Filter and Check Valve CARBURETOR MODEL 1ME 6C 1-13 4. Install two throttle body to bowl attaching screws and lockwashers. Tighten even and securely to 20 N-m (15 ft. lbs.). Float Bowl 1. Install fuel filter spring, filter, and check valve assem­ bly, (if used), inlet nut and gasket rubber seal on check valve faces fuel inlet nut. The fuel inlet check valve must be installed (where required) in the filter to meet Motor Vehicle Safety Standards (M .V .S.S.) for roll-over. New service re­ placement filter include the check valve, where required. Fig. 6Cl-22--Throttle Body Due to the close tolerance fit of the throttle valve in the bore of the throttle body, do not remove the throttle valve or shaft. CLEANING AND INSPECTION The carburetor should be cleaned in a cold immersion type cleaner. Rubber and plastic parts should not be immersed in carburetor cleaner. However, the air horn which has the plastic relief valve will withstand normal cleaning in carburetor cleaner. 1. Thoroughly clean carburetor castings and metal parts in an approved carburetor cleaner such as Carbon X (X -55) or equivalent. 2. Blow out all passages in castings with compressed air. Do not pass drills through jets or passages. 3. Examine float needle and seat assem bly for wear. Install a new factory matched set if worn. 4. Inspect upper and iower casting sealing surfaces for damage. 5. Inspect holes in levers for excessive wear or out of round condition. If levers are worn they should be replaced. 6. Examine fast idle cam for excessive wear or damage. 7. Check throttle and choke levers and valve for binds and other damage. 8. Check all springs for distortion or loss in tension; replace as necessary. CARBURETOR ASSEMBLY 2. Install idle stop solenoid and spring, if removed. Adjust later for correct idle speed. 3. Install main metering jet into bottom of fuel bowl. Tighten securely. 4. Using wide blade screwdriver install needle seat and gasket. 5. Install idle tube flush with bowl casting. 6. Install pump ball, spring and "T" into pump discharge hole (Fig. 6C1-20). 7. Drive pump discharge "T" in until flush with bowl casting. 8. Install accelerator pump return spring. 9. Install power piston return spring into piston cavity in the bowl. 10. Install lower end of pump link into actuator lever which fits on throttle shaft. Ends of link point toward car­ buretor. Bend in link faces fuel inlet nut. 11. Install curved power piston actuator link into throttle actuator lever. End protrudes outward away from throttle bore and has tang which retains link to lever. 12. Install pump plunger assembly into pump well with actuating lever protruding through bottom of bowl casting. Push downward on pump lever and install pump assembly drive link into slot in lower end of shaft. Tang on upper end of link retains link to pump shaft (Fig. 6C1-23). ALTITUDE MODELS ONLY , PUMP LEVER , EVAPORATIVE SEAL* " T ‘ DISCHARGE -SPRING RETAINER PUMP PLUNGER & DURATION SPRING After carburetor has been disassembled, new gaskets and filter must be used. Throttle Body (Fig. 6C1-22) 1. If removed, install idle mixture needle and spring into throttle body until lightly seated. Back out two turns as a preliminary adjustment. Final idle mixture adjust­ ment will be made on vehicle. 2. Invert float bowl and install new throttle body to bowl insulator gasket. 3. Install throttle body on bowl gasket so all holes in throttle body are aligned with holes in gasket. PUMP RETURN SPRING -AS PLUNGER MOVES UP. FUEL FLOWS PAST CUP INTO PUMP WELL PUMP CUP OPERATION Fig. 6Cl-23--Pump Drive Link LIG H T T R U C K SERVICE M A N U A L 6C1-14 CARBURETOR MODEL 1ME 13."Assembly metering rod to holder on power piston. Spring must be on top of arm when assembled cor­ rectly. Then install power piston actuating rod (right angle end) into slot in the power piston. 14. Install power piston, metering rod and drive rod assembly into the float bowl. End of drive rod must enter hole in bowl and end of metering rod into jet. © B E N D IN G T O O L © H O L D POW ER P IS TO N D O W N /P L U G GAUGE 15. Before fastening power piston and pump actuator lever to end of throttle shaft, hold power piston assembly down and slide upper end of curved power piston actuator link into lower end of power piston actuating rod. © F L O A T BOW L SURFACE (G A S K E T R E M O V E D ) 16. Install actuating lever on end of throttle shaft by aligning flats or lever with flats on shaft. Install lever retaining screw and tighten securely. © B A C K O U T ID L E SPEED SCREW H OLD TH R O TTLE V A LV E C O M P L E T E L Y C LO S E D 17. Install float needle valve on to float arm hooking pull clip over edge of float arm. 18. Install float hinge pin into float arm. Install float needle into seat and float with hinge pin into float bowl. Hinge pin should in locating channels in float bowl. Float Level Adjustment (Fig. 6C1-24) 1. Hold float retaining pin firmly in place push down on float arm at outer end against top of float needle, as shown. 2. Use adjustable "T" scale and measure distance from top of float at index point on toe to float bowl gasket surface (gasket removed). 3. To adjust, bend float pontoon up or down at float arm junction. Fig. 6Cl-25--Metering Rod Adjustment 4. Holding downward pressure on power piston, swing metering rod holder over flat surface of bowl casting next to carburetor bore. 5. Insert gage between bowl casting and lower surface of metering rod holder. Gage should have a slide fit between both surfaces, as shown. 6. To adjust, carefully bend metering rod holder up or down. 7. Install air horn gasket on float bowl by carefully sliding slit portion of gasket over metering rod holder. Then align gasket with dowels provided on top of bowl casting and press gasket firmly in place. Metering Rod Adjustment (Fig. 6C1-25) Air Horn 1. Open throttle valve, slide metering rod out of holder and remove from main metering jet. 2. To check adjustment, back out 1/8" hex screw on idle stop solenoid and rotate fast idle cam so that cam follower is not contacting steps on cam. 3. With throttle valve completely closed, apply pressure to top of power piston and hold piston down against stop. Fig. 6Cl-24--Float Level Adjustment LIG H T T R U C K SERVIC E M A N U A L Fig. 6Cl-26--lnstalling Air Horn CARBURETOR MODEL 1ME 6C 1-15 3. Install the choke vacuum break diaphragm assembly using two short air horn screws opposite the choke housing, connecting the choke vacuum break dia­ phragm link to slotted diaphragm plunger stem. The two attaching screws for the choke vacuum break assembly have tapered heads for locating choke dia­ phragm bracket. Make sure to use these in this location. Tighten all air horn screws evenly and securely using proper tightening sequence (Fig. 6C127). 4. If removed, install choke housing to float bowl using three attaching screws. Two screws have lockwashers and the other one which face the choke housing has a tapered head for locating choke housing. 5. Install fast idle cam, and fast idle cam link to upper choke lever assembly. Numbers on fast idle cam face outward. 6. Install the choke cover and coil assembly in choke housing as follows: 1. Install choke shaft assembly and choke valve into air horn, if removed. Align choke valve, tighten two retaining screws and stake securely in place. NOTICE: Apply a torque retaining compound to the vacuum break lever retaining screw and install lever to choke shaft. 2. Install air horn to float bowl by engaging choke coil lever link into notched hole in choke coil lever on choke housing. Then carefully twist and lower air horn onto float bowl. Install three long and one short air horn to float bowl attaching screws and lockwashers (Fig. 6C126). a. Install the choke cover and coil assembly in the choke housing, aligning notch in cover with raised casting projection on housing cover flange. Make sure coil pick-up tang engages the inside choke coil lever. A choke cover retainer kit is required to attach choke cover to choke housing. Install proper retainers and rivets contained in kit using suitable blind rivet installing tool. It may be necessary to use an adapter (tube) if installing tool interferes with electrical connector tower on choke cover. Do not use a gasket between electric coil and housing, as the coil is electrically grounded through housing. 7. Install choke vacuum diaphragm hose to tube on diaphragm and connect to vacuum tube on bowl. L IG H T T R U C K SERVICE M A N U A L 6C 1-16 CARBURETOR MODEL 1ME ADJUSTMENT SPECIFICATIONS - MODELS - ME - M (MONOJET) CARBURETOR NUMBER FLOAT LEVEL METERING ROD CHOKE ROD CAM ADJ VACUUM BREAK UNLOADER Inches Inches Inches Inches Inches .090 .275 .400 .520 N.A. .090 .275 .400 .520 .090 .275 .400 .520 N.A. N.A. 17081009 ME 17081309 ME 11/32 11/32 17081329 ME 11/32 CHOKE SETTING t- N.A. = NOT ADJUSTABLE Fig. 6Cl-28--Adjustment Specifications LIG H T T R U C K SERVIC E M A N U A L CARBURETOR MODEL 2SE 6C2-1 SECTION 6C2 CARBURETOR MODEL 2SE CONTENTS General Description......................................................... Carburetor Operation.................................................... On-Vehicle Service.......................................................... Adjustments..................................................................... Checking Idle Solenoid................ ................................ Solenoid Replacem ent................................................... Choke Coil Replacement.............................................. Idle Mixture Check and Adjustment........................ 6C2-1 6C2-2 6C2-4 6C2-4 6C2-4 6C2-4 6C2-14 6C2-14 Carburetor Mounting Torque..................................... 6C2-15 Carburetor Replacem ent.............................................. 6C2-15 Unit Repair........................................................................ 6C2-15 Disassem bly..................................................................... 6C2-16 Cleaning............................................................................ 6C2-19 Assembly........................................................................... 6C2-20 Adjustment Specifications.............................................. 6C2-25 GENERAL DESCRIPTION The Model 2SE is a two barrel, two stage carburetor of down-draft design for use on the 4.1 litre engine. To reduce carburetor weight, aluminum die castings are used for the air horn, float bowl, throttle body and choke housing. A heat insulator gasket is used between the throttle body and float bowl to reduce heat transfer to the float bowl. The primary stage has a triple venturi, with a small 35mm bore that results in good fuel control during idle and part throttle operation. The secondary stage has a large 46mm bore that provides sufficient air capacity for engine power require­ ments. An air valve is used in the secondary stage with a single tapered metering rod. On the 2SE models, an integral 2" pleated paper fuel filter with check valve is mounted in the front of the float bowl behind the fuel inlet nut to give maximum filtration of incoming fuel. The check valve is used to shut off fuel flow to the carburetor and prevent fuel leaks if a vehicle roll-over should occur. The float chamber is located adjacent to the primary and secondary bores. This feature assures adequate fuel supply to both carburetor bores during all vehicle normal maneuvers. A single pontoon float, brass needle seat, and a rubber tipped float valve with pull clip are used to control fuel level in the float chamber. The float chamber is internally vented through a vertical vent cavity in the air horn. Above this vent cavity is a removable vent stack assembly that has a small meshed screen as its top portion. This vent stack provides the correct height for the internal vent and the screen offers necessary backfire protection to the float chamber. The Model 2SE float chamber also is externally vented through a tube in the air horn. A hose connects this tube directly to a vacuum operated vapor vent valve. When the engine is not running, the canister vapor vent valve is open allowing fuel vapors from the float chamber to pass into the canister where they are stored until normally purged. The venting of fuel vapors from the carburetor float bowl to the canister meets evaporative emission requirements and improves hot engine starting. An adjustable part throttle screw is used in the float bowl to aid in refinement of fuel mixtures for good emission control. This screw is pre-set at the factory and a plug is installed to prevent tampering and to seal against any fuel L IG H T T R U C K SERVICE M A N U A L 6C2-2 CARBURETOR MODEL 2SE leaks. No attempt should be made to adjust this screw in the field. If it becomes necessary to replace the float bowl, the new service float bowl will include an adjustable part throttle (A.P.T.) screw which has been pre-set at the factory and plugged as required. A hot idle compensator assembly (when used) is located in the air horn casting. The opening and closing of the hot idle compensator valve is controlled by a bi-metal strip that is calibrated to a specific temperature. When the valve opens, additional air is allowed to by-pass the throttle valves and enters the intake manifold to prevent rough idle during periods of hot engine operation. The idle mixture needle is recessed in the throttle body casting and sealed with a hardened steel plug to discourage tampering with the factory adjusted mixture setting in the field which could upset exhaust emissions. The plug must not be removed and idle mixture screw re-adjusted unless required due to major carburetor overhaul or throttle body replacement in which case special service procedures must be carefully followed. The choke system of the 2SE carburetor uses a dual vacuum break system. The front (primary side) vacuum break unit with bracket is mounted on the air horn and the rear unit is mounted on the idle speed solenoid bracket located on the secondary side of the carburetor. An electri­ cally heated thermostatic choke coil is mounted in the choke housing located on the secondary side of the carburetor. To provide a non-adjustable design to discourage field readjust­ ment of factory settings, the 2SE carburetor usues vacuum break rods of a non-bendable design, a special cap over the vacuum break unit adjustment screw, a special notch in choke cover which must be indexed with a raised boss cast in cover mounting flange on the choke housing, and special rivets (with retainers) to retain choke thermostatic cover and coil assembly in choke housing. VENTSTACK HOT IDLE COMPENSATOR SECONDARY AIR VALVE SECONDARY AIR VALVE LEVER CHOKE VALVE PUMP LEVER CHOKE HOUSING /P R IM A R Y SIDE ♦/V A C U U M BREAK SECONDARY SIDE VACUUM BREAK SLOW IDLE SPEED SCREW Sr ■ FAST IDLE ADJUSTING SCREW Fig. 6C2-l--M odel 2SE Carburetor LIG H T T R U C K SERVIC E M A N U A L The 2SE carburetor has a separate screw located in the primary throttle lever for fast idle speed adjustment. A separate screw, located in the throttle body, is used to make the base speed setting (solenoid de-energized). The carburetor model identification is stamped verti­ cally on the float bowl in a flat area adjacent to the vacuum tube Figure 6C2-2). If replacing the float bowl, follow the manufacturer’s instructions contained in the service pack­ age so that the identification number can be transferred to the new float bowl. Refer to the carburetor part number on the bowl when servicing the carburetor. An exhaust gas recirculation system (E.G.R.) is used on all applications to help control oxides of nitrogen. The vacuum supply ports necessary to operate the recirculation valve are located in the throttle body and connect through a channel to a tube (location C) in the float bowl. This tube is connected by a rubber hose to the E.G.R. valve. California models use a fixed idle air by-pass system to reduce the amount of air flowing through the carburetor primary venturi to prevent the main nozzle from feeding fuel at idle. On the 2SE carburetor, the primary and secondary throttle shafts, the secondary actuating lever and lock-out lever are coated with a special coating to reduce friction and wear in these operating parts. Also, the secondary throttle bore and valve are coated with a special graphite compound for minimum air leakage past the valve for good idle air control. Care should be taken during carburetor service to not disturb or damage these coatings. A throttle body mounted idle speed solenoid is used to position the primary throttle valve to obtain idle speed requirements of the engine. Carburetor Operation The m odel 2SE carburetor has six basic system s. T hey are float, idle, main metering, power, pump and choke (Fig. 6C2-3). CARBURETOR MODEL 2SE FLOAT HINGE HOT IDLE COMPENSATOR IDLE CROSS-OVER PASSAGE •EXHAUST GAS RECIRCULATION PLASTIC INSERT 6C2-3 UPPER IDLE AIR BLEED PULL CLIP IDLE CHANNEL RESTRICTION VENT TUBE TO CANISTER FLOAT VALVE TIMED VACUUM PORT FOR E.G.R.* LOWER IDLE AIR BLEED THROTTLE VALVE (DOTTED LINE - OFF IDLE POSITION) OFF IDLE PORT _ IDLE DISCHARGE HOLE — PLUG IDLE MIXTURE SCREW AND SPRING IDLE SYSTEM FLOAT SYSTEM (TYPICAL) SIDE MAIN WELL AIR BLEED TOP MAIN WELL AIR BLEED CALIBRATION SCREW (FACTORY ADJUSTED) METERING ROD HANGER SECONDARY METERING ROD , SECONDARY METERING JET MAIN (PRIMARY) METERING ROD MAIN DISCHARGE NOZZLE SECONDARY AIR VALVE (OPEN) MAIN METERING ROD ■ FUEL PICKUP TUBE ■ MAIN METERING JET POWER PISTON POWER PISTON SPRING PLUG PART THROTTLE CALIBRATION SCREW (FACTORY ADJUSTED) SECONDARY THROTTLE VALVE VACUUM CHANNEL (TO POWER PISTON) (TYPICAL) PUMP SUCTION BREAKER SECONDARY SIDE VACUUM BREAK LINK PUMP DISCHARGE SPRING AND BALL RETAINER PUMP ROD (ACTUATED BY THROTTLE LEVER) VACUUM CHANNEL (TO POWER PISTON) POWER SYSTEM (INCLUDING SECONDARY STAGE) MAIN METERING SYSTEM PUMP DISCHARGE SPRING AND BALL (SHOWN UNSEATED) FUEL WELL (SECONDARY P U M P LE V E R INTERMEDIATE CHOKE IN T E R M E D IA T E CHOKE VALVE CHOKE LEVER „ VACUUM BREAK AND CHOKE LEVER ---- VACUUM BREAK LINK AIR VALVE ROD AP DURATION SPRING PUMP PLUNGER CUP SEAL (SEATED) PUMP CUP OPERATION AS PLUNGER MOVES UP, CUP SEAL UNSEATS FROM PLUNGER HEAD AND FUEL FLOWS PAST CUP INTO . PUMP WELL PRIMARY SIDE VACUUM BREAK UNIT (AIR VALVE DASHPOT) EXPANDER SPRING PUMP RETURN SPRING DISCHARGE PASSAGE FAST IDLE CAM SECONDARY SIDE VACUUM BREAK UNIT SECONDARY LOCKOUT LEVER CHOKE SYSTEM PUMP SYSTEM Fig. 6C2-3--Carburetor Systems LIG H T T R U C K SERVICE M A N U A L 6C2-4 CARBURETOR MODEL 2SE ON-VEHICLE SERVICE MODEL 2SE ADJUSTMENTS Before checking or resetting the carburetor as the cause of poor engine performance or rough idle, check ignition system including distributor, timing, spark plugs and wires. Check air cleaner, evaporative emission system, EFE system, PCV system, EGR valve and engine compression. Also inspect intake manifold vacuum hose gaskets and connections for leaks and check torques of carburetor mounting bolts/nuts. Refer to Figures 6C2-A through 6C2-I for carburetor adjustment procedures and specifications. Checking Idle Solenoid 1. Turn on ignition, but do not start engine. 2. Open throttle to allow solenoid plunger to extend, close throttle. 3. Disconnect lead at solenoid. Solenoid plunger should drop away from throttle lever. 4. Connect solenoid lead. Plunger should move out and contact the throttle lever. Solenoid may not be strong enough to open the throttle, but the plunger should move. LIG H T T R U C K SERVIC E M A N U A L 5. If plunger does not move in and out as lead is discon­ nected and connected, insert test lamp (1893 bult or smaller) between the solenoid feed wire and ground. 6. If light lights, replace solenoid. 7. If light does not light, locate cause of open circuit in solenoid feed wire. IDLE SOLENOID REPLACEMENT An inoperative solenoid should be replaced. Removal 1. Remove carburetor air cleaner. 2. Disconnect electrical connector at solenoid. 3. Unscrew and remove solenoid from float bowl assembly. Installation 1. Hold choke valve wide open so that fast idle cam follower clears fast idle cam. 2. Install solenoid and turn in until it contacts lever tang. 3. Connect electrical connector. 4. Install air cleaner. 5. Check and adjust idle speed. CARBURETOR MODEL 2SE 6C2-5 2SE CARBURETOR ADJUSTMENTS FLOAT ADJUSTMENT HOLD RETAINER C j) GAUGE AT TOE OF FLOAT AT POINT FURTHEST AWAY FROM FLOAT HINGE PIN (SEE INSET). ^ REMOVE FLOAT AND BEND FLOAT ARM UP OR DOWN TO ADJUST ® PUSH FLOAT DOWN LIGHTLY AGAINST NEEDLE VISUALLY CHECK FLOAT ALIGNMENT AFTER ADJUSTING PUMP ADJUSTMENT NON-ADJUSTABLE Fig. 6C2-A--2SE Carburetor Adjustments LIG H T TR U C K SERVIC E M AN U AL 6C2-6 CARBURETOR MODEL 2SE 2SE CARBURETOR ADJUSTMENTS FAST IDLE ADJUSTMENT (TYPICAL) (BENCH SETTING) Q PLACE FAST IDLE SCREW ON HIGHEST STEP OF FAST IDLE CAM. „ T TURN FAST IDLE SCREW IN OR OUT TO JUST CONTACT CAM, THEN TURN SCREW IN SPECIFIED NUMBER OF TURNS. CHOKE COIL LEVER ADJUSTMENT (TYPICAL) © REMOVE RIVETS AND CHOKE © BEND INTERM EDIATE CHOKE ROD TO ADJUST COVER AND COIL ASSEMBLY FOLLOW ING INSTRUC TIO NS IN CHOKE STAT COVER ® PLACE FAST IDLE RETAINER KIT (SEE NOTE). SCREW ON H IG H STEP NOTE: DO NOT REMOVE OF FAST IDLE CAM .0 8 5 GAGEJi RIVETS AND RETAINERS HO LD IN G CHOKE COVER AND CO IL ASSEMBLY IN PLACE UNLESS NECESSARY TO CHECK THE CHOKE COIL LEVER ADJUSTM ENT. IF RIVETS AND COVER ARE REMOVED, A CHOKE STAT COVER RETAINER KIT IS REQUIRED FOR REASSEMBLY. EDGE OF LEVER SHO ULD JUST C O N T A C T SIDE OF PLUG G AG E AS SHOW N INSERT .0 8 5 PLUG G AG E INTO HOLE PROVIDED Fig. 6C2-B--2SE Carburetor Adjustments LIG H T T R U C K SERVICE M A N U A L PUSH ON IN T E R ­ M EDIATE CHOKE LEVER U N TIL CHOKE VALVE IS CLOSED CARBURETOR MODEL 2SE 6C2-7 2SE CARBURETOR ADJUSTMENTS FAS T IDLE CAM (CHOKE ROD) RELATION ADJUSTMENT - TYPICAL FIGURE 1 1. CHOKE COIL LEVER ADJUSTMENT MUST BE CORRECT AND FAST IDLE ADJUSTMENT MUST BE MADE BEFORE PROCEEDING. 2. USE CHOKE VALVE MEASURING GAUGE J-26701. TOOL MAY BE USED WITH CARBURETOR ON OR OFF ENGINE. IF OFF ENGINE, PLACE CARBURETOR ON HOLDING FIXTURE SO THAT IT WILL REMAIN IN SAME POSITION WHEN GAUGE IS IN PLACE. 3. ROTATE DEGREE SCALE UNTIL ZERO (0) IS OPPOSITE POINTER. 4. WITH CHOKE VALVE COMPLETELY CLOSED (NECESSARY FOR FAST IDLE SCREW TO BE ON HIGH STEP OF FAST IDLE CAM FOR INITIAL ZERO SETTING OF GAUGE). PLACE MAGNET SQUARELY ON TOP OF CHOKE VALVE. 5. ROTATE BUBBLE UNTIL IT IS CENTERED. FIGURE 2 6. ROTATE SCALE SO THAT DEGREE SPECIFIED FOR ADJUSTMENT IS OPPOSITE POINTER. 7. PLACE FAST IDLE SCREW ON SECOND STEP OF CAM AGAINST RISE OF HIGH STEP. 8. HOLD CHOKE VALVE TOWARD CLOSED POSITION BY LIGHTLY PUSHING ON INTERMEDIATE CHOKE LEVER. 9. TO ADJUST, BEND FAST IDLE CAM ROD UNTIL BUBBLE IS CENTERF.D. 10. REMOVE GAUGE. ^ ©DEGREE SCA LF LEVE LIN G BUBBLE (C E N T E R E D ) S P E C IF IE D A N G L E SEE SP EC S .) / B EN D RO D T O A D J U S T P O IN T E R MAGNET FIG U R E 1 HOLD C H O K E VALVE TOW ARD C L O S E D PO S ITIO N BY LIG H TLY PU S H IN G ON IN T E R ­ M E D IA T E C H O K E LEVER FIG U R E 2 PLACE FAST IDLE SCREW O N S E C O N D STEP OF C A M A G A IN S T RISE OF H IG H STEP FAST ID LE CAM FIG U R E 2 ® R E M 0V E GAUGE Fig. 6C2-C--2SE Carburetor Adjustments LIGHT TRUCK SERVICE MANUAL 6C2-8 CARBURETOR MODEL 2SE 2 S E CARBURETO R A D J U S T M E N T S PRIMARY SIDE VACUUM BREAK ADJUSTMENT NOTE: PRIOR TO A D JUSTM ENT, REMOVE PRIMARY VAC UUM BREAK FROM CARBURETOR. PLACE BRACKET IN A VISE AND, USING SAFETY PRECAUTIO N S, G R IN D OFF A D JU S TM EN T SCREW CAP. REINSTALL VACUUM BREAK. FIGURE 1 1. USE CHOKE VALVE M EASURING GAUGE J-26701 . TO O L MAY BE USED W ITH CARBURETOR ON OR OFF ENGINE. IF OFF ENGINE, PLACE CARBURETOR ON HO LD IN G FIXTURE SO TH A T IT WILL REMAIN IN SAME PO SITIO N WHEN G AUGE IS IN PLACE. 2. ROTATE DEGREE SCALE U N TIL ZERO (0) IS OPPO SITE POINTER. 3. W ITH CHOKE VALVE COM PLETELY CLOSED (FAST IDLE SCREW M UST BE ON H IG H STEP OF FAST IDLE CAM ), PLACE M AG NET SQUARELY ON TOP OF CHOKE VALVE. 4. ROTATE BUBBLE U NTIL IT IS CENTERED. FIGURE 2 5. ROTATE SCALE SO TH A T DEGREE SPECIFIED FOR AD JU S TM EN T IS O PPOSITE PO INTER. 6. SEAT CHOKE VAC UUM DIAPHRAGM USING VAC UUM SOURCE. OVER 5" HG. VACUUM M UST BE APPLIED TO VACUUM BREAK. ALSO, AIR VALVE ROD M UST N O T BE RESTRICTING VACUUM DIAPHRAG M FROM SEATING. IT MAY BE NECESSARY TO BEND AIR VALVE ROD TO O BTAIN A SLIG HT CLEARANCE BETWEEN ROD AND END OF SLOT IN AIR VALVE LEVER. PROCEED TO AIR VALVE ROD AD JU S TM EN T AFTER PRIMARY VACUUM BREAK ADJUSTM ENT. 7. DURING READING OF ANGLE GAUGE, HOLD CHOKE VALVE TOW ARD CLOSED P O S ITIO N BY LIG H TLY P USHING ON INTER M ED IA TE CHOKE LEVER. 8. TO ADJUST, USING 1/8" HEX W RENCH, TURN SCREW IN REAR COVER UNTIL BUBBLE IS CENTERED. APPLY SEALER (SUCH AS SILICO NE SEALANT RTV RUBBER OR EQ UIVALENT) OVER SCREW HEAD TO SEAL SETTING . 9. REMOVE GAUGE. FI G U R E 2 SILICONE SEALANT RTV RUBBER OR EQUIVALENT) OVER SCREW HEAD TO SEAL SETTING. Fig. 6C2-D--2SE Carburetor Adjustments LIGHT TRU CK SERVICE MANUAL CARBURETOR MODEL 2SE 6C2-9 2SE CARBURETOR ADJUSTMENTS AIR VALVE ROD ADJUSTMENT - TYPICAL ® © ROTATE Al« VALVE IN THE DIRECTION OF OPEN AIR VALVE BY APPLYING ALIGHT PRESSURE TO THE AIR VALVE SHAFT. © L E V E L IN G BUBBLE (CENTERED) ODEGREE SCALE SPECIFIED ANGLE (SEE SPECS.) AIR VALVE CLOSED \ POINTER MAGNET FIGURE 1 TO ADJUST, BEND AIR VALVE ROD UNTIL BUBBLE IS CENTERED. SEAT VACUUM DIAPHRAGM USING VACUUM SOURCE Fig. 6C2-E--2SE Carburetor Adjustments LIGHT TRUCK SERVICE MANUAL 6C2-10 CARBURETOR MODEL 2SE 2 S E CARBURETOR A D J U S T M E N T S SECONDARY VACUUM BREAK ADJUSTMENT FIG URE 1 1. REMOVE VACUUM BREAK FROM CARBURETOR. PLACE BRACKET IN A VISE AND, USING SAFETY PRECAUTIONS, G RIND OFF ADJUSTM ENT SCREW CAP. 2. PLUG END COVER USING AN ACCELERATOR PUMP PLUNGER CUP - VARAJET TYPE OR EQUIVALENT. CUP M UST BE REMOVED AFTER ADJUSTM ENT (SEE STEP 10, FIGURE 3) REINSTALL VACUUM BREAK. FIG UR E 2 3. USE CHOKE VALVE M EASURING GAUGE J-26701 . TO O L MAY BE USED W ITH CARBURETOR ON OR OFF ENG INE. IF OFF ENGINE, PLACE CARBURETOR ON HO LDING FIXTURE SO TH A T IT WILL REMAIN IN SAME PO S ITIO N WHEN GAUGE IS IN PLACE. 4. RO TATE DEGREE SCALE U NTIL ZERO (0) IS O PPOSITE POINTER. 5. W ITH CHOKE VALVE COM PLETELY CLOSED (FAST IDLE SCREW M UST BE ON HIG H STEP OF FAST IDLE CAM), PLACE M AGNET SQUARELY ON TOP OF CHOKE VALVE. 6. ROTATE BUBBLE U N TIL IT IS CENTERED. FIGURE 3 7. ROTATE SCALE SO TH A T DEGREE SPECIFIED FOR AD JU S TM EN T IS O PPOSITE POINTER. 8. SEAT CHO KE VAC UUM DIAPHRAGM USING VACUUM SOURCE. (AIR BLEED SEALED AND OVER 5" HG. VAC UUM ) 9. DU R IN G READING OF ANGLE GAUGE, HOLD CHOKE VALVE TOW ARD CLOSED PO SITIO N BY LIG HTLY PUSHING ON INTERM EDIATE CHOKE LEVER. MAKE SURE VACUUM DIAPHRAG M IS SEATED (OVER 5" HG. APPLIED TO VACUUM BREAK). 10. TO ADJUST, USING 1/8" HEX W RENCH, TURN SCREW IN REAR COVER U N T IL BUBBLE IS CENTERED. REMOVE CUP INSTALLED IN STEP 2 (FIG URE 1) AFTER ADJUSTM ENT. APPLY SEALER (SUCH AS SILICO NE SEALANT RTV RUBBER OR EQ UIVALENT) OVER SCREW HEAD TO SEAL SETTING . 11. REMOVE GAUGE. © S E A T D IA P H R A G M U S IN G V A C U U M S O U R C E . (A IR B L E E D S E A L E D A N D O V E R 5 ” H g V A C U U M ). SPECIFIED ANGLE (SEE SPECS.) © © ADJUSTMENT SCREW ACCESS (CAP REMOVED) bubble (C ENTERED ) © Ii PUMP © ;9 ) ' ©CHOKE / VALVE CLOSED ^ . ( F A S T IDLE SCREW MUST BE ON HIGH STEP OF FAST IDLE CAM) PLUNGER CUP ^ FIGURE 1 DURING READING OF ANGLE GAUGE, LIGHTLY PUSH CLOCKW ISE ON IN T E R ­ MEDIATE CHOKE w LEVER (IN DIRECTION T OF CLOSED CHOKE VALVE) AND HOLD IN POSITION WITH RUBBER BAND. FIGURE 3 rj ® TO ADJUST, USING 1 /8 ” HEX WRENCH, TURN SCREW IN REAR COVER UNTIL BUBBLE IS CENTERED. REMOVECUP INSTALLED IN STEP 2 (FIGURE 1) AFTER ADJUSTMENT. APPLY SEALER (SUCH AS SILICONE 'SEALANT RTV RUBBER OR EQUIVALENT) OVER SCREW HEAD TO SEAL SETTING. Fig. 6C2-F--2SE Carburetor Adjustments LIGHT TRUCK SERVICE MANUAL LEVELING CARBURETOR MODEL 2SE 6C 2-11 2SE CARBURETOR ADJUSTMENTS UNLOADER ADJUSTMENT (TYPICAL) 1. USE CHOKE VALVE MEASURING GAUGE J-26701 . TOOL MAY BE USED WITH CARBURETOR ON OR OFF ENGINE. IF OFF ENGINE, PLACE CARBURETOR ON HOLDING FIXTURE SO THAT IT WILL REMAIN IN SAME POSITION WHEN GAUGE IS IN PLACE. 2. ROTATE DEGREE SCALE UNTIL ZERO (0) IS OPPOSITE POINTER. 3. WITH CHOKE VALVE COMPLETELY CLOSED (NECESSARY FOR FAST IDLE SCREW TO BE ON HIGH STEP OF FAST IDLE CAM FOR INITIAL ZERO SETTING OF GAUGE), PLACE MAGNET SQUARELY ON TOP OF CHOKE VALVE. 4. ROTATE BUBBLE UNTIL IT IS CENTERED. FIGURE 2 5. ROTATE SCALE SO THAT DEGREE SPECIFIED FOR ADJUSTMENT IS OPPOSITE POINTER. 6. HOLD PRIMARY THROTTLE VALVE WIDE OPEN. 7. DURING READING OF ANGLE GAUGE: LIGHTLY PUSH CLOCKWISE ON INTERMEDIATE CHOKE LEVER (IN DIRECTION OF CLOSED CHOKE VALVE) AND HOLD IN POSITION WITH RUBBER BAND. 8. TO ADJUST, BEND TANG ON THROTTLE LEVER UNTIL BUBBLE IS CENTERED. 9. REMOVE GAUGE. 10. AT THIS POINT REINSTALL CHOKE COVER AND COIL ASSEMBLY (IF PREVIOUSLY REMOVED AND NOT REINSTALLED) FOLLOWING INSTRUCTIONS IN CHOKE STAT COVER RETAINER KIT (INCLUDES REPLACEMENT ATTACHING RIVETS). © L E V E L IN G V -T B U B B LE / J (C E N T E R E D ) © S P E C IF IE D A N G L E (S E E S P E C S .) " CHOKE V A LV E CLOSED BEND TANG TO A D J U S T U N T IL B U B B L E IS CENTERED. © D U R I N G R E A D IN G O F A N G L E G A U G E , L IG H T L Y P U S H C L O C K W IS E ON IN T E R M E D IA T E C H O K E LEVER (IN D IR E C T IO N O F C L O S E D C H O K E V A L V E ) A N D H O L D IN P O S IT IO N W IT H R U B B ER B A N D . ©V H O L D P R IM A R Y T H R O T T L E V A LV E W ID E O P E N Fig. 6C2-G--2SE Carburetor Adjustments LIGHT TRUCK SERVICE MANUAL 6C2-12 CARBURETOR MODEL 2SE 2S E CARBURETO R A D J U S T M E N T S SECONDARY LOCKOUT ADJUSTMENT O IF NECESSARY TO ADJUST, BEND LOCKOUT LEVER TANG CONTACTING FAST IDLE CAM. HOLD CHOKE VALVE WIDE OPEN BY PUSHING COUNTER­ CLOCKWISE ON INTERMEDIATE CHOKE LEVER. GAUGE CLEARANCE D IMENSION SHOULD BE AS SPECIFIED. OPEN THROTTLE LEVER UNTIL END OF SECONDARY ACTUATING LEVER IS OPPOSITE TOE OF LOCKOUT LEVER. FAST IDLE ADJUSTMENT (ON VEHICLE] © PREPARE VEHICLE FOR ADJUST­ MENTS - SEE EMISSION LABEL ON VEHICLE. NOTE: IG N ITIO N TIM IN G SET PER LABEL. © TURN FAST IDLE SCREW IN OR O UT TO OBTAIN SPECIFIED FAST IDLE R.P.M. - (SEE LABEL) PLACE FAST IDLE SCREW ON HIGHEST STEP OF FAST IDLE CAM IDLE SPEED ADJUSTMENT (ON VEHICLE) O PREPARE VEHICLE FOR ADJUSTMENTS SEE EMISSION LABEL ON VEHICLE. NOTE: IG N ITIO N TIM IN G SET PER LABEL. © SOLENOID ENERGIZED - A /T IN DRIVE, M /T IN NEUTRAL © © TURN IDLE SPEED SCREW TO SET BASIC IDLE SPEED TO SPECIFICATIONS (SOLENOID DE-ENERGIZED) RECONNECT SOLENOID ELECTRICAL LEAD AFTER ADJUSTMENT TURN SOLENOID SCREW TO ADJUST CURB IDLE SPEED TO SPECIFIED RPM (SOLENOID ENERGIZED) Fig. 6 C 2 -H —C a rb u re to r Adjustments LIGHT TRUCK SERVICE MANUAL OPEN THROTTLE SLIGHTLY TO ALLOW SOLENOID PLUNGER TO FULLY EXTEND NOTE: FUEL LEVEL MAY BE AFFECTED BY FUEL PUMP PRESSURE AS WELL AS BY FLOAT LEVEL ADJUSTMENT. © REMOVE AIR HORN SCREW ( 4) READING AT EYE LEVEL, OBSERVE MARK ON GAUGE THAT LINES UP WITH TOP OF CASTING AT THE VENT HOLE. SETTING SHOULD BE WITHIN ±1.5mm FROM SPECIFIED FLOAT LEVEL SETTING. /T \ REMOVE VENT STACK SCREWS > 1 / AND VENT STACK WITH ENGINE RUNNING AT IDLE, CHOKE WIDE-OPEN, CAREFULLY INSERT GAUGE IN AIR HORN SCREW HOLE WITH SCALE IN VENT HOLE. RELEASE GAUGE AND ALLOW IT TO FLOAT FREELY. REMOVE FLOAT GAUGE FROM AIR HORN ( 5) IF THE MECHANICAL SETTING (STEP 4) VARIES MORE THAN ±1.5mm FROM SPECIFICATIONS, REMOVE AIR HORN AND ADJUST FLOAT LEVEL TO SPECIFI­ CATIONS FOLLOWING NORMAL ADJUSTMENT PROCEDURES. © I F MECHANICAL SETTING IS FOUND TO BE WITHIN SPECIFIED TOLERANCE - REPLACE AIR HORN SCREW, VENT STACK AND VENT STACK SCREWS. CAUTION: DO NOT PRESS DOWN ON GAUGE TO CAUSE FLOODING OR DAMAGE TO FLOAT. SELECT GAUGE TO MATCH CARBURETOR SERIES BEING CHECKED TOOL J-9789-135 BLUE - 1979-81 2SE RED - 1979 1/2-80 E2SE WHITE - 1981 E2SE FLOAT GAUGE - EXTERNAL CHECKING PROCEDURE (2SE - E2SE TYPICAL) 6C2-14 CARBURETOR MODEL 2SE CHECKING ELECTRIC CHOKE 1. Remove air cleaner. W ith engine off, hold throttle half open. O pen and close choke several tim es. W atch linkage to be certain all links are connected and there are no signs of dam age or binding. 2. If choke or linkage binds, sticks or works sluggishly due to petroleum gum form ation, clean with choke cleaner or equivalent. Use cleaner as directed on can. 3. Allow choke to cool so th at when throttle is opened slightly, choke blade fully closes. This check should be m ade at an am bient tem perature of 15° to 27°C (59° to 80°F). 4. S ta rt engine and determ ine tim e for choke blade to reach full open position. (S ta rt tim er when engine starts.) 5. If choke blade fails to open fully within 3-1/2 minutes, open throttle about 1/3. If choke still fails to open fully, proceed with steps 6 and 7. 6. Check voltage at the choke heater connection: (Engine m ust be running). a. If the voltage is approxim ately 12-15 volts, replace the electric choke unit. b. If the voltage is low or zero, check all wires and connections. If any connections in the oil pressure sw itch c irc u itry are faulty or if the oil pressure switch is failed open, the oil pressure w arning light will be on with engine running. R epair wires or connections as required. 7. If steps 4a and 4b do not correct problem, replace oil pressure switch. No gasket is used between the choke cover and the choke housing due to grounding requirem ents. 8. Reinstall air cleaner. CHOKE COIL REPLACEMENT Choke m echanism should be checked for free opera­ tion. A binding condition may have developed from petro­ leum gum form ation on the choke shaft or from dam age. Choke shafts can usually be cleaned without disassembly. 1. Remove air cleaner and disconnect choke electrical connector. 2. Align a # 2 1 drill (.1 5 9 ") on rivet head and drill only enough to remove rivet head. A fter removing rivet LIGHT TRUCK SERVICE MANUAL 3. 4. 5. 6. heads and retainers, use a draft and small ham m er to drive the rem ainder of the rivets out of the choke housing. Use care in drilling to prevent dam age to the choke cover or housing. Remove the three retainers and choke cover assembly from choke housing. Remove choke coil from housing. Install the choke cover and coil assembly in choke housing as follows: a. Install the choke cover and coil assembly in the choke housing, aligning notch in cover with raised casting projection on housing cover flange. M ake sure coil pick-up tang engages the inside choke coil lever. A choke cover retainer kit is required to attach the choke cover to the choke housing. Install proper retainers and rivets contained in kit using a suitable blind rivet installing tool. It may be necessary to use an adapter (tube) if installing tool interferes with electrical connector tower on choke cover. Connect choke electrical connector. S ta rt engine, check operation of choke and then install air cleaner. Idle Mixture Check and Adjustment (Propane Enrichment) Idle m ixture screws have been present at the factory and sealed. Idle m ixture should be adjusted only in the case of m ajor carburetor overhaul, th rottle body replacem ent or high emissions as determ ined by offical inspections. A djust­ ing m ixture by other than the following method may violate Federal an d /o r California or other state or provincial laws. Because of the sealed idle m ixture screws, the idle m ixture checking procedure requires artificial enrichm ent by adding propane. 1. Set parking brake and block drive wheels. On cars equipped with vacuum parking brake release, discon­ nect and plug hose at brake. Engine must be at normal operating tem perature and air conditioning off. 2. Disconnect and plug hoses as directed on the Emission Control Inform ation Label under the hood. 3. Connect an accurate tachom eter to engine. 4. Disconnect vacuum advance and set tim ing to specifi­ cation shown on the Emission Control Inform ation Label. Re-connect vacuum advance. CARBURETOR MODEL 2SE 6C 2-15 5. Set carburetor idle speed to specification as shown on Emission C ontrol Inform ation Label. 6. Disconnect crankcase ventilation tube from air cleaner. 7. Using tool J-26911, insert hose with rubber stopper, from propane valve into crankcase ventilation tube opening in air cleaner. P ro p an e c a rtrid g e m ust be vertical. 8. W ith engine idling in drive (neutral for m anual shifts) slowly open propane control valve while pressing button. C ontinue to add propane until speed drops due to over richness. N ote m axim um engine speed (en­ riched speed). If rich speed drop cannot be obtained check for em pty cartridge or propane system leaks. 9. If the enriched idle speed is within the enriched idle specification the m ixture is correct. Go to step 17. 10. If the enriched idle speed is not within specifications, remove m ixture screw plugs following procedures. 11. Lightly seat screws, then back out equally, ju st enough so engine will run. 12. Place transm ission in Drive (autom atics) or N eutral (m anuals). 13. Back each screw out (richen 1/8 turn at a tim e until m axim um idle speed is obtained). Then set idle speed to the enriched idle specification. 14. T urn each m ixture screw in (clockwise) 1/8 turn at a tim e until idle speed reaches value given on Emission Control Inform ation Label. 15. Recheck enriched speed with propane. If not within specification, repeat adjustm ent beginning with Step 12 . 16. Check and adjust fast idle as described on Emission Control Inform ation Label. 17. T urn off engine. Remove propane tool, connect crank­ case ventilation tube. Re-connect vacuum hoses. Carburetor Mounting Torque W hen torquing carburetor after removed, overhaul, replacem ent or when installing a new heat insulator, torque m ounting bolts in a clockwise direction to 23 N-m (198 in. lbs.). W hen retorquing carburetor at recom m ended m ainte­ nance intervals, retorque to 16 N-m (144 in. lbs.) maxim um . CARBURETOR REPLACEMENT (FIG. 6C2-3a) Removal Flooding, stum ble on acceleration and other perform ­ ance com plaints are, in many instances, caused by presence of dirt, w ater, or other foreign m atter in carburetor. To aid in diagnosing cause, carburetor should be carefully removed from engine w ithout draining fuel from bowl. Contents of fuel bowl may then be examined for contamination as carburetor is disassembled. Check filter. 1. Remove air cleaner. 2. Disconnect fuel and vacuum lines from carburetor. 3. Disconnect electrical connector at choke. 4. Disconnect accelerator linkage and transmission cable. 5. Disconnect solenoid electrical connector. 6. Remove carburetor attaching nuts and remove car­ buretor and solenoid assembly attachment. 7. Remove insulator gasket. Installation It is good shop practice to fill carburetor bowl before installing carburetor. This reduces strain on starting motor and battery and reduces the possibility of backfiring while attempting to start engine. A small supply of fuel will enable carburetor to be filled and the operation of float and intake needle and seat to be checked. Operate throttle lever several times and check discharge from pump jets before installing carburetor. 1. Be certain throttle body and intake manifold sealing surface are clean. 2. Install carburetor insulator. 3. Install carburetor over manifold studs. 4. Install vacuum and fuel lines at carburetor. 5. Install attaching nuts and tighten alternately to 21 N-m (16 ft. lbs.). 6. Tighten fuel line. 7. Connect accelerator linkage and transmission cable. 8. Connect choke and solenoid electrical connectors. 9. Install air cleaner. 10. Check and adjust idle speed. UNIT REPAIR The procedures below apply to the com plete overhaul with the carburetor removed from the engine. However, in m any cases service adjustm ents of individual systems may be com pleted without removing the carburetor from the engine (refer to On-Car Service). A complete carburetor overhaul includes disassembly, thorough cleaning, inspec­ tion, and replacement of all gaskets - diaphragms - seals LIGHT TRUCK SERVICE MANUAL 6C2-16 CARBURETOR MODEL 2SE worn or dam aged parts, and service adjustm ent of individual systems. CARBURETOR DISASSEMBLY Before perform ing any service on the carburetor, it is essential th at the carburetor be placed on a holding fixture such as tool J-9 7 8 9 -1 18 or equivalent. W ithout the use of the holding fixture, it is possible to dam age throttle valves. Idle Speed Solenoid Removal 1. Bend back retaining tabs on lockwasher; then remove large solenoid retaining nut using suitable wrench. Use care in removing nut with wrench to avoid bending or dam ag in g choke linkage, solenoid b rack et, vacuum break unit or throttle lever. 2. Remove lockwasher and solenoid unit from bracket. T he solenoid should not be imm ersed in any type of c a rb u re to r cleaner and should alw ays be removed before com plete carburetor overhaul. Im m er­ sion in cleaner will dam age solenoid. NOTICE: Air Horn 1. Remove clip from hole in pump lever. Do not remove pump lever retaining screw or pum p lever from air horn assembly. 2. Rem ove hose from prim ary side vacuum break assembly. 3. Rem ove (2) screws securing p rim ary side vacuum break bracket to air horn (Fig. 6C2-3b); then, rotate vacuum break and b rack et assem bly to disengage vacuum break link from slot in vacuum break and choke lever and air valve rod from slot in air valve lever. N O TIC E: Do not place vacuum break assem bly in carburetor cleaner. Immersion in cleaner will dam age vacuum break diaphragm . 4. If necessary to replace the vacuum break rod or air valve rod, remove and discard retaining clips from end of air valve rods. New retaining clip is required for INTERMEDIATE CHOKE reassembly. Remove plastic bushing used on rods and retain for later re-use. 5. Remove secondary side idle speed solenoid-vacuum break b racket a ttac h in g screws from th ro ttle body (Fig. 6C2-3b). Then, rotate bracket to remove second­ ary side vacuum break link from slot in break and choke lever. 6. Remove and discard retaining clip from interm ediate choke rod at choke lever (Fig. 6C2-4). A new retaining clip is required for reassembly. Remove choke rod and plastic bushing from choke lever, and save the bushing for later re-use. 7. Remove (2) sm all screws th a t retain the hot idle com pensator valve (Fig. 6C2-5). Remove valve and seal from air horn. Discard seal. Hot idle com pensator valve m ust be removed to gain access to short air horn to bowl attaching screw. 8. Remove the seven (7) air horn to bowl attaching screws and lockwashers (Fig. 6C 2-6). Remove vent and screen assembly. 9. R otate fast idle cam to the full U P position and remove air horn assembly by tilting to disengage fast idle cam and pum p rod from hole in pump lever (Fig. 6C2-7). If pum p plunger came out of float bowl with air horn removal, remove pump plunger from air horn. The air horn gasket should rem ain on the float bowl for removal later. Do not remove fast idle cam screw and cam from float bowl. These parts are not serviced separately and are to rem ain perm anently in place as installed by the factory. The new service replacem ent float bowl will include the secondary lock-out lever, fast idle cam and screw installed as required. 10. Remove fast idle cam rod from choke lever by rotating rod to align squirt on rod with small slot in lever. Air Horn Disassembly 1. Remove pump plunger stem seal by inverting air horn and use a small screwdriver to remove staking holding the seal retainer in place. Remove and discard retainer and seal. VACUUM BREAK AND CHOKE LEVER LINK (SECONDARY SIDE V A C U U M BREAK) CUP AIR VALVE ROD BREAK CHOKE LEVER LO CATING LUG VALVE LEVER BRACKET AT TAC H IN G SCREWS SECONDARY SIDE VACUUM PR IM AR Y SIDE V A C U U M BREAK LINK (PRIM ARY SIDE V A C U U M BREAK! BRACKET A TTAC H IN G SCREWS Fig. 6C2-3b--Vacuum Break and Idle Speed Solenoid LIGHT TRUCK SERVICE MANUAL IDLE SPEED SOLENOID Fig. 6C2-4--Choke Rod and Choke Lever CARBURETOR MODEL 2SE 6C 2-17 H O T IDLE Fig. 6C2-5--Hot Idle Compensator Fig. 6C2-7--Air Horn Assembly 2. F urth er disassembly of the air horn is not required for cleaning purposes or air horn replacem ent. The new service a ir horn assem bly includes the secondary m etering rod-air valve assembly and is pre-set at the factory. N o attem pt should be m ade to change this adjustm ent in the field. The air valve and choke valve screws are perm anently staked in place and should not be removed. Float Bowl Disassembly 1. Remove air horn gasket. G asket is pre-cut for easy removal around m etering rod and hanger assembly. 2. Remove pump plunger from pum p well. 3. Remove pump return spring from pum p well. 4. Remove plastic filler block over float valve. 5. Remove float assembly and float valve by pulling up on retaining pin. Remove float valve seat and gasket, using a wide blade screwdriver th a t fully fits the slots on top of the float valve seat. 6. Remove power piston and m etering rod assembly by depressing piston stem and allowing it to snap free (Fig. 6C2-8). The power piston can be easily removed by A IR H O R N S C R E W S - a id lio d k i pressing the piston down and releasing it with a snap. This will cause the power piston spring to snap the piston up against the plastic retainer. This procedure may have to be repeated several times. Do not remove power piston by using pliers on m etering rod holder. 7. Remove the power piston spring from the piston bore. If necessary, m etering rod may be removed from power piston hanger by compressing spring on top of m etering rod and aligning groove on rod with slot in holder. Use extrem e care in handling the m etering rod to prevent dam age to m etering rod tip. 8. Remove the m ain m etering jet using a wide blade screwdriver th at fully fits the slot in top of the jet (Fig. 6C2-8). 9. Using a small slide ham m er or equivalent, remove plastic retainer holding pump discharge spring and check ball in place (Fig. 6C 2-10). D iscard plastic retainer (a new retainer is required for reassem bly). T urn bowl upside down catching pum p discharge spring and check ball in palm of hand. Do not attem pt to remove plastic retainer by prying out with a tool such as a punch or screwdriver this will dam age the sealing beads on the bowl casting surface requiring com plete float bowl replacem ent. NOTICE: c r o c u /c Choke Disassembly Fig. 6C2-6--Air Horn Screws 1. Support float bow and throttle body as an assembly on a suitable holding fixture such as Tool J-9789-1 18. Align a # 2 1 drill (.1 5 9 ") on rivet head and drill only enough to remove rivet head (Fig. 6C 2-11). D rill the two rem aining rivet heads and then use a drift and small ham m er to drive the rem ainder of the rivets out of the choke housing. Use care to prevent dam age to choke cover or housing. 2. Remove the choke cover assembly from choke housing. 3. Remove screw from end of interm ediate choke shaft inside choke housing. Remove choke coil lever from shaft. 4. Remove interm ediate choke shaft and lever assembly from float bowl by sliding rearw ard out throttle lever side (Fig. 6C2-12). LIGHT TRUCK SERVICE MANUAL 6C2-18 CARBURETOR MODEL 2SE PUMP DISCHARGE SPRING AND BALL RETAINER POWER RETAINER MAIN METERING ROD MAIN METERING JET Fig. 6C2-10--Pump Discharge Spring and Ball Fig. 6C2-8--Power Piston and Metering Rod Assembly 5. Remove choke housing by removing two (2) attaching screws in throttle body (Fig. 6C2-13). Rivets and Retainers Disassembly of Rem aining Float Bowl Parts 1. Remove/fuel inlet nut, gasket, check valve filter assem­ bly, and spring. 2. Remove (4) throttle body to bowl attaching screws and lockwashers and remove throttle body assembly (Fig. 6C2-14). 3. Remove throttle body to bowl insulator gasket. Throttle Body Disassem bly Place throttle body assembly on carburetor holding fixture to avoid damaging throttle valves. Fig. 6C2-11--Riveted Choke Cover S P R IN G R E T A IN E R HOLDER GROD R E T A IN E R PO W ER P IS T O N INTERMEDIATE CHOKE SHAFT AND LEVER ASSEMBLY Fig. 6C2-9~Power Piston Assembly LIGHT TRUCK SERVICE MANUAL Fig. 6C2-12--Choke Shaft and Lever Assembly CARBURETOR MODEL 2SE 6C 2-19 Remove idle m ixture needle and plug as follows (Fig. 6C2-15): a. Invert throttle body and place on carburetor holding fixture-manifold side up. b. M ake two parallel cuts in throttle body on either side of the locator points beneath the idle m ixture needle plug (manifold side) with a hack saw. The cuts should reach down to the steel plug but should not extend more than 1/8" beyond the locator points. The distance between the saw m arks depends on the size of the punch to be used. c. Place a flat punch at a point near the ends of the saw m arks in the throttle body. Holding the punch at a 45 degree angle, drive it into the throttle body until the casting breaks away, exposing the steel plug. d. Holding a center punch vertical, drive it into the steel plug. Then, holding the punch at a 45 degree angle, drive the plug out of the casting. H ardened plug will sh a tte r ra th e r th a n rem aining intact. It is not necessary to remove the plug com ­ pletely; instead, remove loose pieces to allow use of Idle M ixture A djusting Tool J-29030. Fig. 6C2-13--Choke Housing Screws 1. Hold prim ary throttle lever wide-open and disengage pum p rod from throttle lever by rotating rod until squirt on rod aligns with slot in lever. 2. If replacem ent is necessary, remove fast idle screw and clip in prim ary throttle lever. 3. F u rth er disassembly of the thro ttle body is not required for cleaning purposes. T he p rim ary and secondary throttle valve screws are perm anently staked in place and should not be rem oved. T he th ro ttle body is serviced as a complete assembly. 4. DO N O T R E M O V E plugs covering idle m ixture needle unless it is necessary to replace the m ixture needle or norm al soaking and air pressure fails to clean the idle m ixture passages. Idle m ixture should be adjusted only if required at time of m ajor carburetor overhaul, throttle body replace­ m ent, or high em issions as d eterm in ed by offical inspections. THROTTLE BODY ** ATTACHING SCREWS v e. Using Tool J-29030, remove idle m ixture needle and spring from throttle body. f. Using Tool J-29030-B, remove idle m ixture needle, and spring from throttle body. CLEANING AND INSPECTION T he c a rb u re to r p arts should be cleaned in a cold im mersion-type cleaner such as C arbon X (X -55) or its equivalent. The solenoid, electric choke, rubber parts, plastic parts, diaphragm s, pump plunger, plastic filler block should N O T be immersed in carburetor cleaner as they will swell, harden or distort. NOTICE: 1. Thoroughly clean all m etal parts and blow dry with com pressed air. M ake sure all fuel passages and m etering parts are free of burrs and dirt. Do not pass drills or wires through jets and passages. 2. Inspect upper and lower surface of carburetor castings for dam age. 3. Inspect holes in levers for excessive wear or out of round conditions. If worn, levers should be replaced. Inspect plastic bushings for dam age and excessive wear. Replace as required. 4. Check, repair, or replace parts if the following prob­ lems are encountered: A.Flooding 1. Inspect float valve and seat for dirt, deep wear grooves, scores, and proper seating. 2. Inspect float valve pull clip for proper installation (Fig. 6C2-16). Be careful not to bend pull clip. Fig. 6C2-14--Throttle Body Screws 3. Inspect float, float arm s and hinge pin for distor­ tion, binds, and burrs. Check density of m aterial in the float; if heavier than norm al, replace float. 4. Clean or replace fuel inlet filter and check valve assembly. B. Hesitation LIGHT TRUCK SERVICE MANUAL 6C2-20 CARBURETOR MODEL 2SE FLAT PUNCH CENTER PUNCH STEP#2 STEP #1 LOCATOR p 0 |N T \ HACKSAW RECESSED IDLE MIXTURE NEEDLE AND PLUG LOCATION Fig. 6C2-15—Idle Mixture Needle 1. Inspect pump plunger and cup for cracks, scores, or cup excessive wear. A used pum p cup will shrink when dry. If dried out, soak in fuel for 8 hours before testing. 2. Inspect pum p d u ratio n and retu rn springs for being weak or distorted. 3. Check all pum p passages and je t for dirt, im proper seating of discharge check ball and scores in pump well. Check condition of pump discharge check ball spring. 4. Check pump linkage for excessive wear; repair or replaceas necessary. C .H ard S tarting - Poor Cold O peration 1. Check choke valve and linkage for excessive wear, binds or distortion. 2. Inspect choke vacuum diaphragm s for leaks. 3. Clean or replace carburetor fuel filter. 4. Inspect float valve for sticking, dirt, etc. 5. Also check items under " Flooding". D.Poor Perform ance - Poor Gas Mileage 1. Clean all fuel and vacuum passages in castings. 2. Check choke valve for freedom of movement. 3. Check power piston, m etering rod, and jet for dirt, sticking, binding, d am aged p arts or excessive wear. LIGHT TRUCK SERVICE MANUAL 4. Check air valve and secondary metering rod for binding conditions. If air valve or m etering rod is dam aged, the air horn assembly must be replaced. Also, check air valve spring for proper installation (tension against air valve lever) E.Rough Idle 1. Inspect gasket and gasket m ating surfaces on castings for dam age to sealing beads, nicks, burrs and other dam age. 2. Clean all idle fuel passages. 3. If removed, inspect idle m ixture needle for ridges, burrs, or being bent. 4. Check throttle lever and valves for bind, nicks and other dam age. 5. C heck all d iaphragm s for possible ru p tu res or leaks. 6. C lean plastic p arts only in S to d d ard solvent never in gasoline. CARBU RETO R A SSEM B LY Throttle Body 1. Holding prim ary throttle lever wide open, install lower end of pump rod in throttle lever by aligning squirt on CARBURETOR MODEL 2SE 6C2-21 HOOK CLIP OVER EDGE OF FLAT ON FLOAT ARM FACING FLOAT PO N TO O N C A U TIO N : DO N O T HO O K PULL CLIP IN THESE HOLES FLOAT AND LEVER ASSEMBLY FLOAT NEEDLE PULL CLIP LOCATION ________________________________ (VARAJET II)______________________________ _ Fig. 6C2-16-Pull Clip Location rod with slot in lever. End of rod should point outw ard tow ard throttle lever. 2. If removed, install idle m ixture needle and spring using tool J-29030-B Lightly seat needle and then back out 3 turns as a prelim inary idle m ixture adjustm ent. Final idle m ixture adjustm ent m ust be made on-car using the procedure described under Idle M ixture A djustm ent. Float Bowl Assem bly T H R O T T L E B OD Y TO B O W L G A SK ET If a new float bowl assembly is used, stam p or engrave the model num ber on the new float bowl. 1. Install new throttle body to bowl insulator gasket over two locating dowels on bowl (Fig. 6C2-17). 2. Holding fast idle cam so th at cam steps face fast idle screw on throttle lever when properly installed, install throttle body making certain throttle body is properly located over dowels on float bowl; then install (4) th ro ttle body to bowl screws and lockw ashers and tighten securely (Fig. 6C2-14). Inspect linkage to insure lockout tan g is located properly to engage slot in secondary lockout lever and th a t linkage moves freely and does not bind. 3. Place carburetor on proper holding fixture such as J-9789-1 18 or equivalent. 4. Install fuel inlet filter spring, check valve filter assem ­ bly, new gasket and inlet nut and tighten nut to 24 N-m Fig. 6C2-17--Throttle Body to Bowl Gasket 6C2-22 5. 6. 7. 8. 9. 10. 11. 12. 13. CARBURETOR MODEL 2SE (18 ft. lbs.). Tightening beyond specified torque can dam age nylon gasket and cause fuel leak. W hen installing a service replacem ent filter, make sure the filter is the type th at includes the check valve to m eet U .S. M otor V ehicle S afety S ta n d ard s (M .V .S.S.). W hen properly installed,hole in filter faces toward inlet nut. Ribs on closed end of filter element prevent filter from being installed incorrectly unless forced. Install choke housing on throttle body, m aking sure raised boss and locating lug on rear of housing fit into recesses in float bowl casting (Fig. 6C 2-13). Install (2) choke housing attaching screws and lockwashers in throttle body and tighten screws evenly and securely. Install interm ediate choke shaft and lever assembly in float bowl by pushing through from throttle lever side (Fig. 6C2-12). W ith interm ediate choke lever in the U P (12 o’clock) position, install therm ostatic coil lever inside choke housing onto flats on interm ediate choke shaft. Coil is properly aligned when the coil pick-up tang is at the top (12 o’clock) position. Install inside lever retaining screw into end of interm ediate choke shaft and tighten securely. Do not install th e rm o sta tic choke cover and coil assembly in housing until inside coil lever is adjusted (see A djustm ents). Install pum p discharge steel check ball and spring in passage next to float cham ber (Fig. 6C2-10). Insert end of new plastic retainer into end of spring and install retainer in float bowl, tapping lightly in place until top of retainer is flush with bowl casting surface. Using a wide-blade screwdriver th a t fully fits the slot in the top, install m ain m etering je t and the float valve seat (with gasket) into bottom of float bowl. Tighten jet and seat securely (Fig. 6C2-26). To m ake adjustm ent easier, carefully bend float arm upward at notch in arm before assembly. Install float valve onto float arm by sliding float lever under pull clip. C orrect installation of the pull clip is to hook the clip over the edge of the float on the float arm (Fig. 6C2-16). Install float retaining pin into float arm with end of loop of pin facing pum p well. Then, install float assembly by aligning valve in the seat and float retaining pin into locating channels in float bowl. A djust float level as follows: a. Hold float retaining pin firmly in place and push down lightly on float arm at outer end against top of float needle. b. Using adjustable " T " scale, m easure from top of float bowl casting surface (air horn gasket removed) to top of float at toe (See inset, Float A djustm ent Fig. 6C 2-A ). c. Bend float arm as necessary for proper adjustm ent by pushing on pontoon (see specifications). d. Visually check float alignm ent after adjustm ent. 14. Install power piston spring into piston bore. 15. If removed, assemble m etering rod to holder on power piston. Spring m ust be on top of arm when assembled correctly (Fig. 6C2-9). 16. Install power piston and m etering rod assembly into the float bowl and main m etering jet. Use care installing the m etering rod into the jet to prevent dam aging the m etering rod tip. Press down firmly on plastic power piston retainer to make sure the retainer is seated in recess in bowl and the top is flush with the top of the bowl casting. If necessary, tap retainer lightly in place using a drift and small ham m er. 17. Install plastic filler block over float valve, pressing dow nw ard until properly seated (flush w ith bowl casting surface). 18. Install air horn gasket on float bowl by carefully sliding slit portion of gasket over the two dowel locating pins on the float bowl. 19. Install pump return spring in pum p well. 20. Install pump plunger assembly in pump well. Air Horn Assembly 1. Install new pum p plunger stem seal and retainer in air horn casting. Lightly stake seal retainer in three places, choosing locations different from the original stakings. 2. Install fast idle cam rod in lower hole of vacuum break and choke lever, aligning squirt on rod with small slot in lever (squirt end of rod points inward toward air horn). Air Horn To Bowl Installation 1. R otate fast idle cam to the full U P position and tilt the air horn assembly to engage lower end of fast idle cam rod in slot in fast idle cam and install pump rod end into hole in pump lever (Fig. 6C2-24). Then, holding down on the pump plunger assembly, carefully lower air horn assembly onto float bowl, guiding pump plunger stem through hole in air horn casting. Do not force air horn assembly onto bowl, but rath er lightly lower in place. 2. Install vent and screen assembly over vent stack in air horn Then, install (7) air horn to bowl attaching screws and lockwashers. following proper installation location and tightening sequence. All air horn screws must be tightened evenly and securely. See Fig. 6C2-18 for proper tightening sequence. 3. Install new retainer clip through hole in end of pump rod extending through pum p lever, making sure clip is securely locked in place. 4. Install new seal in recess of air horn, then install hot idle com pensator valve and retain w ith (2) sm all attaching screws. Tighten screws securely (Fig. 6C211). 5. Install plastic bushing in upper hole in vacuum break and choke lever, m aking sure small end of bushing faces retaining clip when installed. W ith inner coil lever and interm ediate choke lever at the 12 o’clock position, install interm ediate choke rod in bushing. R etain rod with new clip, pressing clip securely in place with needlenose pliers (Fig. 6C2-10). M ake sure clip has full contact on rod but is not seated tightly against bushing. Rod to bushing clearance should be ,8mm (.030"). CARBURETOR MODEL 2SE 6C2-23 "TRAPPED S T A T ” COIL AIR HORN SCREW TIGHTENING SEQUENCE (VARAJET - TYPICAL) Fig. 6C2-18--Air Horn Tightening Sequence 6. Install idle speed solenoid, lockwasher and retaining nut on secondary side vacuum break (Fig. 6C2-3). Tighten nut securely. Then, bend back two (2) retain­ ing tabs on lockwasher to fit slots in bracket. 7. R o tate secondary side vacuum break and bracket assembly and insert end ( " T " pin) of vacuum break link into upper slot of vacuum break and choke lever. Install bracket on throttle body and install countersunk screws. Tighten screws securely (Fig. 6C2-3). 8. If air valve rod has been removed from prim ary side vacuum break plunger, install plastic bushings in holes in prim ary side vacuum break plunger, making sure small end of bushings face retaining clips when in­ stalled. Then install vacuum break rod in upper hole of plunger and air valve rod in lower hole of plunger and secure new clips to rods using tool J-28697 or needle­ nosed pliers. R etaining clip is "d ish ed ". Install clip on rod with outw ard bend of self-locking clip facing end of rod. Check th at clips fully engage rods and th at clip is not distorted. 9. R otate prim ary side vacuum break and bracket assem ­ bly and insert end of air valve rod into slot of air valve lever and end of ( " T " pin) of vacuum break link into lower slot of vacuum break and choke lever. Position bracket over locating lug on air horn and install (2) countersunk screws and tighten securely (Fig. 6C2-3). 10. Reinstall hose to prim ary side vacuum break assembly and throttle body. 11. A fter completion of final choke coil lever adjustm ent (refer to C arburetor A djustm ents), install choke cover and coil assembly as follows: a. Install the choke cover and coil assembly in the choke housing, aligning notch in cover with raised Fig. 6C2-19--Trapped Stat Choke Cover casting projection on housing cover flange. M ake sure choke coil lever is located inside the "trapped sta t" coil tang when installing the choke cover and coil assembly (Fig. 6 C 2 -19). G round contact for the electric choke is provided by a metal plate located at the rear of the choke cover assembly. Do not install a choke cover gasket between the electric choke assembly and the choke housing. b. A choke cover retainer kit is required to attach choke cover to choke housing. Install proper retain ers and rivets contained in kit, using a suitable blind rivet installing tool (Fig. 6C2-20). It may be necessary to use an a d ap te r (tu b e) if installing tool interferes with electrical connector tower on choke cover (Fig. 6C2-21). Fig. 6C2-20~Rivet Installation LIGHT TRUCK SERVICE MANUAL 6C2-24 CARBURETOR MODEL 2SE 3 /1 6 ” ADAPTER (P ro c u re s te e l tu b in g lo c a lly ) Fig. 6C2-21 --Rivet Installation-Adapter LIGHT TRUCK SERVICE MANUAL CARBURETOR NUMBER FLOAT LEVEL PUMP SETTING m m /ln c h m m /ln c h FAST IDLE CAM (CHOKE ROD) AIR VALVE ROD VAC. BREAK PRI. VAC. BREAK UNLOADER SEC. Fig. 6C2-22--Adjustment Specifications 17081621 4.5 3/16 15.5 5 /8 15° 1° 26° 38° 17081622 .4 .5 3/16 15.5 5/8 15° 1° 26° 38° 38° 17081623 4.5 3/16 15.5 5/8 15° 1° 26° 38° 38° 170811624 4.5 3/16 15.5 5/8 15° 1° 26° 38° 38° 17081625 4.5 3/16 15.5 5/8 15° 1° 26° 38° 38° 17081626 4.5 3/16 15.5 5/8 15° 1° 26° 38° 17081627 4.5 3/16 15.5 5 /8 15° 1° 26° 38° 38° 38° 17081629 3/16 3/16 3/16 15.5 5/8 15° 1° 24° 34° 41° 15.5 5/8 15° 1° 26° 38° 38° 17081633 4.5 4.5 4.5 15.5 5/8 15° 1° 26° 38° 38° 17081720 4.5 3/16 15.5 5/8 15° 1° 30° 37° 41° 17081721 4.5 3/16 15.5 5 /8 15° 1° 30° 37° 41° 17081725 4.5 3/16 15.5 5 /8 15° 1° 30° 37° 41° 17081726 4.5 3/16 15.5 5/8 15° 1° 30° 37° 41° 17081727 4.5 3/16 15.5 5/8 15° 1° 30° 37° 41° 17081630 38° CARBURETOR 1 cX o 6 C 2 -2 5 3< o 2 MODEL 2SE CD CARBURETOR MODEL M2ME 6C3-1 SECTION 6C3 CARBURETOR MODEL M2ME CONTENTS G eneral D escription......................................................... ..6C3-1 C arb u reto r O peratio n ......................................................6C3-2 On-Vehicle S ervice.......................................................... ..6C3-2 A d ju stm en ts.......................................................................6C3-2 Checking C hoke................................................................6C3-11 Checking Idle S olen o id................................................ ..6C3-11 Idle M ixture A d ju stm e n t...............................................6C3-11 C arburetor M ounting T o rq u e .......................................6C3-11 C arburetor R eplacem ent........ ..................................... ..6C3-11 U nit R e p a ir........................................................................ ..6C3-12 D isassem bly..................................................................... ..6C3-12 C lean in g ..............................................................................6C3-16 A ssem bly......................................................... ...................6C3-17 A djustm ent Specifications..............................................6C3-21 GENERAL DESCRIPTION The M 2M E carburetors (Fig. 6C3-2) for light duty emission vehicles are basically carryover for the 1981 model except a new electric choke carburetor is used replacing the hot air choke model (M 2M C ) previously used. All models include ta m p e r-re sista n t featu res such as rivets, plugs, covers, etc. to discourage readjustm ent of facotory settings which could affect eith er or both em ission control and driveability. For example, as a carryover feature, blind ^ j- & . VAPOR VENTTUBE (TO CANISTER) IDLE SPEED SOLENOID FRONT VACUUM BREAK PLUG (IDLE MIXTURE NEEDLE) Fig. 6C3-1-M odel M2ME rivets are installed at the factory to retain the setting of the therm ostatic coil in the housing. A special cut-out is notched in the choke cover which m ust be aligned with an extended tab on one of the choke retainers which is located in the 2 o’clock position. The other two retainers are of the conventional design (no tab). The choke therm ostatic cover and coil assembly m ust not be removed unless required during major carburetor overhaul, or replacem ent of the cover and coil assembly or choke housing in which case special service procedures are necessary. An integral 2" pleated paper fuel filter, with check valve, is m ounted in the front of the float bowl behind the fuel inlet nut to give m axim um filtration of incoming fuel. The check valve is used to shut off fuel flow to the ca rb u re to r and prevent fuel leaks if a vehicle roll-over should occur. A single pontoon float, brass needle seat, and a rubber tipped float valve with pull clip are used to control fuel level in the float cham ber. The aneroid cavity insert, used on past models, is deleted. This change was m ade to improve fuel handling during vehicle m aneuvers. A plastic filler block is used above the float cham ber to reduce fuel slosh in the float bowl. To reduce the possibility of fuel vapor losses, the following c a rb u re to r changes have been m ade to m eet evaporative emission requirem ents. • Pum p plunger stem seal and retainer added to the air horn on all models. • Raised beads added to the air horn and float bowl gasket m ating surfaces, and air horn gasket, for good air horn to bowl sealing. • The new model M 2M E carburetor uses two (2) addi­ tional air horn to bowl a tta ch in g screws and lockwashers. • Four (4) throttle body to bowl screws used for improved sealing as a carryover feature. • Idle m ixture needle plugs vapor sealed. T he c a rb u re to r has internally balanced venting through a vent tube, pressed into the air horn casting, located adjacent to the air intake, and by a vent slot located directly over the float cham ber. In addition, vent baffles located strategically in the float bowl provide efficient fuel LIGHT TRUCK SERVICE MANUAL 6C3-2 CARBURETOR MODEL M2ME handling during severe vehicle m aneuvers and hot engine operation. All m odels are ex tern ally vented th ro u g h a tube (Location T) in the float bowl. A hose connects this tube directly to a vacuum operated vapor vent valve located in the vapor canister. W hen the engine is not running, the canister vapor vent valve is open allowing fuel vapors from the float cham ber to pass into the canister where they are storeed until norm ally purged. T he venting of fuel vapors from the ca rb u re to r float bowl to th e can ister m eets evaporative emission requirem ents and improves hot engine starting. Adjustable Part Throttle In order to provide a close tolerance adjustm ent in the main m etering system , an adjustm ent is provided to very accurately set the depth of the m etering rods in the main m etering jets. The ad justm ent feature consists of a pin pressed in the side of the power piston which extends through a slot in the side of the piston well. W hen the power piston is down (economy position), the side of the pin stops on top of a flat surface on the ad justm ent screw located in the cavity next to the power piston. T he adjustm ent screw is held from turning by a tension spring beneath the head of the adjustm ent screw. D uring production flow test, this adjustm ent screw is turned up or down which, in turn, raises or lowers the power piston and m etering rod assembly. This very accurately controls the fuel flow between the rods and jets to meet emission requirem ents. N o a tte m p t should be m ade to change the A P T adjustm ent. If float bowl replacem ent is required, the new bowl assem bly will include an adjustm ent screw pre-set by the factory. All models use a bowl m ounted choke housing with a n on -ad ju stab le electrically operated th e rm o sta tic choke control assembly. A single front vacuum break is used for control of choke valve opening after initial engine start. O ther features include an alum inum throttle body for decreased weight and improved heat distribution, plus a thick throttle body to bowl insulator gasket to keep excessive heat from the float bowl. A new special coated throttle body to bowl gasket reduces fuel vapor losses. For ease of service, alp h a b etic al code le tte rs are included on the air horn, float bowl and throttle body casting at external tube locations to identify air and vacuum hose connections. The carburetor part num ber is stam ped vertically on the left rear corner of the float bowl (Fig. 6C3-2). R efer to the part num ber on the bowl when servicing the carburetor. W hen replacing the float bowl assembly, follow the instruc­ tions contained in the service package. Stam p or engrave the model num ber on the new float bowl. As a carryover item , th e idle m ixture needles are recessed in the throttle body casting and sealed with a hardened steel plug to discourage tam pering in the field which could upset exhaust emissions. The plugs m ust not be removed and idle m ixture needles readjusted unless required due to m ajor carburetor overhaul in which case special procedures must be followed carefully. An E xhaust G as R ecirculation System (E .G .R .) is used on Light Duty vehicles to control oxides of nitrogen (N O x). The vacuum ports necessary to operate the recirculation valve are located in the throttle body and connect through a channel to a tube in the throttle body. This tube is connected by a hose to the E.G .R . valve (See Idle System for port location). On models used with air conditioning, an electrically operated A /C idle speed solenoid is used to m aintain proper idle speed when the air conditioning is in operation. Carburetor Operation Incorporated in the Model M 2M C carburetors are six basic systems. They are float, idle, main metering, power, pump, and choke (Figs. 6C3-3 and 4). ON-VEHICLE SERVICE CARBURETOR ADJUSTMENTS Before checking or resetting the carburetor as the cause of poor engine perform ance or rough idle, check ignition system including distributor, timing, spark plugs and wires. C heck air cleaner, evaporative em ission system , E F E system, PCV system, E G R valve and engine compression. Also inspect in tak e m anifold vacuum hose gaskets and connections for leaks and check torques of c arb u reto r m ounting bolts/nuts. Refer to Figures 6C3-A through 6C 3-F for carburetor adjustm ent procedures. CARBURETOR MODEL M2ME .FLOAT HINGE PULL CLIP 6C3-3 INTERNAL VENT TUBE / INTERNAL VENT SLOT / FLOAT NEI FLOAT NEEDLE SEAT VE NTTUBE TO CANISTER INLET FILTER FUEL I CHECK VALVE SEAT FLOAT SYSTEM ‘ EXHAUST GAS RECIRCULATION RICH MIXTURE SCREW (FACTORY ADJUSTED) COVER IDLE AIR BLEED VALVE (FACTORY ADJUSTED) LEAN M IXTURE SCREW (FACTORY ADJUSTED) VALVE STEM IDLE AIR BLEED MAIN M ETERING ROD MAIN METERING JET IDLE MIXTURE IDLE NEEDLE DISCHARGE (FACTORY ADJUSTED) HOLE PLUG THRO TTLE VALVE (DO TTED LINE - OFF IDLE PO SITION ) IDLE SYSTEM IDLE AIR BLEED VALVE (FA C TO R Y A D JU S TE D ) RIC H M IX TU R E SCREW (F A C TO R Y A D JU S TE D ) M AIN W ELL AIR BLEEDS LEAN M IX TU R E SCREW (FA C T O R Y A D JU S TE D ) S O L E N O ID PLU N G ER (SHO'.VN UP) PU LL-OVER E N R IC H M E N T / r M A IN D IS C H A R G E N O ZZLE M A IN VE N TU R I M A IN M E TE R IN G RO DS ( 2 )' M A IN M ETE R IN G JETS (2) T H R O TTLE VALVE MAIN METERING SYSTEM (PART THROTTLE OPERATION) Fig. 6C3-3--Basic Systems LIGHT TRUCK SERVICE MANUAL 6C3-4 CARBURETOR MODEL M2ME R IC H M IX TU R E SCREW (FA C TO R Y A D JU S TE D ) S RIVETED COVER IDLE AIR BLEED VALVE (FA C TO R Y A D JU S TE D ) LEAN M IX TU R E SCREW (FA C TO R Y A D JU S TE D ) SO LE N O ID PLUNG ER (SH O W N U P ). M A IN D IS C H A R G E N O ZZL E M AIN M ETE R IN G RO DS (2) PLUG M AIN M ETE R IN G JETS (2) T H R O TTLE VALVE W ID E-O P EN TH R O TTLE EN R IC H M E N T S W IT C H MAIN METERING SYSTEM (WIDE-OPEN THROTTLE OPERATION) R E T A IN E R SEAL PUMP LE V E R P U M P S U C T IO N BREAKER D IS C H A R G E PASSAGE D IS C H A R G E B A L L R E T A IN E R D IS C H A R G E C H E C K BALL CUP SEAL ! PUM P PLUNG ER PUMP SYSTEM CHOKE CHOKE INSET VA CU UM BREAK W IT H LE AF-TYP E BUCKING SPRING (S E E IN S E T) UNLOADER TANG FAST IDLE ADJUSTING SCREW CHOKE SYSTEM (ELECTRIC CHOKE TYPE) Fig. 6C3-4--Basic Systems LIGHT TRUCK SERVICE MANUAL CARBURETOR MODEL M2ME 6C3-5 FLOAT ADJUSTMENT (M EC H A N IC AL SETTIN G ) G A U G E F R O M T O P O F C A S T I N G TO T O P OF F L O A T — G A U G I N G P O I N T 3 1 6 " B A C K F R O M E N D OF F L O A T A T T O E (SEE IN S E T ) G A U G IN G PO INT (3 1 6 BACK F R O M TO E ) REM OVE FLOAT A N D BEND FLOAT A R M U P OR D O W N TO A D J U S T PUSH FLOAT D O W N LIG H TL Y A G A I N S T NEEDLE V IS U A L L Y CHECK FLOAT A L IG N M E N T AFTER A D J U S T IN G PUMP ADJUSTMENT © GAUGE FROM TO P OF C H O K E V A L V E W A L L , N E X T TO V E N T S T A C K , TO TO P OF P U M P S T E M A S S P E C IF IE D m u 5JB E N D PUMP- LEVER TO ADJUST ^ © ROD IN S P E C IF I E D HOLE OF P U M P L E V E R S U P P O R T LEVER W IT H S C R E W D R IV E R B E N D IN G © W H IL E LEVER THROTTLE VALVES C O M PLETELY CLOSED N O T E : M A K E S U R E F A S T ID L E CAM FO LLOW ER LEVER IS OFF S T E P S O N F A S T ID L E C A M Fig. 6C3-A--Model M2ME Adjustments LIGHT TRUCK SERVICE MANUAL 6C3-6 CARBURETOR MODEL M2ME CHOKE COIL LEVER ADJUSTMENT (SEE NOTE) N O T E : IF A D J U S T M E N T ,s N E C E S S A R Y , D R IL L 0 UT R IV E T S A N D R E M O V E B E N D C H O K E R O D A T T H IS P O IN T T O A D J U S T (SEE IN S E T ) i l ------1 C H O KE VALVE C LO SED n INSET C H O KE C O V ER . USE S TA T C O V E R R E T A IN E R K IT . 3 ) P U S H U P O N T H E R M O S T A T IC C O IL T A N G (C O U N T E R C L O C K W IS E ) U N T IL C H O K E V A L V E IS C L O S E D . LO W E R E D G E O F LE V E R S H O U L D J U S T C O N T A C T S ID E O F P L U G GAUGE. UJ \ 4 ; IN S E R T 1 2 0 ” PLUG G A U G E IF N E C E S S A R Y , D R IL L OUT A N D R EM O V E R IV E T S . R E M O V E T H E T H E R M O S T A T IC C O V E R A N D C O IL A S S E M B L Y F R O M C H O K E H O U S IN G P L A C E F A S T ID L E C A M F O L L O W E R O N H IG H S TE P OF F A S T ID L E C A M . FAST IDLE ADJUSTMENT (BENCH SETTING) NOTE: R E C H E C K FAST ID L E A D JU ST M EN T ON THE V E H IC L E SETT IN G TO SP EC IF IC A T IO N S. H O LD CAM FO LLO W ER ON H IG H EST S T E P ----OF FAST ID L E CA M S TU RN SCREW IN TO C O N T A C T L E V E R THEN T U RN SCREW IN 4 V 2 T U R N S (NOTE) S T U R N FAST ID L E SCREW OUT U N T IL P R IM A R Y T H RO TTLE V A L V E S A R E CLO SED. Fig. 6C3-B--Model M2ME Adjustments LIGHT TRUCK SERVICE MANUAL CARBURETOR MODEL M2ME 6C3-7 FAST IDLE CAM (CHOKE ROD) RELATION ADJUSTMENT FIGURE 1 1. CHOKE COIL LEVER ADJUSTMENT MUST BE CORRECT AND FAST IDLE ADJUSTMENT MUST BE MADE BEFORE PROCEEDING. 2. USE CHOKE VALVE MEASURING GAUGE J-26701. TOOL M AY BE USED WITH CARBURETOR ON OR OFF ENGINE. IF OFF ENGINE. PLACE CARBURETOR ON HOLDING FIXTURE SO THAT IT WILL REMAIN IN SAME POSITION WHEN GAUGE IS IN PLACE. 3. ROTATE DEGREE SCALE UNTIL ZERO (0) IS OPPOSITE POINTER. 4. WITH CHOKE VALVE COMPLETELY CLOSED, PLACE MAGNET SQUARELY ON TOP OF CHOKE VALVE. 5. ROTATE BUBBLE UNTIL IT IS CENTERED. FIGURE 2 6. ROTATE SCALE SO THAT DEGREE SPECIFIED FOR ADJUSTMENT IS OPPOSITE POINTER. 7. PLACE CAM FOLLOWER ON SECOND STEP OF CAM AGAINST RISE OF HIGH STEP. 8. CLOSE CHOKE BY PUSHING UPWARD ON CHOKE COIL LEVER OR VACUUM BREAK LEVER TANG (HOLD IN POSITION WITH RUBBER BAND). 9. 10. TO ADJUST, BEND TANG ON FAST IDLE CAM UNTIL BUBBLE IS CENTERED. REMOVE GAUGE. LEVELING BUBBLE (CENTERED) Sl/C HO KE VALVE CLOSED © M A K E CHOKE COIL LEVER AND FAST IDLE ADJUSTMENT (BENCH OR ON-THE-CAR SETTING). SPECIFIED ANGLE (SEE SPECS.) ® TO ADJUST, BEND TANG ON FAST IDLE CAM UNTIL BUBBLE IS CENTERED. © CLOSE CHOKE BY PUSHING UPWARD ON CHOKE COIL LEVER OR VACUUM BREAK LEVER TANG (HOLD IN POSITION WITH RUBBER BAND). FAST IDLE CAM PLACE CAM FOLLOWER ON SECOND STEP OF CAM AGAINST RISE OF HIGH STEP. REMOVE GAUGE. N O TE : MAKE C H O K E C O IL LEVER AND FAST IDLE A D JU S T M E N T (B E N C H OR O N -TH E -C A R S E TTIN G ). DO N O T R EM O VE RIVETS A ND C H O K E COVER TO PERFO RM TH IS A D JU S TM E N T. USE RUBBER BAND ON V A C U U M BREAK LEVER TA N G TO HOLD CHOKE VALVE C LO SE D (STEP 8 ). Fig. 6C3-C--Model M2ME Adjustments LIGHT TRUCK SERVICE MANUAL 6C3-8 CARBURETOR MODEL M2ME FRONT VACUUM BREAK ADJUSTMENT ANGLE GAUGE METHOD FIGURE 1 1. USE CHOKE VALVE M EASU RIN G GAUGE J-26701 . TOOL M AY BE USED WITH CARBURETOR ON OR OFF ENGINE. IF OFF ENGINE, PLACE CARBURETOR ON HOLDING FIXTURE SO THAT IT WILL REM AIN IN S A M E POSITION WHEN GAUGE IS IN PLACE. 2. ROTATE DEGREE SCALE UNTIL ZERO (0) IS OPPOSITE POINTER. 3. PLACE M AGNET SQUARELY ON TOP OF CHOKE VALVE. 4. CHOKE VALVE COMPLETELY CLOSED. 5. ROTATE BUBBLE UNTIL IT IS CENTERED. FIGURE 2 6. ROTATE SCALE SO THAT DEGREE SPECIFIED FOR ADJUST MENT IS OPPOSITE POINTER. 7. SEAT CHOKE VACUUM DIAPHRAGM USING VACUU M SOURCE. 8. HOLD CHO KE VALVE TOWARD CLO SED POSITION, PUSH IN G UPW ARD ON CHOKE COIL LEVER OR VACUUM BREAK LEVER TANG (HOLD IN POSITION WITH RUBBER BAND). 9. TO ADJUST, TURN SCREW IN OR OUT UNTIL BUBBLE IS CENTERED. 10. REMOVE GAUGE. SPECIFIED ANGLE (SEE SPECS.) ©DEGREE>, SCALE © P O IN T E R NOTE 2: LEAF BUCKING SPRING MUST BE SEATED AGAINST LEVER (WHERE USED) RUBBER BAND LEVELING BUBBLE (CENTERED) , ©CHOKE VALVE CLOSED Y\ M A G N ET O j/-'\ } TURN SCREW TO ADJUST UNTIL BUBBLE FIGURE 1 IS CENTERED S SEAT DIAPHRAGM ? ( M W LIGHTLY CLOSE CHOKE FIGURE BY PUSHING UPWARD ON CHOKE COIL LEVER OR VACUUM BREAK LEVER TANG (HOLD IN POSITION WITH RUBBER BAND). J z ) USING VACUUM SO U RCE N0TE:T H R O T T L E V A L V E S CO M PLETELY CLOSED NO TE M A K E S U R E F A S T ID LE C A M F O L L O W E R L E V E R IS OFF S T E P S O N F A S T ID L E C A M B E N D S E C O N D A R Y C L O S IN G T A N G A W A Y T O C L O S E P R IM A R Y V A L V E S , T H E N RE A D J U S T Fig. 6C4-A--M4M Adjustments-1 of 9 LIGHT TRU CK SERVICE MANUAL CARBURETOR MODEL M 4M 6C4-7 CHOKE COIL LEVER ADJUSTMENT (SEE N O TE ) BEND C H O K E R O D A T T H IS P O IN T TO A D JU S T (SEE IN S E T) 11 I C H O K E VALVE C LO SED NO TE: IF A D JU S T M E N T IS N E C E S S A R Y , DRILL O UT R IV E TS AND REM O VE C H O K E CO VER . USE S T A T CO VER RETAINER KIT. ■\ PUSH UP ON T H E R M O S T A T IC C O IL T A N G (C O U N T E R C L O C K W IS E ) U N T IL C H O K E VALVE IS CLOSED. W LOW ER ED G E OF LEVER S H O U L D JU ST C O N T A C T S ID E OF PLUG G A U G E. 43 IN S E R T .1 2 0 PLUG G AUG E. IF N E C E S S A R Y , DRILL OUT A N D REMOVE R IV E T S . REM O VE TH E T H E R M O S T A T IC CO VER A N D C O IL ASSEM BLY FRO M C H O K E H O U S IN G . © P L A C E FAST IDLE CAM FO LLO W ER O N H IG H STEP O F FAST IDLE CA M . FAST IDLE ADJUSTMENT (BENCH SETTING) N O T E : R E C H E C K FA ST ID L E A D J U S T M E N T O N T H E V E H IC L E S E T T IN G T O S P E C IF IC A T IO N S . cx ( 7 ) H O LD CAM FOLLOW ER ON H IG H E S T STEP O F FAST ID L E C A M 0 T U R N SCREW IN T O CO NTACT LEVER THEN T U R N SC R EW IN S P E C IF IE D N U M B E R O F T U R N S (N O T E ) T U R N F A S T ID L E SCREW O U T U N T IL P R IM A R Y T H R O T TL E V A L V E S ARE CLOSED. Fig. 6C4-B--M4M Adjustments - 2 of 9 LIGHT TRUCK SERVICE MANUAL 6C4-8 CARBURETOR MODEL M 4M FAST IDLE CAM (CHOKE ROD) RELATION ADJUSTMENT FIGURE 1 1. CHOKE COIL LEVER ADJUSTMENT MUST BE CORRECT AND FAST IDLE ADJUSTMENT MUST BE MADE BEFORE PROCEEDING. 2. USE CHOKE VALVE MEASURING GAUGE J-26701 . TOOL MAY BE USED WITH CARBURETOR ON OR OFF ENGINE. IF OFF ENGINE, PLACE CARBURETOR ON HOLDING FIXTURE SO THAT IT WILL REMAIN IN SAME POSITION WHEN GAUGE IS IN PLACE. ROTATE DEGREE SCALE UNTIL ZERO (0) IS OPPOSITE POINTER. 3. 4. WITH CHOKE VALVE COMPLETELY CLOSED, PLACE MAGNET SQUARELY ON TOP OF CHOKE VALVE. 5. ROTATE BUBBLE UNTIL IT IS CENTERED. 6. FIGURE 2 ROTATE SCALE SO THAT DEGREE SPECIFIED FOR ADJUSTMENT IS OPPOSITE POINTER. 7. PLACE CAM FOLLOWER ON SECOND STEP OF CAM AGAINST RISE OF HIGH STEP. 8. CLOSE CHOKE BY PUSHING UPWARD ON CHOKE COIL LEVER OR VACUUM BREAK LEVER TANG (HOLD IN POSITION WITH RUBBER BAND). 9. 10. TO ADJUST, BEND TANG ON FAST IDLE CAM UNTIL BUBBLE IS CENTERED. REMOVE GAUGE. © M A K E CHOKE COIL LEVER AND FAST IDLE ADJUSTMENT (BENCH OR ON-THECAR SETTING). NOTE: DO NOT REMOVE RIVETS AND CHOKE COVER TO PERFORM THIS ADJUSTMENT. USE RUBBER BAND ON VACUUM BREAK LEVER TANG TO HOLD CHOKE VALVE CLOSED, (STEP 8). { § ) SPECIFIED ANGLE (SEE SPECS.) ( D TO ADJUST, BEND TANG ON FAST IDLE CAM RUBBER UNTIL BUBBLE IS BAND CENTERED. FAST IDLE CAM LIGHTLY CLOSE CHOKE BY PUSHING UPWARD ON CHOKE COIL LEVER OR VACUUM BREAK LEVER TANG (HOLD IN POSITION WITH RUBBER BAND). REMOVE GAUGE. FIGURE 2 PLACE CAM FOLLOWER ON SECOND STEP OF CAM AGAINST RISE OF HIGH STEP. AIR VALVE ROD ADJUSTMENT - FRONT ® © PLACE .015 GAUGE BETWEEN ROD AND END OF SLOT IN LEVER SEAT CHOKE VACUUM AIR VALVE DIAPHRAGM USING COMPLETELY OUTSIDE VACUUM SOURCE © BEND HERE FOR SPECIFIED CLEARANCE BETWEEN ROD AND END OF SLOT IN LEVER Fig. 6C4-C--M4M Adjustments-3 of 9 LIGHT TRUCK SERVICE MANUAL CARBURETOR MODEL M 4M 6C4-9 AIR VALVE ROD ADJUSTMENT - REAR (LIGHT DUTY TRUCK ONLY — NON-CALIFORNIA APPLICATIONS) AIR VALVE COMPLETELY CLOSED © PLACE GAUGE BETWEEN ROD AND END OF SLOT IN LEVER BEND ROD FOR SPECIFIED CLEARANCE BETWEEN ROD AND END OF SLOT IN LEVER SEAT CHOKE VACUUM DIAPHRAGM USING OUTSIDE VACUUM SOURCE FRONT VACUUM BREAK ADJUSTMENT ANGLE GAUGE METHOD FIG U RE 1 USE C H O K E VA LVE M E A S U R IN G G AUG E J 26701 . TO OL M A Y BE USED W IT H C A R B U R ETO R O N OR OFF EN G INE. IF OFF EN G IN E . PLACE C A R B U R ETO R O N H O LD IN G FIXTU RE SO T H A T IT W ILL R E M A IN IN S A M E P O S ITIO N W H E N G A U G E IS IN PLACE. 1. 2. ROTATE DEGREE SCALE UNTIL ZERO (OHS OPPOSITE POINTER. 3. PLACE M A G N E T S Q U A R E LY O N TO P OF CHOKE VALVE. 4. CH OK E VA LV E CO M PLETELY CLOSED. 5. RO TA TE BUBBLE UN TIL IT IS CENTERED. FIGURE 2 6. ROTATE SCALE SO T H A T DEGREE SPECIFIED FOR A D JU S T M E N T IS O PPO SITE POINTER. 7. SEAT CHOKE VACUUM DIAPHRAGM USING VACUUM SOURCE. 8. H O L D C H O K E VA LVE T O W A R D C L O S E D P O S IT IO N , P U S H IN G U P W A R D O N C H O K E C O IL LEVER OR V A C U U M B R EA K LEVER T A N G (H O L D IN P O S IT IO N W IT H R U B B ER B A N D ). 9. 10. TO A D JU S T , T U R N SCREW IN OR O U T U N TIL BUBBLE IS CENTERED. RE M O VE G AUGE. LEVELING BUBBLE (CENTERED) CHOKE % , VA LVE CLOSED N O T E 2: LEAF B U C K IN G S P R IN G M U S T BE SE A TE D A G A IN S T ; LEVER _____ _ (W H ER E U S E D ) » ^ ' BA ND - S E A T D IA P H R A G M \ / \ /} U S IN G V A C U U M S O U R C E / /X J ? N O T E : O N D E LA Y M O D E L S W IT H AIR c /A m o, r e m o v e R U BB ER C O V E R O VER E L E M E N T A N D P LU G SM A LL BLEED HO LE IN V A C U U M T U B E W IT H TA PE. R E M O VE TA PE A FTER A D J U S T ­ M ENT. L IG H T L Y C L O S E C H O K E BY P U S H IN G UP W A R D O N C H O K E C O IL LEVER OR V A C U U M BREAK LEVER T A N G (H O L D IN P O S IT IO N W IT H R U BB ER B A N D ). REMOVE V A C U U M BREAK FROM C A RB UR­ ETOR. PLACE BRACKET IN A VISE AN D . USING SAFETY PR ECAUTIO NS, G RIND OFF W ELD HOLDING A D JU S T M E N T SCREW COVER. REMOVE COVER A N D REINSTALL V A C U U M BREAK. N O TE 1: MAKE CHOKE COIL LEVER A N D FAST IDLE A D JU S TM E N T (BENCH OR ON-THE-CAR SETTING). D £ NOT REMOVE RIVETS A N D CHOKE COVER TO PERFORM TH IS A D JU S TM E N T . USE RUBBER BA ND ON VA C U U M BREAK LEVER TANG TO HOLD CHOKE VALVE CLOSED (STEP 8). Fig. 6C 4-D-M 4M Adjustments - 4 of 9 LIGHT TRUCK SERVICE MANUAL 6C4-10 CARBURETOR MODEL M4M REAR VACUUM BREAK ADJUSTMENT - TYPICAL (SCREW ADJUSTMENT TYPE) 1. USE CHOKE VALVE MEASURING GAUGE J-26701. TOOL MAY BE USED WITH CARBURETOR ON OR OFF ENGINE. IF OFF ENGINE, PLACE CARBURETOR ON HOLDING FIXTURE SO THAT IT WILL REMAIN IN SAME POSITION WHEN GAUGE IS IN PLACE. FIGURE 1 2. CHOKE COIL LEVER ADJUSTMENT MUST BE CORRECT AND FAST IDLE ADJUSTMENT MUST BE MADE BEFORE PROCEEDING. 3. ROTATE DEGREE SCALE UNTIL ZERO (0) IS OPPOSITE POINTER. 4. WITH CHOKE VALVE COMPLETELY CLOSED, PLACE MAGNET SQUARELY ON TOP OF CHOKE VALVE. 5. ROTATE BUBBLE UNTIL IT IS CENTERED. FIGURE 2 6. ROTATE SCALE SO THAT DEGREE SPECIFIED FOR ADJUST MENT IS OPPOSITE POINTER. 7. SEAT CHOKE VACUUM DIAPHRAGM USING VACUUM SOURCE. 8. HOLD CHOKE VALVE TOWARD CLOSED POSITION, PUSHING UPWARD ON CHOKE COIL LEVER OR VACUUM BREAK LEVER TANG (HOLD IN POSITION WITH RUBBER BAND). 9. TO ADJUST, USING 1/8” HEX WRENCH TURN SCREW IN REAR COVER UNTIL BUBBLE IS CENTERED. APPLY SEALER (SUCH AS SILICONE SEALANT RTV RUBBER OR EQUIVALENT) OVER SCREW HEAD TO SEAL SETTING. 10. REMOVE GAUGE. © REMOVE V A C U U M BREAK FROM CARBURETOR. PLACE BRACKET IN A VISE A N D , USING SAFETY PRECAUTIONS, GRIND OFF A D J U S T M E N T SCREW CAP. RE­ IN STA LL VA C U U M BREAK. SPECIFIED ANGLE (SEE SPECS.) _ L TO ADJUST, USING 1 /8 ” HEX W RENCH TURN SCREW IN REAR COVER UNTIL BUBBLE IS CENTERED. APPLY SEALER (SU C H AS SILIQONE SEA LAN T RTV RUBBER OR EQ UIVALENT) OVER SCREW HEAD TO SEAL S E TT IN G . LEVELING BUBBLE (C E N TFR E D ) RUBBER BAND FIG U R E 3 PLUNGER BUCKING SPRING ® SEAT DIAPHRAGM USIN G VAC UUM SOURCE (S E E NOTE 2) LIGHTLY CLOSE CHOKE BY PUS H IN G UPWARD ON CHOKE CO IL LEVER OR VACUUM BREAK LEVER TA N G (HO LD IN PO S ITIO N W ITH RUBBER BAND). MAKE SURE PLUNGER BUCKING SPRING (IF USED) IS COMPRESSED A ND S E A T E D . NOTE 2: ON DELAY M O DELS, PLUG END COVER USING AN ACCELERATOR PUMP PLUNG ER CUP • 2G TYPE (FIG U R E 3 ) OR EQUIVALENT. SE A T VACUUM DIAPHRAGM M AKING SURE VAC UUM IS ABOVE 5 " Hg WHEN READING GAUGE (STEP 9 ). REMOVE CUP AFTER A D JUSTM ENT. NOTE 1: MAKE CHOKE COIL LEVER A D JU S TM EN T A N D FAST IDLE A D JU S TM E N T. DO NOT REMOVE RIVETS A N D CHOKE COVER TO PERFORM THIS A D JU S TM E N T . USE RUBBER BAND ON V A C U U M BREAK LEVER TANG TO HOLD CHOKE VALVE CLOSED (STEP 8). Fig. 6C4-E--M4M Adjustments-5 of 9 LIGHT TRU CK SERVICE MANUAL CARBURETOR MODEL M 4M 6C 4-11 UNLOADER ADJUSTMENT - TYPICAL 1. USE CHOKE VALVE M EA SU R IN G GAUGE J-26701. TOOL M A Y BE USED WITH CARBURETOR ON OR OFF ENGINE. IF OFF ENGINE, PLACE CARBURETOR ON HOLDING FIXTURE SO THAT IT WILL REM A IN IN S A M E POSITION WHEN GAUGE IS IN PLACE. FIGURE 1 2. CHOKE COIL LEVER ADJUSTMENT MUST BE CORRECT AND FAST IDLE ADJUSTMENT MUST BE MADE BEFORE PROCEEDING. 3. ROTATE DEGREE SCALE UNTIL ZERO (0) IS OPPOSITE POINTER. 4. WITH CHOKE VALVE COMPLETELY CLOSED. PLACE M A G N ET SQUARELY ON TOP OF CHOKE VALVE. 5. ROTATE BUBBLE UNTIL IT IS CENTERED. FIGURE 2 6. ROTATE SCALE SO THAT DEGREE SPECIFIED FOR ADJUST MENT IS OPPOSITE POINTER. 7. IF REMOVED, INSTALL CHOKE THERMOSTATIC COVER AND COIL ASSEMBLY IN HOUSING. 8. CLOSE CHOKE VALVE BY PUSHING UP ON TANG ON V A C U U M BREAK LEVER (HOLD IN POSITION WITH RUBBER BAND). 9. HOLD P R IM A R Y THROTTLE VALVES W IDE OPEN. 10. TO ADJUST, BEND TANG ON FAST IDLE LEVER UNTIL BUBBLE IS CENTERED. 11. REMOVE GAUGE. © MAKE CHOKE COIL LEVER AND FAST IDLE ADJUSTMENT (BENCH OR ON-THE-CAR SETTING). NOTE: DO NOT REMOVE RIVETS AND CHOKE COVER TO PERFORM THIS ADJUSTMENT. USE RUBBER BAND ON VACUUM BREAK LEVER TANG TO HOLD CHOKE VALVE CLOSED (STEP 8). 6) SPECIFIED HOLD PRIM ARY ANGLE (SEE SPECS.) THROTTLE VALVES LEVELING W ,DE0PEN BUBBLE (CENTERED) VACUUM BREAK \ LEVER TANG CHOKE RUBBER VALVE BAND CLOSED FIGURE 1 IF REMOVED, INSTALL CHOKE © THERMOSTATIC COVER AND COIL ASSEMBLY IN HOUSING. BEND TANG TO A D JU ST UNTIL BUBBLE IS CENTERED. CLOSE CHOKE VALVE BY PUSHING UP ON TANG ON VACUUM BREAK LEVER (HOLD IN POSITION WITH RUBBER BAND). Fig. 6C4-F--M4M Adjustments - 6 of 9 LIGHT TRUCK SERVICE MANUAL 6C 4-12 CARBURETOR MODEL M 4M SECONDARY LOCKOUT ADJUSTMENT CHOKE VA L V E PUSH DOWN ON T A IL OF CAM (STEP 2) H O L D C H O K E V A L V E W ID E O P E N BY P U S H IN G D O W N O N CHOKE VALVE CLOSED THROTTLE VALVES CLOSED B E N D P IN TO A D J U S T x ^ 5 ' x ----- --015 MAX CLEARANCE T A IL OF F A S T ID L E C A M C H E C K L O C K O U T P IN FO R C L E A R A N C E FILE E N D OF P IN (C H E C K FO R N O B U R R S AFTER F IL IN G ) S E C O N D A R Y L O C K O U T LEVER © S ID E C L E A R A N C E ^GAUGE FOR C L E A R A N C E SECO ND ARY LO CKOUT ©2 ) O P E N IN G C L E A R A N C E SECONDARY CLOSING ADJUSTMENT ( T ) L E V E R AG AINST TANG ( T ) E N G I N E ID L E ^ " " s E T TO PROPER ID L E R.P.M. (7)c HOKE V A L V E ^ ^ “^ W ID E OPEN CAM FOLLOW ER O F F STEPS O F FAST ID L E CAM ( j H B E N D TANG ^ T O ADJUST (7 ) .020" ^ -" C L E A R A N C E SECONDARY OPENING ADJUSTMENT Fig. 6C4-G--M4M Adjustments - 7 of 9 LIGHT TRU CK SERVICE MANUAL CARBURETOR MODEL M4M 6C 4-13 CARBURETOR ADJUSTMENTS AIR VALVE SPRING ADJUSTMENT C 3*J) T' U R N TENSIO N ADJUSTING SCREW CLOCKWISE U N T IL A IR V A L V E JUST CLOSES. THEN T U R N ADJUSTING SCREW CLOCKWISE SPECIFIED NUM BER O F TURNS T IG H T E N LOCK SCREW (LOOSEN LOCK SCREW USING SPECIAL HEX WRENCH 2 J T U R N TENSIO N ADJUSTING V " S C R E W COUNTERCLOCKWISE U N T IL A IR V A L V E OPENS PART WAY IDLE SPEED ADJUSTMENT - WITHOUT SOLENOID ® PREPARE V E H I C L E FOR A D J U S T M E N T S SEE EMISSION L A B E L ON V E H IC L E . N OTE : I G N I T I O N T I M I N G SET PER L A B E L . 1T U R N ID L E SPEED SCREW TO SET C UR B I D L E SPEED TO S P E C IF IC A T IO N S - A / C OF F (SEE EMISSION L A B E L ) A/C IDLE SPEED ADJUSTMENT - WITH SOLENOID SOLENOID ENERGIZED A /C COMPRESSOR LEAD DISCONNECTED AT A/C COMPRESSOR, A /C O N , A /TTR A N S M IS SIO N IN . DRIVE, M /T IN NEUTRAL © PREPARE VEHICLE FOR ADJUSTMENTS SEE EMISSION LABEL ON VEHICLE. NOTE: IGNITION TIM ING SET PER LABEL. J” TURN SOLENOID SCREW TO ADJUST TO SPECIFIED RPM. (RECONNECT A/C COMPRESSOR LEAD AFTER ADJUSTMENT) 'OPEN THROTTLE SLIGHTLY TO ALLOW SOLENOID PLUNGER TO FULLY EXTEND \( 3 TURN IDLE SPEED SCREW TO SET CURB IDLE SPEED TO SPECIFICATIONS - A/C OFF (SEE EMISSION LABEL) Fig. 6C4-H--M4M Adjustments 8 of 9 LIGHT TRUCK SERVICE MANUL 6C4-14 CARBURETOR MODEL M4M THROTTLE LEVER ACTUATOR ADJUSTMENT (ON VEHICLE) NOTE: ENGINE MUST BE W ARM CHOKE WIDE OPEN - CA M FOLLOWER OFF STEPS OF FAST IDLE CAM. ©TWITH PLUNGER HELD INWARD. l’RN PLUNGER SCREW IN OR OUT TO OBTAIN SPECIFIED R.P.M. ADJUST IDLE SPEED SCREW TO OBTAIN SPECIFIED CURB IDLE R.P.M. (SEE LABEL). MANUALLY OPEN THROTTLE SLIGHTLY AND ALLOW TO CLOSE AGAINST EXTENDED PLUNGER. I WITH ENGINE SET AT SPECIFIED IDLE SPEED, USING OUTSIDE VACUUM SOURCE APPLY SUFFICIENT VACUUM TO THE ACTUATOR TO EXTEND THE PLUNGER FULLY. FAST IDLE ADJUSTMENT (ON VEHICLE) © P O SITIO N T R A N S M IS S IO N IN P A R K OR N EU TRAL I T y- ® 09 HOLD C A M FOLLOWER ON P RO P ER STEP OF FAST IDLE C A M PER E M IS S IO N LABEL S____t ® D IS C O N N E C T A N D PLUG V A C U U M H O SE AT EGR VALV E TU RN FAST IDLE SC R E W TO O B T A IN SP EC IF IED R P M ON E M IS S IO N LABEL Fig. 6C4-I--M4M Adjustments 9 of 9 UGH TRUCK SERVICE MANUAL ENGINE RUNNING AT IDLE, © WITH CHOKE WIDE-OPEN, CAREFULLY READING AT EYE LEVEL, OBSERVE © MARK ON GAUGE THAT LINES UP o n WITH TOP OF CASTING AT THE VENT SLOT OR VENT HOLE. SETTING SHOULD BE WITHIN ±1/16" FROM SPECIFIED FLOAT LEVEL SETTING. INSERT GAUGE IN VENT SLOT OR VENT HOLE (NEXT TO AIR CLEANER MOUNTING STUD) IN AIR HORN. RELEASE GAUGE AND ALLOW IT TO FLOAT FREELY. CAUTION: DO NOT PRESS DOWN ON GAUGE TO CAUSE FLOODING OR DAMAGE TO FLOAT. REMOVE FLOAT GAUGE FROM AIR HORN. n © IF THE MECHANICAL SETTING (STEP 2) VARIES OVER ±1/16" FROM SPECIFICATIONS, REMOVE AIR HORN AND ADJUST FLOAT LEVEL TO SPECIFICATIONS FOLLOWING NORMAL ADJUST­ MENT PROCEDURES. LIGHT TRUCK SERVICE M AN U AL FLOAT GAUGE — EXTERNAL CHECKING PROCEDURE (DUALJET AND QUADRAJET - TYPICAL) 6C4-16 CARBURETOR MODEL M4M IDLE MIXTURE CHECK AND ADJUSTMENT (PROPANE ENRICHMENT) Light Duty Emission Vehicles Only Idle m ixture screws have been preset at the factory and sealed. Idle m ixture should be adjusted only in the case of major carburetor overhaul, throttle body replacem ent or high emissions as determ ined by offical inspections. A djust­ ing m ixture by other than the following method may violate Federal an d /o r California or other state or Provincial laws. Because of the sealed idle m ixture screws, the idle m ixture checking procedure requires artificial enrichm ent by adding propane. 1. Set parking brake and block drive wheels. On cars equipped with vacuum parking brake release, discon­ nect and plug hose at brake. Engine m ust be at normal operating tem perature and air conditioning off. 2. Disconnect and plug hoses as directed on the Emission Control Inform ation Label under the hood. 3. Connect an accurate tachom eter to engine. 4. Disconnect vacuum advance and set tim ing to specifi­ cation shown on the Emission Control Inform ation Label. Re-connect vacuum advance. 5. Set carburetor idle speed to specification as shown on Emission Control Inform ation Label. 6. Disconnect crankcase ventilation tube from air cleaner. 7. Using tool J-2691 1, insert hose with rubber stopper, from propane valve into crankcase ventilation tube opening in air cleaner. Propane c a rtrid g e m ust be vertical. 11. Lightly seat screws, then back out equally, just enough so engine will run. 12. Place transmission in Drive (autom atics) or N eutral (m anuals). 13. Back each screw out (richen 1/8 turn a t a time until m axim um idle speed is obtained). Then set idle speed to the enriched idle specification. 14. T urn each m ixture screw in (clockwise) 1/8 turn at a tim e until idle speed reaches value given on Emission Control Inform ation Label. 15. Re-check enriched speed with propane. If not within specification, repeat adjustm ent beginning with Step 12 . 16. Check and adjust fast idle as described on Emission Control Inform ation Label. 17. Turn off engine. Remove propane tool, connect crank­ case ventilation tube. Re-connect vacuum hoses. IDLE MIXTURE ADJUSTMENT - BEST IDLE METHOD (For Heavy Duty Emission Vehicles With 4-Barrel) Perform this ad ju stm en t w ith engine at o perating tem perature, parking brake applied and transmission in park or neutral. 1. Remove air cleaner. 2. Connect tachom eter and vacuum gage to engine. 3. As a prelim inary adjustm ent, turn idle m ixture screws in lightly to seat and back out 2 turns. 8. W ith engine idling in drive (neutral for m anual shifts) slowly open propane control valve while pressing button. Continue to add propane until speed drops due to over richness. N ote m axim um engine speed (en­ riched speed). If rich speed drop cannot be obtained check for empty cartridge or propane system leaks. 4. W ith engine running (choke wide open and transm is­ sion in neutral) adjust idle speed screw to idle speed specified on Engine Em ission C ontrol Inform ation Label. 9. If the enriched idle speed is within the enriched idle specification the m ixture is correct. Go to step 17. 6. R epeat steps 4 and 5 until "b e st" idle is obtained. 10. If the enriched idle speed is not within specifications, remove m ixture screw plugs following procedures. LIGHT TRUCK SERVICE MANUAL NOTICE: Do not turn idle m ixture screw tightly against seat or dam age may result. 5. A djust idle m ixture screw to obtain highest R PM . 7. Shut down the engine, remove gages and install air cleaner. CARBURETOR MODEL M 4M 6C 4-17 CARBURETOR REPLACEMENT Removal (Fig. 6C4-7) Flooding, stum ble on acceleration and other perform ­ ance complaints are in many instances, caused by presence of dirt, w ater, or other foreign m atter in carburetor. To aid in diagnosis, carburetor should be carefully removed from engine w ithout draining fuel from bowl. Contents of fuel bowl may then be exam ined for contam ination as carburetor is disassembled. Check filter. 1. Remove air cleaner and gasket. 2. Disconnect wire at solenoid, if equipped. 3. Disconnect fuel pipe and vacuum lines. 4. Disconnect choke system. 5. Disconnect accelerator linkage. 6. If equipped with autom atic transm ission, disconnect downshift cable. 7. If equipped with cruise control, disconnect linkage. 8. Remove c a rb u re to r atta c h in g bolt, c a rb u re to r and insulator. Installation CARBURETOR MOUNTING TORQUE W hen torquing c a rb u re to r a fte r rem oval overhaul, replacem ent or when installing a new heat insulator, torque m ounting bolts, in a clockwise direction, to 16 N-m (144 in. lbs.). W hen retorquing carburetor a t recom m ended m ainte­ nance intervals, check in clockwise direction. If less than 7 N-m (60 in. lbs.), retorque to 11 N-m (96 in. lbs.); if greater than 7 N-m (60 in. lbs.), do not retorque. 1. C lean sealing surfaces on intake m anifold and carburetor. 2. Fill carburetor bowl before installing carburetor. 3. Install carburetor with new insulator and tighten bolts to correct torque (See C arburetor M ounting Torque). 4. Connect downshift cable as required. 5. Connect cruise control cable as required. 6. Connect accelerator linkage. 7. Connect choke system. 8. Connect fuel pipe and vacuum hoses. 9. Connect solenoid as required. 10. Install air cleaner. 11. Check and adjust idle speed. UNIT REPAIR DISASSEMBLY Place c a rb u re to r on a holding fixture to prevent dam age to throttle plates. Solenoid (If Equipped) Remove screws securing the solenoid and bracket to float bowl and remove solenoid and bracket assembly. The solenoid should not be im m ersed in any type of carburetor cleaner and should always be removed before com plete carburetor overhaul. Air Horn 1. Remove upper choke lever from the end of choke shaft by removing retaining screw (Fig. 6C4-8). Then rotate upper choke lever to remove choke rod from slot in lever. 2. Remove choke rod from lower lever inside the float bowl casting by holding lower lever outw ard with small screwdriver and twisting rod counterclockwise. Fig. 6C4-8--Removing Upper Choke Lever LIGHT TRUCK SERVICE MANUAL 6C4-18 CARBURETOR MODEL M 4M 3. Rem ove secondary m etering rods by rem oving the small screw in the top of the m etering rod hanger. Lift upw ard on m etering rod hanger until the secondary m etering rods are com pletely out of the air horn. M etering rods m ay be disassem bled from the hanger by rotating ends out of the holes in the end of the hanger. (Fig. 6C4-9). C O U N TE R S U N K SCREWS (2) (BELOW CHOKE VALVE) 4. Using special tool J-25322, drive small roll pin (pum p lever pivot pin) inw ard ju st enough until pum p lever can be removed from air horn. Then remove pum p lever from pum p rod (Fig. 6C4-10). 5. Remove front vacuum break hose from tube on float bowl. 6. Remove eleven(l 1) air horns to bowl attaching screws; then remove the two counter-sunk screws located next to the venturi (Fig. 6C4-11). Remove secondary air baffle deflector from under the two center air horn screws. SHORT SHORT LO NG LO NG Fig. 6C4-11—Air Horn Screws Remove air horn from float bowl by lifting straight up. The air horn gasket should rem ain on the float bowl for removal later (Fig. 6C4-12). W hen removing air horn from float bowl, use care to prevent bending the small tubes protruding from the air horn. These tubes are perm anently pressed into the air horn casting. DO N O T R E M O V E . Air Horn Disassembly 1. Remove front vacuum break bracket attaching screws (Fig. 6C4-13). The vacuum break diaphragm assembly may now be removed from the air valve dashpot rod Fig. 6C4-9--Removing Secondary Metering Rods Fig. 6C4-10--Removing Pump Lever LIGHT TRUCK SERVICE MANUAL Fig. 6C4-12--Removing Air Horn CARBURETOR MODEL M 4M and the dashpot rod from the air valve lever. Do not place vacuum break assembly in carburetor cleaner. 2. If used, remove pum p plunger stem seal by inverting air horn and using a small screwdriverto remove staking holding the seal re ta in e r in place (Fig. 6C 4-14). Remove and discard retainer and seal. F urth er disassembly of the air horn is not required for cleaning purposes. If part replacem ent is required, proceed as follows: T he air valves and air valve sh aft should not be removed. If it is necessary to replace the air valve closing spring or center plastic eccen tric cam , a rep air kit is available. Instructions for assem bly are included in the repair kit. 6C 4-19 Float Bowl 1. Remove air horn gasket by lifting out of dowel locating pins and lifting tab of gasket from beneath the power piston hanger, being careful not to disto rt springs holding the main m etering rods (Fig. 6C4-15). 2. Remove pum p plunger, and pump plunger stem seal (Fig. 6 C 4 -14) if used, from pump well. 3. Remove pum p return spring from pump well. 4. Remove power piston and m etering rods by depressing piston stem and allowing it to snap free (Fig. 6C4-16). The power piston can be easily removed by pressing the piston down and releasing it with a snap. This will cause the power piston spring to snap the piston up against the retainer. This procedure may have to be repeated several times. Do not remove power piston by using pliers on m etering rod hanger. Remove the power piston spring from the well. The A.P.T. m etering rod adjustm ent screw is pre-set at the factory and no attem pt should be m ade to change this adjustm ent in the field. If float bowl replacem ent is required during service, the new bowl assem bly will be supplied with an A .P.T. m etering rod screw which will be pre-set as required. 5. Remove m etering rods from power piston by discon­ necting tension spring from top of each rod, then rotate rod to remove from hanger. Use care when disassem bling rods to prevent distortion of tension spring an d /o r m etering rods. N ote carefully position of tension spring for later reassembly. 6. Remove plastic filler block over float valve. Fig. 6C4-13--Removing Front Vacuum Break-Typical 7. Remove float assembly and float needle by pulling up on retaining pin. Remove float needle seat and gasket. (Fig. 6C4-17). 8. If used, remove aneroid cavity insert from float bowl (Fig. 6C4-18). 9. Remove prim ary main m etering jets (only if necessary) (Fig. 6C4-19). FLO AT BOWL Fig. 6C4-14--Pump Plunger Stem Seal Fig. 6C4-15--Float Bowl LIGHT TRUCK SERVICE MANUAL 6C4-20 CARBURETOR MODEL M 4M RETAINING SPRING METERING ROD POWER PISTON POWER PISTON SPRING A N E R O ID C A VITY INSERT Fig. 6C4-18--R em oving A neroid Cavity Insert Fig. 6 C 4-16--P o w er Piston and M etering Rods PUMP DISCHARGE CHECK BALL RETAINER AND CHECK BALL NEEDLE SEAT ■ R E M O V IN G TO O L Fig. 6 C 4 -1 9 --F lo a t Bowl Jets Fig. 6C 4-17--R em oving N eedle Seat-Typical NOTICE: N o attempt should be made to remove the secondary metering jet (metering orifice plates). These jets are fixed and, if damaged, bowl replacement is required. 10. Remove pump discharge check ball retainer and check ball. 11. Remove secondary air baffle, if replacement is required. 12. Remove pump well fill slot baffle only if necessary. 13. Remove rear vacuum break control and bracket assem­ bly by removing (2) screws from bracket and rotating LIGHT TRUCK SERVICE MANUAL the assembly to remove vacuum break rod from slot in plunger head (Fig. 6C4-20). The non-adjustable vac­ uum break rod, riveted to the intermediate choke lever, is not removed at this tim e, but is removed after removal of the choke assembly from the float bowl. Choke Disassembly The non-adjustable choke cover design is used to discourage readjustment of the choke thermostatic cover and coil assembly in the field. However, it is necessary to CARBURETOR MODEL M 4M 6C 4-21 ATTACHING SCREWS REAR VACUUM BREAK C H O K E COVER RETAINERS VACUUM BREAK ROD (NON —ADJUSTABLE) Fig. 6C 4 -2 1 --C h o ke Rivets Fig. 6 C 4 -20--R ear Vacuum Break-Typical remove the cover and coil assembly during normal car­ buretor disassembly for cleaning and overhaul using proce­ dures described below. A T T A C H IN G CHOKE H O U S IN G SCREW Rem oval of Choke Cover 1. Support float bowl and throttle body as an assembly on a suitable holding fixture such as Tool J-9789-118. 2. Carefully align a # 2 1 drill (.159") on rivet head and drill only enough to remove rivet head (Fig. 6C4-21). Drill the two (2) remaining rivet heads and then use a drift and small hammer to drive the remainder of the rivets out of the choke housing. Use care in drilling to prevent damage to choke cover or housing. 3. Remove the two conventional retainers, retainer with tab, choke cover gasket, and choke cover assembly from choke housing. Do not remove baffle plate from beneath the thermo­ static coil on the choke cover. 4. Remove choke housing assembly from float bowl by removing retaining screw and washer inside the choke housing (Fig. 6C4-22). The complete choke assembly can be removed from the float bowl by sliding outward. 5. Remove plastic tube seal (hot air models only) from vacuum inlet boss on choke housing. 6. Remove secondary throttle valve lock-out lever from float bow l (6C4-23). 7. Remove lower choke lever from inside float bowl cavity by inverting bowl. 8. To disassemble intermediate choke shaft from choke housing, remove coil lever retaining screw at end of shaft inside the choke housing (Fig. 6C4-22). Then remove thermostatic coil lever from flats on intermedi­ ate choke shaft. Remove intermediate choke shaft from the choke housing by sliding outward. The fast idle cam can now be removed from the intermediate choke shaft (Fig. 6C4-23). Remove the cup seal from inside choke housing shaft hole if the housing is to be immersed in carburetor cleaner. Also, remove the cup seal from the float bowl SCREW Fig. 6 C 4 -2 2 -R e m o v in g Choke Housing plastic insert for bowl cleaning purposes. DO NOT ATTEM PT TO REM OVE PLASTIC INSERT. Float Bowl Disassembly 1. Remove fuel inlet nut, gasket and filter (Fig. 6C4-24). 2. Remove throttle body by removing throttle body to bowl attaching screws (Fig. 6C4-25). 3. Remove throttle body to bowl insulator gasket (Fig. 6C4-26). Throttle Body Disassembly 1. Remove pump rod from throttle lever by rotating rod until tang on rod aligns with slot in lever. LIGHT TRUCK SERVICE MANUAL 6C4-22 CARBURETOR MODEL M4M INTERMEDIATE CHOKE SHAFT SEAi PLASTIC TUBE SEAL (HOT AIR CHOKE MODELS ONLY) INSULATOR GASKET •HROTTLE VALVE LOCKOUT LEVER ST IDLE CAM CHOKE HOUSING l/ACUUIVI fc S K fc A K M U U [MON—ADJUSTABLE) Fig. 6C 4 -2 3 --C h o ke Housing Assembly Fig. 6C4-26--R em oving Insulator Gasket adjusted on the vehicle carefully following factory recommended procedures. Remove idle mixture needle and plug as follows: 1. Make two parallel cuts in the throttle body on either side of the locator points beneath the idle mixture needle plug (manifold side) with a hack saw (Fig. 6C426a). The cuts should reach down to the steel plug but should not extend more than 1/8" beyond the locator points. The distance between the saw marks depends on the size of the punch to be used. Fig. 6C4-24--Fuel Filter Jk lifc;.*,- THROTTLE BODY TO BOWL SCREWS (3) 2. Place a flat punch at a point near the ends of the saw marks in the throttle body. Holding the punch at a 45° angle, drive it into the throttle body until the casting breaks away, exposing the steel plug. 3. Holding a center punch vertical, drive it into the steel plug. Then holding the punch at a 45° angle, drive the plug out of the casting. Hardened plug will break rather than remaining intact. It is not necessary to remove the plug completely; instead, remove loose pieces. 4. Repeat procedure for the remaining mixture needle. Further disassembly of the throttle body is not required for cleaning purposes. The throttle valve screws are perma­ nently staked in place and should not be removed. The throttle body is serviced as a complete assembly. CLEANING AND INSPECTION Fig. 6C4-25--R em oving Throttle Body Screws 2. Do not remove the plugs covering idle mixture needles during normal carburetor cleaning and servicing unless diagnosis indicates the carburetor is the cause of a driver complaint or emission failure, or the idle mixture needles or throttle body must be replaced, in which case, the plugs may be removed and the idle mixture LIGHT TRUCK SERVICE MANUAL The carburetor parts should be cleaned in cold immer­ sion type cleaner. NOTICE: The electric solenoid, rubber parts, plastic parts, diaphragms, pump plungers, should not be put in immersion type cleaner as they will swell, harden or distort. CARBURETOR MODEL M4M 6C4-23 FLAT PUNCH SAW SLOTS CENTER PUNCH STEP #2 LOCATOR POINTS STEP #1 HACKSAW RECESSED IDLE MIXTURE NEEDLE AND PLUG LOCATIONS Fig. 6 C 4 -2 6 a ~ ld le M ixture N eedle 1. Thoroughly clean all metal parts and blow dry with compressed air. M ake sure all fuel passages and metering parts are free of burrs and dirt. 2. Check, repair or replace the following parts if the following problems were encountered. a. Flooding 1. Inspect float needle seat for dirt, deep wear grooves, scores and proper seating. 2. Inspect float, float arm and hinge pin for distor­ tion, binds and burrs. Check float for leaks and/or being loaded (heavier than normal). b. Hesitation 1. Inspect pump plunger for cracks, scores or cup, excessive wear. A used pump cup will shrink when dry. Soak in fuel for 8 hours before testing if dried out. 2. Inspect pump duration and return spring for being weak or distorted. 3. Check all pump passages and jets for dirt, im­ proper seating inlet or discharge balls, scores in pump well. 4. Check pump linkage for excessive wear, repair or replace as necessary. c. Hard Starting - Poor Cold Operation 1. Check choke valve and linkage for excessive wear, binds or distortion. 2. Inspect choke vacuum diaphragm for leaks. 3. Clean or replace carburetor filter. 4. Inspect needle for sticking, dirt etc. 5. Examine fast idle cam for wear or damage. 6. Also check items under "flooding ". d. Poor Performance - Poor Gas Mileage 1. Power Piston, power valve, metering rods for dirt, sticking, binding, damaged parts or excessive wear. 2. Check air valve for binds and damage. If air valve is damaged, the air horn assembly must be re­ placed. A torsion spring kit is available for repairs to air valve closing spring. A new plastic secondary metering rod cam is included in the kit. e. Rough Idle 1. Inspect gasket and gasket mating surfaces on castings for damage to sealing beads, nicks, burrs and other damage. 2. Clean all idle fuel passages. 3. If removed, inspect idle mixture meedles for ridges, burrs, or being bent. 4. Check throttle lever and valves for binds, nicks, and other damage. LIGHT TRUCK SERVICE MANUAL 6C4-24 CARBURETOR MODEL M 4M 5. Check all diaphragms for possible ruptures or leaks. 6. Clean plastic parts only in cleaning solvent - never in gasoline. The intermediate choke shaft lever and fast idle cam are in correct relation when the tang on lever is beneath the fast idle cam. Do not install choke cover and coil assembly until inside coil lever is adjusted. ASSEMBLY 1. If removed, install idle mixture needle, washer, and spring using Idle Mixture Adjusting Tool J-29030. Lightly seat needle and then back out 4-1/2 turns as a preliminary idle mixture adjustment. Final idle mix­ ture adjustment must be made on car using the procedures described under Idle Mixture Adjustment. 2. Install lower end of pump rod in throttle lever by aligning tang on rod with slot in lever. End of rod should point outward toward throttle lever. Float Bowl Assembly 1. Install new throttle body to bowl gasket over two locating dowels on bowl. 2. Install throttle body making certain throttle body is properly located over dowels on float bowl, then install throttle body to bowl screws and tighten evenly and securely (Fig. 6C4-25). 3. Place carburetor on proper holding fixture J-8328. 4. Install fuel inlet filter spring, filter, new gasket and inlet nut and tighten nut to 24 N-m (18 ft. lbs.) (Fig. 6C424). The fuel inlet check valve on a vehicle with light duty emissions must be installed in the filter to meet Motor Vehicle Safety Standards (M .V .S .S .) for roll-over. New service replacement filter includes the check valve. Ribs on closed end of filter element prevent filter from being installed incorrectly unless forced. Tightening beyond specified torque can damage nylon gasket. Float Bowl 1. Install end of vacuum break rod in slot in rear vacuum break plunger (Fig. 6C4-20). Then, install rear vacuum break and bracket assembly on float bowl using two large countersunk attaching screws. Tighten secure­ ly.If vacuum break adjustment is necessary, see adjustments. 2. If removed, install air baffle in secondary side of float bowl with notches toward the top. Top edge of baffle must be flush with bowl casting. 3. If removed, install baffle in pump well fill slot. 4. Install pump discharge check ball and retainer in passage next to pump well. Tighten retainer securely. 5. Install primary main metering jets (if removed). 6. Install aneroid cavity insert into float bowl. 7. Install new needle seat assembly, with gasket. 8. To make adjustment easier, bend float arm upward at notch in arm before assembly. Install needle by sliding float lever under needle pull clip-correct installation of the needle pull clip is to hook the clip over the edge of the flat on the float arm facing the float pontoon (Fig. 6C4-28). With float lever in pull clip, hold float assem bly at toe and install retaining pin from aneroid cavity side (ends of retain­ ing pin face the accelerating pump well). Do not install float needle pull clip into holes in float arm. 9. Adjust float level as follow s: Choke 1. Install new cup seal into plastic insert on side of float bowl for intermediate choke shaft. Lip on cup seal faces outward. 2. Install secondary throttle valve lock-out lever on boss on float bowl with recess in hole in lever facing inward. 3. Install new cup seal into inside choke housing shaft hole. Lips on seal face inward, towards inside of housing. 4. Install fast idle cam onto the intermediate choke shaft (steps on fast idle cam face downward) (Fig. 6C4-23). 5. Carefully install fast idle cam and intermediate choke shaft assembly through seal in choke housing; then install thermostatic coil lever onto flats on intermediate choke shaft. Inside thermostatic choke coil lever is properly aligned when both inside and outside levers face towards fuel inlet. Install inside lever retaining screw into end of intermediate choke shaft. Tighten securely. 6. Using Tool J-23417, install lower choke rod lever into cavity in float bowl. Install plastic tube seal into cavity on choke housing before assembling choke housing to bowl. Install choke housing to bowl sliding intermedi­ ate choke shaft into lower choke lever (Fig. 6C4-27). LIGHT TRUCK SERVICE MANUAL CHOKE ROD J23417 lever Fig. 6C4-27--lnstalling Choke Rod Lever CARBURETOR MODEL M 4M 6C4-25 Air Horn to Bowl Installation 1. Holding down on air horn gasket at pump plunger location, carefully lower air horn assembly onto float bowl making sure that the bleed tubes, accelerating well tubes, pull-over enrichment tubes (if used), and pump plunger stem are positioned properly through the holes in the air horn gasket. Do not force the air horn assembly onto the bowl but rather lightly lower in place. Fig. 6C4-28--Pull Clip Location 10. 11. 12. 13. 14. 15. a. Hold float retainer firmly in place. b. Push float down lightly against needle. c. With adjustable T-scale, gage from top of float bowl casting (air horn gasket removed) to top of float gauging point 3/16" back from end of float at toe. d. Bend float arm as necessary for proper adjustment by pushing on pontoon. Refer to adjustment for specification. e. Visually check float alignment after adjustment. Install plastic filler block over float needle, pressing downward until properly seated. Install power piston spring in power piston well. If main metering rods were removed from hanger, reinstall making sure tension spring is connected to top of each rod. Install power piston assembly in well (aligning pin on piston with slot in well) with metering rods properly positioned in metering jets. Press down firmly on plastic power piston retainer to make sure the retainer is seated in recess in bowl and the top is flush with the top of the bowl casting. If necessary, using a drift punch and small hammer, tap retainer lightly in place. Install pump return spring in pump well. Install pump plunger stem seal if removed. Install air horn gasket by carefully sliding tab of gasket around main metering rods and beneath the power piston hanger. Position gasket over the two dowel pins on the float bowl. Carefully lift one corner of the air horn gasket and install pump plunger in the pump well by pushing the plunger to the bottom of the well against return spring tension. While holding in this position, align pump plunger stem with hole in gasket and press gasket in place. Air Horn 1. If used, install new pump plunger stem seal in air horn casting (Fig. 6C4-32a). Lightly stake seal retainer in three places, choosing locations diferent from the original stakings. 2. Install two long air horn screws with lockwashers, and two countersunk screws located next to the venturi area. Install secondary air baffle beneath screw number 3 and 4. All air horn screws must be tightened evenly and securely. See Figure 6C 4-29 for proper tightening sequence. 3. Install air valve rod into slot in lever on the end of the air valve shaft. Then, install the other end of rod in hole in front vacuum break diaphragm plunger. Install front vacuum break on air horn using two attaching screws. Tighten screws securely. 4. Connect upper end of pump rod to pump lever by placing rod in specified hole in lever. Align hole in pump lever with hole in air horn casting using J-25322. Using small screwdriver, push pump lever roll pin back through casting until end of pin is flush with casting bosses in air horn (Fig. 6C4-30). Use care installing the small roll pin to prevent damage to pump lever casting bosses. 5. Install two secondary metering rods into the secondary metering rod hanger (upper end of rods point toward each other). Install secondary metering rod holder, with rods, onto air valve cam follower. Install retaining screw end tighten securely. Work air valves up and down several times to make sure they are free in all positions. AIR HORN SCREW T IG H T E N IN G S EQ U E N C E - QUADRAJET Fig. 6 C 4 -2 9 --A ir Horn Screw Tightening Sequence LIGHT TRUCK SERVICE MANUAL 6C4-26 CARBURETOR MODEL M4M a. Place cam follower on highest step of fast idle cam. b. Install the thermostatic cover and coil assembly, and gasket (if used), in the choke housing, making sure coil tang engages inside coil pick-up lever. On M 4M E models, ground contact for the electric choke is provided by a metal plate located at the rear of the choke cover assembly. Do not install a choke cover gasket between the electric choke assembly and the choke housing. c. Align notch in choke cover with retainer tab (2 o’clock position, Fig. 6C4-31). Install blind rivet in retainer and choke housing using riveting tool. d. Install the remaining (2) retainers and blind rivets, similarly. e. On hot air choke models, torque the choke heat pipe nut to 95 in./lbs. 8. Install hose on front vacuum break and on tube on float bowl. 9. Position idle speed solenoid and bracket assembly on float bowl, retaining with two large countersunk screws. Tighten screws securely. Fig. 6C 4-30--lnstalling Pump Lever Pivot Pin 6. Connect check rod into lower choke lever inside bowl cavity; they install choke rod into slot in upper choke lever and retain the choke lever to the end of the choke shaft with attaching screw. Tighten securely. When properly installed, the lever will point to the rear of the carburetor and the number on the lever will face outward (Fig. 6C 4-31). Make sure that the flats on the end of the choke shaft align with flats in the choke lever. The choke coil pick up lever (inside the choke housing) must be indexed properly before installing the choke cover and coil assembly. Also, if necessary, the fast idle cam (choke rod) relation adjustment and front and rear vacuum break adjustments should be performed before installing the choke cover and coil assembly. 7. After the inside thermostatic coil lever, fast idle cam (choke rod), and front and rear vacuum break adjust­ ments have been checked, install the cover and coil assembly in choke housing as follows: LIGHT TRUCK SERVICE MANUAL RIVETS A N D RETAINERS Fig. 6 C 4 -3 T -C h o k e Cover - Typical CARBURETOR MODEL M4M 6C4-27 ADJUSTMENT SPECIFICATIONS - QUADRAJET MODEL M 4 M C - M 4M E - CARBURETOR PART NUM BER FLOAT LEVEL PUMP ROD LOCATION PUMP ROD SETTING FAST IDLE CAM (CHO KE ROD) AIR VALVE ROD VACUUM BREAK FRONT VAC UUM BREAK REAR AIR VALVE W INDUP UNLOADER 17080212 3/8" INNER 9/32" 46° .025" 24° 30° 3/4 40° 17080213 17080215 17080298 17080507 17080512 17080513 17081200 17081201 17081205 17081206 17081220 17081226 17081227 17081290 17081291 17081292 17081506 17081508 17081524 3/8" 3/8" 3/8" 3/8" 3/8" 3/8" 15/32" 15/32" 15/32" 15/32" 15/32" 9/32" 37° .025" 37° 37° 37° .025" .025" .025" 30° 30° 30° 30° 1 1 1 1 40° 9/32" 9/32" 9/32" 23° 23° 9/32" 46° 37° 46° 46° .025" 30° 9/32" 9/32" 9/32" 3/4 3/4 9/32" 46° 9/32" 46° 46° 13/32" INNER INNER INNER INNER INNER INNER INNER INNER INNER INNER INNER INNER INNER INNER INNER INNER INNER INNER 13/32" OUTER 13/32" OUTER 17081526 15/32" 15/32" 13/32" 13/32" 13/32" 13/32" .025" .025" .025" .025" .025" 23° 23° 24° 23° 24° 23° 23° 23° 30° 23° 23° 23° 40° 40° 40° 7/8 7/8 7/8 7/8 40° 40° 42° 42° 42° .025" 23° 23° 23° 46° .025" 9/32" 9/32" 9/32" 9/32" 46° 46° 46° 46° .025" .025" 24° 24° 23° 23° 23° 23° 24° 24° 23° 24° 9/32" 9/32" 46° .025" 23° 36° 7/8 7/8 7/8 46° .025" 7/8 46° .025" 23° 25° 36° 5/16" 36° 7/8 38° 25° 36° 7/8 38° 9/32" 9/32" 5/16" 46° .025" .025" .025" 42° 7/8 42° 7/8 7/8 7/8 42° 42° 42° 42° 42° 36° 36° Fig. 6C 4-32--A djustm ent Specifications LIGHT TRUCK SERVICE MANUAL 6C4-28 CARBURETOR MODEL M 4M PROPANE IDLE MIXTURE SPECIFICATIONS ENG INE 5 .0 L (3 0 5 C I D ) E N G IN E F A M IL Y TRANSM ISSION M A X IM U M ENG INE (E N R IC H E D ) SPEED * A U T O M A T IC 20 R P M A U T O M A T IC 40 R PM 18L4 H H N A RPO LF3 C A N D G S E R IE S MANUAL 5 .0 L (3 0 5 C I D ) E X C . C S E R IE S E N G IN E F A M IL Y W /4 S P E E D 18L4 H A N A O V E R D R IV E RPO LE9 C, K A N D G S E R IE S 100 R P M MANUAL C S E R IE S 150 R P M W /4 S P E E D O V E R D R IV E 5 .0 L (3 0 5 C I D ) E N G IN E F A M IL Y A U T O M A T IC 50 RPM 18Y4 H G N RPO LE9 MANUAL 150 R P M C S E R IE S 5 .7 L (3 5 0 C I D ) A U T O M A T IC 2 0 -5 0 R P M E N G IN E F A M IL Y 18L4 H A N A A N D 18L4 H H N A RPO LS9 C, K A N D G S E R I E S MANUAL * R P M A B O V E ID L E S P E E D S H O W N O N E M IS S IO N L A B E L LIGHT TRUCK SERVICE MANUAL 100 R P M FUEL SYSTEM 6C5-1 SECTION 6C5 FUEL SYSTEM CONTENTS Fuel Filter.......................................................................... ..6C5-1 Fuel Pump.......................................................................... ..6C5-1 Fuel Tank..............................................................................6C5-4 Cleaning Fuel S y stem .......................................................6C5-8 Fuel Feed and Vapor Pipes..............................................6C5-9 Evaporative Control System .......................................... ..6C5-10 Accelerator C ontrols....................................................... ..6C5-12 Specifications.......................................................................6C5-15 Angle to Decimal Conversion....................................... ..6C5-16 Special Tools...................................................................... ..6C5-17 FUEL FILTER GENERAL DESCRIPTION All engine fuel filters are located in the carburetor fuel inlet. These fuel filter elem ents are of pleated paper. Elements are placed in the inlet hole with the gasket surface outward. A spring holds the element outward, sealing it by compressing a gasket surface against the inlet fitting. ON-VEHICLE SERVICE The carburetor inlet fuel filter should be replaced at intervals shown in Section OB. A plugged filter and/or check valve will restrict fuel flow. After assembling any filter element in the carburetor, always start the engine and check for leaks in the fuel line and fittings before installing the air cleaner. abnormal amount of sediment or water; the tank should therefore be removed and thoroughly cleaned. Fuel Filter Replacement 1. 2. 3. 4. 5. O th e r Filters or Strainers A woven plastic filter is located on the lower end of the fuel pickup pipe in the gas tank. This filter prevents dirt from entering the fuel line and also stops water unless the filter becomes completely submerged in water. This filter is self cleaning and normally required no maintenance. Fuel stoppage at this point indicates that the gas tank contains an 6. 7. 8. Disconnect fuel line connection at fuel inlet filter nut. Remove fuel inlet filter nut from carburetor. Remove filter and spring. If removed, install check valve in fuel inlet filter. The fuel inlet check valve must be installed in the filter to meet Motor Vehicle Safety Standards (M .V .S.S.) for roll-over. N ew service replacement filter must include the check valve. Install fuel inlet filter spring, filter, and check valve assembly in carburetor. Check valve end of filter faces toward fuel line. Ribs on closed end of filter element prevent filter from being installed incorrectly unless forced. Install new gasket on fuel inlet filter nut and install nut in carburetor. Tighten nut to 24 N-m (18 ft. lbs.). Tightening beyond specified torque can damage gasket. Install fuel line and tighten connection. Start engine and check for leaks. FUEL PUMP GENERAL DESCRIPTION Low Pressure Complaint The fuel pump (Figs. 6C5-1 through 6C 5-5) is a diaphragm type pump and is actuated by the rocker arm through a link and a push rod. The only way to check fuel pump pressure is by connecting an accurate pressure gage to the fuel line at carburetor level. Never replace a fuel pump without first making that simple check. Some vehicles have a fuel pump with an outlet for a vapor return system. Any vapor which forms is returned to the fuel tank along with hot fuel through a separate line. This greatly reduces any possibility of vapor lock by keeping cool fuel from the tank constantly circulating through the fuel pump. DIAGNOSIS Complete diagnosis of all possible causes of the trouble prior to replacement of the fuel pump will save time, expense and possible causes of the trouble prior to replacement of the fuel pump will save time, expense and possibly prevent a repeat complaint. Not Enough Fuel Flow Complaint When an engine has a "starving-out"- condition, many mechanics jump to the conclusion that the fuel pump is not pumping enough fuel. Many times the "starving-out" condition is actually due to a weakness in the ignition system, since these two troubles are very hard to separate. Even when an engine is starving for fuel, the cause is more likely to be a plugged fuel filter or a restricted fuel line than a malfunctioning fuel pump. LIGHT TRUCK SERVICE MANUAL 6C5-2 FUEL SYSTEM ON-VEHICLE SERVICE Inspection and Test If the fuel system is suspected of delivering an improper amount of fuel to the carburetor, it should be inspected and tested in the vehicle, as follows: Inspection of Fuel System 1. Make certain that there is fuel in the tank. 2. With the engine running, inspect for leaks at all fuel feed hose connections from fuel tank to carburetor. Tighten any loose connections. Inspect all hoses for flattening or kinks which would restrict the flow of fuel. Air leaks or restrictions on suction side of mechanical fuel pump will seriously affect pump output. 3. Inspect for leaks at fuel pump diaphragm flange. 4. Disconnect feed pipe near carburetor. 5. Disconnect distributor connectors so that engine can be cranked without firing. Place suitable container at end of pipe and crank engine a few revolutions. If no fuel, or only a little flows from pipe, the feed line is clogged or fuel pump is inoperative. Before condemning the fuel pump, disconnect feed line at both ends and blow through it with air hose to make certain that fuel pump is operating within specifications. Fuel Pum p Pressure Test 1. Disconnect fuel line at pump and connect a suitable pressure gage . 2. Start engine and check pressure with engine running at slow idle speed. Fuel pump pressure should be as specified at the end of this section On vehicles equipped with a vapor return system, squeeze off the return hose so that an accurate reading can be obtained. 3. If fuel pump pressure is below minimum, pump must be replaced. Fuel Pum p Flow Test 1. Disconnect fuel line from carburetor. Run fuel line into a suitable measuring container. 2. While observing the sweep second hand of a clock or watch, run the engine at idle until there is one pint of fuel in the container. One pint should be pumped in 30 seconds or less. 3. If flow is below minimum, check for restriction in the line. Rem oval 1. Disconnect fuel inlet hose from pump. Disconnect vapor return hose, if so equipped. 2. Disconnect fuel outlet pipe. 3. Remove two bolts holding fuel pump. 4. Remove fuel pump, push rod, gasket and mounting plate (if used). LIGHT TRUCK SERVICE MANUAL Installation 1. Install push rod, gasket, mounting plate (if used) and fuel pump. 2. Install two hex head bolts, turning them alternately and evenly. 3. Install fuel outlet pipe. If it is difficult to start fitting, time can be saved by disconnecting upper end of pipe from carburetor. Tighten fitting securely, meanwhile holding fuel pump nut with a wrench. Install and tighten fitting at carburetor, if removed. 4. Install fuel inlet hose and clamp. Install vapor return hose and clamp, if so equipped. 5. Start engine and check for leaks. FUEL SYSTEM 6C5-3 30 N.m (22 F T .-L B S .) BO TH E N D S O F P IP E G ASKET 37 N.m (27 F T .-L B S .) PUSH ROD PLUG 7.4L (LE-8) Fig. 6C5-5--Fuel Pum p--7.4 L LIGHT TRUCK SERVICE MANUAL 6C5-4 FUEL SYSTEM FUEL TANK ON-VEHICLE SERVICE O utside Fram e Rail Fuel T an kCab a n d C rew ca b (Figs. 6 C 5 -6 an d 8) 1. 2. 3. 4. Drain tank. Disconnect fuel lines, meter wire and ground lead. Remove strap supports (lines, vent) and clip. Loosen clamps from filler neck and vent line. LIGHT TRUCK SERVICE MANUAL 5. Remove strap bolts and lock washers from tank front and rear locations on inside frame rail. 6. Remove tank from frame simultaneously disengaging filler neck hose from filler neck (Fig. 6C5-8 and 6C59). 7. Remove meter assembly from fuel tank using Tool J-24187 (Fig. 6C5-10). 8. Reverse removal procedure to install fuel tank. FUEL SYSTEM SIDE M EM BER 6C5-5 R.H. PLATFO RM ASSEM BLY H O S E -V E N T STRAP BRACKET CLAM P HOSE-FILLER Fig. 6 C 5 -9 —Filler N eck-C ab Stake Body Fig. 6C5-8--Fuel Tank Filler neck (03 & 43) Fig. 6C5-10--R em oving M ete r Assembly LIGHT TRUCK SERVICE MANUAL 6C5-6 FUEL SYSTEM C enter a n d A u xilia ry Fuel Tank CK 10 and 20 (06, 16) (Figs. 6C 5-11, 12) G Van (Fig. 6C5-13). 1. Drain tank. 2. Raise vehicle on hoist. 3. Unclamp upper filler neck and vent tube hose (Fig. 6C5-8 and 9). 4. Unclamp gage unit hoses at frame end. 5. Support tank and remove support straps. 6. Lower tank and disconnect meter wire. 7. Remove tank. 8. Install in the reverse order, using new antisqueak material. 9. Lower vehicle and remove from hoist. Fig. 6C5-13--Fuel Tank Installation G Van LIGHT TRUCK SERVICE MANUAL FUEL SYSTEM 6C5-7 Fig. 6C5-14--Fuel Tank and Filler Neck G Van LIGHT TRUCK SERVICE MANUAL 6C5-8 FUEL SYSTEM CLEANING FUEL SYSTEM C leanin g SPACER ■STRAP ASSEMBLY AN TI-SQ U EAK CEMENT SPACER TORQUE AT 10 FT. LBS. ASSEMBLY: Cem ent anti-squeak to upper surface of tan k flan ge w ith 1.00 w ide coverage before installation of tan k assembly. Tighten upper nut a fte r low er nut has been tightened. Fig. 6C 5-15--F uel Tank and M ounting - P10 Fram e M o u n te d Fuel Tan k - P M o del (Figs. 6 C 5 -1 5 , 16, 17) 1. 2. 3. 4. 5. Drain tank. Remove filler neck. Disconnect meter unit fuel line and wiring. Remove bolts attaching tank supports to frame. Remove tank complete with mounting bracket and support straps. 6. Remove tank from brackets and support straps, if necessary. 7. Install in reverse order and replace antisqueak material. LIGHT TRUCK SERVICE MANUAL If trouble is due to contam inated fuel or foreign material that has been put into the tank, it can usually be cleaned. If tank is rusted internally, it should be replaced. 1 . Disconnect battery negative cable and distributor feed wire. 2. Drain fuel tank. 3. Remove fuel tank. 4. Remove fuel inlet filter at carburetor and inspect for contamination. If filter is plugged replace (leave fuel line disconnected). 5. Locate tank away from heat, flame, or other source of ignition. Remove fuel gage tank unit and inspect condition of filter. If filter is contaminated a new filter should be installed upon reassembly. 6. Complete draining of tank by rocking it and allowing fuel to run out of tank unit hole. 7. Purge fuel tank with steam or running hot water for at least five minutes. Pour water out of tank unit hole (rock tank to assure complete removal of water). This procedure will not remove fuel vapor. Do not attempt any repair on tank or filler neck where heat or flame is required. 8. Disconnect inlet fuel line at pump and use air pressure to clean fuel line and fuel return line (if equipped). Apply air pressure in the direction fuel normally flows through line. 9. Use low air pressure to clean pipes on tank unit. 10. Clean filter on fuel tank unit, if required. Install fuel tank gage unit, (with new gasket) into tank and install tank. Connect tank unit wires and all fuel lines, except pump to carburetor line (see "Removal of Tank" for proper procedure). 11. Connect a hose to fuel line at carburetor; insert other end of hose into a one gallon fuel can. 12. Connect battery cable. Make sure distributor feed wire is disconnected. 13. Put six gallons of clean fuel in tank and operate starter to pump two quarts of fuel into fuel can. This will purge fuel pump. 14. Remove hose and connect fuel line to carburetor. 15. Connect distributor feed wire. 16. Check all connections for leaks. FUEL SYSTEM 6C5-9 Fig. 6C 5-17--Fuel Tank (5 0 G a l.) M ete r and Filler Neck - P30 FUEL FEED AND VAPOR PIPES GENERAL DESCRIPTION Fuel feed pipes are secured to the underbody with clamp and screw assemblies. Flexible hoses are located at fuel tank fuel, vapor and return lines and fuel pump. The pipes should be inspected occasionally for leaks, kinks or dents. If evidence of dirt or foreign material is found in carburetor, fuel pump or pipes, pipe should be disconnected and blown out. Dirt or foreign material may be caused by a damaged or omitted fuel strainer in fuel tank. 6C5-10 FUEL SYSTEM ON-CAR SERVICE Fuel Line Repair Replacem ent 1. If replacement of a fuel feed, fuel return or emission pipe is required use welded steel tubing meeting GM Specification 124-M or its equivalent. 2. Do not use copper or aluminum tubing to replace steel tubing. Those m aterials do not have satisfactory durability to withstand normal vehicle vibrations. 3. When rubber hose is used to replace pipe, use only reinforced fuel resistant hose which meets GM Speci­ fication 6165-M . Hose inside diameter must match pipe outside diameter. 4. Do not use rubber hose within 4" (100 mm) of any part of the exhaust system or within 10" (254 mm) of the catalytic converter. 5. In repairable areas, cut a piece of fuel hose 4" (100 mm) longer than portion of the line removed. If more than a 6 inch (152 mm) length of pipe is removed, use a combination of steel pipe and hose so that hose lengths will not be more than 10 inches (254 mm). Follow the same routing as the original pipe. 6. Cut ends of pipe remaining on car square with a tube cutter. Using the first step of a double flaring tool, form a bead on the end of both pipe sections. If pipe is too corroded to withstand bead operation without damage, the pipe should be replaced. If a new section of pipe is used, form a bead on both ends of it also. 7. Use screw type hose clamp, Part Number 2494772, or equivalent. Slide clamps onto pipe and push hose 2" (51 mm) onto each portion of fuel pipe. Tighten clamps on each side of repair. 8. Pipes must be properly secured to the frame to prevent chafing. EVAPORATIVE CONTROL SYSTEM (ECS) GENERAL DESCRIPTION Canister and Filter All light duty emissions and some heavy duty emission vehicles are equipped with a system designed to prevent escape of fuel vapor to the atmosphere. Vapor generated by evaporation of fuel in the tank, previously exhausted to atmosphere, is transferred by an emission line to the engine compartment. During periods of operation, vapors are fed directly to the engine for consumption. During periods of inoperation, an activated charcoal canister located in the emission line stores any vapor generated for consumption during the next period of operation. Rem oval The amount of vapor drawn into the engine at any time is too small to have any effect on fuel economy or engine operation. With this closed system it is extremely important that only vapors be transferred to the engine. To avoid the possibility of liquid fuel being drawn into the system, these following features are included as part of the total system: 1. A fuel tank overfill protector is provided on all series to assure adequate room for expansion of liquid fuel volume with temperature changes. 2. A one point fuel tank venting system is provided on all series to assure that the tank will be vented under any conceivable vehicle attitude. 3. To protect the tank from mechanical damage in the event of excessive internal or external pressures result­ ing from the operation of this closed system, a pressurevacuum relief valve, located in the gas cap, will control the tank internal pressure. ON-VEHICLE SERVICE Maintenance requirement is that the oiled fiberglass filter assembled in the bottom of the canister, be replaced at intervals shown in Section 0B. Under extrem ely dusty conditions, more frequent attention may be required. Check operation of bowl vent and purge valve. 1. 2. 3. 4. Note installed position of hoses on canister. Disconnect hoses from top of canister. Loosen clamps and remove canister. If replacing filter, pull out filter from bottom of canister with your fingers. Inspection 1. Check hose connection openings. Assure that they are open. 2. Check operation of purge valve by applying vacuum to the valve. A good valve will hold vacuum. Installation 1. Install new filter. 2. Install canister and tighten clamp. 3. Connect hoses in same order. Canister Purge Valve Disassembly 1. Disconnect lines at valve. 2. Snap off valve cap (slowly remove cap as diaphragm is under spring tension). Remove diaphragm, spring retainer and spring. 3. Replace parts as necessary. Check orifice openings. Assembly 1. Install spring, spring retainer, diaphragm and cap. 2. Connect lines to valve. Checking Purge V alv e 1. Remove purge valve control vacuum line. Check for a vacuum signal with engine operating above idle (1500 RPM ). If no vacuum signal, perform EGR System Function Check. 2. Apply an external vacuum source to the purge valve control diaphragm. A good valve will hold vacuum. FUEL SYSTEM 3. If the valve will not hold vacuum, replace canister. 4. If valve holds vacuum, remove purge line and check for vacuum. If no vacuum, check PCV hoses and system. Repair ir replace as necessary. Checking Bowl V e n t V a lv e 1. Remove the bowl vent vapor hose from the carburetor. 2. Check the open condition of the valve by connecting to a manual vacuum pump. It should not be possible to obtain .5 inch Hg if the valve is open. 3. If a high resistance or plugged system is found, check for a plugged or restricted hose. Hose may be cleared with compressed air. If the hose is clear, remove the canister filler. If the restriction persists, replace the canister. 4. A simple check of the valve closed condition can be obtained with the same procedure as in Step 2, but with the engine operating at operating temperature. M ani­ fold vacuum will be applied to the valve through the control line. The bowl vent line should exhibit a plugged condition. 5. If the valve is not closed, remove the control vacuum line and check for vacuum. If no vacuum is present, check hose for restriction or vacuum leak. Repair or replace as required. If vacuum is present, replace canister. 6C5-11 Pressure Checking E vaporative Control System 1. Stabilize vehicle by operating until warmed up. 2. Remove tank line at canister and observe for liquid in the line. Hook-up pressure device. 3. Apply 15 " H 20 pressure to the fuel vapor line. A.Observe for excessive loss of pressure. B .If negligible pressure loss occurs observe for fuel vapor smell or fuel loss at points listed in Diagnostics under Possible Cause. C.Remove fuel filler cap(s) and observe for pressure in tank(s). 4. Remove fuel cap (LH on duel tank units) and blow on vent line to check for obstructions. (Install LH cap on dual tank units and remove RH cap. Repeat above.) Fuel Tank Selector Valve R eplacem ent (Fig. 6 C 5 -1 7 a ) 1. Disconnect battery. 2. Remove hose shield and brace. 3. Remove fuel and vapor hoses noting their position for later installation. 4. Remove two screws holding valve to frame and remove valve. 5. Install valve and tighten screws. 6. Install fuel and vapor hoses in same positions noted at removal. 7. Install brace and hose shield. 8. Connect battery. Fig. 6C5-17a--Selector Valve LIGHT TRUCK SERVICE MANUAL 6C5-12 FUEL SYSTEM ACCELERATOR CONTROLS GENERAL The accelerator control system is cable type. There are no linkage adjustments. A reference between the bottom of accelerator pedal and floor pan should be used only as a check for bent bracket assembly. Check torque references. Check for correct opening and closing positions by operating accelerator pedal and if any binding is present, check routing of cable. ACCELERATOR CONTROL CABLE Refer to figures 6C5-18 through 6C5-21 for removal and installation of accelerator control cable. P ACCELERATOR PEDAL Refer to figures 6C5-22 through 25 for removal and installation of accelerator pedal. CAUTION Cable is not to be kinked or damaged in any way during assembly operation. SUPPORT ENGINE SEALER OUTER SPRING CABLE RETAINER' NOTE With Inner Spring inside Outer Spring , anchor both springs thru nylon bushing in carburetor lever and hole in support. CAUTION Flexible components (hoses, wires, conduits, etc) must not be routed within 2.00 inches of moving parts of accelerator linkage forward of support unless routing is positively controlled. Fig. 6 C 5 -18--A ccelerato r Controls L6-Light Duty Emissions LIGHT TRUCK SERVICE MANUAL Fig. 6 C 5 -19--Accelerator Controls L6-Heavy Duty Emissions. FUEL SYSTEM C A U T IO N Flexible components (hoses, wires, conduits, etc) must not be routed within 2 inches of moving parts of accelerator linkage forward of Support, unless routing is positively controlled. k. STUD 6C5-13 N O T E Route Cabl e over spark plug wires. , — C A U T IO N Cable is not to be kinked c damaged in any way during assembly operation. SEALER .. CARB LEVE « - I Conduit fitting at both ends must have locking tangs expanded & locked in attaching hole. CARB RETAINER N O TE N O TE Springs can be installed with' hook ends inboard or outboard. INNER SPRING With Inner Spring inside Outer Spring, anchor both Springs thru nylon bushing in Carburetor Lever and hole in Support. Fig. 6C 5-20--A ccelerator Controls V8-2Bbl. 1 CAUTION 1 Flexible components (hoses, wires, conduits, etc.), must not be routed within 2 inches of moving parts Of accelerator linkage forward of Support unless routing is positively controlled. CABLE ASSEMBLY I NOTE 1 Cable is not to be kinked or damaged in any way during assembly. SPRING OUTER CARBURETOR STUD FASTENER l± _____ QF SPRING INNER NOTE | With Inner Spring inside Outer Spring, anchor both Springs thru hole in Carburetor Lever and holes in Support and Bracket. Fig. 6C 5-21--A ccelerator Controls V8-4Bbl. LIGHT TRUCK SERVICE MANUAL 6C5-14 FUEL SYSTEM CAUTION: Care must be used in pressing Retainer into hole in Rod to assure Cable is not kinked or damaged in any way. I NOTE I Slip accelerator control cable thru slot in Rod. Install retainer, being sure it is seated. I CAUTION! Care must be used in pressing the retainer into hole in Rod to assure cable is not kinked or damaged in any way LE ASSEMBLY SUPPORT, SPRING REINFORCEMENT PEDAL*— 1T ill'll j1 / — L N U I U Retainer must bear against pedal rib. NOTE I Having secured all components ot tne accelerator linkage as specified, linkage must operate freely without bind between full closed throttle and full wide open throttle. TIGHTEN TO 27 IN. LBS. Fig. 6 C 5 -22--A ccelerato r Pedal-CK NOTE: Slip a ccelerato r control cable thru slot in rod. Install retainer, being sure it is s e a te d ..^ ^ ^ RETAINER SPRING (SHOWN IN LOADED POSITION) PEDAL 'C A U T IO N : C are must be used in pressing the retainer into hole in rod to assure cable is not kinked or d am aged in any LUBRICATE Fig. 6 C 5 -23--A ccelerato r Pedal-G W° y- ^REINFO RCEM ENT ROD SUPPORT SPRING' REINFORCEMENT ACCELERATOR CO NTRO L CABLE T IG H T E N T O PEDAL 5 0 IN . LBS. TIGHTEN TO 42 IN. LBS. SUPPORT Fig. 6 C 5 -24--A ccelerato r Pedal-P42 Fig. 6C 5-2 5 --A cc e le ra to r Pedal-P32 LIGHT TRUCK SERVICE MANUAL FUEL SYSTEM 6C5-15 SPECIFICATIONS FUEL PUMP PRESSURE ENGINE P.S.I. L6 (ALL) 4V2-6 V8 (ALL) WITHOUT VAPOR RETURN LINE 71/2-9 V8 (EXC LF8) WITH VAPOR RETURN LINE 51/2-7 V8 (LF8) WITH VAPOR RETURN LINE 71 /2-9 TORQUE SPECIFICATIONS IM E C A R B U R E TO R TORQUE (IN. LBS.) SCREW SCREW TORQUE (IN. LBS.) AIR HORN TO BOWL 45 FUEL INLET NUT AIR CLEANER BRIDGE 70 FAST IDLE CAM 50 CHOKE LEVER 25 PUMP LEVER 30* THROTTLE BODY TO BOWL 180 NEEDLE SEAT 45 METERING JET 40 400 *Loctite AVV or equivalent M2M - M4M C A R B U R ETO R SCREW TORQUE (IN. LBS.) THROTTLE BODY THROTTLE BODY TO BOWL 46 CHOKE HOUSING CHOKE LEVER CHOKE HOUSING ATTACHING CHOKE HOUSING COVER 14 46 26 AIR HORN AIR HORN TO BOWL 10-32 AIR HORN TO BOWL 8-32 AIR HORN TO THROTTLE BODY CHOKE LEVER VACUUM BREAK UNIT FUEL INLET NUT NEEDLE SEAT METERING JET SOLENOID BRACKET 46 26 46 14 26 400 45 40 71 Fig. 6C5-26--Specifications LIGHT TRUCK SERVICE MANUAL 6C5-16 FUEL SYSTEM ANGLE DEGREE TO DECIMAL CONVERSION MODEL M2MC, M2ME AND M4MC CARBURETOR THE RELATION BETWEEN DECIMAL AND ANGLE TOLERANCES OF THE COMPONENT PARTS. THIS WHO HAS ACCESS TO PLUG GAUGES ONLY. THE ACCURACY AND BEST OVERALL PERFORMANCE READINGS IS NOT EXACT DUE TO MANUFACTURING CHART IS SUPPLIED FOR USE BY THE MECHANIC RECOMMENDED TOOL IS AN ANGLE GAUGE FOR AND EMISSIONS. D E C IM A L E Q U IV . D E C IM A L E Q U IV . ANGLE DEG REES TOP OF V A L V E ANGLE DEG REES TOP OF V A L V E 5 .023 33 .203 6 .028 34 .211 7 .033 35 .220 8 .038 36 .227 9 .043 37 .234 10 .049 38 .243 11 .054 39 .251 12 .060 40 .260 13 .066 41 .269 14 .071 42 .277 15 .077 43 .287 16 .083 44 .295 17 .090 45 .304 18 .096 46 .314 19 .103 47 .322 20 .110 48 .332 21 .117 49 .341 22 .123 50 .350 23 .129 51 .360 24 .136 52 .370 25 .142 53 .379 26 .149 54 .388 27 .157 55 .400 28 .164 56 .408 29 .171 57 .418 30 .179 58 .428 31 .187 59 .439 32 .195 60 .449 Fig. 6 C 5 -2 7 --A n gle to Decim al Conversion FUEL SYSTEM 6C5-17 SPECIAL TOOLS Idle Mixture Socket................................................................................ J-29030-B Adjustable Float G age........................................................................... J-9789-90 Bending T ool.......................................................................................... J-9789-111 Needle Valve Seat Remover..................................................................... J-22769 Carburetor S tand.................................................................................. J-9789-1 18 Float Level G age.................................................................................... J-9789-130 Float Level G age................................................................................... J-9789-135 Carburetor Choke Angle Gage............................................................. J-26701-4 Hand Vacuum D evice................................................................................ J-23738 Thermae Thermometer.............................................................................. J-22973 Carburetor Gage S e t................................................................................ J-9789-C Fuel Tank Sending Unit Remover.......................................................... J-24187 LIGHT TRUCK SERVICE MANUAL ' a b mwn jam S.iiix:?.’ .. .... I ■......... ll> ........ .... ‘Jt j " ’ , ,r * - . •’ » ENGINE ELECTRICAL 6D-1 SECTION 6D ENGINE ELECTRICAL CONTENTS Electric Choke Heater....................................................... General Electrical System Diagnosis............................. Battery.................................................................................. Charging System ................................................................ Ignition S y stem .................................................................. 6D-1 6D-1 6D-5 6D-8 6D-18 Diesel Engine..................................................................... Conventional E ngine....................................................... Cranking System ................................................................ Specifications....................................................................... 6D-18 6D-33 6D-53 6D-67 ELECTRIC CHOKE HEATER-OIL PRESSURE SWITCH 'OIL" LIGHT FUSIBLE LINK j —cTVo— ! 1 "GAUGE' FUSE CARB. CHOKE HEATER 1*3 ir — I ■((— ||l- IGNITION SWITCH 01L PRESSURE SWITCH Fig. 6D-1 A--Electric C hoke Heater D iag ra m All engines have a two-terminal oil pressure switch (sending unit) for controlling current to the electric choke heater. This switch and its associated circuitry provide for the illumination of the "Oil" tell tale lamp in the event of loss of oil pressure or loss of voltage at the choke heater. The diagram in Figure 6D-1A shows how the dual function is accomplished. The "Bulb Check" feature is same as present system. That is, with ignition switch in "Run" position with engine off. This circuit will also indicate continuity in the choke heater and its connector. If "Oil" tell tale lamp illuminates with engine running, it could indicate one or more of the following: 1. Loss of oil pressure. 2. Loss of choke heater voltage. 3. Blown GAGE fuse. ELECTRIC CHOKE HEATER CHECKING PROCEDURE 1. Allow choke to cool so that when throttle is opened slightly, choke blade fully closes. This check must be performed with engine not running and at an ambient temperature of (60°C to 27°C). 2. Start engine and determine time for choke blade to reach full open position. (Start timer when engine starts). 3. If the choke blade fails to open fully within 3.5 minutes, proceed with steps 4-5-6 below. 4. Check voltage at the choke heater connection. (Engine must be running). If the voltage is approximately 12-15 volts, replace the electrical choke unit. 5. If the voltage is low or zero, check all wires and connections. If any connections in the oil pressure switch circuitry are faulty or if the oil pressure switch is failed open, the oil warning light will be on with the engine running. Repair wires or connections as required. 6. If all wiring and connections are good, replace oil pressure switch. No gasket is used between the choke cover and the choke housing because of grounding requirements. GENERAL ELECTRICAL SYSTEM DIAGNOSIS The diagnosis in figures 6D-2A and 6D-3A can be used to find electrical system - faults. Once a fault has been traced to a particular component, refer to that components section of the service manual. LIGHT TRUCK SERVICE MANUAL 6D-2 ENGINE ELECTRICAL NO CRANKING, NO SOUND FROM SOLENOID 3634 Fig. 6D-2A--Electrical System Diagnosis LIGHT TRUCK SERVICE MANUAL ENGINE ELECTRICAL 6D-3 Fig. 6D-3A--Electrical System Diagnosis LIGHT TRUCK SERVICE MANUAL 6D-4 ENGINE ELECTRICAL Wiring JUNCTION BLOCK TEMPERATUR GAGE SENDER POWER UNIT W/S WIPER MOTOR OIL PRESS SWITCH exc Z53 TAIL COMBINATION EXTENSION WIRE |THROTTLE /KICKER . ENDER ASM W/GAGE PACK ■SPEED SWITCH TEMPERATURE SWITCH CONNECTOR CK 100+200 FORWARD LAMP HARNESS VIEW B Fig. 6D-4A--Engine Speed Switch LIGHT TRUCK SERVICE MANUAL VIEW A ENGINE ELECTRICAL 6D-5 BATTERY General Description......................................................... .. 6 D -1 General Information....................................................... 6D-1 Common Causes of Failure........................................ .6 D -1 Electrolyte F reezing..................................................... 6 D -1 Carrier and Hold D ow n...............................................6D-1 Ratings..............................................................................6D-6 Built In H ydrom eter..................................................... 6D-6 Diagnosis............................................................................... 6D-6 On-Vehicle Service............................................................. 6D-7 Charging Procedure ......................................................... 6D-7 Jump Starting................................................................... 6D-7 Remove and Replace....................................................... 6D-8 GENERAL DESCRIPTION The sealed battery (see Fig. 6D-1B) is standard on all vehicle lines (see Specifications for specific applications). There are no vent plugs in the cover. The battery is completely sealed, except for two small vent holes in the side. These vent holes allow the small amount of gas produced in the battery to escape. The battery has the following advantages over conventional batteries: B U ILT-IN H YD RO M ETER 1. N o water addition for the life of the battery. This improvement makes the sealed battery possible. 2. Overcharge protection. If too high a level voltage is applied to the battery, it will not accept as much current as a conventional battery, the excess voltage will cause gassing, which leads to liquid loss. 3. Reduced self-discharge compared to a conventional battery. This is important when a battery is left standing for long periods of time. 4. Comparable power available in a lighter and smaller case. The battery has three major functions in the electrical system. Fig. 6D-1 B~Sealed Top Battery First, it is a source of electrical energy for cranking the engine. Second it acts as a voltage stabilizer for the electrical system. And third, it can, for a limited time, provide energy when the electrical load exceeds the output of the generator. GENERAL INFORMATION COMMON CAUSES OF FAILURE A battery is not designed to last indefinitely; however, with proper care, it will provide many years of service. If the battery tests good but fails to perform satisfactorily in service, the following are some of the more important factors that may point to the cause of the trouble. 1. Accessories left on overnight. 2. Slow average driving speeds for short periods. 3. The cars electrical load is more than the generator output particularly with the addition of after market equipment such as radio equipment, air conditioning, window defoggers or light systems. Electrolyte Freezing The freezing point of electrolyte depends on its specific gravity. Since freezing may ruin a battery, it should be protected against freezing by keeping it in a fully charged condition. Carrier and Hold-Down The battery carrier and hold-down should be clean and free from rust before installing the battery. The carrier should be in good condition so that it will support the battery securely and keep it level. 4. Defects in the charging system such as electrical shorts slipping fan belt, faulty generator or voltage regulator. Make certain there are no parts in carrier before installing the battery. 5. Battery abuse, including failure to keep the battery cable terminals clean and tight or loose battery hold down. See On Vehicle Service for torque specifications. To prevent the battery from shaking in its carrier, the h old -d ow n bolts sh ou ld be tight. S ee On V eh icle Serv­ ic e for torq u e sp ecifica tio n s. LIGHT TRUCK SERVICE MANUAL 6D-6 ENGINE ELECTRICAL Visual Inspection The external condition of the battery should be checked periodically for damage such as cracked cover or case. RATINGS A battery has two ratings: (1) a reserve capacity rating at 80°F (27°C) which is the time a fully charged battery will operate the car with no generator operation, (2) a cold crank rating at 0°F (18°C) which indicates the cranking load capacity. (See Specifications for specific battery ratings). The Ampere/Hour rating formerly found on batteries was based on the reserve capacity rating and is no longer used. Built-In Hydrometer The sealed battery has a built-in temperature compen­ sated hydrometer in the top of the battery. This hydrometer is to be used with the following diagnostic procedure. When observing the hydrometer, make sure that the battery has a clean top. A light may be required in some poorly-lit areas to see the right indication. Under normal operation, two indications can be ob­ served (see Figure 6D-2B): 1. G REEN DOT VISIBLE Any green appearance is interpreted as a green dot and the battery is ready for testing. 2. DARK; G REEN DOT N O T VISIBLE If there is a cranking complaint, the battery should be tested as described in the Diagnosis section. The charging and electrical systems should also be checked at this time. Occasionally, a third condition may appear: 3. CLEAR OR LIGHT YELLOW This means the fluid level is below the bottom of the hydrometer. This may have been caused by excessive or prolonged charging, a broken case, excessive tipping or normal battery wearout. When finding a battery in this condition, it may indicate high charging voltage caused by a faulty charging system and therefore, the charging and electrical system may need to be checked. If a cranking complaint exists and is caused by the battery, it should be replaced. Replace battery. Do not charge, test or jump-start. C A U T IO N :D o not charge, test or jum p start b a tte ry w h e n th e h ydrom eter is clear or lig h t ye llo w . N ot fo llo w in g this ca u tio n could result in serious personal injury (p articu larly to eyes) or property d a m a g e from b a tte ry explosion or b attery acid. DIAGNOSIS The following procedure should be used for testing batteries: 1. VISUAL INSPECTION INSULATOR STRAP PREVENTS TOOL SEPARATION A ND LOSS WHEN NOT IN USE Check for obvious damage, such as cracked or broken case or cover, that could permit loss of electrolyte. If obvious damage is noted, replace the battery. Determine cause of damage and correct as needed. If not, go to step 2. 2. HYDROMETER CHECK (Fig. 6D-2B) a. GREEN DOT VISIBLE - go to step 3. b. DARK; G R EEN DOT NOT VISIBLE. Charge the battery as outlined under Charging Proce­ dure section and proceed to Step 3. 3. LOAD TEST Load testing may require use of battery side terminal adapters to insure good connections (see Fig. 6D-3B). a. Connect a voltmeter and a battery load tester across the battery terminals. LIGHT TRUCK SERVICE MANUAL ADAPTER CHARGING TOOL ATTACHED TO TERMINALS Fig. 6D-3B--Side Terminal Battery Adapters ENGINE ELECTRICAL MINIM UM VOLTAGE B A TTER Y Y 85-4 R85-5 R87-5 R89-5 9.6 9.5 9.4 9.3 9.1 8.9 8.7 8,5 TEST LOAD 130 170 210 230 AMPS AMPS AMPS AMPS 6D-7 TEMPERATURE °F °C 70 60 50 40 30 20 10 0 21 *16 10 4 - 1 - 7 -1 2 -1 8 Fig. 6D-5B--M inim um V o lta ge D rop 2996 Fig. 6 D -4 B ~ Lo a d Test Values b. Apply 300 ampere load for 15 seconds to remove surface charge Remove load. c. Wait 15 seconds to let battery recover and apply specified load from load test chart. Read voltage after 15 seconds, then remove load. d. If voltage does not drop below the minimum listed in Fig. 6D-5B, the battery is good. Temperature of the battery will change the minimum voltage to pass the load test. See Temperature vs. voltage drop Chart, and estimate the temperature the battery has been exposed to for the last several hours. ON-VEHICLE SERVICE CHARGING PROCEDURES When it is necessary to charge the battery, the follow­ ing safety precautions must be followed: 1. DO NOT CHARGE battery if hydrometer is clear or light yellow. Replace battery. 2. If the battery feels hot 125°F (52°C), or if violent gassing or spewing of electrolyte through the vent hole occurs, discontinue charging or reduce charging rate. Charge the battery until the green ball appears. Tipping or shaking the battery may be necessary to make the green ball appear. Temperature of the battery will effect the charging rate, and most charging equipment will not charge at a constant rate. For example, if the charger starts at 30 amperes and drops off to 10 amperes after 1 hour, the average current for that hour was 20 amperes. The actual boost charge was 20 ampere-hours. The sealed battery can be fast charged or slow charged with ordinary chargers in the same manner as conventional batteries. Either method will restore the battery to full charge. Many chargers have special settings for sealed batter­ ies. These settings reduce the charge voltage and limit the current. It is not necessary to use these settings with this sealed battery. JUMP STARTING IN CASE OF EMERGENCY WITH AUXILIARY (BOOSTER) BATTERY N O TIC E: Do not push or tow this vehicle to start. Damage to the emission system and/or to other parts of the vehicle may result. Both booster and discharged battery should be treated carefully when using jumper cables. Follow the procedure outlined below, being careful not to cause sparks: C A U T IO N :D ep artu res from these conditions or the procedure b elo w could result in: 1.Serious personal injury (particularly to eyes) or property d a m a g e from such causes as b a tte ry explosion, b a tte ry acid, or electrical burns; a n d / or 2 . D a m a g e to electronic com ponents of e ith e r vehicle. N ever expose b a tte ry to open fla m e or electric spark - batteries g e n e ra te a gas w hich is fla m ­ m ab le a n d explosive. Remove rings, w atches, a n d other jew elry . W e a r ap p ro ved eye protection. Do not a llo w b a tte ry flu id to contact eyes, skin, fabrics, or p a in te d surfaces - it is a corrosive acid. Flush a n y contacted a re a w ith w a te r im m e d ia te ly an d thoroughly. Be careful th a t m e tal tools or jum per cables do not contact th e positive b a tte ry term in a l (or m e ta l in contact w ith it) an d a n y other m e ta l on th e car, because a short circuit could occur. Batteries should a lw a y s be kept out of the reach of children. 1. Set parking brake and place automatic transmission in PARK (N E U T R A L for manual transmission.) Turn off lights, heater, and other electrical loads. 2. Check the built-in hydrometer. If it is clear or light yellow, replace the battery, do not attempt to jump start. 3. Only 12 volt batteries can be used to start this engine. 4. Hook up one end of the positive jumper cable to the positive terminal of the booster battery and the other end to the positive terminal of the discharged battery. DO NOT PERMIT vehicles to touch each other as this could cause a ground connection and counteract the benefits of this procedure. 5. Hook up one end of the negative jumper cable to the negative terminal of the booster battery, and the other LIGHT TRUCK SERVICE MANUAL 6D-8 ENGINE ELECTRICAL end to a solid engine ground (such as A /C compresser or generator mounting bracket) at least 450 mm (18 inches) from the battery of the vehicle being started (DO NO T C O N N E C T DIRECTLY TO THE N EG ­ ATIVE T E R M IN A L OF THE DEAD BATTERY). 6. Start the engine of the vehicle that is providing the jump start and turn off electrical accessories. Then start the engine in the car with the discharged battery. 7. Reverse these directions exactly when removing the jumper cables. The negative cable must be removed from the engine that was jump started first. REMOVE AND REPLACE 1. Hydrogen gas is produced by the battery. A flame or spark near the battery may cause the gas to ignite. 2. Battery fluid is highly acidic. Avoid spilling on clothing or other fabric. Any spilled electrolyte should be flushed with large quantities of water and cleaned immediately. To remove or replace a battery, always disconnect the negative cable first, then the positive cable. Torque battery cables at battery to 12 Nm (9 lb. ft.). Two types of battery hold-downs are used. The hold-down rod going across the battery top should be torqued to 3.0 N-m (25 lb. in.), and the clamp which holds the bottom of the battery should be torqued to 16.0 N-m (12 lb. ft.). When handling a battery, the following safety precau­ tions should be observed: CHARGING SYSTEM General Description............................................................ Diagnosis............................................................................... Faulty Indicator Lamp Operation............................... Undercharged Battery..................................................... Overcharged Battery............................................... ....... On-Vehicle Service............................................................. Unit Repair.......................................................................... Disassembly....................................................................... 6D-8 6D-10 6D-12 6D-12 6D-13 6D-13 6D-14 6D-14 Stator C hecks................................................................... Rotor Field Winding C hecks........................................ Diode Trio C heck............................................................ Rectifier Bridge Check.................................................... Brush Holder and Regulator Replacem ent............... Slip Ring Servicing......................................................... Bearing Replacement and Lubrication....................... Reassembly.......................................................... ............. 6D-14 6D-14 6 D -15 6D-15 6D-15 6D-16 6D-16 6D-16 GENERAL DESCRIPTION The basic charging system is the SI integral regulator charging system (Fig. 6D -1C ). The internal components are connected electrically as shown in Fig. 6D-2C. The genera­ tor is connected to the vehicle electrically as shown in Fig. 6D-3C. The 15-SI generator is similar to the 10-SI except that: 1. It is slightly larger physically. 2. It produces 70 amps output at full speed. 3. It uses different drive end and slip ring end bearings. 4. The stator uses delta windings, which cannot be checked for opens. The brown field wire to the generator is used to initially activate the generator. The 10 ohm resistance, provided by either the generator warning lamp or the resistance wire with optional gages, is needed to protect the diode trio. Although several models of generators are available with different outputs at idle and different maximum outputs, their basic operating principles are the same. The generator features a solid state regulator that is mounted inside the generator slip ring end frame. All regulator components are enclosed into a solid mold, and this unit along with the brush holder assembly is attached to LIGHT TRUCK SERVICE MANUAL the slip ring end frame. The regulator voltage setting never needs adjusting, and no means for adjustment is provided. The generator rotor bearings contain a supply of lubricant sufficiently adequate to eliminate the need for periodic lubrication. Two brushes carry current through the two slip rings to the field coil mounted on the rotor, and under normal conditions will provide long periods of attention-free service. The stator windings are assembled on the inside of a laminated core that forms part of the generator frame. A recitifier bridge connected to the stator windings contains six diodes, and electrically changes the stator a.c. voltages to a d.c. voltage which appears at the generator output terminal. Generator field current is supplied through a diode trio which also is connected to the stator windings. A capacitor or condenser, mounted in the end frame protects the rectifier bridge and diode trio from high voltages, and suppresses radio noise. N o periodic adjustments or maintenance of any kind are required on the entire generator assembly. NOISY GENERATOR Noise from a generator may be caused by a loose drive pulley, loose mounting bolts, worn or dirty bearings, defective diode, or defective stator. ENGINE ELECTRICAL 6D-9 Fig. 6 D -1 C --1 0 S I G enerator Fig. 6D-2C--Regulator in Charging Circuit LIGHT TRUCK SERVICE MANUAL 6D-10 ENGINE ELECTRICAL VOLTMETER (R A L L Y GAUGE ONLY) GENERATOR WARNING LAMP (EXC. R ALLY GAUGE) SWITCH BATTERY BROWN (FIELD) 10 ohms RESISTANCE' WIRE (R A LLY GAUGE ONLY) [U - .............. 10 ohms RED (SENSING) BULKHEAD CONNECTOR GENERATOR Fig. 6 D -3 C --C h a rg in g Circuit - SI System DIAGNOSIS Most charging system troubles show up as a faulty indicator lamp, an undercharged or an overcharged battery. Since the battery itself may be defective, it should be checked first to determine its condition. Also, in the case of an undercharged battery, check for battery drain caused by grounds or by accessories being left on. A basic wiring diagram showing lead connections is shown in Figure 6D-3C. To avoid damage to the electrical equipment, always observe the following precautions: • Do not polarize the generator. • Do not short across or ground any of the terminals in . the charging circuit except as specifically instructed. • Never operate the generator with the output terminal open circuited. • Make sure the generator and battery are of the same ground polarity. LIGHT TRUCK SERVICE MANUAL • When connecting a charger or a booster battery to the vehicle battery, see Battery Charging Section. • In some circuits (Gage option), a voltmeter may be used instead of an indicator lamp. In this case, Section "A" pertaining to faulty indicator lamp operation should be omitted from the troubleshooting procedure. Trouble in the charging system will show up as one or more of the following conditions: A. Faulty indicator lamp operation. B. An undercharged battery as evidenced by slow crank­ ing or test indicator dark. C. An overcharged battery as evidenced by excessive spewing of electrolyte from the vent holes. IN D IC A T O R LAMP O P E R A T IO N TEST NO. 1 Engine Running Ig n itio n Sw itch ON Lam p O ff NORMAL See Test 2 TEST N O .2 Lam p O n NORMAL See Test 3 La m p On C onnect v o ltm e te r to B A T . te rm in al on generator and chassis ground. T u rn ignition key on. Check 10 am p. "G A U G E S " " T R A N S ." fuse in fuse block. Engine S topped Ig n itio n S w itch ON TEST NO. 3 La m p O n D IM L am p O ff Ign. S w itch OFF L a m p O ff NORMAL La m p O n If th e in d ic a to r lam p o p e ratio n is norm al fo r all th re e tests, refer to SI g enerator Diagnosis Check drive b e lt and w irin g connections at generator and batte ry cables. D isconnect N o . 1 and 2 C onn e c to r at generator, G ro u n d N o . 1 w ire. Do N O T ground N o . 2 w ire . Disconnect N o . 1 and 2 C o n n e c to r a t ge n era to r. Fig. 6D-4C--CHarging r La m p On B a tte ry V oltag e Zero V o lta g e I J Disconnect N o . 1 and N o . 2 Connector at generator. C onnect v o ltm e te r fro m N o . 1 c onnec tor to chassis ground. Repair open c irc u it betw een B A T . term inal on generator and junction b lo c k or battery. System D iagnosis La m p b urned o u t. Replace R e c tifie r Bridge in g e n era to r. 1. Disconnect b a tte ry ground strap. 2. Disconnect w ires fro m B A T . term inal on generator. 3. Connect a m m e te r black lead to B A T . te rm in a l wires and red lead to B A T . te rm in a l. 4. Connect b a tte ry ground strap. 5. Turn o n all accessories, lights on high beam , and b lo w e r o n high speed. 6. Run engine as required to o b ta in m a xim um c u rre n t o u tp u t and record am m eter re ad in g .* O u tp u t N O T w ith in 1 0 am ps o f rated output stam p ed on generator fra m e. 1. C o n n e c t N o . 1 and N o . 2 co n n ec to r to generator. 2. Insert screw driver in to test hole to ground r o to r w in d in g . Lam p On L a m p O ff T 1. M a k e sure N o . 1 w ire co n n ec to r is m aking good co n ta ct on te rm in a l. 2. Disassemble generator and check brushes, slip rings and ro to r w inding fo r open. Replace R egulator Insert screw driver in to test hole. End of screw driver m ust to u c h ta b and side o f screwdriver gro u n d against end fra m e. Run engine as b e fo re and recheck o u tp u t. Rem ove generator. R e fe r to G en e ra to r Disassem bly. 2427 6D -11 O u tp u t N O T w ith in 1 0 am ps o f rated o u tp u t stam p ed o n generator fra m e. ELECTRICAL Replace Regulator R e pa ir short betw een N o . 1 and N o . 2 w ires in harness. ENGINE O u tp u t w ith in 1 0 am ps o f rated o u t­ p u t stam ped on generator fram e. L a m p On O pen in N o . 1 w ire fro m generator to ig n itio n sw itch. Repair open c irc u it in N o l 1 w ire fro m c onnec tor to ig n itio n switch. C heck b a tte ry connections and b a ttery c o n d itio n Lam p O ff Install N o . 1 and 2 C o n n e c to r. Zero V oltag e O u tp u t w ith in 10 amps o f rated o u t­ p u t stam ped on generator fram e. N O R M A *. L a m p O ff 1. A p p ro x im a te ly 2 to 4 V o lts * l f b a tte ry is fu lly charged, use the starter to p a rtia lly discharge it before recording m a x im u m c urrent o u tp u t. Check 10 am p. "G A U G E S " " T R A N S ." fuse in fuse b lo c k. 6D-12 ENGINE ELECTRICAL FAULTY INDICATOR LAMP OPERATION UNDERCHARGED BATTERY Check the indicator lamp for normal operation as shown in Fig. 6D-5C. This condition, as evidenced by slow cranking and battery test indicator dark can be caused by one or more of the following conditions even though the indicator lamp may be operating normally. The following procedures also applies to circuits with a voltmeter. If the indicator lamp operates normally, proceed to "Undercharged Battery" section. Otherwise, proceed to either one of the following three abnormal conditions. 1. Switch Off, Lamp On-In this case, disconnect the two leads from the generator No. 1 and No. 2 terminals. If the lamp stays on, there is a short between these two leads. If the lamp goes out, replace the rectifier bridge as covered in the Generator Repair Section. This condition will cause an undercharged battery. 2. Switch On, Lamp Off, Engine Stopped-This condition can be caused by the defects listed in part 1 above, or by an open in the circuit. To determine where an open exists, proceed as follows: a. Check for a blown fuse, or fusible link, a burned out bulb, defective bulb socket, or an open in No. 1 lead circuit between generator and ignition switch. b. If no defects have been found, proceed to Under­ charged Battery section. 3. Switch On, Lamp On, Engine Running-The possible causes of this condition are covered in the "U N D E R ­ CHARGED BATTERY" section. If a defect has been found and corrected at this point, no further checks need be made. 1. Insure that the undercharged condition has not been caused by accessories having been left on for extended periods. 2. Check the drive belt for proper tension (see Section 6B). 3. If a battery detect is suspected, refer to Battery Section. 4. Inspect the wiring for defects. Check all connections for tightness and cleanliness, including the slip connectors at the generator and firewall, and the cable clamps and battery posts. 5. With ignition switch "on" and all wiring harness leads connected, connect a voltmeter from generator " BAT" terminal to ground, generator No. 1 terminal to ground and generator No. 2 terminal to ground. A zero reading indicates an open between voltmeter connection and battery. Generators have a built-in feature which avoids over­ charge and accessory damage by preventing the gener­ ator from turning on if there is an open in the wiring harness connected to the No. 2 generator terminal. Opens in the wiring harness connected between the No. 2 generator terminal and battery may be between the terminals, at the crimp between the harness wire and terminal, or in the wire. 6. If previous Steps 1 through 5 check satisfactorily, check generator as follows: a. Disconnect battery ground cable. Switch Lamp Engine OFF ON ON OFF ON OFF STOPPED STOPPED RUNNING b. Connect an ammeter in the circuit at the "BAT" terminal of the generator. c. Reconnect battery ground cable. d.Turn on radio, windshield wipers, lights high beam and blower motor high speed. Connect a carbon pile across the battery. Fig. 6 D -5 C --ln dicator Lamp O peration INSERT SCREWDRIVER GROUND TAB TO END FRAME END FRAME HOLE e. Operate engine at moderate speed as required, and adjust carbon pile as required, to obtain maximum current output. f. If ampere output is within 10 amperes of rated output as stamped on generator frame, generator is not defective; recheck Steps 1 through 5. g. If ampere output is not within 10 percent of rated output, determine if test hole is accessible (Fig. 6D6C). If accessible go to step h. If not accessible go to step 1. h. Ground the field winding by inserting a screwdriver into the test hole (Fig. 6D-6C). NOTICE: Tab is within 3/4 inch (19mm) of casting surface. Do not force screwdriver deeper than one inch (25mm) into end frame to avoid damaging the tab. L Operate engine at moderate speed as required, and Fig. 6 D -6 C --G e n e ra to r Test Hole LIGHT TRUCK SERVICE MANUAL adjust carbon pile as required to obtain maximum current output. ENGINE ELECTRICAL j. If output is within 10 amperes of rated output, check field winding as covered in Generator Repair section, and test regulator with an approved regulator tester, k. If output is not within 10 amperes of rated output, check the field winding, diode trio, rectifier bridge, and stator as covered in the Generator Repair Section. 7. If test hole is not accessible, disassemble generator and make tests listed in Unit Repair section. OVERCHARGED BATTERY 1. To determine battery condition refer to Battery section. 6D-13 2. Connect a voltmeter from generator No. 2 terminal to ground. If reading is zero, No. 2 lead circuit is open. 3. If battery and No. 2 lead circuit check good, but an obvious overcharge condition exists as evidenced by excessive spewing of electrolyte, proceed to disassembly section of Generator Overhaul and check field windings for grounds and shorts. If defective, replace rotor, and test regulator with an approved regulator tester. Generator Tester - many testers are available to check the generator. They provide a quick on-vehicle test, and can save time over conventional diagnostic methods. Consult manufacturer’s instructions for usage. ON-VEHICLE SERVICE The generator does not require periodic lubrication. The rotor shaft is mounted on ball bearings at the drive end and roller bearings at the slip ring end, and each contains a permanent grease supply. A t periodic intervals, check mounting bolts for tightness and adjust belt tension (see Sec. 6B). When adjusting belt tension, apply pressure at center of generator, never against either end frame. Rem ove From Vehicle 1. Disconnect negative battery terminal at battery. C A U T IO N :F ailure to observe this step m a y result in an injury from hot b a tte ry lea d a t g en erator. 2. Remove two terminal plug and battery leads on back of generator. 3. Loosen adjusting bolts (see Fig. 6D-6 through 6D-8 for generator mounting). 4. Remove generator drive belt. 5. Remove thru bolt which retains generator. 6. Remove generator from vehicle. Install In Vehicle 1. If removed from vehicle, install generator to mounting bracket with bolts, washers and nuts. Do not tighten. 2. Install generator drive belt. 3. Tighten belt to the specified belt tension. See Engine Cooling Section for proper belt tensioning procedures. 4. Tighten bolts to 41 N-m (30 lb. ft.), except bolt at sliding slots on brackets which is 27 N-m (20 lb. ft.). 5. Install generator terminal plug and battery leads to generator. 6. Connect negative battery terminal. LIGHT TRUCK SERVICE MANUAL 6D-14 ENGINE ELECTRICAL UNIT REPAIR 10SI, 15SI AND 27SI GENERATORS DISASSEMBLY, TEST AND REASSEMBLY (GENERATOR REMOVED FROM ENGINE) T H R U -B O L T LO C A TIO N NO. 1 TERMINAL T E S TIN G STA TO R (CHECK FOR OPENS) OH NO. 2 TERMINAL "BAT TERMINAL THRU-BOLT TEST HOLE 1. Make scribe marks on end frames to facilitate reassem­ bly. 2. Remove four thru-bolts and separate drive end frame as­ sembly from rectifier end frame assembly. END FR A M E V IE W RESISTOR (USED ON OME MODELS) INSULATING WASHERS OHMMETER (CHECK FOR GROUNDS) 5. On 10SI only, check stator for opens with ohmmeter (two checks). If either reading is high (infinite), replace stator. 6. On all series, check stator for grounds. If reading is low, replace stator. T E S T IN G RO TO R (CHECK FOR GROUNDS) (OHMMETER) RECTIFIER BRIDGE _ __ DIODE CAPACITOR ■«> .«v,n.n.vi NUTS TR|0 3. Remove three attaching nuts and regulator attaching screws. 4. Separate stator, diode trio and regulator from end frame. NOTE: The regulator cannot be tested on the work bench except with a regulator tester. OHMMETER CHECK FOR OPENS 7. Check rotor for grounds with ohmmeter. Reading should be very high (infinite). If not, replace rotor. 8. Check rotor for opens. Should read 2.4-3.5 ohms, If not, replace rotor. Fig. 6D-7C--Generator Unit Repair LIGHT TRUCK SERVICE MANUAL ENGINE ELECTRICAL 6D-15 BRUSHES RETAINED IN HOLDER TESTING TRIO OHMMETER BRUSH RETAINER BRUSHES SINGLE CONNECTOR 14. Clean brushes with soft, dry cloth. 15. Put brushes in holder and hold with brush retainer wire DRIVE END BEARING (Some models use flat washer instead of slinger) THREE CONNECTORS END FRAME 9. To check diode trio, connect ohmmeter as shown, then reverse lead connections. Should read high and low. If not, replace diode trio. 10. Repeat same test between single connector and each of other connectors. BEARING TESTING RECTIFIER BRIDGE BRUSH HOLDER SLINGER REGULATOR ARMATURE SHAFT To remove rotor and drive end bearing, remove shaft nut, washer and pulley, fan and collar. Push rotor from hous­ ing. Remove retainer plate inside drive end frame and push bearing out. Clean all parts with soft cloth. Press against outer race to push bearing in. Fill cavity between retainer plate and bearing with Part No. 1948791 lubricant. Assemble retainer plate. Press rotor into end frame. Assemble collar, fan, pulley, washer and nut. Torque shaft nut to 40-60 lb.-ft. (54-82 NM) [/ X INSULATED HEATSINK GROUNDED HEATSINK ^ ^ V----- Vl INSULATING WASHER RETAINER COLLAR / y BEARING COLLAR ________OHMMETER 11. Check rectifier bridge with ohmmeter connected from grounded heat sink to flat metal on terminal. Reverse leads. If both readings are the same, replace rectifier bridge. 12. Repeat test between grounded heat sink and other two flat metal clips. 13. Repeat test between insulated heat sink and three flat metal clips. To replace bridge, remove attaching screws. ROTOR SHAFT END FRAME SCREW Fig. 6D-8C--Generator Unit Repair LIGHT TRUCK SERVICE MANUAL 6D-16 ENGINE ELECTRICAL RECTIFIER END BEARING 15SI SERIES USE TH IN W ALL TUBE IN SPACE BETWEEN GREASE CUP AND HOUSING TO PUSH BEARING IN FLUSH W ITH HOUSING ' P AR TIA L W R EC TIFIER END FRAME 15S1/100 20. Push slip ring end bearing out from outside toward inside of end frame. 21. On 10SI and 27SI, place flat plate over new bearing, press from outside toward inside until bearing is flush with end frame. 22. On 15SI, see illustration. 23. Assemble brush holder, regulator, resistor, diode trio, rectifier bridge and stator to slip ring end frame. 24. Assemble end frames together with thru-bolts. Remove brush retainer wire. Fig. 6D-9C--Generator Unit Repair LIGHT TRUCK SERVICE MANUAL ENGINE ELECTRICAL 6D-17 generator must be dismantled and the regulator removed for further testing. 1. Turn the tester OFF. 2. Make sure a regulator is not installed in the Tester regulator holder. 3. Plug the on-vehicle testing accessory cable into the accessory socket on the Tester front panel. 4. Disconnect the regulator connector from the generator. Then plug the on-vehicle testing accessory cable in its place. Connect the ground lead (alligator clip) to the generator case. 5. Test the generator/regulator circuit using steps 2, 3, 4 and 15 of the instruction label located on the inside of the case cover. If you do not obtain the proper lamp and/or voltmeter indication, or if either or both lamps flicker on and off when you perform these steps, the regulator must be removed from the generator for further testing to determine whether the problem is in the generator or in the regulator. Fig. 6 D -1 0 C --V o lta ge Regulator Tester BRUSH HOLDER AND REGULATOR REPLACEMENT To determine if the regulator is defective, an approved regulator tester must be used. After removing the three attaching nuts, the stator, and diode trio screw, the brush holder and regulator may be replaced by removing the two remaining screws. Note the two insulators located over the top of the brush clips and that these two screws have special insulating sleeves over the screw body above the threads. The third mounting screw may or may not have an insulat­ ing sleeve. If not, this screw must not be interchanged with either one of the other two screws, as a ground may result, causing no output or uncontrolled generator output. Regula­ tors may vary in appearance but are com pletely inter­ changeable in these generators. Using voltage regulator tester CTW -1170 or equiv­ alent (Fig. 6D-10C), it is possible to check the voltage regulator both on the vehicle and on the bench. Use the instructions on the tester cover for testing the regulator on the bench and use the following instructions for the on vehicle test and the continuity test. O n -V eh icle Test This on-vehicle test procedure helps to quickly deter­ mine if a problem exists in the generator/regulator circuit. If you do not obtain the proper results in this test, the C o n tin uity Test The continuity test accessory cable is used in conjunc­ tion with the meter on the Tester. A high meter reading indicates an open circuit (no continuity) while a zero meter reading indicates continuity. When you make a continuity test, keep the following points in mind: 1. Make sure a regulator is not installed in the holder. 2. The knob is turned clockwise only until it clicks. 3. All components must be isolated for testing. 4. Make sure voltage is not applied to the component being tested. SLIP RING SERVICING If the slip rings are dirty, they may be cleaned and finished with 400 grain or finer polishing cloth. Spin the rotor, and hold the polishing cloth against the slip rings until they are clean. The rotor must be rotated in order to clean the slip rings evenly. Cleaning the slip rings by hand without spinning the rotor may result in flat spots on the slip rings, causing brush noise. NOTICE: Slip rings which are rough or out of round should be trued in a lathe to .002 inch maximum indicator reading. Remove only enough material to make the rings smooth and round. Finish with 400 grain or finer polishing cloth and blow away all dust. LIGHT TRUCK SERVICE MANUAL 6D-18 ENGINE ELECTRICAL SPECIAL TOOLS J-2150 1 PULLY AD AP TER Fig. 6D-11C--Special Tool C IO Se rie s Diesel Engine Electrical DIESEL ELECTRONIC CONTROL SYSTEM General Description Instrumentation The major components of the system are, an electronic control module, engine thermal probe, glow plugs, glow plug relay, fast idle control (with A /C only), fast idle temp switch, fast idle solenoid and auto disengagement lockout relay. Vehicles with the optional diesel engine have special instrumentation indicators to permit the operator to prop­ erly apply the starting procedure. A dual indicator (Don't start/Glow Plugs) light on the I.P. provides this information on engine starting conditions. Diesel Electrical Circuitry Electronic Module The diesel engine electrical circuitry differs from conventional gasoline engines as follows: Operating on electrical signals from the probe, the module controls glow plug operation and determines glow plug power requirements. The electronic module is designed to monitor the system, probe, and associated wiring for malfunctions. Should a malfunction occur, that might result in glow plug damage, the module provides for system shutdown and driver notification. The electronic module provides automatic system shutdown due to a malfunction and disconnects glow plug relay from battery plus and ground. Battery Two 12 volt sealed top batteries connected in parallel are required for the higher electrical load due to the glow plugs and starter. - ,, Starter The starter is larger and designed to crank the engine at least the 100 RPM required for starting. Charging Thermal Probe A Standard generator supplies charging current to both batteries at the same time. There are no switches or relays in the charging circuit. The thermal probe, mounted on the engine in such a position as to sense engine temperature, transmits this information to the electronic module for controlling glow plug operation. Ignition Glow Plugs In the diesel engine, air alone is compressed in the cylinder; then after the air has been compressed a charge of fuel is sprayed into the cylinder and ignition occurs due to the heat of compression. Eight glow plugs are used to preheat the chamber as an aid to starting. They are 6 volt heaters (operated at 12 volts) that turn on when the ignition key is turned to the run position prior to starting the engine. They remain on a short time after starting, then automatically turn off. The glow plugs used in this sytem are 6 volt units operated at system voltage (12 volts), to provide rapid heating. LIGHT TRUCK SERVICE MANUAL Glow Plug Relay The glow plug relay is used to switch power to the glow plugs, on or off, as determined by the electronic module. No attempt should be made to bypass the relay using a jumper cable or other means, as the glow plugs are not designed to ENGINE ELECTRICAL 6D-19 burn continuously and the constant current provided by jumping the relay will cause the glow plug elements to be destroyed. Fast Idle System The fast idle relay increases engine speed at cold start or low engine temperature or with A /C on, and after each ignition cycle. Auto Disengagement Lockout Relay This relay senses "engine running" condition and disengages starter circuitry at start up. STARTER GENERATOR MOUNTING Starter and Generator mounting is illustrated in Figures 6D-7D through 6D-9D. LIGHT TRUCK SERVICE MANUAL 6D-20 ENGINE ELECTRICAL Fig. 6D-1D--C-10 Series Diesel Electrical Schematic LIGHT TRUCK SERVICE MANUAL ENGINE ELECTRICAL 6D-21 .8 YEL-508 (HW) .8 PNK-30(HW) PRODUCTION TANK SENOER Fig. 6D-2D-C-10 Series Diesel Electrical Schematic LIGHT TRUCK SERVICE MANUAL 6D-22 ENGINE ELECTRICAL MODULE CIRCUITS B C - D E - F - A G H J K L M N - - Relay Circuits Circuit Module Terminal Blank Blank 502 - Probe Blank 503 Right Bank Glow Plugs (Monitor) 505 Glow Plug Relay Coil Feed (+) 3 - Ignition 150 Ground (Power) 506 - Glow Plug Relay Coil Feed (-) 506 Glow Plug Relay Coil Feed (-) 505 Glow Plug Relay Coil Feed (+) Glow Plug Feed (Power) B la n k 501 - Probe 5 0 0 Module Logic Ground Generator Output (Monitor) System Operation (at Cold Start) 1 Ignition Switch-Off Don't Start/Glow Plugs Lamp-Off 3 Ignition Switch "Start" Don't Start/Glow Plugs Lp Pulsing on/off 2 Ignition Switch - "Run" Don't Start/Glow Plugs Lp - On 4 Ign Sw Run Don't Start/Glow Plugs Lp Pulsing on/off* *G low Plugs (Don't Start/Glow Plugs Lp) will cycle on/off for a maximum of 30 seconds after engine starts, then turn off, and remain off. LIGHT TRUCK SERVICE MANUAL ENGINE ELECTRICAL 6D-23 ASM Fig. 6 D -3 D --C -1 0 Series Diesel Engine C om partm ent C om pon en t Location LIGHT TRUCK SERVICE MANUAL 6D-24 ENGINE ELECTRICAL B R A K E LAM P IN S T R U M E N T P A N E L S W IT C H W IR IN G H A R N E S S BRAKE PEDAL BEZEL BRACKET O P E N IN G W A R N IN G LAM P IN S T R U M E N T CLU STER VIEW A GROUND BUS BAR A u to m a tic transm ission clutch test connection. VIEW B ________ _ Install C on ne ctor into vacant cavity m arked " i G N 1 . Fig. 6D-5D--Diesel Control M o d u le W irina Fig. 6D-6D--Diesel Engine - A ccelerator Control and Sole noid Assem bly LIGHT TRUCK SERVICE MANUAL Fig. 6D-7D--Diesel Starter M ou n tin g ENGINE ELECTRICAL 6D-25 Fig. 6D -8 D --G e n e rator M ou n tin g - LF9 LIGHT TRUCK SERVICE MANUAL TO IG NITIO N SWITCH ii BATT C KT3PNK Fig. 6D-10D--C-10 GEN CKT 2 RED PRINTED CIRCUIT BOARD RELAY 25 CKT BRN A Series Diesel Electrical System EN G IN E TEM P C PROBE E B D CKT 501 PPI CKT 502 GRA CKT 500 B BJ_K/WHT 500 © © LOGIC GROUND C K T 505 YEL TIM IN G LATCHING AND LEVEL DETECTION CIRCUIT LOGIC. TRANSISTOR SWITCH CKT 506 LT BLU GLOW PLUG RELAY CKT 509 C K T 150 BLK © POWER GROUND ELECTRONIC MODULE CKT 503 B ORN _________ — ■“DO N 'T ST A RT/G LOWPLUGS LAMP BUS BAR GRD D iagn osis <► juuub^jTnnni' > .flinty jtiiiuv . 1980 CK SERIES DIESEL LEFT BANK GLOW PLUGS S IM P LIFIE D WIR. D IA G R A M GLOW PLUG CO NTRO L jJUlfllb* RT BANK GLOW PLUGS ENGINE ELECTRICAL 6D-27 ENGINE DOES NOT START-COLD 1. Fuel system checked and is O K . 2. Battery voltage 12.4 or more (Ignition O F F ) 3. Engine cranking speed O K (100 R P M or more) W IT H IG N IT IO N SW IN " R U N " Listen for G low Plug Relay clicking with cold engine. Relay should come on for approxim ately 6 seconds. (Varies with engine temperature) Then turn off and then pulse O N /O F F . R E L A Y C L IC K S O N /O F F G LO W PLU G R E L A Y N O T C L IC K IN G O N /O F F I I Connect 12 volt test light to ground. Touch glow plug relay terminal with 2 red wires. Test light should turn O N / O F F as relay clicks on/off. Connect 12 volt test light to ground. Touch Yel wire (C K T 5 0 5 ) at G lo w Plug Relay connector light should pulse on and off as above with engine cold. T E S T L IG H T D O E S N O T T E S T L IG H T P U L S E S O N / O F F P U LSE O N /O F F I M om entarily touch a jumper wire from the light blue terminal of the glow plug relay to ground. DOES NOT O PERATE Check 506 circuit from relay to module. W IR IN G O K Replace relay O P E N C IR C U IT I Replace module and check module ground - Proceed to chart page 6D-19. GLO W PLUG R E L A Y O P E R A T E S Repair as necessary T E S T L IG H T N O T T U R N IN G O N / O F F Touch test light to single red wire terminal (batt. fed) on glow plug relay. I 1 1 Touch each glow plug harness connector with 12 volt test light connected to ground. Light should turn on/off. '----1 Ir/, 1 T 1 OFF ON ON ST E A D Y Relay contacts shorted, replace relay & glow plugs as required. Locate and repair open circuit in wire from glow plug relay to battery Replace relay i., L IG H T P U L S E S O N / O F F \>t i- 1 ON A L L 8 Disconnect harness from all 8 plugs. Connect test light to 12 v source and touch each glow plug terminal. Light should be on. Replace glow plug if light is not on. - .1 NO T ON ONE OR M O RE Repair open circuit in glow plug harness. If open circuit caused by burned wire, glow plug is shorted, replace as necessary. Fig. 6D-11D--C-10 Series Diesel Electrical System Diagnosis LIGHT TRUCK SERVICE MANUAL 6D-28 ENGINE ELECTRICAL W ITH IG N ITIO N ON, CHECK VOLTAG E AT C A V IT Y F OF MODULE (CKT 505) I 12 VOLTS OR MORE 0 VOLTS Repair open circuit in yellow wire from module to relay Check for ground at cavity H of module (C K T 150 blk) I NO GROUND I GOOD GROUND Repair wiring as required Check voltage at cavity G of module (CKT 3-Pnk) with ignition ON I 12 VOLTS OR MORE 0 VOLTS I I Check the voltage at cavity C (C K T 502 Gray) of the module Repair open in pink wire (C K T 3) from module to Ign. Switch. -------------------- , I LESS THAN 6 VOLTS 12 VOLTS OR MORE I I Turn ignition O F F , remove probe connector, measure resistance between probe terminals C and D. Measure voltage at module connectors F and J 1 I I OPEN CIRCUIT LESS THAN 20 OHMS Replace the probe Reconnect bulkhead connector, remove module. With Ign. ON check voltage at module connector cavity C ......... * 2 TO 8 VOLTS (F) 2 TO 8 VOLTS (J) I Measure voltage at module connector cavity M -NO C O NTINUITY r 502 circ. (G R A ) open from probe to module READS CO N TIN U ITY J___________ --------1 0 VOLTS LESS THAN 1 VOLT I I Replace module 500 circuit is open in module jumper or engine harness Reconnect probe. Disconnect 12 terminal bulkhead connector and measure resistance to ground of the 502 circuit (Gray) in the engine harness. I LESS THAN 10 OHMS I 0 VOLTS ■Reconnect bulkhead connector,1 — I remove module. With Ign. ON Replace the module check voltage at module connector cavity C 12 VOLTS OR M ORE' I 502 circuit is shorted to batt circuit in harness I----------------- I ___ I__ I I 0 - OHMS 3 OHMS I Replace relay and module I Remove module check terminal in cavity J for damage I ____ L 12 VOLTS (F) 1 VO LT (J) I Disconnect probe and measure resistance between probe terminals E to D with Ign. OFF Measure Glow Plug Relay coil resistance _________ L _ ----------------------------- 1 I LESS THAN 1 VOLT, BOTH 12 VOLTS (F)/12 VOLTS (J) OR 2 VOLTS (F)/2 VOLTS (J) I I Measure voltage to ground at Glow Plug Relay coil terminal 2 way connector (Y e ll/L t Blu) ______________ I____________ 1 • I OPEN CIRCUIT LESS THAN 30 OHMS 1 VOLT/1 VOLT I Replace probe I I 505 circuit open Repair Check continuity from cavity D of probe harness to ground I 506 circuit open Repair _________ I_________ r NO C O NTINUITY 1 DAMAGED NORMAL I Repair connector I Replace module I Repair open in 503 circuit from probe to module 12 VOLTS/1 VO LT I -------------1 Replace relay C O NTINUITY I Remove module, check for deformed terminals in cavities C, G and H I------------------ 1-------------------NORMAL iFO R M ED I Repair the connector I Replace the module Fig. 6D-12D--C-10 Series Diesel Electrical System Diagnosis LIGHT TRUCK SERVICE MANUAL 12 VO LTS/2 VOLTS ENGINE ELECTRICAL 6D-29 GLOW PLUG RELAY BUZZING Disconnect the 12 w ay bulkhead connector. Check the continuity of the 503 circuit in the module connector to the glow plug relay. I 1 11 I 11 N O C O N T IN U IT Y C O N T IN U IT Y 503 circuit is open in the module jumper Repair as required Replace the module • GLOW PLUG RELAY NORMAL DON'T START/GLOW PLUGS LAMP DOES NOT LIGHT | I 1 C H EC K LAM P r 11 “I 1I GOOD BAD Check lamp ground continuity Replace lamp C O N T IN U IT Y N O C O N T IN U IT Y 503 circuit is open between lamp and 12 w ay bulkhead connector 150 circuit is open 11 11 Fig. 6D-13D--C-10 Series Diesel Electrical System Diagnosis LIGHT TRUCK SERVICE MANUAL 6D-30 ENGINE ELECTRICAL GLOW PLUG RELAY AND DON'T START/GLOW PLUGS LAMP ON AT COLD START, DOES NOT CYCLE AFTER INITIAL ON PERIOD (APPROX. 6 SECONDS AT 32°F) I Disconnect probe and check continuity between probe terminals C and D NO CONTINUITY Replace probe CONTINUITY I Measure the resistance between probe terminals C and E. MORE THAN 2 VOLTS MORE THAN 5 OHMS 0 VOLTS I I I (Measure the voltage at module connector cavity F. W ith ignition O N , measure the voltage at module connector cavity N Measure the voltage of the 25 circuit at the alternator r I LESS THAN 1 VOLT 12 VOLTS I I Turn ignition O F F , remove the module. Turn ignition O N , Check voltage at cavity F of the connector Check continuity of cavity D to ground of the probe harness connector. I Observe alternator lamp Brown wire from alternator to module open, repair as necessary. CONTINUITY I 12 VOLTS Turn ignition O F F . Remove the module. Check continuity from module connector cavity C to ground. I 505 circuit is shorted to batt. plus in the harness. Repair as necessary LAMP ON LAMP OFF I Bad alternator lamp or circuit 25 open from lamp to alternator Disconnect the tw o terminal connector from the alternator and check the voltage of the 25 circuit in the connector. r NO CONTINUITY J _________ L— ---------- I 0 VOLTS 12 VOLTS CONTINUITY I I I 25 circuit is shorted to ground in the harness. Repair short. Repair alternator 502 circuit is short to ground in the harness. Fig. 6D-14D--C-10 Series Diesel Electrical System Diagnosis LIGHT TRUCK SERVICE MANUAL I Replace the module NO CONTINUITY I 503 circuit is open between the probe and the glow plugs. Repair as necessary. ENGINE ELECTRICAL 6D-31 at m odule cavity L. 0 VOLTS I Turn ignition O F F . Rem ove the module. Check for con tinu ity to ground from m odule connector cavity L. LESS THAN 6 VOLTS 12 VOLTS Disconnect the^probe. Check voltage at cavity L o f the m odule connector. Disconnect the probe. Check the resistance , from probe term inals A to E. r J_______ I Turn ignition O F F . Rem ove the module. Turn ignition O N . Check voltage at m odule cavity L I. 501 circuit is shorted to ground in the harness. Repair as necessary 12 VOLTS 12 VOLTS I Turn Ignition off. Measure the resustance between these probe terminals is it: AtoE A to B Check cont. from M od. term L to probe term A 501 circuit is shorted to batt + in the harness 4 to 10 O H M S 10 to 20 O H M S 0 VOLTS Turn Ign. off. Reconnect the probe. Check resistance to ground from m odule connector cavity L NO Replace probe OPEN CONTINUITY I I Repair 501 circuit Replace M odule YES LESS THAN 20 OHM I \ Turn ignition O F F . Rem ove the module. Check con tinu ity to ground from m odule connector cavity J CONTINUITY Repair short to ground in 506 circuit harness I Replace the probe LESS THAN 20 OHMS I NO CO N TINU ITY CONTINUITY OPEN CIRCUIT OPEN CIRCUIT Replace the m odule 501 circuit is open in the harness NO CONTINUITY I Replace the module Fig. 6D-15D--C-10 Series Diesel Electrical System Diagnosis LIGHT TRUCK SERVICE MANUAL 6D-32 ENGINE ELECTRICAL JUNCTION BLOCK ASM ,W /S WIPER MOTOR ASM TEMP SENDER Engine I NOTE 1 For remainder of harness routing see sheet 12H-17. T A IL COMB LP EXT ASM BATTERY CABLE BRACE FW D LA M P HARNESS ASM SENDER OR SWITCH GENERATOR ASM &C60 /!°J GLOW PLUG VIEW C VIEW B TRANSMISSION ASM STARTER Engine ENGINE W IRING HARNESS ASM SOLENOID Engine FAST IDLE SOLENOID TEMP CONTROL SWITCH-Engine GLOW PLUG W IR IN G HARNESS ASM SOLENOID GENERATOR ASM exc C60 VIEW E Fig. 6D-16D--Engine Compartment Wiring LIGHT TRUCK SERVICE MANUAL ENGINE ELECTRICAL 6D-33 IGNITION SYSTEM - CONVENTIONAL ENGINES GENERAL DESCRIPTION CONTENTS General Description..............................................................6D-33 H .E.l. Distributor...............................................................6D-33 Ignition T im in g................................................................ ..6D-33 Secondary Wiring...............................................................6D-34 Spark Plugs........................................................................ ..6D-34 Ignition S w itch................................................................. ..6D-35 Diagnosis................................................. ............................. ..6D-35 H .E.l. Distributor...............................................................6D-35 On-Vehicle Service...............................................................6D-38 H.E.l. Distributor...............................................................6D-38 Remove and Replace.......................................................6D-39 Distributor..................................................................... 6D-39 Vacuum Advance U nit............................................... ...6D-39 Integral Ignition C o il................................................. ...6D-40 Module.............................................................................. 6D-41 Pick-up C oil..................................................................... 6D-41 Set Ignition Tim ing............................................................ 6D-43 Spark Plug W ires............................................................... 6D-43 GENERAL DESCRIPTION The ignition circuit consists of the battery, the distrib­ utor, the ignition switch, the spark plugs, and the primary and secondary wiring. Refer to the Battery portion of this section for battery information. also features a longer spark duration, made possible by the higher amount of energy stored in the coil primary. This is desirable for firing lean mixtures. H.E.l. DISTRIBUTOR When making compression checks, disconnect ignition switch connector (pink wire) from HEI system. No periodic lubrication is required. Engine oil lubrica .es the lower bushing and an oil-filled reservoir provides lubrication for the upper bushing. The High Energy Ignition distributor used on all engines combines all ignition components in one unit (Fig. 6D -17D and 6D-18D). The external electrical connections are the ignition switch feed wire, the tachometer pickup, and the four, six or eight spark plug leads. The ignition switch feed connector to the distributor has full battery voltage when the ignition switch is in the "R U N " and "START" positions. There is NO RESISTOR W IRE FROM THE IG N IT IO N SW ITCH TO TH E D IST R IB U T O R . The ignition coil is in the distributor cap and connects through a resistance brush to the rotor. The High Energy Ignition System is basically identical in operation to conventional ignition except the module and pick-up coil replace the contact points. The High Energy Ignition is a magnetic pulse trig­ gered, transistor controlled, inductive discharge ignition system. The magnetic pick-up assembly located inside the distributor contains a permanent magnet, a pole piece with internal teeth, and a pick-up coil. When the teeth of the timer core rotating inside the pole piece line up with the teeth of the pole piece, an induced voltage in the pick-up coil signals the electronic module to trigger the coil primary circuit. The primary current decreases and a high voltage is induced in the ignition coil secondary winding which is directed through the rotor and secondary leads to fire the spark plugs. The capacitor in the distributor is for radio noise supression. The magnetic pick-up assembly is mounted over the main bearing on the distributor housing, and is made to rotate by the vacuum control unit, thus providing vacuum advance. The timer core is made to rotate about the shaft by conventional advance weights, thus providing centrifugal advance. The module automatically controls the dwell period, stretching it with increasing engine speed. The HEI system IGNITION TIMING Timing specifications for each engine are Section 6E and on the Vehicle Emissions Control tion label on the radiator support. When using light, connect an adapter between the No. 1 spark GROUND TERMINAL listed in Informa­ a timing plug and BAT. TERMINAL (CONNECTED TO IGNITION SWITCH) / LATCH (4) CONNECT TACHOMETER FROM THIS TERMINAL TO GROUND. TACH TERMINAL CONNECTOR C-TERMINAL (SOME TACHOMETERS MUST CONNECT FROM THIS TERMINAL TO ENERGIZER POSITIVE ( + ). CONSULT TACHOMETER MANUFACTURER.) Fig. 6D-17D-HEI Distributor Assembly LIGHT TRUCK SERVICE MANUAL 6D-34 ENGINE ELECTRICAL o . * Fig. 6 D -1 9 D --S p a rk Plug - T apered Seat SPARK PLUGS (FIG. 6D-19D) Fig. 6 D -1 8 D --H E I Distributor - E xp loded View the No. 1 spark plug wire, or use an inductive type pick-up. Do not pierce the plug lead. Once the insulation of the spark plug cable has been broken, voltage will jump to the nearest ground, and the spark plug will not fire properly. The timing procedure remains the same as the conventional ignition system. Always follow Vehicle Emissions Control Informa­ tion label procedures when adjusting timing. Some engines will incorporate a magnetic timing probe hole for use with special electronic timing equipment. Consult m anufacturer’s instructions for use of this equipment. SECONDARY WIRING The spark plug wiring used with the HEI system is a carbon impregnated cord conductor encased in an 8mm diameter silicone rubber jacket. The silicone wiring will withstand very high temperatures and also provides an excellent insulator for the higher voltage of the HEI system. The silicone spark plug boots form a tight seal on the plug and the boot should be twisted 1/2 turn before removing. Care should also be exercised when connecting a timing light or other pick-up equipment. Do not force contacts between the boot and wiring or through the silicone jacket. Connections should be made in parallel using an adapter. DO NOT pull on the wire to remove. Pull on the boot, or use a tool designed for this purpose. LIGHT TRUCK SERVICE MANUAL Resistor type, tapered seat spark plugs are used on all gasoline engines. No gasket is used on these tapered seat plugs. See Fig. 6D-20D for an explanation of letter coding on spark plugs. See Engine Exhaust Emissions Section (6E) for spark plug application and gap sizes. Always replace plugs with the correct plug listed on the tune-up label. Normal or average service is assumed to be a mixture of idling, slow speed, and high speed operation with some of each making up the daily total driving. Occasional or intermittent high-speed driving is essential to good spark plug performance as it provides increased and sustained combustion heat that burns away any excess deposits of carbon or oxide that may have accumulated from frequent idling or continual stop-and-go or slow-speed driving. Spark plugs are protected by an insulating nipple made of special heat-resistant material which covers the spark plug terminal and extends downward over a portion of the plug insulator. These nipples prevent flash-over with resultant missing of engine, even though a film is allowed to accumulate on exposed portion of plug porcelains. Do not mistake corona discharge for flash-over or a shorted insulator. Corona is a steady blue light appearing around insulator, just above the shell crimp. It is the visible evidence of high-tension field, and has no effect on ignition performance. Usually it can be detected only in darkness. This discharge may repel dust particles, leaving a clear ring on the insulator just above the shell. This ring is sometimes mistakenly regarded as evidence that combustion gases have blown out between shell and insulator. ENGINE ELECTRICAL 6D-35 IGNITION SWITCH 1 2 3 R T V 1 2 3 4 - 5 - 4 T 5 The m echanical switch is located in the steering column on the right hand side just below the steering wheel. The electrical switching portion of the assembly is separate from the key and lock cylinder. However, both are synchro­ nized and work in conjunction with each other through the action of the actuator rod assembly. S X~ R--INDICATES RESISTOR-TYPE PLUG. "4 " INDICATES 14 mm THREADS. HEAT RANGE TS-TAPERED SEAT. S -E X T E N D E D T IP SPECIAL GAP 6221 Fig. 6D-20D--Spark Plug Coding For a complete explanation of the key and lock cylinder, and the actuator rod assembly, see S T E E R I N G , Section 3B. See Section 8 for the detailed explanation of the electrical switching. DIAGNOSIS H.E.I. DISTRIBUTOR Use Figure 6D-21D and 22D for H.E.I. Diagnosis. SPARK PLUGS Worn or dirty plugs may give satisfactory operation at idling speed, but under operating conditions they frequently fail. Faulty plugs are indicated in a number of ways: poor fuel economy, power loss, loss of speed, hard starting and general poor engine performance. Spark plug failure, in addition to normal wear, may be due to carbon fouled plugs, excessive gap or broken insulator. Fouled plugs may be indicated by checking for black carbon deposits. The black deposits are usually the result of slow-speed driving and short runs where sufficient engine operating temperature is seldom reached. Worn pistons, rings, faulty ignition, over-rich carburetion and spark plugs which are too cold will also result in carbon deposits. Excessive gap wear, on plugs of low mileage, usually indicates the engine is operating at high speeds or loads that are consistently greater than normal or that a plug which is too hot is being used. In addition, electrode wear may be the result of plug overheating, caused by combustion gases leaking past the threads, due to insufficient torquing of the spark plug. Excessively lean carburetion will also result in excessive electrode wear. Broken insulators are usually the result of improper installation or carelessness when regapping the plug. Broken upper insulators usually result from a poor fitting wrench or an outside blow. The cracked insulator may not make itself evident immediately, but will as soon as oil or moisture penetrates the fracture. The fracture is usually just below the crimped part of shell and may not be visible. Broken lower insulators usually result from careless­ ness when regapping and generally are visible. In fairly rare instances, this type of break may result from the plug operating too " h o t" , encountered in sustained periods of high-speed operation or under extremely heavy loads. When regapping a spark plug, to avoid lower insulator breakage, always make the gap adjustment by bending the ground (side) electrode. Spark plugs with broken insulators should always be replaced. LIGHT TRUCK SERVICE MANUAL 6D-36 ENGINE ELECTRICAL ENGINE CRANKS, BUT WILL NOT START NOTE: IF A TACHOMETER IS CONNECTED TO THE TACHOMETER TERM INAL, DISCONNECT IT BEFORE PROCEEDING WITH THE TEST. NOTE: VIEWS ARE IN PART 2. Fig. 6D -21D --H EI Diagnosis LIGHT TRUCK SERVICE MANUAL 6741 ENGINE ELECTRICAL 6D-37 IN T E R M IT T E N T OPERATION OR MISS REM O VE GREEN AN D W H ITE LEADS FRO M M O DULE C35 0 CUT A SPARK PLUG BOOT AS SHOWN (TO BAT +) TEST LIG H T DISCARD CONNECT V O LT M E T E R , "T A C H " T E R M IN A L TO G RO UND 7 /1 6 " (11mm) FROM TIP OF SPARK PLUG VIEW B INSERT BOOT OVER PORCELAIN END OF ST-125 6742 Fig. 6D -22D --H E I Diagnosis LIGHT TRUCK SERVICE MANUAL 6D-38 ENGINE ELECTRICAL DETACH LEADS FROM MODULE OHMMETER OHMMETER Fig. 6D-24D--Checking Pickup Coil Fig. 6D-23D~Checking Internal Coil ON-VEHICLE SERVICE H.E.I. DISTRIBUTOR Service Precautions 1. W hen making compression checks, disconnect the ignition switch feed wire at the distributor. W hen disconnecting this connector do not use a screwdriver or tool to release the locking tab as it may break. 2. No periodic lubrication is required. Engine oil lubri­ cates the lower bushing and an oil-filled reservoir provides lubrication for the upper bushing. 3. The tach om eter (T A C H ) term inal is next to the ignition switch (BAT) connector on the distributor cap. NOTICE: The tachometer terminal must N E V E R be allowed to touch ground, as damage to the module and/ or ignition coil can result.. LIGHT TRUCK SERVICE MANUAL Some service tachometers and electronic diagnostic equipment currently in use may N O T be compatible with the High Energy Ignition System. It is recom­ mended that you consult your representative of such equipment as to the necessary updating of your equip­ ment for compatibility with the HEI System. 4. There is no dwell adjustment as this is controlled by the module. 5. The centrifugal advance and vacuum advance are similar to the conventional ignition. 6. The material used to construct the spark plug cables is very pliable and soft. This cable will withstand more heat and carry a higher voltage. Due to the more pliable cable, scuffing and cutting become easier. It is therefore extremely important that the spark plug cables be routed correctly to prevent chaffing or cutting. See ENGINE ELECTRICAL 6D-39 Fig. 6 D -25 D -D istrib utor Base and Components Spark Plug Section of On-Vehicle Service. Also when removing a spark plug wire from a spark plug, twist the boot on the spark plug and pull on the boot to remove the wire. Remove and Replace Fig. 6D-25D shows a new type connector for the module and capacitor. There are no changes to either diagnosis or circuitry. Distributor 1. Disconnect ignition switch b attery feed wire and tachometer lead (if equipped) from distributor cap. Also release the coil connectors from the cap. (DO N O T use a screwdriver or tool to release the locking tabs.) 2. Remove distributor cap by turning four latches coun­ terclockwise. Move cap out of the way. If necessary to remove secondary wires from cap, release wiring harness latches and remove wiring harness retainer. The spark plug wire numbers are indicated on the retainer. 3. Remove vacuum hose from vacuum advance unit. 4. Remove distributor clamp screw and hold-down clamp. 5. Note position of rotor, then pull distributor up until rotor just stops turning counterclockwise and again note position of rotor. NOTICE: To insure correct timing of the distributor, the distributor must be IN S T A L L E D with the rotor correctly positioned as noted in Step 5. If the engine was accidentally cranked after the distributor was removed, the following procedure can be used for installing: a. Remove No. 1 spark plug. b. Place finger over No. 1 spark plug hole and crank engine slowly until compression is felt. c. Align timing m ark on pulley to " O " on engine timing indicator. d .T u rn rotor to point between No. 1 and No. 8 spark plug towers on distributor cap. e. Install distributor and connect ignition feed wire. f. Install distributor cap and spark plug wires. g. Check engine timing (see Set Ignition Timing below). Vacuum Advance Unit (Refer to Fig. 6D-25D) REMOVAL 1. 2. 3. 4. Remove distributor cap and rotor. Remove module. Remove two vacuum advance attaching screws. Turn the pick-up coil clockwise and push the rod end of the vacuum advance down so that it will disengage and clear the pick-up coil plate. INSTALLATION To install, reverse removal procedure. LIGHT TRUCK SERVICE MANUAL 6D-40 ENGINE ELECTRICAL UNIT REPAIR DISTRIBUTOR DISASSEMBLY TEST AND REASSEMBLY (COIL IN CAP) TESTING IGNITION COIL "COIL IN C A P ” D ISTRI BUTOR COIL AND CAP TER MINA LS B+ ASSEMBLY OHMMETER 4 -TE RM IN AL CONNECTOR CONNECTOR (DISCONNECTED FROM CAP) OHMMETER 4. Connect ohmmeter, Test 1. 5. Reading should be zero, or nearly zero. If not, replace coil, Step 8. 6. Connect ohmmeter both ways, Test 2. Use high scale. Replace coil only if both readings are infinite. Step 8. 7. If coil is good, go to Step 13. IGNITION COIL ATTACHING SCREWS COIL A T T A C H I N G ^ ^ ^ _ asBa^ ^ SCREW (4) IG NITIO N / COIL 1. A 6-cyl. EST distributor with coil-in-cap is illustrated. 2. Detach wiring connector from cap, as shown. 3. Turn four latches and remove cap and coil assembly from lower housing. GROUND LEAD COIL SECONDARY C- GRD. B+ T ER MINA LS 8. Remove coil-cover attaching screws and lift off cover. Fig. 6D-26D--Distributor Unit Repair LIGHT TRUCK SERVICE MANUAL ENGINE ELECTRICAL IGNITION COIL REMOV ED FROM CAP SEAL GROUND 6D-41 D RI VI NG PIN FROM S HA F T IG NITIO N COIL CONNECTOR 9. Remove ignition coil attaching screws and lift coil with leads from cap. 10. Remove ignition coil arc seal. 11. Clean with soft cloth and inspect cap for defects. Re­ place, if needed. 12. Assemble new coil and cover to cap. 18. Mark distributor shaft and gear so they can be reassem­ bled in same position. TESTING PICKUP COIL 19. Drive out roll pin. OHMMETER OHMMETER PICKUP COIL LEADS DISCONNECTED FROM MODULE 4-T E R M IN A L CONNECTOR S HA F T A S S E M B LY REMOV ED THREE ATTA CH IN G SCREWS M AGNETIC IELD MODULE PICKUP COIL ASSEMBLY T E R M IN A L 13. On all distributors, remove rotor and pickup coil leads from module. 14. Connect ohmmeter Test 1 and then Test 2. 15. If vacuum unit is used, connect vacuum source to vac­ uum unit. Replace unit if inoperative. Observe ohmmeter throughout vacuum range; flex leads by hand without vacuum to check for intermittent opens. 16. Test 1 — should read infinite at all times. Test 2 — should read steady at one value within 500-1500 ohm range. NOTE: Ohmmeter may deflect if operating vacuum unit causes teeth to align. This is not a defect. 17. If pickup coil is defective, go to Step 18. If okay, go to Step 23. PICKUP COIL LEADS DIS­ CONNECTED FROM MODULE 20. Remove gear and pull shaft assembly from distributor. Fig. 6D -27D ~D istributor Unit Repair LIGHT TRUCK SERVICE MANUAL 6D-42 ENGINE ELECTRICAL PICKUP COIL PICKUP COIL LEADS DIS­ CONNECTED MODULE 23. Remove two module attaching screws, and capacitor at­ taching screw. Lift module, capacitor and harness assembly from base. 24. Disconnect wiring harness from module. 21. Remove three attaching screws and remove magnetic 25. Check module with an approved module tester. shield. 26. Install module, wiring harness, and capacitor assembly. Use silicone lubricant on housing under module. I NSTALL PICKUP COIL, S H A F T A SS EM BLY A N D CAP 27. Install pickup coil assembly, shaft and gear. 28. Spin shaft and if used, operate the vacuum unit to insure that teeth do not touch. PICKUP COIL REMOV ED A N D DISASSEMBLED To eliminate contact, loosen three pickup screws, then re* tighten and check for contact. 29. Assemble rotor, cap assembly and attach wiring harness to cap. 22. Remove retaining ring and remove pickup coil, magnet and pole piece. Fig. 6D-28D--Distributor Unit Repair LIGHT TRUCK SERVICE MANUAL ENGINE ELECTRICAL 6D-43 SET IGNITION TIMING 1. Refer to the Vehicle Emissions Control Information label located on the radiator support panel. Follow all instructions on the label. 2. With ignition off, connect the pick-up lead of timing light to the number one spark plug. Use a jumper lead between the wire and plug or an inductive type pick-up. DO N O T pierce the wire or attempt to insert a wire between the boot and the wire. Connect the timing light power leads according to m anufacturer’s instructions. 3. Start the engine, and aim the timing light at the timing mark (see Fig. 6D-29D). The line on the balancer or pulley will line up at the timing mark. If a change is necessary, loosen the distributor hold-down clamp bolt at the base of the distributor. While observing the mark with the timing light, slightly rotate the distributor until the line indicates the correct timing. Tighten the hold-down bolt, and re-check the timing. 4. T urn off the engine and remove the timing light. Reconnect the number one spark plug wire, if removed. SPARK PLUG WIRES Use care when removing spark plug wire boots from spark plugs. Twist the boot 1/2 turn before removing, and pull on the boot only to remove the wire. It is extremely important when replacing plug wires to route the wires correctly and through the proper retainers. Failure to route the wires properly can lead to radio ignition noise and crossfiring of the plugs, or shorting of the leads to ground. Refer to Figure 6D-30D for proper spark plug wire routing. LIGHT TRUCK SERVICE MANUAL 6 D -4 4 E N G IN E ELECTRICAL C Y L #1 _^CYL #2 Sfer CYL #7 j P ' ^ ' C Y L #5 F I L T E R ASM r~POWER U N IT F I L T E R ASM V IE W -A POWER U N I T CYL #1 CYL^#3 CYL #5 LEFT SIDE W ITH CRUISE CONT. R IG H T SIDE V IE W -A V IE W Fig. 6 D -30 D --S p ark Plug W ire Routing LIGHT TRUCK SERVICE MANUAL ENGINE ELECTRICAL 6D-45 IGNITION SWITCH GENERAL DESCRIPTION The electrical switching portion of the assembly is separate from the key and lock cylinder. However, both are synchronized and work in conjunction with each other through the action of the actuator rod assembly. For a complete explanation of the key and lock cylinder, and the actuator rod assembly, refer to the Steering section of this manual. The ignition switch is key operated through the actua­ tor rod assembly to close the ignition primary circuit and to energize the starting motor solenoid for cranking. The ignition switch used on all cars have five positions: OFF, LOCK, A C C E S S O R Y , R U N and ST A R T . O F F is the center position of the key-lock cylinder, and LOCK is the next position to the left. A C C E S S O R Y is located one more detent to the left of LOCK. Turning the key to the right of the O F F position until spring pressure is felt will put the ignition switch in the R U N position, and when turned fully to the right against spring pressure, the switch will be in the S T A R T position. All ignition switches have five terminals which are connected in different combinations for each of the three operating positions. A brass plate, inside the switch, has three contacts which connect these terminals. Figure 6D31D shows the positions of the contacts in all positions as viewed from the key side of the switch. There is also a ground pin in the switch which contacts the "ground" terminal when the ignition switch is in the S T A R T position. This pin contacts the IG N. terminal when in the O F F position. terminal is connected to the ACC. terminal. This permits operation of accessories when the engine is not running. When the ignition switch is turned to the S T A R T position, the BAT. terminal is connected to the SOL. and IGN. terminals. When the clutch or automatic transmission neutral start switches are closed, current flows to the starter solenoid. This energizes the solenoid windings. The solenoid has two sets of windings: a "pull-in" winding and a "holdin" winding. Both windings are used to create the magnetic field to actuate the the solenoid plunger and move the starter pinion into engagement with the flywheel. As the solenoid plunger reaches the end of its travel, it closes a switch which connects battery voltage to the starter motor. With battery voltage applied to both terminals of the "pull-in" windings, the "pull-in" winding is no longer energized, so that only the "hold-in" winding keeps the starter solenoid engaged. The instrument panel warning lights are fed from the ignition terminal of the ignition switch and have battery voltage applied to them when the ignition switch is in the S T A R T and R U N position. These circuits are explained in the Chassis Electrical Section. When the ignition switch is released from the S T A R T to the RU N position, the IGN. terminal is still connected to the BAT. terminal With the ignition switch in the RU N position, the BAT. term inal is connected to the IG N . terminal and the ACC. terminal. This permits operation of all accessories and the ignition system. Ignition S tart a n d Run Circuit The ignition switch is fed from the battery to the BAT. terminal of the switch. When the ignition switch is in the O F F position, no current flows through the switch. When the ignition switch is turned to the ACC. position, the BAT. ENGINE WIRING HARNESSES Engine Wiring Harnesses are shown in Figures 6D32D through 6D-37D. LIGHT TRUCK SERVICE MANUAL 6D-46 ENGINE ELECTRICAL 12 R 12P P L / W r\ I SOL 1 5 L BAT 2 1 BAT 1 C 2 » I 12 ORN ■ IGN 1 --------- 12 P 24 B R N / W 1 J 12 B R N _GRD-1 20 D G |0 » D -2 l.g ^ 3 | IG N ITIO N SWITCH (VIEW FROM TERMINAL POSITIONS— SIDE OF SWITCH) OFF POSITION ACC IGN-3 IGN-3 □ BAT-3 so l L D . BAT-1 J fORD-2\ LOCK POSITION ACC IGN-3 SOL Q BAT-2 UIGNU RUN POSITION Fig. 6D-31 D--lgnition Switch Circuit LIGHT TRUCK SERVICE MANUAL I/P HARN A .I.R . ELBOW Fig. 6D -32D --Engine Wiring CK-LE9, LF3, LG9, LS9 H .E .I DISTRIBUTOR Engine GRD ENGINE WIRE ASM TO H .E .I. ENGINE DISTR WIRE ASM E.S.C. CONNECTOR ENGINE HARNESS ELECTRICAL 6 D -4 7 6D-48 ENGINE ELECTRICAL Fig. 6 D -3 3 D --E n g in e W irin g C K -2 0 , 3 0 - LE8 LIGHT TRUCK SERVICE MANUAL CHEVROLET LIGHT TRUCK Fig. 6D -34D --Engine Wiring C K -20, 30 - LT9, LF5 ENGINE © SO M E O C C ASIO N AL TRACE-TO-LIGHT DETO NATIO N IS AC C EPTAB LE. 6 D -4 9 TH IS DIAG NO SIS SHOULD BE INSERTED W ITH OR IM M E D IA TE LY AFTER ITEM a. (FAULTY IGNITION SYSTEM ) OF THE “ ENGINE DETO NATIO N” SECTION ON PAGE 6A-7 OF THE 1980 LIGHT D U TY T R U C K SERVICE MANUAL ELECTRICAL © 6D-50 ENGINE CHEVROLET LIGHT TRUCK ESC SYSTEM DIAGNOSIS ELECTRICAL Fig. 6D-35D --Engine Wiring G Series LE3 © T H IS DIAG NO SIS SHO ULD BE INSERTED IM M EDIATELY AFTER ITEM b. (IGNITION TIM IN G ) OF THE “ ENGINE HAS LO W PO W ER ” SECTION ON PAGE 6A-3 OF THE 1980 LIG HT DUTY TRUCK SERVICE M ANUAL. CHEVROLET LIGHT TRUCK ESC SYSTEM DIAGNOSIS Fig. 6D-36D--Engine Wiring CK Series - LE3, L25 ENGINE ELECTRICAL © T H IS DIAG NO SIS SHO ULD BE INSERTED WITH OR IM M E D IA TE LY AFTER ITEM g. (IGNITION P R O B LE M S ) OF THE “ ENG INE FAILS TO START” SECTION ON PAGE 6A-2 OF THE 1980 LIG HT D U TY T R U C K SERVICE M ANU AL. 6D -51 6D-52 ENGINE ELECTRICAL K J H G F E ESC CO NTROLLER D C B - A GRND DELAY LO HI BAT. BROWN BLACK WHITE GREEN PINK/BLK SENSOR SHIELD PINK > C > B > BROWN > BLACK > A > D > GREEN > WHITE BROWN BLACK WHITE GREEN Fig. 6D-37D--Engine W iring CK Series - LE9 LIGHT TRUCK SERVICE MANUAL ENGINE ELECTRICAL 6D-53 CRANKING SYSTEM General Description.............................................................6D-53 Cranking C i r c u i t...............................................................6D-53 Starter M o t o r ................................................................... .6D-53 Diagnosis............................................................................... .6D-56 On-Vehicle Service............................................................ .6D-60 Remove and Replace........................................................6D-60 S ta r te r ................................ .............................................. .6D-60 Solen oid............................................................................ 6D-60 O v e rh a u l............................................................................... 6D-61 Disassembly....................................................................... 6D-61 Component Inspection..................................................... 6D-62 Reassembly.......... ................................................... .......... 6D-64 Specifications....................................................................... 6D-67 GENERAL DESCRIPTION CRANKING CIRCUIT The cranking circuit consists of the battery, staring motor, ignition switch, and related electrical wiring. These components are connected electrically as shown in Figure 6D-1E. Only the starting motor will be covered in this portion. STARTING MOTOR Two types of starter motors are used. The first, referred to as the 10MT series, is shown in Fig. 6D-2E. The second type, referred to as the 20MT series used on diesel equipped engines, is shown in Fig. 6D-3E. The main difference is that the 2 0 M T has a center bearing. Fig. 6D -4E shows an exploded view of the 20M T series. Differences in service procedures will be pointed out as they occur. Enclosed shift lever cranking motors have the shift lever mechanism and the solenoid plunger enclosed in the drive housing protecting them from exposure to dirt, icing conditions and splash. In the basic circuit shown in Figure 6D-1E, the solenoid windings are energized when the switch is closed. The resulting plunger and shift lever movement causes the pinion to engage the engine flywheel ring gear and the solenoid main contacts to close, and cranking takes place. When the engine starts, pinion overrun protects the arm ature from excessive speed until the switch is opened, at which time the return spring causes the pinion to disengage. To prevent excessive overrun, the switch should be opened immediately when the engine starts. LIGHT TRUCK SERVICE MANUAL 6D-54 ENGINE ELECTRICAL Fig. 6D-1 E--Cranking Circuit - A ll SOLENOID SWITCH TERMINAL PLUNGER RETURN SPRING SHIFT LEVER BUSHING PINION STOP INSULATED BRUSH HOLDER BRUSH RISER BARS TO RISER BARS TO ARMATURE Fig. 6D-2E--Cross Section of 10M T Starting M o to r LIGHT TRUCK SERVICE MANUAL OVERRUNNING CLUTCH ENGINE ELECTRICAL SOLENOID SWITCH TERMINAL PLUNGER 6D-55 RETURN SPRING SHIFT LEVER BUSHING PINION STOP INSULATED BRUSH HOLDER BRUSH RISER BARS CONDUCTORS TO RISER BARS TO ARMATURE OVERRUNNING CLUTCH Fig. 6D-3E~Cross Section of 20MT Starting M otor LIGHT TRUCK SERVICE WANII4I 6D-56 ENGINE ELECTRICAL PLUNGER D R IV E GEAR HOUSING RETURN SPRING SO LENOID COM M UTATO R END FRAME T U P I I QT WASHER RETA IN ER SNAP RING FIBER WASHER F IE LD FRAME WASHER CLUTCH AND D R IV E ASM. CENTER BEARING AR M A TU R E Fig. 6D-4E~Exploded View of 20MT Starting M otor DIAGNOSIS Before removing any unit in a cranking circuit for repair, the following checks should be mad?: Battery: To determine the condition of the battery, follow the testing procedure outlined in the Battery Section. W iring: Inspect the wiring for damage. Inspect all connections to the cranking motor, solenoid, ignition switch, and battery, including all ground connections. Clean and tighten all connections as required. Solenoid a n d Ignition Switch: Inspect all switches to determine their condition. Starter M otor Noise: To correct starter motor noise during starting, use the following procedure: 1. Refer to Fig. 6D-5E to determine the problem. 2. If the complaint is smiliar to problem categories 1 or 2 above, correction can be achieved by proper "shim­ ming" as follows: a. Remove lower flywheel housing cover and examine for visual proelbmes - bent flywheel, unusual wear, etc. b. Start engine and carefully touch outside diameter of rotating flywheel ring gear with chalk or crayon to show high point of tooth runout after engine is turned off. Turn engine off and rotate flywheel so that the marked teeth are in the area of the starter pinion gear. c. Disconnect negative battery cable to prevent inad­ vertent cranking of engine. Insert screwdriver in small hole in bottom of starter shown by arrow in Fig. 6D-6E and move starter pinion and clutch assembly so that pinion teeth and flywheel teeth are meshed. If necessary, rotate the flywheel so that a pinion tooth is directly in the center of two flywheel teeth and on the centerline of the two gears, as shown in Fig. 6D-7E. ENGINE ELECTRICAL PROBLEM 6D-57 CAUSE 1. HIGH PITCHED WHINE DURING CRANKING (BEFORE ENGINE FIRES) BUT ENGINE CRANKS AND FIRES OKAY. DISTANCE TOO GREAT BETWEEN STARTER PINION AND FLYWHEEL. 2. HIGH PITCHED "W HINE" AFTER ENGINE FIRES, AS KEY IS BEING RELEASED. ENGINE CRANKS AND FIRES OKAY. THIS INTERMITTENT COMPLAINT IS OFTEN DIAGNOSED AS "STARTER HANG-IN" OR "SOLENOID WEAK." DISTANCE TOO SMALL BETWEEN STARTER PINION AND FLYWHEEL. FLYWHEEL RUNOUT CONTRIBUTES TO THE INTERMITTENT NATURE. 3. A LOUD "WHOOP" AFTER THE ENGINE FIRES BUT WHILE THE STARTER IS STILL HELD ENGAGED. SOUNDS LIKE A SIREN IF THE ENGINE IS REVVED WHILE STARTER IS ENGAGED. MOST PROBABLE CAUSE IS A DEFECTIVE CLUTCH. A NEW CLUTCH WILL OFTEN CORRECT THIS PROBLEM. 4. A "RUM BLE", "GROW L" OR (IN SEVERE CASES) A "KNO C K" AS THE STARTER IS COASTING DOWN TO A STOP AFTER STARTING THE ENGINE. MOST PROBABLE CAUSE IS A BENT OR UNBALANCED STARTER ARMATURE. A NEW ARMATURE WILL OFTEN CORRECT THIS PROBLEM. r/lon 5488 Fig. 6 D-5E--Starter M o to r Noise Diagnosis Fig. 6D -6E -M eshin g Starter and Flywheel Teeth d. Check pinion to flywheel clearance, as shown in Fig. 6D-50, by using a wire gage of .20" m inim um thickness (or diameter). If the clearance is under this minimum, shimm ing the sta rte r away from the flywheel is required. Shim (P art # 9 7 8 5 6 0 8 or equivalent, .015" thick), installed as shown in Fig. 6D-8E, will increase the clearance by approximately .005 ". More than one shim may be required. It is very important to center the pinion tooth between the flywheel teeth and gage, as shown in Fig. 6D-50, and not in the corners, where a misleading larger dimension may be observed. NOTICE: e. If the clearance is grossly over .020" (in the vacinity of .060" or more), shimming the starter towards the flywheel is required. (This is generally the problem causing broken flywheel teeth or starter housings.) Shimming the starter towards the flywheel can be accomplished by shimming only the outboard starter mounting pad. A shim of .015" thickness, P art # 1 2 4 6 2 4 9 or equivalent, at this location will de­ crease the clearance by approximately .010". Substitu te shims can be improvised from plain washers or other suitable material. 3. Problem categories 3 and 4 above may require starter motor replacement or repair in some cases. LIGHT TRUCK SERVICE MANUAL 6D-58 ENGINE ELECTRICAL V8 ENGINE SHIELD BRACE LF9 ENGINE STARTER MOTOR Fig. 6D-8E--Starter M o to r Mounting LIGHT TRUCK SERVICE MANUAL ENGINE ELECTRICAL Motor: If the battery, wiring and switches are in satisfactory condition, and the engine is known to be functioning properly, remove the motor and follow the test procedures outlined below. Regardless of the construction, never operate the cranking motor more than 30 seconds at a time without pausing to allow it to cool for at least two minutes. Overheating, caused by excessive cranking, will seriously damage the cranking motor. A general diagnosis is covered in Figure 6D-2A and 6D-3A. Once a problem has been traced to the starter, proceed to the test procedure below. Test Procedure With the cranking motor removed from the engine, the pinion should be checked for freedom of operation by turning it on the screw shaft. The arm ature should be checked for freedom of rotation by prying the pinion with a screwdriver. Tight bearings, a bent arm ature shaft, or a loose pole shoe screw will cause the arm ature to not turn freely. If the armature does not turn freely the motor should be disassembled immediately. However, if the armature does rotate freely, the motor should be given a no-load test before disassembly. No-Load Test (Fig. 6D-9E) Connect a voltmeter from the motor terminal to the motor frame, and use an R P M indicator to m easure arm ature speed. Connect the motor and an ammeter in series with a fully charged battery of the specified voltage, and a switch in the open position from the solenoid battery terminal to the solenoid switch terminal. Close the switch and compare the RPM, current, and voltage readings with the specifications at the end of this section. It is not necessary to obtain the exact voltage specified in the figure, as an accurate interpretation can be made by recognizing th a t if the voltage is slightly higher the R P M will be proportionately higher, with the current remaining essen­ tially unchanged. However, if the exact voltage is desired, a 6D-59 carbon pile connected across the battery can be used to reduce the voltage to the specified value. If the specified current draw does not include the solenoid, deduct from the ammeter reading the specified current draw of the solenoid hold-in winding. Make disconnections only with the switch open. Interpret the test results as follows: 1. Rated current draw and no-load speed indicates normal condition of the cranking motor. 2. Low free speed and high current draw indicates: a. Too much friction - tight, dirty, or worn bearings, bent arm ature shaft or loose pole shoes allowing arm ature to drag. b. Shorted armature. This can be further checked on a growler after disassembly. c. Grounded arm ature or fields. Check further after disassembly. 3. Failure to operate with high current draw indicates: a. A direct ground in the terminal or fields. b. "Frozen" bearings (this should have been deter­ mined by turning the arm ature by hand). 4. Failure to operate with no current draw indicates. a. Open field circuit. This can be checked after disas­ sembly by inspecting internal connections and trac­ ing circuit with a test lamp. b. Open arm ature coils. Inspect the commutator for badly burned bars after disassembly. c. Broken brush springs, worn brushes, high isulation between the commutator bars or other causes which would prevent good contact between the brushes and commutator. 5. Low no-load speed and low current draw indicates: a. High internal resistance due to poor connections, defective leads, dirty commutator and causes listed under N um ber 4. 6. High free speed and high current draw usually indicate shorted fields. If shorted fields are suspected, replace the field coil assembly and check for improved perform­ ance. In some instances, the arm ature could also be shorted. Check on a growler. LIGHT TRUCK SERVICE MANUAL 6D-60 ENGINE ELECTRICAL S" TERMINAL SOLENOID GROUND 1 2-VOLT BATTERY Fig. 6D-9E--No Load Test Hook Up ON-VEHICLE SERVICE Starting motors do not require lubrication except during overhaul. W hen the motor is disassembled for any reason, lubricate as follows: 1. The arm ature shaft and drive end and commutator end bushings should be coated with no. 1960954 lubricant or equivalent. 2. The roll type overrunning clutch requires no lubrica­ tion. However, the drive assembly should be wiped clean. Do not clean in any degreasing tank or with grease dissolving solvents; this will dissolve the lubri­ cant in the clutch mechanism. Use silicon grease General Electric CG321, Dow Corning 33 Medium or equivalent, on the shaft underneath the overrunning clutch assembly. REMOVE AND REPLACE Starter (Fig. 6D-8E) Use the following procedure to remove the starter: LIGHT TRUCK SERVICE MANUAL 1. Disconnect negative battery lead at battery. 2. Raise vehicle. 3. Remove starter braces, shields, etc., that may be in the way. 4. Remove two starter motor to engine bolts, and allow starter to drop down. 5. Remove solenoid wires and battery cable and remove starter. 6. To replace, reverse the above procedure. Insure that any shims removed are replaced. Solenoid Use the following procedure to remove the solenoid from the starter: 1. Disconnect field strap. 2. Remove solenoid to drive housing attaching screws, motor terminal bolt, and remove solenoid by twisting. 3. Replace by reversing above procedures. ENGINE ELECTRICAL 6D-61 UNIT REPAIR 5MT, 10MT, 25MT AND 27MT STARTER MOTORS DISASSEMBLY, TEST AND REASSEMBLY (STARTER REMOVED FROM ENGINE) NO- LOA D TEST With the starter motor removed from the engine, the pinion should be checked for freedom of operation by turning it on the screw shaft. The armature should be checked for freedom of rotation by prying the pinion with a screwdriver. If the armature does not turn freely, the motor should be disassembled im­ mediately. However, if the armature does rotate freely, the motor should be given a no-load test before disassembly. Make connections as shown. Close the switch and compare the RPM, current, and voltage readings with the specifications . If the specified current draw does not include the solenoid, deduct from the ammeter reading the specified current draw of the solenoid hold-in winding. Make disconnec­ tions only with the switch open. Use the test results as follows: 1. Rated current draw and no-load speed indicates normal condition of the starter motor. 2. Low free speed and high current draw indicates: • Too much friction — tight, dirty, or worn bearings, bent armature shaft allowing armature to drag. • Shorted armature. This can be further checked on a growler after disassembly. • Grounded armature or fields. Check further after disas­ sembly. 3. Failure to operate with high current draw indicates: • A direct ground in the terminal or fields. • “ Frozen” bearings (this should have been determined by turning the armature by hand). 4. Failure to operate with no current draw indicates: • Open field circuit. This can be checked after disassembly by inspecting internal connections and tracing circuit with a test lamp. • Open armature coils. Inspect the commutator for badly burned bars after disassembly. • Broken brush springs, worn brushes, high insulation be­ tween the commutator bars or other causes which would pre­ vent good contact between the brushes and commutator. 5. Low no-load speed and low current draw indicates: • High internal resistance due to poor connections, defec­ tive leads, dirty commutator and causes listed under Number 4. 6. High free speed and high current draw usually indicate shorted fields. If shorted fields are suspected, replace the field coil assembly. Also check for shorted arm ature, using a growler. Fig. 6D-9E--Starter Unit Repair 1 of 6 LIGHT TRUCK SERVICE MANUAL 6D-62 ENGINE ELECTRICAL S TA R T E R DI SASSEMBLY DRIVE GEAR RETURN PLUNGER HOUSING SOLENOID SPRING END FRAME INSULATOR COMMUTATOR END FRAME THRUST WASHER RETAINER FIBER WASHER FIELD FRAME SNAP RING WASHER CENTER CLUTCH AND D RIVE ASM. ARMA TUR E BEARING 7. Remove screw from field coil connector and solenoid mounting screws. Rotate solenoid 90? and remove along with plunger return spring. Solenoid may now be serviced without further starter disassembly at this time. 8. Remove 2 through b o lt, then remove commutator end frame (diesel only, remove insulator) and washer. 9. Remove field frame assembly from drive gear housing (On diesel starter, armature remains in drive end frame.) SHIFT LEVER A N D PLUNGER REMOVAL REMOVE DR I VE A SSE MB LY FROM S H A F T SHIFT LEVER PIVOT BOLT ROLL PIN PLUNGER ^ m hm ^ FIBER ^ A R MATURE S H A FT ^W ASHER ^ THRUST WASHER RETAINER RETURN SPRING r SHIFT CENTER/ BEARING LEVER D RIVE GEAR HOUSING Steps 10 and 11 are required only on diesel starters. 10. Remove shift lever pivot bolt. 11. Remove center bearing screws (25 MT only) and remove drive gear housing from armature shaft. Shift lever and plunger assembly will now fall away from starter clutch. CLUTCH AND D R IV E ASSEMBLY snap RING 12. If necessary to remove overrunning clutch from armature shaft, proceed as follows: a. Remove thrust washer or collar from armature shaft. b. Slide a 5/8" deep socket or piece of pipe of suitable size over shaft against retainer as a driving tool. Tap tool to move retainer off snap ring. c. Remove snap ring from groove in shaft. If snap ring is distorted, it will be necessary to use a new one on reassem­ bly. d. Remove retainer, clutch assembly (also fiber washer and center bearing on diesel) from armature shaft. 13. The shift lever and plunger may be disassembled at this time by removing the roll pin. Fig. 6D-1 O E-Starter Unit Repair 2 of 6 ENGINE ELECTRICAL 6D-63 REPLACE BR US H HOLDER (SMALL 5MT S T A R TE R ) ( S T A N D A R D S T AR TE R ) PIVOT P I N - ^ O INTEGRAL BRUSH BRUSH HOLDER FIELD FRAME (INSULATED) ASSEMBLY BRUSH SUPPORT V BRUSH H O L D E R V V (G R O U N D E D )W \ J BRUSH HOLDER SPRING 14. lows: ROUTE WIRE BRUSH HOLDER AS SHOWN SUPPORT If necessary to replace brush holder parts, proceed as fol­ a. Remove brush holder pivot pin which positions one insulated and one grounded brush. b. Remove brush spring. c. Replace brushes as necessary. a. Remove brush holder from brush support. b. Remove screw from brush holder and separate brush and holder. c. Inspect brush holder for wear or damage. d. Replace brushes and/or holders as necessary. CLEANING INSPECTION AND TESTS TESTING S H U N T COIL FOR OPEN TO TEST LIG HT GROUNDED BRUSH 15. Clean all starting m otor p arts, but DO NOT USE GREASE DISSOLVING SOLVENTS FOR CLEANING THE OVERRUNNING CLUTCH, ARMATURE, AND FIELD COILS, solvent would dissolve the grease packed in the clutch and would damage armature and field coil insulation. 16. Inspect armature commutator, shaft and bushings, over­ running clutch pinion, brushes and springs for discoloration, damage or wear. Replace as required. 17. Check fit of armature shaft in bushing in drive housing. Shaft should fit snugly in the bushing. If the bushing is worn, it should be replaced. 18. Inspect armature commutator. If commutator is rough, it should be turned down. Do not undercut or turn to less than 1.65(T O.D. Do not turn out-of-round commutators. Inspect the points where the armature conductors join the commutator bars to make sure they have a good connection. A burned com­ mutator bar is usually evidence of a poor connection. 19. If test equipment is available: a. Check the armature for short circuits by placing on growler and holding hack saw blade over armature core while armature is rotated. If saw blade vibrates, armature is shorted. Recheck after cleaning between the commutator bars. If saw blade still vibrates, replace the armature. b. Using a test lamp, place one lead on the shunt coil ter­ minal and connect the other lead to a ground brush. This test should be made from both ground brushes to insure con­ tinuity through both brushes and leads. If the lamp fails to light, the field coil is open and will require replacement. Fig. 6 D -1 1 E -S ta rte r Unit Repair 3 of 6 LIGHT TRUCK SERVICE MANUAL 6D-64 ENGINE ELECTRICAL TESTING SE R I ES COIL FOR OPEN TESTI NG S OL E N OI D WINDINGS SERIES COIL CONNECTION IN SULATED BRUSH c. Using a test lamp, place one lead on the series coil ter­ minal and the other lead on the insulated brush. If the lamp fails to light, the series coil is open and will require repair or replacement. This test should be made from each insulated brush to check brush and lead continuity. TESTING SE RI ES COIL FOR G R O U N D THESE TWO T ER M IN A L S MUST BE SEPARATED AND NOT TOUCHIN G A GROUND D URIN G TEST INSULATED BRUSH GROUNDED BRUSH HOLDER e. Check the current draw of the solenoid winding as fol­ lows: If solenoid is not removed from starting motor, the connec­ tor strap terminals must be removed from the terminal on the solenoid before making these tests. Complete tests in a minimum of time to prevent overheating of the solenoid. To check hold-in winding, connect an ammeter in series with 12-volt battery and the “ switch” terminal on the solenoid. Connect a voltmeter to the “ switch” terminal and to ground. Connect carbon pile across battery. Adjust the voltage to 10 volts and note the ammeter reading. It should be 14.5 to 16.5 amperes for all starting motors. To check both windings, connect as for previous test Ground the solenoid motor terminal. Adjust the voltage to 10 volts and note the ammeter reading. It should be 41 to 47 am­ peres for all starting motors. NOTE: Current will decrease as windings heat up. Current draw readings that are over specifications indicate shorted turns or a ground in the windings of the solenoid and the solenoid should be replaced. Current draw readings that are under specifications indicate excessive resistance. No reading indicates an open circuit. Check connections then replace sole­ noid if necessary. d. On starters with shunt coil, separtate series and shunt coil strap terminals during this test. Do not let strap terminals touch case or other ground. Using a test lamp place one lead on the grounded brush holder and the other lead on either insulated brush. If the lamp lights, a grounded series coil is indicated and must be repaired or replaced. Fig. 6D -12E --Starter Unit Repair 4 of 6 LIGHT TRUCK SERVICE MANUAL E N G IN E ELECTRICAL 6 D -6 5 STARTER ASSEMBLY I NSTALLING R E T A I N E R , WASHER A N D RING 20. Assemble the armature and clutch as follows: a. Lubricate drive end of armature shaft with lubricant 1960954 or equivalent. b. Install center bearing (diesel starters) with bearing to­ ward the armature winding. Then install the fiber washer on the armature shaft. c. Slide clutch assembly onto armature shaft with pinion away from armature. d. Slide retainer onto shaft with cupped side facing the end of shaft. e. Install snap ring into groove on armature shaft. f. Install thrust washer on shaft. g. Position retainer and thrust washer with snap ring in be­ tween. Using two pliers, grip retainer and thrust washer or collar and squeeze until snap ring is forced into retainer and is held securely in groove in armature shaft. 21. Lubricate drive gear housing bushing with lubricant 1960954 or equivalent. 22. Engage shift lever yoke with clutch and slide complete assembly into drive gear housing. On non-diesel starters the shift lever may be installed in drive gear housing first. 23. Install the center bearing screws (25 MT diesel only) and the shift lever pivot bolt. Tighten securely. 24. Install solenoid assembly. 25. Apply sealer, No. 1050026 or equivalent to solenoid flange where field frame contacts it. 26. Position field frame against drive gear housing on align­ ment pin using care to prevent damage to brushes. 27. Lubricate commutator end-frame bushing with lubricant 1960954 or equivalent. 28. Install washer on armature shaft and slide end frame onto shaft, then install and tighten through-bolts. On diesel starter, install insulator and then end frame onto shaft. Then install through bolts, making sure they pass through bolt holes in in­ sulator. 29. Connect the field coil connector to the solenoid terminal. 30. Check pinion clearance as outlined under PINION CLEARANCE. Fig. 6 D -1 3 E -S ta rte r Unit Repair 5 of 6 LIGHT TRUCK SERVICE MANUAL 6D-66 ENGINE ELECTRICAL CHECKING PINION C LE A R AN CE PRESS ON C L U T C H TO R E M O V E S LA C K \v P IN IO N , R E T A IN E R 010 FEELER^ to .1 4 0 ' P IN IO N CLEARAN CE J When the starter motor has been disassembled or the sole­ noid has been replaced, it is necessary to check the pinion clearance. Pinion clearance must be correct to prevent the but­ tons on the shift lever yoke from rubbing on the clutch collar during cranking. 31. Disconnect the motor field coil connector from the sole­ noid motor terminal and insulate it carefully. 32. Connect one 12 volt battery lead to the solenoid switch terminal and the other to the starter frame. 33. Flash a jumper lead momentarily from the solenoid motor terminal to the starter frame. This will shift the pinion into cranking position and it will remain so until the battery is dis­ connected. 34. Push the pinion back as far as possible to take up any movement, and check the clearance with a feeler gage. The clearance should be .010" to .140". Means for adjusting pinion clearance is not provided on the starter motor. If the clearance does not fall within limits, check for improper installation and replace all worn parts. G AG E Fig. 6d-14E--S tarter Unit Repair 6 of 6 LIGHT TRUCK SERVICE MANUAL ENGINE ELECTRICAL 6D-67 SPECIFICATIONS GENERATOR MODEL N O . APPLICATION 1102394 All 1-6 (Base) 1102491 (Except G -2 0 , 30 & 1102889 FIELD CURRENT COLD OUTPUT* AMPS 27°C (80°F) AMPS @ @ 12 VOLTS 5000 RMP 4519 4 -4 .5 33 37 4521 4 -4 .5 38 42 4522 4 -4 .5 57 61 4525 4 -4 .5 76 80 DELCO REMY SPEC. N O . RATED HOT O U T P U T ** AMPS P-Truck) All C-K -G Truck Base V-8 (Except K31303 & G 30003) 1102485 292 L-6 (L25) (Base) 1102841 (G -20, 30 & P-Truck) 1102887 All P-Truck Base V-8 (Except P31832) 1102480 P31832 Truck (Base) 1102486 1102886 All L-6 or V -8 with RPO K76 1102888 454 V-8 (FL8) (Base) K31303 & G 30003 Truck Base V-8 1101016 O ptio nal (COPO) 1101028 ^G enerator tem perature approxim ately 27°C. (80°F.). **A m b ien t tem perature 27°C. (80°F.). Note: The only difference between generators within each group above is the position end fram e is rotated. LIGHT TRUCK SERVICE MANUAL 6D-68 ENGINE ELECTRICAL SPECIFICATIONS DISTRIBUTOR & SPARK PLUGS Distributor and spark plug specifications are shown in the Emission Control Chart in Section 6E Specifications. BATTERY MODEL N O . 85-4 85-5 COLD CRANK RATE AMPS FOR 25 AMP. RESERVE @ 0°F (-18°C) LOAD TEST CAPACITY (MINUTES) 250 L-6 (LD4) 275 Amps 130 60 292 L-6 (L25) 350 Amps 170 80 465 Amps 230 125 43 0 Amps 210 100 APPLICATION 305 V-8 (LG9) 350 V -8 (LS9) 400 V-8 (LF4) 89-5 454 V-8 (LF8) RPO UA1 87-5 RPO TP2 STARTING MOTOR MODEL N O . 1108778 APPLICATION 250 L-6 (LD4) SPEC. N O . FREE SPEED VOLTS AMPERES RPM 3573 9 5 0 -8 0 * 5 5 00 -105 00 (C & K-10) 1108779 250 L-6 (LD4) (G -Van) 3573 9 5 0 -8 0 * 5 5 0 0 -105 00 1108780 292 L-6 (L25) 2438 9 5 0 -8 0 * 3 5 00 -600 0 1109056 305 V-8 (LG9) (C & K) 3573 9 5 0 -8 0 * 55 00 -105 00 1109798 305 V-8 (LG9) (G -Van) 3573 9 5 0 -8 0 * 5 5 0 0 -105 00 1109052 350 V-8 (LS9) 3563 9 6 5 -9 5 * 7500-10500 1108776 400 V -8 (LF4) 3563 9 6 5 -9 5 * 7500-10500 454 V -8 (LF8) ^Includes Solenoid L ig h t TRUCK SERVICE MANUAL Insert Chart 6D-S 2 ENGINE EMISSION CONTROLS 6E-1 SECTION 6E ENGINE EMISSION CONTROLS CONTENTS General Description........................................................... Positive Crankcase V entilation-(PC V )....................... Exhaust Gas Recirculation-(EGR).............................. Early Fuel Evaporation(EFE)....................................... Air Management S y s te m ............................................... Thermostatic Air Cleaner-TA C ........................... .......... Throttle Return C o n tro l-(T R C ).................................. Carburetor C alibration................................................... Distributor Calibration................................................... Catalytic C o n v e rte r ......................................................... Diagnosis............................................................................... PCV Sy stem ....................................................................... EGR S y s te m ...................................................................... 6E-1 6E-1 6E-1 6E-1 6E-2 6E-2 6E-3 6E-3 6E-4 6E-4 6E-4 6E-4 6E-5 GENERAL DESCRIPTION POSITIVE CRANKCASE VENTILATION (PCV) SYSTEM All engines have closed Positive Crankcase Ventilation System to provide more complete scavenging of crankcase vapors (Fig. 6E-1). Ventilation air is drawn from the dirty air side of the air cleaner, through a hose, down into the crankcase, up through the ventilator valve, through a hose and into the intake manifold. Intake manifold vacuum draws any fumes from the crankcase to be burned in the engine. Diagnosis and service procedures for the PCV system can be found in this section. Belt Driver Air P u m p ...................................................... 6E-6 Emission F ailu re............................................................... 6E-8 Pulse Air Injection........................................................... 6E-9 On-Vehicle Service....;........................................................ 6E-9 Positive Crankcase Ventilation...................................... 6E-9 Exhaust Gas Recirculation............................................ 6E-9 Early Fuel Evapo ratio n................................................ 6E-13 Air Injection R eaction.................................................. 6E-15 Pulse Air Injection......................................................... 6E-20 Thermostatic Air C le a n e r ........................................... 6E-20 Throttle Return C o n tro l............................................... 6E-24 Detonation Sensor.......................................................... 6E-27 Vehicle Emission Control Information Label............ 6E-28 evaporation and more uniform fuel distribution to aid cold driveability. It also reduces the length of time carburetor choking is required making reductions in exhaust emission levels possible. EFE systems may use a valve which increases the exhaust gas flow under the intake manifold during cold engine operation. The valve is vacuum operated and is controlled by a thermal vacuum switch (TVS) which applies vacuum when the coolant temperature is below the calibra­ tion value. Diagnosis and service procedures of the EFE system can be found in this section. EXHAUST GAS RECIRCULATION (EGR) SYSTEM The Exhaust Gas Recirculation (Fig. 6E-2) is used on all engines except those equipped with H.D. Emissions. It meters exhaust gas into induction system for recirculation through the combustion cycle to reduce oxides of nitrogen emissions. The EGR valve remains closed during periods of engine idle and deceleration to prevent rough idle from excessive exhaust gas dilution in the: idle air/fuel mixtures. It also remains closed at wide open throttle to prevent power loss. Diagnosis and service procedures for the EGR system can be found in this section. EARLY FUEL EVAPORATION (EFE) SYSTEM The EFE system is used to provide a source of rapid heat to the engine induction system during cold driveway. Rapid heating is desirable because it provides for quick fuel Hinfr COMBUSTIBLE MIXTURE Fig. 6E-1--PCV System-Typical LIGHT TRUCK SERVICE MANUAL 6E-2 ENGINE EMISSION CONTROLS Fig. 6E -2 --E G R System -Typical AIR MANAGEMENT SYSTEM Two different types of air management systems are used on light duty trucks. An air injection reactor (A IR ) (Fig. 6E-3) is used on some engines to provide additional oxygen to continue the combustion process after the exhaust gases leave the combustion cham ber. A belt driven air pump provides pressurized air which is injected into the exhaust port of the cylinder head or exhaust pipe and then into the exhaust system. The A IR system operates at all times and will bypass air only for a short duration of time during decelera­ tion and at high speeds. A diverter valve performs a bypass function, and the check valve protects the air pump from damage by preventing a back flow of exhaust gas. Diagnosis and service procedures for air injection reactor systems are is in this section. The Pulse Air Injection Reactor System consists of four pulse air check valves. The check valves are connected by tubes to the exhaust ports. The firing of the engine creates a pulsating flow of exhaust gases which are positive or negative pressure. A negative pressure at the pulse air valves results in the flow of fresh air into the exhaust system. If pressure is positive the check valve is forced closed and no exhaust gas will flow past the valve into the fresh air supply line. A deceleration valve is used on some L6 and California V8 models to prevent backfiring in the exhaust system during decleration. W hen deceleration causes a sudden vacuum increase in the vacuum signal line, the pressure differential on the diaphragm will overcome the closing force of the spring, opening the valve and bleeding air into the intake manifold. Air trapped in the chamber above the vacuum dia­ phragm will bleed at a calibrated rate through the delay valve portion of the integral "Check and Delay Valve, reducing the vacuum acting on the diaphragm. When the vacuum load on the diaphragm and the spring load become equal, the valve assembly will close, shutting off the air flow into the intake manifold. The check valve portion of the "Check and Delay LIGHT TRUCK SERVICE MANUAL Valve" provides quick balancing of chamber pressure when a sudden decrease in vacuum is caused by accleration rather than deceleration. THERMOSTATIC AIR CLEANER (THERMAC) The Thermostatic Air Cleaner (T H E R M A C ) is on all engines. The TAC uses a damper door in the air cleaner inlet, controlled by a vacuum diaphragm motor to mix pre­ heated and non pre-heated air entering the air cleaner to maintain a controlled air temperature into the carburetor. The vacuum motor is modulated by a temperature sensor in the air cleaner. The pre-heating of the air cleaner inlet air allows leaner carburetor and choke calibrations resulting in lower emission levels, while maintaining good driveability. The pre-heated air is obtained by drawing inlet air through stove attached to the exhaust manifold. Diagnostics and service procedures for the thermostatic air cleaner can be found in this section. ENGINE EMISSION CONTROLS 6E-3 N O R M A L F LO W SHOW N B Y B L A C K A R R O W S : BY-PASS C O N D IT IO N S SHOW N BY CROSS H A T C H E D A R R O W S TUBE ASSEM BLY HOSE CHECK V A L V E A IR IN IN JE C T IO N TUBE H IG H SPEED BY-PASS A IR PUMP E X H A U S T PO RT D E C E L E R A T IO N BY-PASS D IV E R T E R VALVE M A N IF O L D V A C U U M SO URCE Fig. 6E-4--AIR System THROTTLE RETURN CONTROL (TRC) SYSTEM The T R C system used on heavy duty emission vehicles consists of three major components: 1. Throttle Lever A ctuator - Mounted as part of the carburetor assembly, this device opens the primary throttle blades a preset amount in excess of curb idle when engine vacuum is applied to it. This actuating vacuum is controlled by a separate solenoid control valve. 2. Solenoid Vacuum Control Valve - Mounted separately from the carburetor, this off-on valve is held open above a present nominal engine speed by a signal from an electronic speed sensor. The valve when open allows a vacuum signal to be applied to the throttle lever a c tu a to r as long as the present engine speed is exceeded. 3. Electronic Speed Sensor - Mounted separately from the solenoid vacuum control valve, this switching device monitors engine speed at the distributor and supplies a continuous electrical signal to the solenoid vacuum control valve as long as the preset engine speed is exceeded. CARBURETOR CALIBRATION While the carburetor’s main function is to provide the engine with a combustible air/fuel mixture, the carburetor calibration is critical to maintaining proper emission levels. The carburetor’s idle, off-idle, main metering, power enrichment, and accelerating pump systems are calibrated to provide the best possible combination of engine perform­ ance, fuel economy and exhaust emission control. C a r ­ buretor adjustments and service must be performed using the recommended procedures to insure engine exhaust emission levels remain within offical limits. See Section 6C, Engine Fuel, for carburetor adjust­ ment specifications and recommended service procedures. LIGHT TRUCK SERVICE MANUAL 6E-4 ENGINE EMISSION CONTROLS DISTRIBUTOR CALIBRATION CATALYTIC CONVERTER The distributor is an integral part of the engine ignition system and the distributor calibration is an important part of exhaust emission control. The distributor is calibrated to provide the best engine performance and fuel economy at varying speeds and loads while remaining within exhaust emission limits. Distributor diagnostics and service procedures are in Section 6D, Engine Electrical. The catalytic converter is an emission control device added to the exhaust system of light duty emission vehicles to reduce hydrocarbon and carbon monoxide from the exhaust gas stream. Refer to Section 6F, Engine Exhaust System, for catalytic converter service procedures and diagnostics. DIAGNOSIS PCV SYSTEM DIAGNOSIS C O N D IT IO N POSSIBLE CAUSE CORRECTION Slow, unstable idle, frequent stalling. Valve completely plugged or stuck. Replace valve. Restricted filter Replace filter, clean system. PCV system plugged. Replace valve. Leak in closed ventilation system. Clean system as required. Oil in a ir cleaner. Inspect for leaks to atmosphere and correct as necessary. ^ Fig. 6E-5--PCV System Diagnosis LIGHT TRUCK SERVICE MANUAL ■'I >"■ i' . . t **!1fli * . ■■J-Sx* * ’TO1* ENGINE EMISSION CONTROLS 6E-5 EGR DIAGNOSIS CONDITION Engine idles abnormally rough and/or stalls. POSSIBLE CAUSE EGR valve vacuum hoses misrouted. Check EGR valve vacuum hose routing. Correct as required. Leaking EGR valve. EGR valve vacuum hose misrouted. Check EGR valve for correct operation. Check EGR attaching bolts for tightness. Tighten as required. If not loose, remove EGR valve and inspect gasket. Replace as required. Perform EGR-TVS functional check. Check vacuum from carburetor EGR port with engine at stabilized operating temperature and at curb idle speed. (See checking EGR valve.) Check EGR valve vacuum hose routing. Correct as required. Check for loose valve. Torque valve. Failed EGR-TVS (TVS open below 130°F.) Same as listing in "Engine Idles Abnormally Rough and/or Stalls” condition. Clean EGR passage deposits. Perform EGR System check. EGR valve gasket failed or loose EGR attaching bolts. EGR-TVS. Improper vacuum to EGR valve at idle. Engine runs rough on light throttle acceleration and has poor part load performance. Engine stalls on decelerations. Sticky or binding EGR valve. Wrong or no EGR gasket(s) and/or Spacer. Transducer control valve blocked or air flow restricted. Restriction in EGR vacuum line or vacuum signal tube. Part throttle engine detonation. (NOTICE: Non-Functioning EGR valve could contribute to part throttle detonation. Detonation can also be caused by several other engine variables. Perform ignition and carburetor related diagnosis.) Engine starts but immediately stalls when cold. (NOTICE: Stalls after start can also be caused by carburetor problems.) CORRECTION Sticking or binding EGR valve. Transducer control valve blocked or air flow restricted. Insufficient exhaust gas recirculation flow during part throttle accelerations. Control valve blocked or flow restricted. EGR valve hoses misrouted. EGR-TVS system malfunctioning when engine is cold. Install new gasket(s), install spacer (if used), torque attaching parts. Check transducer control valve operation (See Checking Back Pressure EGR Valve). Check EGR vacuum lines for kinks, bends, etc. Remove or replace hoses as required. (See Checking EGR Valve). Check EGR valve for excessive deposits causing sticky or binding operation. Perform EGR System Check. Check internal control valve operation (See Checking EGR Valve). Check EGR valve hose routing. Check EGR valve operation. Repair or replace as required. Check EGRTVS as listed in "Engine Idles Abnormally Rough and/or Stalls" section. Replace valve as required. Check EGR passages and valve for excessive deposit. Clean as required. Check EGR per service procedure. Check EGR valve hose routings. Perform EGR-TVS functional check. Fig. 6E-6--EGR Diagnosis LIGHT TRUCK SERVICE MANUAL 6E-6 ENGINE EMISSION CONTROLS A.I.R. Trouble Diagnosis NOTE: The A.I.R. system is not completely noise­ less. Under normal conditions, noise rises in pitch as engine speed increases. To determine if excessive noise is the fault of the air injection CONDITION Excessive belt noise. system, disconnect the drive belt and operate the engine. If noise does not exist, proceed w ith diagnosis. POSSIBLE CAUSE CORRECTION 1. Loose belt. 1. Tighten to spec. 2. Seized pump. 2. Replace pump. 3. Excessively tight belt. Excessive pum p noise. Chirping. Insufficient break-in. Run vehicle 10-15 miles (16-24 kilometers) at turnpike speeds — recheck. Excessive pum p noise, chirping, rum bling, or knocking. 1. Leak in hose. 1. Locate source of leak using soap solution and correct. 2. Loose hose. 2. Reassemble and replace or tighten hose clamp. 3. Hose touching other engine parts. 3. Adjust hose position. 4. Diverter valve inoperative. 4. Replace diverter valve. 5. Check valve inoperative. 5. Replace check valve. 6. Pump m ounting fasteners loose. 6. Tighten m ounting screws as specified. 7. Pump failure. 7. Replace pump. Fig. 6E-7--A.I.R. Diagnosis LIGHT TRUCK SERVICE MANUAL ENGINE EMISSION CONTROLS 6E-7 A.I.R. Trouble Diagnosis (Cont'd.) CONDITION No air supply (accelerate engine to 1500 rpm and observe air flo w from hoses. If the flo w increases as the rpm 's increase, the pum p is fun ctio ning normally.) If not, check possible cause. POSSIBLE CAUSE CORRECTION 1. Loose drive belt. 1. Tighten to specs. 2. Leaks in supply hose. 2. Locate leak and repair or replace as required. 3. Leak atfitting(s). 3. Tighten or replace clamps. 4. If air is expelled through diverter m uffler w ith vehicle at idle, replace diverter valve. 4. Diverter valve leaking. 5. Diverter valve inoperative. (Usually accompanied by backfire during deceleration.) 5. Replace diverter valve. 6. Check valve inoperative. 6. Blow air through hose tow ard air manifold. If air passes, function is normal. If air can be sucked from m anifold, replace check valve. 7. Pump pressure relief plug leaking or damaged. 7. Replace pressure relief plug. Centrifugal filte r fan damaged or broken. Mechanical damage. Replace centrifugal filte r fan. Exhaust tube bent or damaged. Mechanical damage. Replace exhaust tube. Poor idle or driveability. A defective A.I.R. pump cannot cause poor idle or driveability. Do not replace A.I.R. pump. Fig. 6E-8--A .I.R . Diagnosis LIGHT TRUCK SERVICE MANUAL 6E-8 ENGINE EMISSION CONTROLS POSSIBLE CAUSES OF EMISSIONS TEST FAILURES EXCESSIVE EMISSIONS POSSIBLE CAUSES EXPLANATION Hydrocarbons (HC) * Excessive hydrocarbons are caused by an air fuel m ixture that is not burning completely. • Engine not at normal operating temperature. • Disconnected, obstructed, leaking, or misrouted vacuum hoses. • Vacuum leaks. • Maladjusted idle speed. • Maladjusted idle m ixture - if plugs are removed. • Maladjusted initial spark tim ing. • Spark plugs, wires or d istrib u to r cap. • Improper operation of A l R or Pulsair system. • Lead contamination o f catalytic converter (check fo r absence o f fille r neck restrictor). Carbon m onox­ ide (CO) * Excessive carbon m onox­ ide emissions are due to a m ixture that is rich. • • • • • • • • • • Oxides of nitrogen (NOx ) * Excessive oxides o f nitrogen are generally due to high tempera­ tures in the combustion chamber. Engine not at normal operating temperature. Maladjusted idle m ixture if plugs are removed. Im properly adjusted/sticking choke. Stuck PCV valve or obstructed PCV hose. Lead contam ination o f catalytic converter (check fo r absence o f fille r neck restrictor). Improper operation o f A l R or Pulsair system. Leaking carburetor fuel passages or gaskets. Carburetor flo a t level. Stuck carburetor power piston. Restricted air cleaner element. • Obstructed/leaking/misrouted vacuum lines. • Faulty EGR temperature sensor controls. • Improper operation o f the EGR system. • Incorrect EGR valve fo r engine type. • Plugged EGR passages. • Inoperative Thermae. • Maladjusted initial spark tim ing. • Improper operation o f d istrib u to r centrifugal or vacuum spark advance. Excessive emissions o f both hydrocarbons and carbon monoxide are related to an extrem ely rich air/fuel m ixture. A rich air/fuel m ixture increases CO emissions, but if the m ixture is too rich, it w ill not burn completely. This unburned fuel contributes to high hydrocarbon emissions. Check fo r possible causes as stated in the HC and CO section. Check co-related causes first. LIGHT TRUCK SERVICE MANUAL ENGINE EMISSION CONTROLS P.A.I.R. FAILURE DIAGNOSIS 1. A hissing noise may indicate a defective pulse air valve or improper torque at manifold. Inspect pulse air valve. 2. If one or more check valves have failed, exhaust gas will enter the carburetor through the air cleaner and cause poor driveability indicated by a surge or poor perform­ ance. Check pulse air valves. Be sure pulse air pipe extension tubes are installed in exhaust manifold. a. If exhaust gases pass through the pulse air valve, excessive heat is transmitted to the rocker cover 6E-9 plenum, indicated by burned off paint. Also, rubber grommets and hose will deteriorate. Failure could also be indicated by a hissing noise. Repair rocker cover plenum seals and replace grommets and hose as required. b. If rubber hose to air cleaner deteriorates, particles may enter carburetor causing poor driveability. It will be necessary to clean carburetor, and remove particles from pulse air plenums and connecting pipe. ON-VEHICLE SERVICE POSITIVE CRANKCASE VENTILATION An engine which is operated without any crankcase ventilation can be dam ag ed seriously. Therefore, it is important to replace the PCV valve at intervals shown in Section OB. If an engine is idling too slow or rough, this may be caused by a clogged ventilator valve or plugged hose; therefore, never adjust the carburetor idle with­ out first checking the PCV valve and hose. NOTICE: With this system, any blow-by in excess of the system capacity (from a badly-worn engine, sustained heavy load, etc.) is exhausted into the air cleaner and is drawn into the engine. Proper operation of the PCV System is dependent upon a sealed engine. If oil sludging or dilution is noted, and the PCV System is functioning properly, check engine for possible cause and correct to ensure th a t system will function as intended. Removal 1. Remove PCV valve from intake manifold or rocker arm shaft cover. 2. Run the engine at idle. 3. Place your th u m b over end of valve to check for vacuum. If there is no vacuum at valve, check for plugged hoses or valve. Replace plugged and/or deteri­ orated hoses. 4. Shut off the engine and remove PCV valve. Shake valve and listen for the rattle of check needle inside the valve (Fig. 6E-11). If valve does not rattle, replace valve (Fig. 6E-10). 5. After installing a new PCV valve, readjust engine idle if necessary. EXHAUST GAS RECIRCULATION (EGR) A backpressure EG R valve is used on Light Duty Emission class engines. The valve opening is determined by the amount of vacuum received from a ported source on the carburetor and the amount of backpressure in the exhaust system. Two different types of backpressure EGR valves are used. A positive tra nsdu c e r valve (Fig. 6E-12) and a negative tran sdu ce r valve (Fig. 6E-13). The negative transduced backpressure valve is used on engines with a relatively low backpressure to provide the desired opening point and flow rate. The EGR system requires the use of unleaded fuel. EGR Valve Identification Refer to figures 6E-14 and 6E-15 for identification of the different EG R valves. LIGHT TRUCK SERVICE MANUAL 6E-10 ENGINE EMISSION CONTROLS POSITIVE BACK PRESSURE EGR VALVE CO N TR O L V A LVE OPEN ORIFICE O P E N IN G .0 3 0 (SEE O P T IO N A L C O N S T R U C T IO N ) TRANSDUCER V A C U U M S IG N A L D IA P H R A G M TUBE PLATE O P T IO N A L C O N S T R U C T IO N ORIFICE O P E N IN G .020 EXHAUST I I EXHAUST GAS G A S (IN ) Fig. 6E-12--Positive Backpressure EGR Valve LIGHT TRUCK SERVICE MANUAL ENGINE EMISSION CONTROLS 6E-11 POSITIVE BACK P R E SS U RE EGR V A L V E NOTE: ID E N T IF Y P O S IT IV E EGR V A L V E B Y D IA P H R A G M P L A T E D ESIG N D IA P H R A G M P L A T E A S S E M B L Y Fig. 6E-14-Positive EGR Identification N E G A TI V E BACK P R ES SU R E EGR V A L V E NOTE: ID E N T IF Y N E G A T IV E EGR V A L V E B Y D IA P H R A G M P L A T E D E S IG N D IA P H R A G M P L A T E A S S E M B L Y Fig. 6 E -1 5 -N e g a tiv e EGR Identification LIGHT TRUCK SERVICE MANUAL 6E-12 ENGINE EMISSION CONTROLS Checking EGR System Operation 1. Place finger under E G R valve and push on diaphragm plate. Diaphragm should move freely from open to closed position. If it does not move freely replace valve. C A U T IO N :lf va lve is hot it m a y be necessary to w e a r gloves to avoid burning fingers. 2. Hook up vacuum gage between EG R signal tube and vacuum hose. 3. W ith vehicle in " P a r k " or " N e u tr a l" and engine running open throttle to obtain at least 5 " of vacuum at EG R be careful not to overspeed engine neutral. Engine m ust be at coolant operating te m pe ra tu re (90°C (approx. 195°F). 4. Remove vacuum hose from EG R signal tube and check for diaphragm plate to move downward (valve closed). 5. Replace vacuum hose and check for diaphragm plate tomove upw ard (valve open). Engine speed should decrease. A vibration of the diaphragm plate may be noticed on back pressure E G R valves. This does not indicate a bad valve or require correction. Diaphragm doesn't move: 1. Check engine vacuum, it should be at least 5" at EGR valve with engine running and throttle open. If no vacuum is present, find the cause (hose routing not correct, plugged or leaking hose or carburetor port). 2. Make sure engine is at operating temperature. 3. On back pressure E G R valves, check tran sdu cer control valve operation (See Checking N egative or Positive E G R Valve). Diaphragm moves with no change in engine speed: Check EGR manifold passages for blockage (clean if blocked). If cause is not found, check EGR valve (See Checking Negative or Positive EG R Valve). Functional Checks Checking N e g a tiv e Backpressure EGR V alv e 1. Check hose routing (Refer to Vehicle Engine Emission Control Information Label). 2. Check EGR valve signal tube orifice for obstructions. 3. Hook up vacuum gage between EG R valve and car­ buretor and check vacuum (engine must be at operat­ ing temperature approx. 90°C (195°F). With engine running at approximately 3000 RPM their should be at least 17 kPa (5 ") of vacuum. 4. Check EG R-TV S for correct operation (see EGR-TVS functional check). 5. Valve check: (valve can be left on or removed from engine). a. Depress the valve diaphragm. b. With diaphragm still depressed hold a finger over source tube and release diaphragm. c. Check diaphragm and seat for movement. Valve is good if it takes over 20 seconds for the diaphragm to move to the seated position (valve closed). d. Replace EG R valve if it takes less than 20 seconds to move to the seated position. LIGHT TRUCK SERVICE MANUAL Checking Positive Backpressure EGR Valve 1. Check hose routing (Refer to Vehicle Emission Control Information Label). 2. Check EG R valve signal tube orifice for obstructions. 3. Check EGR-TV S for correct operation. (See EGRTVS functional check). 4. Valve check. a. Remove EG R valve from vehicle. b. Apply a constant external vacuum 34 kPa (1 0 ") or more supply to EGR vacuum signal tube. c. Valve should not open. If it does transducer control valve is stuck closed and E G R valve m ust be replaced. d. With the vacuum supply still applied, direct a stream of air from a low pressure source (103 kPa 15 psi maximum) into the valve exhaust gas intake. e. Valve should open completely. If it does not open at all transducer control valve is stuck open and EGR valve must be replaced. f. If E G R valve and transducer control valve are both operating clean the EG R mounting surfaces and install valve. EGR Valve Replacement 1. Disconnect EG R valve vacuum hose at valve. 2. Remove bolts or nuts holding EG R valve on manifold (Fig. 6E-15a). 3. Remove EGR valve from manifold. 4. Clean EG R mounting surfaces. 5. Reassemble replacement EG R valve on intake mani­ fold using new gasket(s). Install spacer (if used). Torque attachments to correct torque. 6. Connect vacuum hose to valve. EGR Manifold Passage If inspection of EGR passages in the inlet manifold indicates excessive build-up of deposits, the passages should be cleaned. Care should be taken to ensure that all loose particles are completely removed to prevent ehm from ENGINE EMISSION CONTROLS clogging the EGR valve or from being ingested into the engine. EGR Thermal Vacuum Switch (EGR - TVS) R eplacem ent 1. Drain engine coolant. 2. Disconnect vacuum lines from the thermal vacuum switch. 3. Remove switch. 4. Apply an approved sealer to threaded portion of switch. 5. Install switch and torque to 20 N-m (15 lbs. ft.). 6. Rotate switch head as required to align for proper hose routing. 7. Install vacuum hoses to switch. 8. Replace engine coolant and check level. EGR-TVS Functional Check - Hot The EG R Thermal Vacuum Delay Switch opens as coolant temperature increases, permitting the ported vac­ uum signal to reach the EG R valve. Check as follows: 1. Remove EGR valve vacuum hose at EGR valve and connect hose to a vacuum gage. 2. S ta rt engine. W ith transmission seelector lever in N e u tra l or Park open throttle partially. (Do not overspeed engine.) as throttle is opened, the vacuum gage should respond with an increase in vacuum reading. 3. If operation is satisfactory, remove gage and reconnect hose to EG R valve. If gage does not respond to throttle opening, proceed to Step 4. 4. Remove Carb-to-switch hose from switch and connect hose to vacuum gage. Repeat Step 2. 5. If vacuum gage responds to throttle opening, then switch is defective. Remove switch and replace with new part. If gage does not respond to throttle opening, then check for plugged hose or defective carburetor. EGR-TVS Functional Check - Cold This check can be used to diagnosis a stall after cold start or poor driveability immediately after cold start. The EGR thermal vacuum delay switch should be closed below a coolant temperature of 85°F (29°C) thereby blocking the ported vacuum signal from reaching the EGR valve below that temperature. Check as follows: 1. Drain coolant to below level of switch. 2. Disconnect vacuum lines and remove switch. 3. Inspect switch to make sure it is in good condition. 4. Connect a vacuum hose to lower nipple of switch, marked " C " or " C A R B " . Connect a vacuum gage to upper nipple, marked " E " or " E G R " . 5. Place switch in water at 75°F (24°C) and submerge completely for 2 m inutes while agitating water thoroughly. 6. Apply 12 in. hg. (-41 kPa) vacuum to hose on lower nipple of switch. Under this condition, the switch should be closed. 6E-13 Leakage of up to 2 in. hg. ( - 7 kPa) of vacuum in 2 minutes is allowable and does not mean a defective switch. 7 . If operation is satisfactory, reinstall switch. If switch is defective, replace with a new part. 8. Replace coolant and check level. NOTICE: EARLY FUEL EVAPORATION (EFE) Inspection (except 4.8L - 292 CID) • Visually inspect exhaust heat valve for d am age or binding linkage. • Check that linkage is connected and vacuum hoses are properly routed and connected. • Move exhaust heat valve by hand. If binding or stuck, free with manifold heat valve lubricant, G M Part No. 1050422 or equivalent. If valve cannot be freed, replace valve. Manifold Heat Valve Inspection (with 4.8L - 292 CID) • Visually inspect manifold heat valve for damage or binding. • Move valve by hand. If binding or stuck, free with manifold heat valve lubricant, G M Part No. 1050422 or equivalent. If valve cannot be freed, replace valve. Checking EFE System 1. With engine cold, position transmission in neutral or park and apply parking brake. 2. Start engine and observe movement of actuator rod and exhaust heat valve. Valve should move to its closed position. 3 . If valve does not close, disconnect hose at actuator and check for vacuum. • If there is vacuum, replace actuator. • If there is no vacuum, disconnect hose at TVS-tovacuum source. • If there is vacuum at hose, replace TVS. • If there is no vacuum, check for deteriorated hose and vacuum source to determine lack of vacuum. 4. W hen coolant reaches 180°F (82°C) (V8), or oil reaches 150°F (66°C) (six cylinder), the exhaust heat valve should move to its open position. 5. If valve does not move, disconnect hose at actuator and check for vacuum. • If there is vacuum, replace TVS. • If there is no vacuum, replace actuator. Coolant Temperature Thermal Vacuum Switch (TVS) - V8 R eplacem ent 1. Drain coolant below level of engine coolant outlet housing. 2. Disconnect hoses at TVS ports. 3 . Remove TVS. 4. Apply a soft setting sealant uniformly on replacement TVS male threads. No sealant should be applied to sensor end of TVS. LIGHT TRUCK SERVICE MANUAL 6E-14 ENGINE EMISSION CONTROLS Fig. 6 E -1 6 -E G R -T V S 4.1 L F e d eral 5. Install TVS, tighten to 120 pound inches (14N-m) and then hand torque clockwise as required to align TVS to accomodate hoses. 6. Connect hoses to TVS ports. 7. Add coolant as required. Oil Temperature Thermal Vacuum Switch (TVS) L6 Replacem ent 1. Disconnect hoses at TVS ports. 2. Remove TVS switch. 3. Install TVS switch. 4. Connect hoses to TVS ports. Actuator Assembly (Fig. 6E-18, 19, 20) The actuator assembly is located on a bracket attached to right exhaust manifold or mounted directly to the right or left exhaust manifold. Actuators which are remotely located on bracket are connected to the heat valve by a rod. Fig. 6E-17--EGR-TVS 5.0L and 5.7L California LIGHT TRUCK SERVICE MANUAL ENGINE EMISSION CONTROLS 6E-15 Replacem ent 1. Disconnect vacuum hose from actuator. 2. Remove fasteners holding a c tu a to r to mainifold or bracket. 3. If used, disconnect rod from actuator and remove. 4. Remove actuator. 5. Install actuator and rod (if used) reversing steps 1 through 4. Tighten nuts to 3 N-m (25 in. lbs.). Exhaust Heat Valve - V8 R eplacem ent 1. 2. 3. 4. 5. Remove crossover exhaust pipe. Disconnect rod from valve. Remove valve. Install valve and connect rod. Install crossover exhaust pipe. Exhaust Heat Valve - 4.1L R eplacem ent 1. Remove 2 nuts attaching actuator bracket-to-valve and exhaust manifold. 2. Remove bracket and disconnect rod from valve. 3. Remove 2 additional nuts from valve and remove valve. 4. Install valve reversing Steps 1 through 3. Manifold Heat Valve - 4.8 L R eplacem ent 1. Remove exhaust pipe to manifold nuts and lower exhaust pipe. 2. Remove heat valve and packings. 3. Reverse above steps to install. AIR INJECTION REACTOR (AIR) SYSTEM The Air Injection Reactor (A.I.R.) System consists of: an air injection pump (with necessary brackets and drive attachments), an air diverter valve, a check valve, an air pipe assembly, and connection hoses. Inspection Accelerate engine to approximately 1500 R P M and observe air flow from hose(s). If air flow increases as engine is accelerated, pump is operating satisfactorily. If air flow does not increase or is not present, proceed as follows: 1. Check for proper drive belt tension. The A IR system is not completely noiseless. Under normal conditions, noise rises in pitch as engine speed increases. To determine if excessive noise is the fault of the system, operate the engine with the pump drive belt removed. If excessive noise does not exist with the belt removed, proceed as follows: 2. Check for a seized Air Injection Pump Do not oil pump. LIGHT TRUCK SERVICE MANUAL 6E-16 ENGINE EMISSION CONTROLS 3. Check hoses, pipes and all connections for leaks and proper routing. 4. Check diverter valve attaching screws for tighteness. 5. Check injection pump for proper mounting and bolt torque. 6. Repair irregularities in these components as necessary. 7. If no irregularities exist and the air injection pump noise is still excessive, remove and replace pump. Air Pump Drive Belt Adjustment and Replacement 1. Inspect drive belt for wear, cracks or deterioration. 2. Loosen generator adjustment bolt on V8 models or pump bolt on L6 models. 3. Replace belt if required. 4. Move generator or pump until drive belt is at proper tension as specificed in Section 6B, then retighten bolts. 5. Check belt tension using a belt tension gage. Air Pump Pulley Replacem ent 1. Hold pump pulley from turning by compressing drive belt, then loosen pump pulley bolts (Fig. 6E-21 and 22 ). 2. Loosen pump through bolt and adjusting bolt. 3. Remove drive belt, pump pulley and pulley spacer. 4. Install pump, pulley and spacer with retaining bolts hand tight. 5. Install drive belt and adjust to proper tension as specified in Section 6B. 6. Hold pump pulley from turning by compressing drive belt, then torque pump pulley bolts to 32 N-m (24 ft. lbs.). 7. Recheck belt tension and adjust if required. Air Pump Filter Fan R eplacem ent Before starting this operation note the following: • Do not allow any fragments to enter the air pump intake hole. Air Injection Pump Removal 1. Disconnect battery cable. 2. Mark front of pump pulley so it can be installed in the same direction. 3. Remove air pump pulley as outlined under air pump pulley replacement. 4. Disconnect hoses, vacuum and electrical connections from diverter valve. 5. Remove air pump mounting bolts and remove pump assembly. 6. If pump is being replaced, transfer diverter valve to new pump. Install 1. Install air pump assembly and tighten mounting bolts. 2. Reconnect hoses, vacuum and electrical connections to diverter valve. 3. Install air pump pulley. 4. Install pump belt and adjust to correct tension. 5. Reconnect battery cable. 6. Check system for proper operation. LIGHT TRUCK SERVICE MANUAL • Do not remove filter fan by inserting a screwdriver between pump and filter fan. Air damage to sealing lip on pump will result. • Do not remove motor drive hub from filter fan. • It is seldom possible to remove the filter fan without destroying it. 1. Remove drive belt, pulley and spacer. 2. Insert needle nose pliers and pull filter fan from hub (Fig. 6E-23). 3. Position new filter fan on pump hub. 4. Position spacer and pump pulley against centrifugal filter fan. 5. Install pump pulley bolts and tighten equally to 9 N-m (30 in. lbs.). This will compress the centrifugal filter fan onto the pump hub (Fig. 6E-24). Do not drive filter fan on with a hammer. A slight amount of interference with the housing bore is normal. After a new filter fan has been installed, it may squeal upon initial operation or until O.D. sealing lip has worn in. This may require a short period of pump operation at various engine speeds. 6. Install pump drive belt and adjust to specifications shown in Section 6B. ENGINE EMISSION CONTROLS 6E-17 Fig. 6E-22--Air Pump and Pulley-L6 Air Hoses and Injection Pipes Inspection a n d R eplacem ent (Fig. 6E -25 an d 26) 1. I nspect all hoses for deterioration or holes. 2. Inspect all air injection pipes for cracks or holes. 3. Check all hose and pipe connections. 4. Check pipe and hose routing. Interference may cause wear. pressure side, the connection should be checked fo leaks with a soapy water solution. 6. If hose a n d /o r pipe replacem ent is required, note routing, then remove hose a nd/or those as required. 7. Install new hose and /o r pipe, routing them as when removed. 8. Tighten hose and pipe connections. Use an anti-seize compound on threads of the air pipe fitting when re­ assembling. 5. If a leak is suspected on the pressure side of the system or any pipe and/or hose has been disconnected on the s i, Fig. 6E-23— F ilte r Fan-Removal . Fig. 6E -2 4 --F ilte r F a n -lnstallatio n LIGHT TRUCK SERVICE MANUAL 6E-18 ENGINE EMISSION CONTROLS PIPE ASSY CHECK VALV EXTENSION PIPE ASSY EXTENSION Fig. 6E-25--Air Injection Pipes-L-6 Check Valve Air Diverter Valve Inspection Rem oval (Fig. 6E -27, 2 8 a n d 29 ) 1. The check valve should be inspected whenever the hose is disconnected from the check valve or whenever check valve failure is suspected. (A pump that had become inoperative and had shown indications of having exhaust gases in the pump would indicate check valve failure). 2. Blow through the check valve (toward the cylinder head) then attem pt to suck back through check valve. Flow should only be in one direction (toward the exhaust manifold). Replace valve which does not function this way. R eplacem ent (Fig. 6E -25 a n d 26 ) 1. Release clamp and disconnect air hoses from check valve. 2. Unscrew check valve from air injection pipe. 3. Screw check valve onto air injection pipe. 4. Position air hose on check valve and secure with clamp LIGHT TRUCK SERVICE MANUAL 1. 2. 3. 4. Disconnect battery ground cable. Disconnect vacuum hose at valve. Disconnect air outlet hoses from valve. Bend tab on locks and remove bolts holding elbow to control valve. 5. Remove control valve and gasket from elbow. Installation 1. 2. 3. 4. Install control valve and gasket to elbow. Install bolts and locks to elbow. Tighten bolts to elbow and control valve. Bend tab nearest to hex flat against the bolt and screw heads. 5. Connect vacuum and air outlet hoses to valve. 6. Reconnect battery ground cable. 7. Check system operation. ENGINE EMISSION CONTROLS 6E-19 Fig. 6E-26--Air Injection Pipes-V8 LIGHT TRUCK SERVICE MANUAL 6E-20 ENGINE EMISSION CONTROLS Fig. 6E-29~Diverter Valve G Series-V8 PULSE AIR INJECTION REACTOR SYSTEM • PAIR INSPECTION AND CHECKING PULSE AIR VALVE Deceleration Valve 4.1L (LE-3) Inspect pulse air valves, pipes, grommets and hose for leaks and cracks and replace as required. R eplacem ent Check operation of pulse air valves by creating a vacuum at grommet end of valve by adapting tool J-23738, with a tight fitting length of 3 /4 " hose. With vacuum of 5 kPa (17" Hg.) there will be an allowable drop to 1.7 kPa (6" Hg.) in 2 seconds. Replace valve and/or hose if vacuum drops in less than two seconds. Vacuum drop must be a result of a leaking valve not a leaking hose or connection. NOTICE: Replacement of Pulse Air Valve (Fig. 6E-30) 1. Remove air cleaner and disconnect rubber hose from plenum connecting pipe. 2. Disconnect four pipe check valve fittings at cylinder head and remove check valve pipes from plenum grommets. 3. Disconnect check valve from check valve pipe. 4. Bench assemble check valves to check valve pipe. 5. Install pipe check valve assemblies to cylinder head as shown in fig. 6E-34 and finger tighten the fittings. 6. Using a 1 " open end wrench or similar tool as a lever, align check valve on pipe " A " (fig. 6E-31) to the plenum grommet. Then using palm of your left hand install check valve into the grommet. Use rubber lubricant on grommets to ease assembly. 7. Repeat procedure in step 6 on pipe "B " (fig. 6E-32) but use your left hand on the tool for alignment of check valve and install valve with the palm of your right hand. 8. Tighten fittings to specified torque and reinstall air cleaner and hose. LIGHT TRUCK SERVICE MANUAL 1. Remove vacuum hoses from valve (Fig. 6E-33). 2. Remove two screws securing valve to engine bracket and remove valve. 3. Install valve, tighten screws to engine bracket. 4. Install vacuum hoses. THERMOSTATIC AIR CLEANER (THERMAC) Checking Thermae Air Cleaner 1. Inspect system to be sure all hoses and charts are connected (Fig. 6E-34 and 35). Check for kinked, plugged or deteriorated hoses. 2. If engine is warm above 27°C (80°F), remove air cleaner. Allow it to cool to room temperature, below 27°C (80°F). Placing a cool wet rag on the temperature sensor will aid in cooling. 3. Install cooled air cleaner with cold air intake discon­ nected from snorkel (if equipped). 4. Observe damper door before starting the engine. It should be in the open snorkel position (hot air duct covered). 5. S ta r t engine. W atch d am p e r door in air cleaner snorkel. When engine is first started, damper door should close. As air cleaner warms up, damper door should open slowly. 6. If d am per door does not close when the engine is started, remove air cleaner. 7. Apply at least 23 kPa (7 in. Hg.) of vacuum to the vacuum diaphragm motor through hose disconnected at the temperature sensor. Damper door should com­ pletely block off snorkel passage when vacuum is applied. If not check to see if linkage is hooked up correctly. ENGINE EMISSION CONTROLS 6E-21 PLENUM PIPE HOSE A fR C LEAN ER PLENUM PIP GROMMETS CHECK V A L V E ASM. TORQUE TO 23 N-m (17 FT. LBS.) PLENUM 'A ' PIPE ASM. EXTENSIO N TUBES 'B ' PIPE ASM. 'A ' PIPE ASM. TORQUE TO 38 N m (28 FT. LBS.) PLENUM CONNECTING PIPE Fig. 6E-30--PAIR System Fig. 6E-31--PAIR (Pipe A) LIGHT TRUCK SERVICE MANUAL 6E-22 ENGINE EMISSION CONTROLS Fig. 6E-32--PAIR (Pipe B) 8. With vacuum still applied, trap vacuum in vacuum diap hrag m motor by bending hose. D am per door should remain closed; if not, replace vacuum dia­ phragm motor assembly. (Failure of th vacuum dia­ phragm motor assembly is more likely to be caused from binding linkage or a corroded snorkel than from a failed diaphragm. This should be checked first, before replacing the diaphragm.) 9. Reinstall air cleaner. As the engine warms up, the dam p er door should s ta rt to allow outside air and heated air toenter the carburetor. 10. If the air cleaner fails to operate as described above or if correct operation of the air cleaner is still in doubt, perform thermometer check of sensor. Thermometer Check of Sensor 1. S tart test with air cleaner temperature below 80°F (27°C). If engine has been run recently, remove air cleaner and place a cool wet rag on sensor. Remove air cleaner cover and place T h e rm o m e te r as close as possible to the sensor. Let air cleaner cool until thermometer reads below 79°F (26°C) about 5 to 10 minutes. Reinstall air cleaner on engine and continue to step 2 below. 2. S tart and idle engine. Damper door should move to close the snorkel passage immediately if engine is cool enough. When damper door starts to open the snorkel passage (in a few minutes), remove air cleaner cover and reaethermometer. It must read 100°F.-(-20oF. (38°C 7°C). 3. If the damper door does not start to open up the snorkel passage at temperature indicated, tem perature sensor if malfunctioning and must be replaced. AIR CLEANER TVS Remove 1. 2. 3. 4. 5. Remove air cleaner cover and element. Disconnect vacuum hoses. Pry clip from TVS and remove. Install new TVS and replace clip. Reconnect vacuum hoses (refer to Vehicle Emission Control Information Label). 6. Install air cleaner element and cover. Air Cleaner Element Replacement Paper Elem ent 1. Remove air cleaner cover. LIGHT TRUCK SERVICE MANUAL ENGINE EMISSION CONTROLS 6E-23 Fig. 6 E -3 4 --T h e rm a c A ir C le a n e r-T y p ic a l 2. Remove element. Vacuum Diaphragm Motor 3. Install new element in air cleaner with either end up. Rem oval (Fig. 6E -37) 4. Install air cleaner cover. Do not over tighten wing nut. P o lyw rap Elem ent (P M odels) 1. Remove air cleaner cover. 2. Remove element. 3. Remove poly wrap band from paper element and dis­ card element (Fig. 6E-36). 4. Clean bottom section of air cleaner and inspect cover seal for tears or cracks. Replace seal if damaged. 5. Inspect band for tears and replace if damaged. 6.- If band is serviceable, wash in kerosene or mineral spirits and squeeze out excess solvent. NOTICE: Never use a hot degreaser or any solvent containing acetone or similar solvent; also, never shake, swing or wring the element to remove excess solvent as this may tear the polyurethane m aterial. Instead, "squeeze" the excess solvent from the element. 7. Dip band into light engine oil and squeeze out excess oil. 8. Install band around outer surface of new paper element. 9. Install element in bottom section of air cleaner with either end up. 10. Install air cleaner cover. Do not over-torque wing nut(s). 1. Remove air cleaner. 2. Disconnect vacuum hose from motor. 3. Drill out the two spot welds initially with a 1/16" hole, then enlarge as required to remove the retaining strap. Do not damage the snorkel tube. 4. Remove motor retaining strap. 5. Lift up motor, cocking it to one side to unhook the motor linkage at the control damper assembly. Installation 1. Drill a 7 /6 4 " hole in snorkel tube at center of vacuum motor retaining strap. 2. Insert vacuum motor linkage into control dam p er assembly. 3. Use the motor retaining strap and sheet metal screw provided in the motor service package to secure the retaining strap and motor to the snorkel tube. 4. M ake sure the screw does not interfere with the operation of the damper assembly. Shorten screw if required. 5. Connect vacuum hose to motor and install air cleaner. Temperature Sensor Removal 1. Remove air cleaner. 2. Detach hoses at sensor. LIGHT TRUCK SERVICE MANUAL 6E-24 ENGINE EMISSION CONTROLS TEMPERATURE SENSOR* VACUUM DIAPHRAGM MOTOR AIR BLEED VALVE CLOSED DIAPHRAGM SNORKEL HOT AIR DELIVERY MODE VACUUM HOSES INLET- DIAPHRAGM DAMPER DOOR HOT AIR DUCT HOT AIR TEMPERATURE SENSOR B MOTOR REGULATING MOD E Fig. 6E-35--Preheated A ir System O peration 3. Pry up tabs on sensor retaining clip: remove clip and sensor from air cleaner. Note position of sensor for installation. Installation 1. Install sensor and gasket assembly in original position. 2. Press retainer clip on hose connectors. 3. Connect vacuum hoses and install air cleaner on engine THROTTLE RETURN CONTROL (TRC) SYSTEM Checking And Adjusting TRC System Check hoses for cracking, abrasion, or deterioration and replace as necessary. Check for shorted or broken wires and ensure that electrical connectors are fully engaged at the distributor, speed switch and vacuum solenoid. Check system function for proper operation and adjust as necessary. 1. Connect precision tachometer (capable of resolving 10 R P M ) to the distributor " T A C H " terminal. 2. Start engine and advance throttle to indicated 1890 RPM . Throttle lever actuator should be extended at this speed. LIGHT TRUCK SERVICE MANUAL 3. Reduce throttle opening to indicated 1700 R P M . T hrottle lever actuato r should be retracted at this speed. 4. If the throttle lever actuator operates outside of the 1700 to 1890 RPM limits, the speed switch is out of calibration and should be replaced. 5. If the actuator does not operate at any speed, proceed with the following steps. a. With a voltmeter, check for voltage at the vacuum solenoid and speed switch. This is accomplished by connecting the negative probe of the voltmeter to the engine "ground" and inserting the positive probe in the connector cavity of the voltage source wire. A voltage of 12-14 volts should be measured at this term inal on both the solenoid and speed switch. When making this measurement, it is not necessary to unplug the connector from its component. The voltmeter probe can be inserted in the connector body on the wire side of the connector to contact the metal terminal. b. If voltage is present at one device and not the other, repair the engine wiring harness as required. ENGINE EMISSION CONTROLS 6E-25 f. If the a c tu ato r extends in Step D, ground the solenoid-to-switch wire terminal at the speed switch. If it does not extend, repair the wire connecting the speed switch and solenoid. If it does extend, check the speed switch ground wire for " g ro u n d " - it should read 0 volts when checked with a voltmeter with the engine running; check the speed switch-todistributor wire for proper connection. W ith both the ground and distributor wires properly connected and if the actuator does not extend when operating above 1890 RPM , replace the speed switch. 6. If the actuator remains extended at all speeds, proceed as with following steps. a. Remove connector from vacuum solenoid. b. If actuator remains extended, check the orifice in the solenoid side port for plugging. If plugged, clear and reconnect system and recheck. If the actuator again remains extended, remove the solenoid connector. If the actuator does not retract, replace the vacuum solenoid. c. If the actuator retracts with the solenoid connector off, reconnect and then remove the speed switch connector. If the actuator retracts, replace the speed switch. If the actuator does not retract, the solenoidto-switch wire is shorted to ground in the wiring harness. Repair as required. c. If voltage is not present at either device, check the engine harness connections at the distributor a nd/or bulkhead connector. Repair as required. d. If the proper voltage exists at each device, to check for proper solenoid valve operation "ground" the solenoid-to-switch connecting wire terminal at the solenoid connector using a jum per wire. The throttle lever actuator should extend (engine running). e. If it does not extend, remove the hose from the solenoid side port that connects to the actuator hose. Visually check the orifice in this port for plugging. Clear the orifice as required. If not plugged, replace the solenoid. DRILL 7 /6 4 " HOLE IN CENTER POSITION OF STRAP SPOTWELDS VACUUM DIAPHRAGM MOTOR RETAINING STRAP INSTALL REPLACEMENT SENSOR ASSM. IN SAME POSITION AS ORIGINAL ASSMJ Fig. 6E-37--Vacuum M o to r Throttle Lever Actuator - Checking Procedure 1. Disconnect valve to actuator hose at valve and connect to an external vacuum source equipped with a vacuum gage. 2. Apply 20 in. Hg vacuum to the actuator and seal off the vacuum source. If the vacuum gage reading drops, then the actuator is leaking and must be replaced. 3. To check the actuator for proper operation: a. Check the throttle lever, shaft, and linkage to be sure that they operate freely without binding or sticking. b. S tart engine and run until warmed up and idle is stable. Note idle rpm. c. Apply 20 in. Hg vacuum to the actuator. Manually open the throttle slightly and allow to close against the extended actuator plunger. Note the engine rpm. d. Release and reapply 20 in. Hg vacuum to the actuator and note the rpm to which the engine speed increases (do not assist the actuator). e. If the rpm obtained in step D is not within 150 rpm of that obtained in step C, then the actuator plunger may be binding due to dirt, corrosion, varnish, etc., or the actuator diaphragm may be too weak. If binding is not indicated or cannot be corrected then the actuator must be replaced. f. Release the vacuum from the a c tu a to r and the engine speed should return to within 50 rpm of the idle speed noted in step 2. If it does not, the plunger may be binding due to dirt, corrosion, varnish, etc. If the problem cannot be corrected, the actuator must be replaced. g. If the engine rpm noted in step 3 is not within the specified T R C speed range, the T R C actuator must be adjusted. See Throttle Lever A ctuator Adjusting Procedure in section 6C. LIGHT TRUCK SERVICE MANUAL 6E-26 ENGINE EMISSION CONTROLS THROTTLE RETURN CONTROL SYSTEM C AR BU R E TO R (T Y P IC A L ) EX TE N D E D POSITION (WHEN V A C U U M IS AP PLIED ) P R IM A R Y T H R O T T L E LEVER T H R O T T L E LEVER ACTUATOR / M A N IF O L D V A C U U M (V A L V E OPEN O N L Y ) ELECTRONIC SPEED SENSO V E N T TO ATM OSPHERE \ SO LE N O ID VACUUM C O N TR O L VALVE E N G INE SPEED— S IG N A L FROM D IS T R IB U T O R Fig. 6E-39--Throttle Return Control System VACUUM ADVANCE CONTROL Trapped Vacuum Spark Trapped vacuum spark is on all engines. A thermal vacuum switch (T V S) is used to sense engine coolant temperature. A check valve is between manifold vacuum, distributor and thermal vacuum switch. HOSE T R C S O L E N O ID CONTROL V A L V E ASM. When engine temperature is below specified value, the manifold vacuum signal is routed through the check valve to the distributor. Ports on TVS are blocked. The check valve will keep the vacuum to the distributor at vacuum levels higher than manifold depression during vehicle accelera­ tion. A small sintered iron bleed orifice is provided in the check valve to allow for a leak-down to enable restarts in case of engine stalls. T H R O T T L E LE V E R A C T U A T O R TRC S O LE N O ID CO NTRO L V A L V E ASM. THRO TTLE V A LV E ACTUATOR ENG INE STUD A C C E LE R A T O R SUPPORT HOSE Fig. 6E-40--Throttle Valve (L6) VACUUM F IT T IN G Fig. 6E-41--Throttle Valve (V8) LIGHT TRUCK SERVICE MANUAL I ENGINE EMISSION CONTROLS When engine temperature is above specified value, the ports on TVS will be open to allow manifold vacuum to the distributor. The check valve in this mode of operation acts as a connector. SPARK VACUUM DELAY 6E-27 Electronic Spark Control system. It mounts on the right hand side of engine in block drain hole. Upon replacement, avoid the use of impact type tools and excessive torque. • Minimum torque 16.3 N-m (12.02 ft. lbs.) • Maximum torque 21.7 N-m (16.01 ft. lbs.) General Description On heavy duty emission engines a check valve with an internal beed is installed between the Trapped Vacuum S park check valve and the distributor. W hen manifold vacuum increases it opens the check valve which allows the distributor vacuum to increase to the same level. Decreasing manifold vacuum, as during vehicle acceleration; closes the check valve and the distributor vacuum will decrease at a rate controlled by the internal bleed. DETONATION SENSOR Replacement The Detonation Sensor is an integral part of the VEHICLE EMISSION CONTROL INFORMATION LABEL The Vehicle Emission Control Information Label (Fig. 6E-42) is located in the engine compartment (fan shroud, radiator support, hood underside, etc.) of every vehicle produced by General Motors Corporation. The label con­ tains important emission specifications and setting proce­ dures, as well as a vacuum hose schematic with emission components identified. When servicing the engine or emission systems, the Vehicle Emission Control Inform ation Label should be checked for up-to-date information. LIGHT TRUCK SERVICE MANUAL 6E-28 AD JU STM EN T PROCEDURE S O I. H R r 181 4 mAN A 1040 8 CATALYST RMATION 0 G C N ER A l M O TO R S (O R P O P , E N G IN E A D J U S T M E N T S P E C IF IC A T IO N S TRANSMISSION TIMING (“BTC (a> R P M I M * * ( A l l ADJUSTMENTS WITH ENGINE AT NORMAL OPERATING TEMPERATURE HSTALLED. AMO A M CONDITIONING OH . EXCEPT WHIRS NOTiD CHOKE FULL OPEN. AM CLEANER E M IS S IO N HO SC R O U T IN S r W HERE 1 EQUIPPE AIK flPEGR/UC IO W AlTITUOE ( ERIIFKATION S IT P A R K IN G B K A K l A N D H O C K D K IV t W M fflS AAR ?• CONTROLS Fig. 6E-42--Vehicle VEHICLE EMISSION CONTROL AAR ENGINE EMISSION LABEL CODE E N G IN E S IZ E E X H A U S T E M IS S IO N F A M IL Y E V A P O R A T IV E E M IS S IO N F A M IL Y A IR CLEANER 700 (N) SPARK PlUG GAP (IN ) IDLE SPEED SCREW IR P M ) Emission Control Information (SOLENOIO INACTIVE) I DISTRIBUTOR DISC ON NIC T AND PlUG VACUUM HOSE AT DISTRIBUTOR ? O i l SP IE D SCREW SPECIFIED ENGINI SP IE D SIT IGNITION TIM ING AT IDLE SPEED SOLENOID (R PM ) UNPLUG ANO RICONNICT VACUUM HOSi TO DISTRIBUTOR (SOLENOID ACTIVE) DISCONNECT ELECTRICAL IEAD (ROM KHE SOLENOIO * EQUIPPED CARBURETOR IDIE SPEED SCREW TO S P K I M D SPIED 3 IDtE SPEED SOEENOID II I EQUIPPEO) RECONNICT IEAD TO SOEENOIO OPEN THROTTLE MOMENTARILY TO ASSURE SOLENOID ADJUST SOLENOIO TO SPECIfKO SPIED FAST IDEE SPEED SCREW FAST IDEE S P IE D SCREW (R P M i DISCONNECT IIIC TR IC A i IE AD EROM AIR CONDITIONING COM PRESSOR ANO TURN A/C SWITCH ON IS FULLY EXTENDED TURN A/C OIF ADJUST RECONNECT COMPRESSOR LEAD ANO f N O T! ] MXE MIXTURE SCRIW S A M PRESET ANO SEAL 10 AT FACTORY PROVISION FOR ADJUSTMENT DURING TUNC UP IS NOT PROVIDED WITH ENGINE O ff. PLACE THROTTLE ON HIGH STEP OE FAST IDEE C A M DISCONNfCT ANO P lU G V AC U UM HOSE AT EGR VALVE START ENGINE WITHOUT TOUCHING THROTTLE ADJUST TO SPICIFIED SPEED OPEN THROTTLE TO RELEASE FAST IDEE C A M UNPLUG ANO RECONNECT VACU UM HOSE TO EGR V A lV f THIS V IH IC ll CONFORMS TO U S STOP ENGINE. SEE SERVICE M ANUAL. MAMTENANCE SCHEDULE I ANO EM ISSIO N HOSE ROUTING DIAG RA M FOR ADDITIONAL INFORMATION EPA REGULATIONS APPLICABLE TO 1911 MODEL YEAR NEW LIGHT DUTY TRUCKS P I NO 14076117 Label LABEL PART NUMBER E M IS S IO N C O M P O N E N T A N D V A C U U M H O S E S C H E M A T IC ENGINE EXHAUST SYSTEM 6F-1 SECTION 6F ENGINE E X H A U S T S Y S T E M G E N E R A L D E SC R IP T IO N The Exhaust System is suspended by hangers attached to the frame members (Figs. 6F-3 & 6F-4). Annoying rattles and noise vibrations in the Exhaust Sys­ tem are usually caused by misalignment of parts. When align­ ing the system, leave all bolts or nuts loose until all parts are properly aligned, then tighten, working from front to rear. When replacing a muffler, the tailpipe(s) should also be replaced. Sealer such as #1051249, or equivalent, should be used at all clamped joint connections. 'ssntsjm oaskjafr • j ju CATALYTIC CONVERTER The catalytic converter is an emission control device added to the exhaust system to reduce hydrocarbon and car­ bon monoxide pollutants from the exhaust gas stream (Figs. 6F-1 & 6F-2). THE CATALYTIC CONVERTER REQUIRES THE USE OF UNLEADED FUEL ONLY. Periodic maintenance of the exhaust system is not re­ quired; however, if the vehicle is raised for other service, it is advisable to check the general condition of the catalytic con­ verter, pipes and muffler(s). The catalyst in monolith converters is not serviceable. The catalyst in bead type converters can be replaced, on vehicle, using tool # J-29132 or off vehicle by removing the converter or the exhaust system. m CO NVERT ER SHELL CONVERTER SHELL MONOLITH Fig. 6F-1 — M onolith Converter Fig. 6F-2 — Underfloor Converter LIGHT TR U C K SER V IC E M A N U A L 6F-2 ENGINE EXHAUST SYSTEM CONDITION Leaking E xh a u st Gases POSSIBLE CAUSE Leaks at pipe joints. CORRECTION Tighten U -b o lt nuts at leaking joints to 30 lb. ft. (40 N - m ) . Dam aged or im properly Replace seals or packing installed seals or packing. as necessary. Loose exhaust pipe heat tube Replace seals or p acking as required. T ighten stud nuts or bolts to specifications. extension connections. Burned or rusted ou t exhaust Replace heat tube extensions pipe heat tube extensions. as required. Tighten c lam ps at leaking E xh aust Noises Leaks at m anifold or pipe connections. con ne ctions to specified torque. R eplace gasket or packing as required. Burned or blow n out m uffler. Replace m uffler assembly. Burned or rusted out exhaust pipe. Replace exhaust pipe. Exhaust pipe leaking at m an ifold flange. Tighten attaching bolts nuts to 17 lb. ft. (23 N -m ) E xh a u st m anifold cracked or broken. Replace m an ifold. Leak between m anifold and cylinder head. Tighten m a n ifold to cylinder head stud nuts or bo lts to specifications. Loss o f engine pow er and/or Dislodge d turn in g tubes and or internal rattles in m uffler. baffles in m uffler. Lo ss of engine power. Im p lo d in g (inner wall collapse) Replace m uffler. Replace exhaust pipe. of exhaust pipe (except" P " T ru ck ) LIGHT T R U C K SE R V IC E M A N U A L ENGINE EXHAUST SYSTEM 6F-3 ON-VEHICLE S E R V IC E Fig. 6F-3 — Catalytic Converter - CK Series CATALYST (Figs. 6F-3 & 6F-4) Removal (Off Vehicle) 1. Raise vehicle. 2. Remove converter. 3. Remove converter pressed fill plug by driving a small chisel between the converter shell and the fill plug (Fig. 6F-5). Continue to deform fill plug until it can be removed with pliers (Fig. 6F-6). NOTICE: Do not pry fill plug from converter as damage to fill plug sealing surface could result. 4. Holding converter over a container, empty catalyst from converter by shaking until all beads are removed. Installation (Off Vehicle) 1. Raise front of converter to approximately 45° and fill with approved new catalyst. Filling can be accomplished by tapping on converter belt (Fig. 6F-7) with a hammer, 90° to the converter, while pouring beads into the converter thru the fill plug hole. Continue tapping and pouring until converter is full. Not all beads will be able to be installed. 2. Install service fill plug (Fig. 6F-8) as follows: Install the bolt into the bridge and put the bridge into the converter opening. Move bolt back and forth to loosen catalyst beads until bridge is positioned as shown in Fig. 6F-9. 3. Remove bolt from bridge then put the washer and fill plug, dished side out, over the bolt. 4. While holding the fill plug and washer against the bolt head (Fig. 6F-10), thread the bolt 4 or 5 turns into the bridge. LIGHT TR U C K SE R V IC E M A N U A L 6F-4 ENGINE EXHAUST SYSTEM BOTTOM COVER REPLACEMENT Fig. 6F-5 — R em o vin g Pressed Plug 5. (28 lb. 6. 7. After the fill plug is seated, tighten the bolt to 38 N-m ft.). Install converter. Start engine and check for leaks. BOTTOM COVER 1. Remove bottom cover by cutting close to the bottom outside edge, Fig. 6F-11. Do not remove the fill plug. The depth of the cut must be very shallow to prevent damage to the inner shell of the converter. 2. Remove insulation. 3. Inspect inner shell of the converter for damage. If there is damage in the inner shell, the converter assembly must be replaced. 4. Place new insulation in the replacement cover (Fig. 6F-12). Apply sealing compound, #8998245 or equivalent, all around the cover after the insulation is in position. Apply extra sealer at the front and rear opening for the pipes (Fig. 6F-13). If, for any reason, the bottom cover of the converter is torn or damaged, it can be replaced with a repair kit. BRIDGE Fig. 6F-8 — Service Fill Plug LIGHT TR U C K SE R V IC E M A N U A L ENGINE EXHAUST SYSTEM 6F-5 Fig. 6F-11 — R em o vin g Bottom Cover Fig. 6F-9 — Positioning Fill Plug Bridge 5. Install replacement cover on converter (Fig. 6F-14). 6. Install cover retaining channels on both sides of the converter (Fig. 6F-15). 7. Attach 2 clamps over retaining channels at each end of the converter (Fig. 6F-16). Fig. 6F-12 — Catalytic Converter Insulation Fig. 6F-10 — Installing Fill Plug Fig. 6F-13 — Catalytic Converter Inner Shell LIGHT TR U C K SE R V IC E M A N U A L 6F-6 ENGINE EXHAUST SYSTEM Fig. 6F-14 — Installing Bottom Cover Replacement Fig. 6F-15 — Installing Bottom Cover Retaining Channels LIGHT T R U C K SE R V IC E M A N U A L ENGINE PERFORMANCE SPECIFICATIONS 6G-1 SECTION 6G ENGINE PERFORMANCE SPECIFICATIONS T H E F O L L O W IN G C H A R T R E P R E S E N T S T H E L A T E ST C E R ­ T IF IE D IN F O R M A T IO N A V A IL A B L E AT T IM E O F P R IN T IN G . A L W A Y S R E F E R TO T H E V E H IC L E E M IS S IO N C O N T R O L IN ­ F O R M A T IO N LABEL FO R THE M O ST U P -T O -D A T E IN F O R M A T IO N . LIGHT DUTY TRUCK ENGINE PERFORMANCE SPECIFICATION CHART DISTRIBUTOR ENGINE AND E M IS S IO N FAMILY EM ISSIO N LABEL CODE IGNITION T IM IN G B.T.D.C. DEGREES SPARK PLUG TYPE & GAP 10° R45TS (.035) SOLENOID SCREW (RPM) CURB IDLE (RPM) FAST IDLE (RPM) 4501N) 750(N) 2000(N) 4.1 L (250 C.I.D.) LE3 FAMILY 18F2HANQR MANUAL TRANS. FEDERAL SALES C-10 ACR ACS 4.1 L (250 C.I.D.) LE3 FAMILY 18F2HANQR MANUAL TRANS. FEDERAL SALES K-10 ACR ACS 4.1L (250 C.I.D.) LE3 FAMILY 18F2HANQR MANUAL TRANS. FEDERAL SALES G10.20 ACS ADA 10° R46TS (.035) 450 (N) 4.1 L (250 C.I.D.) LE3 FAMILY 18F2HHNR MANUAL TRANS CALIF. SALES C-10 ACW AWA ACK AWB 10° R46TS (.035) 450 (N) 4.1L (250 C.I.D.) LE3 FAMILY 18F2HHNR MANUAL TRANS. CALIF. & FED. SALES G-10, G20, G30 ACX ADB AFA 10° R46TS (035) 4.1 L (250 C.I.D.) LE3 FAMILY 18F2HANQR AUTO TRANS. FEDERAL SALES C-10, 20 K-10 ACT AUU ACU 10° 4.1 L (250 C.I.D.) LE3 FAMILY 18F2HANQR AUTO TRANS. FEDERAL SALES G-10, 20 ADC AAC DIST. MODEL VACUUM MODEL 17081621 1110589 644 17081629 ‘ ill 1388 691 CARBURETOR PART NUM BER VA CUUM & MEC H A N ICA L ADVANCE MECH AN ICAL VACUUM ADVANCE ADVANCE (Crank (In Crank Degrees Degrees @ @ Inches Engine RPM ) of Vacuum) 0° @3" 16° @ 6.5" 0“ @ 3" 20° @ 7.5" 0° @ 1100 14° @ 2300 24° @ 4100 17081625 1110590 665 17081633 1110753 626 2000 (N) 17081623 17081627 1110589 644 0° @ 3" 16° @ 6.5" 0°@ 1100 14° @ 2300 24° @ 4100 750 (N) 2000 (N) 17081721 1110749 626 0° @ 4" 10° @ 8" 0° @ 1100 7° @ 2300 16° @ 4200 450 (N| 750 (N) 2000 (N) 17081727 G10 17081725 G20, 30 1110749 626 0° @ 4" 10° @ 8" 0° @ 1100 7° @ 2300 16° @ 4200 R46TS (.035) 450 (D) 650 (D) 2200 (P or N) 17081622 1110589 644 0° @ 3" 16° @ 6.5" 0° @ 1100 14° @ 2300 24° @ 4100 8° R46TS (.035) 450(D) 650 ID) 700 (D) AAC 2200 (P or N) 17081624 17081626 1110589 644 0° @ 3" 16° @ 6.5" 0° @ 1100 14° @ 2300 24° @ 4100 ACY AWC ACZ AWD 10° R46TS (.035) 450 (D| 650 (D) 2200 (P or N) 17081720 1110749 626 0° @ 4" 10° @ 8" 0° @ 1100 7° @ 2300 16° @ 4200 4.1 L (250 C.I.D.) LE3 FAMILY 18F2HHNR AUTO TRANS. CALIF. & FED. SALES G10, 20, 30 ACZ ADD AFB 10° R46TS (.035) 450 (D) 650 (0) 2200 IP or N) 17081726 1110749 626 0° @ 4" 10° @ 8" 0° @ 1100 7° @ 2300 16° @ 4200 4.8 L (292 C.I.D.) L25 FAMILY GM 112 MANUAL TRANS. NATION WIDE CK20, 30; P20, 30 ADF ADM ADH 8° R44T (.035) 4501N) 7001N) 2400(N) 17081309 17081680 1110753 626 0° @ 4" 10° @ 8" 0° @ 1100 14° @ 2300 24° @4100 4.1 L (250 C.I.D.) LE3 FAMILY 18F2HHNR AUTO TRANS. CALIF. SALES C-10 ‘ THROTTLE RETURN CONTROL SPEED 1500 RPM 10° R46TS (.035) 750 (N) 450 (N) _• Fig. t r - 6 1 2000 (N) 750 (N) LABEL 800 (N) ADA n • n r -f 0° @ 4" 15° @ 10" 1 0° @ 1100 14° @ 2300 24° @ 4100 *• G - 1 --Engine Perform ance Specifications LIG H T T R U C K SERVICE M A N U A L 6G-2 ENGINE PERFORMANCE SPECIFICATIONS LIGHT DUTY TRUCK ENGINE PERFORMANCE SPECIFICATION CHART DISTRIBUTOR ENGINE AND EMISSION FAMILY IGNITION TIMING B.T.D.C. DEGREES EMISSION LABEL CODE SPARK PLUG TYPE & GAP SOLENOID SCREW (RPM) CURB IOLE (RPM) FAST IDLE (RPM) CARBURETOR PART NUMBER DIST. MODEL VACUUM MODEL VACUUM & MECHANICAL ADVANCE VACUUM ADVANCE MECHANICAL (In Crank Degrees ADVANCE (Crank @ Inches Degrees @ of Vacuum) Engine RPM) 8° R44T . (.035) 450 (N) 700 (N) 2400 (N) 17081309 17081680 1110753 626 0° @ 4" 10° @ 8" 0C @ 1100 14c @ 2300 24° @ 4100 8° R45TS (.045) 700 (N) 600 (N) 1300 (N) 17081143 17081145 w/AC 1103381 691 0° @ 3" 1 0 ° 7 .5 " 0° @ 1200 8° @ 2000 20° @ 4200 AAA 8C R45TS (.045) 700 (N) 600 (N) 1300 (N) 17081101 17081103 w/AC 1103369 644 0° @ 3*' 16° @ 6.5" 0° @ 1200 8° @ 2000 20° @ 4200 5.0L (305 C.I.D.) LG9 FAMILY 18Y2HAN AUTO TRANS FEDERAL SALES CIO; G10, 20 AAB 8° R45TS (.045) 600 (D) 500 (D) 1600 (P or N) 17081142 17081144 w/AC 1103381 691 0° @ 3" 10° @ 7.5" 0° @ 1200 8° @ 2000 20° @ 4200 5.0L (305 C.I.D.) LE9 FAMILY 18Y4HAN MANUAL TRANS FEDERAL SALES C-10 AAF 4° R45TS (0.45) 700 (N) 1300 INI 17081201 1103464 Elect Spark Control 5.0L (305 C.I.D.) LE9 FAMILY 18L4HANA MANUAL TRANS. FEDERAL SALES CIO. 20; K10 AAM AAR 4C R45TS (0.45) 700 (N) 1300 (N) 17081220 1103464 Elect Spark Control 5.0L (305 C.I.D.) LE9 FAMILY 18L4HANA MANUAL TRANS. FEDERAL SALES C-10 AUS 4° . R45TS (.045) 600 (N) 1500 (N) 17081200 1103465 Elect Spark Control 5.0L (305 C.I.D.) LE9 FAMILY 18L4HANA MANUAL TRANS. FEDERAL SALES G10, 20 AAJ 6C R45TS (.045) 700 (N) 1300 (N) 17081220 1103464 Elect Spark Control 5.0L (305 C.I.D.) LE9 FAMILY 18Y4HANA AUTO TRANS. FEDERAL SALES C-10 AAH 4C R45TS (045) 500 (D) 1600 (PI or (N) 17081206 w/AC 17081205 1103464 Elect Spark Control 5.0L (3.05 C.I.D.) LE9 FAMILY 18Y4HANA AUTO TRANS. FEDERAL SALES C-10. 20: K-10 AAN 6° R45TS (.045) 500 (D) 1600 (P) or 17081227 17081226 w/AC 1103464 Elect Spark Control 4.8L 1292 C I D.) L25 FAMILY GM112 AUTO TRANS NATION WIDE SALES CKP20, 30 ADF ADM ADH 5.0L (305 C I D.) LG9 FAMILY 18Y2HAN MANUAL TRANS. FEDERAL SALES C-10 AAA 5 0L (305 C I D.) LG9 FAMILY 18Y2HAN MANUAL TRANS FEDERAL SALES G10, 20 'r 026 , ' , AAS 2° 'THROTTLE RETURN CONTROL SPEED 1500 RPM LIGHT DUTY TRUCK ENGINE PERFORM ANCE SPECIFICATION CHART DISTRIBUTOR SPARK PLUG TYPE & GAP 5.0L (305 C.I.D.) LE9 FAMILY 18L4HANA AUTO TRANS. FEDERAL SALES G10, 20 AAK 4° R45TS (.045) 5.0L (305 C.I.D.) LF3 FAMILY 18L4HHNA AUTO TRANS. CALIF. SALES C-10 ACC AWF ACD ACF 8° R45TS (.045) 5.7L (350 C.I.D.) LS9 FAMILY 18L4HANA MANUAL TRANS. FEDERAL SALES C-10; K-10, 20 AAT 8° 5.7L (350 C.I.D.) LS9 FAMILY 18L4HANA MANUAL TRANS. FEDERAL SALES G-10, 20 AAW 5.7L (350 C.I.D.) LS9 FAMILY 18L4HANA AUTO TRANS. FEDERAL SALES C-10, K-10, 20 SOLENOID SCREW (RPM) VACUUM & MECHANICAL ADVANCE MECHANICAL ADVANCE (Crank Degrees @ Engine RPM) FAST IDLE (RPM) CARBURETOR PART NUMBER DIST. MODEL VACUUM MODEL 500 (D) 1600 (P) or (N) 17081227 17081226 w/AC 1103464 Elect Spark Control 550(D) 1800 (P) or (N) 17081526 w/AC 17081524 1103432 620 0° @ 4" 15° @ 12" 0° @ 1000 10° @ 2000 14° @ 4000 R45TS (.045) 700 (N) 1300(N) 17081291 1103353 624 0° @ 4" 20° @ 10 0° @ 12° @ 16° @ 22° @ 1100 1600 2400 4600 8° R45TS (.045) 700 (N) 1300(N) 17081291 1103353 624 0° @ 4" 20° @ 10 0° @ 12° @ 16° @ 22° @ 1100 1600 2400 4600 AAU 8° R45TS (.045) 600 (D) 500 (D) 1600' (P) or (N) 17081290 17081292 w/AC 1103353 624 0° @ 4" 20° @ 10" 5.7L (350 C.I.D.) LS9 FAMILY 18L4HANA AUTO TRANS. FEDERAL SALES G-10, 20 AAK 8° R45TS (.045) 600 (D) 500 (D) 1600 (P) or (N) 17081290 17081292 w/AC 1103353 624 0° @ 4" 20° @ 10" 0” @ 12” @ 16° @ 22° @ 1100 1600 2400 4600 5.7L (350 C.I.D.) LS9 FAMILY 18L4HHNA AUTO TRANS. CALIF. SALES CK-10 AAZ AAD 6° R45TS (.045) 650 (D) 550 (D) 1800 (P) or (N) 17081506 17081508 w/AC 1103433 620 0° @ 4" 15° @ 12" 0” @ 12“ @ 16° @ 22” @ 1100 1600 2400 4600 AAZ 6° R45TS (.045) 650 (D) 550 (D) 1600 (P or N) 17081506 17081508 w/AC 1103433 620 0° @ 4" 15° @ 12" AAD 8° 1103339 626 0° @ 4" 10° @ 8" 0°@ 12” @ 16° @ 22° @ 1100 1600 2400 4600 1103433 620 0° @ 12° @ 16” @ 22° @ 1100 1600 2400 4600 ENGINE AND EMISSION FAMILY 5.7L (350 C.I.D.) LS9 FAMILY 18L4HHNA AUTO TRANS. CALIF. SALES CK-20 5.7L (350 C.I.D.) LS9 FAMILY 18L4HHNA CALIF. SALES G10, 20 ACA ACB 8° R45TS (.045) 650 (D) 650 (D) 0 VACUUM ADVANCE (In Crank Degrees @ Inches of Vacuum) CURB IDLE (RPM) I i i i IGNITION TIMING B.T.D.C. DEGREES (© © © © EMISSION LABEL CODE 550 (D) 1800 (P or N) 17081506 17081508 w/AC Fig. 6G -2--Engine Performance Specifications LIG H T T R U C K SERVIC E M A N U A L - 0° @ 4" 15° @ 12" ENGINE PERFORMANCE SPECIFICATIONS LIGHT DUTY TRUCK ENGINE PERFORMANCE SPECIFICATION CHART VACUUM 8. MECHANICAL ADVANCE MECHANICAL VACUUM ADVANCE ADVANCE DISTRIBUTOR EMISSION LABEL CODE IGNITION TIMING B.T.D.C. DEGREES SPARK PLUG TYPE & GAP 5.7L (350 C.I.D.) LT9 FAMILY GM113 MANUAL TRANS. FEDERAL SALES CK-20 ACJ 4° 5.7L (350 C.I.D.) LT9 FAMILY GM113 MANUAL TRANS. FEDERAL SALES G-30 ACJ ACM 5.7L (350 C.I.D.) LT9 FAMILY GM113 MANUAL TRANS. CALIF. SALES CK-20, 30 SOLENOID SCREW (RPM) CURB IDLE (RPM) FAST IDLE (RPM) CARBURETOR PART NUMBER R44T (.045) *1600 700 (N) 1900 (N) 17080213 1103375 620 0° @ 4" 10° @ 8" 0 ° @ 1150 17° @ 2900 22° @ 4200 4° R44T (.045) *1600 700 (N) 1900 (N) 17080298 1103375 620 0° @ 4” 14° @ 8" 0°@ 3" 16° @ 6.5" 0 ° @ 1150 17° @ 2900 22° @ 4200 ACK 6° R44T (.045) *1500 700 (N) 1900 (N) 17080507 1103420 681 0° @ 10 10° @ 13" 0° @ 1800 24° @ 4000 5.7L (350 C.I.D.) LT9 FAMILY GM113 MANUAL TRANS. CALIF. SALES G-30 ACK 6° R44T (.045) *1500 700 (N) 1900 (N) 17080507 1103420 681 0° @ 10" 10° @ 13" 0° @ 1800 24° @ 4000 5.7L (350 C.I.D.) LT9 FAMILY GM113 MANUAL TRANS. FEDERAL SALES P-20, 30 ACJ ACM 4° R44T (.045) *1600 700 (N) 1900 (N) 17080213 1103375 626 0° @ 4" 10° @ 8" 0 ° @ 1150 17° @ 2900 22° @ 4200 5.7L (350 C.I.D.) LT9 FAMILY GM113 MANUAL TRANS. CALIF. SALES P-30 ACK 6° R44T (.045) *1500 700 (N) 1900 (N) 17080513 1103420 681 0 ° @ 10" 10° @ 13" 0° @ 1800 24° @ 4000 5.7L (350 C.I.D.) LT9 FAMILY GM113 AUTO TRANS. FEDERAL SALES CK-20, 30 ACJ 4° R44T (.045) *1600 700 (N) 1900 (N) 17080213 1103375 626 0° @ 4" 10° @ 8" 0 ° @ 1150 17° @ 2900 22° @ 4200 ACJ ACM 4° R44T (.045) *1600 700 (N) 1900 (N) 17080298 1103375 681 0° @ 4" 10° @ 8" 0° @ 1150 17° @ 2900 22° @ 4200 ACK 6° R44T (.045) *1500 700 (N) 1900 (N) 17080513 1103420 681 0° @ 4" 15° @ 10" 0 ° @ 1000 17° @ 1600 22° @ 4200 ENGINE AND EMISSION FAMILY 5.7L (350 C.I.D.) LT9 FAMILY GM113 AUTO TRANS. FEDERAL SALES G-30 5.7L (350 C.I.D.) LT9 FAMILY GM113 AUTO TRANS. CALIF. SALES CK-20, 30 DIST. MODEL VACUUM MODEL (Crank Degrees @ Engine RPM) (In Crank Degrees @ Inches of Vacuum) •THROTTLE RETURN CONTROL SPEED LIGHT DUTY TRUCK ENGINE PERFORMANCE SPECIFICATION CHART DISTRIBUTOR MECHANICAL ADVANCE (Crank Degrees @ Engine RPM) 681 0° @ 4 " 15° @ 10" 0° @ 1000 17° @ 1600 22° @ 4200 1103375 626 0° @ 4 " 14° @ 8 0° @ 1000 8° @ 1600 19° @ 3450 17080513 1103420 681 0° @ 4 " 15° @ 10" 0° @ 1000 17° @ 1600 22° @ 4200 1900 (N) 17080212 17080512 1103376 682 0° @ 8 " 10° @ 13 0° @ 1100 14° @ 2800 20° @ 4200 700 (N) 1900 (N) 17080212 17080512 1103376 682 0° @ 8 " 10° @ 13" 0° @ 1100 14° @ 2800 20° @ 4200 G LO W PLUG 575 ID) 650 (D) Mechanical Fuel Injection Injector Pump GLO W PLUG 600 (D) 750 (D) Mechanical Fuel Injection Injector Pum p EM ISSIO N LABEL CODE SPARK PLUG TYPE & GAP 5.7L (350 C.I.O.) LT9 FA M IL Y G M113 AU TO T R AN S. CALIF. S A L E S G-30 AC K 6° 5.7L (350 C.I.D.) LT9 F A M IL Y G M113 AU TO T R AN S. FED ERAL S A L E S P-30 AC J ACM 5.7L (350 C.I.D.) LT9 F A M IL Y G M113 AU TO T R A N S CA LIF S A L E S P-30 SOLENOID SCREW (RPM) CURB IDLE (RPM) FAST IDLE (RPM) CARBURETOR PART NUMBER DIST. MODEL VACUUM MODEL R44T (.045) *1500 700 (N) 1900 (N) 17080507 1103420 4° R44T (.045) *1600 700 (N) 1900 (N) 17080213 17080215 AC K 6° R44T (.045) *1500 700 (N) 1900 (N) 7.4L (454 C.I.D.) LE8 F A M IL Y G M115 M A N U A L T R AN S. N A T IO N W ID E C-20, 30; K-30 ADJ AD K 4° R44T (.045) *1500 700 (N) 7.4L (454 C.I.D.) LE8 F A M IL Y G M115 AUTO T R A N S. N A T IO N W ID E P-30 ADJ AD K 4° R44T (.045) *1500 5.7L (350 C.I.D.) LF9 FA M IL Y 19J9ZZ AU TO T R AN S. FED ER AL S A L E S C-10 O JD 8° 5.7L (350 C.I.D.) LF9 FA M IL Y 19J9ZZP AU TO T R AN S. CALIF. S A L E S C-10 HKD OHD 5° ENGINE AND EMISSIO N FAMILY VACUUM & MECHANICAL ADVANCE VACUUM ADVANCE (In Crank Degrees @ Inches of Vacuum) IGNITION TIMING B.T.D.C. DEGREES ♦THROTTLE RETURN CO N TR O L SPEE D Fig. 6G-3~Engine Performance Specifications 6G -3 it u. ,;>■ '■ ■ .• tv ■! < . f. • A U T O M A T IC TRAN SM IS S IO N 7A-1 SECTION 7 A AUTOMATIC TRANSMISSION CONTENTS T o rq u e C o n v e rter C lutch (T C C )...................................7A-1 350 A utom atic T ra n sm issio n .......................................... 7A-8 400 A utom atic T ra n s m is s io n ......................................... 7A-29 S p e c ific a tio n s.......................................................................7A-47 T O R Q U E CO N V ER T ER CLUTCH (TCC) INDEX G eneral D escription.......................................................... C onverter Clutch D iagnosis............................................ Com plaints and Possible C auses............................... Converter Clutch Applied In All Ranges............... Converter Clutch Applies E rratically ...................... Converter Clutch Applies At All T im e s................ Internal C ontrols C h eck ................................................ Internal H ydraulic/M echanical Controls Check... 7A-1 7A-4 7A-4 7A-4 7A-5 7A-5 7A-5 7A -5 External Controls C h e c k ............................................... Vacuum Switch C heck................................................. Low A nd High Vacuum Switch Check (Diesel)... High Vacuum Switch A d ju stm en t........................... Therm al Vacuum Valve C h e ck ................................. Brake Release Switch C h e ck ...................................... Solenoid Diode C h e c k ................................................. 7A-6 7A-6 7A-6 7A-6 7A-7 7A-7 7A-7 G EN ER A L D E SC R IP T IO N The torque converter clutch (as shown in Fig. 7A -la) is an internal mechanism (with a friction material attached to the front plate) splined to the turbine assembly, and when operated applies against the converter cover. This provides a mechanical direct drive coupling of the engine to the planetary gears. By applying the converter clutch, slippage is eliminated, resulting in improved fuel economy and reduced fluid operating tem peratures. The operation of the converter clutch is determined by a series of controls, and by drive range selection (as shown in Fig. 7A-2a and 2b). The converter clutch is applied in direct drive and above a m inimum preset vehicle speed. At wider throttle openings, where the 2-3 upshift occurs above converter clutch apply, the apply o f the converter clutch will occur immediately after the 2-3 shift. W hen vehicle speed decreases or the transmission shifts out of direct drive, the fluid pressure is released, the converter clutch is released, and the converter operates in a conventional manner. The apply or release of the converter clutch is determ ined by the direction that converter feed oil is fed to the converter. Converter feed oil from the pressure regulator valve flows to the converter clutch apply valve. The position of the converter clutch apply valve controls which direction converter feed oil flows to the converter. A spring loaded dam per assembly is splined to the converter turbine assembly. The converter clutch pressure plate is attached to the pivoting mechanism of the dam per assembly. This pivoting action allows the pressure plate to rotate independent of the dam per assembly, up to approximately 45 degrees. The rate of independent rotation is controlled by the pivoting mechanism acting on the springs in the dam per assembly. The spring cushioning effect of the dam per assembly aids in reducing converter clutch apply "feel." To further aid the apply and release of the converter clutch during various driving situations, controls have been incorporated in the electrical system. The converter clutch is applied when all of the following conditions exist: • • • • • Transmission in 3rd gear Vehicle exceeds 24 to 30 m ph (38 to 48 k m /h ) Engine coolant is above 130° F (54°C) Engine vacuum is above 2.5 in. hg.(8 kPa) B rake pedal is released LIGHT T R U C K SE R V IC E M A N U A L 7A-2 A U TO M A TIC TRAN SM ISSIO N TURBINE THRUST SPACER C O N V E R T E R H O US IN G COVER ASS EM B LY PRESSURE PLATE ASSEMBLY CONVERTER PUMP ASSEMBLY Fig. 7A-1 a--Torque Converter C lutch Exploded V ie w LIGHT TR U C K SE R V IC E M A N U A L A U T O M A T IC T R A N SM IS S IO N 7A-3 CRUISE CONT. HARN. ENGINE (OPENS IF COOLANT TEMP. GREATER THAN 130°F) VACUUM SWITCH (CLOSES VAC. AT 7 IN. HG. OPENS VAC. AT 2.5 IN. HG.) PASSENGER COMPARTMENT ENGINE HARNESS TRANSMISSION GOVERNOR OIL PRESSURE SWITCH (CLOSES WHEN VEHICLE SPEED EXCEEDS 24 TO 30 MPH) CONVERTER CLUTCH SOLENOID (CLUTCH IS ENGAGED IN 3RD GEAR AND SOLENOID IS ENERGIZED) Fig. 7A -2a--C onverter Clutch Controls (Gas) LIGHT T R U C K SE R V IC E M A N U A L 7A-4 A U TO M A TIC TRAN SM ISSIO N Fig. 7A-2b~C onverter C lutch C ontrols (Diesel) C O N V ER T ER CLUTCH D IA G N O S IS If engine perform ance indicates an engine tune-up is required, this should be performed, before road testing or attem pting to diagnose the transmission. Poor engine perform ance can result in rough shifting or other malfunctions. On 4 wheel drive vehicles equipped with a Torque Converter C lutch (TCC). W hen the driver shifts from 2H to 4L or 4H, the circuit to the TCC system is opened. A light is provided on the instrum ent panel to indicate when the vehicle is in 4 wheel drive. In this position (4L or 4H) converter clutch will not apply. W hen the driver shifts back to 2H, the TCC system should operate in a norm al manner. IF the vehicle does not shift out of 4 wheel drive, the light on the instrum ent panel (IP) will stay lit. The converter clutch will not apply. Use the diagnosis listed below to determ ine the problem. 3. R oad test vehicle to verify com plaint at norm al operating tem perature. Converter Clutch Applied In All Ranges, Engine Stalls When Transmission Is Put In Gear 1. position. Converter clutch valve is stuck in the A PPL Y If Converter Clutch Does Not Apply, Applies Erratically Or At Wrong Speed During Road Test COMPLAINTS AND POSSIBLE CAUSES 1. Disconnect electrical connector at transm ission case and test female connector for 12 volts using v olt/ohm meter (2000 rpm in N eutral). Before faulting any com ponent parts of the TCC system first: a. If 12 volts are present at connector, problem is internal (Refer to Internal C ontrols Check). 1. Check transm ission oil level, correct as needed. 2. Check m anual required. linkage adjustm ent, correct as b. N o voltage or low voltage present at connector, problem is external (Refer to External C ontrols Check). LIGHT TR U C K SE R V IC E M A N U A L A U T O M A T IC TRAN SM IS S IO N 7A-5 Converter Clutch Applies Erratically, A Shudder, Jerking, Jumping, or Rocking Sensation 1. Vacuum hose leak. 2. Vacuum switch malfunction. 3. Release oil exhaust orifice at pum p blocked or restricted. 4. Turbine shaft "0 "-rin g damaged. 5. Converter m alfunction, clutch pressure plate warped. 6. Solenoid bolts loose. 7. G overnor pressure switch malfunction. Converter Clutch Applies At A Very Low Or High 3rd Speed Gear 1. 2. 3. 4. 5. 6. G overnor switch m alfunction or shorted to ground. G overnor malfunction. High line pressure. Converter clutch valve sticking or binding. Solenoid inoperative or shorted to case. S o len o id screen plugged. INTERNAL CONTROLS CHECK 1. Disconnect transm ission case connector. 2. Using a 12 volt test light, connect positive lead to female connector and ground negative lead to male transm ission connector. 3. Start engine and m aintain 2000 rpm in "P A R K (P )." a. If test light comes "O N ," the governor switch or internal wiring is shorted to ground. 1. Remove oil pan and gasket. 2. Check wiring a n d /o r replace governor switch. b. If test light remains "O FF," raise the rear wheels and run vehicle in drive range until 3rd gear upshift is obtained, m aintain 2000 rpm. 1. If test light now comes "O N ," verify the operation of the Internal H ydraulic/M echanical Controls are working properly (Refer to Internal H ydraulic/M echanical Controls Check). 2. If test light remains "O F F," there is a solenoid electrical m alfunction or governor switch m alfunction. • Remove oil pan and gasket. • Using an external 12 volt source, connect positive lead to case connector term inal. Remove lead wire from governor pressure switch and connect it to the ground lead of the external 12 volt source. NOTICE: The diode in the solenoid will be damaged if the wires are connected in reverse. • If solenoid clicks, the solenoid is O K electrically, replace governor pressure switch. • If solenoid does not click, check wiring to solenoid, replace solenoid and recheck. INTERNAL HYDRAULIC/MECHANICAL CONTROLS CHECK Instructions to test governor for internal H yd rau lic/ M echanical Check. 1. O btain test a governor. 2. Cut two (2) pieces of 5/32 in. (4 mm) outside diam eter vacuum hose into 3 /8 in. (9 mm) lengths. 3. Insert one (1) piece of hose under each weight of governor (as shown in Fig. 7A-3a). 4. Remove engine vacuum switch electrical connector. 5. Using a jum per wire; connect both female term inals of electrical connector together, (to check for proper hookups, turn ignition switch to the "ON" position, raise vehicle, and check for 12 volts at transmission case female connector. If connections are correct you will have 12 volts present. 6. Replace governor with test governor. 7. Lower vehicle leaving rear wheels several inches off the ground. 8. Apply the parking brake (rear wheels m ust not be able to turn). 9. Start engine in PA R K (P ) and run at idle. 10. Step on brake pedal (this will brake current flow to transmission). 11. Put car in drive range, 3rd gear (transm ission will autom atically shift into 3rd gear because the test governor is causing high governor pressure). 12. Remove your foot from the brake pedal and the engine should stall immediately. a. If the engine stalls, the converter clutch internal hydraulic and m echanical controls are working properly. b. If the engine does not stall: • Check for missing or damaged "0 "-rin g at end of turbine shaft. • C h eck solenoid for m issing plunger. • Loose solenoid bolts. • Defective solenoid ball seat or ball. • Converter clutch apply valve sticking, binding, or damaged. LIGHT T R U C K SER V IC E M A N U A L 7A-6 A U T O M A T IC TRANSM ISSIO N • D irect clutch oil passages in pum p blocked, restricted 2. A ttach one lead of a test light to either term inal of or interconnected. the vacuum switch (low or high). 3. G round the remaining terminal of the vacuum • Converter M alfunction. switch (low or high). 13. A fter test, remove test governor and replace with 4. A ttach the remaining lead of the test light to the hot original governor. If the original governor was used for the 5. A ttach a hand vacuum pum p with a gage (J-23738 test, ensure that the weight springs are in the correct or equivalent) to the vacuum port of the vacuum switch (low position, before reinstalling in the vehicle. or high). EXTERNAL CONTROLS CHECK 6. T urn car ignition ON. 1. T urn car ignition "O N ". 7. If using a self-powered test light, connect one lead 2. Check vacuum switch connector for 12 volts and of the test light to either term inal of the vacuum switch (low check vacuum switch for proper operation. (Refer to or high) and connect the rem aining lead of the test light to Vacuum Switch Check). the other term inal of the low or high vacuum switch. Car a. If no voltage is present at switch: ignition does not have to be turned O N when using this type of test light. 1. Check fuse. 8. A ctuate hand vacuum pump. 2. Check brake switch (Refer to Brake Switch Check). a. F or LOW vacuum test light should be O FF, and 3. Check wiring to vacuum switch. remain O FF, until vacuum gage reads approximately 5.5 in. b. If 12 volts are present at switch, and switch check (18 kPa) of vacuum. OK, continue to Step 3. b. F or H IG H vacuum test light should be ON, and 3. Reconnect electrical connector to vacuum switch remain ON, until vacuum gage reads approximately 12.5 in. and using a hand held vacuum pum p with a gage (J-23738 (41 kPa) of vacuum. Test light should be O F F with vacuum or equivalent) apply 2.5 to 7 in. (18 to 23 kPa) of vacuum above 12.5 in. (41 kPa). to vacuum switch. 9. Decrease vacuum slowly. 4. W ith the ignition switch in the "O N " position, a. F or LOW vacuum test, light should remain O N check for 12 volts at female end of transm ission connector. until vacuum drops to approxim ately 4 in. (13 kPa). a. If "N O " or low voltage is present, check and repair b. F or H IG H vacuum test, light should come back ON the wire between vacuum switch and transmission. at 12.5 in. (41 kPa) high vacuum. b. if 12 volts are present at transm ission, check 10. If the LOW vacuum switch does not turn the test Therm al Vacuum Valve for proper operation (Refer to light "O N " at approxim ately 5.5 in. (18 kPa) of vacuum and Therm al Vacuum Valve Check) if operation checks OK "O FF" at approxim ately 4 in. (13 kPa) of vacuum, the low return vehicle to owner. vacuum switch is malfunctioning. VACUUM SWITCH CHECK 11. If the H IG H vacuum does not turn O F F and O N at approxim ately 12.5 in. (41 kPa) of vacuum, the high 1. D isconnect vacuum hose and electrical connector vacuum switch is malfunctioning. from vacuum switch. 2. A ttach one lead of a test light to either term inal of the vacuum switch. 3. G round rem aining term inal of vacuum switch. 4. Apply 12 volts to rem aining test light lead. 5. A ttach a hand vacuum pum p with a gage (J-23738 or equivalent) to vacuum port of switch. 6. T urn ignition "O N ". 7. A ctuate hand vacuum pump. Test light should be "O FF" and rem ain O F F until hand vacuum pum p gage reads between 2.5 and 7 in. (8 to 23 kPa) of vacuum. Test light should come "O N ". 8. Decrease vacuum slow ly-light should remain "O N " until vacuum drops to between 1.5 and 2.5 in. (5 to 8 kPa) of vacuum. 9. If the vacuum switch does not turn the test light "O N " and "O F F " between the values specified, the switch is defective. 10. The high vacuum limit, (the point at which the test light goes "O U T ") and the low vacuum limit, (the point at which the test light comes back "O N ") must have at least 4 in. (13 kPa) of vacuum difference. HIGH VACUUM SWITCH ADJUSTMENT (DIESEL) The high vacuum switch m ust be adjusted anytime the throttle rod, transmission vacuum valve and high idle speed adjustm ents are changed. 1. Disconnect high vacuum switch electrical connector. 2. Using self-powered test light, connect one lead to either term inal of the high vacuum switch and connect the probe of the test light to the other vacuum switch terminal. 3. Start engine and run at high idle speed. Energize fast idle solenoid by disconnecting pink and green wire connector from coolant switch located on the left rear of the engine on the intake manifold. 4. Remove seal cap on back of high vacuum switch. 5. High vacuum switch contacts m ust be closed (test light O N ) before m aking adjustm ent. If contacts are open (test light O FF), turn switch adjustm ent screw clockwise until contacts close (test light ON). 6. A djust vacuum switch by slowly turning the adjustm ent screw counterclockwise until switch contacts just open (test light O FF). T urn adjustm ent screw slowly LOW AND HIGH VACUUM SWITCH CHECK to prevent adjusting past this position. (DIESEL) 7. Reinstall seal cap on back of switch, reconnect high 1. Disconnect vacuum hose and electrical connector vacuum switch electrical connector, and reconnect coolant switch connector. from vacuum switch (low or high). LIGHT TR U C K SE R V IC E M A N U A L A U TO M A TIC TR A N SM IS S IO N IF A IR CLEANER IS REM OVED WHEN M A K IN G SW IT C H ADJUSTM ENT. THE EGR SO LENO ID PORT TO THE EGR VA LVE M UST BE PLUGGED TO PREVENT A VA CU UM LEAK AT THE EGR SO LEN O ID . 7A-7 4. Connect one lead of the test light to the remaining brake release switch terminal. 5. A ttach rem aining lead of test light to brake connector wire. The test light should now be "O N ". 6. A pply brakes. Test light should now go "O U T". If test light is "O F F" before applying brakes or "O N " during brake apply, switch is malfunctioning, replace switch. SOLENOID DIODE CHECK Solenoids should not be bench tested by touching the leads to an autom otive battery. The internal diode will be destroyed by touching the negative term inal (BLA CK , m arked with -) to the positive battery term inal and the positive term inal (R ED , +) to negative battery terminal. Fig. 7A-4a— High Vacuum Switch Adjustment THERM AL V A C U U M VALVE CHECK 1. D isconnect vacuum hose at vacuum switch. 2. A ttach vacuum gage to hose. 3. Start car and check vacuum in Park(P). a. W ith engine cold, engine coolant tem perature below 130° F (54°C), vacuum at idle and at 2000 rpm should read zero(O). b. W ith engine warm (approxim ately five minutes running time at fast idle), engine coolant tem perature above 130° F (54°C), vacuum at idle should be zero(O), while vacuum at 2000 rpm should be 10 in. (33 kPa) minimum. Diode used in solenoids may be checked using O N LY a M E T E R R E A D IN G or SCA LE-TY PE ohm meter, set on the X I SCALE. Electronic or digital-type meters, C A N N O T be used because a false defective indication can be obtained. Proper procedure is as follows: 1. Set the SC A LE-TY PE or M E T E R -R E A D IN G ohm m eter on the X I SCA LE and zero the needle. 2. A ttach the PO SITIV E SO LEN O ID LEA D (R ED , marked with +) to the POSITIVE METER LEAD and the NEGATIVE SOLENOID LEAD (black, marked - ) to the NEGATIVE METER LEAD. a. A m eter reading of 20 to 40 ohms (depending on solenoid tem perature), diode or coil is nor shorted. BRAKE SW ITC H CHECK b. A m eter reading of 0 ohms, diode or coil is shorted. 1. D isconnect electrical connector from rear of brake switch. These are the cruise co ntrol/converter clutch release terminals. c. Open circuit reading, coil is open. 2. T urn ignition switch on the "O N " position. 3. Now ground one of the term inals of the brake release switch. 3. Reverse the solenoid lead attachm ent. a. Lower reading than in Step 2 (usually 2 to 15 ohms), solenoid is OK. b. Same reading as in Step 2, diode is open. LIGHT TRU CK SE R V IC E M A N U A L 7A-8 A U TO M A TIC TRAN SM ISSIO N 350 A U T O M A T IC T R A N S M IS S IO N INDEX General D escription.......................................................... .7A-8 M aintenance and A d ju stm e n t.........................................7A-9 Transm ission F lu id ..........................................................7A-9 Checking Transm ission M o u n t................................... .7A -11 Shift C o n tro ls................................................................... .7A-11 D etent Downshift C able............................................... .7A-12 N eutral Start S w itch........................................................7A-12 D iagnosis...............................................................................7A -14 Diagnosis Sequence......................................................... .7A-14 Fluid Checking P ro ced u res.......................................... .7A-14 Fluid Leak D iagnosis.......................................................7A-14 Fluid Pressure C heck..................................................... .7A-15 Case Porosity R e p a ir..................................................... .7A-15 Vacuum M odulator D iag n o sis.................................... .7A -15 Clutch Plate D iagnosis........................................ ...........7A-16 Causes of Burned C lutch Plates.................................. .7A-16 G overnor Pressure C heck...............................................7A-17 M anual L in k ag e................................................................7A-17 Road T e st.......................................................................... Trouble D iagnosis........................................................... Clutch Apply C h a rt........................................................ Diagnosis C h a r t............................................................... H ydraulic C ircuit............................................................. On Vehicle Service............................................................. Transmission Replacement (Except K M odels)...... Transm ission Replacem ent (K M odels)..................... Extension Housing Oil Seal........ .................................. Speedometer Driven G e a r............................................. Speedometer Drive G e a r ............................................... M anual Shaft, Range Selector Inner Lever and Parking L inkage.......................................................... G o v e rn o r........................................................................... Vacuum M odulator and M odulator V alve............... Valve Body A ssem bly..................................................... 1-2 A c c u m u la to r............................................................ Oil C o oler P i p e s ............................................................ 7A -17 7A -17 7A-21 7A-22 7A-23, 24 7 A -25 7A-25 7A-25 7A-26 7A-26 7A-26 7A-27 7A-27 7A-28 7A-28 7A-28 7A-29 G EN ER A L D E SC R IP T IO N The 350 transmission is a fully autom atic unit consisting prim arily of a 3-element hydraulic torque converter and two planetary gear sets. Four multiple-disc clutches, two roller clutches, and an interm ediate overrun band provide the friction elements required to obtain the desired function of the two planetary gear sets. The 3-element torque converter consists of a pump, turbine and a stator assembly, with the addition of a converter clutch. The stator is m ounted on a one way roller clutch which will allow the stator to turn clockwise, but not counterclockwise. References to clockwise and counterclockwise are determ ined by looking toward rear of vehicle. The torque converter is of welded construction and is serviced as a complete assembly. The unit is filled with oil and is attached to the engine crankshaft by a flywheel, thus always rotates at engine speed. The converter pum p is an integral part of the converter housing, therefore, the pump blades, rotating at engine speed, set the oil within the converter into m otion and direct it to the turbine, causing the turbine to rotate. As the oil passes throughout the turbine it is traveling in such a direction th at if it were not redirected by the stator it would hit the rear of the converter pum p blades and impede its pumping action. So at low turbine speeds, oil is redirected by the stator to the converter pum p in such a m anner that it actually assists the converter pum p to deliver power, or multiply engine torque. As turbine speed increases, the direction of oil leaving the turbine changes and flows against the rear side of the stator vanes in a clockwise direction. Since the stator is now impeding the sm ooth flow of oil, its roller clutch releases and it revolves freely on its shaft. Once the stator becomes inactive, there is no further m ultiplication of engine torque within the converter. A t this point, the converter is merely acting as a fluid coupling as both the converter pum p and turbine are being driven at approximately the same speed. A hydraulic system pressurized by a gear type pum p provides the working pressure required to operate the friction elements and autom atic controls. External control connections to the transmission are: • M anual Linkage - To select the desired operating range. • Engine Vacuum - To operate the vacuum m odulator. • Cable Control - To operate the detent valve. A vacuum m odulator is used to autom atically sense any change in the torque input to the transmission. The vacuum m odulator transm its this signal to the pressure regulator, which controls line pressure, so that all torque requirements of the transm ission are met and sm ooth shifts are obtained at all throttle openings. The detent valve is activated by a cable that is connected to the accelerator lever assembly. W hen the throttle is half open, the valve is actuated causing throttle downshift at speeds below 50 m ph, (80 km /h). W hen the throttle is fully open the detent valve is actuated causing the transm ission to downshift from 3-1 at speeds below 40 mph (65 k m /h ) and 3-2 below 75 m ph (120 km /h). LIGHT T R U C K SE R V IC E M A N U A L AU TO M A TIC TRAN SM ISSIO N CONVERTER ASSEMBLY INTERMEDIATE CLUTCH INTERMEDIATE BAND 7A-9 FORWARD CLUTCH LOW AND REVERSE CLUTCH SUN GEAR OUTPUT SHAFT REACTION CARRIER GOVERNOR AND REVERSE OVERRUN ROLLER INPUT SHAFT PARKING PAWL OUTPUT CARRIER STATOR SHAFT INTERMEDIATE OVERRUN ROLLER CLUTCH MANUAL SHAFT Fig. 7 A - 1 - 3 5 0 Autom atic Transm ission, Cross-Section V iew M A IN T E N A N C E A N D A D J U S T M E N T S TRANSMISSION FLUID F luid Level an d C a p a c ity The fluid level indicator is located in filler tube at right rear of engine. To bring the fluid level from the "A D D " mark to the "FU L L" mark requires one pint of fluid. Fluid level should be checked at every engine oil change. Fluid level should be to the FU LL m ark with the transmission fluid at normal operating tem perature of 200°F (93°C). W ith warm fluid at room tem perature of 70°F (21°C), the level will be 1/4 in. (6 mm) below the A D D m ark 011 the dipstick. The normal operating tem perature is obtained only after at least 15 miles (24 k m /h ) of highway type driving or the equivalent of city driving. LIGHT TRU C K SE R VIC E M A N U A L 7A-10 A U TO M A TIC TRANSM ISSION NOTICE: DO NOT O V E R FIL L (or this may cause damage to the transmission) as foaming and loss of fluid through the vent pipe might occur as fluid heats up. If fluid is too low, especially when cold, complete loss of drive may result, which can cause transmission failure. D ra in in g an d R e fillin g T ra n s m is s io n O il P an NOTE: DO NOT OVERFiLL. IT TAKES ONLY ONE PINT TO RAISE L E V E L FROM ADD TO FULL WITH A HOT TRANSMISSION. Fig. 7A -2 ~ D ip stick Approxim ately 3 liters (6 pints) of fluid are required to refill the transmission after the oil pan has been drained. The fluid capacity of the 350 transmission and converter assembly is approximately 10 liters (20 pints) but correct level is determined by the mark on the dipstick rather than by amount added. Use only D E X R O N ® II autom atic transm ission fluid or its equivalent. An early change to a darker color from the usual red color a n d /o r a strong odor that is usually associated with overheated transmission fluid is normal, and is not a positive sign of required m aintenance or transmission failure. C h e c k in g P ro c e d u re an d A d d in g Fluid To determ ine proper fluid level at norm al operating tem perature, proceed as follows: 1. Position vehicle on a level surface, place selector lever in P A R K (P), apply parking brake and have engine running at norm al idle. 2. Remove fluid level indicator, wipe it clean and reinstall fully until cap seats. 3. Remove indicator and reading of fluid level should be at full "F" mark. 4. If additional fluid is required, add D E X R O N ® II autom atic transm ission fluid or its equivalent to "F" mark on indicator. If the vehicle cannot be driven sufficiently to bring the transm ission to operating tem perature and it becomes necessary to check the fluid level, the transmission may be checked at room tem perature of 70°F (21°C) as follows: 1. Position selector lever in PA R K (P), apply parking brake and start engine. DO N O T R A C E E N G IN E . Move selector lever through each range. 2. Im m ediately check fluid level with selector lever in Park, engine running and vehicle on LEVEL surface. Fluid level on indicator should be 1/4 in. (6 mm) below the "A D D " mark. 3. If additional fluid is required, add enough fluid to bring level to 1/4 in. (6 mm) below the A D D m ark on the dipstick. If transmission fluid level is correctly established at 70°F, (21°C), it will appear at the FU LL m ark on the dipstick when the transm ission reaches its norm al operating tem perature of 200°F, (93°C). The oil pan should be drained and the strainer cleaned at the intervals detailed in Section O-B of this manual, and fresh fluid added to obtain the proper level on indicator. Section O-B also details intervals for vehicles subjected to heavy city traffic during hot weather, or in commercial use, or when the engine is regularly idled for prolonged periods or when vehicle is used for towing. D rain fluid immediately after operation before it has had an opportunity to cool. Transm ission fluid tem perature can exceed 350°F, (177°C). 1. Raise vehicle. 2. Support transmission with suitable jack at the transmission. 3. W ith fluid receptacle placed under transmission oil pan, remove oil pan attaching bolts from front and side of pan. 4. Loosen rear pan attaching bolts approximately four (4) turns. 5. Carefully pry transm ission oil pan loose with screwdriver, allowing fluid to drain. 6 Remove remaining screws and remove oil pan and gasket. Discard gasket. 7. D rain fluid from oil pan. Clean pan with solvent and dry thoroughly with clean compressed air. 8. Remove two (2) strainer-to-valve body screws, strainer and gasket. Discard gasket. 9. Thoroughly clean strainer assembly in solvent and dry throughly with clean compressed air. 10. Install new strainer-to-valve body gasket, strainer and two (2) screws. 11. Install new gasket on oil pan and install oil pan. Tighten its 13 attaching bolt and washer assemblies to 12 ft. lb. (16 N -m ) torque. 12. Lower vehicle. A dd approxim ately 3 liters (6 pints) of D E X R O N ® II autom atic transmission fluid or its equivalent through filler tube. 13. W ith selector lever in P A R K (P) position, apply hand brake, start engine and let idle (carburetor off fast idle step). DO N O T RA CE E N G IN E . 14. Move selector lever through each range and, with selector lever in PA R K (P) range, check the fluid level. 15. A dd additional fluid to bring level to 1/4 in. (6.35 mm) below the A D D m ark on the dipstick. NOTICE: Do not overfill. Foam ing can result if overfilled. A d d in g F luid to Fill D ry T ra n s m is s io n an d C o n v e rte r A s s e m b ly In cases of transmission overhaul, when a complete fill of approximately 10 liters (20 pints) is required, proceed as follows: LIGHT TR U C K SE R V IC E M A N U A L AU TO M A TIC TRANSM ISSIO N 1. Add a sufficient quantity of transmission fluid through filler tube to raise the level to the lower portion of the dipstick. 2. With manual control lever in PA R K (P) position, start engine and place on cold idle cam. DO N O T RA C E E N G IN E . Move manual control lever through each range. 3. Immediately check fluid level with selector lever in PA R K (P), engine running and vehicle on LEVEL surface and add additional fluid to bring level to 1/4 in. (6.35 mm) below the "A D D " mark on the dipstick. Do not overfill. CHECKING TRANSMISSION MOUNT Raise vehicle on a hoist. Push up and pull down on transmission tailshaft while observing transmission mount. If rubber separates from metal plate of mount or if tailshaft moves up but not down (m ount bottom ed out) replace mount. If there is relative movement between a metal plate of m ount and its attaching point, tighten screws or nuts attaching mount to transmission or crossmember. SHIFT CONTROLS Column S h ift Linkage - CK and P Series (Fig. 7A-3 and 4) 1. The shift tube and lever assembly must be free in the mast jacket. See Section 3B for alignment of steering column assembly if necessary. 2. To check for proper shift linkage adjustm ent, lift the transmission selector lever towards the steering wheel. Allow the selector lever to be positioned in D R IV E (D) by the transm ission detent. Do not use the indicator pointer as a reference to position the selector lever. W hen performing linkage adjustm ent, pointer is adjusted last. 7 A -1 1 3. Release the selector lever. The lever should be inhibited from engaging low range unless the lever is lifted. 4. Lift the selector lever tow ards the steering wheel, and allow the lever to be positioned in N E U T R A L (N) by the transmission detent. 5. Release the selector lever. The lever should now be inhibited from engaging reverse range unless the lever is lifted. 6. A properly adjusted linkage will prevent the selector lever from moving beyond both the neutral detent, and the drive detent unless the lever is lifted to pass over the mechanical stop in the steering column. 7. If adjustm ent is required, remove screw (A) and spring washer from swivel (B). 8. Set transmission lever (C) in N eutral (N) position by moving lever counterclockwise to LI detent and then clockwise three (3) detent positions to N EU TR A L(N ). 9. Position transmission selector lever in N E U T R A L (N ) position as determ ined by the mechanical stop in steering column assembly. Do not use the indicator pointer as a reference to position the selector lever. W hen performing linkage adjustm ent, pointer is adjusted last. 10. Assemble swivel, spring washer and screw to lever assembly (D) and tighten screw to 20 ft. lb. (27 N*m) 11. Readjust indicator needle if necessary to agree with the transmission detent positions. Refer to Section 9. 12. Readjust neutral start switch if necessary to provide the correct relationship to the transmission detent positions. Refer to Section 8. 13. Check operation (CK Series): a. With key in "Run" position and transmission in REV ERSE(R) be sure that key cannot be removed and that steering wheel is not locked. b. With key in "Lock" position and shift lever in P A R K (P), be sure that key can be removed, that steering wheel is locked, and that transmission remains in PA R K (P) LIGHT TR U C K SE R V IC E M A N U A L 7A-12 A U T O M A T IC TRAN SM ISSIO N P. WASHER GROMMET, COLUMN SHIFT LEVER BUSHING CLAMP E L. WASHER NUT F COLUMN ASSEMBLY SWIVEL D ROD A TRANS LEVER C 3. Set the column shift lever in N E U T R A L (N) position. This is obtained by rotating shift lever until it locks into m echanical stop in the colum n assembly. Do not use indicator pointer as a reference to position the shift lever. 4. A ttach rod (A) to shaft assembly (B) as shown (Fig. 7A-5). 5. Slide swivel (D ) and clam p (E) onto rod (A) align the colum n shift lever and loosely attach as shown. 6. H old colum n lever against "neutral" stop "park" position side. 7. Tighten nut (F) to 18 ft. lb. (24 N*m) TRANSMISSION (7) j GROMMET SHAFT ASSEMBLY B 8. R eadjust indicator needle if necessary to agree with the transm ission detent positions. 9. R eadjust neutral start switch if necessary to provide the correct relationship to the transm ission detent positions. Fig. 7A-5--Column Shift Linkage-G Series when steering colum n is locked. NOTICE: A ny inaccuracies in the above adjustm ents m ay result in prem ature failure of the transm ission due to operation w ithout controls in full detent. Such operation results in reduced oil pressure and in turn partial engagem ent of the affected clutches. Partial engagement of the clutches with sufficient pressure to cause apparent norm al operation of the vehicle will result in failure of the clutches or other internal parts after only a few miles of operation. NOTICE: A ny inaccuracies in the above adjustm ents may result in prem ature failure of the transm ission due to operation w ithout controls in full detent. Such operation results in reduced oil pressure and in turn partial engagement of the affected clutches. Partial engagement of the clutches w ith sufficient pressure to cause apparent norm al operation of the vehicle will result in failure of the clutches or other internal parts after only a few miles of operation. NEUTRAL START SWITCH Column Shift Linkage - G Series (Fig. 7A-5) The adjustm ent of the neutral start switch is described in Section 8> Electrical. 1. The shift tube and lever assembly m ust be free in the mast jacket. 2. Set transm ission lever (C) in "neutral" position by one of the following optional methods. Obtain N E U T R A L (N ) position by moving transmission lever (C) counter-clockwise to "L I" detent, then clockwise three detent positions to "neutral" or obtain "neutral" position by moving transm ission lever (C) clockwise to the P A R K (P ) detent then counter-clockwise two detents to N E U T R A L (N ). LIGHT TR U C K SE R V IC E M A N U A L A U T O M A T IC TRAN SM IS S IO N 7 A -1 3 DETENT CABLE ADJUSTMENT PROCEDURE 1. AFTER INSTALLATION INTO TRANSMISSION, IN­ S TA L L C A BLE F I T T ING I N T O E N G I N E B R A C K E T . IC A U TIO N l S L I D E R M U S T N O T RATCHET THROUGH THE FITTING BEFORE OR DURING ASSEMBLY INTO BRACKET. USE THE RE­ ADJUSTMENT PROCEDURE TO CORRECT THIS CONDITION. 2. INSTALL CABLE TER M IN A L TO CARBURETOR LEVER. 3. OPEN CARBURETOR LEVER TO "FULL THROTTLE STOP” POSITION TO AUTOMATICALLY ADJUST SLIDER ON C A BLE TO CORRECT SETTING. ICAUTIONl LOCK TAB MUST NOT BE DEPRESSED DURING THIS OPERATION. 4. RELEASE CARBURETOR LEVER. DETENT CABLE RE-ADJUSTMENT PROCEDURE IN CASE RE-ADJUSTMENT IS NECESSARY BECAUSE OF INADVERTENT ADJUSTMENT BEFORE OR DUR­ ING ASSEMBLY, OR FOR REPAIR, PERFORM THE FOLLOWING: 1. DEPRESS AND HOLD METAL LOCK TAB. 2. MOVE SLIDER BACK THROUGH FITTING IN DIREC­ TION AWAY FROM CARBURETOR LEVER UNTIL SLIDER STOPS AGAINST FITTING. TRANSMISSION ASSEMBLY 3. RELEASE METAL LOCK TAB. 4. R E P E A T S T E P S 2, 3 & 4 OF A D J U S T M E N T PROCEDURE. LINK — TRANSMISSION I VIEW A B RA CK ETENGINE LEVER CARBURETOR VIEW B Fig. 7A-6— Detent Cable Adjustm ent - V-8 LIGHT TRU C K SE R V IC E M A N U A L 7A-14 AUTOMATIC TRANSMISSION VIEW A BOTH LOCKING LUGS MUST BE EXPANDED AND LOCKED IN HOLE SLIDER RE-ADJUST DIRECTION LOCK TAB T.V./DETENT CABLE BRACKET TERMINAL VIEW B LEVER ASSEMBLY CABLE ADJUSTMENT PROCEDURE 1. Remove pump rod from lever assembly. 2. After installation to transmission, install cable fitting into cable bracket. CAUTION Slider must not be ad­ justed before or during assembly to bracket. 3. Install cable terminal to lever assembly. 4. Rotate the lever assembly to its full throttle stop position to automatically adjust slider on cable to correct setting. 5. Release lever assembly & reconnect the pump rod to lever assembly. CABLE RE-ADJUSTMENT PROCEDURE In case re-adjustment is necessary because of inadver­ tent adjustment before or during assembly, perform the following. 1. Remove pump rod from lever assembly, depress and hold metal lock tab. 2. Move slider through fitting in direction away from lever assembly until slider stops against fitting. 3. Release metal lock tab. 4. Repeat steps 4 & 5 of adjustment procedure. Fig. 7A-6a— Detent Cable A djustm ent - Diesel LIGHT T R U C K SE R V IC E M A N U A L A U T O M A T IC TR A N SM IS S IO N 7 A -1 5 DETENT CABLE ADJUSTMENT PROCEDURE 1. A F T E R IN S T A L L A T IO N INTO T R A N S M IS S IO N , IN­ S T A L L C A B L E FITTING INTO E N G IN E B R A C K ET . CAUTION S L ID E R M U ST NOT RATCHET T H R O U G H T H E FITTING B E F O R E O R D U R IN G A S S E M B L Y INTO B R A C K E T . U S E T H E R E A D J U S T ­ M E N T P R O C E D U R E TO C O R R E C T T H IS C O N D I­ TION. 2. IN S T A L L LEVER. CABLE T E R M IN A L TO CARBURETOR 3. O P E N C A R B U R E T O R L E V E R T O “FU LL T H R O T T LE S T O P ” P O S IT IO N TO A U T O M A T IC A L L Y A D JU S T S L ID E R O N C A B L E TO C O R R E C T SET T IN G . CAUTION L O C K T A B M U S T NO T B E D E ­ P R E S S E D D U R IN G T H IS O P E R A T IO N . 4. R E L E A S E C A R B U R E T O R LE V E R . DETENT CABLE RE-ADJUSTMENT PROCEDURE IN C A S E R E -A D J U S T M E N T IS N E C E S S A R Y B E C A U S E OF IN A D V E R T E N T ADJU STM EN T BEFORE OR D U R IN G A S S E M B L Y , O R F O R R E P A IR , P E R F O R M THE F O L L O W IN G : 1. D E P R E S S A N D H O L D M E T A L L O C K TAB. 2. M O V E S L ID E R B A C K T H R O U G H FITTING IN D IR E C T IO N A W A Y F R O M C A R B U R E T O R L E V E R U N T IL S L ID E R S T O P S A G A IN S T FITTING. 3. R E L E A S E M E T A L L O C K TAB. 4. R E P E A T S T E P S 2, 3 & 4 O F A D J U S T M E N T P R O ­ CEDURE. Fig. 7A-7— Detent Cable Adjustm ent - L-6 D IA G N O S IS DIAG NO SIS SEQUENCE FLUID CHECKING PROCEDURES 2. Check detent cable adjustm ent. Refer to M aintenance and A djustm ent Section for fluid checking procedures. 3. Check and correct vacuum line and fittings. FLUID LEAK DIAG NO SIS 1. Check and correct fluid level. 4. Check and correct m anual linkage. 5. Road test vehicle. a. Install oil pressure gage. b. Road test using all selective ranges, noting when discrepancies in operation or oil pressure occur. c. A ttem pt to isolate the unit or circuit involved in the malfunction. d. If engine perform ances indicates an engine tune-up is required, this should be performed before road testing is completed or transmission correction attem pted. Poor engine perform ance can result in rough shifting or other malfunctions. Determining Source of Leak Before attem pting to correct an oil leak, the actual source of the leak must be determ ined. In many cases, the source of the leak can be deceiving due to "wind flow" around the engine and transmission. The suspected area should be wiped clean of all oil before inspecting for the source of the leak. The use of a "Black Light" to locate the point at which the oil is leaking is helpful. Com paring the oil from the leak to that on the engine or transmission dipstick, when viewed by black light, will determ ine the source of the leak - engine or transmission. LIG HT T R U C K SE R V IC E M A N U A L 7A-16 A U T O M A T IC TRAN SM ISSIO N Oil leaks around the engine and transm ission are generally carried tow ard the rear of the vehicle by air stream. F or example, a transm ission oil filler tube to case leak will sometimes appear as a leak at the rear of the transmission. In determ ining the source of a leak, proceed as follows: 1. Degrease underside of transmission. 2. Road test to get unit at operating tem perature. 3. Inspect for leak with engine running. 4. W ith engine O F F, check for oil leaks due to the raised oil level caused by drain back. Possible Points of Oil Leak 1. Transmission Oil Pan Leak. a. A ttaching bolts not correctly torqued. b. Im properly installed or damaged pan gasket. c. Oil pan gasket m ounting face not flat. 2. Extension Housing. a. A ttaching bolts not correctly torqued. b. R ear seal assembly damaged or im properly installed. c. Square seal, extension to case, damaged or improperly installed. d. Porous casting. Refer to Subparagraph C. 3. Case Leak. a. Filler pipe seal dam aged or missing; misposition of filler pipe bracket to engine. b. M odulator assembly "O" ring seal damaged or im properly installed. c. D etent cable connector seal dam aged or improperly installed. d. G overnor cover not tight. e. Speedometer gear "O" ring damaged. f. M anual shaft seal dam aged or im properly installed. g. Line pressure tap plug loose. h. Vent pipe (refer to item 5). i. Porous casting. Refer to Subparagraph C. 4. Leak at F ro n t of Transmission. a. F ront pum p seal leaks. 1. Seal lip cut. Check converter hub, etc. 2. Bushing moved and damaged, Oil return hole plugged. 3. No oil return hole. b. F ront pum p attaching bolts loose or bolt washer type seals dam aged or missing. c. F ront pum p housing "O" ring damaged or cut. d. Converter leak in weld area. e. Porous casting (pump). 5. Oil Comes O ut Vent Pipe. a. Transm ission overfilled. b. W ater in oil. c. Foreign m aterial between pum p and case or between pump cover and body. d. Case - porous near converter bosses. F ront pum p cover or housing oil channels shy or stock near breather. See Subparagraph C. e. Pum p to case gasket mispositioned. FLUID PRESSURE CHECK W hile vehicle is stationary (service brake ON), engine speed set to 1200 rpm, transm ission oil pressure gage attached as shown in Fig. 7A-10B, and vacuum m odulator tube disconnected , the transm ission line pressure tap should read 167 psi (1152 kPa) in Drive(D), 166 psi (1145 kPa) in LI or L2, and 254 psi (1752 kPa) in reverse. While vehicle is stationary (service brake ON), engine speed set to m aintain 12 in. hg. (39 kPa) absolute manifold pressure, transm ission oil pressure gage attached, and vacuum m odulator tube connected , the transmission line pressure tap should read 85 psi (586 kPa) in D R IV E (D), 105 psi (724 kPa) in LI or L2, and 129 psi (890 kPa) in reverse. CASE POROSITY REPAIR External oil leaks caused by case porosity can be successfully repaired with the transm ission in the vehicle by using the following recom m ended procedures: 1. Road test and bring the transm ission to operating tem perature, approxim ately 180°F (82°C). 2. Raise vehicle on a hoist or jack stand, engine running, and locate source of oil leak. Check for oil leaks in Low(L), D rive(D ), and Reverse(R). 3. Shut engine off and thoroughly clean area to be repaired with a suitable cleaning solvent and a brush and air dry. A clean, dry soldering acid brush can be used to clean the area and also to apply the epoxy cement. 4. Using instructions of the m anufacturer, mix a sufficient am ount of epoxy to m ake the repair. M ake certain the area to be repaired is fully covered. 5. Allow cement to cure for 3 hours before starting engine. 6. R oad test and check for leaks. VACUUM MODULATOR DIAGNOSIS A defective vacuum m odulator can cause one or more of the following complaints. 1. H arsh upshifts and downshifts. 2. Delayed upshifts. 3. Soft upshifts and downshifts. 4. Slips in Low(L), D rive(D ) and Reverse(R). 5. Transmission overheating. 6. Engine burning transm ission oil. If any one of the above com plaints are encountered, the m odulator must be checked. Vacuum Diaphragm Leak Check Insert a pipe cleaner into the vacuum connector pipe as far as possible and check for the presence of transmission oil. If oil is found, replace the m odulator. Gasoline or w ater vapor may settle in the vacuum side of the m odulator. If this is found w ithout the presence of oil, the m odulator is serviceable and should not be changed. Atmospheric Leak Check Apply a liberal coating of soap bubble solution to the vacuum connector pipe seam, the crim ped upper to lower housing seam (Fig. 7A-8). Using a short piece of rubber tubing, apply air pressure to the vacuum pipe by blowing into the tube and observe for leak bubbles. If bubbles appear, replace the m odulator. LIGHT T R U C K SE R V IC E M A N U A L AU TO M A TIC TRAN SM ISSIO N 7A -17 Sleeve Alignment Check Roll the main body of the m odulator on a flat surface and observe the sleeve for concentricity to the cam. If the sleeve is concentric and the plunger is free, the m odulator is acceptable. Once the m odulator assembly passes all of the above tests, it is an acceptable part and may be reused. TRANSMISSION CLUTCH PLATES DIAGNOSIS 1. а. surface 1. 2. Fig. 7 A -8 ~ V a cu u m M o d u la to r A sse m b ly NOTICE: D o not use any m ethod other than hum an lung power for applying air pressure, as pressures over 6 psi (41 kPa) may dam age the m odulator. Spring Tension Comparison Check Using tool J-24466, as shown in Fig. 7A-9, compare the load of a known good m odulator with the assembly in question. a. Install the m odulator th at is known to be acceptable on either end of the tool. b. Install the m odulator in question on the opposite end of the tool. c. H olding the m odulators in a horizontal position, bring them together under pressure until either m odulator sleeve ju st touches the tool. The indicator in the gage will show white if the m odulator is acceptable. A nonconforming m odulator will cause the indicator to shift, thus showing blue. If white does not appear, the m odulator in question should be replaced. HOLD MODULATORS IN A HORIZONTAL POSITION, AS SH O W N , BRING THEM SLOWLY TOGETHER UNDER PRESSURE Fig. 7A-9--Spring Tension C om parison Lined Drive Plates. Dry plates with compressed air and inspect the lined for: pitting and flaking wear 3. glazing 4. cracking 5. charring б. chips or metal particles imbedded in lining. If a lined drive plate exhibits any of the above conditions, replacement is required. Do not diagnose drive plates by color. 2. Steel Driven Plates Wipe plates dry and check for heat discoloration. If the surface is sm ooth and an even color smear is indicated, the plate should be reused. If severe heat spot discoloration or surface scuffing is indicated, the plate must be replaced. 3. Clutch Release Springs Evidence of extreme heat or burning in the area of the clutch may have caused the springs to take a heat set and would justify replacem ent of the springs. CAUSES OF BURNED CLUTCH PLATES 1. FO R W A R D C LU TC H a. Check ball in clutch housing damaged, stuck or missing. b. Clutch piston cracked, seals damaged or missing. c. Low line pressure. d. Pum p cover oil seal rings missing, broken or undersize; ring groove oversize. e. Case valve body face not flat or porosity between channels. 2. IN T E R M E D IA T E CLU TC H a. Interm ediate clutch piston seals damaged or missing. b. Low line pressure. c. Case valve body face not flat or porosity between channels. 3. D IR E C T CL U T C H a. Restricted orifice in vacuum line to m odulator (poor vacuum response). b. Check ball in direct clutch piston damaged, stuck or missing. c. Defective m odulator bellows. d. Clutch piston seals damaged or missing. e. Case valve body face not flat or porosity between channels. f. Clutch installed backwards. NOTICE: Burned clutch plates can be caused by incorrect usage of clutch plates. Also, anti-freeze in transmission fluid can cause severe damage, such as LIGHT TR U C K SER V IC E M A N U A L 7A-18 A U TO M A TIC TRAN SM ISSIO N Low L1 Range Position the selector lever in LI range and accelerate the vehicle from 0 mph (0 k m /h). No upshift should occur in this range. 2ND Gear - Overrun Braking: (L2) COOLER O il TO RADIATOR 1-2 CLUTCH (INTERMEDIATE) PRESSURE TAP Position the selector lever in D R IV E R A N G E , and with the vehicle speed at approxim ately 35 m ph (56 k m /h ), move the selector lever to L2 R A N G E. The transmission should downshift to 2nd. An increase in engine R PM and an engine braking effect should be noticed. Line pressure should change from approxim ately 100 psi (690 kPa) to approxim ately 125 psi (875 kPa) in 2nd. COOLER OIL FROM RADIATOR DETENT CONTROL VALVE WIRE HOLE ...... * 2-3 CLUTCH (DIRECT) PRESSURE TAP W ‘4 m LINE PRESSURE TAP Fig. 7 A -1 0 -P r e ss u r e T ap Lo cation s large pieces of composition clutch plate m aterial peeling off. M ANUAL LINKAGE M anual linkage adjustm ent and the associated neutral safety switch are im portant from a safety standpoint. The neutral safety switch should be adjusted so that the engine will start in the Park (P) and N eutral (N ) positions only. W ith the selector lever in the PA R K (P ) position, the parking pawl should freely engage and prevent the vehicle from rolling. The pointer on the indicator quadrant should line up properly with the range indicators in all ranges. ROAD TEST Drive Range Position selector lever in D R IV E (D) range and accelerate the vehicle from 0 m ph (0 km /h ). A 1-2 and 2-3 shift should occur at all throttle openings. (The shift points will vary with the throttle opening). As the vehicle decreases in speed to 0 m ph (0 k m /h ), the 3-2 and 2-1 shifts should occur. Low L2 Range Position the selector lever in L2 range and accelerate the vehicle from 0 m ph (0 km /h ). A 1-2 shift should occur at all throttle openings. (No. 2-3 shift can be obtained in this range). The 1-2 shift point will vary with throttle opening. As the vehicle decreases in speed to 0 m ph (0 k m /h), a 2-1 shift should occur. The 1-2 shift in IN T E R M E D IA T E (D ) range is somewhat firm er than in D R IV E R A N G E . This is normal. 1ST Gear - Overrun Braking: (L1) Position the selector lever in L2 R A N G E at approxim ately 30 to 50 M PH (48 to 80 k m /h), with throttle closed, move the selector lever to L I. A 2-1 dow nshift should occur in the speed range of approximately 45 to 30 m ph (70 to 48 km /h ), depending on axle ratio and valve body calibration. The 2-1 downshift at closed throttle will be accompanied by increased engine rpm and an engine braking effect should be noticed. Line pressure should be approxim ately 150 psi (1035 kPa). Stop vehicle. Reverse Range: (R) Position the selector lever in R EV ER SE(R ) Position and check for reverse operation. TROUBLE DIAGNOSIS, BY CONDITION Refer to Fig. 7A-12, (Diagnosis Chart), to determ ine a possible cause of a transm ission problem. A dditional diagnosis of a malfunction is as follows: No Drive in Drive (D) Range (Install pressure gage) • Low Oil Level - correct level and check for external leaks or defective vacuum m odulator (leaking diaphragm will evacuate oil from unit). • M anual Linkage - m isadjusted, correct alignment to m anual lever shift quadrant is essential. • Low Oil Pressure - refer to LOW L IN E PRESSU RE. • Forw ard Clutch: a. Forw ard clutch does not apply - piston cracked; seals missing or damaged; clutch plates burned (Refer to B U R N E D C LU TC H PLATES). b. Pum p feed circuit-to-forw ard clutch oil seal rings missing or broken on pum p cover; leak in feed circuits; pump-to-case gasket m ispositioned or damaged; clutch drum ball check stuck or missing. • Low and Reverse Roller Clutch Assembly - broken spring, damaged cage or installed backwards. LIGHT T R U C K SE R V IC E M A N U A L A U TO M A TIC TRAN SM IS S IO N H ig h or Low O il Pressure (Refer to O IL PR ESSU R E C H EC K S) High Line Pressure • Vacuum Leak: a. Vacuum line disconnected. b. Leak in line from engine to m oldulator. c. Im proper engine vacuum. d. Leak in vacuum -operated accessory (hoses, vacuum advance, etc.). • M oldulator: a. Stuck m odulator valve. b. W ater in m odulator. c. Damaged, not operating properly. • D etent System - detent valve or cable stuck in detent position. • Valve Body: a. Pressure regulator a n d /o r boost valve stuck. b. Boost valve sleeve broken or defective. c. Incorrect pressure regulator valve spring. d. 2-3 shift control valve and sleeve installed in pressure regulator bore. e. Pressure regulator exhaust hole not drilled or blocked. Low Line Pressure • Low transmission oil level. • Defective vacuum m oldulator assembly. • Strainer Assembly: a. Blocked or restricted. b. G asket om itted or damaged. • Oil Pum p: a. G ear clearance, damaged, worn, gear installed backwards: b. Pum p-to-case gasket mispositioned. c. Defective pum p body a n d /o r cover. d. Bottom seal ring on pum p cover hub om itted or damaged. e. Prim ing valve in pum p om itted. • Valve Body: a. Pressure regulator or boost valve stuck. b. Pressure regulator valve spring, too weak. c. # 1 rubber ball omitted. d. Loose valve body bolts. e. Valve body spacer plate support omitted. f. Reverse and m odulator booster valve stuck. • Internal Circuit Leaks: a. Forw ard clutch leak (pressure low in Drive range, pressure norm al in N eutral (N ) and Reverse (R)). 1. Check pump oil seal rings. 2. Check forward clutch seals. b. D irect clutch leak (pressure low in Reverse (R), pressure norm al in other ranges). 1. Check direct clutch outer seal. 2. Check 1-2 accum ulator and 2-3 accum ulator pistons and rings for damage or missing. c. Interm ediate servo piston seal ring broken or omitted. • Case Assembly - check ball missing from cored passage in case face. 7A-19 No Pressure • • • • • Flashing blocking suction cavity in case. Prim ing valve in pum p omitted. Front pum p drive gear lugs sheared off. Vacuum m odulator valve omitted. Pum p to case gasket incorrectly installed. No Upshift • G overnor valve stuck (chips). • 1-2 shift control or shift valve stuck. • Nylon gear of governor assembly m utilated or broken. • G overnor locating pin in case loose. • 1-2 accum ulator piston ring omitted or broken. • Incorrect interm ediate clutch pack. • Interm ediate piston seals omitted or damaged. • G overnor inner weights jammed. Low Downshifts 3-2 and 2-1 (Full Detent) • • • • • • • Detent regulator valve stuck. D etent regulator valve spring seat omitted. Shift control or shift valves sticking. D etent linkage not hooked up. Incorrect vacuum setting. Defective governor. M odulator valve sticking. High Downshifts 3-2 and 2-1 (Full Detent) • D etent regulator valve sticking or stuck. • Defective governor assembly. • Shift control and shift valves sticking. No Drive in Drive Range • Forw ard clutch apply holes in pum p hub not drilled. • Clutch apply hole in forward clutch drum not drilled. • Lip seals of forward clutch piston om itted or damaged. • Steel relief ball in forward clutch drum om itted or not sealing. • Incorrect pressure plate (excessive clearance). • Rear roller clutch slipping or installed backwards. • D am aged shifter shaft (transmission not in drive range). • Input ring gear omitted. • M anual valve incorrectly installed. No Drive in Reverse (R) Range • • • • • • Reverse clutch pack snap ring omitted. D irect clutch apply holes in pum p hub not drilled. Direct clutch apply oil seal rings om itted or broken. Reverse apply holes in case not drilled or blocked. Incorrect clutch pack. M anual valve incorrectly installed. Low Lube Pressures • Bushings om itted in front of stator shaft I.D. 1-2 Shift - Full Throttle Only • D etent Valve - sticking or linkage misadjusted. • Vacuum Leak - vacuum line or fittings leaking. LIGHT TRUCK SE R V IC E M A N U A L 7A-20 A U T O M A T IC TRAN SM IS S IO N • Control Valve Assembly: a. Valve body gaskets - leaking, dam aged or incorrectly installed. b. D etent valve train stuck. c. 1-2 valve stuck closed (in downshifted position). • Case Assembly - refer to case porosity repair. First Speed Only - No 1-2 Shift • Detent (downshift) cable - binding. • G overnor Assembly: a. G overnor valve sticking. b. Driven gear loose, damaged or worn (check for pin in case and length of pin showing; also, check output shaft drive gear for nicks or rough finish if driven gear shows damage). • Control Valve Assembly: a. Valve body gaskets - leaking, damaged or incorrectly installed. b. G overnor feed channels blocked. c. 1-2 shift valve train stuck closed (in downshifted position). • Interm ediate Clutch: a. Clutch piston seals - missing, improperly installed or cut. b. Interm ediate roller clutch - broken spring or damaged cage. • Case: a. Porosity between channels. b. G overnor feed channel blocked; governor bore scored or worn, allowing cross pressure leak. First and Second Speeds Only - No 2-3 Shift • C ontrol Valve Assembly: a. Valve body gaskets - leaking, damaged or incorrectly installed. b. 2-3 shift valve train stuck closed (in downshifted position). • D irect Clutch: a. Pum p hub - direct clutch oil seal rings - broken or missing. b. Clutch piston seals - missing, im properly assembled or cut. c. Clutch plates burned (Refer to B U R N E D C L U TC H PLATES). No First Speed - Starts in Second Speed (Locks up in LI Range) Interm ediate Clutch: 1. Too m any plates in interm ediate clutch pack. 2. Incorrect interm ediate clutch piston. Drive in Neutral • M anual Linkage - misadjusted, (correct alignment in m anual lever shift quadrant is essential). • Internal Linkage - m anual valve disconnected or end broken. • Oil Pum p - line pressure leaking into forward clutch apply passage. • Forw ard Clutch - incorrect clutch plate usage or burned clutches (Refer to B U R N E D ■ ! r CH PLATES). N o M o tio n in R e v e r s e o r S lip s in R e v e r s e (Install pressure gage) • Low Oil Level - add oil. • M anual Linkage - m isadjusted (correct alignment in m anual lever shift quadrant is essential). • Low Oil Pressure - Refer to LOW L IN E PRESSU RE. • Control Valve Assembly: a. Valve body gaskets - leaking, damaged or incorrectly installed. b. 2-3 shift valve train stuck open (in upshifted position). • Interm ediate Servo - piston or pin stuck so interm ediate overrun band is applied. • Low and Reverse Clutch - piston outer seal damaged or missing. • D irect Clutch: a. O uter seal damaged or missing. b. C lutch plates burned (Refer to B U R N E D C LU TC H PLATES). • Forw ard Clutch - clutch does not release (will cause D R IV E in N EU TR A L). S lip s In All R a n g e s O r S lip s O n S t a r t (Install pressure gage) • Low Oil Level - add oil. • Low Oil Pressure - Refer to LOW L IN E PRESSURE. • Forw ard clutch: a. Clutch plates burned (Refer to B U R N E D C LU TC H PLA TES). b. Pum p cover oil seal rings broken or worn. • Case - cross leaks or porosity. S lip p in g 1-2 S h if t (Install pressure gage) • Low Oil Level - add oil. • Low Oil Pressure - Refer to LOW L IN E PRESSURE. • 2-3 A ccum ulator - oil ring damaged or missing. • 1-2 A ccum ulator - oil ring dam aged, missing or case bore damaged. • Pum p-to-Case G asket - m ispositioned or damaged. • Interm ediate Clutch: a. Piston seals damaged or missing. b. Clutch plates burned (Refer to B U R N E D CLU TC H PLATES). • Case - porosity between channels. S lip p in g 2-3 S h if t (Install pressure gage) • Low Oil Level - add oil. • Low Oil Pressure - Refer to LOW L IN E PRESSURE. • D irect Clutch: a. Piston seals leaks, dam aged or missing. b. Clutch plates burned (Refer to B U R N E D C LU TC H PLATES). c. Inspect for proper num ber and type of clutch plates. LIGHT T R U C K SE R V IC E M A N U A L A U TO M A TIC TRAN SM IS S IO N No Detent (Wide Open Throttle^ • Case - refer to case porosity repair. Rough 1-2 Shift Downshift (Install pressure gage) • High Oil PRESSURE. 7A-21 Pressure - Refer to H IG H L IN E • 1-2 A ccum ulator: a. Oil rings damaged. b. Piston stuck. c. Broken or missing spring. d. Bore damaged. • Interm ediate C lutch - check for burned and num ber (type) of plates. • Case: a. Check for correct num ber and location of check balls. b. Porosity between channels. Rough 2-3 Shift (Install pressure gage) • High Oil Pressure PRESSU RE. • 2-3 Accum ulator: - Refer to H IG H L IN E a. Oil ring damaged. b. Piston stuck. c. Broken or missing spring. d. Piston bore damaged. No Engine Braking in L2 (Install pressure gage) • Low Oil Pressure - pressure regulator a n d /o r boost valve stuck. • Interm ediate Servo and 2-3 A ccum ulator: a. Servo or accum ulator oil rings or bores leaking or damaged. b. Servo piston stuck or cocked. • D etent cable or retainer not adjusted properly. • D etent cable disconnected at transmission or throttle linkage. • Valve Body: a. D etent valve sticks. b. D etent regulator valve sticks. c. Incorrect spacer plate or gasket. High or Low Shift Points (Install pressure gage) • Oil Pressure: a. Engine Vacuum - check at transmission end of m odulator pipe. b. Check vacuum line connections at engine and transmission. c. Vacuum m odulator assembly and valve and pressure regulator valve train. • Governor: a. Valve sticking. b. Feed holes restricted or leaking. • D etent Valve and Linkage - stuck open (will cause high shift points). • Control Valve Assembly: a. 1-2 shift valve train sticking. b. 2-3 shift valve train sticking. • Case - refer to case porosity repair. Won't Hold in PARK(P) • Interm ediate O verrun Band - interm ediate overrun band broken or burned (look for cause), not engaged or servo pin. • M anual Linkage - misadjusted (correct alignment in m anual lever shift quadrant is essential). • Internal Linkage: a. Inner lever and actuating rod assembly - defective or improperly installed. b. Parking pawl - broken or inoperative. c. Parking lock bracket loose, burred or rough edges or incorrectly installed. d. Parking pawl disengaging spring missing, broken or incorrectly hooked. No Engine Braking in L1 Transmission Noisy (Install pressure gage) • Low Oil Pressure - pressure regulator a n d /o r boost valves stuck. • M anual Low Control Valve Assembly - stuck. • Low and Reverse Clutch - piston inner seal damaged or missing. Before checking transm ission for noise, make certain that the noise is not coming from the water pump, alternator, power steering, etc. These components can be isolated by removing the proper belt and running the engine not more than two m inutes at one time. No Part Throttle Downshift (Install pressure gage) • Oil Pressure - vacuum m odulator assembly, m odulator valve or pressure regulator valve train (other m alfunctions may also be noticed). • D etent Valve and Linkage - sticks, disconnected or broken. • 2-3 shift valve - stuck. P a rk , N e u tr a l a n d all D riv in g R a n g e s • Pum p Cavitation: a. Low oil level. b. Plugged or restricted strainer. c. Strainer-to-valve body gasket damaged. d. Porosity in valve body intake area. e. W ater in oil. f. Porosity or voids at transmission case (pum p face) intake port. g. Pump-to-case gasket off location. • Pum p Assembly: LIGHT TR U C K SE R V IC E M A N U A L 7A-22 A U T O M A T IC TRAN SM ISSIO N FORW ARD LOW/REV. CLUTCH CLUTCH LO W A N D ROLLER CLUTCH INTERMEDIATE CLUTCH INTER. O VERRU N ROLLER CLUTCH INTERMEDIATE BA ND DIRECT CLUTCH NEUTRAL OFF In e ffe c tiv e O FF OFF OFF OFF In e ffe c tiv e DRIVE, First Gear O FF In e ffe c tiv e O FF O FF ON OFF Locked DRIVE, Second Gear ON Locked OFF OFF ON O FF F r e e - W h e e lin g DRIVE, Third Gear ON F r e e - W h e e lin g OFF ON ON OFF F r e e - W h e e lin g Li OFF In e ffe c tiv e OFF O FF ON ON Locked L2 ON Locked ON O FF ON O FF F r e e - W h e e lin g REVERSE OFF In e ffe c tiv e OFF ON OFF ON In e ffe c tiv e Fig. 7A-1 1 -3 5 0 C lutch A p p ly C hart a. G ears damaged. b. Driving gear assembled backwards. c. Crescent interference. d. Oil seal rings dam aged or worn. • Converter: a. Loose flexplate-to-converter bolts. b. Converter damage. c. W ater in oil (causes whine). F irs t, S ec o n d a n d /o r R e v e rs e G e a r Planetary G ear Set: 1. G ears or thrust bearings damaged. 2. Input or output ring gear damaged. D u rin g A c c e le ra tio n - A n y G e a r • Transm ission or cooler lines grounded to underbody. • M otor m ounts loose or broken. S q u e a l a t L o w V e h ic le S p ee d Speedometer driven gear lubrication or replacement. shaft seal - requires LIG HT T R U C K SE R V IC E M A N U A L PROBLEM CAR R O A D TEST LEGEND X -P R O B LE M * —@ " O " AREA VS VACUUM O -B A L L S / #2/3/4 CA US E ONLY ONLY L-LO C K E D S-STUCK PO SS IB LE CA US E L O W O I L L E V E L / W A T E R IN O IL VACUUM LEAK M O D ULA TO R & /O R VALVE S T R A IN E R & /O R GASKET G O V E R N O R - V A LV E /S C R E E N V A L V E B O D Y -G A S K E T /PLAT E PRES R E G . & / O R BOOS T V A L V E BALL (# 1 ) SHY 1-2 S H I F T V A L V E 2 -3 S H I F T V A L V E M A N U A L LOW C O N T 'L VALVE D E TE N T V A L V E & LIN K AG E D E T E N T REG. V A L V E 2-3 A C C U M U L A T O R _________ PO RO SITY/CROSS LEAK P U M P —G E A R S P R I M I N G V A L V E SH Y COOLER V A LVE LEAK C L U T C H S E A L R IN G S PO RO U S /C R O S S L E A K G A S K E T SCREEN-PRESSURE B A N D - I N T E R M . O.R. C A S E -P O R O U S /X LEAK 1 2 ACCUMULATOR IN T E R M E D . SERVO F O R W A R D C L U T C H ASS Y D I R E C T C L U T C H ASS Y I N T E R M E D . C L . A S S 'Y L & R E V . C L . A S S 'Y I N T . R O L L E R C L . ASS Y L. & R. R O L L E R C L . AS S' Y AUTOMATIC TRANSMISSION M A N U A L V A L V E /L IN K A G E PA RK P A W L /L IN K A G E C O N V E R T E R A S S' Y 7A-23 G E A R SE T & B E A R I N G S 7A-24 AUTOMATIC TRANSMISSION [COOLER IN; [COOLER OUT; COOLER CONV APPLY! INTERM EDIATE CLUTCH ACCUMULATOR LUBE Fig. 7 A -13 -3 5 0 PUMP PRESSURE! conv r e l: MOD CONV F D l zn 23 c l : REVZ INTERM EDIATE SERVO Hydraulic PRESSURE REGULATOR CONVERTER CLUTCH VALVE s u c t io n : d r iv e ; Circuit - TCC DRIVE GOVERNOR Applied SUMP SWITCH ASM PRESSURE SCREEN ;MOD OR DET M ANUAL VALVE DRIVE 2 3 SHIFT VALVE MAN LOW CONT: DETENT PRESSURE REGULATOR M ANUAL LOW CONTROL VA LV E ;g o v ; MAN LOW CONT: d r iv e MODULATOR 1 2 SERVO: ; A U T O M A T IC TRAN SM IS S IO N 7A-25 ON V EH IC LE S E R V IC E TRANSMISSION REPLACEMENT 12. Remove transm ission to engine mounting bolts and remove oil filler tube at transmission. (All Except K Model) If necessary, the catalytic converter may have to be disconnected to provide adequate clearance for transmission removal. This procedure will include removal of the converter support bracket. 1. Before raising the vehicle, disconnect the negative battery cable detent downshift cable at carburetor and release the parking brake. 2. Raise vehicle on hoist. 3. Remove propeller shaft. 4. D isconnect speedometer cable, detent downshift cable, m odulator vacuum line and oil cooler pipes at transm ission. 5. Disconnect shift control linkage. 6. Support transm ission with suitable transmission jack. 7. Disconnect rear m ount from frame crossmember. 8. Remove two bolts at each crossmember. Remove crossmember. end of frame 9. Remove converter under pan. 10. Remove converter-to-flexplate bolts, as shown in Fig. 7A-14. 11. Lower transmission until jack is barely supporting it. 13. Raise transmission to its norm al position, support engine with jack and slide transmission rearw ard from engine and lower it away from vehicle. Use suitable converter holding tool when lowering transm ission or keep rear of transmission lower than front so as not to lose converter. The installation of the transmission is the reverse of the removal with the following added step. Before installing the flexplate-to-converter bolts, make certain that the attaching lugs on the converter are flush with the flex plate and the converter rotates freely by hand in this position. Refer to Fig. 7A-14 for instructions on attaching the converter-toflexplate. This will insure proper converter alignment. After installation of transmission, lower vehicle and remove vehicle from hoist. Check linkage for proper adjustm ent. Check transmission fluid level. TRANSMISSION REPLACEMENT (K MODEL) 1. Disconnect battery cable. 2. Remove transm ission dipstick. 3. Disconnect detent downshift cable at carburetor. 4. Remove transfer case shift lever knob and boot. 5. Raise vehicle on hoist. 1. M O V E C O N VER TER FO R W A R D TO C O N T A C T A T T A C H IN G SURFACE O N FLEXPLATE PRIOR TO T IG H T E N IN G BOLTS. 2. A L IG N SLOT IN FLEXPLATE TH A T H A S A N ID E N T IF IC A T IO N HOLE N E A R IT, W IT H A N A T T A C H M E N T HOLE IN C O N VE R TE R . INSTALL BOLT A N D N U T A N D T IG H T E N TO SPECIFIED T O R Q U E . T IG H T E N ALL R E M A IN IN G BOLTS TO SP EC IFIED TO R Q U E AS THEY ARE INSTALLED. Fig. 7A-1 4~Typical T ransm ission M ounting, Net-Hole Design LIG HT TRU CK SE R V IC E M A N U A L 7A-26 A U T O M A T IC TRAN SM IS S IO N 6. Remove flexplate cover. 7. Remove torque converter to flexplate attaching bolts. Refer to Fig. 7A-14. Secure the converter. 8. D isconnect transm ission shift linkage and speedometer cable. 9. Remove engine crossunder pipe to m anifold bolts. 10. Disconnect vacuum m odulator line, line to filler tube clip and detent downshift cable to filler tube strap. 11. Disconnect detent downshift cable at the transmission. 12. D isconnect transm ission oil cooler lines at the transmission. 13. Remove transfer case adapter to crossm em ber bolts. W hen applicable, disconnect engine-to-transmission support strut rod from transmission. Refer to Fig. 7A-22. 14. Raise engine as necessary. 15. Remove crossm em ber bolts and remove crossmember. 16. Remove exhaust system hanger bolts. 17. D isconnect rear propeller shaft at transfer case. 18. D isconnect parking brake cable. 19. Disconnect exhaust system. (Tie aside.) 20. Disconnect front propeller shaft at front axle. (Tie aside.) 21. Support transm ission and transfer case w ith jack (use safety chains). 22. Remove transfer case to fram e bracket bolts. 23. Remove transm ission to engine bolts, remove transm ission and transfer case. 24. D isconnect transfer case-to-transm ission strut rod. Remove transfer case from transm ission (includes: new "O" ring seal). Refer to Fig. 7A-15. 25. Move transm ission to bench fixture. 26. D rain transmission. 27. Remove torque converter. 28. Remove and discard front pum p seal. Fig. 7A-1 6—In stallin g Oil Se a l into Extension H o u sin g 29. install. Refill transfer case. Reverse removal procedure to E X T E N S IO N H O U S IN G O IL S E A L Removal 1. Remove propeller shaft. 2. Pry out lip oil seal with screwdriver or small chisel. Installation 1. Drive a new oil seal into place with Installer J21426, as shown in Fig. 7A-16. 2. Install propeller shaft and adjust fluid level. S P E E D O M E T E R D R IV E N G E A R Removal 1. D isconnect speedometer cable. 2. Remove retainer bolt, retainer, speedometer driven gear and O-ring seal. Installation Installation of speedometer driven gear is the reverse of REM O V A L. Install new O-ring seal (if required) and adjust the fluid level. S P E E D O M E T E R D R IV E G E A R Removal 1. Raise vehicle and support transm ission with suitable transm ission jack. 2. Remove propeller shaft. 3. D isconnect speedometer cable. 4. D isconnect transm ission rear m ount from frame crossmember. 5. Remove two bolts at each end of frame cross member and remove crossmember. 6. Remove extension housing. 7. Install Special Tools J-2 1427-01 and J-8105 on output shaft and remove speedom eter drive gear. Remove retaining clip. LIGHT T R U C K SE R V IC E M A N U A L A U T O M A T IC TRAN SM IS S IO N 7A-27 MANUAL SHAFT TO CASE RETAINER SCREWDRIVER V Fig. 7 A - 1 8 -G o v e rn o r Cover Fig. 7 A -1 7 -R e m o v in g M a n u a l Shaft-to -C ase Retainer Installation In s ta lla tio n 1. Place speedometer drive gear retaining clip into hole in output shaft. 2. Align slot in speedom eter drive gear with retaining clip and install. 3. Install extension housing and tighten attaching bolts to 25 ft. lb. (33 N -m ) 4. Connect speedometer cable. 5. Install crossmem ber to frame and transmission. 6. Install propeller shaft. 7. Remove transmission jack and lower vehicle. Installation of parking linkage, selector lever and m anual shaft is the reverse of REM OVAL. Install new plug (if required), new lip oil seal (if required) and new gaskets. A djust the fluid level. MANUAL SHAFT, RANGE SELECTOR INNER LEVER AND PARKING LINKAGE ASSEMBLIES Removal 1. Refering to draining procedures, drain transmission fluid from oil pan. 2. A fter oil pan and strainer have been removed, remove valve body assembly. D iscard gaskets. 3. Remove manual shaft-to-case retainer and unthread jam nut holding range selector inner lever to m anual shaft. Refer to Fig. 7A-17. 4. Remove jam nut and remove m anual shaft from range selector inner lever and case. Do not remove m anual shaft lip oil seal unless replacem ent is required. 5. Remove parking pawl actuating rod and range selector inner lever from case. 6. Remove bolts and parking lock bracket. 7. Remove parking pawl disengaging spring and, if necessary to replace parking pawl or shaft, clean up bore in case and remove parking pawl shaft retaining plug, park pawl shaft and pawl. Before installing the propeller shaft, liberally lubricate splines of the transmission yoke with a Lithium soap base lubricant. The lubricant should seep from the vent hole (rear cap of yoke) when installing yoke on transmission output shaft. It is essential that the vent hole is not obstructed. GOVERNOR Rem oval 1. Raise vehicle and disconnect speedometer cable at transmission. 2. Remove governor cover, as shown in Fig. 7A-18. NOTICE: Be careful not to damage cover. 3. Remove governor. Inspect weights and valve for freeness. In s ta lla tio n 1. Install governor. 2. Apply anerobic sealant to cover, then install governor cover using a brass drift around the outside flange of the cover. NOTICE: Do not distort cover on installation. 3. Install a retainer wire. NOTICE: Be sure to install a bail wire retainer, to prevent loss of cover, which could result in damage to the transmission. LIG HT TRU CK SE R V IC E M A N U A L 7A-28 A U T O M A T IC TRAN SM IS S IO N GOVERNOR PRESSURE SWITCH n SERVO TORQUE CONVERTER * O ” R IN G SEAL SOLENOID SWITCH iX B VA C U U M MODULATO R £ J A AUXILIARY VALVE BODY MAIN VALVE BODY 'ELECTRICAL CONNECTOR Fig. 7 A -1 9 ~ R e m o v in g V a cu u m M o d u la to r Fig. 7A -2 0 ~ D e te n t S p r in g /V a lv e B o d y 4. Connect speedom eter cable, lower vehicle and check transm ission fluid level. V A C U U M M O DULATO R AND M ODULATO R VALVE ASSEM BLY Removal 1. D isconnect vacuum hose from vacuum m odulator stem and remove vacuum m odulator attaching screw and retainer. 2. Remove m odulator assembly and its O-ring seal from case. Refer to Fig. 7A-19. 3. Remove m odulator valve from case. Installation Installation of the m odulator and m odulator valve is the reverse of REM O V A L. Install a new O-ring seal and adjust the fluid level. 4. Remove tool and install oil pan bolts. Installation Installation of the valve body assembly is the reverse of REM O V A L. Install new gaskets to strainer and oil pan and adjust the fluid level. 1-2 A C C U M U L A T O R Removal 1. Remove two transm ission oil pan bolts below the 1-2 accum ulator cover. Install J-23069 in place of bolts removed. 2. Press in on cover and remove retaining ring. 3. Remove cover "O" ring seal, spring and accum ulator, as shown in Fig. 7A-21. 1-2 VALVE BODY ASSEM BLY Removal 1. Refering to draining procedures, drain transm ission fluid from oil pan. 2. A fter oil pan and strainer, have been removed, discard gaskets. 3. Remove detent spring and roller assembly from valve body and remove valve body-to-case bolts. Refer to Fig. 7A-20. 4. Remove valve body assembly while disconnecting m anual control valve link from range selector inner lever and removing detent control valve link from the detent actuating lever. 5. Remove m anual valve and link assembly from valve body assembly. Fig. 7 A -2 1 -In te rm e d ia te Clutch A ccu m u la to r Com ponents L IGHT T R U C K SE R V IC E M A N U A L A U T O M A T IC TRAN SM IS S IO N 7A-29 2. Position spring, "O" ring seal and cover in place. 3. Press in on cover with J-23069 and install retaining ring. 4. Remove tool and install oil pan bolts. SUPPORT STRUT ROD Replacement The transm ission support strut rod attachm ent is shown in Fig. 7A-22. Remove the two bolts when replacing the strut rod. W hen removing the transmission, it is only necessary to remove the bolt at the transmission end of the strut rod. OIL COOLER PIPES If replacem ent of transm ission steel tubing cooler pipes is required, use only double w rapped and brazed steel tubing meeting G M specification 123M or its equivalent. U nder no condition use copper or alum inum tubing to replace steel tubing. Those m aterials do not have satisfactory fatique durability to w ithstand norm al vehicle vibrations. Fig. 7 A -2 2 ~ T ra n sm issio n S u p p o rt Strut Rod In s ta ll 1. Install 1-2 accum ulator piston. R otating piston slightly when installing will help to get rings started in bore. Steel tubing should be flared using the upset (double lap) flare m ethod which is detailed in Section 5. 4 0 0 A U T O M A T IC T R A N S M IS S IO N INDEX G eneral D escription.......................................................... M aintenance and A d ju stm en t........................................ Checking Transmission M o u n t.................................... Transm ission F lu id ......................................................... Colum n Shift Linkage A dju stm en t............................. D etent Switch A d justm ent............................................ N eutral Start Backup Lam p Switch A djustm ent.... Vacuum Regulator V alve............................................. D iagnosis.............................................................................. Diagnosis Sequence......................................................... Oil Checking P ro ced u re................................................ Oil Leak D iagnosis......................................................... Oil Pressure C h e c k ......................................................... Case Porosity R e p a ir...................................................... Vacuum M odulator D iagnosis..................................... M anual L inkage............................................................... 7A -29 7A -31 7A-31 7A-31 7A-32 7A-33 7A-33 7A-33 7A-34 7A -34 7A-34 7A-34 7A-34 7A-35 7A-35 7A -36 Trouble D iagnosis.............................................................7A-36 C lutch Apply C h a rt........................................................ .7A-41 H ydraulic C ircu it..............................................................7A-42 On Vehicle Service..............................................................7A-43 Transm ission R eplacem ent........................................... .7A-43 R ear S eal.............................................................................7A-44 G o v e rn o r.............................................................................7A-44 M odulator and M odulator V alve................................ .7A-44 Parking L inkage............................................................... .7A-44 C ontrol Valve B ody........................................................ .7A-45 Pressure Regulator V alve...............................................7A-45 Oil Cooler Pipes............................................................... .7A-46 O ther Service O perations.................................................7A-46 Specifications....................................................................... ..7A-47 Special T o o ls....................................................................... ..7A-48 G E N E R A L D E S C R IP T IO N The 400 autom atic transm ission is a fully autom atic unit consisting prim arily of a 3-element hydraulic torque converter and a com pound planetary gear set. Three m ultiple-disc clutches, one gear unit, one roller clutch, and two bands provide the friction elements required to obtain the desired function of the com pound planetary gear set. The torque converter couples the engine to the planetary gears through oil and provides hydraulic torque m ultiplication when required. The com pound planetary gear set produces three forward speeds and reverse. The 3-element torque converter consists of a pum p or driving member, a turbine or driven member, and a stator assembly. The stator is m ounted on a one-way roller clutch which will allow the stator to turn clockwise but not counter-clockwise. The torque converter housing is filled with oil and is attached to the engine crankshaft by a flexplate and always rotates at engine speed. The converter pum p is an integral LIGHT T R U C K SE R V IC E M A N U A L 7A-30 A U T O M A T IC TRAN SM IS S IO N Fig. 7 A -3 0 - 4 0 0 A utom atic T ra n sm issio n C ro ss-Se ctio n V ie w part of the converter housing, therefore the pum p blades, rotating at engine speed, set the oil within the converter into motion and direct it to the turbine, causing the turbine to rotate. As the oil passes through the turbine it is traveling in such a direction that if it were not redirected by the stator it would hit the rear o f the converter pum p blades and impede its pum ping action. So at low turbine speeds, the oil is redirected by the stator to the converter pum p in such a m anner th at it actually assists the converter pum p to deliver power or m ultiply engine torque. As turbine speed increases, the direction of the oil leaving the turbine changes and flows against the rear side of the stator vanes in a clockwise direction. Since the stator is now impeding the sm ooth flow of oil, its roller clutch releases and it revolves freely on its shaft. Once the stator becomes inactive, there is no further m ultiplication of engine torque w ithin the converter. A t this point, the converter is merely acting as a fluid coupling as both the converter pum p and turbine are being driven at approxim ately the same speed or at one-to-one ratio. A hydraulic system pressurized by a gear type pum p provides the working pressure required to operate the friction elements and autom atic controls. External control connections to transm ission are: M anual Linkage - To select the desired operating range. Engine Vacuum - To operate a vacuum m odulator unit. 12 solenoid. Volt Electrical - To operate an electrical detent A vacuum m odulator is used to automatically sense any change in the torque input to the transmission. The vacuum m odulator transm its this signal to the pressure regulator for line pressure control, to the 1-2 accum ulator valve, and to the shift valves so th at all torque requirem ents of the transm ission are met and sm ooth shifts are obtained at all throttle openings. The detent solenoid is activated by an electric switch on the carburetor. W hen the throttle is fully opened, the switch on the carburetor is closed, activating the detent solenoid and causing the transm ission to downshift for passing speeds. The selector quadrant has six selector positions: P, R, N, D, L2, L I. P. P A R K position positively locks the output shaft to the transm ission case by means of a locking pawl to prevent the vehicle from rolling in either direction (not on CL model). The engine may be started in Park position. R. REV ERSE enables the vehicle to be operated in a reverse direction. N. N eutral postion enables the engine to be started and run w ithout driving the vehicle. D. D R IV E Range is used for all norm al driving conditions and maxim um economy. Drive Range has three gear ratios, from the starting ratio to direct drive. Detent downshifts are available by depressing the accelerator to the floor. LIGHT TR U C K SER VIC E M A N U A L A U T O M A T IC T R A N SM IS S IO N L2. L2 Range has the same starting ration as Drive Range, but prevents the transm ission from shifting ration when extra perform ance is desired. L2 Range can also be used for engine braking. L2 Range can be selected at any vehicle speed, and the transmission will shift to second gear and remain in second until the vehicle speed or the throttle are changed to obtain first gear operation in the same m anner as in D Range. 7A-31 L I. L I Range can be selected at any vehicle speed, and the transm ission will shift to second gear and rem ain in second until vehicle is reduced to approxim ately 40 M PH (60 km /h ), depending on axle ratio. L I Range position prevents the transm ission from shifting out of first gear. NOTICE: It is very im portant that any com m unication concerning the transm ission always contain the transm ission code and vehicle identification number. M A IN T E N A N C E A N D A D J U S T M E N T S CHECKING TRANSMISSION MOUNT Raise the vehicle on a hoist. Push up and pull down on the transm ission extension while observing the transm ission m ount. If the rubber separates from the metal plate o f the m ount or if the extension moves up but not down (m ount bottom ed out), replace the m ount. If there is relative m ovement between a m etal plate of the m ount and its attaching point, tighten the screws or nuts attaching the m ount to the transm ission or crossmember. determined by m ark on the dipstick rather than by amount added. Use only D E X R O N ® I I autom atic transm ission fluid or its equivalent. An early change to a darker color from the usual red color a n d /o r a strong odor that is usually associated with overheated transm ission fluid is norm al, and is not a positive sign of required m aintenance or transm ission failure. Checking Procedure and Adding Fluid TRANSMISSION FLUID To determ ine proper fluid level at norm al operating tem perature of 180°F (82°C), proceed as follows: Fluid Level and Capacity 1. Position vehicle on a level surface, place selector lever in P A R K (P), apply parking brake and have engine running at norm al idle. The fluid level indicator is located in the filler tube at the right rear of the engine. To bring the fluid level from the A D D m ark to the F U L L m ark requires one pint of fluid. Fluid level should be checked at every engine oil change. Fluid level should be to the F U L L m ark with the transm ission fluid at norm al operating tem perature of 180°F, (82°C). W ith warm fluid at room tem perature o f 70°F (21°C), the level will be 3 /8 in. (9 m m ) below the A D D m ark on the dipstick. The norm al operating tem perature is obtained only after at least 15 miles o f highway type driving or the equivalent of city driving. A pproxim ately 9 pints (4 L) of fluid are required to refill transmission after oil pan has been drained. The fluid capacity of the 400 transm ission and converter assembly is approxim ately 22 pints (10 L) but correct level is COOL — HOT (65°-85° F.) ( 1 9 0 -2 0 0 (18°-29°C.) F.) (88°-93° C.) I~H 1 PT FULL W ARM NOTE: DO NOT OVERFILL. IT TAKES ONLY ONE PINT TO RAISE LEVEL FROM ADD TO FULL WITH A HOT TRANSMISSION. Fig. 7A-3 1~Dipstick M arkings 2. Remove fluid level indicator, wipe it clean and reinstall fully until cap seats. 3. Remove indicator and reading of fluid level should be at full "F" m ark. 4. If additional fluid is required, add D E X R O N ® II autom atic transm ission fluid or its equivalent to "F" m ark on indicator. If the vehicle cannot be driven sufficiently to bring the transm ission to operating tem perature and it becomes necessary to check the fluid level, the transm ission may be checked at room tem perature of 70°F (21°C) as follows: 1. Position selector lever in P A R K (P), apply parking brake and start engine. D O N O T R A C E E N G IN E . Move selector lever through each range. 2. Im m ediately check fluid level with selector lever in Park, engine running and vehicle on LEV EL surface. Fluid level on indicator should be 3 /8 in. (9 mm ) below the "A D D " mark. 3. If additional fluid is required, add enough fluid to bring level to 3 /8 in. (9 mm) below the A D D m ark on the dipstick. If transm ission fluid level is correctly established at 70°F (21°C), it will appear at the F U L L m ark on the dipstick when the transm ission reaches its norm al operating tem perature of 180°F (82°C). NOTICE: D O N O T O V ER FILL , as foaming and loss of fluid through the vent pipe m ight occur as fluid heats up. If fluid is too low, especially when cold, complete loss of drive may result which can cause transm ission failure. LIGHT TR U C K SE R V IC E M A N U A L 7A-32 A U T O M A T IC TRAN SM ISSIO N Draining and Refilling Transmission Oil Pan The oil pan should be drained and filter replaced and fresh fluid added to obtain the proper level on indicator, at the intervals detailed in section O-B of this m anual. For vehicles subjected to heavy city traffic during hot weather, or in commercial use, when the engine is regularly idled for prolonged periods or when vehicle is used for towing, oil pan should be drained and filter replaced m ore frequently. Refer to Section O-B. D rain fluid immediately after operation before it has had an opportunity to cool. CAUTION: Transmission fluid temperature can exceed 350°F (177°C). 1. Raise vehicle and support transm ission with suitable jack at transmission. 2. W ith fluid receptacle placed under transm ission oil pan, remove oil pan attaching bolts from front and side of pan. 3. Loosen rear pan attaching bolts approxim ately four (4) turns. 4. Carefully pry transm ission oil pan loose with screwdriver, allowing fluid to drain. 5. Remove rem aining screws and remove oil pan and gasket. D iscard gasket. 6. D rain fluid from oil pan. Clean pan with solvent and dry thoroughly w ith clean compressed air. 7. Remove oil filter retainer bolt, oil filter assembly, O-ring seal from intake pipe and discard the filter and Oring seal. 8. Install new O-ring seal on intake pipe and install new filter on pipe assembly. 9. W ith O-ring seal on intake pipe, install pipe and filter assembly, attaching filter to the control valve assembly with its retainer bolt, torquing to 10 ft. lb. (13 N*m). 10. Install new strainer-to-valve body gasket, strainer and two (2) screws. 11. Install new gasket on oil pan and install oil pan. Tighten its 13 attaching bolt and washer assemblies to 12 ft. lb. (16 N*m). 12. Lower vehicle add approxim ately 5 pints U.S. measure (4 pints Im perial measure) of D E X R O N ® II autom atic transm ission fluid or its equivalent through filler tube. 13. W ith selector lever in P A R K (P) position, apply hand brake, start engine and let idle (carburetor off fast idle step). DO N O T R A C E E N G IN E . 14. Move selector lever through each range and, with selector lever in P A R K (P) range, check the fluid level. 15. A dd additional fluid to bring level to 1/4 in. (6.35 mm) below the A D D m ark on the dipstick. CAUTION: Do not overfill. Foaming can result if overfilled. Adding Fluid to Fill Dry Transmission and Converter Assembly In cases of transm ission overhaul, when a complete fill is required, including converter (approxim ately 22 pints (10 L), proceed as follows: 1. A dd 9 pints (4 L) of transm ission fluid through filler tube. 2. W ith m anual control lever in P A R K (P) position, start engine and place on cold idle cam. DO N O T R A C E E N G IN E . M ove m anual control lever through each range. 3. Im m ediately check fluid level with selector lever in P A R K (P), engine running and vehicle on LEVEL surface and add additional fluid to bring level to 3/8-in. (9 mm) below the "A D D " m ark on the dipstick. D o not overfill. SHIFT CONTROLS Column Shift Linkage - CK and P Series (Figs. 7A-32 and 7A-33) 1. The shift tube and lever assembly m ust be free in the m ast jacket. See Section 3B for alignm ent of steering colum n assembly if necessary. 2. To check for proper shift linkage adjustm ent, lift the transm ission selector lever tow ards the steering wheel. Allow the selector lever to be positioned in Drive (D) by the transm ission detent. D o not use indicator pointer as a reference to position the selector lever. W hen perform ing linkage adjustm ent, pointer is adjusted last. 3. Release the selector lever. The lever should be inhibited from engaging low range unless the lever is lifted. 4. Lift the selector lever tow ards the steering wheel and allow the lever to be positioned in N eutral (N ) by the transm ission detent. 5. Release the selector lever. The lever should now be inhibited from engaging reverse range unless the lever is lifted. 6. A properly adjusted linkage will prevent the selector from moving beyond both the neutral detent, and the drive detent unless the lever is lifted to pass over the mechanical stop in the steering column. LIGHT TR U C K SE R V IC E M A N U A L A U T O M A T IC TRAN SM IS S IO N 7A-33 PLUNGER PLUNGER TRANSMISSION CONTROL SWITCH P30 ( 42 ) SERIES PLUNGER CK SERIES P30 Fig. 7A-34--Detent D ow n sh ift Sw itch 7. If adjustm ent is required, remove screw (A) and spring w asher from swivel (B). 8. Set transm ission lever (C) in N eutral position by moving lever counter-clockwise to L I detent and then clockwise three (3) detent positions to N eutral (N). 9. Position transm ission selector lever in N eutral position as determined by the m echanical stop in steering colum n assembly. Do not use the indicator pointer as a reference to position the selector lever. W hen perform ing linkage adjustm ent, pointer is adjusted last. 10. Assemble swivel, spring washer and screw to lever assembly (D ) and tighten screw to 20 ft. lb. (27 N*m). 11. Readjust indicator needle if necessary to agree with the transm ission detent positions. Refer to Section 3B. 12. Readjust neutral start switch if necessary to provide the correct relationship to the transm ission detent positions. Refer to Section 8. 13. Check operation (C K Series): DETENT DOWNSHIFT SWITCH 1. Install switch as shown in Fig. 7A-34. 2. A fter installing the switch, press the switch plunger as far forward as possible. This presets the switch for adjustm ent. The switch will then adjust itself w ith the first wide open throttle application of the accelerator pedal. NEUTRAL START BACKUP LAMP SWITCH ADJUSTMENT The neutral start backup lamp switch m ust be adjusted so th at the car will start in the park or neutral position, but will not start in the other positions. For replacem ent and adjustm ent refer to Section 8 of this m anual. VACUUM REGULATOR VALVE-ADJUSTMENT W hen the 400 autom atic transmission is used w ith a diesel engine, the vacuum source for operation of the vacuum m odulator is through a vacuum regulator valve. This valve is m ounted on the high pressure fuel pum p, and should be adjusted as detailed in Section 6A6 of this manual. a. W ith key in "R un" position and transmission in "Reverse (R)" be sure that key cannot be removed and that steering wheel is not locked. b. W ith key in "Lock" position and shift lever in "Park (P)", be sure th at key can be removed, th at steering wheel is locked, and th at transm ission rem ains in "P ark (P)" when steering colum n is locked. NOTICE: Any inaccuracies in the above adjustm ents may result in prem ature failure of the transm ission due to operation without controls in full detent. Such operation results in reduced oil pressure and in turn partial engagement of the affected clutches. Partial engagement of the clutches with sufficient pressure to cause apparent norm al operation of the vehicle will result in failure of the clutches or other internal parts after only a few miles of operation. LIGHT T R U C K SE R V IC E M A N U A L 7A-34 A U T O M A T IC TRAN SM ISSIO N D IA G N O S IS DIAGNOSIS SEQUENCE Before attem pting to correct an oil leak, the actual source of the leak m ust be determined. In m any cases, the source of the leak can be deceiving due to "wind flow" around the engine and transmission. The suspected area should be wiped clean of all oil before inspecting for the source of the leak. Red dye is used in the transm ission oil at the assembly plant and will indicate if the oil leak is from the transmission. The use of a "Black Light" to locate the point at which the oil is leaking is helpful. Com paring the oil from the leak to that on the engine or transm ission dipstick, when viewed by black light, will determ ine the source of the leak - engine or transmission. Oil leaks around the engine and transm ission are generally carried tow ard the rear of the car by the air stream. F or example, a transm ission oil fill pipe to case leak will sometimes appear as a leak at the rear of the transm ission. In determ ining the source of a leak, proceed as follows: 1. Degrease underside of transmission. 2. R oad test to get unit at operating tem perature. (180 degrees F - 68 degrees C). 3. Inspect for leak w ith engine running. 4. W ith engine off, check for oil leaks due to the raised oil level caused by drain back. b. R ear seal assembly dam aged or im properly installed. c. Extension to case, gasket damage or im properly installed. d. Porous casting. See paragraph C. e. O utput shaft "O" ring damaged. 3. Case Leak a. Filler pipe seal dam aged or missing; misposition of filler pipe bracket to engine "loading" one side of seal. b. M odulator assembly "O" ring seal dam aged or im properly installed. c. Electrical connector "O" ring seal dam aged or im properly installed. d. G overnor cover bolts not torqued, gasket damaged or leak between case face and gasket. e. Speedometer gear "O" ring damaged. f. M anual shaft lip seal dam aged or improperly installed. g. Parking pawl shaft cup plug damaged, im properly installed. h. Line pressure band release tap plug loose. i. Vent pipe (Refer to item 5). j. Porous casting. See subparagraph C. 4. Leak at F ront of Transm ission a. F ront pum p seal leaks. 1. Seal lip cut. Check converter hub for nicks, etc. 2. Bushing moved forward and damaged. 3. G arter spring missing from seal. b. F ront pum p attaching bolts loose or bolt seals damaged or missing. c. F ront pum p housing "O" ring damaged or cut. d. Converter leak in weld area. e. Porous casting (pump). 5. Oil Comes O ut Vent Pipe a. Transm ission over-filled. b. W ater in oil. c. Foreign m atter between pum p and case or between pum p cover and body. d. Case - porous, front pum p cover m ounting face shy of stock near breather. Refer to subparagraph C. e. Pum p to case gasket mispositioned. f. Incorrect dipstick. g. Cut "O" ring or grom m et on filter. h. Pum p - shy of stock on m ounting faces, porous casting, breather hole plugged in pum p cover. Possible Points of Oil Leak FLUID PRESSURE CHECK 1. Check and correct oil level. 2. Check detent switch. 3. Check and correct vacuum line and fittings. 4. Check and correct m anual linkage. 5. Install oil pressure gage. 6. R oad test car. a. R oad test using all selective ranges, noting when discrepancies in operation or oil pressure occur. b. A ttem pt to isolate the unit or circuit involved in the malfunction. c. If engine perform ance indicates an engine tune up is required, this should be perform ed before road testing is completed or transm ission correction attem pted. Poor engine perform ance can result in rough shifting or other malfunctions. FLUID CHECKING PROCEDURES Refer to M aintenance and A djustm ent section for fluid checking procedure. FLUID LEAK DIAGNOSIS Determining Source of Oil Leak 1. a. b. c. 2. a. Transm ission Oil Pan Leak A ttaching bolts not correctly torqued. Im properly installed or dam aged pan gasket. Oil pan gasket m ounting face not flat. Case Extension A ttaching bolts not correctly torqued. Road or Normal Operating Conditions W hile road testing with the transm ission oil pressure gage attached and the vacuum m odulator tube connected , the transm ission pressure should check approximately as shown on Figure 7A-35. LIGHT TR U C K SE R V IC E M A N U A L A U T O M A T IC TRAN SM ISSIO N M inim um M axim um 145 psi 155 psi M inim um M axim um L 2-2nd G e a r - S te a d y ro a d lo ad at a p p ro x im a te ly 25 m p h G ear S e le c to r L ever P o sitio n 7A-35 1st 2nd 3rd D rive ( “ Z e ro ” th r o ttle to fu ll th r o t t l e .................................. ................ 60 150 3rd R everse D rive R an g e, Z ero T h r o ttle a t 30 m p h ............... R ev. (Z e ro to fu ll th r o ttle ........................................ ............... ................ 60 95 260 Fig. 7A -35--Fluid Pressure C h e c k - R oad or N orm al O p eratin g C o n d itio n s Vehicle Stationary - Engine at 1 2 0 0 RPM VACUUM MODULATOR DIAGNOSIS W ith the transmission oil pressure gage attached and the vacuum m odulator tube disconnected , the transm ission pressures should check approxim ately as shown in Fig. 7A-36. A defective vacuum m odulator can be determ ined by performing the following procedures. Vehicle Stationary - Engine at 1 0 0 0 RPM W ith the transm ission oil pressure gage attached and the vacuum m odulator tube connected for norm al m odulator operation, the transm ission pressure should check approxim ately as shown in Fig. 7A-37. Pressures are not significantly affected by altitude or barom etric pressure when the vacuum m odulator tube is connected. Case Porosity Repair External leaks caused by case porosity have successfully been repaired with the transm ission in the vehicle by using the following recom m ended procedures: 1. R oad test and bring the transm ission to operating tem perature, approxim ately 180 degrees (82°C). 2. Raise vehicle on hoist or jack stand, engine running and locate source of oil leak. Check for leak in all operating positions. Use of a m irror is helpful in finding leaks. 3. Shut engine off and thoroughly clean area to be repaired with a cleaning solvent and a brush air dry. 4. Using instructions of the m anufacturer, mix a sufficient am ount of epoxy to m ake repair. Observe cautions of m anufacturer in handling. 5. W hile the transm ission case is still H O T apply the epoxy to the area to be repaired. A clean, dry soldering acid brush can be used to clean the area and also to apply the epoxy cement. M ake certain the area to be repaired is fully covered. 6. Allow cement to cure for three hours before starting engine. 7. Road test and check for leaks. Vacuum Diaphragm Leak Check Insert a pipe cleaner into the vacuum connector pipe as far as possible and check for the presence of transmission oil. If oil is found, replace the modulator. Gasoline or w ater vapor may settle in the vacuum side of the m odulator. If this is found without the presence of oil, the m odulator should not be changed. Atmospheric Leak Check Apply a liberal coating of soap bubble solution to the vacuum connector pipe seam, the crimped upper to lower housing seam, and the threaded screw seal (Fig. 7A-38). Using a short piece of rubber tubing apply air pressure to the vacuum pipe by blowing into the tube and observe for leak bubbles. If bubbles appear, replace the m odulator. NOTICE: D o not use any method other than hum an lung power for applying air pressure, as pressures over 6 psi (41 kPa) may dam age the m odulator. Bellows Comparison Check Using a com parison gage, as shown in Figure 7A-39, com pare the load of a known good m odulator with the assembly in question. a. Install the m odulator that is kiow n to be acceptable on either end of the gage (Fig. 7A-40). b. Install the m odulator in question on the opposite end of the gage. (Fig. 7A-41). c. Holding the m odulators in a horizontal position, bring them together under pressure until either m odulator sleeve end just touches the line in the center of the gage (Fig. 7A-42). The gap between the opposite modulator sleeve end and the gage line should then be 1/16 in. (1.5 mm) or less. If the distance is greater than this amount, the m odulator in question should be replaced. Drive, N eutral, Park Li or L2 Reverse Drive, N eutral, Park LI or L2 Reverse 150 150 233 60 150 107 Fig. 7 A -3 6 ~ F lu id Pressure C h e c k - V eh icle Stationary, V a cu u m T ub e D iscon n e cted Fig. 7A-37--Fluid Pressure C h eck - V e iic le Stationary, V a c u u m T ub e Connected LIGHT T R U C K SE R V IC E M A N U A L 7A-36 A U TO M A TIC TRAN SM ISSIO N COMPARISON GAUGE 1 RYv \ i o r i j -j J u HOLD MODULATORS IN A HORIZONTAL POSITION, AS SHOWN, BRING THEM SLOWLY TOGETHER UNDER PRESSURE Fig. 7 A -38--V acu u m M o d u la to r Sleeve Alignment Check Roll the m ain body of the m odulator on a flat surface and observe the sleeve for concentricity to the can. If the sleeve is concentric and the plunger is free, the m odulator is acceptable. Once the m odulator assembly passes all of the above tests, it is an acceptable part and should be reused. 400 Trans. With Diesel Engine If erratic or poor quality shifting occurs due to incorrect vacuum supply to the m odulator, check the vacuum regulator valve and the vacuum pum p as described in Section 6A-6 of this m anual. MANUAL LINKAGE M anual linkage adjustm ent and the associated neutral safety switch are im portant from a safety standpoint. The neutral safety switch should be adjusted so th at the engine will start in the Park (P) and N eutral (N) positions only. W ith the selector lever in the P ark position, the parking pawl should freely engage and prevent the vehicle from rolling. The pointer on the indicator quadrant should line up properly with the range indicators in all ranges. Fig. 7 A -4 0 --H o ld in g M o d u la to rs in Horizontal Position TROUBLE DIAGNOSIS, BY CONDITION NOTICE: On vehicles with diesel engine, the vacuum source for the vacuum m odulator is the Vacuum R egulator Valve. W hen diagnosing shift com plaints on these vehicles, it is im portant to assure that the vacuum pum p is providing 22 in. (28 kPa) of vacuum to this valve. Also check the throttle linkage adjustm ent as outlined in Section 6A-3 of this manual. No Drive in Drive Range (Install pressure gage) • Low oil level - check for external leaks or defective vacuum m odulator (leaking diaphragm will evacuate oil from unit). • M anual linkage m aladjusted (correct alignment in m anual lever shift quadrant is essential); m anual valve disconnected from m anual lever pin. • Low oil pressure - refer to LOW L IN E PRESSU RE below. MODULATOR IN QUESTION KNOWN GOOD MODULATOR MODULATOR BELLOWS BAD Fig. 7A-39--Bellows Com parison Gage Fig. 7A-4 1--M odulator B ellow s - Bad LIGHT TR U C K SE R V IC E M A N U A L A U T O M A T IC TR A N SM IS S IO N 7A-37 e. Pressure boost bushing broken or defective. f. Pum p casting bad. (OUTER GAUGE LINES) MODULATOR BELLOWS GOOD Fig. 7 A -4 2 ~ M o d u la to r B e llo w s (Good) • F orw ard clutch: a. C lutch does not apply - piston cracked; seals missing, damaged; clutch plates burnt (Refer to B U R N E D C L U T C H PLATES). b. Pum p feed circuit-to-forw ard clutch oil seal rings missing or broken on pum p cover; leak or restriction in feed circuits; pump-to-case gasket mispositioned or damaged. Clutch drum ball check stuck or missing. • Roller Clutch - broken springs, dam aged cage or installed backwards. H ig h or Low O il Pressure (Refer to F L U ID PR E SSU R E CH EC K S) High Line Pressure • Vacuum Leak: a. Vacuum line disconnected. b. Leak on line from engine to m odulator. c. Im proper engine vacuum . d. Leak in vacuum -operated accessory (hoses, vacuum advance, etc.). • M odulator: a. Stuck m odulator valve. b. W ater in m odulator. c. Damaged, not operating properly. • D etent System: a. D etent switch actuated (plunger stuck) or shorted. b. D etent wiring shorted. c. D etent solenoid stuck open. d. D etent feed orifice in spacer plate blocked or restricted. e. D etent solenoid loose. f. D etent valve bore plug damaged. g. D etent regulator valve pin short. • Oil Pump: a. Pressure regulator a n d /o r boost valve stuck. b. Incorrect pressure regulator valve spring. c. Too many pressure regulator valve spacers. d. Pressure boost valve installed backwards or defective. Low Line Pressure • Low transm ission oil level. • Defective vacuum m odulator assembly. • Filter Assembly: a. Blocked or restricted. b. "O" Ring seal on intake pipe a n d /o r grom m et om itted or damaged. c. Split or leaking intake pipe. d. W rong filter assembly. • Oil Pump: a. Pressure regulator a n d /o r boost valve stuck. b. Pressure regulator valve spring too weak. c. N ot enough spacers in pressure regulator. d. G ear clearance, damaged, worn, drive gear installed backwards. e. Pum p-to-case gasket mispositioned. f. Defective or m ism atched pum p body/pum p cover. • Internal Circuit Leaks: a. Forw ard clutch leak (pressure low in D rive range pressure norm al in N eutral and Reverse). 1. Check pum p oil seal rings. 2. Check forw ard clutch seals. b. D irect clutch leak (pressure low in Reverse, pressure norm al in all other ranges). 1. Check center support oil seal rings. 2. Check direct clutch outer seal. 3. Check rear servo and front accum ulator pistons and rings for damage or missing. 6. Case Assembly: a. Porosity in intake bore area. b. Check case for interm ediate clutch cup plug leak or blown out. c. LI-reverse check ball mispositioned or missing (this will cause no reverse and no overrun braking in L I range). 1-2 Shift-Full Throttle Only • D etent switch sticking or defective (may stick in cold or wet weather). Can be detected by pulling connection at transm ission and obtaining norm al upshifts. • D etent solenoid: a. Loose. b. Gasket leaking. c. Sticks open. • C ontrol valve: a. Valve body gaskets - leaking, damaged, incorrectly installed. b. D etent valve train stuck. c. 3-2 valve stuck. • Case - porosity. First Speed Only, No 1-2 Shift • Governor: a. Valve sticking. b. D riven gear loose, damaged or worn (check for pin in case and length of pin showing); also check output shaft drive gear for nicks or rough finish if driven gear shows damage. LIGHT T R U C K SER V IC E M A N U A L 7A-38 A U T O M A T IC TRAN SM ISSIO N • C ontrol valve: a. 1-2 shift valve train stuck closed. b. G overnor feed channels blocked, leaking, pipes out of position, governor screen plugged. c. Valve body gaskets leaking, damaged, incorrectly installed. • Case: a. Interm ediate clutch cup plug leaking or blown out. b. Porosity between channels. c. G overnor feed channel blocked; governor bore scored or worn, allowing cross pressure leak. • Interm ediate clutch: a. Case center support - oil rings missing, broken, defective; orifice plug missing. b. C lutch piston seals missing, im properly assembled, cut. a. Servo piston seal ring dam aged or missing. b. Short band apply pin (this may also cause no overrun braking or slips in overrun braking - L I range). Refer to IN ST A L L A T IO N O F R E A R SERVO ASSEM BLY for pin selection procedure. c. Defective rear servo piston or bore. • Reverse or low band burnt, loose lining; apply pin or anchor pins not engaged; band broken. • D irect clutch: a. O uter seal damaged or missing. b. C lutch plates burnt (Refer to B U R N E D C LU TC H PLATES). • Forw ard clutch - clutch does not release (will also cause D rive in N eutral). • Center support - oil seal rings or grooves damaged or worn. First and Second Speeds Only, No 2-3 Shift Slips in all Ranges, Slips on Start • D etent solenoid - stuck open (detent shifts only - the 2-3 shift would occur at very high speeds, being interpreted as no 2-3 shift). • D etent switch. • Control valve: a. 2-3 valve train stuck. b. Valve body gaskets leaking, damaged, incorrectly installed. • D irect clutch: a. Center support oil rings missing, broken, defective. b. C lutch piston seals missing, im properly assembled, cut; piston ball check stuck or missing. (Install pressure gage) • Low fluid level. • Oil pressure - Refer to LOW L IN E PRESSURE. • Case - cross leaks, porosity. • Forw ard and direct clutches slipping (if burnt, Refer to B U R N E D C LU TC H PLA TE); oil seal rings on pum p cover broken or worn. Drive in Neutral • M anual linkage m aladjusted. • Internal Linkage: a. M anual valve disconnected or end broken. b. Inside detent lever pin broken. • Pum p Assembly - transm ission lube pressure leaking into forward clutch apply passage. • Forw ard Clutch: a. Burned plates - check cause. b. C lutch doesn’t release - will also cause no drive in Reverse. No Drive in Reverse or Slips in Reverse (Install pressure gage) • Low fluid level. • M anual linkage m aladjusted. • Oil pressure - refer to LOW L IN E PR E SSU R E above. • Control valve: a. Valve body gaskets leaking, damaged, incorrectly installed (O ther m alfunctions may also be indicated). b. Low reverse ball check missing from case (this will also cause no overrun braking in L I Range). c. 2-3 valve train stuck open (this will also cause 1-3 upshift in Drive range). d. Reverse feed passage restricted; also check case passages. • R ear servo and accum ulator: Slips 1-2 Shift (Install pressure gage) • Low fluid level. • Oil pressure - Refer to LOW L IN E PRESSU RE. • F ront accum ulator piston oil ring dam aged or missing. • C ontrol valve: a. 1-2 accum ulator valve train sticking. b. Porosity in valve body or case. c. Valve body attaching bolts not properly torqued. • R ear accum ulator oil ring missing or damaged; case bore damaged. • Pum p-to-case gasket mispositioned. • Case: a. Interm ediate clutch cup plug leaks excessively. b. Porosity between channels. c. Raised ridge around case center support bolt (does not allow control valve assembly to seat properly). • Interm ediate clutch: a. Piston seals missing or damaged; clutch plates burnt (Refer to B U R N E D C L U T C H PLATES). b. Center support - leak in feed circuit (oil rings damaged or grooves defective), excessive leak between tower and bushing, orifice bleed plug hole (0.020 dia.) blocked, center support bolt not seated properly in case. Rough 1-2 Shift (Install pressure gage) • Oil pressure - Refer to H IG H L IN E PRESSURE. • Control valve: a. 1-2 accum ulator valve train. b. Valve body-to-case bolts loose. c. W rong gaskets or off location, damaged. LIGHT T R U C K SE R V IC E M A N U A L A U T O M A T IC TR A N SM IS S IO N • Case: a. Interm ediate clutch ball missing or not sealing. b. Porosity between channels. • R ear servo accum ulator: a. Oil rings damaged. b. Piston stuck. c. Broken or missing spring. d. Bore damaged. • Interm ediate clutch - clutch plates burnt (Refer to B U R N E D C LU TC H PLATES. Slips 2-3 Shift (Install pressure gage) • Low fluid level. • Oil pressure - Refer to LOW L IN E PRESSU RE. • Control valve - accum ulator piston pin (leak at swedge end). • Case porosity. • D irect clutch: a. Piston seals leaking or ball check leaks. b. C enter support oil seal rings damaged; excessive leak between tower and bushing. Rough 2-3 Shift (Install pressure gage) • Oil Pressure - Refer to H IG H L IN E PRESSU RE. • F ro n t servo accum ulator: a. F ro n t accum ulator spring missing, broken. b. A ccum ulator piston stuck. • D irect clutch - air check for leak to outer area of clutch piston or center piston seal. • D am aged center support. No Engine Braking in L2 Range - 2nd Gear • F ro n t servo accum ulator: a. Servo or accum ulator oil rings or bores leaking. b. Servo piston cocked or stuck. • F ro n t band broken, burn t (check for cause), not engaged on anchor pin a n d /o r servo pin. No Engine Braking in L I Range - 1st Gear • Case assembly - LI-reverse check ball mispositioned or missing from case; case dam aged at LI-reverse check ball area. • R ear servo: a. Oil seal ring, bore or piston damaged; leaking apply pressure. b. R ear band apply pin short, im properly assembled. • R ear band broken, burn t (check for cause), not engaged on anchor pins or servo pin. Item s above will also cause slips in Reverse or no Reverse. No Part Throttle Downshift (Install pressure gage) • Oil pressure - Refer to H IG H O R LOW O IL PRESSU RE. • Control valve - 3-2 valve stuck spring missing or broken. 7A-39 No Detent Downshifts • D etent switch adjustm ents, connection (switch plunger activated approx. 7 /8 " at full throttle opening). • Solenoid inoperative, connections. • Control valve-detent valve train sticking. Low or High Shift Points (Install pressure gage) • Oil Pressure - Refer to H IG H O R LOW O IL PRESSURE. • Governor: a. Valve sticking. b. Feed holes restricted or leaking; pipes dam aged or mispositioned. c. Feed line screen plugged. • D etent switch. • D etent solenoid stuck open, loose, etc. (will cause late shifts). • C ontrol valve: a. D etent valve train. b. 3-2 valve train (detent upshifts possible). c. 1-2 shift valve train - 1-2 regulator valve stuck (this would cause a constant 1-2 shift point, regardless of throttle opening). d. Spacer plate gaskets mispositioned; spacer plate orifice holes missing or blocked. • Case porosity; interm ediate clutch cup plug leaking, missing. Won't Hold in Park • M anual linkage maladjusted. • Internal linkage: a. Parking brake lever and actuator defective (check for cham fer on actuator rod sleeve). b. Parking pawl broken. c. Parking pawl bracket loose, burned, rough edges or incorrectly installed. d. Parking pawl return spring missing, broken or incorrectly hooked. Transmission Noisy NOTICE: Before checking transm ission for w hat is believed to be "transm ission noise", make sure th at the noise is not from the water pump, alternator, power steering, etc. These components can be isolated by removing the proper belt and running the engine no more than two m inutes at one time. Park, Neutral and all Driving Ranges • Pum p Cavitation: a. Oil level low. b. Plugged or restricted filter. c. Intake pipe "O" ring damaged. d. Intake pipe split, porosity in case intake pipe bore. e. W ater in oil. f. Porosity or voids at transmission case (pum p face) intake port. g. Pum p-to-case gasket off location. • Pum p Assembly: LIGHT T R U C K SE R V IC E M A N U A L 7A-40 A U T O M A T IC TRAN SM ISSIO N a. G ears dam aged or defective; driving gear installed backwards. b. Crescent interference. c. Oil seal rings dam aged or worn. • Converter: a. Loose flexplate-to-converter bolts. b. Dam aged converter. F irs t, S ec o n d a n d /o r R e v e rs e G e a rs Planetary G ear Set: a. G ears or th ru st bearings damaged. b. F ront internal gear ring damaged. D u rin g A c c e le ra tio n - A n y G e a r • Transm ission or cooler lines grounded to underbody. • M otor m ounts loose or broken. S q u e a l a t L o w V e h ic le S p ee d Speedometer driven gear lubrication or replacement. shaft seal - requires Burned Clutch Plates • Forw ard clutch: a. Check ball in clutch drum damaged, stuck or missing. b. C lutch piston cracked, seals dam aged or missing. c. Low line pressure (Refer to LOW L IN E PRESSU RE). d. M anual valve mispositioned (may also cause front band failure). e. R estricted oil feed to forward clutch (clutch housing to inner and outer areas not drilled, restricted, porosity in pump, etc.). f. Transm ission case valve body face not flat or porosity between channels. g. M anual valve bent and center land not ground properly. h. Pum p cover oil seal rings missing, broken or undersize, ring groove oversize. • Interm ediate Clutch: a. C onstant bleed orifice in center support missing. b. R ear accum ulator piston oil ring damaged or missing. c. 1-2 accum ulator valve stuck in control valve assembly. d. Interm ediate clutch piston seals damaged or missing. e. Center support bolt loose. f. Low line pressure (Refer to LOW L IN E PRESSURE). g. Interm ediate clutch cup plug in case missing. h. Transm ission case valve body face not flat or porosity between channels. i. M anual valve bent and center land not ground properly. • D irect Clutch: a. R estricted orifice in vacuum line to m odulator (poor vacuum response). b. Check ball in clutch piston damaged, stuck or missing. c. Defective m odulator bellows. d. C enter support bolt loose (bolt may be tight in support but not holding support tight to the case). e. Center support oil rings or grooves damaged or missing. f. C lutch piston cracked, seals damaged or missing. g. F ront and rear servo pistons a n d /o r seals damaged. h. 3-2 valve, 3-2 valve spring or 3-2 spacer pin installed in wrong location in 3-2 valve train bore. i. M anual valve bent and center land not ground properly. j. Transm ission case valve body not flat or porosity between channels. k. Interm ediate roller clutch installed backwards. • In addition, burned clutch plates can be caused by incorrect usage of clutch plates. Also, anti-freeze in transmission fluid can cause severe damaged, such as large pieces of clutch plate material peeling off. LIGHT T R U C K SE R V IC E M A N U A L A U T O M A T IC TRAN SM IS S IO N 7A-41 FORWARD CLUTCH DIRECT CLUTCH FRONT BAND INTERMEDIATE CLUTCH INTERMEDIATE ROLLER CLUTCH LOW ROLLER CLUTCH REAR BAND NEUTRAL O FF O FF OFF O FF In e ffe c tiv e In e ffe c tiv e O FF D R IV E , First G e a r ON O FF O FF O FF In e ffe c tiv e E ffe ctive O FF D R IV E , S e cond G e a r ON O FF OFF ON E ffe c tiv e In e ffe c tiv e O FF D R IV E , T h ird G e a r ON ON OFF ON In e ffe c tiv e In e ffe c tiv e O FF Li ON O FF O FF O FF In e ffe c tiv e E ffe c tiv e ON L2 ON O FF ON ON E ffe c tiv e In e ffe c tiv e O FF REVERSE O FF ON O FF O FF In e ffe c tiv e In e ffe c tiv e ON Fig. 7 A -4 3 --4 0 0 C lutch A p p ly C hart LIGHT T R U C K SE R V IC E M A N U A L 7A-42 I 1 I 1 [Z ^ l CZZI 1 1 Fig. 7A-44--400 AUTOMATIC TRANSMISSION M A IN L IN E PRESSURE INTAKE PRESSURE CONVERTER PRESSURE G O VE R N O R PRESSURE M O D U LA TO R PRESSURE DETENT PRESSURE 1 -2 A C C UM ULA TO R PRESSURE Hydraulic Circuit A U T O M A T IC TR A N SM IS S IO N 7A-43 ON V EH IC LE S E R V IC E TRANSMISSION REPLACEMENT If necessary, the catalytic converter may have to be disconnected to provide adequate clearance for transm ission removal. This procedure will include removal of the converter support bracket. Removal Before raising the truck, disconnect the battery and release the parking brake. 1. Raise truck on hoist. 11. Remove transm ission to engine m ounting bolts and remove oil filler tube at transmission. 12. Raise transm ission to its norm al position, support engine with jack and slide transmission rearw ard from engine and lower it away from vehicle. 13. Use converter holding Tool J-5384 when lowering transmission or keep rear of transm ission lower than front so as not to lose converter. Installation 2. Remove propeller shaft. 3. D isconnect speedom eter cable, electrical lead to case connector, vacuum line at m odulator, and oil cooler pipes. 4. Disconnect shift control linkage. 5. Support transm ission with suitable transm ission jack. 6. Disconnect rear m ount from fram e crossmember. 7. Remove two bolts at each end of the frame crossm em ber and remove crossmember. 8. Remove converter under pan. The installation of the transm ission is the reverse of the removal with the following additional steps. 1. Before installing the flexplate to converter bolts, m ake certain that the weld nuts on the converter are flush with the flexplate and the converter rotates freely by hand in this position. Refer to Fig. 7A-45 for instructions on attaching the converter to-flexplate. This will insure proper converter alignment. 2. Install transm ission support crossm em ber to transm ission and frame with taper on support sloping tow ard rear. 9. Remove converter-to-flexplate bolts. Refer to Fig. 3. A fter installation of transmission, check linkage for 7A-45. proper adjustm ent. 10. Loosen exhaust pipe to m anifold bolts 4. Remove truck from hoist. approxim ately 1/4 in. (6.35 m m), and lower transm ission until jack is barely supporting it. 1. M O V E C O N VER TER F O R W A R D T O C O N T A C T A T T A C H IN G SURFACE O N FLEX­ PLATE PRIOR TO T IG H T E N IN G BOLTS. 2. A L IG N SLOT IN FLEXPLATE TH A T H A S A N ID E N T IF IC A T IO N HO LE N E A R IT, W IT H A N A T T A C H M E N T HOLE IN C O N V E R T E R . INSTALL BOLT A N D N U T A N D T IG H T E N TO SPEC IFIED T O R Q U E . T IG H T E N ALL R E M A IN IN G BOLTS TO SP EC IFIE D T O R Q U E AS TH EY ARE INSTALLED. Fig. 7A-45--Typical Transm ission M ounting, Net-Hole Design LIGHT T R U C K SER V IC E M A N U A L 7A-44 A U T O M A T IC TRAN SM ISSIO N Fig. 7 A -46 --R e m ovin g G overnor A ttac h in g S c re w s REAR EXTENSION OIL SEAL Removal 1. Remove propeller shaft. 2. Pry seal out with screw driver. Installation Fig. 7 A -4 7 -R e m o v in g V a cu u m M o d u la to r and Valve 3. Remove m anual shaft retaining pin from case. 1. F or all models except CL, use Tool J-21359 to drive seal in place. F o r CL models, use J-24057. 2. Reinstall propeller shaft. 4. Remove m anual shaft and jam nut from case, as shown in Fig. 7A-48. GOVERNOR Do not remove m anual shaft seal unless replacement is required. Removal 1. Remove governor cover attaching screws, cover, and gasket, as shown in Fig. 7A-46. 2. D iscard gasket. 3. W ithdraw governor assembly from case. In s ta lla tio n 5. Remove parking actuator rod and detent lever assembly. 6. Remove parking pawl bracket attaching screws and bracket. 7. Remove parking pawl return spring. Installation of the governor assembly is the reverse of the removal. Use a new gasket under the governor cover. Adjust fluid level. MODULATOR AND MODULATOR VALVE Removal 1. Remove m odulator assembly attaching screw and retainer. 2. Remove m odulator assembly from case. D iscard "O" ring seal. 3. Remove m odulator valve from case. Refer to Fig. 7A-47. Installation Installation of the m odulator assembly and m odulator valve is the reverse of the removal. Use a new "O" ring seal on the m odulator assembly. Adjust fluid level. PARKING LINKAGE-10, 20 SERIES Removal 1. Remove bottom pan and oil filter. 2. U nthread jam nut holding detent lever to m anual shaft. Fig. 7A -48-R em oving Jam Nut from M anual Shaft A U T O M A T IC TRAN SM IS S IO N 7A-45 C O N T R O L VALVE A SS Y . GOVERNOR PIPES G O V E R N O R SCREEN A SSY. G O V E R N O R FEED PIPE H O L E Fig. 7 A -5 0 ~ G o v e rn o r Screen Position Fig. 7 A -4 9 ~ R e m o v in g Control V alve and G overnor Pipes The following steps should be com pleted unless part replacem ent is required. 8. Remove parking pawl shaft retainer. 9. Remove parking pawl shaft, cup plug parking pawl shaft, and parking pawl. In s ta lla tio n Installation of the parking linkage is the reverse of the removal. Use new seal and cup plug, if removed, and new bottom pan gasket. CONTROL VALVE BODY PRESSURE REGULATOR VALVE Rem oval 1. Remove bottom pan and filter. 2. Compress regulator boost valve bushing against pressure regulator spring and remove snap ring, using J5403 pliers. 3. Remove regulator boost valve bushing and valve. 4. Remove pressure regulator spring. 5. Remove spring retainer, washer spacer(s) if present, and regulator valve. In s ta lla tio n Rem oval 1. Remove bottom pan and filter. 2. Disconnect lead wire from pressure switch assembly. 3. Remove control valve body attaching screws and detent roller spring assembly. Do not remove solenoid attaching screws. A solid type pressure regulator valve m ust only be used in a pum p cover with a squared-off pressure regulator boss (Refer to Figure 7A-51). A pressure regulator valve with oil holes and orifice cup plug may be used to service either type pump. Installation of the pressure regulator valve is the reverse of the removal. Install new gasket on oil pan and adjust fluid level. NOTICE: If the transm ission is in the vehicle, the front servo parts may drop out as the control valve assembly is removed. 4. Remove control valve body assembly and governor pipes. If care is taken in removing control valve body the six (6) check balls will stay in place above the spacer plate. Refer to Fig. 7A-49. 5. Remove the governor screen assembly from end of governor feed pipe or from the governor feed pipe hole in the case (Fig. 7A-50). Clean governor screen in clean solvent and air dry. NOTICE: PUMP COVER Do not drop m anual valve. 6. Remove the governor pipes and m anual valve from control valve body. In s ta lla tio n Installation of control valve body is in reverse of removal. See Overhaul M anual. A djust fluid level. FOR ID E N T IF IC A TIO N SQUARED OFF PRESSURE REG. BOSS. Fig. 7A-5 1--Pressure Regulator Valve LIGHT T R U C K SER VIC E M A N U A L 7A-46 A U T O M A T IC TRAN SM IS S IO N meeting G M specification 123M or its equivalent. U nder no condition use copper or alum inum tubing to replace steel tubing. Those m aterials do not have satisfactory fatique durability to w ithstand norm al vehicle vibrations. Steel tubing should be flared using the upset (double lap) flare m ethod which is detailed in Section 5. OTHER SERVICE OPERATIONS The following operations when done as single operations and not as part of a general overhaul should, as a practical m atter, be perform ed with the transmission in the vehicle. Refer to the "Transm ission Disassembly and Reassembly" section of the O verhaul M anual for service procedures. 1. Oil filler pipe. 2. Oil pan and gasket. Fig. 7 A -5 2 ~ T ra n sm issio n Su p p o rt Strut Rod SUPPORT STRUT ROD Replacement The transm ission strut rod attachm ent is shown in Fig. 7A-52. Remove the two bolts when replacing the strut rod. W hen removing the transm ission, it is only necessary to remove the bolt at the transm ission end o f the strut rod. 3. Down shift solenoid or connector. 4. Valve body spacer plate, gasket and check balls. 5. F ront accum ulator piston. 6. R ear servo and rear accum ulator assembly. 7. R ear band apply checking with Tool J-21370. 8. Front servo assembly. 9. Speedo driven gear. OIL COOLER PIPES 10. Case extension or gasket. If replacem ent of transm ission steel tubing cooler pipes is required, use only double w rapped and brazed steel tubing 11. Filter and "O" ring. 12. Pressure switch assembly. LIGHT TR U C K SE R V IC E M A N U A L A U T O M A T IC TR A N SM IS S IO N 7A-47 SPECIFICATIONS 350 C (MV4) P u m p C o v e r to P u m p B o d y .............................................. P u m p A sse m b ly to C a s e .................................................. V alv e Body and A u x ilia ry V alve Body P a rk in g L o c k B r a c k e t „. .................................................. ____23 . . . . 24 . . . . 14 ____39 ..........4 . . . . 14 . . . . 33 . . . . 14 ....3 3 ..........6 . . . . 47 ___ 12 ....4 7 O il P a n to C a s e ..................................................................... E x te n sio n to C a s e ............ ................................................. M o d u la to r R e ta in e r to C a s e ........................................... In n e r S e le c to r L e v e r to S h a ft............ ............................ D e te n t V alv e A ctu atin g B r a c k e t .................................... C o n v e r te r to F ly w h e e l B o lts ......................................... U n d er P a n to T r a n s m is s io n C a s e ............................... T r a n s m i s s i o n C a s e to E n g in e ......................................... O il C o o le r P ip e C o n n e c to rs to T r a n s m is s io n C a s e o r R a d i a t o r ............................................................ ____14 O il C o o le r P ip e to C o n n e c to r s ...................................... ..........13 D e te n t C ab le to T r a n s m i s s i o n ................... .................. ..........8 D e te n t C a b le to C a r b ......................................................... . . . . 12 S o len o id A s s e m b l y .............................................................. ..........4 G o v e rn o r P r e s s u r e S w itc h .............................................. . . . . 10 N- m . N- m . N- m . N- m . N- m . N- m . N- m . N* m . N- m . N- m . N- m . N- m . N- m . . . .1 7 .1 8 .5 ..1 3 0 . . .2 9 ...4 0 ..1 3 0 ...2 5 ...3 0 ...2 5 ...5 2 ...3 5 . .1 1 0 ...3 5 f t. f t. in . f t. in . in . ft. in . ft. in . f t. in . ft. lb . lb . lb . lb . lb . lb . lb . lb . lb . lb . lb . lb . lb . N- m . N- m . N* m . N- m . N* N- ..1 2 5 ...1 0 ...7 5 ..1 1 2 ____3 ___ 8 in . f t. in . in . f t. ft. lb . lb . lb . lb . lb . lb . 400 (AMO) ........ 24 N- m . . . . 1 8 f t. lb . ..........24 N- m . . . .1 8 ft. lb . ____29 P u m p to C a s e A tta c h in g B o l t s ...................................... ..........24 E x te n s io n H o u sin g to C a s e A ttac h in g B o lts ............ ..........24 ............ 9 C o n tro l V a lv e Body B o l t s ................................................ ..........10 B o tto m P a n A tta c h in g S c r e w s ....................................... ..........14 ..........24 ..........24 M an u al L e v e r to M an u al S haft N u t ............................. ..........10 M an u al S h aft to In s id e D e te n t L e v e r ........................... ..........24 L in k a g e S w iv el C la m p N u t .............................................. ..........57 C o n v e r te r D u s t S h ield S c r e w s ...................................... ___ 124 T r a n s m i s s i o n to E n g in e M ounting B o l t s ................. ..........47 C o n v e r te r to F ly w h e e l B o l t s ......................................... ..........47 R e a r M ount to T r a n s m i s s io n B o l t s ............................. ..........54 R e a r M ount to C r o s s m e m b e r B o lt . ........................... ..........54 C r o s s m e m b e r M o u n tin g B o l t s ....................................... ..........32 O il C o o le r L i n e ..................................................................... ..........13 L in e P r e s s u r e T a k e -O ff P l u g ....................................... ..........17 S t r a i n e r R e ta in e r B o l t ..................................................... ..........13 O il C o o le r P ip e C o n n e c to rs to T r a n s m is s io n C a s e o r R a d ia to r .............................................................. .......... 14 O il C o o le r P ip e to C o n n e c to r ......................................... .......... 1 D o w n sh ift S w itch to B r a c k e t........................................... ............ 2 N- m . . . . 2 3 N* m . . . .1 8 . . .23 N- m . . . . 1 8 ____7 N. ____8 NN- m . . . . 1 2 N* m . . . . 1 8 N- m . . . . 1 8 8 NN- m . . . . 1 8 N- m . . . .4 3 N* m . . . . 9 3 N- m . . . . 3 5 N* m . . . .3 5 N- m . . . . 4 0 N- m . . . . 4 0 N- m . . . . 2 5 N* m . . . . 1 0 N* m . . . . 1 3 N- m . . . . 1 0 f t. f t. f t. f t. ft. f t. f t. f t. ft. ft. ft. ft. ft. ft. ft. ft. ft. ft. ft. ft. ft. lb . lb . lb . lb . lb . lb . lb . lb . lb . lb . lb . lb . lb . lb . lb . lb . lb . lb . lb . lb . lb . N* m . ..1 2 5 in. lb . N* m . . . . 1 0 in . lb . N- m . . . . 2 2 in . lb . LIGHT TR U C K SE R V IC E M A N U A L 7A-48 A U T O M A T IC TRAN SM IS S IO N S P E C IA L T O O LS 1. J-8763-02 2. J-3289-20 3. 4. 5. J-8092 J-21465-13 J-23062-3 6. 7. J-23062-7 J-21465-15 8. 9. 10. 11. J-23329 J-9534-01 J-23327 J-23062-2 12. 13. J-23062-1 J-21424-9 Transmission Holding Fixture (Used with J-3289-20 Base) Transmission Holding Fixture Base Driver Handle (Threaded type) Driver Handle Extension (Used with J-8092) Sun Gear and Reaction Carrier Bushing Output Shaft Bushing Installer Stator Shaft Front Bushing Remover (Used with J-8092) Direct Clutch Bushing Installer Output Shaft Bushing Remover Clutch Spring Compressor Stator Shaft Rear Bushing Installer (Both Rear) Case Bushing Remover and Installer Extension Housing Bushing Remover and Installer (Used with J-8092) 14. J-21424-7 15. J-23062-5 16. 17. 18. J-5154 or J-21426 J-21359 J-7004 19. J-21885 20. J-23069 * 21. J-2619-01 Stator Shaft Front Bushing Installer (Used with J-8092) Input Ring Gear Bushing Remover and Installer Extension Housing Oil Seal Installer Pump Oil Seal Installer Slide Hammers (Pair) (Ear Pump Body removal) (3 /8 " x 16 tread) 2-3 Accum ulator Piston Compressor Intermediate Accum ulator Cover Remover and Installer Slide Hammer (5 /8 " x 18 with 1/2" x 13 Adapter) Not Illustrated J-21369 J-8001 Converter Pressure Check Fixture Dial Indicator Set (.001" Increments, .001" Travel) Fig. 7A-1 S T -3 5 0 Special Tools LIGHT T R U C K SE R V IC E M A N U A L A U T O M A T IC TRAN SM IS S IO N 1 . J-61 16-01 2 . J -8 0 9 2 3. 4. J -2 1 3 5 9 J -2 1 3 6 4 5. J -2 6 1 9 6. 7. 8. J -5 1 5 4 J -6 5 8 5 J -9 5 3 9 9. J -5 5 9 0 10. J -2 1 8 6 7 11. J - 2 1370-6 12. J - 2 1370-5 13. J - 2 1795-1 Rear Unit H o ld in g Fixture Driver H an dle Pum p Oil S e a l Installer H o ld in g Fixture A dapter (U sed with J-61 16-01 Fixture) S lid e H am m er (U sed with 2 6 1 9 -4 A d a p ter and R em over T o o ls J - 2 1 465-01) Extension Oil S e a l Installer S lid e H am m er W e ig h ts S lid e H am m er B o lts ( 3 / 8 " - 16 T hreads) S p e e d o G ear Installer Pressure G a u g e and H ose Rear B a n d A p p ly Fixture Rear B a n d A p p ly Pin G ear Unit A sse m b ly H o ld in g 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. J - 2 1 7 95-2 J -5 3 8 4 J - 2 1465-01 J - 2 1465-5 J - 2 1465-3 J -2 1 4 6 5 -2 J - 2 1465-1 J -2 1 4 6 5 -1 7 J - 2 1465-8 J -2 1 4 6 5 -1 3 J - 2 146 5 -6 J -2 1 4 6 5 -1 5 J - 2 1 4 6 5 -1 6 J - 2 1465-9 J -2 1 4 6 5 -1 0 J -2 2 1 8 2 7A-49 Part of A b o v e H o ld in g Tool Converter H o ld in g Strap B u sh in g Tool Set Part.of B u sh in g Tool Set Part of B u sh in g Tool Set Part of B u sh in g Tool Set Part of B u sh in g Tool Set Part of B u sh in g Tool Set Part of B u sh in g Tool Set Part of B u sh in g Tool Set Part of B u sh in g Tool Set Part of B u sh in g Tool Set Part of B u sh in g Tool Set Part of B u sh in g Tool Set Part of B u sh in g Tool Set Ext. B u sh in g Rem. and Inst. (Not Illustrated) Fig. 7 A -2 S T -4 0 0 Special Tools LIGHT T R U C K SE R VIC E M A N U A L 7A-50 A U T O M A T IC TRAN SM ISSIO N 1. J-8763 2 . J-3289-14 3. 4. J-21427-1 J-9539 5. J-8105 6 . J-22269-01 7. J-21369 8 . J-21362 9. J-21363 10. J-21409 Transm ission H old in g Fixture H o ld in g Fixture Base Speedo Gear Rem over Sid e H am m er B o lts (3 /8 " - 16 Threads) Speedo Gear Rem over Puller A cc u m u la to r Piston Rem over and Installer Converter Pressure Check Fixture Seal Protector - Forw ard and Direct Clu tch - Inner Seal Protector - Interm ediate C lu tch - Inner Seal Protector - Forw ard Clu tch - Outer 11. J-21664 12. 13. 14. 15. 16. Not J-4670 J-8059 J-5586 J-5403 J 1313 Illustrated J-24684 J-24675 C lu tch S p rin g C om pressor A dapter R in g C lu tch S p rin g C om pressor Sn a p R in g Pliers S n a p R in g Pliers Sn a p R in g Pliers T orqu e W rench 0-140 Ft. Lbs. Pressure Regulator Valve C om pressor A c c u m u la to r Piston A dapter (Used w ith J-22269-01) Fig. 7A-3ST--400 Special Tools LIGHT T R U C K SE R V IC E M A N U A L MANUAL TRANSMISSIONS 7B-1 SECTION 7B MANUAL TRANSMISSION CONTENTS G eneral D escription............................................................ 7B-1 76mm (3 S p e e d )............................................................. 7B-1 77mm (3 S p e e d )............................................................. 7B-1 89mm (4 S p e e d ).............................................................7B-1 117mm (4 S p e e d )........................................................... 7B-2 M aintenance and A d ju stm e n ts....................................... 7B-9 D iagnosis............................................................................... 7B-11 Free Pedal T ra v e l...........................................................7B-11 Spin Down T im e .............................................................7B-11 Shift L in k ag e.................................................................. 7B -11 Shift E ffort....................................................................... ..7B-12 On Vehicle Service R ep lacem en t......................................................................7B-15 A lig n m e n t.......................................................................... 7B-17 Oil S e a l........................................................ .................... ..7B-18 Speedo G e a r.......................................................................7B-18 Side C over........................................................................ ..7B-19 Shift Control Lever........................................................ ..7B-19 S pecifications....................................................................... ..7B-20 Special T ools........................................................................ ..7B-21 GENERAL DESCRIPTION THREE-SPEED TRANSMISSIONS 3-Speed 76mm 3-Speed 77mm M anual transmissions are designated according to: (A) the num ber of forward gears, and (B) the m easured distance between centerlines of the m ainshaft and the countergear. The three speed synchrom esh transm issions (Figs. 7B-1 through 7B-3) are representative of a constant-m esh tran s­ mission design. Fundam ental components of these units are the case, which houses the gears and shaft; the shift control mechanism and the various shafts and gears. The input shaft has an integral main drive gear and rotates with the clutch driven plate; th at is, the shaft rotates all the tim e the clutch is engaged and the engine is running. The input shaft is supported in the case by a ball bearing and at the front end by an oil im pregnated bushing m ounted in the engine crankshaft. The drive gear is in constant mesh with the countershaft drive gear. Since all gears in the countershaft cluster are integral to the shaft, they also rotate at the time the clutch is engaged. The countergear is carried on roller bearings at both ends and thrust is absorbed by thrust washers located between the countergear and thrust bosses in the case. The transm ission m ainshaft is held in line with the input shaft by a pilot bearing at its front end, which allows it to rotate or come to rest independently of the input shaft. In the 76mm unit, the m ainshaft is carried at the rear by a ball bearing m ounted in the front face of the extension housing. In the 77mm unit, the m ainshaft is carried at the rear by a ball bearing m ounted in the rear face of the case. Helical gears are incorporated throughout, except for reverse gear in the 77 mm transm ission. The m ainshaft gears are free to rotate independently on the m ainshaft and are in co n stan t mesh w ith the c o u n te rsh a ft gears. The reverse idler gear is carried on a bushing, finish bored in place, and thrust is taken on the thru st bosses of the case. The transm issions are fully synchronized in all forward speeds; how ever, reverse gear is not. T he synchronizer assemblies consist of a hub, sleeve, two key springs and three synchronizer keys. The synchronizer hubs are splined to the m ainshaft and retained by snap rings. These assemblies perm it gears to be selected w ithout clashing,by synchroniz­ ing the speeds of m ating parts before they engage. In the 76mm unit, the driven gear, second speed gear, first speed gear and reverse gear are rigidly connected to the countergear. In the 77mm transm ission, only the driven gear, second speed gear and first speed gear are rigidly connected to the countergear. The engine driven clutch gear drives the countergear through a constant mesh counter­ shaft driven gear. The countergear rotates in a direction opposite, or counter, to the rotation of the clutch gear. Forward speed gears on the countergear rem ain in constant mesh with two nonsliding m ainshaft gears giving first and second speed. T hird speed is a direct drive with the clutch gear engaged directly to the m ainshaft. Forward gears are engaged through two sliding synchronizer sleeves m ounted on the m ainshaft. E ngagem ent of the co n stant mesh m ainshaft gears to the m ainshaft is accomplished through blocker ring-type synchronizers. FOUR-SPEED TRANSMISSION 4-Speed 89mm The four speed transm ission with overdrive has an 89mm center distance and is designed to combine normal perform ance in the city with improved fuel economy on the highway. G ear ratios are: first 3.09 to 1; second 1.67 to 1; third 1.00 to 1; fourth (overdrive) 0.73 to 1. All forward gears are fully synchronized. The synchronizer assemblies consist of a hub, sleeve, two key springs and three synchro­ nizer keys. T he synchronizer hubs are splined to the m ainshaft and retained by snap rings. These assemblies perm it gears to be selected w ithout clashing, by synchroniz­ ing the speeds of m ating parts before they engage. The drive pinion (input shaft) is supported by a ball bearing in the transm ission case and an oil im pregnated bushing pressed in the end of the crankshaft. The m ainshaft front end is supported by roller bearings in the end of the main drive pinion and a ball bearing in the front of the extension housing. T he o u tput end of the LIGHT T R U C K SE R V IC E M A N U A L 7B-2 MANUAL TRANSMISSIONS m ainshaft is splined to the sliding universal joint yoke, which is supported by a bushing in the extension housing. The countershaft gear is supported by a double row of needle type roller bearings at each end and the thrust is taken on thrust washers between the ends of the gear and the transmission case. The alignm ent of the needle type roller bearings within the gear is m aintained by a tubular spacer in the center and four thrust washers (one being used between the rows of roller bearings and one at each end). The countershaft is not a press fit in the case bores, but has .005 inch diam eter clearance. An expansion plug is pressed into a counter bore at the front of the case to prevent oil leakage around the countershaft. The reverse idler gear is supported on a bronze bushing, pressed into the gear. A m agnetic disc is attached to bottom, near rear of case under countershaft gear. This m agnet collects and prevents circulation of chips in transm ission oil. 4-Speed 117mm The 117mm, Model C H 465 truck transm ission (Fig. 7B-4 and 7B-5) uses a constant mesh first gear th at engages LIGHT T R U C K S E R V IC E M A N U A L with the second speed synchronizer sleeve. Second, third and fourth gears are synchronized. The clutch gear is supported by a heavy duty ball bearing. T he forward end of the m ainshaft is supported by a loose collar-type bearing inside the clutch gear, while the rear is carried on a ball bearing in the case. End play is taken up by the rear flange retaining nut. The countergear is supported at the rear by a single row ball bearing which takes the thrust load, and by a roller bearing at the front. Incorporated in the cover is a ball pin type interlock which prevents sim ultaneous engagem ent of two gears. As one rod is moved, it pushes a ball out that engages the other two rods to prevent their movement. G earshift levers on m anual transm issions are located either on the steering column or on the floorboard. R egard­ less of location, the lever perform s two operations: It selects the gear assembly to be moved, and moves it either forward or backw ard into the desired gear position. The transmission action is the same w hether a floor-type shift lever or a steering column shift lever is used. W hen the shift lever is moved, the m ovem ent is carried by linkage to the transmission. MANUAL TRANSMISSIONS 1 2 30 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 3 31 4 5 32 Clutch Gear Bearing Retainer Pilot Bearings Case 3rd Speed Blocker Ring 2-3 Synch. Snap Ring 2-3 Synch. Hub 2nd Speed Blocker Ring 2nd Speed Gear 1st Speed Gear 1st Speed Blocker Ring 1st Speed Synch. Hub 1st Speed Synch. Snap Ring Reverse Gear 6 7 33 8 34 9 35 10 36 11 12 13 37 38 14 39 15 16 17 18 19 20 7B-3 21 40 15. Reverse Gear Thrust and Spring Washers 16. Snap R ing— Bearing to Mainshaft 17. Extension 18. Vent 19. Speedometer Drive Gear and Clip 20. Mainshaft 21. Rear Oil Seal 22. Retainer Oil Seal 23. Snap R in g— Bearing to Gear 24. Clutch Gear Bearing 25. Snap R ing— Bearing to Case 26. Thrust Washer— Front 27. Thrust Washer— Rear 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. Snap R in g— Bearing to Extension Rear Bearing Countegear Roller Bearings Anti-Lash Plate Assembly Magnet 2-3 Synch. Sleeve Countergear Counter Shaft Reverse Idler Shaft 1st Speed Synch. Sleeve " E ” Ring Reverse Idler Gear W oodruff Key Fig. 7B-1--3-Speed 76m m , Cross-Section LIGH T T R U C K SE R V IC E M A N U A L 7B-4 MANUAL TRANSMISSIONS Thrust W asher - Front Bearing W asher Needle Bearings Countergear Needle Bearings Bearing W ahser Thrust W asher - Rear Counter Shaft W o o d ru ff Key Bearing Retainer Gasket Oil Seal Snap Ring - Bearing to Case 14. Snap Ring - Bearing to Gear 15. Drive Gear Bearing 16 Case 17. Drive Gear 18 Pilot Bearings 1. 2 3. 4. 5. 6 7 8 9 10 11. 12. 13 19. 3rd Speed Blocker Ring 20 "E " Ring 21. Reverse Idler Gear 22 Reverse Idler Shaft 23. W oodruff Key 24. Snap Ring - Hub to Shaft 2-3 Synchronizer 25 Sleeve 26 Synchronizer Key Spring 27. 2-3 Synchronizer Hub Assembly 2nd Speed Blocker 28 Ring 29 2nd Speed Gear 30. Mainshaft 31. 1st Speed Gear 1st Speed Blocker 32 Ring 33. 34. 35 36 37. 38 39 40. 41. 42. 43 44. 45. 46. 1-2 Synchronizer Hub Assembly 1-2 Synchronizer Sleeve Snap Ring - Hub to Shaft Reverse Gear Thrust Washer Spring Washer Rear Bearing Snap Ring - Bearing to Shaft Speedometer Drive Gear Retaining Clip Gasket Snap Ring - Rear Bearing to Extension Extension Oil Seal Fig. 7B-2~3-Speed 76m m , Exploded View LIGHT T R U C K S E R V IC E M A N U A L 47. 48. 49 Gasket 2-3 S hift Fork 1st and Reverse Shift Fork 50. 2-3 S hifter Shaft Assembly 51 1st and Reverse Shifter Shaft Assembly 52 ” 0 " Ring Seal 53 "E " Ring 54 Spring 2nd and 3rd Detent 55 Cam 56 1st and Reverse Detent Cam 57. Side Cover 58 TCS Switch and Gasket 59 Lip Seal MANUAL TRANSMISSIONS 1. 2. 3. 4. MAINSHAFT ROLLER BEARINGS 2ND & 3RD SYNCHRONIZER RETAINING RING SYNCHRONIZER BLOCKER RINGS 2ND & 3RD SYNCHRONIZER SPRING 35. 36. 37. 38. 7B-5 EXTENSION HOUSING TO CASE GASKET SPEEDOMETER DRIVER GEAR RETAINING CLIP TRANSMISSION REAR BEARING LOCK RING MAINSHAFT BEARING ASSEMBLY 5. 2 N D & 3 R D S Y N C H R O N IZ E R S L E E V E 3 9 . S P E E D O M E T E R D R IV E G E A R 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 2ND & 3RD SYNCHRONIZER KEYS 2ND & 3RD SYNCHRONIZER HUB SECOND SPEED GEAR 1ST SPEED GEAR RETAINING RING 1ST SPEED GEAR TABBED WASHER 1ST SPEED GEAR REVERSE SYNCHRONIZER SPRING 1ST 8c REVERSE SYNCHRONIZER SLEEVE 8t GEAR REVERSE SYNCHRONIZER KEYS 1ST & REVERSE SYNCHRONIZER HUB 1ST 8i REVERSE SYNCHRONIZER RETAINING RING REAR BEARING RETAINING RING TRANSMISSION MAINSHAFT REVERSE-SYNCHRONIZER ASSEMBLY ACCESS COVER BOLTS ACCESS COVER ACCESS COVER GASKET BEARING RETAINER - TO CASE BOLTS BEARING RETAINER - CLUTCH GEAR GASKET - CLUTCH GEAR BEARING RETAINER SEAL ASSEMBLY - CLUTCH GEAR BEARING RETAINER CLUTCH GEAR BEARING RETAINING RING CLUTCH GEAR BEARING LOCK RING CLUTCH GEAR BEARING ASSEMBLY CLUTCH GEAR EXPANSION PLUG FILLER PLUG TRANSMISSION CASE MAGNET CASE 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 53. 54. 55. 56. 57. 58. 59. 60. 61. 62. 63. 64. 65. 66. 67. EXTENSION TO CASE WASHER EXTENSION TO CASE BOLT TRANSMISSION EXTENSION VENTILATOR ASSEMBLY EXTENSION HOUSING ASSEMBLY EXTENSION HOUSING BUSHING EXTENSION HOUSING OIL SEAL ASSEMBLY COUNTERGEAR THRUST WASHER COUNTERGEAR SPACER COUNTERGEAR ROLLER BEARINGS COUNTERGEAR SHAFT COUNTERGEAR SPRING PIN COUNTERGEAR 2ND 8> 3RD SHIFTER FORK SHIFT FORK LOCKING SCREW 1ST 8. 2ND SHIFTER INTERLOCK SPRING SHIFTER INTERLOCK PIN 1ST 8t REVERSE SHIFT RAIL 1ST 8. REVERSE SHIFT FORK 2ND 8i 3RD SHIFTER INTERLOCK SPRING 2ND 8t 3RD SHIFT RAIL REVERSE IDLER GEAR THRUST WASHER REVERSE IDLER GEAR SHAFT SPRING PIN IDLER GEAR SHAFT REVERSE IDLER GEAR BUSHING REVERSE IDLER GEAR REVERSE IDLER GEAR ASSEMBLY SEAL TRANSMISSION SHIFTER TRANSMISSION SHIFTER SHAFT & LEVER ASSEMBLY Fig. 7B-3--3-Speed 77m m , Exploded View LIG H T T R U C K S E R V IC E M ANU AL 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 1 1. D riv e G e a r B earin g Retainer Seal S n ap Ring D riv e G e a r B earing D riv e G e a r Stop Ring 3 rd & O / D Speed Clutch Assy Stop Ring O v e rd riv e G e a r Second G e a r Stop Ring 12. 13. 14. 15. 16. 17. 1 8. 1 9. 20. 21. 22. 1st & 2n d S peed Clutch Assy Stop Ring First G e a r R ear M a in B earin g Extension Housing V e n t Plug M a in s h a ft R e tain e r C lip S p e e d o m e te r G e a r R ear O il Seal Reverse Id le r G e a r 23 . 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34 . Reverse Id le r G e a r Bushing Reverse Id le r S h a ft S n ap Ring W o o d ru ff Key Thrust W a s h e r C o u n te rs h a ft Roller B earings C o u n te rs h a ft C o u n te rs h a ft G e a r C o u n te rs h a ft S leeve Expansion Plug S n ap Ring D riv e G e a r Roller B earings MANUAL TRANSMISSIONS 34 1. Main Drive Gear Drive Gear Bearing Retainer 3 Snap Ring-Outer 4. 3rd and 4th Synchronizer Ring 5. 3rd and 4th Synchronizer Collar 6. 3rd and 4th S hift Fork 7. 3rd and 4th Speed S ynchronizer Ring 8. 3rd Speed Gear 9, 2nd Speed Gear 10. 1st and 2nd Synchronizer Assem bly 2 1 1. 12. 13. 14 15. 16. 17. 18. 19. 20. 21. 22. 23. 33 32 Reverse Driven Gear Poppet Spring Poppet Ball S h ift Rail 1st and 2nd S hift Fork 1st Speed Gear T hrust W asher Bearing Snap Ring Speedom eter Drive Gear O utput Yoke Flange Nut Rear Bearing Retainer Oil Seal Rear Bearing Retainer 31 24 25 26. 27. 28. 29. 30. 31. 32, 33 34. 35. 36. 7B-7 30 M ainsh a ft Rear Bearing Rear Bearing Snap Ring Snap Ring C ountershaft C ountershaft Rear Bearing Bearing Snap Ring Reverse Idler Gear Reverse id le r Shaft Case M agnet Spacer C ountergear T hrust W asher Snap Ring 37. Front C ountershaft Bearing 38, C ountergear Front Cover Pilot Bearing Rollers 39 40. Clutch Gear Oil Slinger 41. Snap Ring 42. 3rd Speed Gear Bushing 43. T hrust W asher 44. 2nd Speed Gear Bushing 45. 1st Speed Gear Bushing Fig. 7B-5--4-Speed, 117m m , Cross-Section LIG H T T R U C K S E R V IC E M AN U AL 7B-8 1 MANUAL TRANSMISSIONS Fig. 7B-6--4-Speed 117mm, Exploded View 1. 2. 3. 4. Drive Gear Bearing Retainer Retainer Gasket Lip Seal Snap Ring 5. 6. Drive Gear Bearing 7. Drive Gear and Pilot O il SI in ger Bearings 8. 9. 10. 11. 12. Power Take-O ff Cover Gasket Power Take-O ff Cover Retaining Screws 1st-2nd Speed Blocker Rmg Synchronizer Spring 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 1st-2nd Speed Synchronizer Hub Synchronizer Keys Synchronizer Spring Reverse Driven Gear 1st Gear Bushing 1st Gear Thrust Washer Rear Main Bearing Bearing Snap Ring Speedometer Gear 26. 27. 28. 29. 30. 34 Rear Mainshaft Lock 35. 31. 32, 33. 25. 2nd Speed Bushing (On Shaft) Mainshaft 37. 38. 39. 40. 41. 42. 43. 44. Hub N ut 24. 2nd Speed Gear 3rd Gear Bushing Thrust Washer 3rd Speed Gear 3rd Speed Blocker Ring Synchronizer Spring Synchronizer Keys 3rd-4th Synchronizer 36. Synchronizer Spring 3rd-4th Speed Blocker Ring 3rd-4th Speed Synchronizer Sleeve 45. 46. 47. Snap Ring Snap Ring Thrust Washer Clutch Countergear Spacer 3rd Speed Countergear Countergear Shaft Countergear Rear Bearing Snap Ring Bearing Outer Snap Ring Rear Retainer Gasket 48. 49. 50. 51. 52. 53. 54. 55. 56. 57. 58. 59. Rear Retainer Retainer Bolts Retainer Lip Seal Reverse Idler Shaft Drain Plug Reverse Idler Gear Case Fill Plug Countergear Front Bearing Gasket Front Cover Cover Screws MANUAL TRANSMISSIONS 7B-9 MAINTENANCE AND ADJUSTMENTS TRANSMISSION LINKAGE ADJUSTMENT 3-Speed Column Shift (Fig. 7B-6, 7, and 8) In cases where gearshift linkage has been disconnected or removed, proper adjustm ent sequence is im portant. 1. S et both shifter levers in n eu tral position. Install control rods to both second and third shifter lever and first and reverse shifter lever. 2. Align both shifter tube levers on mast jacket in the neutral position. Install gauge (3/16 to 7/32 in.) in holes of levers so th a t gearshift control lever is in neutral position. 3. Connect control rods to tube levers making sure clamps are properly adjusted so th a t tube levers and transm is­ sion shifter levers rem ain in their neutral positions while tightening. 4. Remove gauge and move selector lever through all positions to check adjustm ent and insure over-travel in all positions. If m ast jacket lower dash clam p has been disturbed at its m ounting on dash, its ad ju stm en t to the steering m ainshaft should be checked as outlined in Section 3B of this m anual. Fig. 7B-7--G-Truck Column Shift Linkage LIGH T T R U C K S E R V IC E M AN U AL 7B-10 S H IF T LEVER ROD J H RELA Y LEVER K F COLUM N CONTROL LEVER R E T A IN E R ROD A G G A G E P IN Fig. 7B-8--C S H IF T L E V E R H ROD F TRANS LEVER and BO LT K-Truck S W IV E L B C D Column Shift Linkage TRANSMISSION CONTROL LINKAGE ADJUSTMENT Set Levers (A ) and (B ) in " R E V E R S E " p o sitio n a n d tu rn ign itio n sw itch to " L O C K " p o sitio n . NOTE O b ta in R E V E R S E " p o sitio n by m o vin g T ra n s Lever (B ) c lo c k w ise to fo rw a rd detent. 2. A tta c h R o d (G ) to S h ift Lever (J) w ith retainer. See V ie w A . S lid e sw ivel (D ) o n to R o d (G ). into Lever (B ) and lo ose ly asse m bly w ith b o lt (C ) a n d w asher at th is tim e. 3. R e m o ve c o lu m n " L A S H " by rotatin g Lever (J) in a d o w n w a r d d ire c tio n and c o m p le te a tta c h m e n t o f R o d (G ) to Lever (B ) by tig h te n in g B o lt (C) u sin g re c o m m e n d e d torque. 4. T u rn ign itio n key to " U N L O C K " p o sitio n an d p o sitio n Levers (A ), (B ) an d (E ) in " N E U T R A L " . NOTE O b ta in " N E U T R A L " p o sitio n by m o vin g Levers (B ) and (E ) c lo c k w ise to fo rw a rd detent then c o u n te r-c lo ck w ise o n e detent. 5. A lig n gage holes in Levers (H), (J) an d (K ) and insert G a ge Pin (L ). 6. R ep eat steps 2 & 3 fo r R o d (F) & Levers (E ) & (H ). 7. R e m o v e Gage Pin (L). NOTE W ith sh ift lever in " R E V E R S E " the ign itio n key m u st m ove freely to " L O C K " p o sitio n . to o b ta in ig n itio n " L O C K " p o sitio n in " N E U T R A L " or a n y gear o th e r tha n " R E V E R S E " . Insert Sw iv e l (D ) It m u st n ot be p ossib le MANUAL TRANSMISSIONS S H IF T L E V E R MANUAL TRANSMISSIONS 7 B -1 1 Fig. 7B-9--P-Truck Colum n Shift Linkage DIAGNOSIS Preliminary Inspection Before attempting to repair the clutch, transmission or related linkages for any reason other than an obvious failure, the problem and probable cause should be identified. A large percentage of clutch and m anual transmission problems are manifested by shifting difficulties such as high shift effort, gear clash and grinding or transmission blockout. When any of these problems occur a careful analysis of these difficulties should be accomplished, and the following checks and adjustments performed in the presented se­ quence before removing the clutch or transmission for repairs. CLUTCH ADJUSTMENT Clutch Free Pedal Travel 1. The clutch free pedal travel adjustment should be made as outlined in Section 7C. 2. Check clutch linkage for lost motion caused by loose or worn swivels, deflection of mounting brackets or damaged cordon shaft. Clutch Spin Down Time 1. Run the engine at a normal idle with transmission in neutral and clutch engaged. 2. Disengage the clutch, wait nine seconds and shift the transmission to reverse. No grinding noise should be heard. A grinding noise indicates incorrect clutch adjustment, lost motion clutch misalignment, or inter­ nal problems such as failed dampers, facings, cushion springs, diaphragm spring fingers, pressure plate drive straps, etc. SHIFT LINKAGE ADJUSTMENT Steering Column Shift Control 1. Remove the shift control rods from the column levers. 2. Check shift effort at the shift control lever knob. (Effort should not exceed 2 lb. with transmission linkage removed.) 3. If binding is felt, refer to the adjustment procedure for the steering column lower bearing in Section 3B. 4. Lubricate all rod and swivel connections and recheck shift effort after installation. 5. If shift linkage is free from binding, the column levers should be checked for end play. A .005" feeler gauge should fit between the levers and control lever. 6. Connect control rods and check steering column control levers for alignment. In neutral, the column control LIG H T T R U C K S E R V IC E M AN U AL 7B-12 MANUAL TRANSMISSIONS S H IFT T O R Q U E 3 -S P D — In ch -P oun ds 76m m 50 Fig. 7 B -10—Shift Torque C hart 1. Hard Shifting - The effort to shift is excessive, but the gears engage. The lever moves with excessive effort throughout the entire travel range. If the static shift effort is high, (clutch depressed, engine not running) the synchronizer sleeve and hubs should be checked for a tight fit. With the three synchronizer keys removed, the sleeve should be loose on the hub. If the hub and sleeve are not a loose fit, replace the synchronizer assembly. lever tangs should line up with the slot in the main control lever. Floor Shift Control All swivels, rods and mountings should be checked for lost motion and repaired or replaced as necessary. Transmis­ sion control levers should be checked for wear and repaired or replaced as necessary. TRANSMISSION SHIFT EFFORT Transmission Shift Effort Checking Procedures 1. Remove the shift rods at the transmission and align the sleeve, blocker ring and gear by shifting into the offending gear and then back into neutral. 2. Check the torque required to shift into gear with an inch pound torque wrench on the shift lever attaching bolt. If more than the specified torque (Fig. 7B-10) is required, the transmission shift lever should be checked for rust or dirt binding the lever. 3. Clean levers, lubricate and recheck the torque value. NOTICE: If at this point in the procedure, it is found that high shift effort or blockout still exists, an anti­ c h a tte r lubricant (positraction additive) should be used. The lubricant is available in plastic bottle and can be squirted into the transmission through the filler plug. Transmission Internal Problems Related to Shift Effort When the above procedures have been checked and the problem still exists, the transmission will have to be removed and disassembled for further diagnosis. There are three basic types of transmission internal problems reflected by shifting effort. 2. Blockout - The lever moves freely until the synchro­ nizer is engaged. Synchronization should be heard to take place, but the gear will not engage. When it does engage, a double bump is generally felt in the lever. The synchronized blocker ring can be damaged by excessive force on gear cones that are finished improperly. The blocker ring material may stick to the synchronizer gear cone causing it to be a yellowish brass color, in streaks, which results in hard shifts when present. The gear cone should be a bright silver color. Polish the gear cone with 400 grit paper to a bright silver when this condition is present. The blocker rings should be replaced if the thread is damaged or worn. 3. Clash - Gear clash is a sound which sometimes occurs when the sleeve and gear chamfers contact each other in the unsynchronized state. T he characteristics of clash are a grating or loud buzzing sound from the transmission. The shift lever load will be lower, but a vibration should be felt. The noise (clash) can be for a short instant or long enough to keep the gear from being engaged. This condition should not be confused with hard shifting or reported as such. Hard shifting and clash are directly opposite conditions. When the clash is slight, the load will build up on the shift lever and then fall off rapidly followed by the grating sound. If the transmission has been clashing, the sleeve ends should be examined for chipping and burrs. If the sleeves are damaged, the synchronizer assemblies and blocker rings should be replaced. Synchronizer sleeve ends should have an angular surface. The surfaces should be even from side to side and the radii indicated should be very small. Any chipping will require synchronizer replacement. Check the synchronizer load. W hen the keys are installed, the spring ends on one side of the hub should be hooked in one key and the spring on the opposite side of the synchronizer should not be hooked on the same key. A definite load should be felt when the sleeve is moved on the hubs with the keys and springs in proper position. LIGHT T R U C K SER V IC E M A N U A L MANUAL TRANSMISSIONS 7B-13 SHIFTING D IFFIC U LTY DIAGNOSIS CONDITION High Shift Effort-Column Shift (Effort exceeds 2 ft. lbs. at lever knob with transmission linkage disconnected.) CORRECTION PROBABLE CAUSE Binding of column levers Adjust column mechanism per Section 3B Steering of the Chassis Service Manual Clean and lubricate all rod and swivel connections. Lever end play exceeds .005 in. Adjust levers Misalignment of column control levers. Adjust levers Gear Clash and binding Improper linkage Adjustment Adjust Shift linkage Lost motion Loose or worn swivels and grommets. Deflection of Mounting Brackets. Loose shift levers. Damaged Cordon Shaft Replace defective parts Fig. 7 B -1 1--Shifting Difficulty D iagn osis Chart LIGH T T R U C K S E R V IC E M A N U A L 7B-14 MANUAL TRANSMISSIONS MANUAL TRANSMISSION DIAGNOSIS CONDITION Slips out of High Gear PROBABLE CAUSE CORRECTION a. Transmission loose on clutch housing b. Shift rods interfere with engine mounts or clutch throw-out lever c. Shift linkage does not work freely; binds d. Damaged mainshaft pilot bearing e. Main drive gear retainer broken or loose f. Dirt between transmission case and and clutch housing g. Misalignment of transmission a. Tighten mounting bolts b. Replace or bend levers and rods to eliminate interference c. Adjust and free up shift linkage h. Stiff shift lever seal i. Pilot bearing loose in crankshaft j. Worn or improperly adjusted linkage Noisy in All Gears a. Insufficient lubricant b. Worn countergear bearings c. Worn or damaged main drive gear and countergear d. Damaged main drive gear or main shaft bearings e. Worn or damaged countergear anti­ lash plate d. Replace pilot bearing e. Tighten or replace main drive gear f. Clean mating surfaces g. Refer to TRANSMISSION ALIGNMENT h. Replace seal i. See Section 6 for brg. fits j. Adjust or replace linkage as required a. Fill to correct level b. Replace countergear bearings and shaft c. Replace worn or damaged gears d. Replace damaged bearings or main drive gear e. Replace countergear Noisy in High Gear a. Damaged main drive gear bearing b. Damaged mainshaft bearing c. Damaged high speed gear synchronizer a. Replace damaged bearing b. Replace damaged bearing c. Replace synchronizer Noisy in Neutral with Engine Running a. Damaged main drive gear bearing b. Damaged or loose mainshaft pilot bearing c. Worn or damaged countergear anti­ lash plate d. Worn countergear bearings a. Replace damaged bearing b. Replace pilot bearings. See Section 6 for bearing fits c. Replace countergear Noisy in all Reduction Gears a. Insufficient lubricant b. Worn or damaged main drive gear or countergear a. Fill to correct level b. Replace faulty or damaged gears Noisy in Second Only a. Damaged or worn second-speed constant mesh gears b. Worn or damaged countergear rear bearings c. Damaged or worn second-speed synchronizer a. Replace damaged gears Noisy in Third Only (Four Speed) a. Damaged or worn third-speed constant mesh gears b. Worn or damaged countergear bearings d. Replace countergear bearings and shaft b. Replace countergear bearings and shaft c. Replace synchronizer a. Replace damaged gears b. Replace damaged countergear bearings and shaft Fig. 7 B -1 2 -M a n u a l Transmission D iagn osis C hart A LIGH T T R U C K SER V IC E M AN U AL MANUAL TRANSMISSIONS 7B-15 MANUAL TRANSMISSION DIAGNOSIS (CONT'D.) PROBABLE CAUSE CORRECTION a. Worn or damaged reverse idler gear or idler bushing b. Worn or damaged reverse gear on mainshaft c. Damaged or worn reverse countergear d. Damaged Shift mechanism a. Replace reverse idler gear assembly CONDITION Noisy in Reverse Only b. Replace reverse gear c. Replace countergear assembly d. Inspect linkage and adjust or replace damaged parts Excessive Backlash in all Reduction Gears a. Worn countergear bearings b. Excessive end play in countergear a. Replace bearings b. Replace countergear thrust washers Main Drive Gear Bearing Retainer Burned or Scored by Input Shaft a. Loose or damaged mainshaft pilot bearing b. Misalignment of transmission a. Replace b taring. See Section 6 for bearing fit b. Align transmission Leaks Lubricant a. Excessive amount of lubricant in transmission b. Loose o r 1 broken main drive gear bearing retainer c. Main drive gear bearing retainer gasket damaged d. Side cover loose or gasket damaged e. Rear bearing retainer oil seal leaks f. Countershaft loose in case g. Shift lever seals leak a. Drain to correct level b. Tighten or replace retainer c. Replace gasket Tighten cover or replace gasket e. Replace seal f. Replace case g. Replace seal d. Fig. 7 B -1 3 --M an u al Transmission D iagnosis C hart B COMPONENT REPLACEMENT TRANSMISSION REPLACEMENT 3-Speed and 4-Speed Transmission Removal (Except K Series) 1. Raise vehicle on suitable hoist and drain lubricant from transm ission. 2. Disconnect speedom eter cable. 3. Remove shift controls from transm ission. Fig. 7B-14--Typicai Transmission Mounting On vehicle equipped with 4-Speed ( 1 17mm) transm is­ sion, remove the gearshift lever using Tool J-8109 as shown in Fig. 7B-15. Press down firmly and rotate tool counterclockwise to release gearshift lever. Place clean lint-free cloth or other suitable covering over opening on transm ission to prevent entry of dirt of foreign m aterial. 4. Disconnect parking brake lever and controls (when used) and back up lam p switch wire. Fig. 7B -15-R em oving G earshift Lever LIGH T T R U C K SE R V IC E M ANU AL 7B-16 MANUAL TRANSMISSIONS 5. Disconnect propeller shaft from transmission as de­ scribed in Section 4A. 6. Position a suitable dolly or jack under the vehicle and adjust to carry the weight of the transmission. 7. Visually inspect to determine if other equipment, lines or brackets must be removed to permit removal of the transmission. Remove crossmember. NOTICE: Be sure to support the clutch release bearing and support assembly during removal of the transmis­ sion main drive gear from the flywheel housing. This will prevent the release bearing from falling out of the flywheel housing when the transmission is removed. 8. Remove transm ission-to-clutch housing mounting bolts. C A U T IO N rW h en rem oving the transmission, do not a llo w th e w e ig h t of th e transmission to hang on the clutch disc hub, as th e disc m a y become distorted, seriously affecting clutch o peration. 9. Move the transmission assembly straight away from the engine, using care to keep the transmission main drive gear shaft in alignment with the clutch disc hub. Refer to Fig. 7B-14. 10. When the transmission is free from the engine, lower the transmission and move from under the vehicle. 11. If desired, a careful check of clutch components should be made after the transmission has been removed. If the clutch requires repair, refer to Section 7C before transmission is reinstalled in the vehicle. 3-Speed and 4-Speed Transmission Installation (Except K Series) 1. Apply a light coating of high temperature grease to the main drive gear bearing retainer and splined portion of transmission main drive gear shaft to assure free movement of clutch and transmission components during assembly. 2. 3. 4. 5. 6. 7. NOTICE: Do not apply an excessive amount of grease in the above areas, as under normal operation this grease could be thrown onto clutch facings resulting in clutch problems. Shift the transmission into high gear. Mount transmis­ sion on dolly or jack and move into position under the vehicle. Avoid springing the clutch when the transmission is being installed to the engine. Do not force the transmis­ sion into the clutch disc hub. Do not let the transmis­ sion hang unsupported in the splined portion of the clutch disc. Align the transmission main drive gear shaft with the clutch disc hub by rotating the transmission companion flange or output yoke. Move the transmission forward, guiding the main drive gear shaft into the clutch disc splines. Install transmission-to-clutch housing mounting bolts and washers. Tighten bolts to specifications. Install crossmember. Connect propeller shaft to transmission as described in Section 4A. Remove transmission jack. Connect parking brake lever and control (if used). Adjust brakes as outlined in Section 5. LIGHT T R U C K SER V IC E M A N U A L 8. R econnect speedom eter cable to a d a p te r at transmission. 9. Reinstall shift controls on transmission. On vehicles equipped with a 3-speed transmission and 4 speed 89mm reconnect shift levers to transmission side cover. On vehicles equipped with a 4-Speed, 117mm transm ission, install gearshift lever using Tool J-8109 as shown in Fig. 7B-15. Press down firmly and rotate clockwise to install gearshift lever. Install transmission floor pan cover and floor mat. 10. If other equipm ent (exhaust pipe, support brackets, etc.) was removed, reinstall these parts. 11. Refill transm ission with lu b ric an t recom m ended in Section 0-B of this m anual. 12. If necessary, ad just clutch or transm ission control linkage to achieve proper transm ission operation. 3-Speed Transmission - "K" Series Removal and Installation 1. Raise vehicle on hoist. 2. Drain transfer case and transm ission. Disconnect the speedom eter cable from speedom eter driven gear fitting. 3. Disconnect propeller shaft front U-joint yoke a t case, and tie up out of way. 4. Remove bolt holding the shift lever control assembly to the adapter assembly. Remove shift lever rod from transfer case shift rail connector link. Push assembly to one side and tie up out of way. 5. Remove the bolts attaching the strut to the right-hand side of the transfer case and also to the engine rear face. Remove the strut. 6. Support transfer case in a suitable cradle. Remove bolts attaching transfer case to adapter, and remove the transfer case. 7. Disconnect shift control rods from the shifter levers at the transmission. 8. Support rear portion of engine. Remove two (2) adapter m ount bolts. 9. Remove the 2 top transm ission to clutch housing cap screws and insert 2 transm ission guide pins, Tool J -l 126 in these holes. 10. Remove the 2 lower transm ission-to-clutch housing cap screws. 11. Slide the transmission and adapter assembly straight back on guide pins until the clutch gear is free of splines in the clutch disc. The use of the 2 guide pins during this operation will support the transmission and prevent dam age to the clutch disc through springing. 12. Remove the transm ission and adapter as an assembly from under the body. 13. Remove adapter from transm ission. 14. To install, reverse removal procedure. 4-Speed Transmission Removal K Series 1. Remove attaching screws from transfer case shift lever boot retainer and remove retainer. MANUAL TRANSMISSIONS 2. Remove attaching screws from transm ission shift lever boot retainer. Slide boot and retainer up lever and remove transm ission shift lever using Tool J-8109 as shown in Fig. 7B-15. 3. Remove floor m at or carpeting from com partm ent. 4. If necessary, remove center floor outlet from heater distributor duct. If equipped with a center console, remove console before proceeding to next step. 5. Remove transmission floor cover attaching screws and cover. R otate cover approxim ately 90° to clear transfer case shift lever while lifting cover from vehicle. 6. Disconnect shift lever rod assembly from transfer case shift rail connecting link. 7. Remove shift lever attaching bolt and shift lever control from adapter. 8. Raise and support vehicle on hoist. Support engine with suitable floor stand. Drain transfer case and transm is­ sion assemblies. 9. Disconnect speedom eter cable from transfer case. 10. Disconnect prop shaft at rear of transfer case and tie up away from work area. 11. Disconnect front prop shaft from transfer case and tie up away from work area. 12. Open lock tabs and remove transm ission m ount-tofram e crossmem ber bolts. 13. Support transm ission and transfer case assembly with suitable floor stand. 14. Remove fram e to crossm em ber bolts and remove crossm em ber from vehicle. R o tate crossm em ber to clear fram e rails. 15. On V-8 engine models, remove exhaust crossover pipe. 16. Remove transm ission to clutch housing attaching bolts. Remove upper bolts first and install transm ission guide pins J -l 126. Use of the guide pins will prevent dam age to the clutch assembly. 17. Slide transm ission rearw ard until m ain drive gear clears the clutch assembly and lower assembly from vehicle. 4-Speed Transmission Installation K Series 1. Position transm ission, with transfer case attached, to the clutch housing. Install bolts attaching transmission to clutch housing. 2. On V-8 models, install exhaust crossover pipe. 3. Position fram e crossm em ber and install retaining bolts. Install bolts retaining adapter assem bly to crossm em ­ ber and transfer case to fram e rail bracket. Torque all bolts to specification. 4. Torque front and rear transfer case yoke lock nuts to specifications. 5. Install front and rear propshafts to transfer case output yokes. 6. Connect the speedom eter cable. 7. Fill transmission and transfer case to proper level with lubricant specified in Section OB. 8. Install transfer case shift lever assem bly and attaching bolt. C onnect shift lever rod to shift rail connector link. 9. Install transm ission floor cover and attaching bolts. 7B-17 10. Install heater distributor duct center outlet. On models with center console, install console and retaining bolts. 11. Install floor mat, transfer case shift lever retainer and attaching screws. 12. Install transmission shift lever, boot and retainer. TRANSMISSION ALIGNMENT In some instances where excessive gear whine or high gear hop out, particularly at 50 mph (80 km/h) and up, are encountered, and after all other probable causes have been checked, an alignment check of the transmission and clutch housing may be helpful. A special tool, on which a dial indicator is mounted, is necessary to check the transmission case rear bore align­ ment. This tool may be made from a new or good used clutch gear which has a good bearing surface on the crankshaft pilot end and at the front main bearing location. The splines on the clutch gear shaft and the teeth on the clutch gear should be ground off so the shaft may be rotated in a clutch disc hub without interference when assembled in the car. Weld a piece of 1/4 in. (6.3m m) rod in the mainshaft pilot bore long enough to extend out the case rear bore. Assemble a good bearing on the clutch gear shaft and secure it with the clutch gear bearing snap ring. Attach a suitable dial indicator to the rod. 1. Remove the transmission from the vehicle and com­ pletely disassemble, except for the reverse idler gear. In any case where the clutch gear pilot or pilot bearing is excessively loose or worn, the pilot bearing should be replaced before checking the transmission case rear bore alignment by the dial indicator method. 2. Carefully install the special tool with the dial indicator in the transmission case with the face of the indicator to the rear of the case and with the tracing finger contacting the I.D. of the case rear bore. Secure in place with a clutch gear bearing retainer. 3. Assemble the transmission case to the clutch housing and tighten the four transm ission mounting bolts securely. Be sure to clean off any paint or other foreign material on the mating faces of the clutch housing and transmis­ sion as any foreign material on these faces will change alignment; also, check carefully for dings or burrs on these m ating surfaces and remove carefully as necessary. 4. Dial indicate the transmission case rear bore and record the indicator readings in the 12, 3, 6 and 9 o'clock positions. It is best to start the reading at the 3, 6, 9 or 12 o’clock position closest to the point where the indicator plunger reaches its m axim um outward travel. Set the dial indicator at " 0 " at this location and then record the 3, 6, 9 and 12 o’clock readings in rotation. 5. Install temporary slotted shims between the transmis­ sion case and the clutch housing in the quantities and at the bolt locations as necessary to bring misalignment at the transmission case rear bore to a miximum of 0.005 in. indicator reading in either the vertical or horizontal direction. LIGH T T R U C K SE R V IC E M ANU AL 7B -18 MANUAL TRANSMISSIONS E X A M PL E: If the maximum indicator reading is at the 12 o’clock position, put shims on the two bottom bolts. 6. After the position and quanity of shims has been determined and recorded the transmission case may be removed. NOTICE: The clutch housing should then be stamped, showing the position where shims are to be installed and the thickness of shims at each location. 7. Inspect the external clutching teeth of the clutch gear and second speed gear. Inspect the second and third speed clutch internal clutching teeth. If the teeth are worn or tapered, even slightly, the gears should be replaced. Reassemble the transmission. 8. Install the transmission assembly to the clutch housing, using the correct num ber of shims at the proper locations as previously determined. Shims are available by unit part number with each unit consisting of the following shims: 4 - .0 0 2 " shims Identification-two corners cut off. 2--.005" shims Identification-one corner cut off. 1- .0 1 0 " shims Identification-all corners square. These special shims have a tab on one end for ease of installation. Do not slot the shims for the permanent installation. REAR OIL SEAL REPLACEMENT 1. Drain lubricant from transmission. 2. Disconnect propeller shaft from transmission as de­ scribed in Section 4A. 3. On 3-speed transmissions and 4-speed 89mm, perform the following replacement procedures: a. Remove slip joint yoke from rear of transmission mainshaft. b. Pry seal out of extension housing or remove oil seal using oil seal remover (J-5859) and slide hammer (J2619) as shown in Fig. 7B-16. c. Coat outer diameter of new oil seal with sealing cement. Install new oil seal using extension housing oil seal installer (J-5154). d. Install slip joint yoke on rear of transmission mainshaft. 4. On 4-speed (117 m m ) transmissions, perform the following: a. Remove parking brake from rear of transmission as described in Section 5, if so equipped. b. Disconnect speedometer cable and remove speedom­ eter driven gear from m ainshaft rear bearing retainer. c. Using flange or yoke holding tool, remove the output yoke or companion flange nut. Pull output yoke or companion flange nut off the mainshaft. d. Support transmission while removing mounting bolts and bearing retainer. Remove mainshaft rear bear­ ing retainer and gasket. Discard gasket. e. Remove oil seal from rear bearing cap. Discard oil seal. f. Coat outer diameter of new oil seal with sealing cement. Install oil seal in rear bearing cup using a suitable installer. Drive seal flush with outside of rear bearing cap, being careful not to damage seal. Use Installer J-22834 with A d a p te r J-22834-1 as re­ quired, as shown in Fig. 7B-16. g. Clean all gasket surfaces, then install the rear bearing cap with a new gasket on the transmission. Tighten cap screws firmly. h. Install output yoke or companion flange on main­ shaft. Using a flange or yoke holding tool install retaining nut. Torque the retaining nut to specification. i. Install speedometer driven gear, then connect speed­ ometer cable. 5. Reconnect propeller shaft to transmission as described in Section 4A. 6. Refill transmission with lubricant recom mended in Section 0B. * SPEEDOMETER DRIVEN GEAR REPLACEMENT 1. Disconnect speedometer cable, then remove lock plate to housing bolt and lock washer and remove lock plate. Insert screw driver in lock plate slot in fitting and pry fitting, gear and shaft from housing. Pry " O " ring from groove in fitting. 2. Install new " O " ring in groove in fitting, coat " O " ring and driven gear shaft with transmission lubricant and insert shaft. 3. Hold the assembly so slot in fitting is toward lock plate boss on housing and install in housing. Push fitting into J-22834-2 J-22834-1 NOTE PARKING BRAKE M O U N T IN G FLANGE J- 22834-2 ONLY Fig. 7B-17--Replacing Rear Bearing Retainer Oil Seal LIGHT T R U C K S E R V IC E M ANU AL MANUAL TRANSMISSIONS DETENT C A M DETENT SP R IN G CAM 2 -3 SHIFT FORK 1ST & REV. SHIFTER SHAFT SHIFT FORK 2 -3 SHIFTER SHAFT DETENT C A M RETAINER R IN G Fig. 7 B - 1 8--Transmission Sid e Cover Assem bly housing until lock plate can be inserted in groove and attached to housing. TRANSMISSION SIDE COVER Replacement/Repair (Fig. 7B-17) 1. Disconnect control rods from levers and back-up lamp wiring. 2. Shift transmission into neutral detent positions before removing cover. Remove cover assembly from trans­ mission case carefully and allow oil to drain. 3. Remove the outer shifter levers. 4. Remove both shift forks from shifter shaft assemblies. Remove both shifter shaft assemblies from cover. Seals around shifter shaft may now be pried out if replace­ ment is required because of damage. 7B-19 5. Remove detent cam spring and pivot retainer " C " ring. Remove both detent cams. 6. With detent spring tang projecting up over the 2nd and 3rd shifter shaft cover opening, install the first and reverse detent cam onto the detent cam pivot pin. With the detent spring tang projecting up over the first and reverse shifter shaft cover hole install the 2nd and 3rd detent cam. 7. Install detent cam retaining " C " ring to pivot shaft, and hook spring into detent cam notches. 8. Install both shifter shaft assemblies in cover being careful not to damage seals. Install both shift forks to shifter shaft assemblies, lifting up on detent cam to allow forks to fully seat into position. 9. Install outer shifter levers, flat washers, lock washers and bolts. 10. Shift shifter levers into neutral detent (center) position and slide cover into place making sure the shift forks are aligned with their respective m ainshaft clutch sliding sleeves. 11. Install cover a tta c hing bolts and tighten evenly to specified torque, then connect wiring. 12. Remove filler plug and add lubricant specified in Section OB to level of filler plug hole. TRANSMISSION FLOOR SHIFT CONTROL LEVER REPLACEMENT (4 SPEED) 1 17mm 1. On K-Series models, remove transfer case shift lever boot retainer atta c h in g screws and retainer from compartment floor. 2. Remove floor covering from vehicle. 3. Remove transmission shift lever boot retainer attaching screws. 4. Slide boot and retainer up on shift lever and remove the transmission shift lever using Tool J-8109 as shown in Fig. 7B-14. 5. To install, reverse removal procedure Steps 1-4. L IG H T T R U C K S E R V IC E M AN U AL 7B-20 MANUAL TRANSMISSIONS SPECIFICATIONS THREE-SPEED 76mm C lu tc h G e a r R e ta in e r to C a s e B o lts ...................................... 20 S id e C o v e r to C a s e B o l t s ............................................................ 20 E x te n s io n to C a s e B o l t s .............................................................. 61 S hift L e v e r to S h ifte r Shaft B o l t s ........................................... 32 L u b r ic a tio n F i l l e r P l u g .............................................................. 17 T r a n s m is s io n C a s e to C lu tch H o u sin g B o l t s ................. 101 C r o s s m e m b e r to F r a m e N u t s .................................................. 32 C r o s s m e m b e r to M ount B o l t s ...................................................54 2 -3 C r o s s O v e r Sh aft B r a c k e t R e ta in in g N u t ................... 24 1 -R e v . S w ivel A ttach in g B o l t .................................................. 27 M ount to T r a n s m is s io n B o l t .....................................................68 N- m . . . . 15 N- m . . . . 15 N« m . . . . 4 5 N- m . . . . 25 N - m . . . . 13 N»m....75 N* m . . . . 25 N * m . . . .4 0 N* m . . . . 18 N» m . . . . 2 0 N - m . . . . 50 ft. f t. ft. ft. ft. ft. f t. ft. ft. ft. ft. lb . lb . lb . lb . lb . lb . lb . lb . lb . lb . lb. N* m . . . . 35 N *m . . . . 3 0 N* m . . . . 45 N* m . . . . 25 N • m . . . . 15 N- m . . . . 75 N - m . . . .25 N* m . . . . 4 0 N- m . . . . 18 N- m . . . . 20 N* m . . . . 50 ft. ft. ft. ft. ft. ft. ft. ft. ft. ft. ft. lb . lb . lb . lb . lb . lb . lb . lb . lb . lb . lb. C lu tc h G e a r B e a rin g R e ta in e r to C a s e B o lts ................. .32 N* m . . . . 2 5 ft. C o v e r to C a se B o l t s .......................................................................27 N- m . . . . 20 ft. E xtension and Retainer to Case B o lts-(U p p e r ) ................27 N* m . . . . 20 ft. - ( L o w e r ) .................40 N* m . . . . 30 f t. L u b r ic a tio n F i l l e r P lu g ................................................................40 N * m . . . .3 0 ft. S hift L e v e r to S h ifte r S h aft N u t ...............................................27 N* m . . . . 20 f t. M o u n t- T o - T r a n s m is s io n B o lts ................................................ .45 N * m . . . . 3 2 f t . lb . lb . THREE-SPEED 77mm C lu tc h G e a r R e ta in e r to C a s e B o l t s .......................................47 T op C o v e r to C a s e B o l t s .............................................................. 40 E x te n s io n to C a s e B o l t s .................................................................61 S h ift L e v e r to S h ifte r Sh aft B o lts ..............................................32 L u b r ic a tio n F i l l e r P lu g . . . . . . ...................................................20 T r a n s m i s s i o n C a s e to C lu tc h H o u sin g B o l t s ................... 101 C r o s s m e m b e r to F r a m e N u ts ..................................................... 32 C r o s s m e m b e r to M ount B o l ts ..................................................... 54 2 -3 C r o s s O v e r Sh aft B r a c k e t R e ta in in g N u t......................24 1 -R e v . S w ivel A ttach in g B o l t ..................................................... 27 M ount to T r a n s m i s s i o n B o l t ....................................................... 68 FOUR-SPEED CH465 117mm LIGHT T R U C K S E R V IC E M ANU AL lb. lb . lb . lb . lb. MANUAL TRANSMISSIONS 7B-21 SPECIAL TOOLS 1. J-1126 Tr a n s m i s s i o n G u i d e Pins 6. J-2228 R ea r B ear in g Press Plates 2. J-8059 R e t a in e r S n a p R in g Pliers 7. J-5590 C lu t c h G e a r B ea rin g Ins ta ll er 3. J-22246 C o u n t e r g e a r L o a d in g T o o l 8. J-9772 C l u t c h G e a r B ea rin g Ins ta ll er 4. J-5778 E x t e n s i o n B ush in g R e m o v e r an d Inst all er 9. J-23096 C l u t c h G e a r R e t a i n e r Seal Insta ller 5. J-5154 E x t e n s i o n Seal In st a ll er Fig. 7B-1ST--3-Speed Special Tools LIG H T T R U C K S E R V IC E M AN U AL 7B-22 MANUAL TRANSMISSIONS 14-16 7. 1. 2. J - 2 142 4 -9 J-8059 P L A T E S A N D PRESS P L A T E J-358-1 J- 5778 J- 2228 REAR B E A R IN G 9. J-933 M A IN D R I V E GEAR W R E N C H 10 . J -1126 TR A N S M IS S IO N G U I D E PINS 11. J- 5590 CLUTCH GEAR B E A R IN G IN STA LL ER 12 . J-9772 CLUTCH GEAR B E A R IN G IN S TA LL E R IN S TA LL E R 13. J -2 3 0 9 6 CLUTCH GEAR 14. J -2 1 4 2 6 REAR E X T E N S IO N SEAL IN S TA LL E R 15. J- 575 2 16. J-23596 T R A N S M IS S IO N H O L D IN G F IX T U R E REAR E X T E N S IO N B US H IN G IN S T A L L E R COUNTER GEAR LO AD IN G TO OLS E X T E N S IO N BUSHING REMOVER AND 5. J-51 54 E X TE N S IO N SEAL IN S TA LL E R 6. J - 5 8 14-01 S P E E D O M E TE R D R IV E GEAR A N D A D A P T E R J- 5814 -15 REMOVER Fig. 7B-2ST-4 Speed (89m m) Special Tools LIGHT T R U C K S E R V IC E M ANU AL HOLDER 8. R E T A I N E R S N A P R IN G P L I E R S 3c. J - 29 7 9 3 4. S P E E D O M E T E R D R I V E G E A R PRESS H A N D L E J-8092 3a. J -2 2 2 4 6 3b. J-22379 J -145 3-01 R E A R B U S H IN G R E M O V E R W I T H PRES S P L A T E S R E T A IN E R SEAL IN S TA LL E R MANUAL TRANSMISSIONS 7B-23 3 1. J--1126 T r a n s m i s s i o n G u i d e Pins 2. J-8059 R e t a i n e r S n a p R in g Pliers 3. 4. J-22246 J-5778 5. J-5154 E x t e n s i o n Seal In st a ll er 6. 7. J-2228 J-5590 R ea r B e a r in g Press Plates C l u t c h G e a r B ear in g In st a ll er C o u n t e r g e a r L o a d in g T o o l 8. J-9772 C l u t c h G e a r B ear ing Ins ta ll er E x t e n s i o n Bu s hi n g R e m o v e r an d In st a ll er 9. J-23096 C l u t c h G e a r R e t a i n e r Seal Ins ta ll er Fig. 7B-3ST--4-Speed ( 1 17mm) Special Tools L IG H T T R U C K S E R V IC E M AN U AL : .ic. .riv:V n'ikft?;! . j rr flv ; ckk-:> ?!ooT' Z^-Cpi. i5 -i.bn-. -Avor: ^ fT) .br-jq6-£~T:2C-S^ .pH CLUTCH 7C-1 S E C T IO N 7 C CLUTCH INDEX G eneral D escription.......................................................... Clutch System s............................................................... D iaphragm T y p e ................................................... . Coil Spring T y p e....................................................... C lutch C ontrols.............................................................. M aintenance and A djustm ents....................................... In sp ectio n .......................................................... ............. Free Pedal A djustm ent................................................ D iagnosis.............................................................................. 7C-1 7C-1 7C-1 7C-2 7C-3 7C-8 7C-8 7C-8 7C-10 Component Parts R eplacem ent..................................... ..7C-11 Prelim inary Inspection................................................. ..7C-11 Clutch Disc and Pressure P la te ..................................7 0 1 1 D iaphragm T y p e .........................................................7C-11 Coil Spring T y p e .........................................................7C-12 P e d a l................................................................................. ..7C-12 C ross-S haft........................................................................7C-14 Special T o o ls....................................................................... ..7C-14 G E N ER A L D E SC R IP T IO N CLUTCH S Y S TE M S DIAPHRAGM SPRING CLUTCH Principal Components The principal parts of a diaphragm -type clutch system are: the driving members, attached to the engine and turning with it; the driven members attached to the transmission and turning with it; the operating members which include the spring or springs and the linkage required to apply and release the pressure which holds the driving and driven members in contact with each other. Figure 7C-1 shows a clutch cutaway so operating members can be seen. Driving Members The driving members of a clutch usually consist of two iron plates or flat surfaces m achined to a sm ooth finish. Iron is desirable because it contains enough graphite to provide some lubrication when the driving m em ber is slipping during engagement. One of these surfaces is usually the rear face of the engine flywheel, and the other is a com paratively heavy flat ring with one side m achined. This part is known as the pressure plate. It is fitted into a steel cover, which also contains some of the operating members, and is bolted to the flywheel. Driven Members The driven m em ber is the clutch disc with a splined hub which is free to slide lengthwise along the splines of the clutch shaft, but which drives the shaft through these same splines. Grooves on both sides of the clutch disc lining prevent sticking of the plate to the flywheel and pressure plate. Suitable frictional facings are attached to each side of the clutch disc by means of brass rivets. These facings must be heat resistant since friction produces heat. The most commonly used factings are made of cotton and asbestos fibers woven or molded together and im pregnated with resin or similar binding agents. Very often, copper wires are woven, or pressed into material to give it additional strength. In order to make clutch engagement as sm ooth as possible and eliminate chatter, the steel segments attached to the splined hub are slightly waved, which causes the contact pressure on the facings to rise gradually as the waved springs flatten out. The clutch disc is provided with a flexible center to absorb the torsional vibration of the crankshaft which would be transm itted to the power train unless it were eliminated. The flexible center takes the form of steel compression springs placed between the hub and the steel plate. The springs perm it the disc to rotate slightly with relation to its hub until the springs are compressed and relative motion stops. Then the disc can rotate slightly backward as the springs decompress. This slight backw ard and forw ard rotation perm itted by the springs allows the clutch shaft to rotate at a m ore uniform rate than the crankshaft, thereby elim inating some of the torsional vibration from the crankshaft and preventing the vibration from being carried back through the transmission. Operating Members The driving and driven members are held in contact by spring pressure. This pressure may be exerted by a onepiece conical or diaphragm spring. In the diaphragm design clutch, the clutch release bearing moves forward against the spring fingers forcing the diaphragm spring to pivot around the pivot ring, dishing the fingers tow ard the flywheel. The outer circumference of the spring now lifts the pressure plate away from the driven disc, through a series of retracting springs placed around the outer circumference of the pressure plate. The clutch release bearing is a ball-thrust bearing contained in the clutch housing, m ounted on a sleeve LIGHT TRU C K SE R V IC E M A N U A L 7C-2 CLUTCH D R IV E N PLATE A S S Y . PRESSURE PLATE A N D COVER ASSY. C LUTCH H O U S IN G COVER C L U T C H RELEASE B E A R IN G C LU TC H FORK C LUTCH H O U S IN G C LU TC H FO RK JALL S TU D Fig. 7C -1~C lu tch Syste m C o m p o n e n ts attached to the front of the transmission case. The release bearing is moved by the clutch fork to contact the release levers and move the pressure plate to the rear, thus separating the clutch driving members from the driven member when the clutch pedal is depressed by the driver. A return spring preloads clutch linkage, removing looseness due to wear, keeping the bearing clear of the spring fingers. The clutch free pedal travel, therefore, will increase with linkage wear and decrease with driven disc wear. The free travel felt at the clutchpedal is release bearing lash. Clutch Spring Operation In diaphragm spring type clutches, a diaphragm spring is used instead of coil springs. It is a conical piece of spring steel punched to give it greater flexibility. The diaphragm is positioned between the cover and the pressure plate so that the diaphragm spring is nearly flat when the clutch is in the engaged position. The action of this type of spring is similar to that of the bottom of an ordinary oil can. The pressure of the outer rim of the spring on the pressure plate decreases as the flat position is passed. The outer rim of the diaphragm is secured to the pressure plate and is pivoted on rings approxim ately 1 inch in from the outer edge so that the application of the pressure at the inner section will cause the outer rim to move away from the flywheel and draw the pressure plate away from the clutch disc, releasing or disengaging the clutch. W hen the pressure is released from the inner section, the oil-can action of the diaphragm causes the inner section to move out, and the movement of the outer rim forces the pressure plate against the clutch disc, LIGHT TRUCK SER V IC E M A N U A L thus engaging the clutch. COIL SPRING CLUTCH The coil spring single plate clutch (Fig. 7C-4) is a dry disc type and no adjustm ent for wear is provided in the clutch itself. An individual adjustm ent is provided for locating each lever in m anufacturing but the adjusting nut is locked in place and should never be disturbed, unless the clutch assembly is dism antled for replacement of parts. W hen the clutch pedal is depressed the release bearing is moved tow ard the flywheel and contacts the inner ends of the release levers, (item 1 in Fig. 7C-5). Each release lever is pivoted on a floating pin which rem ains stationary in the lever and rolls across a short flat portion of the enlarged hole in the eyebolt (item 2). The outer end of each release lever engages the pressure plate lug by means of a strut (3), which provides knife-edge contact between the outer end of the lever and the lug. The outer ends of the eyebolts extend through holes in the stam ped cover (4), and are fitted with adjusting nuts (5) to correctly position the levers. W hen the clutch system is fully engaged, the clutch disc is firmly clamped between the flywheel and the pressure plate by the pressure of the springs. W hen the driver disengages the clutch by depressing the pedal, the release fork is moved on its pivot, and the pressure is applied to the release bearing. The rotating race of the release bearing presses against the clutch release levers and moves them on their pivot pins. The outer ends of the release levers, being fastened to the cover, move the pressure plate to the rear, compressing the clutch springs and allowing driving members to rotate independently of the driven member. The CLUTCH 1. Flywheel 2. Dowel-hole 3. Pilot Bushing 4. Driven Disc 5. Pressure Plate 6. Diaphragm Spring 7C-3 7. Clutch Release Bearing 9. Fork 8. Throwout Bearing 10. Retracting Spring Fi g. 7 C - 2 - - C r o s s - S e c t i o n V i e w o f D i a p h r a g m - T y p e release fork moves only on its pivot, which contacts the clutch fork ball stud. All parts of the clutch system, except the clutch release bearing and collar, rotate with the flywheel when the clutch is engaged. W hen the clutch is disengaged, the release bearing rotates with the flywheel, but the driven plate and the clutch shaft rotate as dictated by the transm ission gear range and vehicle speed. CLUTCH CONTROLS The clutch operating controls for C-K trucks (Fig. 7C6) are a mechanical type consisting of a pendant type pedal, return spring, pedal push rod, cross-shaft, fork push rod, routed vertically, inside the cab, from the pedal lever down through two boots on the toe pan, to the cross-shaft lever. W hen the clutch pedal is depressed, the pedal push rod moves rotating the cross-shaft, pushing the fork push rod rearward, and pivoting the clutch fork to move the release bearing against the clutch release fingers and releasing the clutch. The clutch operating controls for "G " and "P" models are a mechanical type similar to the C-K models. On "G " models (Fig. 7C-7) a pedal pull rod is routed vertically from the clutch pedal lever down through the toe-panel to the cross shaft. W hen the pedal is depressed, the pedal pull rod moves, rotating the cross shaft, pushing the clutch fork rod rearw ard and pivoting the clutch fork. This action moves the release bearing against the clutch release fingers, releasing the clutch. Fig. 7C-3--Clutch Disc "P" model controls (Fig. 7C-8) have an upper pull rod connected from the clutch pedal shaft to a bell crank and a lower pulll rod from the bell crank to the cross shaft. W hen the pedal is depressed, the pull rods are moved rotating the cross shaft and pushing the clutch fork rearward, thus subsequently activating the clutch release mechanism. LIGHT TRUCK SE R V IC E M AN U AL 7C-4 CLUTCH 1. Release Lever 2. E ye bo lt 3. Strut 4. C o ve r 5. A d j u s t i n g N u t Fig. 7 C -5 ~ R e le ase Lever, C oil S p rin g Type Fi g. 7 C - 4 ~ C r o s s - S e c t i o n V i e w o f C o il S p r i n g T y p e U G H T TRU C K SE R V IC E M AN U AL CLUTCH 7C-5 Fig. 7C-6--C-K Clutch Controls LIGHT TRUCK SE R V IC E M A N U A L 7C-6 CLUTCH Fig. 7C -7~G -Truck Clutch Controls LIGHT TR U C K SE R V IC E M A N U A L CLUTCH 7C-7 Fig. 7C-8~P-Truck Clutch Controls LIGHT TRUCK SE R V IC E M A N U A L 7C-8 CLUTCH M A IN T E N A N C E A N D A D J U S T M E N T S CLUTCH LINKAGE INSPECTION P-30 Models W /J 7 6 (Fig. 7C-10) There are several things which affect good clutch operations. Therefore, it is necessary, before performing any major clutch operations, to make prelim inary inspections to determ ine w hether trouble is actually in the clutch. Check the clutch linkage to be sure the clutch releases fully as follows: 1. W ith engine running, hold the clutch pedal approxim ately 1/2" from floor m at and move shift lever between first and reverse several times. If this can be done smoothly, the clutch is fully releasing. If shift is not smooth, clutch is not fully releasing and adjustm ent is necessary. 2. Check clutch pedal bushings for sticking or excessive wear. 3. Check fork for proper installation on ball stud. Lack of lubrication on fork can cause fork to be pulled off the ball. 4. Check for bent, cracked or damaged cross shaft levers or support bracket. 5. Loose or dam aged engine m ounts may allow the engine to shift its position causing a bind on clutch linkage at the cross shaft. Check to be sure there is some clearance between cross shaft, both m ount brackets, and ball studs. 6. Check clutch release bearing end clearance between spring fingers and front bearing retainer on the transmission. If no clearance exists, fork may be improperly installed on ball stud or clutch disc may be worn out. 1. Disconnect clutch fork return spring. 2. Loosen nut "G " at swivel. 3. Move the clutch fork rod against fork to eliminate all clearance between release bearing and clutch fingers. 4. R otate shaft lever until clutch pedal contacts the bum per m ounted on the brake pedal bracket. 5. R otate the fork rod until a clearance of approxim ately 1/4" to 5/16" (.29) is obtained between the shoulder on the fork rod and the adjustm ent nut. 6. Tighten nut "G " against swivel and install clutch return spring. 7. Check free pedal clearance at pedal. Pedal clearance should be 1 3/8" to 1 5 /8 ". Readjust as required. CLUTCH FREE PEDAL TRAVEL ADJUSTMENT Only one adjustm ent is necessary to com pensate for all norm al clutch wear. The clutch pedal should have free travel (m easured at clutch pedal pad) before the release bearing engages the clutch diaphragm spring or levers. Lash is required to prevent clutch slippage which would occur if the bearing was held against the fingers or to prevent the bearing from running continually. A clutch that has been slipping prior to free play adjustm ent may still slip right after the new adjustm ent due to previous heat damage. C, K and P Models (Except P30 W /J 76) 1. Disconnect return spring at clutch fork. 2. R otate clutch lever and shaft assembly until clutch pedal is firmly against rubber bum per on brake pedal bracket. 3. Push outer end of clutch fork rearw ard until release bearing lightly contacts pressure plate fingers or levers. 4. Loosen lock nut and adjust rod length so that swivel slips freely into gauge hole. Increase pushrod length until all lash is removed from system. 5. Remove swivel from gauge hole and insert into lower hole on lever. Install two washers and cotter pin. Tighten lock nut being careful not to change rod length. 6. Reinstall return spring and check pedal free travel. Pedal travel should be 1 3/8" to 1 5/8" on "C-K " models and 1 1/4" to 1 1/2" on "P" models. LIGHT T R U C K SE R V IC E M A N U A L G-Models (Fig. 7C-11) 1. Disconnect clutch fork return spring at fork. 2. Loosen nut "A" and back off from swivel approxim ately 1/2 inch. 3. Hold clutch fork push rod against fork to move release bearing against clutch fingers (push rod will slide through swivel at cross-shaft). 4. A djust nut "B" to obtain approximately 1/4" clearance between nut "B" and swivel. 5. Release push rod, connect return spring and tighten nut "A" to lock swivel against nut "B". 6. Check free pedal clearance at pedal (1 1/4" to 1 1/2" is proper clearance). Readjust if necessary. CLUTCH 7C-9 CROSS SHAFT LEVER PI 0-30 (EXC. MOTOR HOME) Fi g. 7 C - 1 0 - - P - T r u c k F r e e P e d a l T r a v e l INSUFFICIENT CLUTCH RELEASE W here complaints of first or reverse gear clash due to insufficient clutch release are encountered, the following may be helpful. Cut off the existing clutch pedal stop bum per to a height of 3 /8 ". Since shortening the bum per increases the lash and not the usable stroke, the lash must Fi g. 7 C - 1 1 - - G - T r u c k F r e e P e d a l T r a v e l be reduced to specifications in order to gain the additional stroke benefit. LIGHT TRU C K SER V IC E M A N U A L 7C-10 CLUTCH D IA G N O S IS PROBABLE CAUSE CONDITION Fails to Release (Pedal pressed to floor-shift lever does not move freely in and out of reverse gear a. b. c. d. e. f. Improper linkage Adjustment Improper pedal travel Loose linkage Faulty pilot bearing Faulty driven disc Fork off ball stud g. Clutch disc hub binding on clutch gear spline h. Clutch disc warped or bent CORRECTION a. b. c. d. e. f. Adjust Linkage Trim bumper stop and adjust linkage Replace as necessary Replace bearing Replace disc Install properly and* lubricate fingers at release bearing with wheel bearing grease. g. Repair or replace clutch gear and/or disc. h. Replace disc (run-out should not exceed .020"). *Very lightly lubricate fingers Slipping a. Improper Adjustment (no lash) b. Oil Soaked driven disc c. Worn facing or facing torn from disc. d. Warped pressure plate or flywheel e. Weak diaphragm spring f. Driven plate not seated in g. Driven plate overheated Grabbing (Chattering) Rattling-Transmission Click Release Bearing Noise with Clutch Fully Engaged Noisy a. Oil on facing. Burned or glazed facings. b. Worn splines on clutch gear. c. Loose engine mountings. d. Warped pressure plate or flywheel. e. Burned or smeared resin on flywheel or pressure plate. a. Weak retracting springs. b . Clutch fork loose on ball stud or in bear­ ing groove. c. Oil in driven plate damper. d. Driven plate damper spring failure. Replace transmission clutch gear. Tighten or replace mountings. Replace pressure plate or flywheel. Sand off if superficial, replace burned or heat checked parts. a. Replace pressure plate. b. Check ball stud and retaining. c. Replace driven disc. d. Replace driven disc. a. Worn release bearing. b. Fork off ball stud (heavy clicking). a. Replace bearing. b. Install properly and lubricate fork fingers at bearing. c. See Section 6 for bearing fits. Bearing loose in crankshaft. a. Bind in linkage or release bearing. a. Bind in linkage. b. Driven plate worn. Fig. 7C-1 2--Clutch Diagnosis Chart LIGHT TRU C K SE R V IC E M A N U A L b. c. d. e. a. Adjust linkage. b. Clean, relubricate, check for burrs, nicks,etc. c. Replace fork. b. Springs weak in pressure plate. c. Springs being over traveled. Hard Pedal Effort a. Install new disc and correct leak. a. Improper adjustment. No Lash. b. Release bearing binding on trans­ mission bearing retainer. c. Insufficient tension between clutch fork spring and ball stud. d. Fork improperly installed. e. Weak linkage return spring. c. Pilot Pedal Stays on Floor When Disengaged a. Adjust linkage to spec. b. Install new disc and correct leak at its source c. Replace disc d. Replace pressure plate or flywheel e. Replace pressure plate (Be sure lash is checked before replacing plate.) f. Make 30 to 40 normal starts CAUTION: Do Not Overheat g. Allow to cool —check lash d. Install properly. e. Replace spring. a. Lubricate and free up linkage and release bearing. b. Replace pressure plate. c. Adjust linkage to get proper lash, be sure proper pedal stop (bumper) is installed. a. Lubricate and free up linkage. b. Replace driven plate. CLUTCH 7 C -1 1 CO M PONENT PARTS REPLACEM ENT PRELIMINARY INSPECTION There are m any things which affect good clutch operation. Therefore, it is necessary, before performing any major clutch operations, to m ake a prelim inary inspection to determ ine w hether or not the trouble is actually in the clutch. 1. Check the clutch pedal and m ake sure that the pedal has proper free travel, as described in "M aintenance and A djustm ents". 2. Check the clutch pedal bushing for wear and for sticking on the shaft or loose mountings. 3. Lubricate the pedal linkage. 4. Tighten all front and rear engine m ounting bolts. CLUTCH DISC AND PRESSURE PLATE (DIAPHRAGM TYPE) Removal from Vehicle 1. Remove transmission as outlined in Section 7B. 2. Disconnect clutch fork push rod and pull back spring. 3. Remove clutch and flywheel housing. 4. Remove clutch fork by pressing it away from its ball m ounting with a screwdriver, until the fork snaps loose from the ball or remove ball stud from rear of clutch housing. Remove release bearing from clutch fork. NOTICE: The retainer may be removed from the fork by prying out with a small screwdriver. 4. Install clutch disc, pressure plate and cover assembly and support them with Tool J-5824 or a used clutch drive gear. 5. T urn clutch assembly until "X" mark or painted white letter on clutch cover flange lines up with "X" mark on flywheel. 6. Install attaching bolts and tighten each one a turn at a time to prevent distorting the cover as the spring pressure is taken up. 7. Remove clutch pilot tool. 8. Pack clutch fork ball seat with a small am ount of high melting point grease. On "P" models with J76, install a new retainer in the groove of the clutch fork if the old retainer is worn or damaged. NOTICE: Install retainer with high side up, away from bottom of the ball socket and with open end of retainer on the horizontal. CAUTION: Be careful not to use too much lubricant. Excessive lubricant may get on clutch fingers and cause slippage. 9. Replace clutch fork ball if removed from the clutch housing and snap clutch fork onto the ball. 10. Pack lubricant in the recess on the inside of the release bearing collar and coat the clutch fork groove with 5. Install Tool J-5824 or a used clutch drive gear to support the clutch assembly during removal. NOTICE: Before removing clutch from flywheel, m ark the flywheel, clutch cover and one pressure plate lug, so that these parts may be assembled in their same relative positions, as they were balanced as an assembly. 6. Loosen the clutch attaching bolts one turn at a time to prevent distortion of clutch cover until diaphragm spring is released. 7. Remove clutch pilot tool and remove clutch assembly from vehicle. NOTICE: The flywheel should be inspected for cracks, heat checking, flatness and other defects. Installation to Vehicle 1. Install the pressure plate in the cover assembly lining up the notch m ark on pressure plate with notch m ark on flange of cover. 2. Install pressure plate retracting springs, lockwashers and drive strap to pressure plate bolts. Tighten to 11 ft. lbs. torque. The clutch is now ready to be installed. 3. H and crank the engine until "X" m ark on flywheel is at the bottom. L IG HT TR U C K SER V IC E M A N U A L 7C-12 CLUTCH a small am ount of graphite grease, as shown in Figure 7C13. 11. Install release bearing assembly to the clutch fork. Install clutch and flywheel housing to engine. 12. Assemble transm ission as outlined in Section 7B. 13. Align push rod to clutch fork and attach return spring to clutch fork. 14. Adjust clutch linkage as described in "M aintenance and A djustm ents." CLUTCH DISC AND PRESSURE PLATE (COIL SPRING TYPE) Removal From Vehicle 1. Remove transm ission as outlined in Section 7B. 2. Disconnect clutch fork push rod and pull back spring. 3. Remove clutch and flywheel housing. 4. Remove clutch fork by pressing it away from its ball mounting with a screwdriver, until the fork snaps loose from the ball or remove ball stud from rear of clutch housing. Remove release bearing from clutch fork. NOTICE: The retainer may be removed from the fork by prying out with a small screwdriver. 5. Install Tool J-5824 or a used clutch drive gear to support the clutch assembly during removal. NOTICE: Before removing clutch from flywheel, m ark the flywheel, clutch cover and one pressure plate lug, so that these parts may be assembled in their same relative positions, as they were balanced as an assembly. 6. Loosen the holding screws a turn or two at a time to avoid bending rim of cover. It is advantageous to place wood or metal spacers (approxim ately 3/8 thick) between the clutch levers and the cover to hold the levers down as the holding screws are removed or when clutch is removed from engine. W hen removing driven plate be sure to m ark flywheel side. 7. Remove clutch pilot tool and remove clutch assembly from vehicle. NOTICE: Inspect flywheel for heat defects, cracks, flatness, or other defects. Installation To Vehicle 1. Assemble driven plate and clutch cover assembly to flywheel in accordance with marking on driven plate for flywheel side. Use Tool J-5824 or a dum m y shaft to support assembly. 2. Line up the clutch assembly with "X" m ark or painted white letter with "X" m ark on flywheel, before tightening cover holding screws. 3. Tighten holding screws, a turn at a time, before removing dum m y shaft. 4. Remove clutch pilot tool. 5. Pack clutch fork ball seat with a small am ount of high melting point grease and install a new retainer in the groove of the clutch fork if the old retainer is worn or damaged. L IG HT TRU C K SE R V IC E M A N U A L NOTICE: Install retainer with high side up, away from bottom of the ball socket and with open end of retainer on the horizontal. CAUTION: Be careful not to use too much lubricant. Excessive lubricant may get on clutch fingers and cause slippage. 6. Replace clutch fork ball if removed from the clutch housing and snap clutch fork onto the ball. 7. Pack lubricant in the recess on the insde of the release bearing collar and coat the clutch fork groove with a small am ount of graphite grease, as shown in Figure 7C13. 8. Install release bearing assembly to the clutch fork. Install clutch and flywheel housing to engine. 9. Assemble transmission as outlined in Section 7B. 10. Align push rod to clutch fork and attach return spring to clutch fork. 11. A djust clutch linkage as described in "M aintenance and A djustm ents." CLUTCH PEDAL ARM, PUSH ROD OR BUSHING REPLACEMENT (Fig. 7C-14) C-K Models Removal 1. Disconnect battery negative ground cable at the battery terminal. 2. D isconnect clutch push rod at the cross shaft under the vehicle. 3. Remove steering colum n covers. Remove screws retaining push rod boots to bulkhead. 4. Remove air conditioning duct from lower left side of instrum ent cluster is so equipped. (Refer to Section 1A). CAUTION: Maintain pressure on lower arm. When lower attaching bolt is removed upper section will snap upward. 5. Disconnect clutch neutral start switch from pedal arm. 6. Remove bolts attaching lower section of clutch pedal arm to the upper arm. 7. Remove lower arm and push rod from vehicle. 8. Remove pedal return spring. 9. Remove pedal pivot shaft retaining nut and pivot shaft. Insert a dum m y shaft or rod through the support to hold the brake pedal com ponents in place. 10. Remove the clutch pedal assembly from the support assembly. 11. Remove pedal bushings and spacer from pedal arm. Check pedal bum per for wear and replace as required. Installation 1. Install new bushings and spacer in pedal arm. Com ponents should be lubricated prior to assembly. 2. Position clutch pedal upper arm in support bracket and install pivot bolt through support and pedal arms. NOTICE: Bolt must be installed in direction shown in CLUTCH 7C-13 Figure 7C-14 in order to clear return spring. 3. Install pivot bolt retaining nut and torque to specifications. 4. Install pull back spring to support and pedal arm. NOTICE: If previously removed connect pedal push rod to clutch pedal arm. 5. Position lower pedal arm to upper arm and install upper attaching bolt. Push down on pedal and install lower bolt. Torque to specifications. 6. Install clutch neutral start switch. 7. Install air conditioning duct. 8. Install steering column covers. Install screws retaining push rod boots to bulk head. 9. Check operation of clutch assembly and adjust clutch as required. G and P Models (Fig. 7C-14) Removal 1. Apply parking brake firmly. Disconnect neutral start switch from pedal arm. 2. Remove bolt at clutch pedal push rod lever, then remove lever from pedal shaft. 3. Hold pedal pad with one hand and slide clutch pedal and shaft assembly outboard enough to clear pedal stop. Insert a dum m y shaft or rod through support and brake pedal assembly to hold com ponents in place while removing clutch pedal shaft. Allow return spring (or center spring) to pull pedal up high enough to unhook spring from pedal arm. 4. Remove pedal and shaft assembly from support bracket. Inspection 1. Check clutch pedal bushings for excessive wear and replace as necessary. 2. Check clutch pedal shaft for wear and alignment. Straighten or replace as necessary. Installation NOTICE: Use new shaft bushing if needed. Lubricate with petrolatum . 1. Slide one pedal shaft bushing over shaft, install shaft in support enough to still clear pedal bum per stop, hook pedal return (or overcenter) spring to pedal, then rotate pedal forward of bum per stop; slide shaft into position in support and release pedal against bum per stop. 2. Install clutch pedal shaft bushing over pedal shaft end and into place in sleeve. 3. Assemble pedal push rod lever over pedal shaft and install bolts, washers, and nut. 4. Connect neutral start switch to pedal arm. 5. A djust clutch pedal free travel as needed. Fig. 7 C -1 4 -C lu tc h Pedal M ou nting Attachm ent LIG HT TRUCK SE R V IC E M A N U A L 7C-14 CLUTCH CLUTCH CROSS-SHAFT REPLACEMENT u „ J ^ ^ , bail stud. On G models, remove rrome bracket retaining bolts, then remove shaft from engine ball stud. (Figs. 7 C -6 , 7 C -7 , 7 C -8 ) 1. Disconnect clutch fork return spring at fork. 2. Disconnect pedal push rod at cross-shaft lever and allow clutch fork push rod to hang free from lower lever. 4. Remove clutch fork push rod from cross-shaft lever. 3. On C-K models, remove ball stud retaining nut, at frame end and slide shaft tow ard engine. Then lift crossshaft up to clear bracket and remove shaft from the engine 5. Reverse removal procedure to install. S P E C IA L T O O LS 1.J-6456-01 Height Gauge 2. J 1048 Gauge Plate 3. J-1522 Pilot Bearing Driver 4. J-23720 Clutch Pilot Tool 5. J-1448 Pilot Bearing Puller Fi g. 7 C - S T ~ C l u t c h S p e c i a l T o o l s LIG HT TR U C K SE R V IC E M A N U A L TRANSFER CASE 7E-1 SECTION 7E TRANSFER CASE CONTENTS Model 208 T ransfer Case (10 and 20 S e rie s).......................................... Model 205 T ransfer Case (30 S eries)........................................................ Specifications.................................................................................................... Special T ools..................................................................................................... 7E-1 7E-9 7E-15 7E-16 MODEL 208 TRANSFER CASE (10 AND 2 0 SERIES-ALUMINUM CASE) INDEX G eneral D escription........................................................................................ .7E-1 D iagnosis.............................................................................................................7E-4 M aintenance and A d ju stm en ts.....................................................................7E-4 On Vehicle S e rv ic e ......................................................................................... .7E-8 T ransfer Case R em oval............................................................................ .7E-8 T ransfer Case Installation........................................................................ ..7E-8 GENERAL DESCRIPTION MODEL 208,PART TIME (ALUMINUM CASE) The Model 208 transfer case (as shown in Fig. 7E-1) is an alum inum case, chain drive, four position unit providing four-wheel drive high and low ranges, a two-wheel high range, and a neutral position. The model 208 is a part-tim e four-wheel drive unit. Torque input in four-wheel high and low ranges is undifferentiated. The range positions on the Model 208 are selected by a floor m ounted gearshift lever. Models equipped with the 208 transfer case are also with au to m atic locking front drive hubs as stan d a rd equipm ent. The Model 208 case is a two-piece alum inum case containing front and rear output shafts, two drive sprockets, a shift m echanism and a planetary gear assembly. The drive sprockets are con- nected and operated by the drive chain. The planetary assembly which consists of a four pinion carrier and an annulus gear provide the four-wheel drive low range when engaged. Reduction ratio is 2.61:1 in this range. LIGH T T R U C K S E R V IC E M ANU AL 7E-2 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. TRANSFER CASE INPUT GEAR THRUST WASHER INPUT GEAR THRUST BEARING INPUT GEAR MAINSHAFT PILOT BEARING PLANETARY ASSEMBLY PLANETARY THRUST WASHER ANNULUS GEAR ANNULUS GEAR THRUST WASHER NEEDLE BEARING SPACERS MAINSHAFT NEEDLE BEARINGS (120) NEEDLE BEARING SPACER SPACER WASHER OIL PUMP GEAR SPEEDOMETER GEAR DRIVE SPROCKET SNAP RING DRIVE SPROCKET BLOCKER RING SYNCHRONIZER SLEEVE SYNCHRONIZER SPRING SYNCHRONIZER KEY SYNCHRONIZER HUB SYNCHRONIZER HUB SNAP RING MAINSHAFT MAINSHAFT THRUST BEARING INTERNAL GEAR SNAP RING MODE FORK BUSHING(SHIFT ROD SPRING SPRING RETAINER RANGE FORK PADS RANGE FORK RANGE SECTOR 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 53. 54. 55. 56. MODE FORK BRACKET REAR CASE SEAL PUMP HOUSING REAR RETAINER BEARING SNAP RING REAR OUTPUT BEARING VENT TUBE REAR SEAL DRAIN AND FILL PLUGS FRONT OUTPUT SHAFT REAR BEARING FRONT OUTPUT SHAFT REAR THRUST BEARING RACE (THICK) CASE MAGNET FRONT OUTPUT SHAFT REAR THRUST BEARING FRONT OUTPUT SHAFT REAR THRUST BEARING RACE (THIN) DRIVEN SPROCKET RETAINING RING DRIVE CHAIN DRIVEN SPROCKET FRONT OUTPUT SHAFT FRONT OUTPUT SHAFT FRONT THRUST BEARING RACE (THIN) FRONT OUTPUT SHAFT FRONT THRUST BEARING RACE (THICK) FRONT OUTPUT SHAFT FRONT BEARING FRONT OUTPUT SHAFT FRONT THRUST BEARING OPERATING LEVER Fig. 7E-1 M o d el 2 0 8 Transfer Case LIGH T T S U C K s e r v i c e m a n u a l 57. WASHER AND LOCKNUT 58. RANGE SECTOR SHAFT SEAL RETAINER 59. RANGE SECTOR SHAFT SEAL 60. DETENT BALL, SPRING AND RETAINER BOLT 61. FRONT SEAL 62. FRONT YOKE 63. YOKE SEAL WASHER 64. YOKE NUT 65. INPUT GEAR OIL SEAL 66. INPUT GEAR FRONT BEARING 67. FRONT CASE 68. LOCK MODE INDICATOR SWITCH AND WASHER 69. INPUT GEAR REAR BEARING 70. LOCKPLATE 71. SHIFTER FORK SHAFT 72. LOCKPLATE BOLTS 73. CASE ALIGNMENT DOWELS TRANSFER CASE 7E-3 Shift Pattern REAR YOKE A floor m ounted shift lever is used to select the various operating ranges on the 208 model. The shift lever is located on the floorpan transm ission tunnel adjacent to the tran s­ mission gearshift lever. Furtherm ore, the transfer case shift pattern is not in a straight line for 208 models, the range positions are shown in Fig. 7E-2. IDENTIFICATION TAG DRAIN FILL PLUG Four-Wheel Drive Indicator Lamp An indicator lamp is mounted in the instrum ent panel to alert the driver whenever the vehicle is being operated in four-wheel range. The lamp is controlled by an indicator switch in the transfer case (Fig. 7E-3). The switch is a ball and plunger unit that is activated by the transfer case range sector when four-wheel range is selected. Identification An identification tag is attached to the rear half of the transfer case (Fig. 7E-3). This tag provides the transfer case model num ber, low range reduction ratio, and assembly num ber. The inform ation on this tag is necessary for servicing inform ation. If the tag is removed or becomes dislodged during service operations, it should be reattached using an adhesive sealant such as Loctite 312, or equivalent. INDICATOR SWITCH Fig. 7E-3 M o d e l 208 Indicator Switch, Identification Tag, an d Drain an d Fill Plug Location and adjustm ents section for lubricant change procedures and fill level. Power Flow Lubrication The M odel 208 tran sfer case lu b rican t should be changed at the intervals specified in the M aintenance Schedule. W hen adding lubricant to or refilling the transfer case after service, use Dexron® II. Refer to the m aintenance In all drive range positions input torque is transm itted to the transfer case gear train through the transfer case input gear. In 2H range, torque flows from the input gear to the planetary assembly and annulus gear which rotate as a unit. Torque is transferred to the m ainshaft through the plane­ tary carrier which is splined to the m ainshaft. Torque flow continues through the m ainshaft and rear yoke which is splined to the m ainshaft, and finally to the rear propeller shaft and axle. In 2H range, the sliding clutch rem ains in a neutral position and does not lock the drive sprocket to the m ainshaft. As a result, torque is not transferred to the driven sprocket. In 4H range, input torque from the input gear is transm itted through the planetary and annulus gear and through the m ainshaft in exactly the same fashion as in 2H range. However, in 4H position, the sliding clutch is shifted forward and into engagem ent with the m ainshaft clutch gear. This locks the drive sprocket to the m ainshaft through the sliding clutch. Torque is now transm itted through the drive sprocket to the driven sprocket by the connecting drived chain. Since the front output shaft is splined to the driven sprocket, torque now flows through the front output shaft to the front propeller shaft and axle resulting in high range four-wheel drive. In 4L range, the path of torque through the transfer case is exactly the same as in 4H range but with one major LIGH T T R U C K SER V IC E M ANU AL 7E-4 TRANSFER CASE difference. In 4L range, the annulus gear is shifted forward and into engagem ent with the lock plate. Since the lock plate is fixed in the case, the annulus gear is held stationary and does not rotate. This causes the planetary pinions to rotate about the annulus gear internal teeth producing a gear reduction ratio of 2.61:1. SERVICE DIAGNOSIS GENERAL Before attem pting to repair a suspected transfer case m alfunction, check all o th er driveline com ponents. The actual cause of a problem may be related to such items as the front hubs, axles, propeller shafts, wheels and tires, transm ission, or clutch instead. If all other driveline components are in good condition and operating properly, refer to the Service Diagnosis C h art for further inform ation. MAINTENANCE AND ADJUSTMENTS CASE-OIL CHANGE 1. 2. 3. 4. 5. 6. Raise vehicle. Position drain pan under transfer case. Remove drain and fill plugs and drain lubricant. Install drain plug. Tighten plug to 18 ft. lb.(24 N-m). Remove drain pan. Fill tra n sfe r case to edge of fill plug opening with Dexron® II. 7. Install fill plug. Tighten plug to 18 ft. lb. (24 N-m). 8. Lower vehicle. LIGH T T R U C K S E R V IC E M AN U AL LINKAGE ADJUSTMENT AND INSPECTION T he control linkages and a ttach m en ts for the 208 transfer case are shown in Fig. 7E-4 and 7E-5. Periodically inspect the linkage system for freedom of operation, proper engagem ent, loose attaching bolts, foreign m aterial, etc. A djust, clean and tighten as necessary. TRANSFER CASE 7E-5 Fig. 7E-4 Transfer Case Linkage Skid Plates and Strut Rods LIGH T T R U C K S E R V IC E M AN U AL 7E-6 TRANSFER CASE WITH AUTOMATIC TRANSMISSION WITH MANUAL TRANSMISSION Fig. 7E-5 Transfer Case Attachments LIGH T T R U C K S E R V IC E M ANU AL TRANSFER CASE 7E-7 Service Diagnosis Condition .awn* u# vo * Possible Cause T R A N S FE R CASE (1) Vehicle speed to o great to perm it shifting. D IFF IC U L T TO SH IFT . O R WILL NOT SH IFT cniilj Off) t?flfegri INTO D ESIRED RANGE bnjd n ft! 10 usihob ? icy, (2) If vehicle was o perated for extended period in 4H m ode on dry paved ^ i^ J n p jrfg iT surface, driveline to rq u e load may cause difficult shifting. > roforisi'i '4'i.a'jg novi 1*11.**•ft)0 h 0 1 r:’i;K (3) T ransfer case external shift linkage na:,- 1 * ;1 V, pj feJiBila iai[: qO’iC binding. , i ,'i/fs uz " 4j i grti^ij as A? / -u. - m r i c / . " . ;T i t t/m -"i grtr, - i (4) Insufficient or incorrect lubricant. isb n u iTTO* 1 br ^j/ l7oqc5c-a*:vcni.v.>i (5) Internal com ponents binding, w orn, or damaged. •> i)f >l*nivU;i no a$i& ishnuii o. Ju’}j (1) Insufficient or incorrect lubricant. T R A N SFE R CASE NOISY IN ALL DRIVE MODES NOISY I N - O R JUMPS OUT O F FOUR WHEEL D RIV E LOW RANGE LUBRICANT LEAKING FROM OUTPUT SHAFT SEALS OR FROM VENT ABNORMAL TIR E WEAR Correction (1) S top vehicle and shift into desired range. Or reduce speed to 2-3 m ph (3-4 k m /h) before attem p tin g to shift. (2) Stop vehicle, shift transm ission to n eutral, shift transfer case to 2H m ode and o p erate vehicle in 2H on dry paved surfaces. (3) L ubricate or repair or replace link­ age, or tighten loose com ponents as necessary. (4) Drain and refill to edge of fill hole w ith DEXRON®-II only. (5) Disassemble un it and replace w orn or dam aged com ponents as necessary. (1) D rain and refill to edge of fill hole w ith DEXRON®-II only. Check for leaks and repair if necessary. N ote: If u n it is still noisy after drain and refill, disassem bly and inspection m ay be required to locate source of noise. (1) T ransfer case n o t com pletely engaged in 4L position. (1) S top vehicle, shift.transfer case in N eutral, th en shift back into 4L position. (2) S hift linkage loose or binding. (2) T ighten, lubricate, or repair linkage as necessary. (3) Range fork cracked, inserts w orn, or fork is binding on shift rail. (3) D isassemble u n it and repair as necessary. (4) A nnulus gear or lockplate w orn or damaged. (4) Disassemble u n it and repair as necessary. (1) Transfer case overfilled. (1) Drain to correct level. (2) V ent closed or restricted. (2) Clear or replace vent if necessary. (3) O u tp u t shaft seals dam aged or installed incorrectly. (3) Replace seals. Be sure seal lip faces interior o f case when installed. Also be sure yoke seal surfaces are n o t scored or nicked. Rem ove scores, nicks w ith fine sandpaper or replace yoke(s) if necessary. (1) E xtended o peration on dry hard surface (paved) roads in 4H range. (1) O perate in 2H on hard surface (paved) roads. -Fig. 7E-6-Service Diagnosis Chart LIGHT T R U C K S E R V IC E M A N U A L 7E-8 TRANSFER CASE ON VEHICLE SERVICE 2. Shift transfer case to 4H position if not done previously. TRANSFER CASE REMOVAL 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. Place transfer case in 4H. Raise vehicle. D rain lubricant from transfer case. Remove cotter pin from shift lever swivel. M ark transfer case front and rear output shaft yokes and propeller shafts for assembly alignm ent reference. D isconnect speedom eter cable and indicator sw itch wires. Disconnect front propeller shaft at transfer case yoke. D isconnect p arking brak e cable guide from pivot located on right fram e rail, if necessary. Remove engine stru t rod from transfer case on auto­ m atic transm ission models. Place support under transfer case and remove transfer case-to-transm ission adapter bolts. Move transfer case assembly rearw ard until free of transm ission output shaft and remove assembly. Remove all gasket m aterial from rear of transmission adapter housing. TRANSFER CASE INSTALLATION 1. Install tran sm issio n -to -tran sfer transm ission. LIGH T T R U C K SE R V IC E M A N U A L case gasket on 3. R otate transfer case output shaft (by turning yoke) until transm ission output shaft gear engages transfer case input shaft. Move transfer case forward until case seats against transmission. Be sure the transfer case is flush against the transm ission. Severe dam age to the tran sfer case will result if the atta ch in g bolts are tightened while the transfer case is cocked or in a bind. 4. Install transfer case attaching bolts. Tighten bolts to 30 ft.lb. (41 N-m). 5. Connect speedometer driven gear to transfer case. 6. Connect front and rear propeller shafts to transfer case. Be sure to align shafts-to-yokes using reference m arks m ade duri ng rem oval. T ighten shaft-to-yoke clam p strap nuts to 15 ft.lb. (20 N-m ). 7. Remove support stand from under transfer case. 8. Connect parking brake cable if disconnected. 9. A ttach cotter pin to shift lever swivel. 10. Connect engine strut to transfer case on autom atic models. ® 11. Fill transfer case with Dexron II. 12. Lower vehicle. TRANSFER CASE 7E-9 MODEL 205 TRANSFER CASE (30 SERIES) CONTENTS G eneral D escription........................................................................................ M aintenance and A d ju stm e n ts.................................................................... D iagnosis............................................................................................................ On Vehicle S e rv ic e ........................................ ..................... ........................... T ransfer C ase............................................................................................... Skid P la te ...................................................................................................... S tru t R o d ...................................................................................................... A dapter A ssem blies.................................................................................... 7E-9 7E-11 7E-11 7E-12 7E-12 7E-12 7 E -12 7E-12 GENERAL DESCRIPTION MODEL 205 TRANSFER CASE (30 SERIES) A transfer case mounts behind the transmission and allows drive torque to be transm itted in a proportional split to both the front axle and the rear axle, resulting in fourwheel drive. The shift control lever for the transfer case is floor-mounted in the passenger com partm ent. Depending on the type of transfer case and the shift lever position, various com binations of rear wheel drive, four wheel drive, high traction (gear reduction) or direct drive may be selected. The model 205 transfer case shown in Fig. 7E-7 is a two-speed unit which can be used for either two-wheel or four-wheel drive. Direct drive (1:1 ratio) is available in two modes, 2H for two-wheel drive, or 4H for four-wheel drive. G ear reduction (1.96:1 ratio) is used in the 4L position. This unit uses constant mesh helical gears to connect the input shaft, idler gear and two output gears, thus allowing gear selection to m atch driving conditions. The front input shaft gear (Item # 2 7 ) is in constant mesh with the idler gear ( # 4 4 ) and, through the idler gear, with the front output gears ( # 5 9 and # 6 7 ) and the rear output gear ( # 1 7 ) . S liding clutches ( # 2 6 , # 6 4 ) allow for selective gear engagem ent resulting in High or Lo range, and two-wheel or four-wheel drive. Ball bearings support the input shaft, rear output shaft and front output shaft. Tapered roller bearings are used on the idler shaft. W hen driving in a four-wheel mode (4L or 4H ) the hubs on the front wheels must be turned to the "L ocked" position. LIG H T T R U C K S E R V IC E M ANU AL 7E-10 TRANSFER CASE 1. Rear O u tp u t S h a ft L o c k n u t 26 S lid in g C lu tch 49 Cover Gasket 2 W asher 27 In p u t S h a ft 3 4 Yoke B e a r i n g R e t a i n e r a n d Se a l 28 29 Fro n t O u tp u t S h a ft L o c k n u t W asher A ss e m b ly 5 S n a p R in g 30 31 T ra n s fe r Case P o p p e t P lu g , S p r i n g a n d Ba ll P T 0 G a ske t and C over 50 5 1 52 6 7 B e a rin g S p e e d o m e te r Gear 9 Gasket 10 11 12 13 14 15 In p u t S h a ft B e a rin g and Snap R ing O R ea r C o v e r 53 54 Yoke 55 56 57 Gasket S n a p R in g B e a rin g R etain e r and Seat 32 S n a p R in g a n d R u b b e r R ing S h i f t L in k C le v i s Pm 58 Thrust W a sh e r H ou sin g 33 34 Gasket 35 R a n g e S h i f t Rail S h i f t Rail C o n n e c t o r L in k 59 60 Front W h e e l H ig h G ear F ro n t O u tp u t S h a ft B earing 36 F r o n t W h e e l D r iv e S h i f t Rail 61 S n a p R in g 37 I n t e r l o c k Pins 62 N ee d le B e a rin g s Spacer T hrust W a sh er 38 N eedle B e a rin g 39 Rear Id ler L ock N ut W asher 63 T h r u s t W a s h e r L o c k Pin 64 S lid in g C lu tc h G ear 16 T h r u s t W a s h e r (Ta n ge d ) S h ift Fork Low S peed Gear S h i f t Rail S e a ls Idler S h a ft B e a rin g 65 17 40 4 1 66 Roll Pm 18 N eedle B e a rin g s 42 Bearing Cup 67 Front O u tp u t L ow Gear 19 Spacer 43 44 S h im s Idler Gear 68 20 69 T h r u s t W a s h e r L o c k Pin T hrust W a sh er Front B earing 2 1 N ee d le B e a rin g s Tanged W asher 45 Bearing Cup 70 S n a p R in g 22 Rear O u tp u t S h a ft 46 Spacer 71 Rear C o v e r G a s k e t 23 24 N ee d le B e arings 47 Idler S h a ft B earing 72 Re a r C o v e r a n d B e a r i n g W a s h e r and R etainer 48 Idler S haft 25 S h i f t F o rk Fig. 7E-7--M odel 2 0 5 Transfer Case, Exploded View LIGHT T R U C K SE R V IC E M ANU AL TRANSFER CASE 7E -11 MAINTENANCE AND ADJUSTMENTS LUBRICATION INFORMATION R efer to Section OB of this m anual for detailed inform ation on recom m ended intervals and types of lubricant. LINKAGE ADJUSTMENT AND INSPECTION The control linkage for the transfer part-tim e case is shown in Fig. 7E-8. Periodically inspect the linkage system for freedom of operation, proper engagem ent, loose a ttac h ­ ing bolts foreign m aterial, etc. A djust, clean and tighten as necessary. DIAGNOSIS COMPLAINT Excessive Noise POSSIBLE CAUSES 1. 2. 3. 4. 5. 6. Shifter Lever Difficult to Move Shifter Lever Disengages from Position 1. 2. 1. 2. 3. 4. Lubricant Leaking 1. 2. 3. 4. Lubricant level-low Worn or damaged bearings Worn or damaged chain Misalignment of drive shafts or universal joints Yoke bolts loose Loose adapter bolts Dirt/contamination on linkage Binding inside transfer case Linkage misadjusted/loose Gears worn or damaged Shift rod bent Missing detent ball or spring Excessive lubricant in case Leaking seals or gaskets Loose bolts Scored yoke in seal contact area REMEDIES 1. 2. 3. 4. 5. 6. 1. 2. 1. 2. 3. 4. 1. 2. 3. 4. Fill as required Replace Replace Align Torque to specs. Torque to specs. Clean and lubricate Repair as required Readjust/tighten Replace Replace Replace Adjust level Replace Tighten Refinish or replace Fig. 7E-9--Transfer Case Diagnosis LIGHT T R U C K SE R V IC E M A N U A L 7E-12 TRANSFER CASE ON VEHICLE SERVICE TRANSFER CASE REPLACEMENT Removal (Fig. 7E-10) 1. Raise and support vehicle on hoist. Drain transfer case. 2. Disconnect speedom eter cable. 3. Rem ove skid p late and crossm em ber supports as necessary. 4. Disconnect rear prop shaft from transfer case and tie up away from work area. 5. Disconnect front prop shaft from transfer case and tie up shaft away from work area. 6. Disconnect shift lever rod from shift rail link. 7. S upport tra n sfe r case and rem ove bolts attach in g transfer case to transm ission adapter. 8. Move transfer case to rear until input shaft clears adapter and lower assembly from vehicle. Installation 1. Support transfer case in suitable stand and position case to transm ission adapter. Install bolts attaching case to adapter and torque to 45 ft. lb. (61 N-m). 2. Remove stand. LIGHT T R U C K SE R V IC E M ANU AL 3. Install connecting rod to shift rail link or connect shift levers to transfer case, as applicable. 4. Connect front prop shaft to transfer case front output flange or yoke. 5. Connect rear prop shaft to transfer case rear output yoke. 6. Install crossm em ber support and skid plate, if removed. 7. Connect speedometer cable. 8. Fill transfer case to proper level with lubricant specified in Section 0-B. 9. Lower and remove vehicle from hoist. Check and tighten all bolts to specified torques. Before connecting prop shafts to companion flanges, be sure locknuts are torqued to specifications. SKID PLATE, STRUT ROD ADAPTER ASSEMBLIES A ttachm ent of the above items is shown in Fig. 7E-10, 11 and 12. R efer to these figures when rem oving or replacing these components. TRANSFER CASE 7E-13 Fig. 7E-10--Transfer Case Attachment-Typical LIGH T T R U C K SE R V IC E M AN U AL 7E-14 TRANSFER CASE A U T O M A T IC Fig. 7E-12--Strut R ods Fig. 7 E -1 1 -S k id Plates Fig. 7 E -13--A d ap ter Assembles LIGH T T R U C K S E R V IC E M AN U AL TRANSFER CASE 7E-15 SPECIFICATIONS N*m MODEL 205 — N«m MODEL 208 26-40 26-40 120-150 120-140 14-20 14-20 2.2-3.2 2.2-3.2 — — 27-34 122-176 BOLT, ADAPTER-TO-TRANSMISSION 26-40 26-40 BOLT, ADAPTER-TO-TRANSFER CASE 26-40 26-40 FILLER PLUG 40-48 40-54 BOLTS P.T.O. COVER 20-24 — NUT, SKID PLATE-TO-CROSSMEMBER 55-70 55-70 40-54 40-54 150-200 150-200 NUT, SHIFT LEVER-TO-SHIFTER ASSEMBLY NUT, KNOB ASSEMBLY-TO-SHIFT LEVER BOLT, SHIFTER ASSEMBLY-TO-TRANSFER CASE NUT, SHIFT ARMS-TO-CASE SCREW, SHIFT LEVER BOOT RETAINER BOLT, DETENT RETAINER SWITCH, INDICATOR 19-27 BOLT, SUPPORT STRUT ROD — TRANSMISSION END — TRANSFER CASE END 205 (PART TIME) 208 (PART TIME) ALL K30 SERIES ALL K10-20 SERIES 1.00 TO 1 1.96 TO 1 2.61 TO 1 LEVER POSITIONS 4-LO (ALL WHEEL UNDERDRIVE) N (NEUTRAL) 2-HI (REAR WHEEL DRIVE) 4-HI (ALL WHEEL DIRECT DRIVE) 4-LO (ALL WHEEL UNDERDRIVE) N (NEUTRAL) 2-HI (REAR WHEEL DRIVE) 4-HI (ALL WHEEL DIRECT DRIVE) LEVER LOCATION REAR OF TRANS. SHIFT LEVER REAR OF TRANS. SHIFT LEVER MODEL NO. AVAILABILITY RATIOS: HI RANGE LO RANGE POWER TAKE-OFF DATA: OPENING AND LOCATION SAE 6-BOLT; LEFT SIDE LUBRICANTS: OIL CAPACITY 5.2 PINTS* 8 PINTS* TYPE, GRADE SEE OWNER’S MANUAL SEE OWNER’S MANUAL *TO BE FILLED WITHIN ONE INCH OF FILL PLUG. LIGHT T R U C K SER V IC E M A N U A L 208--Special Tools SPECIAL TOOLS Fig. 7E-ST1 1. 2. 3. 4. 5. 6. 7. J-29162 J 29170 J-29163 J-29169 J 29168 J-29174 J-29167 — Rear Retainer OIL Seal Installer Input Gear Bearing Remover Ft. Output Shaft Rear Bearing Installer Input Gear Bearing Installer Ft. Output Shaft Ft. Bearing Remover Mainshaft Bearing Installer Ft. Output Shaft Ft. Bearing Installer TRANSFER CASE 7E-17 n 10 1. 2. 3. 4. 5. 6. J —23432 —1 J-23432 J-8092 J-23429 J —22836 J —21359 Snap Ring Picks Snap Ring Pliers Han dl e In te r m e d ia te Sh aft Remover and In s ta lle r Front O u t p u t Shaft Bearing Ret ainer Seal I n s ta l le r Rear O u t p u t Sha ft Be aring Ret aine r Seal In s ta l le r 7. J -23 4 3 1 9. J —713 7 J -9276-2 J —22875 10 . Rear O u t p u t Remover and A d a p t e r Seal In te r m e d ia te Rear O u t p u t Shaft Housing Bearing In s ta l le r I n s ta l le r G e a r Bearing C up In s ta l le r Shaft Rear Bearing I n s ta i le r 1. J-22836 - Front Output Shaft Bearing Retainer Seal Installer J-22388 — Rear Output Shaft Seal Installer J-21359 - Input gear Bearing Retainer Seal Installer J-24745 —Cluster Gear Loading Tool J-8614-1 —Companion Flange Remover 2. 3. 4. 5. Fig. 7E-ST2--205 Special Tools LIG H T T R U C K SE R V IC E M AN U AL ELECTRICAL - BODY AND CHASSIS 8A-1 SECTION 8A ELECTRICAL - BODY AND CHASSIS LIG H TIN G SYSTEM CONTENTS Lighting S y s te m ........................................... ...................... G eneral D escription................................... ................... D iagnosis............................................................................. O n-Vehicle Service.................................... ...................... M ain ten an ce ......................................... ...................... H eadlam p A d ju stm en t............................................. Sealed Beam U n it................................. ...................... Parking Lamp B ulb..................................................... Parking Lamp H ousing ....................... ...................... 8A-1 8A -1 8A-2 8A-9 8A-9 8A-11 8A-11 8A-11 8A-11 Front Side M a rk e r................................................. .... Rear Side M a rk e r .................................................. .... Tail, Stop and Backup L a m p s............................ .... D irectional Signal L a m p s .................................... .... Clearance, License Plate and Ident Lam ps.......... Light S w itc h ................................................................. H eadlam p Beam Selector S w itch ........................... Stoplam p S w itc h ......................................................... Specifications.................................................................. .... 8A-12 8A-12 8A-16 8A-16 8A-16 8A-16 8A-17 8A-17 8A-21 LIG H TIN G SYSTEM GENERAL DESCRIPTION The lighting system includes the main light switch; stop light, dim m er and backing lam p switches; head and parking lamps; stop, tail, side m arker, clearance and identification lam ps; in strum ent illum ination, d irectional signal and indicator lamps and the necessary wiring to complete the various circuits. A bulkhead fuse panel (fig. 8A-1) provides convenient power taps and fuse clips for the appropriate circuits. The engine wiring harness and forward lam p harness connectors are bolted to the fuse panel. All wiring systems not protected by a fuse or circuit breaker incorporate a fusible link which provides increased overload protection. T he sta rtin g m otor circu it is the exception. Composite wiring diagram s are available in Section 8C. The standardized color code is common to all wiring harnesses. The wire covering color designates a particular circuit usage. W ire size designations are m etric, conversions to AW G sizes are provided. LIGHT T R U C K SER V IC E M A N U A L 8A-2 ELECTRICAL - BODY AND CHASSIS Q] 0 0 0 0 0 □ □ 0 0 □ □ 0 0 0 0 0 □ C U IT BREAKER -CHOKE -HEATER OR AIR CONO -AUX HEATER OR AIR CONO -RADIO PTACLE 4C69 •STOP, HAZARD LAMPS PTACLE-POWER ACCESSORY -WINDSHIELD WIPER PTACLE IAU3/A33 -HORN. DOME LAMP PTACLE &T63/UF2/U35 -TAIL, CTSr LAMP PTACLE-IT63 -INSTRUMENT PANEL LAMPS i -TORN, BACK UP LAMPS PTACLE 4K30/LF 9/NL2/HX1/M38/M40/U16 PTACI.f (TJ CIRCUIT B R E A K E R [_Aj FUSE-WINDSHIELD W IP E R | b ] RECEPTACLE-IGN ACC-RADIO & AUX BAT. j C~j FUSE-STOP & TRAF H A ZA R D LPS [d ] P O W E R ACCESSORY [jfj R E C E PT A C L E- PO W ER D OOR LOCK> |_Fj FUSE-INST PA N EL LAM PS [g ] RECEPTACLE-DIR SIG LP F LA SH ER |H| FUSE-HEATER & A./C IT] REC EPTACLE- BAT, L TR , RDO CAP AC. CLOCK, H /L WARNING [ k] RECEPTACLE-PNL LPS, RAD DIAL, TRANS IND LP & TILT WHEEL. [Y] FUSE-HORN D M 1~M| FUSE-DIR SIG & BACK-UP LAM PS m RECEPTACLE-IGN-AUTO TRANS. CRUISE C O N T R O L , PU LSE W IPER , TRANS IND LP [p ] FUSE-GAUGES IqJ FUSE-TAIL LAM PS [R~| R EC EPTACLE- TRAFFIC H A ZA R D F LA SH E R [sl " REC EPTACLE- IGN /AC C REA R AIR C ON D AUX H E A T E R j_Tj FUSE-AUX H E A T E R & A C [u ’| FUSE-RADIO Fig. 8A-1--Fuse Panel LIGHT T R U C K SER V IC E M A N U A L ELECTRICAL - BODY AND CHASSIS 8A-3 D IA G N O S IS HEADLAMP DIAGNOSIS Condition One headlamp inoperative or intermittent Possible Cause 1. Loose connection 2. Defective Sealed Beam One or more headlights are dim. 1. Open ground connection at headlight 2. Black ground wire mislocated in headlight connector (type 2 sealed beam) Correction 1. Secure connections to sealed beam including ground. (Black Wire) 2. Replace sealed beam 1. Repair black wire connection between sealed beam and body ground. 2. Relocate black wire in connector One or more headlights short life 1. Voltage regulator misadjusted 1. Readjust regulator to specifications. All headlights inoperative or intermittent 1. Loose connection 1. Check and secure connections at dim m er switch and light switch. 2. Defective dimmer switch 2. Check voltage at dimmer switch with test lamp. If test lamp bulb lights only at light blue wire terminal, replace dimmer switch. 3. Open wiring - light switch to dimmer switch 3. Check light blue wire with test lamp. If bulb lights at light switch light blue wire terminal but not at dimmer switch, repair open wire. 4. Check red wire terminal at light switch with test lamp. If lamp does not light, repair open red wire circuit to battery, (possible open fusible link) 4. Open wiring - light switch to battery 5. Shorted ground circuit 5. If, after a few minutes operation, headlights flicker “O N ” and “O F F ” and or a thumping noise can be heard from the light switch (circuit breaker opening and closing), repair short to ground in circuit between light switch and headlights. After repairing short, check for headlight flickering after one minute operation. If flickering occurs, the circuit breaker has been damaged and light switch must be replaced. 6. Defective light switch 6. Check red and white wire terminals at light switch with test lamp. If bulb lights at read wire terminal but not at light blue terminal, replace light switch. LIGH T T R U C K SER V IC E M A N U A L 8A-4 ELECTRICAL - BODY AND CHASSIS Upper or lower beam will not light or interm ittent 1. Open connection or defective dimmer switch 1. C heck dim m er switch terminals w ith test lamp. If bulb lights at light blue or tan wire term inals, repair open wiring between dim m er sw itch and headlights. If bulb w ill not light at one o f these term inals, replace dim m er switch. 2. Short circuit to ground 2. F ollow diagnosis above (A ll headlights inoperative or interm ittent) SIDE MARKER LAMP DIAGNOSIS Condition One lamp inoperative Front or rear lam ps inoperative A ll lam ps inoperative LIGHT T R U C K S E R V IC E M A N U A L Possible Cause Correction 1. Turn signal bulb burnt out (Front lamp) 1. Sw itch turn signals on. If signal bulb does not light, replace bulb. (Bulb filam ent provides ground path for marker lam p bulb through the light blue or dark b lu e/w h ite strip wires). 2. Side marker bulb burnt out 2. R eplace bulb. 3. L oose connection or open in wiring 3. U sifig test lam p, check brown wire term inal at bulb socket. If test lam p lights, repair open ground circuit. If lamp does not light, repair open brown wire circuit. 1. L oose connection or open ground connection 1. If associated tail or park lamps do not operate, secure all connectors in brow n wire circuit. If park and turn lam ps operate, repair open ground connections. 2. M ultiple bulbs burnt out 2. R eplace burnt out bulbs. 1. Blow n fuse 1. If park and tail lam ps do not operate, replace blow n fuse. If new fuse blow s, check for short to ground betw een fuse panel and lamps. 2. L oose connection 2. Secure connector to light sw itch. 3. O pen in wiring 3. Check tail light fuse with test lam p. If test lam p lights, repair open w iring between fuse and light sw itch. I f not, repair open wiring betw een fuse and battery. (P ossible open fusible link). ELECTRICAL - BODY AND CHASSIS 4. D efective light sw itch I -1 0*1 U *, lb .? ’ 3 ••?-; 1 U *1 8A-5 4. C h ec k light sw itc h w ith te s t lam p . I f te s t lam p lights a t te rm in a l N o. 5 b u t n o t a t te rm in a l N o. 4 , rep lace light sw itch . TAIL, PARK AND LICENSE LAMP DIAGNOSIS Condition O n e side in o p erativ e B o th sides in o p erativ e Possible Cause Correction 1. B ulb b u rn t o ut 1. R ep la ce bulb 2. O pen g ro u n d con n ectio n a t b u lb socket o r g ro u n d w ire term in al 2. J u m p e r b ulb base socket c o n n e c tio n to g ro u n d . If la m p lights, rep a ir open g ro u n d circu it. 1. T ail lam p fuse blow n 1. R ep lace fuse. I f new fuse blow s, re p a ir sh o rt to g ro u n d in b ro w n w ire circuit betw een fuse panel th ro u g h lig h t sw itch to lam ps. 2. L oose co n n ectio n 2. S ecure c o n n e c to r at light sw itch. 3. O p en w iring 3. U sing test light, check circ u it on b o th sides o f fuse. I f lam p does n o t light on e ith e r side, re p a ir o pen c irc u it betw een fuse panel and b attery , (possible open fusible link). I f test lam p lights at light sw itch b ro w n w ire term in al, re p a ir o pen w iring betw een lig h t sw itch an d lam ps. 4. M u ltip le bulb b u rn o u t 4. I f test la m p lights at lam p so ck et b ro w n w ire term in al, rep lace bulbs. 5. D efective light sw itch If te s t lam p lig h ts a t light sw itc h te rm in a l N o. 4 (B ro w n /w h ite w ire ) b u t n o t a t te rm in a l N o. 5 (B ro w n w ire), rep lac e d efectiv e light sw itc h . LIGH T T R U C K SE R V IC E M A N U A L 8A-6 ELECTRICAL - BODY AND CHASSIS TURN SIGNAL AND HAZARD W ARNING LAMP Condition T u r n signals inoperative one side T u r n signals inoperative Possible Cause Correction 1. Bulb(s) b u rn t out (F la sh e r canno t be he a rd ) 1. T u r n h a z a rd w a rn in g system on. I f one o r m o re b ulbs are inoperative replace necessary bulbs. 2. O p en wiring or gro u n d c o n n e c tio r 2. T u r n H a z a rd w a r n in g sy ste m on. If o n e o r m o re b u lb s are in o p era tiv e , use te st la m p and check circu it at la m p so c k e t. If test lam p lights, r e p a ir o p e n g ro u n d c o n n e c tio n . I f n o t, re p a ir o p e n w iring b e tw e e n bu lb s o c k e t a n d t u r n signal switch. 3. Im p r o p e r bulb or defective turn signal switch. 3. T u r n h a z a rd w a rn in g system on. I f all front a n d rea r lamps operate, check for im p ro per bulb (1034 instead o f 1157). I f bulbs are O K , replace defective tu r n signal switch. 4. Short to ground. (F la sh e r can be heard, no bulbs operate) 4. L ocate an d rep air short to g ro u n d by disconnecting front a n d rear circuits separately. 1. Blown tu rn signal fuse 1. T u r n h a z a rd w a rn in g system on. If all lam ps operate, replace blow n fuse. If new fuse blows, repair sh ort to g ro u n d between fuse an d lamps. 2. Defective flasher (L o c a te d behind in stru m e n t panel near steering colum n) 2. I f tu rn signal fuse is O K and h a z a rd w a rn in g system will operate lam ps, replace defective tu r n signal flasher. 3. Loose connection 3. Secure steering co lu m n connector. I f necessary, check p urple wire term inals in c o n n e c to r with test lamp. If test la m p lights only on one side o f c on necto r, clean o r tighten c o n n e c to r contacts. LIGHT TRUCK SERVICE MANUAL ELECTRICAL - BODY AND CHASSIS H azard warning lamps inoperative 1. Blown stop-hazard fuse 1. Switch turn signals on. If lamps operate, replace stop-hazard fuse if blown. If new fuse blows, repair short to ground. (Could be in stop light circuit). 2. Defective hazard warning flasher. (Located on fuse panel). 2. If stop-hazard fuse is OK, switch turn signals on. If lamps operate, replace defective hazard flasher. 3. Open in wiring or defective turn signal switch. 3. Using test lamp, check brown wire in turn signal steering colum n connector. If lamp does not light on either side of connector, repair open circuit between flasher and connector. If lamp lights only on feed side o f connector, clean connector contacts. If lamp lights on both sides of connector, replace defective turn signal switch assembly. 8A-7 BACK-UP LAMP Condition One lamp inoperative or intermittent Both lamps inoperative or intermittent. Possible Cause Correction 1. Loose or burnt out bulb 1. Secure or replace bulb. 2. Loose connection 2. Tighten connectors. 3. Open ground connections 3. Repair bulb ground circuit. 1. N eutral start switch misadjusted (Open when shift lever is in reverse position) 1. Readjust neutral start switch. 2. Loose connection or open circuit 2. Secure all connectors. If O K , check continuity of circuit from fuse to lamps with test lamp. If lamp does not light on either side of fuse, correct open circuit from battery to fuse. 3. Blown fuse 3. Replace fuse. If new fuse blows, repair short to ground in circuit from fuse through neutral start switch to back-up lamps. Defective neutral start switch 5. Defective ignition switch 4. W ith ignition on, check switch terminals in back-up position with test lamp. If lamp lights at pink wire terminal but not at light green wire terminal, replace neutral start switch. 5. If test lamp lights at ignition switch battery terminal but not at outpu t terminal, replace ignition switch. LIGHT TRUCK SERVICE MANUAL 8A-8 ELECTRICAL - BODY AND CHASSIS L a m p will n o t t u r n off 1. N e u tra l sta rt switch m isadjusted (closed w hen shift lever is not in reverse position) 1 R e a d ju s t n e u tra l sta rt sw itch STOP LIGHTS Condition Possible Cause Correction O ne bulb inoperative 1. Bulb b u rn t out. 1. R eplace bulb. O n e side inoperative 1. Loose connection, open wiring or defective bulbs 1. T u r n o n d ir e c tio n a l signal. If lam p d oes n o t o p e r a t e , check bulbs. If b u lb s are O K , secure all c o n n e c tio n s . I f la m p still d o e s n o t o p e r a te , use test la m p an d ch eck fo r o p e n wiring. 2. Defective directional signal switch or cancelling cam 2. I f lam p will o p e ra te by tu rn in g directional signal on, the switch is not c e n te rin g properly d u rin g cancelling operatio n. Replace defective cancelling cam or directional signal switch. 1. S to p -h az a rd fuse blown 1. R eplace fuse. I f new fuse blows, rep air sh ort to g ro u n d in circuit betw een fuse a n d lamps. 2. S to p -sw itc h m isa d ju sted o r defectiv e 2. W ith b ra k e p e d a l d e p re sse d , ch e c k w h ite wire te r m in a l in steering c o lu m n c o n n e c t o r w ith test lam p. If la m p d o e s n o t light, ch eck s to p sw itc h fo r p ro p e r a d ju s tm e n t . I f a d j u s t m e n t is O K , replace s to p sw itch. 1. Stop switch m isadjusted or defective. 1. R ead ju st switch. I f switch still m alfun ctio ns, replace. All inoperative Will not tu r n off LIGHT TRUCK SERVICE MANUAL ELECTRICAL - BODY AND CHASSIS 8A-9 ON-VEHICLE SERVICE Maintenance of the lighting units and wiring system consists of an occasional check to see that all wiring connections are tight and clean, that the lighting units are securely mounted to provide good ground and that the headlamps are properly adjusted. Loose or corroded connec­ tions may cause a discharged battery, difficult starting, dim lights, and possible damage to the generator. Wire harnesses must be replaced if insulation becomes burned, cracked, or deteriorated. Whenever it is necessary to splice a wire or repair one that is broken, always use solder to bond the splice. Always use rosin flux solder on electrical connections. Use insulating tape to cover all splices or bare wires. When replacing wires, it is important that the correct size be used. Never replace a wire with one of a smaller size. Fusible links in the wiring are four gage sizes smaller than the cable it is designed to protect. The links are marked on the insulation with wire gage size because of the heavy insulation which makes the link appear a heavier gage than it actually is. Each harness and wire must be held securely in place by clips or other holding devices to prevent chafing or wearing away the insulation due to vibration. By referring to the wiring diagram manual, circuits may be tested for continuous circuit or shorts with a conventional test lamp or low reading voltmeter. These wiring diagrams use metric wire size designations, a chart showing metric to A W G size conversions is provided in the manual. The headlam ps must be checked for proper aim whenever a sealed beam unit is replaced and after repairs of the front end sheet metal assembly. Regardless of the method used for checking headlamp aim, the truck must be at normal weight, that is with gas, oil, water and spare tire. Tires must be inflated to specified pressures. Some states have special requirements for headlamp aiming adjustment and these requirements must be known and followed. Horizontal and vertical aiming of each sealed beam is proveded by two adjusting screws visible through the bezel which move the mounting ring against the tension of the coil spring (fig. 8A-2). There is no adjustment for focus since the sealed beam unit is set for focus during manufacturing assembly. HEADLAMP ADJUSTMENT (Fig. 8A-2) The headlam ps must be properly aimed to obtain m axim um road illumination. W hen using mechanical headlamp aimers, follow manufacturers instructions. Fig. 8A-2--Headlamp Adjustments (Typical) LIGHT TRUCK SERVICE MANUAL 8 A -10 ELECTRICAL - BODY AND CHASSIS RADIATOR FRO NT FEN D ER VIEW A RADIATOR SUPPO R T RADIATOR GRILLE LOWER PANEL Fig. 8A-3--Front Lighting (C-K Models) LIGHT TRUCK SERVICE MANUAL FORW ARD LAMP ELECTRICAL - BODY AND CHASSIS 8 A -1 1 FRONT LAMP HARNESS ASSEMBLY FRONT MARKER LAMP VIEW A E94 O R Z80 Fig. 8A-4--Front Lighting (G Models) SEALED BEAM UNIT Replacement (Figs. 8A-3 and 8A-4) 1. Remove bezel retaining screws and bezel. 2. Remove retaining ring. Do not disturb adjusting screw setting. 3. Disconnect wiring harness connector located at rear of unit in engine compartment and remove sealed beam unit. 4. A ttach wiring harness connector to unit. 5. Position new sealed beam unit in mounting ring and install retaining ring. The number molded into lens face must be at top. 6. Install retaining ring then check operation of unit and install bezel. PARKING LAMP BULB Replacement (Figs. 8A-3 and 8A-4) 1. Remove lens retaining screws and remove lens from the housing. 2. Replace bulb and check lamp operation. 3. Install lens and retaining screws. LIGHT TRUCK SERVICE MANUAL 8A -12 ELECTRICAL - BODY AND CHASSIS PARKING LAMP HOUSING Left Side C-K Models Replacement (Fig. 8A-3) 1. Remove parking lamp lens screws and remove the lens. 2. Remove lamp housing retaining screws and pull hous­ ing forward. 3. Disconnect parking lamp wiring harness from housing by rotating bulb socket counterclockwise. 4. Connect wiring harness to new housing by inserting bulb socket into housing and rotating clockwise. 5. Install bulb if removed during disassembly. Install lens and retaining screws. G Models Replacement (Fig. 8A-4) Right Side 1. 2. 3. 4. 5. 6. Remove both headlamp bezels. Remove both parking lamp lens. Remove grille. Remove battery and battery box. Disconnect wiring harness at connector. Remove housing stud nuts and remove housing with pigtail. 7. To install, reverse removal steps. LICENSE LAMP , WIRE ASSEMBLY 1. Remove two screws and parking lamp lens. 2. Disconnect wiring harness at connector. 3. Remove housing stud nuts and remove housing with pigtail. 4. To install, reverse removal steps. FRONT SIDE MARKER LAMP BULB AND/OR HOUSING All Models Replacement For housing replacement follow procedure for the right side bulb replacement below. 1. Left Side - Raise hood. Right Side - Remove lamp assembly retaining screws and pull outward on assembly. 2. Twist wiring harness socket 90° counterclockwise and remove harness and bulb from housing. 3. Replace bulb and check lamp operation. 4. Insert bulb into housing, press in on harness socket and twist 90° clockwise. Check th a t socket is securely attached. 5. Left Side - Lower hood. Right Side - Install housing in opening and install retaining screws. LICENSE LAMP ASSEMBLY DARK GREEN BROW N MARKER LAMP LIGHT GRFEN LIGHT GREEN BROW N LICENSE ' I LAMP WIRE jfc ASSEMBLY & BROW N ( L H SIDE O NLY) Fig. 8A-5--Rear Lighting (G Models) LIGHT TRUCK SERVICE MANUAL FUEL TA NK METER ASSEMBLY RIGHT SIDE ELECTRICAL - BODY AND CHASSIS 8 A -13 Fig. 8A-6--Rear Lighting (C-K Models Except with E56 or E62) LIGHT TRUCK SERVICE MANUAL 8 A -14 ELECTRICAL - BODY AND CHASSIS LICENSE PLATE LAMP WIRE — VIE W 1 FRONT MARKER LAMP HARNESS CENTER MARKER \ X LA M P S WIRE | v ie w ] FRONT WIRE ASSEMBLY TAIL & STOP ~ LAMP ASSEMBLY SIDE MARKER LAMP \ REAR LICENSE ^ LAMP ASSEMBLY ■TAIL & STOP LAMP HARNESS SIDE MARKER LAMP C209 (03) WITH OPTION E56 C310 (03) WITH OPTION E56 Fig. 8A-7--Rear Lighting (C-K Platform and Stake Rack Models) C 3 0 ( 0 3 ) W IT H O P T IO N E56 CK 1 0 - 2 0 A N D C 3 0 9 ( 0 3 ) W IT H O P T IO N E62 Fig. 8AA-8A--Rear Lighting (C30 03 Models with E56 and C-K Models with E62) LIGHT TRUCK SERVICE MANUAL ELECTRICAL - BODY AND CHASSIS 8 A -15 C 3 0 9 W ITH O P T IO N E63 MARKER LAMP ( CREAM) TAIL C O M B IN ATIO N LAMP ( GRAY) 0 3 -6 3 M O D ELS W ITH O P T IO N E63 BACK UP LAMP (WHITE) TAIL C O M BIN ATIO N LAMP (GRAY) MARKER LAMP (CREAM) [ ^ 0 TYPICAL BACK UP LAMP - ''I j £ (WHITE) V ! ^ 0 6 -1 4 M O D ELS 0 3 -6 3 BASE M O DELS Fig. 8A-9--Rear Lighting CK 03 and 43 Models exc E62 or E6E LIGHT TRUCK SERVICE MANUAL 8 A -16 ELECTRICAL - BODY AND CHASSIS REAR SIDE MARKER LAMP BULB DIRECTIONAL SIGNAL LAMPS AND/OR HOUSING Directional signal lamps are an integral part of parking and tail lamp assemblies. Refer to the applicable lamp or bulb replacement procedures covered previously. C-K 03 models with E62 and G Models Replacement Same as Right Front Side Marker Lamp Bulb and/or Housing Replacement - All Vehicles. Bulb on G Models without interior trim may be removed from inside the vehicle. C-K 16, 03 and 63 with E63, and 06 Models CLEARANCE, LICENSE PLATE AND IDENTIFICATION LAMPS Refer to Figures 8 A - 10 and 8 A - 11 for clearance, license plate and identification lamp installations. LIGHT SWITCH Replacement 1. Remove lens to housing four screws. 2. Replace bulb and check operation. 3. Position lens and install four attaching screws. Platform and Stake Rack Models (E56) Exploded view of the different rear lighting arrange­ ments are shown in Figures 8A-7 and 8A-8. The bulbs may be replaced by removing the lamp lens attaching screws and lamp lens. The lamp housings may be replaced by removing housing attaching nuts or screws, or by removing nuts and bolts from bracket. TAIL, STOP AND BACKUP LAMP BULBS Replacement 1. Remove lens to housing attaching screws. 2. Replace bulb and check operation. 3. Position lens and install attaching screws. TAIL, STOP AND BACKUP LAMP HOUSING C-K 16, 03 and 63 w /E 63 and 06 Models All G Models Replacement 1. 2. 3. 4. Remove lens to housing attaching screws. Remove bulbs from sockets. Remove housing attaching screws (nuts on G Models). Rotate wiring harness sockets counterclockwise and remove housing. 5. To install, reverse Steps 1-4 above. LIGHT TRUCK SERVICE MANUAL C-K Series (Fig. 8A-12) Replacement ^OST'vO HTIW . | 1. Disconnect battery ground cable. 2. Reaching up behind instrument cluster, depress shaft retaining button and remove switch knob and rod. 3. Remove instrument cluster bezel screws on left end. Pull out on bezel and hold switch nut with a wrench. 4. Disconnect multiple wiring connectors at switch terminals. 5. Remove switch by rotating while holding switch nut. 6. To install; reverse Steps 1-5 above. V-:-’ i G Series (Fig. 8A -12) Replacement 1. Disconnect battery ground cable. 2. Reaching up behind instrument panel, depress shaft retaining button and remove switch knob-shaft. 3. From front of instrument panel remove switch retain­ ing nut. 4. Push switch from panel opening and remove multiple electrical connector at switch terminals. 5. To install, reverse Steps 1-4, making sure grounding ring is installed on switch. ELECTRICAL - BODY AND CHASSIS 8A -17 Fig. 8A-12—Light and Headlamp Beam Selector Switches HEADLAMP BEAM SELECTOR SWITCH STOPLAMP SWITCH Replacement See Section 5 (Brakes) of this manual for adjustment and replacement procedures. 1. Fold back upper left corner of the floor mat and remove two screws retaining switch to the floor pan. 2. Disconnect wiring connector from switch terminals. 3. Connect wiring to replacem ent switch and check operation. 4. Position switch to floor pan and install retaining screws. 5. Replace floor mat. LIGHT TRUCK SERVICE MANUAL 8 A -18 ELECTRICAL - BODY AND CHASSIS PARKING BRAKE BRACKET FRONT MARKER LAMP FRO NT LAMP 4 $* BRAKE DIST. & SW. ASSEMBLY HORN A SSEM BLY ENGINE HARNESS HORN ASSEMBLY NUT BATTERY GROUND PARKING BRAKE CABLE VIEW C VIEW B PARKING BRAKE NUT VIEW D Fig. 8A-13--G Series Forward Lamp W iring FUSE PANEL REINFORCEMENT GROUND WIRE GROUND WIRE SIDE MARKER LAMP PARKING LAMP BRACKET DIST & SWITCH .RADIATOR GRILLE PANEL FRAME (2B) Fig. 8A-14--CK Series Forward Lamp Wiring LIGHT TRUCK SERVICE MANUAL ELECTRICAL - BODY AND CHASSIS 8 A -19 VIEW B VIEW A CR O SSM EM BER 2-9.00 Fig. 8A-15--CK Series Rear Lamp Wiring LIGHT TRUCK SERVICE MANUAL 8A -20 ELECTRICAL - BODY AND CHASSIS LIGHT TRUCK SERVICE MANUAL ELECTRICAL - BODY AND CHASSIS 8 A -2 1 S P E C IF IC A T IO N S LAMP BULB DATA C-K-P TRUCK USED IN Q UANTITY Dome Lamps: Cab U tility & Suburban Oil Pressure indicator lamp1 Generator indicator lamp1 Instrument cluster lamps2 Headlamp beam indicator lamp Lamp assembly - tail & stop lamp License Lamp4 Directional signal (front park lamps)6 Head Lamps Temperature indicator lamp Directional signal indicator lamp Clearance and marker lamps Roof marker lamps5 Brake warning indicator Transmission control (auto) Backing lamp (exc. motor home) Backing lamp (motor home) Heater or A/C Corner marker lamps (platform) Cargo lamp (C-K cab) Radio dial lamp - AM - AM/FM Courtesy lamp Windshield wiper switch Clock Rear identification7 Underhood lamp Seat belt warning Cargo/dome lamp Four wheel drive indicator Choke heater Ind LAMP BULB DATA G TRUCK TRADE # POWER 1 1 1 1 5 1004 211-2 168 168 168 1 168 3 CP 2 1 1157 67 3-32 CP 4 CP 2 2 1 1157 6014 168 3-32 CP 50-60 W 3 CP 2 4 5 1 1 168 168 194 168 1445 3 CP 3 CP 2 CP 3 CP 0.7 CP 2 2 1 1156 1295 161 32 CP 50 CP 1 CP 7 1 1 1 1 1 1 10 1 1 2 1 1 67 1142 1816 216 1003 161 168 1895 93 168 211-2 161 168 4 CP 21 CP 3 CP 1 CP 15 CP 1 CP 3 CP 2 CP 15 CP 3 CP 12 CP 1 CP 3 CP 15 12 3 3 3 CP CP CP CP CP USED IN Dome lamps Oil pressure indicator lamp Generator indicator lamp Instrument cluster lamps11 Headlamp beam indicator lamp Park, directional signal lamps Tail, stop lamps License lamp Head lamps12 Temperature indicator lamp Directional signal indicator lamp Marker lamps Brake warning indicator lamp Back-up lamp Radio dial lamp Heater or A/C control Transmission control w /tilt wheel W/S wiper switch lamp Transmission control Choke heater ind Seat belt warning Instrument cluster lamps9 Instrument cluster lamps10 9 10 11 12 QUANTITY TRADE# POWER 2 1 1 1 211-2 161 194 161 1 161 1 CP 2 2 1 2 1 1157 1157 67 6014 194 3-32 CP 3-32 CP 4 CP 50-60 W 2 CP 2 4 1 2 1 1 194 168 194 1156 1893 194 2 CP 3 CP 2 CP 32 CP 2 CP 2 CP 1 1 1 1445 161 73 1893 194 194 168 0.7 CP 1 CP .3 CP 2 CP 2 CP 2 CP 3 CP 1 1 5 1 12 CP 1 CP 2 CP 1 CP 'G ' model w/o gauges; 1 lamp with gauges 'G' model w/o gauges; 3 lamps with gauges *G' model with gauges only Double filament sealed beam 60W high beam, 50W low beam. 1 On CA, KA 10-35 instrument clusters only. 2 3 lamps used on instrument cluster on P models or C-K w/o gauges. 3 Double filament sealed beam 60W high beam, 50W low beam. 4 2 lamps used with step bumper and P models. 5 4 required on P models. 6 1157 NA, 2.2-24 CP on C-K models. 7 Wideside Pickup. 8 P' truck only. LIGHT TRUCK SERVICE MANUAL ■J' ■:-r ..IT!a •'’ '' 'r ■ r ': : ELECTRICAL AND W IRING 8B-1 SECTION 8B ELECTRICAL AND WIRING CONTENTS Radio R e c e iv e r................................................................ Speakers............................................................................ Circuit Protection............................................................. General Description....................................................... Circuit B reak er............................................................. F u s e ................................................................................. Fusible L in k .................................................................. 8B-1 8B-3 8B-4 8B-4 8B-4 8B-5 8B-5 Diagnosis.......................................................................... 8B-5 On-Vehicle Serv ice........................................................ 8B-6 Headlamp Warning Buzzer........................................... 8B-6 Seat Belt Warning S y s te m ............................................ 8B-6 Anti-Theft Alarm S ystem .............................................. 8B-8 Specifications.....................................................................8B-12 RADIO RECEIVER 3. AM Radio -Remove the radio support bracket stud nut and lockwasher. REMOVAL AND INSTALLATION A M /F M Radio -Remove radio support bracket to instrument panel screws. C-K Series Replacement (Fig. 8B-1) 1. Disconnect battery ground cable. 2. Pull off radio control knobs and remove knob bezels. Remove nuts and washers from control shafts using a deep well socket. 4. Lift up on the rear edge of radio. Then push radio forward until control shafts clear instrument panel. Lower control far enough to disconnect electrical harness. 5. Disconnect power feed, speaker and antenna lead wires and remove radio. Fig. 8B-1--Radio Receiver (C-K Series) LIGHT TRUCK SERVICE MANUAL 8B-2 ELECTRICAL AND WIRING 6. To install, reverse Steps 1-5 above. Replacement (All Models) AM Radio G Models 1. Slide radio dial lens upward, approximately 1/8 inch. Replacement (Fig. 8B-2) 2. Tip bottom edge of lens outward (toward technician) and remove lens. 1 Disconnect battery ground cable. 3. Pull out bulb section and remove bulb. 2. Remove engine cover. 3. Remove air cleaner cover and element. 4. Remove radio control knobs and retaining nuts. 5. Remove rear mounting bracket. 6. Push radio forward in vehicle and then lower assembly and disconnect electrical harnesses and antenna lead. 7. Remove radio receiver from vehicle. 8. To install, reverse Steps 1-7 above. 9. Check operation. CAUTION:Always attach speaker wiring harness before applying power to the radio to prevent receiver damage. RADIO DIAL BULB 4. Install new bulb into socket and then reinstall bulb section. 5. Reinstall dial lens. AM-FM And Stero Radio 1. Slide radio dial lens upward approximately 1/8 inch. 2. Tip bottom edge of lens outward (toward technician) and remove lens. 3. Remove rear dial plate screw. Place dial pointer at 16 and remove plate. 4. Remove bulb. 5. To install, reverse steps 1-4 above. Tape Player Radio AM and A M /F M radio dial bulbs can be replaced with the radio in the truck. Tape player radios must be removed from the vehicle for dial bulb replacement. It is not recommended that CB Radio dial bulb be replaced except by a qualified radio repair service. 1. Remove radio from vehicle. 2. Remove radio top cover. 3. Remove bulb. 4. To install, reverse steps 1-3 above. Fig. 8B-2--Radio Receiver lnstallation--G Models LIGHT TRUCK SERVICE MANUAL ELECTRICAL AND W IRING 8B-3 3. Remove instrument cluster. 4. Remove speaker attaching screws, disconnect wiring harness and remove speaker. 5. To install, reverse Steps 1-4 above. 6. Check operation. C Models—Right Side AM /FM Fig. 8 B -3 --R a d io Front S p e a k e r (C -K Series) 1. Disconnect battery ground cable. 2. Remove engine cover. 3. Remove steering column brace bolts. 4. Remove radio support bracket bolt and instrument panel upper and lower attaching screws. 5. Pull instrument panel assembly rearward to gain access to speaker. 6. Remove speaker attaching screws, disconnect speaker wiring harness and remove speaker. 7. To install, reverse Steps 1-6 above. 8. Check operation. REAR SPEAKER FRONT SPEAKER C-K Series C-K Models Replacement (Fig. 8B-5) Replacement (Fig. 8B-3) 1. 2. 3. 4. 5. Disconnect battery ground cable. Remove instrument cluster bezel upper four screws. Remove instrument panel pad screws and remove pad. Remove speaker to dash panel screws. Lift up on speaker, disconnect speaker wiring harness and then remove speaker. 6. To install, reverse Steps 1-5 above. 1. Remove four screws securing speaker grille to trim panel and remove grille. 2. Disconnect electrical connector from speaker. 3. Remove two screws securing speaker to trim panel and remove speaker. On 109 and 209 (06) models, there is a gasket between speaker and trim panel. 4. Install replacement speaker in reverse order of removal. G Models G Models Replacement (Figs. 8B-6 and 8B-7) Replacement (Fig. 8B-4) G Models—Left Side 1. Disconnect battery ground cable. 2. R em o ve instrum en t panel b ezel. 1. Remove the four most forward lower screws securing right rear trim panel. Pull trim panel outward slightly for access to speaker. 2. Disconnect electrical connector from speaker. 3. Remove four nuts securing speaker to grille studs and remove speaker. 4. Install replacement speaker in reverse order of removal. CK 1 0 5 (0 0 ) & Z 8 4 .0 9 + 2 0 9 (0 6 ) Fig. 8B-4--Speaker lnstallation--G Series Fig. 8B-5--Rear Speaker (C-K Models) LIGHT TRUCK SERVICE MANUAL 8B-4 ELECTRICAL AND W IRING REINFORCEMENT SPEAKER SPEAKER GRILLE [v ie w [ a 1 SPEAKER Fig. 8B -7 --R e a r S p e a k e r (G (0 6 ) Truck) Fig. 8 B -6 --R e a r S p e a k e r (G (0 5 ) Truck) CIRCUIT PROTECTION GENERAL DESCRIPTION All electrical circuits are protected against excessive loads which might occur due to shorts or overloads in the wiring system. Such protection is provided by either a circuit breaker, fuse or fusible link. Each of these protective devices are explained below. LIGHT TRUCK SERVICE MANUAL CIRCUIT BREAKER (Fiq 8B-8) . . A circuit breaker is a protective device designed to open circu^ when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excess current willl open the circuit breaker and cause it to cycle if it automatically resets, thus, indicating there is something wrong in the ELECTRICAL AND WIRING BREAKER 8B-5 TO JUNCTION BLOCK CON NEC TOR C O V E R IN G FU SIBLE LIN K BEFORE SHORT C IR C U IT CUT WIRE HERE FU SIB LE L IN K AFTER SHORT C IR C U IT Fig. 8B-9-Fusible Link Fig. 8B-8--Fuse and Circuit Breaker system. The circuit breaker will continue to cycle until the trouble is found and corrected. Excessive cycling of the breaker will eventually damage the breaker contacts to the point that replacement of the breaker is necessary. 2. A 16 gage red fusible link is located at junction block to protect all unfused wiring of 12 gage or larger. The link is molded into the bulkhead connector. 3. The generator warning light and field circuitry (16 gage wire) is protected by a fusible link (20 gage red wire) used in the " battery feed to voltage regulator # 3 term in al". The link is installed as a molded splice in the circuit at the junction block. Service by splicing in a new 20 gage wire. DIAGNOSIS FUSE (Fig. 8B-8) A common method of protection is to use a fuse in the circuit. Whenever there is an excessive current through the circuit, the fusible element will melt and open the circuit. The disadvantage of using a fuse instead of a circuit breaker is the fuse in a one-time protection and replacement is required. FUSIBLE LINK (FIG. 8B-9) In addition to circuit breakers and fuses, the wiring harness incorporates fusible links to protect the wiring. Links are used rather than a fuse in wiring circuits that are not normally fused, such as the ignition circuit. Fusible links are color coded red in the charging and load circuits to match color coding of the circuit they protect. Each link is four gage sizes smaller than the cable it is designed to protect and are marked on the insulation with wire gage size because the heavy insulation makes the link appear a heavier gage than it actually is. Engine com partm ent wiring harnesses incorporate several fusible links. The same size wire with special hypalon insulation must be used when replacing a fusible link. The links are: 1. A molded splice at the starter solenoid " B a t" terminal, 14 gage red wire. Servicing requires splicing in a new link. Failures in a circuit are usually caused by short or open circuits. Open circuits are usually caused by breaks in the wiring, faulty connections or mechanical failure in a component such as a switch or curcuit breaker. Short circuits are usually caused by wires from different compo­ nents of the circuit contacting one anothe or by a wire or component grounding to the metal of the body due to a screw driven through the wires, insulation cut through by a sharp metal edge, etc. The following information may aid in locating and correcting a failure in the body wiring electrical system. 1. If a major portion of the electrical circuit becomes inoperative simultaneously, the failure may be due to im proper connections between the front and rear harness, or between the front harness and the chassis wiring connector on top of fuse block. 2. If only one of the circuits is inoperative, the failure is due to and open circuit or short in the affected circuit. Short circuits usually result in blown fuses or in the case of power equipment circuits, in the circuit breaker opening the circuit. If the fuse is not blown and the circuit affected is a lamp circuit, check the bulb before proceeding with any checking procedures. 3. The dome lamp and courtesy lamp circuits are designed so that the switches are in the "ground" side of the circuit. If a condition is encountered where the lamps remain "on" even though the jam b or courtesy lamp switches are not actuated, the failure is probably due to defective switches, or to the wire leading to the switches being grounded to the metal body. LIGHT TRIJCK SERVICE MANUAL 8B-6 ELECTRICAL AND WIRING ON-VEHICLE SERVICE HEADLAMPS WARNING BUZZER Fusible Link R eplacem ent (Fig. 8B -10) R eplacem ent (Fig. 8 B -1 1) A new fusible link can be installed, after the short circuit is located and repaired, as follows: 1. Disconnect battery ground cable. 2. Disconnect fusible link from junction block or starter solenoid. 3. C ut harness directly behind connector to remove damaged fusible link (fig. 8B-9). 4. Strip harness wire approximately 1/2". 5. Position clip around new fusible link and harness wire, crimp so that all wires are securely fastened. 6. Solder connection using rosin core solder. Use sufficient heat to obtain a good solder joint. 7. Tape all exposed wires with plastic electrical tape to prevent corrosion and shorting. 8. Connect fusible link to junction block or starter solenoid. 9. Connect battery ground cable. CONNECTOR F U SIB LE LIN K THOROUGHLY TAPE ALL EXP O SED W IR E S CONNECTOR C R IM P E D AND SOLDERED Fig. 8B-10--Fusible Link Replacement Fig. 8B-1 T-Healdamp Warning Buzzer LIGHT TRUCK SERVICE MANUAL 1. Disconnect electrical connector from LPS (Lam ps) socket of fuse panel. 2. Disconnect electrical connector from IGN (Ignition) socket of fuse panel. 3. Disconnect electrical connector to instrument panel harness. 4. Remove strap securing buzzer to instrum ent panel harness. 5. Install replacement headlamp warning buzzer in re­ verse wequence of removal. SEAT BELT WARNING SYSTEM All C-K type light duty trucks have a non-sequential timer controlled seat belt warning system. This system has an instrument panel warning light that will illuminate every time the ignition switch is turned on, whether or not the driver’s seat belt is buckled, but will automatically go off after 4-8 seconds. The buzzer is also controlled by the 4-8 second timer, but will operate only if the driver has not buckled-up prior to turning on the ignition. If no attem pt is made to buckle-up after turning on the ignition, the buzzer will also shut-off automatically after 4-8 seconds. A trouble shooting diagnostic chart and wiring sche­ matic are shown in Figures 8B-12 and 8B-13. SEAT BELT REMINDER LIGHT/BUZZER DIAGNOSIS Fig. 8B-12--Seat Belt Reminder System Diagnosis ELECTRICAL AND WIRING 8B-7 8B-8 ELECTRICAL AND WIRING Fig. 8B-13--Seat Belt Reminder System Schematic ANTI-THEFT ALARM SYSTEM - G SERIES COMPONENTS AND LOCATIONS Protective switches are located at each of the forward doors, at the side door lock pillar, at the right hand rear door hinge pillar, and at the hood. The anti-theft relays and flasher are located underneath the instrument panel at the left side of the vehicle near the parking brake mechanism. The anti-theft warning horn is mounted to the fender inner support just forward of the battery tray at the right side of the vehicle. The fender mounted arming switch is protected by an anti-tamper switch which will sound the alarm if an attem pt is made to forcibly remove the lock or cylinder. See Figures 8B-15 thru 8B-18. OPERATION (SEE FIGURE 8B-14) With the system (key) switch in the off position and all protective switches open no ground path exists for the coil of Relay A, or Relay B. When the driver leaves the vehicle, closes the doors (opening the protective switches) and turns the arming switch clockwise to a closed position, the system is then armed. The closing of any of the protective switches will then complete a path to ground for the Relay coil A. The plus terminal of this coil is hot ( 12V) at all times. LIGHT TRUCK SERVICE MANUAL Thus energized, the relay coil closes the relay contacts, providing a path to ground for Relay B (plus terminal of coil is hot (12V) at all times). At the same instant the closed contacts of Relay A provide a ground path through the key switch to terminal 3 of Relay A. Terminal ( # 3) was initially grounded by the closing of a protective switch; however, if the door were closed, the alarm would stop. To ensure th at the alarm continues to sound, a holding action is provided by the Diode, D l. As long as this path to ground is unbroken, the relay remains energized. Closing the door will not break this path to ground as illustrated in the diagram. As terminal 3 of Relay B is grounded, the relay pulls in closing the contacts and completing the flasher/horn circuit to + 1 2 volts. The flasher then opens and closes pulsating the anti-theft horn, which process continues until the alarm is disarmed with the key switch, or the battery is exhausted. The wiring diagram Figure 8B-14 shows another switch at terminal 3 of Relay B. This is the anti-tamper switch, which closes if an attem pt is made to remove or force the lock, regardless of whether the alarm has been set or not. When the switch closes, a ground path is provided for terminal # 3 of Relay B and the alarm sounds. The other protective switches, the key switch, and Relay A not ELECTRICAL AND W IRING involved in this actuation of the alarm, and the key switch will not stop the alarm. To stop the alarm, the plunger of the anti-tamper switch must be depressed, or power removed from the system (Relay B disconnected). 8B-9 Component attachm ent and locations are illustrated in Figures 8B-15 thru 8B-18. LIGHT TRUCK SERVICE MANUAL 8B -10 ELECTRICAL AND W IRING LIGHT TRUCK SERVICE MANUAL ELECTRICAL AND W IRING 8B-11 LIGHT TRUCK SERVICE MANUAL 8B-12 ELECTRICAL AND WIRING SPECIFICATIONS FUSES — CIRCUIT BREAKERS The wiring circuits are protected from short circuits by a combi­ nation of fuses, circuit breakers, and fusible thermal links in the wiring itself. This g reatly reduces the hazard of electrically caused fires in the vehicles. Idle Stop Solenoid, Cruise C o n tro lt, Directional Signal Lamp, Time Delay Relay, Emission Control Solenoid, Transmission Downshift ( M 4 0 ) ........................... The headlam p circuits are protected by a circuit breaker in the light switch. An electrical overload on the breaker will cause the lamps to go on and off, or in some cases to remain off. In-line fuses are located in the au xilia ry heater circuits (C-K-P models) and underhood lamp, front and rear A/C circuits (C-K models) 10 Amp tW h e n incorporated by body builder In addition to a fuse, the windshield w iper motor is also pro­ tected by a circuit breaker. If the motor overheats, due to overloading caused by heavy snow, etc., the wipers will remain stopped until the motor cools. Fuses located in the Junction Block beneath the dash on the drivers side are: Do not use fuses of higher amperage than those recommended above The following wiring harnesses are protected by a "fusible link" which is a special wire incorporated in the circuit headlamp hi-beam indicator, horn, air conditioning high blower, ignition circuits (C-K-P models) starter solenoid (pull-in and hold) circuit(C-K models). Should an electrical overload occur, this wire will fail and prevent damage to the major harness. G TRUCK C-K TRUCK Heater, Front A/C, G enerator W arning Lam p ........................................................................... Idle Stop Solenoid, Aux. Battery, Radio, Time D elay Relay, Emission Control Solenoid, Transmission Downshift ( M 4 0 ) .......................... Cigarette Lighter, Clock, Dome Lamp, Cargo L a m p ............................................................ Fuel G au g e , Brake W arning Lamp, Temperature W arning Lamp, O il Pressure W arn ing Lamp .................................... Courtesy Lamp, Roof M arker Lamp, License Plate Lamp, Parking Lamp, Side M arker Lamp, Tail Lamp, Clearance Lamp .................................................. Directional Signal Indicator Lamp, Stop Lamp, Traffic H a z a r d ....................................................... Instrument Cluster Lamp, H eater Dial Lamp, Radio Dial Lamp, Cruise Control Lamp, W indshield W ip e r Switch L a m p ...................... W indshield W ip e r /W a s h e r .................................... Cruise Control, Rear W indow Aux., Fuel Tank, Tachometer, Back-up Lamp, Directional Signal Indicator Lamp, Directional Signal Lamp, H ead lam p Buzzer ........................ 20 Amp 15 Amp 20 Amp 4 Amp 20 Amp 15 Amp 4 Amp 25 Amp H eater, A / C ................................................................. Idle Stop Solenoid, Cruise Control, Directional Signal Lamp, Directional Signal Indicator Lamp, Transmission Downshift ( M - 4 0 ) ................................................... C igarette Lighter, Dome Lamp, Spot Lamp . . . Fuel G au ge, Brake W arning Lamp, Temperature W arning Lamp, G enerator W arning Lamp, O il Pressure W arning Lamp Stop Lamp, Traffic H a z a r d .................................... A uxiliary Battery, Backing Lamp, Radio Dial Lamp, Radio ................................................ Instrument Cluster Lamp, H eater Dial Lamp, Transmission Control Lamp with Tilt W h e el, Cruise Control Lamp, W /S W ip e r Switch Lamp, H ead lam p B u z z e r...................... License Lamp, Parking Lamp, Sid e M arker Lamp, Tail L a m p .................................... W indshield W i p e r ..................................................... 25 Amp 10 Amp 15 Amp 3 Amp 15 Amp 15 Amp 3 Amp 15 Amp 25 Amp An in-line fuse is located in the Ammeter and the auxiliary heater circuits. Do not use fuses of higher amperage rating than those recommended above 15 Amp The following wiring harnesses are protected by a "fusible link" which is a special wire incorporated in the circuit, ignition, horn and headlamp hi-beam indicator circuits, air conditioning high blower. Should an electrical overload occur, this wire will fail and prevent damage to the major harness. P TRUCK H e a te rt, A ir C o n d it io n in g t.................................. Instrument Cluster Lamp, W indshield W ip er Switch L a m p .............................................. Directional Signal Indicator Lamp, Stop Lamp, Traffic H a z a r d ....................................................... Fuel G au g e , Brake W arn ing L a m p ................... License Plate Lamp, Parking Lamp, Side M arker Lamp, Tail Lamp, C learance Lamp, Identification L a m p .......... W indshield W a s h e r /W ip e r .................................... C ig arette Lighter!, C lo ckt, Courtesyt, Dome Lampt .......................................................... A uxiliary Batteryf, Back-up Lamp, R a d i o ........................................................................ LIGHT TRUCK SERVICE MANUAL 25 Amp CIRCUIT BREAKERS 3 Amp 15 Amp 3 Amp 15 Amp 25 Amp 15 Amp 15 Amp DEVICE OR CIRCUIT PROTECTED MODELS AMPERES LOCATION C-K-P-G 15 Light switch T ailg ate window motor C-K 30 Dash (forward side) Rear A/C (C69 overhead) G 35 Dash (forward side) H eadlam p and .parking lamp circuit INSTRUMENT PANEL AND GAGES 8C-1 SECTION 8C INSTRUMENT PANEL AND GAGES CONTENTS Instrument Panel and G ages........................................... General Description......................................................... Diagnosis............................................................................ On-Vehicle Service.......................................................... Component Part Replacem ent................................... N eutral Start Sw itch.................................................. Backing Lamp S w itc h ................................................ Windshield W iper/W iper/W asher S w itc h ........... Ignition S w itc h ............................................................ Instrument C lu s te r...................................................... Indicator and Illuminating Bulbs............................. Laminated (Printed) C irc u it.................................... S p ee d o m e te r................................................................. Speedometer Cable C o re ........................................... Fuel G a u g e ................................................................... Temperature G a u g e .................................................... Temperature Sending U n i t ...................................... Oil Pressure G auge...................................................... Oil Pressure Sending U n i t ........................................ V oltm eter...................................................................... Directional Signal S w itc h ......................................... Instrument Panel Wiring Harnesses.............................. 8C-1 8C-1 8C-2 8C-7 8C-7 8C-7 8C-7 8C-7 8C-7 8C-10 8C-10 8C-11 8C-11 8C-11 8C-11 8C-11 8C-12 8C-12 8C-15 8C-15 8C-I5 8C-15 Windshield Wiper and W asher (C-K and G Models) General Description......................................................... Electrical Circuits.......................................................... Diagnosis............................................................................. Wiper - On V ehicle....................................................... Wiper - Off Vehicle....................................................... On Vehicle Service.......................................................... Component Part Replacem ent................................... Wiper M o to r................................................................. Unit R epair........................................................................ W iper/W asher Disassembly........................................ Motor Disassembly........................................................ Motor A ssem bly............................................................ Wiper A d ju s tm e n ts ....................................................... Washer P u m p ................................................................. Windshield Wiper and Washer (P M odels)................ General Description......................................................... Diagnosis............................................................................ Wiper - On Vehicle....................................................... Unit Repair.......................... ............................................. Wiper M o to r................................................................... Windshield W a s h e r....................................................... Wiring D i a g r a m s ............................................................. .8C-18 8C-18 8C-18 8C-21 8C-21 8C-21 8C-32 8C-32 8C-32 8C-32 8C-32 8C-32 8C-32 8C-33 8C-33 8C-38 8C-38 8C-40 8C-40 8C-45 8C-45 8C-46 8C-56 GENERAL DESCRIPTION All instruments and gages are installed in the instru­ ment cluster. Instruments and gages can be serviced in the vehicle (C-K Series); however, the entire cluster must be removed from the vehicle for servicing of the instruments and gages (G Series). Illuminating and indicator lamps may be replaced without removing the cluster from the vehicle. Bulbs are installed in plastic holders which lock into the cluster housing. Regular maintenance is not required on the instrument cluster or its components other than maintaining clean, tight electrical connections, replacing defective parts and keeping the speedometer cable properly lubricated. 8C-2 INSTRUMENT PANEL AND GAGES D IA G N O S IS OIL PRESSURE INDICATOR Condition L ight not lit, ignition on and engine not running. Possible Cause Correction 1. Bulb bu rn e d out. 1. R ep lace bulb. 2. O pen in light circuit. 2. Locate a n d co rre c t open. 3. D efective oil pressure 3. R ep lace oil p re ssu re switch. switch. L ight on, engine ru n n in g above idle speed. 1. G r o u n d e d wiring between light an d switch. 1. L o cate a n d re p a ir ground. 2. D efective oil pressure 2. R e p la ce oil p re ssu re switch. switch. 3. Low oil pressure. 3. L o c a te cause o f low oil pressure a n d correct. COOLANT TEMPERATURE INDICATOR Condition “ H O T ” indicator; light not lit w hen c ra n k in g engine. Possible Cause Correction 1. Bulb b u rn e d out. 1. R e p la c e bulb. 2. O pen in light circuit. 2. L o cate a n d c o rre c t open. 3. D efective ignition 3. R e p la c e ignition switch. switch. L ight on, engine running. U ;HT TRUCK $ awi Check the following: 1) Pawl spring properly connected. 2) Cam-follower not binding. STEP 5 Moves back and forth Leave wiper running and Go To STEP 5 Connect 12(+) volts to one of washer pump terminals (6 or 7) and ground the other for approx. 2 seconds. Observe it relay armature is pulled toward the relay coil; armature leg drops down on gear ramp and ratchet pawl starts rotating ratchet gear. Refer to view in STEP 4. Operates OK Go To STEP 6 Relay armature operates correctly but ratchet gear doesn’t rotate. Check ratchet gear teeth and/or ratchet gear dog spring engages gear teeth. Refer to above Illustration. Armature Leg doesn’t clear rim on ratchet gear. Drops back in slot area on edge of rim. Check the following: a) Relay coil-sw. assy, correctly assembled to washer frame b) Burr on end of armature leg. File off as required. c) Loose coil on pole piece. STEP 6 Replace valve assembly and recheck pump. If washer pump still fails to pump solution, replace piston and housing assembly. LIGHT TRUCK SERVICE MANUAL Replace piston and housing assembly, INSTRUMENT PANEL AND GAGES 8C-29 PROCEDURE 10 (Washer Pumps Continuously) Have wiper running and disconnect wiring from washer pump terminals 6 and 7. Observe if pump completes wash cycle and stops pumping. Pump keeps running Pump stops Check for grounded wire between pump terminal and dash switch or a defective dash sw. Go To STEP 2 Disconnect wiring from wiper unit; remove washer pump cover and re-connect w iring to wiper-washer. Turn on wiper and check the follow ing items.__________ a) b) c) d) Ratchet gear dog spring engaging ratchet gear teeth. Weak spring tooth on ratchet gear. Ratchet gear tooth damaged Cam-follower damaged. Replace item(s) as required. LIGHT TRUCK SERVICE MANUAL 8C-30 INSTRUMENT PANEL AND GAGES DELAY WIPER SYSTEM OPERATION AND DIAGNOSIS Light duty trucks use a separate control assembly to operate the windshield wipers over a variable delay of 1 to 20 seconds. The control assembly plugs into the selector switch at two different connectors. One of these connectors has a piggy-back connector that connects to the regular wiper harness. There is also a lead from the control that plugs into the accessory cavity of the fuse panel. Moving the control knob of the selector switch to the extreme left position and holding it there, will result in a M IST mode. The mist mode feature provides momentary low speed wiper operation as long as the control knob is held in position. This position is spring loaded and will only remain activated as long as the knob is held in position. Upon releasing the control knob, it will automatically return to O F F position. By positioning the control knob in the first detent right of OFF, the selector switch is in the D E LA Y mode. Rotation of the control knob while in the delay mode regulates the delay period between the time it takes the wiper to make one sweep and momentarily stop. Shifting the control knob right to next detent -position will put the wipers in a LOW speed wiper mode. By moving the control again to the right (right most detent) will activate the H IG H speed wiper mode. Depressing the control knob, in any mode, will result in washer fluid being squirted on the windshield. Depressing the control knob on light duty trucks for one or two seconds will send a measured amount of fluid onto the windshield and then the washer will shut off. If the wiper control knob is any position other than H IG H , the wipers LIGHT TRUCK SERVICE MANUAL will continue to operate at low speed until they are manually turned OFF. In the H IG H mode, depressing the knob results in washer fluid being dispensed with the wipers operating at the high speed mode. Selector Switch Checking Procedure If the wiper washer selector switch is suspected of being faulty, it can be checked with an ohmeter as indicated in C hart 8-16. Before performing any continuity check discon­ nect both harness connectors from switch to controller. N ext, place selector switch in mode desired and perform a continuity check between the individual leads as indicated in the chart. If there is a meter reading at each check but no indication of shorts, the switch can be assumed to be good. INSTRUMENT PANEL AND GAGES 8C-31 ------- HG' W‘. 531 riJ 'J.'tXty:. >b fOJC- ri ' 'v.j" "•(•'jd i.. 7 K i n '3 ’V.;jq W IP E R S DO NOT DELAY icifeni 6 • !J- / . I T 1 0 TO M l CHECK W IPER OPERATIONS B n tiV iU o nwtt> i *’I M l v :--v hr xJ*': iO fl j!c: W IP ER S DO NOT OPERATE N ORM ALLY ru inun j i r m i s . tri , *j*?.sq iw<: j r i ! oi •:* rim j&i,] y j lliiM umuo fe’fix (u?!>b .j', ' REFER TO W IND SHIELD W IPER DIAGNOSIS H Dum ? w D ETERM IN E CONTROLLER IS P R O P ER LY CONNECTED * )p iTfki 8) -in '■ CONTROLLER CONNECTED ^ I -3 8 S jSjSIi GJ T .b __________________________ gnniv/ toyartjpaLCI FUNCTIONS RELAY PR O PER LY CHECK W IPER SW ITCH (SEE PRO CEDU RE) K! m A:r SWITCH OK W IPER OPERATE N O R M A LLY REPAIR DAM AGED OR DISCONNECTED H AR N ESS TEST RELAY (SEE PRO CEDU RE) 15v'j ' " j Q ’ |»fn Tod'.’K'' RELAY DOES NOT FUNCTION .n? h . ,T >•'* ’> :GfT ' • •j •c v ia ;.! REPLACE CONTROLLER REPLACE RELAY =L SW ITCH DEFECTIVE S Y S T E M IS R ESTO RED REPLACE SWITCH " ..... 1 " S YST EM RESTORED SY S T E M IS RESTORED r~ SYST EM RESTORED z Dark Blue If the w iper/w asher selecto r sw itch is su sp ected o f being faulty, it can be ch eck ed with an ohm meter as indicated in table below . Before perform ing any continuity ch eck on selector sw itch , d iscon n ect both harness con n ectors from sw itch to controller. N e x t, place selecto r sw itch in m ode desired and perform a continuity ch eck betw een the indi­ vidual leads as indicated in table b elow , Figure 15. If there is a meter reading at each ch eck but no indication o f shorts, sw itch can be assum ed to be good. .■ i if- *J* control) -J in on — o press s= o (Oft Mode Mist Selector Switch Checking Procedure W ash Control bh-i (Rotate ;q#jo-,brf* Delay : t'.; /joa i :>u: Delay uq bns full clock w ise) 01 O' X Light Blue X Green X X Black X X Black Wht Str X X X X X X X X X X X X X X Orange X White X X off odi riguoidt .Hjfunfi'M- ■■ • :B /Gig 3fii oi )» rt.. LIGHT TRUCK SERVICE MANUAL 8C-32 INSTRUMENT PANEL AND GAGES ON-VEHICLE SERVICE WIPER MOTOR C-K Models Replacement (Fig. 8C-17) 1. Make sure wiper motor is in Park position. 2. Open hood and disconnect ground cable from battery. 3. Disconnect electrical harness at wiper motor and hoses at washer pump. 4. Reach down through access hole in plenum and loosen wiper drive rod attaching screws. Remove drive rod from wiper motor crank arm. 5. Remove wiper motor to dash panel attaching screws and remove the motor assembly. 6. To install, reverse Steps 1-5 above. Lubricate wiper motor crank arm pivot prior to reinstallation. Replacement (Fig. 8C-18) 5. 6. 7. 8. 9. NOTICE: Install wiper in the PARK position. Lube wiper motor crank arm pivot prior to installation. UNIT REPAIR WIPER MOTOR Repairs to the motor/gear box section of the wiper are limited to the switch, armature, and cap and brush holder assy., plus the external parts such as the crank arm, spacer/ seal (plastic) and output shaft seal. PARK SWITCH This is part of the washer pump relay coil assembly. Refer to figui e 8 C -19. Removal G Series 1. 2. 3. 4. 10. Remove three screws securing wiper motor to cowl and lift wiper motor out from under dash for further disassembly on bench. 11. To install, reverse Steps 1-10 above. Make sure wiper motor is in Park position. Open hood and disconnect battery ground cable. Remove wiper arms from wiper transmission linkage. Remove remaining screws securing cowl panel cover and lift off. Loosen nuts holding transmission linkage to wiper motor crank arm and lift linkage off arm. Disconnect power feed to wiper motor at multiple connector. Remove left dash defroster outlet from flex hose and push hose aside for access to wiper motor screws. Remove one screw securing left hand heater duct to engine cover shroud and slip heater duct down and out. Protect carpet, then remove windshield washer hoses from washer pump. 1. Disconnect wiring from wiper assembly and remove washer pump cover. 2. Remove pawl spring. 3. Push in retainer tab to release relay coil-park switch assembly from washer frame. 4. To re-assemble, reverse steps 1 thru 3 and check wiper operation, figure 8C-19. ARMATURE ASSEMBLY END CAP-BRUSH HOLDER ASSEMBLY Replacement 1. Bend retainer tabs as required to provide clearance for removing end cap assembly. Figure 8C-20. 2. To assist in pushing the end of the motor housing, rotate crank arm clock-wise (looking at crankarm). 3. Pull end cap assembly off the arm ature shaft and pull arm ature out of wiper housing. Replace Fig. 8C-17--Wiper M otor (C-K Series) LIGHT TRUCK SERVICE MANUAL 1. Release brush spring tension figure 8C-21 and slide brushes back in their respective brush holders. 2. Assemble a r m a tu re in end cap assembly and re­ position brush spring legs behind their respective tabs, figure 8C-22. 3. To maintain the end cap in its assembled position on arm ature shaft during re-assembly of arm ature in the wiper housing proceed as follows: Using small wire such as tag wire, tie arm ature to end cap assembly as shown in figure 8C-23. 4. Guide a rm a tu re worm shaft through the housing bearing. The strong magnetic field will pull arm ature toward one of the magnets. It will be necessary to overcome the magnetic force to start shaft into the bearing. 5. Guide terminal housing of end cap into the slot area of the wiper housing. INSTRUMENT PANEL AND GAGES 8C-33 Fig. 8C -1 8--W ip er M o t o r ( G Series) 6. Remove wire used to attach arm ature to end cap. This should be done before end cap enters the housing. 7. After wire is removed, rotate crank arm slightly to permit armature worm shaft to engage gear teeth. The end cap assembly can then be pushed into the housing until it bottoms against the end of the housing. 8. Bend the 4 tabs as required to secure the end cap in position figure 8-11. 9. Check wiper operation. CRANK ARM, SPACER, SEAL Refer to Figure SC24 Replacement 1. Remove crank arm retaining nut, crank arm, shaft seal and spacer in the order indicated. When re-assembling the shaft seal, be sure flat side is toward crank arm. 2. When re-assembling the crank arm, be sure wiper motor is in park (refer to figure 8C-25), and assemble crank arm on shaft in position shown in Figure 8C-25. WASHER PUMP Relay Coil This is part of park switch assembly. Refer to "P ark switch" for disassembly-assembly procedure. Ratchet Paw l Refer to Figure 8C-26. 1. Disconnect pawl spring. 2. Rem ove"e" type retainer ring and slip pawl off of shaft. Dog Spring: Refer to Figure 8C-26 1. Remove screw th a t atta c h e s dog spring to washer frame. Ratchet Gear: Refer to Figure 8C-26 1. Remove dog spring and ratchet pawl. 2. Move leg of retainer spring out of shaft groove and slide ratchet gear off shaft. Be careful not to lose retainer spring. 3. To re-assemble gear, reverse steps 1 and 2 but read note. In order to push gear on shaft until it bottoms, move ratchet pawl shaft in a direction away from the gear. LIGHT TRUCK SERVICE MANUAL 8C-34 INSTRUMENT PANEL AND GAGES C O N N E C T IO N S TO O P E R A T E W IP E R S IN D E P E N D E N T L Y OF V E H IC L E W I R I N G A N D D A S H S W ITC H. NO LOAD CURRENT DRAW @ 12V Lo Speed — 2.5 Amps Max HI Speed — 5.0 Amps Max Crank Arm Rotation — CCW (Looking at Arm) LO SPEED 12V( PARK Fig. 8C -19--Checking M o t o r Op eration This will allow gear collar to slide past the tab on the piston actuator plate. (Refer to Figure 8 C -12). 3. Remove valve assembly as required. 4. To re-assemble, reverse steps 1 thru 3. Piston and Housing Assy: Refer to Figure 8C-27. 1. Remove ratchet pawl, dog spring and ratchet gear. 2. Pull piston housing away from frame until the mount­ ing grooves clear the frame. During this step the piston spring is being compressed. LIGHT TRUCK SERVICE MANUAL Valve Assembly: Refer to Figure 8C-26. 1. Remove the four (4) attaching screws and remove valve assembly and gasket ring. 2. During re-assembly, be sure seal is properly installed in piston housing and valve assembly grooves. INSTRUMENT PANEL AND GAGES 8C-35 B E SU RE BRUSH L E A D S ARE ROUTED CO RR EC T LY A N D A R E N O T T O U C H IN G E A C H OTHER B R U S H S P R IN G L E G IN C O R R E C T P O S IT IO N F O R R E - A S S E M B L Y IN M O T O R (3 S P R IN G S ) S P E E D BRUSH LEA D ROUTED CO RRECTLY NOTE: B E SU R E LO W ER B R U S H S P R IN G L E G S A R E IN B R U S H H O L D E R S L O T S Fig. 8C -20--Relay Coil Assembly B R U S H S P R IN G IN R E L G A S E D P O S IT IO N (3 S P R IN G S ) Fig. 8C-22--Brush S p r in g -B r u sh Spring-Released Position R O T A T E BRUSH SP R IN G IN D IR E C T IO N B R U S H S P R IN G LEG OF AR R O W TO RE­ RELEASED FROM RE­ P O SITIO N IT B E H IN D R E T A IN E R NOTCH T A IN E R NOTCH R E T A IN E R NOTCH Fig. 8C-21--Releasing Brush Spring Tension Fig. 8C-23--End C ap Assembly LIGHT TRUCK SERVICE MANUAL 8C-36 INSTRUMENT PANEL AND GAGES — NUT ” TRUCK CRAN K ARM P A R K P O S IT IO N CRANK ARM SHAFT SEA L (RUBBER) SP A CER (PLASTIC) ARMATURE END PLAY ADJUSTING SCREW “A X ” - I D E N T I F IC A T IO N C O D E “G ” V A N C R A N K A R M P A R K P O S I T IO N A Y - ID E N T IF IC A T IO N CODE Fig. 8C -24--C ra n k A rm Sp a ce r Seal Fig. 8C-2 5--C ra nk A rm Park Position LIGHT TRUCK SERVICE MANUAL INSTRUMENT PANEL AND GAGES 8C-37 P A W L S P R IN G “E ” R E T A IN E R R IN G L E G O F R E T A IN E R IN R A T C H E T G E A R SH AFT GROOVE D O G S P R IN G RATCHET G EA R Fig. 8C-26 --W ash er Pump Assembly LIGHT TRUCK SERVICE MANUAL 8C-38 INSTRUMENT PANEL AND GAGES M O U N T IN G G R O O V E (Both Sides) Fig. 8 C -2 7 ~ W a s h e r Pump Exp loded View WINDSHIELD WIPER AND WASHER P MODELS GENERAL DESCRIPTION The system consists of a compound wound rectangular­ shaped motor attached to a gear box containing a parking switch in addition to the gear train. The gear train consists of a motor a rm a tu r e helical gearshaft which drives an intermediate gear and pinion assembly. The pinion gear of the intermediate gear and pinion drives an output gear and shaft assembly. Turning the wiper switch to the LO speed position completes the circuits from the wiper terminals 1 and 3 to ground. C u rre n t then flows from the battery via wiper terminal No. 2 through the series field and divides; (1) part passes through the arm ature to ground via wiper terminal No. 1 to the wiper switch and (2) the second part passes through the shunt field to ground through wiper terminal No. 3 to the wiper switch (fig. 8C-28). LIGHT TRUCK SERVICE MANUAL NOTICE: The wiper switch must be securely grounded to body metal. Moving the wiper switch to the HI speed position opens the shunt field circuit to ground at the switch. However, the shunt field is connected to a 20 ohm resistor which is connected across wiper terminals 1 and 3. The shunt field current then flows via terminal No. 3 through the resistor to terminal No. 1 to the switch, to ground (fig. 8C-29). The parking circuit covers th a t portion of wiper operation when the wiper switch is turned "off" and the wiper blades have not reached the park position. When the wiper blades are not in the normal park position, the parking switch contacts are still closed. The INSTRUMENT PANEL AND GAGES 8C-39 PER GEAR TRAIN DA S H WIPER TERMINAL S WI TC H BOARD PARK I S WI TC H TOTX GRAY ig n it io n SHUNT F - NAT. W I R E / S WI TC H Fig. 8 C -2 8 --L O Spe ed Circuit wiper will continue to operate until the wiper output gear is turned to a position where its cam opens the park switch. Referring to Figure 8C-30, it can be seen that the wiper motor circuits are completed to ground through the parking switch. I■ 1Jji 51"*j.i switch to ground. The series field and arm ature circuit is also completed from terminal No. 1 through the parking switch to ground. The shunt field is connected direct to ground, by­ passing the resistor. This results in LO speed operation during the parking operation. The wiper motor must be securely grounded to body metal. The shunt field circuit is completed from terminal No. 3 via the switch to terminal No. 1 through the parking W hen the o utput gear cam opens the park switch contacts, the wiper is OFF. LIGHT TRUCK SERVICE MANUAL 8C-40 INSTRUMENT PANEL AND GAGES PARK SWITCH SERIES F* DASH SWITCH OFF-LO-Hl SHUNT F - NATURAL WIRE Fig. 8C-29--HI Sp e e d Circuit Fig. 8 C - 3 0 - P A R K IN G C ircuit DIAGNOSIS WIPER - ON VEHICLE 1. Inspect for the following items: a. Wiring harness is securely connected to wiper and switch. b. Wiper motor is securely grounded to body. c. Wiper switch is securely mounted and grounded. d. Check fuse. 2. If items in Step 1 check out, try operating wiper in both " L O " and " H I " speeds, then turn wiper off (blades should return to park position). If wiper fails to operate correctly, proceed to Step 3. 3. Disconnect wiring harness from wiper and try operat­ ing wiper as shown in Figure 8C -3 1. LIGHT TRUCK SERVICE MANUAL a. If wiper operates correctly independently of switch and vehicle wiring, refer to the D IA G N O S I S C H A R T - W IP E R O N V E H IC L E . b. If wiper still fails to operate correctly in Step 3, disconnect wiper linkage from motor crankarm and try operating wiper again. If wiper opeates correctly independently of linkage, check linkage for cause of wiper malfunction. c. If wiper fails to operate correctly independently of linkage, remove wiper motor from vehicle and refer to D IA G N O IS C H A R T -W IP E R O F F V E H IC L E . INSTRUMENT PANEL AND GAGES fiC-41 DIAGNOSIS - WIPER ON VEHICLE NOTE: Ignition switch m u st be "on" for all electrical tests. C O N D IT IO N A PPA R E N T CAUSE C O R R E C T IO N A. Blown fuse A. L o c ate s h o rt circuit a n d repair. R ep lace fuse. B. O pen circuit in feed wire (No. 2 term in al on wiper m o to r) B. L o ca te b ro k e n wire and re p a ir : I C. Loose m o u n tin g of wiper switch C. T ig h te n sw itch mountirig D. Defective w iper switch D. R e p la c e sw itch E. O pen circuit in wire to wiper switch (No. 1 term inal on wiper m o to r) E. L o c a te b ro k e n wire a n d rep air A. G r o u n d e d W ire (No. 1 term inal on w iper m o to r) to w iper switch A. L o c a te sh o rt circuit a n d rep air A. Defective w iper switch A. R e p la c e w iper switch B. G r o u n d e d wire (No. 3 term inal on wiper m o to r) to wiper switch B. L o ca te a n d repair short circuit A. Defective w iper switch A. R e p la c e w iper switch B. O pen circuit in wire (No. 3 term inal on wiper m o to r) to w iper switch B. L o c a te a n d repair broken wire 3. W iper has "H i" speed only A. O p en circuit in wire (N o. 3 te rm in a l on wiper m o to r) to w iper switch A. L o c ate b ro ken wire a n d rep air 4. W ip e r has "L o" speed only A. G r o u n d e d wire (N o. 3 term inal on wiper m o to r) to w iper switch A. L ocate short circuit and rep air B. Defective wiper switch B. R e p la c e wiper switch A. Loose wiper g ro u n d strap connectio n A. T ig h te n strap co n n e c tio n 1. W ip er Inoperative or in te rm itte n t 2. W ip e r will not shu t off: A. W iper has both "L o" and "H i" speeds B. W ip e r has "L o" speed only C. W ip er has "H i" speed only 5. Blades do not r e tu rn to full p a rk position j I t > LIGHT TRUCK SERVICE MANUAL 8C-42 INSTRUMENT PANEL AND GAGES DIAGNOSIS - WIPER OFF VEHICLE C O N D IT IO N 1. Wiper In o p e ra tiv e or In te rm itte n t A PP A R E N T CAUSE C O R R E C T IO N A. B ro ken or d a m a g e d gear train (only if inoperative) A. R ep lace gears as required B. P o o r solder c on nection s at te rm in al b oard B. R e so ld e r w ires at term inals C. Loose splice jo in ts at b ru sh plate C. R e c r im p o r solder splice joints D. Brushes binding in b ru sh ho ld e r D. C lean h o ld e r o r replace bru sh , sprin g o r b ru sh plate assembly. E. O p e n circuit in a r m a tu r e E. R eplace a r m a t u r e A. Defective p a rk switch A. R ep la c e te rm in a l board assembly B. G r o u n d e d red lead wire B. R e p a ir sh o rt circuit in red wire A. G ro u n d e d sh u n t field coil A. R ep la c e f ra m e and field assem bly B. G r o u n d e d black wire B. R e p a ir sh o rt circuit in black wire A. O p en circuit in sh u n t field coil A. R e pla c e fra m e a n d field assem bly B. O p en circuit in black wire B. R e p a ir b ro k e n wire or p oo r solder c o n n e c tio n 3. W ip e r sh u ts off - but not in p a rk position A. P a r k switch defective or c o n ta c ts dirty A. R ep lace te rm in a l bo ard assem bly o r clean con ta c ts 4. "H i" speed too fast A. R esisto r defective A. R e p la c e te rm in a l board assem bly 2. W iper will n ot shut-off: A. W iper has n o rm a l "H i" an d "Lo" speed B. W ip e r has " L o " speed only C. W ip e r has " H i" speed only LIGHT TRUCK SERVICE MANUAL INSTRUMENT PANEL AND GAGES 8C-43 LO SPEED - AS SHOWN HI SPEED - DISCONNECT JUMPER WIRE FROM TERMINAL NO. 3. OFF - LEAVE JUMPER CONNECTED TO NOS. 1 & 3 BUT DISCONNECT IT FROM GRD. STRAP. WIPER SHOULD STOP WITH GEAR SHAFT FLATS AS SHOWN. WIPER GROUND STRAP Fig. 8C-31--Jumper W ir e Connections Fig. 8C -3 3-Testing Field Coils TEST LIGHT PROBES FOR GROUND CHECK. IF LAMP LIGHTS, ARMATURE IS CHECK FOR POOR WELD JOINTS TEST LIGHT PROBES, BAR TO BAR CHECK FOR OPENS - LAMP SHOULD LIGHT BETWEEN ADJACENT BARS Fig. 8C-32--Checking Armature LIGHT TRUCK SERVICE MANUAL 8C-44 INSTRUMENT PANEL AND GAGES DIAGNOSIS - WASHER SYSTEM C O N D IT IO N A PPA R E N T CAUSE C O R R E C T IO N 1. W a sh e rs inoperative A. In a d e q u a te q u a n tity of w a sh er solution A. A d d w a s h e r solution B. H oses d am a g e d o r loose B. C u t s h o rt le n g th off end o f hose to insure air tight co n n e c tio n o r replace hose C. Plugged screen at end o f j a r cover hose C. C lean screen D. Loose electrical con nection to w asher p u m p or wiper switch D. C h e c k electrical c o n n e c tio n s a n d re p a ir if necessary E. O pen circuit in feed wire to ratchet relay coil E. L o c a te op en circu it a n d re p a ir F. W ip e r switch defective F. R e p la c e w ip e r sw itch G . R a tc h e t relay coil defective G . R ep lace r a tc h e t relay H. W a sh e r nozzles plugged H . C lean w a s h e r nozzles I. R a tc h e t wheel too th missing I. R e p la c e r a tc h e t wheel J. R a tc h e t pawl spring missing J. R e p la c e r a tc h e t paw l spring K. D efective p u m p valve assembly K. R e p la c e p u m p valve assem bly A. G r o u n d e d wire from ra tc h e t relay to switch A. L o c a te g ro u n d e d wire a n d re p a ir B. W ip e r switch defective B. R e p la c e w ip er sw itch C. R a tc h e t wheel tooth missing C. R e p la c e ra tc h e t wheel D. R a tc h e t wheel dog b roken o r not c on ta c tin g ratchet wheel teeth D. R e p la c e o f re p a ir ra tc h e t wheel do g E. L oc k -o u t tan g b ro k e n o r bent on piston a ctu a tin g plate E. R ep lac e p iston a c tu a tin g p late 2. W a sh e r p u m p s co ntin ously w hen wipers are o p e ra tin g LIGHT TRUCK SERVICE MANUAL INSTRUMENT PANEL AND GAGES 8C-45 ON-VEHICLE SERVICE WIPER MOTOR Wiper motor replacement procedures are not included here since installation is performed by the individual body manufacturers; however, disassembly of the unit will be covered. UNIT REPAIR 5. Drill out gear box cover retaining rivets, remove cover from gear train. Screws, nuts and lockwashers for reassembling cover to wiper are contained in the service repair package. 6. Remove output gear and shaft assembly, then slide intermediate gear and pinion assembly off shaft. 7. If necessary, remove terminal board and park switch assembly as follows: a. Unsolder motor leads from terminals. Code motor leads. b. Drill out rivets securing terminal board and park switch ground strap to mounting plate. Screws, nuts and washers for attaching a replacement terminal board park switch assembly are included with the replacement assembly. WIPER MOTOR Disassembly (Fig. 8C-34) Gear Box 1. Remove the two washer pump mounting screws and lift pump off washer. 2. Remove washer pump drive cam as required (figs. SC33 and 8C-34). The cam is pressed on the shaft but can be wedged off by using two screwdrivers between cam and plate. 3. Clamp crank arm in a vise and remove crank arm retaining nut. NOTICE: Failure to clamp crank arm may result in stripping of wiper gears. 4. Remove crank arm, seal cap, retaining ring, and endplay washers. Seal cap should be cleaned and repacked with a waterproof grease before reassembly. Motor 1. Follow Steps 1 through 7b under gear box disassembly. 2. Remove motor through bolts, tap motor frame lightly, and remove motor from mounting plate. REMOVE BRUSH SPRING FROM SLOT A N D PLACE IT IN GROOVE AS SH O W N 1. 2. Nut Crank Arm 7. 3. 4. Seal Cap Retaining Cap 8. 5. Washer 6. G e a r Box Cover O u tp u t Gear and 11. Brush Plate Assembly and 15. Armature M ounting Brackets 16. Thrust Plug Brushes W ave Washers 17. Frame and Field W ave Washer 12. 13. 18. End Plate G e a r Box Housing 14. Flat Washers 19. Tie Bolts (Two Required) Shaft Assembly 9. 10. Interm ediate G ear Fig. 8C-34--Wiper M otor and G ear Box Assembly LIGHT TRUCK SERVICE MANUAL 8C-46 INSTRUMENT PANEL AND GAGES 3. Remove brush spring tension (fig. 8C-34), slide a rm a­ ture and end plate from motor frame. Pull end plate from armature. Thrust plug located between arm ature shaft and end plate. 2. Place wiper in park position and install crank arm on output shaft, rotate crank so alignment marks line up with those on cover (fig. 8C-36). 3. Replace retaining nut, place crank arm in vise, tighten retaining nut. 4. Remove end play adjusting washers from armature, noting arrangement for proper reinstallation. WINDSHIELD WASHER Inspection Check and inspect all parts for wear; replace as necessary. All parts can be replaced individually except motor frame and field, which is serviced as an assembly. Service kits also provide screws, nuts and washers to replace gear cover and terminal board rivets. Assembly Refer to Figure 8C-34 for exploded view of motor and gear train. The positive displacement washer pump used on the two-speed non-depressed park wipers (fig. 8C-37) use a pump mechanism consisting of a piston, piston spring and valve arrangement driven by a (4) lobe cam, and follower assembly (fig. 8C-39). The cam is attached to one shaft of ------G E A R C A S E G R O O V E S — CRANK ARM GROOVES Motor Reassem ble motor using reverse of disassembly procedure. A rm ature end play is controlled by end play washers. See Figure 8C-35 for proper assembly of end play washers. Lubricate arm ature shaft bushings with light machine oil. Gear Box 1. Assemble gear box using reverse of disassembly procedure. Lubricate gear teeth with Delco Cam and Ball Bearing lubricant (or equivalent). Be sure cover is properly located over dowel pins and be sure to reinstall ground strap. Fig. 8C -36 --W ip er M o t o r C ra n k A rm in Park Position PUMP M OUNTING SCREWS LIGHT TRUCK SERVICE MANUAL INSTRUMENT PANEL AND GAGES 8C-47 SO L EN O ID COIL VALVE ASSEM BLY \ _ \ SO LEN OID PLUNGER RATCHET PAWL SPRIN G C A M FOLLOW ER UPPER PIN 4 LOBE C A M (PRESS FIT O N SHAFT) "E” R IN G CAM FOLLOW ER RATCHET PAWL Fig. 8C -4 0 --W ash er Pump Mech anism terminal with no tang (fig. 8C-37). Incorrect installa­ tion of connector will result in direct ground and destroy wiper motor fuse. Fig. 8 C -3 8 ~ W a s h e r Pump Drive C a m the wiper motor output gear (fig. 8-49). Programming is accomplished electrically and mechanically by a relay assembly and ratchet wheel arrangement. Replacement 1. Disconnect battery ground cable. 2. Remove two pump mounting bolts. 3. Remove washer pump assembly. 4 .sTo install reverse Steps 1-3 above. Install washer m ultiplug harness connector with b attery lead on )isassembly-Assembly (Figures 8C-40 thru 8C-43) 1. Remove washer pump cover by squeezing. 2. Solenoid assembly - ratchet dog. a. Remove ratchet dog retaining screw. Hold spring loaded solenoid plunger in position and carefully lift solenoid assembly and ratchet dog off frame of pump. b. Separate ratchet dog from solenoid mounting plate as required. 3. Ratchet pawl. a - Disconnect ratchet pawl spring. RATCHET D O G R ETAINING SCREW SOLENO ID ASSEMBLY RATCHET PAWL SPRING VA LVE ASSEMBLY M O U N T IN G SCREW FRAME ft \ RATCHET PAW L RATCHET G R O O V ES BOTH SIDES Fig. 8C-39--Washer Pump Drive Cam and Actuator WHEEL J. Fig. 8C-41--Washer Pump-Exploded View LIGHT TRUCK SERVICE MANUAL 8C-48 INSTRUMENT PANEL AND GAGES b. Remove ratchet pawl retaining ring and slide ratchet pawl off cam follow ;r shaft. 4. Ratchet wheel. a. Follow Step disassembly. 1 under solenoid - ratchet dog b. Move ratchet wheel spring out of shaft groove and slide ratchet wheel off its shaft. 5. Pump and actuator plate assembly. a. Remove solenoid assembly - ratchet pawl and ratchet wheel as outlined in their respective procedures. b. To seperate pump and pump actuator plate from frame, pull pump housing in direction of the arrow until grooves in housing clear the frame. Then remove actuator plate from ratchet wheel and cam follower shafts. 6. Valve assembly. Fig. 8C-42--Releasing Pump From Lockout Position a. Remove four screws that attach the valve assembly to pump housing. During assembly, be sure gasket between housing and valve plate is properly positioned in housing and valve plate grooves. Also be sure triple " O " ring is properly installed between valve body and pipe assembly. WIRING DIAGRAMS Body and Chassis Wiring Diagrams and circuit identi­ fication charts are shown on the pages which follow. LIGHT TRUCK SERVICE MANUAL INSTRUMENT PANEL AND GAGES 8C-49 FROM WASHER JAR N U K E STROKE INTAKE VA L V E CLO SED EXHAUST STR O K E Fig. 8C-43--Cross Section of Windshield W a s h e r Pump Valve W IRE S IZ E C O N V E R S IO N T A B L E M E T R IC S IZ E (mm)2 .22 .5 .8 1 2 3 5 8 13 19 32 AWG S IZ E 24 20 18 16 14 12 10 8 6 4 2 LIGHT TRUCK SERVICE MANUAL 8C-50 INSTRUMENT PANEL AND GAGES E L E C T R IC A L C IR C U IT ID E N T IF IC A T IO N Circuit Circuit Number C o lo r C ir cu it N a m e 2 Red Feed, Batt ery - U n fu se d 3 Pink Feed, Ign. Sw. " O n & C r a n k " Con trolled, U nfu sed 4 Brown Feed, Ign. Sw. " A c c s y & O n " Circuit C ircuit Number C o lo r C ir cu it N a m e 39 Pin k - B la c k Feed, Ign. S w . " O n and C r a n k " 40 Orange Feed, Battery - Fused 41 Br o w n -W h ite Feed, Ign. Sw. " A c c s y and 42 Yellow Feed, A / C A u t o Rela y C o n t r o ll e d C o n tr o lle d - Fused Controll ed, Unfu se d O n " C o n tr o ll e d - Fused 5 Y e l lo w Neutral Safety Start Sw. or Start Relay Feed 43 Yellow R a d i o Feed 6 Purple Starter S o le n o i d Feed 44 D a r k Green I.P. and Lights Feed (U sually 7 Y ellow Prim ary Ign ition Resistance 45 B lack M a rke r and Clearance L a m p s 46 D a r k Blue Rear Seat S pe ak er Feed F r o m 47 D a r k Blue A u x il i a r y C ir c u it (Trailer) 48 Gray Tail Lp. - H e a d la m p Sw. " O n " - By-Pass 8 Gray In str u m ent and Panel Lights (Fused No. 44 Cir.) 9 Brown L ight S w . to Fuse) (Trailers) Tail, License, Park and Side M a r k e r L a m p Feed 10 Y ellow D i m m e r Sw. Feed 11 Light Green H e a d la m p Feed, H i-B e am 12 Tan H e a d la m p Feed, L o -B e a m 13 Purple F r o n t Parking L a m p s 14 Light Blue L.H. Indicato r and Front S in gle R a d i o or R ig h t Stereo or Dir. S ig na l and S t o p H e a d la m p Sw. " O f f " Rear L.H. 49 D a r k Blue or Dir. S ig na l and S t o p - Directional La m p s 15 D a r k Blue R.H . Indicato r and F ront 16 Purple Direction al Signal Sw., Feed 17 White Direction al Sig nal Sw., Feed H e a d la m p Sw. " O f f " Rear R.H . 50 Brown Feed, Ign. Sw. " O n " C o n tr o lle d - 51 Yellow Blo w e r Resistor Feed - L o w 52 Orange Feed, B l o w S w . " H i " or Direction al La m p s F r o m Flasher Fused Selector Sw. " M a x C o l d " F r o m S t o p Sw. 18 Y e l lo w S t o p and Directional L a m p C o n tr o lle d 53 L ight Green Valve Release S o le n o i d to 54 D a r k Green C o n tr o l to Shie ld or Direction al L a m p O n l y - Rear L.H. 19 20 D a r k Green Tail Lp. - H e a d la m p Sw. " O n " - C o n tr o l B o x S t o p and Directional L a m p or 55 Orange K i c k D o w n S o le n o i d Feed Directional L a m p O n l y - 56 Tan A m p li f i e r to Tra n sdu c er Rear R.H . 57 Orange L.H. C o r n e r in g L a m p Feed Black D a r k Green R.H . C o r n e r in g L a m p Feed C o m p r e s s o r Feed Lig h t Blue S t o p L a m p (O nly) 21 Pink S p o t Light 58 59 22 White Direct G r o u n d - Trailer 60 Or a n g e -B la c k Feed, Battery, C ir c u it Breaker 24 Light Green B a c k U p L a m p Feed 25 Brown Feed, V o lta g e R egula to r 61 Y e l lo w G r o u n d , Resistive, A u t o A / C 26 D a r k Blue Field Cir cu it (F ) (G e n /R eg.) 62 Light Green G r o u n d , Resistive, A u t o A / C 27 Brown T ra f f ic Hazard Sw., Feed F r o m 63 Tan Feed, B lo w e r Sw. " M e d i u m 1 " 64 Brown B lo w e r Sw. Feed F r o m A / C 65 Purple Blo w e r M o t o r Feed 66 L ight Green Feed, A / C S ele ctor Sw. C o n tr o lle d 67 L ight Blue Feed, A / C F reon Press, C u t - O u t 68 Y e l lo w - B la c k G r o u n d , Resistive, L o w C o o la n t 69 Gray G r o u n d L o w C o o la n t M o d u l e 70 Pin k Feed, R e la y C on trolled , Ign. Protected C on trolled Hazard Flasher 28 B lac k G r o u n d , H o r n Sw. C o n troll ed 29 D a r k Green H o r n Feed 30 Pi nk Fuel G a u g e to T a n k Unit 31 T an Oil Pressure, Engine 32 Y e l lo w M a p L igh t Feed 33 T an -W h ite W a r n in g L igh t - Brake 34 Purple F o g or Drive L a m p 35 D a rk Green G r o u n d , Eng. C o o la n t Temp. Sw. or E C M C o n troll ed (H ot) 36 Light Green L ight Green D a rk Blue LIGHT TRUCK SERVICE MANUAL C o n tr o lle d Sele ctor Sw. (C o m p . Ct.) Sw. C o n t r o ll e d Probe C o n tr o lle d G r o u n d , Eng. Metal T em p. Sw. C o n tr o lle d (H ot) 38 Feed B a c k Pot C o n tr o lle d G r o u n d , Eng. Tem p . Sw. C o n tr o lle d (Cold) 37 A m b . S e n so r C o n tr o lle d Flasher Fused Feed C o n tr o lle d Sw. C o n tr o ll e d INSTRUMENT PANEL AND GAGES 8C -S1 E L E C T R IC A L C IR C U IT ID E N T IF IC A T IO N (Cont'd) C ir cu it Cir cu it C o lo r Number - ' B la c k 71 C ir c u it N a m e G r o u n d , A / C Selector Sw. " D e f " Circuit C ir cu it Number C o lo r 131 B la c k -P in k G en e ra to r (A lt ern ator) Ext. 132 W hite G r o u n d , Fuel E c o n o m y Sw. 133 Y ellow G r o u n d , Fuel E c o n o m y Sw. 135 D a r k Green Resist. 1 O h m / F o o t C o n tr o lle d 72 L ight Blue Feed, Blo w e r Sw. " M e d i u m 2 " 73 Purple-White Feed, B lo w e r Sw. " M e d i u m 3 " 74 L ight Green Feed to T h ro tt le S w it c h 75 D a r k Blue Feed, Ign. Sw. " O n and C r a n k " Con troll ed, A m b e r Telltale C o n tr o lle d Con troll ed, Grn. Telltale C o n tr o lle d W hite G r o u n d , Resistive, Tem p . G a uge 139 P in k - B la c k Feed, Ign. Sw. " O n and C r a n k " S e n so r C o n tr o lle d C o n tr o lle d - Fused Feed, Ign. Sw. C o n tr o lle d C ir cu it N a m e 76 P in k 78 L ight Blue Electric C h o k e Feed 80 L ight Green G r o u n d K e y W ar n in g Buzzer 140 Orange Feed, Batt ery - Fused 81 Nat. White Electric R e m o t e Mirror, R ig h t 141 B r o w n -W h ite Feed, Ign. Sw., " A c c s y and O n " 82 L ig h t Blue Electric R e m o t e Mirror , Left 83 D a r k Green Feed, Cruise E ngage Sw. 142 B lac k R r C o m p a r t m e n t Lid L o c k 84 D a r k Blue Feed, Cruise E ngage Sw. 143 P in k Feed R a d i o Sw. " O n " C o n tr o lle d " E n g a g e " C o n tr o lle d 144 Y ellow Feed to Pw r A n t Sw. 85 W hite G r o u n d , Cruise In dicator 145 D a r k Green Feed, Pw r A n t Up, R ela y C o n ­ 146 D a r k Green G r o u n d , T r u n k Release Tell-Tale C o n tr o lle d - Fused C o n tr o lle d Release " R e t a r d " C o n tr o lle d trolled R e gu la to r C o n tr o lle d 86 Brown Feed, Cruise Brake Release Sw. 150 B lac k G r o u n d C ir c u it - Direct 88 Y e l lo w Electric R e m o t e Mirror, U p 151 B lac k G r o u n d C ir c u it - Direct 89 L ight Green Electric R e m o t e Mirror, D o w n 152 B lac k G r o u n d C ir c u it - Direct 90 Pink Feed, C u t o u t Sw. Controll ed, 153 B lack G r o u n d C ir c u it - Direct 154 B lac k G r o u n d C ir c u it - Direct 155 B lack G r o u n d C ir c u it - Direct 156 W hite G r o u n d C ir c u it - Sw. C o n tr o lle d C o n tr o lle d Cir. Brkr. Protected Gray W in dsh ie ld W ip er - L o w 92 Purple W in d s h ie ld W ip er - Hi 93 W hite W in d s h ie ld W ip er M o t o r Feed B o d y Interior L a m p s - such 94 95 Pin k D a r k Green W in dsh ie ld W as her Sw. to Washer G r o u n d , Pulse W ip er Sw. as D o m e , Courtesy, M a p , 91 C o n tr o lle d 96 Brown W arning, etc. 157 Gray Feed, Pulse W ip e r R heosta t Sw. B o d y Interior L a m p s - such as C o n tr o lle d Black-W hite W in d s h ie ld W asher L o w Fluid 101 D a r k Blue R esistor O u t p u t to Blo w e r R ela y 102 W hite S L A lte r n a to r - Regu la to r 99 G r o u n d C ir c u it - Sw. C o n tr o lle d D o m e , Cou rtesy, M a p, W ar n in g etc. 158 B lac k -O ra ng e G r o u n d C ir c u it - Sw. C o n tr o ll e d B o d y Interior L a m p s - such as Sen sin g Cir cu it D o m e , Cou rtesy, M a p, W ar n in g 105 B lack A m m e t e r - G enerato r 106 Gray A m m e t e r - Batt ery 159 T an 107 D a rk Blue Over Spe ed W a r n in g Light 160 W hite Po wer A n t e n n a D o w n 111 Black G r o u n d , A n t i - S k i L o w A ir Sw. 161 B lac k Pow er A n t e n n a U p 162 Gray Pow er T o p - U p 112 D a r k Green Telltale T em p era tu re G a u g e (H o t ) 163 Purple Pow er T o p - D o w n 115 L ig h t Blue Spe ak er Return, R T rr Stereo 164 D a r k Blue W i n d o w C o n tr o l L F U p 116 Y ellow S peaker Return, L F rr Stereo 165 Brown W i n d o w C on trol L F D o w n 117 D a r k Green S peaker Return, R T Frt. Stereo 166 D a r k Blue- 118 Gray S peaker Return, L F Frt. Stereo 119 W hite Gen e ra to r (A lt ernator) to 120 Purple Electric Fuel P u m p Feed 121 White 125 126 130 C o n tr o lle d etc. G r o u n d , K e y W a rn ing Buzzer W hite W in d o w Control R F Up Tan W i n d o w C o n tr o l R F D o w n 168 D a r k Green W i n d o w C on trol L R U p 169 Purple W i n d o w C o n tr o l L R D o w n T a c h o m e te r to C oil 170 L ight Green W i n d o w C o n tr o l R R U p Y ellow D o o r J a m b S w it c h 171 Purple-White W i n d o w C o n tr o l R R D o w n Blac k Seat B a c k L o c k Feed 172 Light Green V e n t C o n tr o l L F Close Br ow n -W h ite G enerato r (A lt ern ator) Ext. 173 Y ellow V e n t C o n tr o l L F O p e n Resist. 2 O h m s / F o o t 174 D a r k Green V e n t C o n tr o l R F C lo se R egu la to r 167 LIGHT TRUCK SERVICE MANUAL 8C-52 INSTRUMENT PANEL AND GAGES E L E C T R IC A L C IR C U IT ID E N T IF IC A T IO N (Cont'd) Circuit Circuit Number C o lo r Circuit N a m e Circuit C ir cu it Number C o lo r C ir c u it N a m e 175 Purple V e n t C o n tr o l R F Open 213 D a r k Blue 176 D a rk Green Po wer Seat Fore 214 Gray R H Seat Sen so r 177 Y e l lo w Po wer Seat A f t or Recline 21 5 T a n -B la c k L H Sw. 178 D a r k Green Po wer Seat - 6 -W ay Fore and 216 179 Tan Po wer Seat - 6-W a y S o le n o id Rear - U p and D o w n 180 Light Green D a r k BlueWhite A ft Center B u c k le Sw. (Feed) 217 G ray -W hite R H Sw. 218 D a rk Green Inte rlock R e la y - G r o u n d 219 L ight Green- Starter In te rloc k C on troll ed 22 0 Y e l lo w Starter In te rloc k B u z and Lp 221 Brown Passenger Initiator Feed, 22 2 D a r k Blue Passenger In itiator Return, L o w 223 Ligh t Blue Sen sor Detector Hi Return, L o w 224 Light Green S enso r D etec tor L o Feed, L o 225 D a r k Green W a rn ing L a m p G r o u n d I R W a rn ing L a m p Sen sor Po w er Seat - 6 -W a y S o le n o id F ront - U p and D o w n Center Seat S en sor (Pro vided b y Electronics) 181 L igh t Blue Power - S o le n o id - Fore and A f t 182 Yellow Po w er Seat - 6 -W ay - A f t and 183 L ight Blue Tailgate or Center Partition 184 T an-W hite Tailgate or Center Partition 185 Tan V e n t C o n tr o l L R Op en 186 Gray V e n t C o n tr o l L R Close 187 D a r k Blue V e n t C o n tr o l R R O p en 188 Ligh t Blue V e n t C on trol R R Close 189 D a r k Green Po wer Seat - 4 -W a y - Fore and 226 Orange 190 Y e l lo w Po wer Seat - 4 -W a y - A f t and U p 227 T an R ecorder to S enso r Pow e r Feed 191 L ight Green Po wer Seat - 4 -W a y S o le n o id - 228 Y e l lo w W a r n in g L a m p Feed 229 Pink Sen sor Detector Hi Feed, L o 192 Purple D efogger - Hi or Singl e Speed 193 Purple-White D efogger - L o w Speed - 0.38 230 Pink R ecorder Po w er Feed 231 Orange Driver Initiator Feed, I R 194 B lack Electric D o o r L o c k - U n lo c k 232 White Driver Initiator Return, I R 195 Ligh t Blue Electric D o o r L o c k - L o c k 233 D a r k Green Hi Level A c t u a t i o n Passenger 198 Ligh t Green Bl ack G r o u n d , Resistive, A / C In-Car 234 Yellow I R Feed, Ign. Sw. Con trolled, 199 Brown Rear Seat Speaker - Feed f r o m 235 Y e l lo w S en sor D etec tor Hi Feed - Hi 200 Light Green F r o n t Spe ak er - Feed F r o m R a d i o 236 Gray S en sor D etec tor Hi R etu rn - Hi 201 T an F r o n t S peaker - Feed f r o m R a d i o - 23 7 Y ellow Feed, Belt W arn T im e r C o n ­ 202 Bl ack G r o u n d , C o m p r e ss o r over Heat 238 B lack Seat Belt W arn S y s t e m - B u z z e r 203 Ligh t Blue Rear A / C Potentiomet er Feed 23 9 P in k - B la c k Feed, Ign. Sw. " O n & C r a n k " 24 0 Orange Feed, Battery - Fused 241 Purple S en sor Detector L o Feed, Hi 24 2 T an Feed, T h ro tt le C o n tr o l S p a r k 24 3 Black-W hite Feed, Dr ive Sele ctor Sw. C o n ­ 244 Purple Feed, L T F / D S o le n o i d R ela y 245 D a r k Blue Feed, R T F / D S o le n o i d R ela y 246 D a r k Green Feed, A D L L o c k R e la y C oil 247 Brown Feed, to A / C S h u t - O f f R e la y B lack Down Feed W in d o w Up L o w Level, I R W in d o w Dow n Down U p and D o w n O h m s per f o o t Level, I R Level, IR Feed, L o w Level, IR Level I R (Inactive) S enso r C on troll ed U n fu se d R a d i o Left Stereo Level IR Sin gle or R ig h t Stereo Level I R Left Stereo trolled ( T i m e d 3 9 Ct.) Sw. C o n troll ed 204 D a rk Blue T herm a l Lim iter Feed 205 W h it e-Bla c k Seat Belt Seat Sen sor t o Belt 206 D a r k Blue Neutral S ta rt Sw. to Buzzer R etr acto r (Grd) and L a m p 207 Y e l lo w 208 Gray Sw. C o n tr o lle d G r o u n d ( T C S ) 209 Purple Park Bra ke W a r n i n g L a m p 210 W hite Power Seat - 6 -W a y - Fore and Down - " a " Body D a r k Blue Y ello w B lac k Stripe LIGHT TRUCK SERVICE MANUAL C o n tr o lle d - Fused Level, I R Va lv e C o n tr o lle d trolled C o n tr o lle d Po w er Seat - 6-W a y - A f t and Up - " A " Body 212 G r o u n d to Belt A s s y Sw. Seat Sen sor to Neutral Sta rt Sw. ( L a m p and Buzzer G rd) 211 Starter Feed L H Seat S enso r C o n tr o lle d INSTRUMENT PANEL AND GAGES 8C-53 E L E C T R IC A L C IR C U IT ID E N T IF IC A T IO N (Cont'd) C ircuit Circuit Number C o lo r 24 8 D a r k Blue C ir cu it N a m e Feed, to A / C C o m p r e ss o r Harn Circuit Circuit Number C o lo r 283 L ight Blue Po wer Seat, Rear V e r t D o w n - 284 Light Green Po wer Seat, A f t M o t o r Motor R e la y C o n tr o lle d 249 D a r k Green Feed, F r o m A / C Harn 250 Brown Feed, Ign. Sw. on Con trolled, F used 251 Ora ng e Passenger Initiator f e e d 252 Y e l lo w G r o u n d , A D L M o d u l e U n lo c k 253 D a rk B r o w n Ground, A D L M o dule Lock 254 Ligh t Green G r o u n d , A D L L T U n l o c k Rela y 285 T an Pow er Seat, Fore M o t o r 286 D a r k Green Po wer Seat, F r o n t V e r t U p - 287 D a r k Blue Po wer Seat, F r o n t V ert D o w n - 288 Y e l lo w - B la c k Po wer Seat, Rear V e r t U p Rela y Motor O u t p u t C o n tr o lle d O u t p u t C o n tr o lle d M otor 28 9 Ligh t BlueB lack Coil 255 Y ellow G r o u n d , A D L R T U n l o c k Rela y 256 D a rk Blue G r o u n d , M o d u l e Controll ed, 257 Brown G r o u n d , A / C Press, Sw. C o n ­ 258 W hite Passenger Initiator R etu rn Hi 259 Purple I R C r a n k Sta rt Sig nal - 260 B lack T h e ft Deterrent - H o o d Sw. 261 Y ellow T heft Deterrent - A la r m A r m T heft Deterrent - K e y - D o o r L ight GreenB lac k Po wer Seat, A f t R ela y 291 D a r k Blue G r o u n d , Heated Gla ss Timer, 292 Ligh t Blue Feed, Heate d Gla ss Timer, 293 Pu rple-White Feed, Heated G la ss T im e r 294 T an D o o r L o c k M o t o r - U n lo c k 295 Gray D o o r Lo ck M o to r - Lock 296 Brown Pow er Seat, Fore Relay 297 Gray Pow er Seat, F r o n t Vert U p R ela y 298 Purple Pow er Seat, F r o n t Vert D o w n 300 O rang e Feed, Ign. Sw., " O n " C o n tr o lle d - 31 8 Y e l lo w - B la c k R e la y A ctiva te d Left Directional L a m p O u t In dicator O n - O f f Sw. C on trolled O n - O f f Sw. C on trolled trolled C o n tr o lle d Level, I R 26 2 L ig h t Green R ela y U n l o c k and A l a r m Disa rm 263 L ight Blue T heft Deterrent - A la r m 264 D a r k Green T h e ft Deterrent - A r m Indication 265 Black-W hite T h e ft Deterrent - A la r m O u t p u t 266 Pink T h e f t Deterrent - A la r m A r m Abort 267 D a rk Green Pw r Seat - Fore and U p Recliner 268 Y e l lo w Pw r Seat - A f t and D o w n 269 L ight Green Pw r Seat - Sol U p and D o w n 270 B l a c k -Y e l lo w Feed, A m p li f i e r to Poten tio m eter 271 Purple 272 L ight Green U n fu se d Stripe 31 9 D a rk GreenWhite Feed, Ign. Sw. O n and C ra n k 340 Orang e Feed, Batt ery - Fused 35 0 Pink-White Feed, Ign. Sw. " O n " C o n tr o lle d - G r o u n d , Poten tio m eter C o n tr o lle d 351 D a rk Blue Feed, Inverter to Op era L a m p Feed, Pot en iom e te r Rh eostat 352 White Pink O p era L a m p to Inverter R etu rn 370 383 L ight Blue C on ve rt C lu tc h Release Sw. to Va c. 38 4 L ight Green Va c. Sw. to T ra n sm iss io n Sw. Sol C o n tr o lle d 274 D a r k Green- C o n tr o ll e d Fused Feed, H d l p Sw . to A m p li fie r, Fused H d lp Sw. C o n tr o lle d 275 W hite Feed, H d lp Sw. to A m p li fi e r 38 5 Purple Hi V a c Sw. to T ra n sm iss io n Sw. Sol L ight Green Feed, N e u t S a f Sta rt Sw. 39 0 T an Feed to Side M a rke r and License 39 4 L ight Green G r o u n d , L T F / D R e m o te H an dle 276 L ight Green Reel. Mtr. Feed, Po w er St. Fwd. 277 Light Blue Reel. Mtr. Feed, Pow er St. Recliner 27 8 W hite A m p li f i e r to Phot oc ell 27 9 B lack H e a d la m p Sw. to Photocell 28 0 Pink Feed, P.M. M o t o r U p C yc le ( D e c k Lid Pull D o w n ) White Y e l lo w Lam p - Export Only B lack Po wer Seat, Rear V ert U p - S w . C o n tr o lle d 395 L ight Blue G r o u n d , R T F / D R e m o te H andle 402 L ight Green Feed, Ele ctro nic Cruise C o n tr o l 403 D a rk Blue Feed, E le ctronic Cruise S h u t - O f f 404 L ight Green E S T P i c k u p Coil to H E I M o du le, Sw. C o n tr o lle d V a lv e G r o u n d , R e la y C oil D o w n C y c le ( D e c k Lid Pull D o w n ) 28 2 Feed, A v I Sw. " P a r k " C o n tr o lle d 281 Lamp P in k - B la c k Recliner Orang e Lamp R ela y A ctiva te d R ig h t D irectional 33 9 Recliner 273 Pow er Seat, Rear V e r t D o w n R ela y 290 Coil Fused 6 Cir. C ir cu it N a m e Valv e Hig h Motor LIGHT TRUCK SERVICE MANUAL 8C-54 INSTRUMENT PANEL AND GAGES E LE C T R IC A L C IR C U IT ID E N T IF IC A T IO N (Cont'd) Circuit Circuit Number C o lo r 405 White Circuit N a m e E S T P ic k u p Coil to H E I M o dule , Circuit Circuit Number C o lo r 465 W hite-Green E S C M o d u le to H E I M o dule , Signal Lead 407 Bl ack E m e r ge n cy Signal Lead, E C M to 408 T an -W hite E C M to E S C By p ass H E I M o d u le Feed, Electric Fuel White Low 406 Da rk Green- C ir c u it N a m e 46 6 Gray I M C to T r i p C om p u ter, R P M Data 46 7 Ligh t Blue L o w Sid e o f Injector " a " IM C b " IM C C o n tr o lle d 468 L ight Green L o w Sid e o f Injector " C o n tr o lle d 410 Yellow E C M to C o o la n t T e m p S enso r 469 B lack-O range M a p Return, L o w Level G r o u n d 411 Light Blue E C M to Fuel Me te ring Sol 470 B lack C o o la n t T e m p and M a n if o l d 412 Purple O 2 Sen sor Sig 413 Tan O 2 Sen sor L o w 471 P in k - B la c k Ba ro Reference Voltage, 5 V T e m p Return, L o w Level G r d 414 Pink O 2 Sen sor Heater High 472 T an M a n if o l d A i r T e m p S ig 415 Ligh t Green E C M to E n r ic h m e n t Sw. 473 B l a c k -L ig h t Baro Return, L o w Level G r o u n d 416 Gray E C M 5 V Reference V o lta ge 417 D a rk Blue E C M to Thro ttle Position Se nso r Blue 474 Gray T hro tt le Posit ion Sensor E xcit ation , 5 V Signal Brown E C M to A d a p tiv e Sw. 475 Pink-White M a p Reference Voltage, 5 V 419 Brow n -W h ite E C M to C h e c k E n g Lp 476 Blac k -P in k T hro tt le P osit ion Senso r 420 Purple E C M to Break Sw. 421 D a rk Blue- E C M to C o ld Start Program 477 Brown M P G R e q ue st Signal 478 Purple Fuel E c o n o m y Indicato r (Grn), 479 L ight Green- Fuel E c o n o m y In dicator (A m b er), 480 O rang e Feed, I M C Batt ery Controll ed, 481 Red Feed, for Injector " a " Fused 418 White M o d ifie r 422 T an-W hite E C M to T C C S o le n o id 42 3 White E S T Signal 42 4 T a n -B la c k E S T By p ass 42 5 Light Blue E C M to I S C - M o t o r E x te n d 42 6 D a r k Blue E C M to I S C - M o t o r Retract 42 7 Pink E C M to I S C -Sw . Return, L o w Level G rd I M C C o n tr o lle d B lac k I M C C o n tr o ll e d Fused 482 W hite Feed, for Injector " Yellow E C M to Canister Purge 483 Green E S C Reference Pulse High 429 Blac k -Pin k E C M to A ir C o n tr o l S o le n o id 484 W hite E S C Reference Pulse L o w 43 0 Purple-White E C M Ref Pulse High 485 B lack E S C Signal E S C D ist rib u t o r G r d 42 8 431 D a rk Green- L ight GreenBlack b " Fused 486 Brown 8 V R ef V o lta ge 49 6 D a r k Blue E S C D e n o t a t i o n Sensor Input E C M to M a p S ig 500 501 Black-W hite Purple M o d u le - P T C , G r o u n d Plane Sensor, S e c o n d a r y P T C Sensor, P r im a ry P T C 432 D a r k BlueGray 43 3 G r a y - B la c k E C M to Baro S ig 502 Gray 43 4 O r a n g e -B la ck E C M to Neutral Park S w 503 Orange 43 6 Brown E C M to A i r S w itch S o le n o id 504 G l o w Plug, Feed or S enso r Br o w n -W h ite Feed, V o lta g e R e gu la to r C on trol 43 7 Brown E C M to Ve hicle Speed Sensor 438 Red-White E C M to H ig h G ear S w itch 50 5 Y e l lo w 439 P in k - B la c k Feed Ign. Sw. " O n & C r a n k " (D i o d e Isolated) Feed, G l o w Plu g R ela y 50 6 Light Blue Return, G l o w Plug R e la y C o n tr o lle d - Fused 507 D a r k Blue W ait L a m p 508 Y e l lo w S w it c h e d G r d for "W ater-in- 50 9 T a n k " In dica to r O r a ng e-B la ck G l o w Plug, Feed or Sense, 610 Tan Pow er Seat - 6 -W a y - Fore and Light Blue Po w er Seat - 6 -W a y - A f t and Up, 440 Orange Feed, Ba ttery - Fused 450 Black-W hite C L C C E C M Power G rd 451 W h it e-Bla c k D ia g n o s tic Enable 45 2 B lack L o w Level G r o u n d 45 3 B la c k -R e d E S T R ef Pulse L o w Passenger Sid e D o w n R e la y to M o t o r 45 4 Bl ack-W hite Critical G r o u n d Circuit 460 Black -Ora nge Feed, Ba ttery Cir cu it Breaker 611 461 Orang e Protected I M C to E C C , Serial Data for M P G or 618 46 2 Pin k -B la c k G r o u n d , I M C , Set T i m i n g 666 R e la y to M o t o r Y e l lo w -B la c k Feed, Lt Sid e Trailer and Direction Green-White Feed, R t Sid e Trailer and Direction D a r k Blue W d o C o n t r o l R f U p - Passenger Sw. 463 Black-O range I M C to T rip C o m p u t e r Signal, Fuel 667 Brown W d o C o n tr o l R f D o w n - Passenger Sw, F l o w Da ta (Injector on T im e) 66 8 D a r k Blue W d o C o n t r o l Lr U p - Lr Sw. Di agnostics 464 T a n -B la c k LIGHT TRUCK SERVICE MANUAL M P G Reset Signal 619 INSTRUMENT PANEL AND GAGES 8C-55 E L E C T R IC A L C IR C U IT ID E N T IF IC A T IO N (Cont'd) C ir cu it Cir cu it Number C ir c u it N a m e C o lo r 669 Brown W d o C o n tr o l Lr D o w n - Lr Sw. 670 D a r k Blue W d o C o n tr o l R R U p - R R Sw. 671 Brown W d o C o n tr o l R R D o w n - R R Sw. 756 D a r k Green- Feed, V a c S o l C o n tr o lle d (F or W hite Circuit Circuit Number C o lo r 815 B lack Trigger O u t p u t Controll ed, Fused 817 T an Accelerator E n r ic h m e n t In pu t #1 81 8 Ligh t Green A cc elera tor E n r ic h m e n t Sw. 819 Black-W hite Clo ss ed T h ro tt le Sw. C on troll ed, Fusible L i n k 820 Orang e W id e O p e n T h ro ttle S w itch Protected 821 D a r k Green G r o u n d , E F I M o d u le C o o la n t Ele ctro nic Distrib utor) 801 80 4 Purple Feed, E F I , Ign. Sw. " C r a n k " S u p p l y V o lta ge Fusible L i n k Protected 80 7 Purple Feed, E F I Batt ery Con troll ed, Fused 80 8 D a r k Blue Feed, E F I M o d u le Fast Idle Valv e O u t p u t and 3 C ir c u it C o n ­ T e m p . Sen sor O u t p u t C o n ­ trolled 822 D a r k Blue G r o u n d Resistive, C o o la n t 82 3 Gray G r o u n d , E F I M o d u l e A ir T em p . 82 4 O range G r o u n d , Resistive A i r Temp. 827 D a rk Green Feed, E F I M o d u l e Elec Fuel T em p . Sen so r C o n troll ed trolled - Fused 810 Tan Feed, D istrib u to r Electronics 811 White Feed, E F I M o d u l e G r o u p T w o S en so r O u t p u t C o n troll ed C o n tr o lle d S en so r C o n tr o lle d Injector O u t p u t C o n troll ed Fusible L i n k Protected P u m p O u t p u t C on trolled - Feed, E F I M o d u l e G r o u p On e Fused Injector O u t p u t C on trolled Fusib le L i n k Protected 813 W hite 828 Gray Feed, E F I , Ign. Sw. " O n & 831 Brown Feed, E F I M o d u l e E G R C r a n k " C o n tr o lle d Fused Feed, E F I D ist rib u t o r Trigger and 8 1 5 C ir c u it C ontr oll ed, S o le n o i d O u t p u t Con troll ed, Fused 814 Y ellow A cc elera tor E n r ic h m e n t In p u t # 2 Pink Feed, E F I Batt ery Controll ed, Pink Feed, E F I M o d u l e D istrib utor 816 Brown 812 C ir cu it N a m e Fused Feed, E F I D ist rib u t o r Trigger and 8 1 5 C ir c u it C ontr oll ed, Fused THE CIRCUITS LISTED BELOW HAVE REVISED COLORS: CIRCUIT ORIGINAL COLOR REVISED COLOR 422 TAN-WHITE TAN-BLACK 432 DARK BLUE -GRAY LIGHT GREEN 438 RED-WHITE DARK GREEN-WHITE 508 YELLOW YELLOW-BLACK LIGHT TRUCK SERVICE MANUAL 8C-56 INSTRUMENT PANEL AND GAGES Fig. 8C-44--CK Series W iring 1 of 31 LIGHT TRUCK SERVICE MANUAL INSTRUMENT PANEL AND GAGES ------ 8C-57 -------- I DK GRN - 29A -------------- 8 BRN 9A---------------5 DK BUU I5A ---------- I LT GRN-I1A-----------------5 LT BLU-I4A------------ Fig. 8C-45--CK Series W iring 2 of 31 LIGHT TRUCK SERVICE MANUAL 8C-58 INSTRUMENT PANEL AND GAGES Fig. 8C-46--CK Series W iring 3 of 31 LIGHT TRUCK SERVICE MANUAL INSTRUMENT PANEL AND GAGES 8C-59 pimk-3CkH x O - Fig. 8C-47--CK Series W iring 4 of 31 LIGHT TRUCK SERVICE MANUAL 8C-60 INSTRUMENT PANEL AND GAGES 8 YE L-237-----SEAT BELT B2R-237 SDK BLU- 15B----- BULK HD CONN-15 5 LT BLU -14B---- BULK HD CONN-14 6 BLK-T50G----- SPLICE 150 5 PNK/BLK-39G - - - SPLICE 39 5 TAN-31 — -BULK HD CONN-31 0 PNK/BLK-39E- — SPLICE 39 BLK- 150H----- SPLICE 150 5 PNK-30B-------------------------------------- 5 PNK-30A----- BULK HD CONN-30 5 TAN/WHT -33A-----BULK HD CONN-33 5 TAN/WHT-33C — PARK BK WARN SW .5 PNK/BLK-39F----- SPLICE 39 -----------------------.8 DK BLU-931 — BULK HD CONN-931 GUAGE. CLUSTER WITH IACHOMFTER 2965164 - .8 B L K -1 5 0 ----- " - . 8 WHT-12KHDT)- Tr—.5 ACHORN-140— O g| A B q CLOCK ___ _ I 2 9 65961-^ r .8 PNK/BLK-139— ^ ----------------------------------------j— .5 BLK-150 —- 1 -5 TAN WHT-33B - 5 DK GRN - 35A LT G RN-24 — - g DK BLU-75 - 8 P N K -94-----------.8 BLK-150E---------.8 PPL-9 2 ------------ 8 GRY-91-------------.8 BLK/LT BLU-97-.8 LT GRN-2 4 ------- Fig. 8C-48--CK Series W iring 5 of 31 LIGHT TRUCK SERVICE MANUAL INSTRUMENT PANEL AND GAGES 8C-61 -2984369 TERM Fig. 8C-49--CK Series W iring 6 of 31 LIGHT TRUCK SERVICE MANUAL 8C-62 INSTRUMENT PANEL AND GAGES Fig. 8C-50--CK Series W iring 7 of 31 LIGHT TRUCK SERVICE MANUAL INSTRUMENT PANEL AND GAGES 8C-63 628 8585 -8 -8 BR N -9 LT GRN-24 - 6 DK GRN-19 - 6 YEL-18 BULKHEAD CONN B/U LP y -0 9 1 7 2 3 4 TAIL STOP 4. DIR LAMP CAB.CREW-CAB CHASSIS Fig. 8 C -5 T -C K Series W iring 8 of 31 LIGHT TRUCK SERVICE MANUAL 8C-64 INSTRUMENT PANEL AND GAGES -£ SPLICE 150 BLK-I50DSHEET METAL GRO 6294015 SOCKET- BRN -96 TAIL STOP DIR SIDE M K R t tytl LAMP -8 BLK-I50C BRN- A — 9 SPLCE 9- -.8 YEL-18 -.8 8LK-I50A -.8 LT G RN -24 -.8 BLK-I50B 8 9 1 1 0 2 7 SOCKET- /''BLU OR A - J PPL OR V LT GRN r - 2977720 SPLICE-19-i -SPLICE-9 FRAME GRD - 8 DK GRN-l9iA-> - 8 BRN-9A "8 YEL-18 r -.8 PNK-30(HDT) EXT WIRE WHEN USED \ -.8 BRN-9C---- ( x ) ( l }-| .8 BU L S ) -SPLICED LIC LAMP FUEL METER TANK UNIT ------------------------- £ q ) 6C^6PM <-30(H XUa a n » n ----------- A — M U in 8911027 SOCKET - 8 B L K - I5 0 B - 8 LT GRN- 24 TAIL STOP DIR S ID E MKR& LAMP — .8 BLK-I50A *-^8 t8 YEL-18 YEL-8 BRN-9A - SPLICE 9- — :8 B L K -I5 0C 8 B R N -9 B — 6294015 SOCKET JL SPLICE 150- .8 BLK-I50D SHEET METAL GRD SUBURBAN Fig. 8C-52--CK Series W iring 9 of 31 LIGHT TRUCK SERVICE MANUAL INSTRUMENT PANEL AND GAGES R EF BODY H AR N ESSRPO M V4 LT G R N 3 8 4 B — -1 top89l7583 m< 00 Z2 cc o cr o 00 rO rO RPO CE N G IN E ) M V4 TRA N SM ISSIO N Fig. 8C-53--CK Series W iring 10 of 31 RPO MV4 TRANSM ISSION FOR RPO N A 5 /L G 9 /L S9 8C-65 8C -66 INSTRUMENT PANEL AND GAGES j— 8900444 2989557 GROMMET 06 ONLY CHANNEL-A FOR 06 S 16 RIGHT RR SPKR 8900444- CHANNEL-B FOR 03 RIGHT RR SPKR 1 2 0 0 4 5 4 5 —7 .8DK B L U - 4 6 ---------- 1/ ;8 L T B L L H ' ' 8 Y E L - 1 16 8 B R IM -1 9 9 s; -.8TAN-2 01 .8 GRA-118 — rTO .80KGRN-I 17-HT -8L.T GRN-200— / 12004544 e -1 2 0 0 4 5 4 5 -.8 DK BLU -4 6 J - 8 L T BLU -115- M F (jr -.8YEL-43- ___ -.8BLK-I50 — -.8GRA-8------------ 8900444- -.8 BRN-199 — .8 YE L-H 6 ■ CHANNEL-A FOR 03 LEFT RR SPKR ') U80 R E A R SPEAKER LEFT SIDE (16) ---.5 YEL-43-H43lKh U --fi B L K -1 5 0 - J V 12004543 -----4 - B G R A H ie - .8 T A N -201F R O N T SP K R . ("r a d i o e q u i p m e n t RPO. U 63-U693U80 Fig. 8C-54--CK Series W iring 11 of 31 i IP 'jrr , S F R W .S MANUAL INSTRUMENT PANEL AND GAGES 8C-67 Fig. 8C-55--CK Series W iring 12 of 31 LIGHT TRUCK SERVICE MANUAL 8C-68 INSTRUMENT PANEL AND GAGES MARKER LAMP-FRONT LEFT Fig. 8C-56--CK Series W iring 13 of 31 LIGHT TRUCK SERVICE MANUAL INSTRUMENT PANEL AND GAGES 8C-69 -.8 Y E L - 5 0 8 ( H W ) - . 8 P N K - 3 0 IH W ) FUEL TANKS RPO NL2 WITH RPO LF9 8917102 (ATTACHES TO FUSE BLOC ---------- .8 PNK/BLK-39C INST CLUSTER CONN-237----------- .8 Y E L -2 3 7 -------------------(SEAT BELT WARNING LAMP) ® SPLICE 150---------------— • ---------------- .8 (GROUNO; B L K -I5 0 J -------- EXTENDED --------- ----------□ RETRACTED E 5 8 ] ------------- .8 BL K -2 3 8------X ' V _ 29 8 4 I6 3 SEAT BELT RETRACTOR SW 6294051 E X IS T IN G IN ST R U M E N T PANEL W IRIN G H A RNESS .8 GRA - 8.8 O R N - 4 0 SEAT BELT AND LIGHT MINDER AURAL WARNING MODULE NOTE: BASE SEAT BELT WARNING BUZZER AND TIMER IS NOT INSTALLED. 12004962 -120 0 4 6 9 0 FUSE BLOCK HEADLAMPWARNING BUZZER RPO T 63 Fig. 8C-57--CK Series W iring 14 of 31 LIGHT TRUCK SERVICE MANUAL 8C-70 INSTRUMENT PANEL AND GAGES S ID E M A R K E R L A M P R E A R -S T O P & .D IR E C T IO A L L A M P BACK U P LA M P BACK U P LAM P R E A R -ST O P & D IR E C T IO A L L A M P S ID E M A R K E R L A M P ----------- BCSTER T AIL,ST O P, + D IR SIG N A L L IG H T S 8900444 i DK B L U -4 6 ^ " i L T B L U -1 1 5 % . -.8 -.8 -B -.8 LT B L U - II5 D K B L U -4 6 T A N -2 0 1 G R A - I 18 -------- .8 G R A - 8 7J 1 K J H D p CENTER SPEAKER R IG H T T A N -2 0 1 A :0 G R A -I I 8 A - I°H jC! •cr' ---- - S T A N -201 A - . 8 G R A -I I 8 A - ;cJ. If-J I s ji'" ! M ------------. 8 Y E L - 4 3 -----------.8 B L K - 1 5 0 - P y M d CB Fig. 8C-58--CK Series W iring 15 of 31 LIGHT TRUCK SERVICE MANUAL REAR SPK R . R P O U .8 0 12004545 - . 8 T A N - 2 0 IB J L - . 8 G R A -I I S B K H £ 11 5 -------- .8 Y E L - 4 3 - H T -------- -.8 B L K -1 5 0 \ R A D IO W IT H 12004543 - ^ 8 0 R E A R S P K R . irzf I 46 R A D I O E Q U IP M E N T RPO U P 5 - U 8 0 INSTRUMENT PANEL AND GAGES 8C-71 Fig. 8C-59--CK Series W iring 16 of 31 LIGHT TRUCK SERVICE MANUAL 8C-72 INSTRUMENT PANEL AND GAGES LEFT FRONT DOOR LOCK MOTOR Fig. 8C-60--CK Series W iring 17 of 31 I IGHT TRUCK SERVICE MANUAL INSTRUMENT PANEL AND GAGES 8C-73 Fig. 8C-61--CK Series Wiring 18 of 31 LIGHT TRUCK SERVICE MANUAL 8C-74 INSTRUMENT PANEL AND GAGES BLOWER MOTOR (REAR) AIR CONDITIONING RPO C-69 EVAPORATOR PRESSURE CONTROL SW I■ »■ Li T U NOTE: * I. USE WITH 12010191 RETAINER FUSED FEED FROM IGN 3 __« --T V SELECTOR SWITCH AIR CONDITIONING R P 0 C -6 0 Fig. 8C-62--CK Series W iring 19 of 31 LIGHT TRUCK SERVICE MANUAL IN S T R U M E N T P A N EL A N D G A G E S 8 C -7 5 Fig. 8C-63--CK Series W iring 20 of 31 LIGHT TRUCK SERVICE MANUAL 8C-76 INSTRUMENT PANEL AND GAGES Fig. 8C-64--CK Series Wiring 21 of 31 LIGHT TRUCK SERVICE MANUAL INSTRUMENT PANEL AND GAGES 8C-77 J U N C T IO N B L O C K C A M P E R E Q U IP M E N T R P O -U Y I Fig. 8C-65--CK Series W iring 22 of 31 LIGHT TRUCK SERVICE MANUAL 8C-78 INSTRUMENT PANEL AND GAGES Fig. 8C-66--CK Series W iring 23 of 31 LIGHT TRUCK SERVICE MANUAL INSTRUMENT PANEL AND GAGES & B/U L A M P 8C-79 & B/U L A M P FLEETStDE PICKUP RPO. E63 TAIL & STOP & DIR SIG-SI MKR i. B/U LAMP TAIL & STOP 4 DIR SIG-SI MKR & B/U LAMP STEPSIDE PICKUP RPO E62 Fig. 8C-67--CK Series W iring 24 of 31 LIGHT TRUCK SERVICE MANUAL 8C-80 INSTRUMENT PANEL AND GAGES ---------------- . 8 P N K - 9 4 ------ ' I ---------------- -.8 B L K - 1 5 0 -------1 ---------------- -.8 P P L - 9 2 ------------ J I -------------8 G R A - 9 1 — --------------- J I . ---------------- -.8 B L K / L T B L U - 9 7 ------1 | ---------------- . 5 G R A - 8 ---------------- -------- 1 IN S T P N L W R G HARN PULSE WIPER SYSTEM R.P.O. CD4 H E A V Y D U T Y T R A IL E R R P O UY7 Fig. 8C-68--CK Series W iring 25 of 31 LIGHT TRUCK SERVICE MANUAL INSTRUMENT PANEL AND GAGES R X . DOOR LOCK SW L.H. D O O R LH DOOR 8C-81 LOCK PM MOTOR FU SE - p e rm an e n t m agnet PO W ER DOOR L O C K S 12 D O O R ) R .P Q A U 3 BLOCK 6394742 r— 2 B L K - I5 0 A ■O 166Q FU U T r *-----1—1b=i 1 R|,’h' / H WINDOW R H SWITCH a y i BU S BAR G RD L H WINDOW SWITCH 2 B L K - I5 0 B MTR BKT G RD g )— — M T R BKT G R D 2 B L K -1 5 0 L— 2 D K B L U / W H T -1 6 6 2 T A N - 167 — 3 P N K -7 0 - 2 B L K -1 5 0 — ® 3 PNK-70 — — ------2 T W -I6 7 A ------------ 2 D K B L U / W H T - I6 6 A - L-2 TANH67B(HDT| L - 2 D K BLU W H T-66B- (HDT) AUTO BESET 8917486 FUSE BLOCK L H MOTOR M W E P W IN D O W (■/ ^O O R R.P.O. A 3 Fig. 8C-69--CK Series W iring 26 of 31 LIGHT TRUCK SERVICE MANUAL 8C-82 INSTRUMENT PANEL AND GAGES LOCK 1 9 LH DOOR I LOCK SW M --- £^*“12004155 I2 R H LH c"CUT*» — ^ W IN D O W M O T O R W IN D O W M O T O R POWER WINDOW & LOCKS RPO A3I & AU3 (2 DOOR) Fig. 8C-70--CK Series W iring 27 of 31 LIGHT TRUCK SERVICE MANUAL INSTRUMENT PANEL AND GAGES 8C-83 RT SIDE M ARKER 6294015 SOC .5 DK 8 L U -I5 B .5 BRN-9F ----.8 B L K -I5 IB ---- w ---- .8 B L K - I5 IA --------j 0 RT HAND HIGH & LOW BEAM <6 SHEET METAL TAL X GROUND FRAME GROUND J - .8 B LK-I5IC I LT G R N -IIG .8 TAN-I2C — .8 DK BLU H 5C .8 B R N -9 G -----.8 B L K - I5 IF - .8 B L K - I5 IE - 7 I LT G R N -IIF - 12004267 RT HAND HIGH BEAM TO RT HAND HORN i (J C\J i 12004267 p CO UJ CTI a CD 00 TO LT HAND HORN LT HAND HIGH BEAM .8 B L K -I5 0 A — .8 B LK-I50C I LT GRN-I IB .8 L T B L U -I4 C .8 B R N - 9 C ---.8 B L K -I5 0 E .8 B L K -I5 0 B I LT G R N -1 1C 1 I DK G R N -2 9 A •5DK B L U -I5 A .5 LT B L U - I4 A — I LT G R N - I I A - j-.8 PNK-94--------- oJ-,8 W H T -9 3 ----------- -.8WHT-39A -.8 PPL-92 - W - .8 P P L - 9 2 ------------- -3PNK-3A H --.8G RA-9I— r----■8917544 i W iPER MOTOR 1 I 0RN-240A I 0RN-240B -I DKGRN-29— .5 BLK-28- •3 BRNMB 2984164 HORN R ELAY 3 BRN-4A■3RED-2A-----,5 TAM/WHT-33A .5 B R N -2 5 -----.5 2 -2 -2 -1 -.5 -.5 -3 2973407 OK GRN-35ALT 6LU-72 — ORN-52-----YEL 51-----0RN-I40---DKBLU-I5B TAN-3 1----RED-2F----- BACK UP 9W M AN U AL TRANS .5 BLK-28---.5 LT BLUH4A-5LT BLU-I4B -5DK BLU-I5A -.5DKBLU I5B.8BRN-27----.8 PPL-16----.8YEL-I8----.8 DKGRN-19.8 WHT-17----- 8911921 NEUT START i BACK UP SW AU T O -TR AN S 1200414 7- * — .8 OK BLU — .8 BRN---- . 8 PPL — — .8 Y E L ---— .8 DK GRN — .8 WHT----12004148 & GRA-8 ------- .8 PPL-16--------.8 ORN - I40A---.8 WHT-93-----.8 PNK/6LK-39F - 3 BRN-4A-;---- y rOfNj CLUTCH START SW |M^0 K IO C D N SW ------------ 3 PPL* 6 ------------------8PNK/BLK-I39 .22 BRfVWHT-130- -3 BRN-4 B -----.8 0RN/WHT-24I ;8BRrVWHT-24l — 3 RED-2E1— i — 3RED-2A -------3RED-2B— 'j / ^ - N O T E : w ir e 130 IS A K> OHM RESISTANCE WIRE FUSE BLOCK ■--120)0082 -Z> PNK/BLK-39C-TO SPLICE 39 -.8 PNK/BLK-09--'.8 ORN-4 0 ------ — 3 P N K -3 A - ------ 3PNK-3B/— 3RED-2C- 12004868REf GAUGE CIRCUIT -12004890 :5 TAN -31-------.5 DK GRN-35A r5 BRN-25-------.8 FNK/BLK -39F -1 DKGRN-44;8PPL-I6----- -12010327 lBULK'HD.CONN.1 ------ -.5 TAN/WHT-33A p.5 DK BLU-15 A---------- 1 LT GRWIA---------- .5 LT BLU-(4 A ---I-------.8 TAN-12---------1 LTGRN;8TAN — -1 DKGRN-29 -.5 LT GRN-II B 2,1,164 IdlMMERSWl -£ BRN-9A — Fig. 8C-78--G Series W iring 4 of 20 LIGHT TRUCK SERVICE MANUAL .8 DK BLU-38—* -3 R E D -2 B ---------.8 YEL-18 ---------1 0RN-240B-----.8 DK GRN-19-----.8 LT GRN-24-----.8 DK BUJ-75 -----.8 BLK/LT BLU-97 -.8 PN K-94 --------.8 P P L -9 2 ----.8 GRA-91 --------.5 LT GRN-IIB--.8 BRN-9A — ------ I YEL-10---------.8 ORN- 4 0 -------- INSTRUMENT PANEL AND GAGES - £ TAN/W HT-3JC- -dT ' 8 C -9 1 2904SM TERM-7 NOTE: THE WIRE ASSEMBLY WITH C H J WIRES 156A.I56B « 156C -----1— IS NOT USED WHEN THE POWER WINOOW OR POWER DOOR LOCK,OR COMBINED POWER WINOOW » DOOR LOCK HARNESS IS USED AS THEY ARE PART OF THESE HARNESSES REF RPO AU3-A3I COMBINED ,— 3 WHT*-L .8 B L K /W H T - 9 IA - J 8917544 - .5 DK BLU-9 4 .5 BIK-I50 -------.5 LT BLU-92 -.5 BLK/WHT- 91 -.5 BLK/LTBLU-9/ -.5 GRA-8 / 8917540'— ' WIPER MOTOR T PULSE WIPER/WASHER CONTROL PULSE WIPER CONTROL MODULE MOM REF l/P B+ACC FUSED-------- .8 WHT-93J GROUND--------------- .8 BLKH50C—t HARNESS IP S DIM CKT--------.5 GRA-8E L j3 PNK— - = ;^ L PK Lz z r T i i i -------------J | I | 1--------- .8 BLK/LT BLU-------- -1 I L------------ .5 G RA-8B---------------- 1 PULSE WIPER SYSTEM R.P0.-CD4 8 BLK-I50(HW> 89 0 5426 3BRIVW HT-50 3 WHT-952A 890 5 4 2 6 2 LT BLU-72 2 rEL-51 2984092 2989576 GROMMET BUS BAR GRD AUXILIARY HEATER EQUIPTMENT RRO.C-36 Fig. 8C-85--G Series Wiring 11 of 20 LIGHT TRUCK SERVICE MANUAL 8C-98 INSTRUMENT PANEL AND GAGES Fig. 8C-86--G Series Wiring 12 of 20 LIGHT TRUCK SERVICE MANUAL INSTRUMENT PANEL AND GAGES 8C-99 KEY SWITCH ASM Fig. 8C-87--G Series Wiring 13 of 20 LIGHT TRUCK SERVICE MANUAL 8C -100 INSTRUMENT PANEL AND GAGES LEFT FRJ SPK R CHANNEL-A Fig. 8C-88--G Series Wiring 14 of 20 LIGHT TRUCK SERVICE MANUAL INSTRUMENT PANEL AND GAGES 8C -101 •1 PINK-76B — — -2 P N K - 7 6 --------------■ I T A N - 167 ------------' 1 DK BLU/W HT-166 ---- 2 B L K - 1 5 0 -------------- 167176 k isjj- -1 TAN* 167-------------1 DK BLU/WHT-166-2 BLK- 150------------- 166 1252240 CIRCUIT BKR 30 AMP AUTO RESET 2 - PLACES A * \ , /-I20 0 40 29 r 12004267 “1 fa5! fs X2o CIRCUIT "—0+\ — T~° ' u BAT CIRCUIT i ^ 12 0 0 4 8 8 9 - . ' S■ b LEFT INDOW i___ u BUS BAR GROUND LH WINDOW SW FUSE BLOCK 12004155 UP £ DN-LOCK LH DOOR LOCK SW -.8 BLK/WHT -194 - 2 0 R N /B L K -6 0 -.8 LT BLU-195 — - 8905205 SPLICE-6 0 194 60 195 194 60 -2 0RN/BLK-60B 2 0RN/BLK-60C 194 60 195 667 1 *uro«»tT T "1 0J \2s 194 8 BLK/WHT-194 6 0 3-2 0 R N /B L K -6 0 195 - . 8 LT BLU-195 RH WINDOW MOTOR UP-U :h POS, 2NEG=UP RH DOOR LOCK SW pfyj LH WINDOW MOTOR ___ _ , | COCUIT •*« _ T M L c D-I »UTO KCSET CIRCUIT BKR AUTORESET POS. 2NEG- UNLOCK P M -1 GRA-295 C • POS,. 2NEG-UNLOCK PM -1 TAN-294C- RH DOOR LOCK MOTOR - 8 BLK WHT-194 A- LH DOOR LOCK MOTOR — 1 T A N -2 9 4 ------ -r6 LT BLU-195A DOOR LOCK RELAY -2977373 I G R A-295- -1 TAN 294E -------------E S I -1 GRA 295E -- ------- (295 BODY HARNESS DOME LP WIRE CONTACT SW NOTE: PM = PERMANENT MAGNET -.8 W HT-156BINSTRUMENT PANEL HARNESS DOME LP SW WIRE RT DOOR JAMB SW POWER WINDOWS R.RO. A31 9 POWER DOOR LOCKS R.R0.AU3 Fig. 8C-89--G Series Wiring 15 of 20 LIGHT TRUCK SERVICE MANUAL 8C -102 INSTRUMENT PANEL AND GAGES CONTROL /—120 r MODIFIER CONTROL COLD START MODIFIER RPO B5H L.H. STEPWELL LAMP R.H. STEPWELL LAMP 2973324 TERM BODY HARN FOREWARD BODY~_I~_7 W R G _______, HARN---------- / I AUX LIGHTING R.RO. TR9 STEPWELL & READING LAMP Fig. 8C-90--G Series Wiring 16 of 20 LIGHT TRUCK SERVICE MANUAL INSTRUMENT PANEL AND GAGES 8 C -103 8905206 ■-19 w9; TO i 5 5 L !e -01^ 116 - . 8 C H AN NE L-B (" I E ) — DK BLU -'R EA R LT BLU —(Rt AR BRN------- (RFAh — >PL--------(RFAR h - 8 DK BLU-46 .8 LT BLU-115 .8DKGRN-I17ggg y —£LT GRN200 B R N -199 YEL-H6 FEEDi RE TURN) FEED! RETURN! -SPLICE TO BODY BUILDER WIRING CUTAWAY L V AN G 300(03) (32) FOR 03 4 32 RIGHT FRT SPKR. :8 DK BLU-4 n 8 L T BLU-II 120045457 .8 DK BLU-46—— .8 LT BLUH I5~ p _L — .8 YEL-II6—MJ< — .8 BRN-199— .8TAN-20T — .8GRA-118—r . .8 DK GRN-117—1 3 LT GRN-200-----.8 GRA-8 RIGHT RR.SPKR. M. - .8 YEL-43 -.8 BLK-150 12004543 RADIO RCVR. I lispl— '.a BLK-150- \7 3l <8"4|' {6___5| —12004267 BUS BAR GROUND LEFT FRT SPKR. 8905220# - . 8 DK BLU-46 r .8 L T BLU-115 .8 BRN-199 - . 8 YEL-II6 LEFT RR. SPKR. T * 8 9 117 7 3 ^ ^—8911772 RADIO EQUIPMENT R.PO. UM 2-U58-U N3 Fig. 8C-91--G Series Wiring 17 of 20 LIGHT TRUCK SERVICE MANUAL 8C -104 INSTRUMENT PANEL AND GAGES REF BODY WIRING . HARNESS RIGHT SIDE 5 BRN-9------------- r e f r ig h t .5 DK GRN-19----- REAR LAMP WIRE ASM 5 LT GRN-24------ TO TRAILER REF BODY WIRING HARNESS LEFT SIDE BR N-9C----- -.5 BR N -9A ------ Y EL-18------- 8 YEL-I8A------ -.5 DK G R N -I9- LT GRN-24- ------ .8 LT GRN-24-------^ •5 LT GRN-24- REF REAR LAMP WIRE ASM BRN-9-------- [LIGHT DUTY TRAILER WIRINfc RPO U89 REF RIGHT REAR LAMP WIRE ASM BATTERY CIRCUIT REF BODY WRG HARNESS LEFT SIDE .8 BRN-9C — '3- .8 YEL-18 — LT GRN-24C— 298467$—' .8 Y E L -I8 A - WF— .8 LT GRN-24 .8 BRN-9 — Fig. 8C-92--G Series Wiring 18 of 20 LIGHT TRUCK SERVICE MANUAL -5 BRN-9A---------- oi gi —.5 DK GRN-19 5 LT GRN-24------- J 2984378 REF LEFT REAR LAMP WIRE ASM ______ HEAVY DUTY TRAILER WIRING RPO U Y 7 INSTRUMENT PANEL AND GAGES 8C-105 Fig. 8C-93--G Series Wiring 19 of 20 LIGHT TRUCK SERVICE MANUAL 8C-106 INSTRUMENT PANEL AND GAGES Fig. 8C-94--G Series Wiring 20 of 20 LIGHT TRUCK SERVICE MANUAL INSTRUMENT PANEL AND GAGES 8 C -107 PROVISIONS FOR SIDE MARKER LP DASH HIGH - LOW BEAM Fig. 8C-95--P Series Wiring 1 of 9 LIGHT TRUCK SERVICE MANUAL 8C-108 INSTRUMENT PANEL AND GAGES Fig. 8C-96--P Series Wiring 2 of 9 ' IGHT TRUCK SERVICE MANUAL INSTRUMENT PANEL AND GAGES 8 C -109 PROVISIONS FOR SIDE MARKER LP 6294125 SOCKET WIRE SIZE CONVERSION TABLE METRIC SIZE m rr\2 AWG SIZE .22 .5 .8 1 2 3 5 8 13 19 32 40 24 20 18 16 14 12 10 8 6 4 2 1 -S 8BLK-151- ☆ BRN - 9 G ---------TO SHEET METAL PROVISIONS FOR BACK UP LP PROVISIONS FOR TAIL-STOP&DIR LP trim 03 CD 0 BRN-9E(HOT) c D SPLICE 9 PROVISIONS FOR LIC PLT LP TWO PLACES 10RN-240B------- §5 PROVISIONS FOR , 8W HT. 1 5 6 ^ , DOME LAMP 2965901 .8 BRN-9C (HOT) (K SPLICE 9 111 OQtpCD PROVISIONS FOR TAIL-STOP 8 DIR LP -.8 BRN-9B(HDTI-.8 BRN-9AIHDT) .6 LT GRN-2481HDTI LTGRN-24AIH0T) jW —.6 DKGRN-191HDT) PROVISIONS FOR BACK UP LP -.8 Y E L-18(HOT) ----.8BRN-9K 6294125 SOCKET SBLK-150- TO SHEET METAL -2 -2 -2 -2 PROVISIONS FOR SIDE MARKER LP BR N -9 — YEL-18 — DK GRN-19 LT GRN-24 Fig. 8C-97--P Series Wiring 3 of 9 LIGHT TRUCK SERVICE MANUAL 8 C -1 10 INSTRUMENT PANEL AND GAGES FRAME GRD (S>-50GRD STRAP FPAME GRD V W ’' neut \-Z '/ START NEUT START C BACK UP SW START OfF-LOCK Fig. 8C-98--P Series Wiring 4 of 9 LIGHT TRUCK SERVICE MANUAL INSTRUMENT PANEL AND GAGES 8C-111 / /F R O N T \ VOF DASH/ N OTE rHE GROUND LEADS PROVIDED IN Al I ELECTRICAL WIRING MUST BE TERMINATED IN A MANNER TO INSURE A COMPLETE UNIFORM A. ONTINUOUSVEHICIE ELECTRICA1 GROUND CIRCUIT. START O FF-LO CK Fig. 8C-99--P Series Wiring 5 of 9 LIGHT TRUCK SERVICE MANUAL 8 C -112 INSTRUMENT PANEL AND GAGES SIDE MARKER LAMP RPO E32 AND E33 ONLY RPO B3M BATTERY fu sib le lin k - 13RED-2B(GPT)--------------------------------------RPO B3K TEMP SENDER YS 2962965 SEE NOTE 1 — 2 BRN-9(GPT) — •2YEL-18(GPT) — ----- 2 DK GRN-I9(GPT) 2LT GRN-24CGPT) - HIGH - LOW BEAM SIDE MARKER LAMP RPO E32 AND E33 ONLY Fig. 8C-100--P Series Wiring 6 of 9 JGHT TRUCK SERVICE MANUAL INSTRUMENT PANEL AND GAGES 8 C -1 13 8905381 SOCKET U W S WIPER u MOTOR .0 GRA-91----- 917319 I W/S WIPER WASHER SW M40 KICKDOWN SW 2973407- -2984164 HORN RELAY STOP LPSW \ 2984235 8911781 G RO MM ET 0911781 G R O M M E T 12010094 "T2004962 FUSE BLOCK ■3 RED-2C 5PLICE-4- .8 DK BLU- 3 8 J L.8 DK BLU-75 .8 P N K /B L K -1 3 9 -------— ------------ SPLICE 3 - ^ -.5 DKBLU-15A 1 BRN-9A — 1 LT GRN - 24 8900855 DIMMER SW 100 AMP JUNCTION BLOCK Fig. 8C-101--P Series Wiring 7 of 9 LIGHT TRUCK SERVICE MANUAL 8 C -1 14 INSTRUMENT PANEL AND GAGES PROVISIONS FOR DOME LAMP NOTE I WIRES 9 ,1 8 ,1 9 +2 4 IN TAIL LT EXTENTION ARE FOR P 1 0 0 . -2BRN -9(t3PT)-------2Y EL-I8(G P T)------ - -2DKGRN-*9(GPT)-2 LT GRN-24(GPT)- Fig. 8C-102--P Series Wiring 8 of 9 LIGHT TRUCK SERVICE MANUAL INSTRUMENT PANEL AND GAGES 8C -1 15 SIDE MARKER LAMP RPO E32 AND E33 ONLY B/U LAMP RPO E32 AND E33 ONLY ^rSPLICE-9 2977107 >-.8 BRN -9C(HD T)— 0 ~ ) .8 BRN-9B(G PT)- p i o (t :' =:^ - . 8 P N K -3 0 (H X L )— (EjOQ B R N -9A (H D T)B R N -9A (G P T)-P 100 -.8 BRN- 9 B (H D T).8 B R N -9 K (G P T )-P 1 0 0 8 LT G RN-24B(HD T)—1 1.8 LT GRN - 24B(GPT )-P)OOj :8 LT GRN-24A(HOT) 8 LT GRN-24A GLOW PLUG GENTEBM1 TIMING LATCHING AND LEVEL DETECTION CIRCUITS DRIVE HI -12010719 DIESEL ENGINE GLOW PLUGS CONTROL MODULE 12004267- tp tp LAMP CHECK RELAY rh -12004105 CONN ASM SPLICE-150 TEST CONN H 2 0 I0 9 9 7 (ORANGE) 12004826. ASM ■12010649 .6 LT G RN-384— C-TRUCK ■t STOP LP CONTACTS 8 PNK/BLK-39B BRAKE SWITCH 12004215 * SOCKET NOTE- 3 i8 PNK/&LK-39C .8 LT BLU/BLK-383 8905581 SOCKET TO LAMP CHECK RELAY GLOW PLUGS '12004185 CONN ASM D Q 4 WD IN LT SWITCH INST LPS 5 AMP 12010808- g X )4 8 2 6 - K-TRUCK ® NOT USED TO MOOULE .8 LT BLU - 5 0 6 — .8 B R N -2 5 --------- ^260488Sn^=': FUSE BLOCK .8 G R Y -5 02 -------.8 BLK/WHT-5 0 0 .8 Y E L /B L K -5 0 5 - -12010649 TO BRAKE SWITCH TO WATER IN FUEL LAMP .8 Y E L -5 0 B A ----------- 12010973- 12004215 SOCKET .8 LT B LU /BLK-383A .6 PNK/BLK- 39E-----.8 LT B LU /BLK-363B.8 P N K /B L K -39 F ------.8 W H T -1 5 6 A -------------- 4 W DRIVE IND LIGHT 120*0015 4WD RELAY .8 W H T -I5 6 B -----------I 0 R N -5 0 3 A 8905381 SOCKET WATER IN « FUEL ■NORMAL .8 YEL- 506 (HW) .8 PNK-30(HW) - 4 WD SHIFT LEVER LIGHT " -----9905426 8 BLK-I50A .0 BLK-I50BHW)FRAME GROUND PRODUCTION TANK SENOER Fig. 8C-104--CK Truck Wiring LIGHT TRUCK SERVICE MANUAL TO GLOW PLUGS LAMP DIESEL ENGINE (RPO LF9) FOR RPO INSTRUMENT PANEL AND GAGES 8 C -117 Fig. 8C-105--CK Truck Wiring LIGHT TRUCK SERVICE MANUAL . ■■Aj ' ACCESSORIES 9-1 SECTION 9 ACCESSORIES CONTENTS Cruise Master.......................................................................................................9-1 General Description................................................................................ .........9-1 Diagnosis.............................................................................................................9-4 On-Vehicle Service................................................... ...................................... .9-8 Specifications......................................................................................................9-8 R a d io ................................................. .................................................................. .9-8 General Description........................................................................................ .9-8 Diagnosis................................... ........................................... ............................ .9-9 On-Vehicle Service.......................................................................................... .9-21 CRUISE MASTER GENERAL DESCRIPTION The Cruise Master is a speed control system which employs engine manifold vacuum to control the throttle power unit. The power unit moves the throttle, when speed adjustment is necessary, by receiving a varying amount of controlled vacuum from the transducer. The speedometer cable (from the transmission) drives the transducer, and a cable (from the transducer) drives the instrument panel speedometer. The engagement of the transducer unit is controlled by an engagement switch located at the end of the turn signal or multi-function lever. Two brake release switches are provided: an electric switch disengages the transducer and a vacuum valve decreases the vacuum in the power unit to quickly return the throttle to idle position. The purpose of the Cruise Master system is to allow the driver to maintain a constant highway speed without the necessity of continually applying foot pressure to the accelerator pedal. Speed changes are easily made and override features allow the vehicle to be stopped, slowed or accelerated as described below. SWITCH FUNCTIONS The switch functions of the cruise control lever (Fig. 9-1C) are as follows: ON - The cruise switch must be in the ON position and the vehicle speed above 30 mph (50 km/h) before the system can be engaged. SET-COAST - This is a dual function switch that operates in the following manner. • SET - Depress the "SET" button completely when vehicle reaches desired speed, and release the button slowly to engage system. Use of the brakes will disengage the system but pre-set speed will be retained in memory. • COAST - Cruise speed may be reduced by depressing "COAST" button until desired speed is reached, then releasing slowly to re-engage. Higher speeds are set by accelerating vehicle to desired speed and depressing "SET-COAST" button. RESUM E - Slide cruise switch to "RESUME" and release, vehicle will accelerate to previously set cruise speed. It is advisable not to use "RESUME" in city traffic or in suitations where the previously set speed is faster than the immediate traffic flow. Do not use "RESUME" or cruise control features on slippery conditions. D ISEN G A G EM EN T - The system is disengaged by applying the brakes. Under normal operation, it is not necessary to use the "OFF" position. Sliding the cruise switch to "OFF" or turning off the ignition will erase the memory and disengage the system. System can be momen­ tarily disengaged by holding in the "SET-COAST" button. DRIVER OPERATION Engaging the Cruise System Fig. 9-lC -R esum e Cruise Control Lever The driver accelerates to the desired cruise speed above 30 mph (50 km/h) and moves the "on/off" resume slider to the "on" position located on directional signal handle. The operator then fully depresses and slowly releases the cruise "set coast" button. A speed switch built into the transducer assembly prevents engaging the system below approx­ imately 30 mph (50 km/h). The cruise system takes over LIGHT TRUCK SERVICE MANUAL 9-2 ACCESSORIES ■'PPER FLEX SHAFT CONNECTION TO SPEEDOMETER ■PORT "C" ENGAGE HOLD PORT "B" .RESUME VALVE PORT TO MANIFOLD VACUUM P O R T"A ' RESUMESOLENOID RESUME' CONNECTOR Fig. 9-2C--Resume Cruise Control Transducer speed control, and within engine limitation, maintains this speed regardless of changes in terrain. Disengaging the Cruise System Disengagement occurs when the brake pedal is de­ pressed. This maintains previous set speed in the systems memory. Disengagement can also be accomplished by moving the " o f f " - " o n " - " r e s u m e " slider to the "off" position. This slider should be left in the "off" position when system usage is not intended. This removes any previous set speed from the memory. Resume Re-engagement of the Cruise System To re-engage the system after disengagement with the brake pedal, move the " o ff " - " o n " -" re s u m e " slider to the Resume position. The vehicle will return to that cruise speed existing at the time the brake pedal was depressed. Re-engagement at New Set Speed The system may also be reset to any speed desired above 30 mph (50 k m /h) by depressing the Set-Coast button all the way down and then releasing it slowly. To Cruise at a Higher Speed Depress the accelerator pedal to reach the new desired speed. Then depress and release the cruise control Set-Coast button. The system re-engages at the higher speed when the button is released. To Cruise at a Lower Speed Disengage the system by depressing the Set-Coast button fully and holding it there until the vehicle has decelerated to the new desired speed; then release the button LIGHT TRUCK SERVICE MANUAL slowly. The system re-engages at the lower speed when the button is slowly released. Lower speed can also be obtained by depressing the brake pedal which disengages the system. When the vehicle has slowed down to the desired lower speed, it may be re­ engaged by depressing the Set-Coast button and releasing it slowly. Cruise Master Components The cruise control switch is used to control the cruise system in the set, coast, or resume and off modes of operation. The Transducer (Fig.. 9-2C and 9-3C) is mounted in the speedometer cable line. It is a combination speed sensing device and control unit. When engaged, it senses vehicle speed and positions the servo unit to maintain the selected speed. It also incorporates internal design features which perform the "resum e" function in conjunction with the external resume vacuum control valve. • T H E SE R V O Unit is bracket mounted to the engine. It opens or closes the throttle as dictated by the Transducer. • The Cruise Brake Release Switch, which is mounted on the brake pedal bracket, disengages the system electri­ cally when the brake pedal is depressed. • The Cruise Brake Release Valve, which is mounted on the brake pedal bracket, disengages the system pneu­ matically when the brake pedal is depressed. • The Cable and Casing Assemblies drive the transducer and speedometer. ACCESSORIES 9-3 M ou n tin g LIGHT TRUCK SERVICE MANUAL 9-4 ACCESSORIES DIAGNOSIS ELECTRICAL SYSTEM TROUBLESHOOTING 1. Check fuse and connector. 2. Check brake electric switch as follows: a. Unplug connector at switch. b. Connect ohmmeter across cruise master contacts on brake switch. The ohm m eter must indicate no continuity when the pedal is depressed and continu­ ity when pedal is released. The cruise release brake switch (electric) is adjusted as is the standard stop light brake switch. c. Replace brake electric switch if needed. Electrical Test Refer to wiring diagram in Figure 9-5C to perform any electrical test. Engagement Switch Test Refer to Figures 9-6C and 9-7C to perform engage­ ment switch test. LIGHT TRUCK SERVICE MANUAL Resume Cruise Control Quick Checks Refer to Figure 9-7C for cruise control quick checks. Servo and Vacuum System Test To determine the condition of the Servo diaphragm, remove hose from the Power Unit and apply 15 inches of vacuum to the tube opening and hold in for one minute. The vacuum shall not leak down more than 5 inches of vacuum in one minute. If leakage is detected, replace the Power Unit. The cruise release brake valve (vacuum), resume valve and connecting hoses can be checked by applying 15" of vacuum to each component, then sealing them off. The vacuum leakage from 15" Hg should not excess 5 inches, in a one second interval. The cruise vacuum switch can be tested in the same manner. Leakage from 15" Hg should not exceed one inch in one minute. Harness Test 1. Disconnect engage switch wire harness connector from the main harness connector (red, brown/white, and white wires). ACCESSORIES PUSH BUTTC SLIDER OPERATION SLIDER IN "ON" POSITION PUSH BUTTON IN REST SLIDER IN "ON" POSITION PUSH BUTTON IN REST POSITION ~HOLD l ENGAGE i i l p o s it io n ! m iK iuttoh ~ | 1 tH O LD 9-5 OPERATION r-HOLD- 1r ENGAGE | m o ti | HOLD I— B+------!3 BRN 1} y2 BLKBLU HOLD SLIDER IN "OFF" SLIDER IN j SMUTTLI "ON" POSITION PUSH ---PUSHIUTTMI | BUTTON IN "COAST" Z HOLD POSITION B+ — (DEPRESSING MOTION) ENGAGE r~ SHUTTLE U r u PUSH BUTTON i n I tuTTI>11 REST POSITION t HOLD -B+- v v HOLD-----— ENGAGE I SHUTTLE SLIDER IN "ON" POSITION ----^ PUSHHITTOW I PUSH BUTTON t C lO L D IN "COAST" l B + ----------POSITION MIL HOLD ENGAGE SLIDER IN "RESUME" POSITION PUSH BUTTON IN REST POSITION v -H O L D ENGAGE (FULLY DEPRESSED)r SLIDER IN "ON" POSITION [s jilli1 PUSH BUTTON I—P IN "ENGAGE"-*H pmhmttw POSITION I HOLD (RELEASING Lb + MOTION) --------- SHOE! T hold B+ -H O L D — ENGAGE Fig. 9-5C--Cruise Control Switch O p eration S W ITC H FU N C TIO N TABLE S w itch C ondition T«t Order xx Slider |x Term inal Connections 362 1 &3 2& 1 Function End Button O ff Released O ff 0 0 R «um « Released Resume C C C Cruise Released On C 0 0 1 C o ilt H alf Depressed On 0 0 0 2 Coast Fully Depressed On 0 0 C 3 Set Releasing On c C c O = Open 0 C = Continuity x These test are continuity tests b etw een the term inals show n in figures of resum s cruise control lever and lever electrical operation, xx The slider m ust have a detent in the "o n " and " o ff" positions and must return to the "o n " detent w hen released from the resum e position. Fig. 9-6C--Cruise Control Switch Function Table LIGHT TRUCK SERVICE MANUAL 9 -6 ACCESSORIES RESUM E CRUISE CO NTROL Q U IC K CHECKS VEHICLE SURGES VEHICLE C RUISES OVER SET SPEED PERFO RM G ENERAL P R E L IM IN A R Y D IA G N O S T IC SYSTEM CHECK CHECK FOR BENT SPEEDO CABLE T IP CHECK FOR TO O LONG SPEEDO CABLE A S S EM B LY CHECK FOR BENT. K IN K E D . OR M IS R O U T E D CABLE & C A S IN G A S S EM B LY CHECK FOR B IN D IN G THROTTLE LINKAGE OR CRUISE CO NTR O L BEAD C H A IN OR B O W DEN CABLE. CHECK VEHICLE FOR CORRECT T R A N S D U C E R P /N OK • • • PERFORM G ENERAL P R E L IM IN A R Y D IA G N O S T IC SYSTEM CHECK IF OK, A D J U S T ORIFICE TUBE IN W A R D 1 /4 OF A T U R N A T A T IM E . RECHECK A T 55 M P H . NOTE: 1 /4 OF A T U R N EQUALS A P P R O X IM A T E L Y 1 MPH. NO T OK REPLACE TRANSDUCER REPLACE W IT H PROPER P /N T R A N S D U C E R RO A D TEST EXCESSIVE SPEED D O W N H IL L • • • • • PERFO RM G ENERAL P R E L IM IN A R Y D IA G N O S T IC SYSTEM CHECK CHECK FOR PLUGGED T R A N S D U C E R FILTER CHECK FOR W EAK THRO TTLE RETURN SP R IN G CHECK FOR B IN D IN G THRO TTLE LIN KAG E OR CR UISE C O N TRO L BEAD C H A IN ON B O W DEN CABLE REPAIR A S R EQ U IR E D A N D R O AD TEST VEHICLE CRUISES UNDER SET SPEED • • • • • PERFO RM GENERAL P R E L IM IN A R Y D IA G N O S T IC SY STEM CHECK CHECK FOR V A C U U M LEAKS A T ALL HO SES, POWER U N IT , BRAKE RELEASE VALVE CHECK FOR TOO M U C H PLAY IN TH R O TTLE LINKAGE OR CRUISE CO NTRO L BEAD C H A IN OR BO W DEN CABLE IF OK A D J U S T ORIFICE TUBE O U T W A R D 1 /4 OF A T U R N A T A T IM E RECHECK A T 55 M P H NOTE: 1 /4 OF A T U R N EQ UALS A P P R O X IM A T E L Y 1 M PH. GENERAL P R E L IM IN A R Y D IA G N O S T IC SY STEM CHECK 1. CHECK SERVO CABLE OR ROD A D J U S T M E N T FOR M IN IM U M SLACK. 2. CHECK V A C U U M HOSES FOR CRA C K S. K IN K S , S H A R P BENDS, OR M IS S IN G HOSES. 3. CHECK SPEEDO M ETER A N D D R IVE CABLES R O U TIN G FOR K IN K S OR S H A R P BEN DS A N D LOOSE C O N N E C TIO N . 4. CHECK A D J U S T M E N T OF V A C U U M VA LVE A N D ELECTRICAL S W IT C H VA LVE A N D ELECTRICAL SW IT C H A T BRAKE RELEASE S W IT C H A N D C O N N E C TIO N S. 5. CHECK ENGAGE LEVER FOR ELECTRICAL C O N N E C TIO N S A N D S M O O T H CO NTRO L F U N C TIO N . 6. CHECK FOR D A M A G E D SY S TE M C O M P O N E N T S . 7. CHECK FOR W O R K IN G SPEEDO M ETER . Fig. 9-7C--Resume Cruise Control Quick Checks LIGHT TRUCK SERVICE MANUAL ACCESSORIES 9-7 CRUISE CONTROL D IA G N O S IS (ALL SERIES) PRFI I M IN A R Y CHECKS 1. Check S e r v o C h a in o r rod adjustm ent. M u s t have m in im u m slack. 5. C he ck adjustm ent of brake release sw itch and v a c u u m release valve. 2. Check v a cu u m hoses. M u s t be in good co n d itio n - no re stric tio n s 6. C h e ck engagem ent sw itch operation. o r leaks. 7. If steps 1 t h ro u g h 6 do not solve the problem, c o n tin u e with 3. C heck d rive cable ro u tin gs. No k in k s o r s h a r p bends. 4. C heck throttle linkage o r cable fo r binding._____________________ diag n osis. C R U IS E C O NTRO L IN O P E R A T IV E J-----1. Check gages fuse. If blown 2. If fu se and p r e lim in a r y ch e ck s ok. t u r n ig n itio n to r u n position check w ir in g fo r s h o rt circu it. and c r u is e con trol sw itch on. 3. D isc o n n e c t 2 w ire c o n n e cto r at tra n sd u c e r. 4. C onne ct 12 volt test ligh t to g ro u n d and to engage w ire in connector. P u s h e ngagem ent button in part way. 5. Repeat test on hold w ire in connector. TEST LIG H T OFF AT TEST L IG H T ON T EST L IG H T OFF AT ONE W IR E O NLY AT BOTH W IR E S BOTH W IR E S (M A Y BE D I M ON HOLD W IR E ) \ Test engagem ent switch. C h e ck for poor g ro u n d C h e ck fo r open c ir c u it in (See test procedure) at tra n sd u c e r. b rn w ire from engagem ent If ok. C heck for open c irc u it remove tra n sd u c e r sw itch c o n n e cto r to brake in w ire if test light fo r repair. switch. C h e ck brake sw itch (sh o u ld did not lig h t R epair o r replace part have voltage on both te rm in a ls that ch eck s bad. w hen ig n itio n key is in r u n , ENGAGED SV / ° 4 SOLENOID V ALVE ^ i MB ■■4 - J k SERVO po sition and on/off sw itch on). / W* ^ a C h e ck for open in w ire p lu g -in . TRANSDUCER If ok. ch e ck engagem ent °^° TO BRAKE •*RELEASE VALVE from brake release switch to on/off sw itch to fu se panel ENGINE y VACUUM SOURCE RESUME SOLENOID sVALVE v NOT ENGAGED WITH SET SPEED IN MEMORY ENGINE VACUUM jv S'"*' SOURCE sw itch operation and replace if nece ssary. RESUME SOLENOID VALVE TO BRAKE RELEASE VALVE ENGAGEMENT SWITCH E N G A G E M E N T S W IT C H T E S T P R O C E D U R E USE AS S E L F POW ERED T EST LIGH T. LIG H T W ILL BE ON FOR EA CH T EST IF SW ITCH IS GOOD. CO N N ECTO R TER M IN A LS AND COLOR 1 - BROWN, 2 - BLUE, 3 - B LACK. T E R M IN A L S SW IT C H P O S IT IO N S ENGAGE BUTTON R ESU M E SW IT C H 1 to 2 1 to 3 Released on closed open open Fully Depressed on open open closed Partially Released on closed closed closed Released resume closed closed closed Released off open open open 2 to 3 REFER TO S E C T IO N 8 FOR W IR I N G FOR A L L S E R IE S Fig. 9-8C~Resume Cruise Control Diagnosis Chart LIGHT TRUCK SERVICE MANUAL 9-8 ACCESSORIES 2. Connect ohm m eter between point C (brow n/w hite stripe wire in main wire harness) and ground. Make sure the Transducer is well grounded to the chassis. The ohmmeter should read between 42 and 49 ohms. If a resistance either above or below the value indicated is shown, then disconnect the connector from the T rans­ ducer and measure the resistance of the brown/white stripe wire from point C to D. It should measure 40 ohms ± 2 ohms. 3. If a resistance either above or below the value indicated is shown, the main wiring harness should be replaced. NOTICE: When disconnecting or reconnecting the main wiring harness connector from the Transducer, care should be exercised so as not to damage the blade connectors or the wiring harness. The disconnect may be facilitated by prying carefully on the plastic connec­ tor with a small screwdriver. 4. Measuring the solenoid coil circuit resistance between point E (Hold Terminal) and ground, the ideal resist­ ance should be between 5 and 6 ohms. A reading of less than 4 ohms indicates shorting in the coil circuit. A reading of more than 7 ohms indicates excessive resistance in the coil circuit. Either extremity indicates replacement of the Transducer assembly. The main harness wiring from point F to G (white wire) should also be checked for continuity. ON CAR SERVICE Power Unit Bead Chain Adjustment 1. With air conditioning off, adjust engine curb hot idle speed, with the idle stop solenoid disconnected (if equipped), to 500 rpm, then shut off engine. 2. Check bead chain slack by unsnapping swivel from ball stud and holding chain taut at ball stud; center of swivel should extend 1/8 inch beyond center of ball stud. 3. Adjust bead chain slack if necessary, by removing the retainer from the swivel and chain assembly. Place chain into swivel cavities which permits chain to have slight slack. Place retainer over swivel and chain assembly. Brake Release Switch and Valve Adjustment With brake pedal fully depressed, push switch and valve forward until they stop against bracket or arm, pull pedal rearward with 15-20 lbs. force to properly adjust switch and valve. Cruise Speed Adjustment If the car cruises at a speed above or below the engagement speed, this error can be corrected with a simple adjustment of the orifice tube in the transducer. 1. To check cruise speed error, engage Cruise Control at exactly 50 mph. 2. If care cruise below engagement speed, screw orifice tube outward. 3. If car cruises above engagement speed, screw orifice tube inward. Each 1/4 turn of the orifice tube will change cruise speed approximately one mph. Snug-up lock nut after each adjustment before testing. Removal of Cruise Control Actuating Engagement Switch 1. Place shift lever in low and remove horn actuator and steering wheel. 2. Remove cover plate (three screws). 3. Remove turn signal lever and conduit from wire assembly. 4. Attach fine pliable wire through hole in connector. Tape end of wire and connector. 5. Pull switch and wire assembly through column. (Threading pliable wire). 6. Attach and tape wire to new connector. 7. Pull cofmector and wire through column. 8. Replace conduit on wire assembly. 9. Install turn signal lever screw. 10. Install cover plate. 11. Install steering wheel and horn actuator. TRANSDUCER Replacement 1. Disconnect battery ground cable. 2. Disconnect speedometer cables at transducer. 3. Disconnect vacuum and wiring harness at transducer body. 4. Remove transd ucer to bracket screws and remove transducer. 5. To install, reverse Steps 1-4 above. RADIO GENERAL DESCRIPTION Six types of radios are available: A M Pushbutton, A M / Stereo 8-Track Tape, A M /F M , A M /F M Stereo, A M /F M Stereo/Stereo tape, and A M /F M Stereo Cassette Tape. The left knob operates the on-off switch and volumne control, the left ring operates the tone control. The right hand knob controls manual tuning. All A M /F M radios have five push buttons (10 station selections) five on A M and five on FM. LIGHT TRUCK SERVICE MANUAL On models equipped with auxiliary speakers, a variable control located behind the manual tuning knob adjusts the volume of the front and rear speakers. Turn the control clockwise to increase rear speaker volume and decrease front speaker volume. Turn the control counterclockwise and the rear speaker volume decreases and the front speaker volume increases. Both speakers are controlled toegether by the volume control knob. ACCESSORIES 9-9 On models equipped with stereo radios, this control varies front and rear speaker volume to obtain the desired balance for stereo separation. DIAGNOSIS Diagnosis of radio portion of c a s s e tte - A M /F M is shown on the diagnosis charts. For cassette diagnosis, refer to Fig. 9-1R. If unit must be removed, it must be repaired by an authorized service station. See Section 8 for removal procedures and connections for speaker and power wiring. In diagnosing radio/tape problems the main point to remember is that you now have both a radio and a tape player to diagnose as part of the stereo system. By inserting test tape, J-22683-01, you can quickly determine whether the tape speed is proper. Since only the pre-amps and audio are common to both radio and tape, by listening for distortion with the tape playing and comparing it to the radio signal, you can further isolate the problem to either radio or tape; See the Diagnosis Chart. EIGHT-TRACK STEREO TAPE DIAGNOSIS STATIC AND NOISE DIAGNOSIS The tape player trouble diagnosis guide is intended as an aid in locating minor faults which can be corrected without a specialized knowledge of electronics and without special test equipment. If the suggestions given here do not effect a correction, further testing should be done only be a trained radio technician having proper test equipment. It should first be determined if the owner’s tape and not the player is at fault. Substituting a known good tape cartridge for the owner’s is a simple check. Refer to figure 9-3R for radio static suppression on the vehicle. Ground strap connections must be clean and tight, spark plug cables must be T V R S type and in good condition and resistance type spark plugs used. Extra electrical equipment added to the car could cause static if not properly grounded or wiring was improperly routed. Radio and antenna lead-in grounding must be clean and tight. An improperly trimmed antenna adjusting screw could result in poor sensitivity and static/noise on AM stations only. W eak FM station reception will be affected by near-by buildings, car speed, direction and windshield wiper opera­ tion. These "flutter," "swish" and "fading" conditions are characteristics of weak FM signals. CASSETTE TAPE PLAYER DIAGNOSIS Because tape player service problems are generally corrected by a radio repair shop, there is a tendency for many technicians to remove a set when a problem is reported. Removal of the tape player can frequently be avoided if the diagnosis chart is used to eliminate problems which can be easily fixed or which are not caused by a faulty player. CASSETTE TAPE PLAYER D IA G N O SIS TAPE ONLY TAPE W EAK TAPE DEAD IN S P E C T & CLEAN C H E C K P L A Y E R FOR O B S T R U C T IO N B E H IN D C A P S T A N AND H E A D ’ TRY A KNOW N GOOD DOOR TAPE C A R T R ID G E I________ NO O B S T R U C T IO N O B S T R U C T IO N TR Y A KNOW N REMOVE GOOD TAPE O B S T R U C T IO N C A R T R ID G E r DEAD NOT OK OK R EM OVE R A D IO A D V IS E C U ST O M E R FOR R E P A IR TAPE IS W ORN OR ♦ DEFECTIVE W ORKS REMOVE R A D IO U N IT A D V IS E C U S T O M E R FOR R E P A IR TAPE IS W O RN OR DEFECTIVE Fig. 9-1 R--Cassette Tape Player Diagnosis LIGHT TRUCK SERVICE MANUAL 9-10 ACCESSORIES DIAGNOSIS AM/FM-CB RADIO COMBINATION PROBLEM CHECK ACTION No AM, FM or CB sound No CB channel display. Check Fuse Remove radio for repair. No AM, FM or CB sound Channel display OK Mode Switch Squelch control Remove radio for repair No AM,or FM sound; CB sound OK Mode switch Squelch Remove radio for repair No CB sound and no channel display; AM/FM sound OK Mode switch R em ove radio for repair No CB sound, channel display OK; AM/FM OK. Mode switch Squelch Replace antenna Remove radio for repair Irregular channel stepping & unit not coordinated with display Cable connections Remove radio for repair Display segments missing or segment contrast not uniform Mode switch Remove radio for repair Channel display won’t change Selector switch Remove radio for repair Channel display indicates only “0 ” Power connector Remove radio for repair Fig. 9 - 2 R - A M / F M - C B R adio D iagnosis POPPING NOISE DIAGNOSIS Operating switches such as turn signal, pushing in cigarette lighter, operating stop lights, etc., may cause a popping noise on distant A M (weak) signals. Adjusting the antenna trimmer, if it is out of adjustment, will minimize the noise. TESTING WINDSHIELD ANTENNA (Fig. 9-4R) All C-K model trucks with factory installed radios are equipped with windshield antennas. To positively identify antenna failure and eliminate the possibility of unnecessary windshield replacem ent, Windshield A ntenna Tester J-23520 should be used to determine continuity of the thin antenna wire. W hen antenna failure is suspected, the following checks should be made before replacing the windshield. 1. Check Tester J-23520 for operation on any vehicle radio antenna that is operating normally to test for a weak or dead battery. 2. Check all antenna connectings to insure that antenna is electrically coupled to the radio. 3. Turn ignition switch to accessory position, turn radio "O N ", select A M band if receiver is A M /F M and tune radio to an off station position. 4. Hold tester to antenna beginning at the upper corner of antenna: NOTICE: The plastic shield must be on tester at all times to avoid scratching windshield. LIGHT TRUCK SERVICE MANUAL a. If a shrill sound is emitted through the speaker when both a ntenna wires are tested, a ntenna is operational. If no sound is emitted through one or both antenna wires, move tester along the wire toward center of windshield and down toward radio. If a shrill sound is picked up, find exact location where the noise begins, this is the area of the defect. Replace windshield. If no noise is heard over entire length of antenna, unplug antenna lead at radio and touch tester to antenna socket in radio. If radio now makes a shrill sound, check connectors and antenna lead for possible defect before replacing windshield. f. If no noise is emitted, radio, speaker, or fuse is defective. Make sure that antenna tester is turned off after completing antenna test. ACCESSORIES 9-11 BRAIDED GROUND BLOWER MOTOR CAPACITOR AM/FM FUSE PANEL [v i e w HOOD GROUND CAPACITOR BODY BRAIDED GROUND FRAME Fig. 9-3R--Radio Static Sup pre ssion -T ypical Fig. 9-4R--Testing Windshield Antenna (Typical) LIGHT TRUCK SERVICE MANUAL 9-12 ACCESSORIES RADIO NOISE DIAG NO SIS IMPROPERLY OPERATING IGNITION SYSTEM (HEI) CHECK FOR BROKEN CONTACT BUTTON ON ROTOR. f...... ■ CHECK FOR WORN CONTACT SPRING ON ROTOR OR SPRING BINDING IN HOLDER. .................................... fT— REPLACE. | ....... .................. CHECK FOR POOR INDEXING OF ROTOR SPRING. — ............................... | CORRECT OR REPLACE F —------------------ CHECK FOR BAD DISTRIBUTOR CAP (CARBON ERODED)._______________________________________ f REPLACE. = 3 -----| REPLACE. CHECK THAT CARBON CYLINDER IN DISTRIBUTOR CAP ---IS MOVING FREELY. _ REPLACE CHECK FOR GREASE ON ROTOR. CORRECT. CHECK FOR LOOSE GROUND SCREW ON IGNITION MODULE. CLEAN. CHECK FOR LOOSE GROUND SCREW ON DISTRIBUTOR CONDENSER. TIGHTEN. --------------------------------- 1 ' 1 TIGHTEN. Fig. 9-5R--Radio Diagnosis, Chart A LIGHT TRUCK SERVICE MANUAL WIRES. \ ACCESSORIES 9-13 RADIO NOISE — BLOWER MOTOR Fig. 9-6R--Radio Diagnosis, Chart B LIGHT TRUCK SERVICE MANUAL 9-14 ACCESSORIES DEAD RADIO — AM RADIO Fig. 9-7R--Radio Diagnosis, Chart C LIGHT TRUCK SERVICE MANUAL ACCESSORIES 9-15 DEAD RADIO — AM/FM RADIO AM ONLY DEAD AM AND FM DEAD FM ONLY DEAD REMOVE RADIO FOR EXCHANGE OR REPAIR. CHECK THAT ANTENNA IS PLUGGED INTO RADIO. MAKE SURE PLUG ISN ’T COCKED. CHECK FUSE. FUSE OK FUSE BLOWN BAD CONNECTION GOOD CONNECTION UNPLUG RADIO POWER LEAD. REPLACE FUSE. CHECK AT THE RADIO FOR FAULTY POWER CONNECTION OR SPEAKER CONNECTIONS. CHECK ANTENNA AND LEAD-IN WITH SUBSTITUTE ANTENNA. TRIM. (SEE P R O C E D U R E ) REPAIR CONNECTION. RADIO W O RKS STILL NO RECEPTION REPLACE MALFUNCTIONING ANTENNA OR LEAD-IN. RE-TRIM . REMOVE RADIO. FUSE D O E SN ’T BLOW FUSE BLOW S AGAIN CHECK ALL ACCESSORIES ON FUSE FOR PROBLEM. (SEE SERVICE MANUAL/TEST DRIVE IF NECESSARY.) CO RRECT PROBLEM. PLUG RADIO POWER LEAD BACK IN. FAULTY CONNECTION REPAIR CONNECTION. SUBSTITUTE SPEAKER. (USE FADER IF SO EQUIPPED.) NO RECEPTION REMOVE RADIO. RADIO W ORKS RADIO W O RKS STOP. FUSE BLOWS REMOVE RADIO. REPLACE M ALFUNCTIONING SPEAKER/W IRING ASSEMBLY. Fig. 9-8R--Radio Diagnosis, Chart D LIGHT TRUCK SERVICE MANUAL 9-16 ACCESSORIES DEAD RADIO — AM/FM STEREO C H E C K IF A L L S P E A K E R S A R E D E A D ( U S E F A D E R T O C H E C K .) NO YES S U B S T IT U T E B A D S P E A K E R ( S ) . SU BST IT U T E S P E A K E R W O RKS, BUT D EA D SP O T ON FADER* FM O N LY D EAD A M A N D FM D E A D |A M O N L Y D E A D SU BST IT U T E S P E A K E R D O E S NOT W O R K R E M O V E R A D IO R E M O V E R A D IO . R E P L A C E M A L F U N C T IO N IN G S P E A K E R / W IR IN G A S S E M B L Y A N D R E M O V E R A D IO . *FADER D EA D SPOT: A S FADER IS ROTATED, A P O SIT IO N IS FO UND AT WHICH O N E O R TWO S P E A K E R S S U D D E N L Y GO DEAD. S U B ST IT U T E S P E A K E R W O R K S A N D NO D E A D SP O T ON FA D ER* R E P L A C E M A L F U N C T IO N IN G S P E A K E R / W IR IN G A S S E M B L Y . CHECK FU SE] FUSE OK C H E C K T H A T A N T E N N A IS P L U G G E D IN T O R A D IO . M A K E S U R E P L U G I S N ’T C O C K E D FU SE BLOW N C H E C K A T T H E R A D IO F O R F A U L T Y P O W E R C O N N E C T IO N O R S P E A K E R C O N N E C T IO N S . U N P L U G R A D IO P O W E R L E A D , R E P L A C E F U SE. B A D C O N N E C T IO N GO O D C O N N E C T IO N R E P A IR C O N N E C T IO N C H E C K A N T E N N A A N D L E A D IN W IT H S U B S T IT U T E A N T E N N A . T R IM ( S E E P R O C E D U R E ) S T IL L NO R E C E P T IO N R E M O V E R A D IO l FU SE B L O W S A G A IN R A D IO W O R K S R E P L A C E M A L F U N C T IO N IN G A N T E N N A O R L E A D IN. FU SE D O E S N ’T BLO W C H E C K A L L A C C E S S O R IE S O N F U S E F O R P R O B L E M (S E E S E R V I C E M A N U A L / T E S T D R IV E IF NECESSARY) r P L U G R A D IO PO W ER LEAD B A C K IN. CORRECT PROBLEM FAULTY C O N N E C T IO N R A D IO W O R K S I R E P A IR C O N N E C T IO N S U B S T IT U T E S P E A K E R ( U S E F A D E R IF S O E Q U IP P E D . ) NO R E C E P T IO N REM O VE R A D IO R A D IO W O R K S R E P L A C E M A L F U N C T IO N IN G S P E A K E R / W IR IN G A S S E M B L Y . Fig. 9-9R--Radio Diagnosis, Chart E LIGHT TRUCK SERVICE MANUAL 1S T O P | E FU SE B L O W S R E M O V E R A D IO " ! SLIMLINE POWER ANTENNA DIAGNOSIS A N T E N N A W IL L N O T A N T E N N A W IL L NO T L O W ER T R A V E L TO F U L L U P O R DO W N (M O T O R D O E S N O T R U N ) P O S I T I O N S O R D O E S N 'T M O V E C H EC K FUSE C IG - C L K - D M (M O T O R R U N S ) (BE S U R E M A S T I S C L E A N ) __________I_________ \ FU SE BLOW N FU SE OK P u ll up o n top s e c tio n of m a s t I I If se c t io n m oves fre e ly, p la stic d riv e cable is b roke n. Fig. 9-1 OR—Slimline P ro b e o r a n g e w ir e t e rm in a l D is c o n n e c t c o n n e c t o r w ith at a n t e n n a re la y w ith 12V. o r a n g e w ir e at relay. test l i g h t ne w f u s e a n d re ch e c k. r In s t a ll “1 FUSE O K FU SE BLOW N BROKEN NOT B R O K E N D R IV E C A B L E L IG H T O N N O L IG H T t 1 R e p a ir s h o r t in o r a n g e w ire . D is c o n n e c t o t h e r co n n e cto r. C o n n e ct o r n w ire c o n n e c t o r, Power Antenna R em ove m ast a n d Replace m ast a nd U se a 12 v o lt test Locate a n d re p a ir s u p p o r t tube. C h e c k su p p o rt tube. lig h t a n d probe ope n c i r c u i t in m ast s e c t io n s fo r w h ite w ire at a n t e n n a o r a n g e w ire fro m f re e m o v e m e n t re la y c o n n e c to r. re la y to f u s e panel. re c h e c k f u se . FU SE BLO W N Diagnosis, Chart F L IG H T OFF L IG H T ON R eplace relay. B IN D IN G FREE FUSE OK C h e c k a n d r e p a ir w h ite w ir e to a n te n n a . R eplace f o r b ro k e n hook. OK If replace ge a r a sse m b ly . C h e c k w h ite w ire fro m re lay to a n t e n n a R elay C h e c k d riv e cable If O K r e p a ir a n t e n n a m otor i Free up s e c tio n s f o r open c ir c u it. o r replace m ast pro be dk. g r e e n w ire. If O K ANTENNA R E LA Y a n d su p p o rt tube. a n d spool a sse m b ly. L IG H T ON C h e c k dk. g r e e n w ire g r o u n d w ir e (black) a n d re la y to c o n n e c t o r a nd g r o u n d scre w . c o n n e c t o r to a n t e n n a replace relay. If OK. fo r loose c o n n e c t io n o r open c ir c u it. A C C E S S O R IE S C h e c k re la y c o n n e c t io n s ; NO L IG H T If O K re p a ir 9 -1 7 m otor asse m b ly. 9-18 SLIMLINE POWER ANTENNA DIAGNOSIS (CONT’D) ACCESSORIES A N T tN N A W IL L NOT GO U P IG N IT IO N A N D R A D IO S W IT C H E S ON (M O T O R D O E S NO T RUN) C h e c k F u se s (Radio a nd C ig - C lk - D m ) Fig. 9-11R—Slimline ----------} F U S E S BLOW N FU SES OK I T u r n ig n itio n off. C L K -C IG R A D IO FU SE F U SE Power Antenna D isc o n n e c t 3 w ire Remove c o n n e cto r w ith co n n e cto r w ith pin k LIG H T ON w ire at a n te n n a relay. In st a ll new fu se Locate and re p air open c ir c u it in o ra n g e w ire listen fo r relay click. from fu se panel to relay. Diagnosis, Chart G FU SE OK F U SE B L O W S (R E L A Y E N E R G IZ E D ) B LO W S f Locate and repair sh o rt co n n e cto r w ith w hite c ir c u it in orange w ire w ire and in sta ll co n n e cto r from fu se panel to con nector. C h e ck f o r : C h e ck yellow w ire from Replace fu se panel to radio and a n te n n a pin k w ire from radio relay. Probe Dk. Green w ire in relay con nector. to relay c o n n e cto r for sh o rt c ir c u iL relay. Recheck fuse. NO C L IC K C L IC K S FUSE FU SE O K I radio sw itch e s and T u rn o n ig n itio n and ff w ith o ra n ge w ire at a n te n n a L IG H T OFF ♦ In st a ll new radio fuse. and recheck. D isc o n n e c t 3 w ire jjeii w ire at the relay connector. ora n g e w ire fro m a n te n n a relay. Use a 12 volt test light and probe the o ra n g e 1. Open relay gro u n d . 2. Open pin k w ire from radio. 3. Bad radio switch. C heck with test light at pin k wire term inal. If OK If OK replace relay. rem ove radio fo r repair. kL0P6 U iu3e M1L6 i L IG H T ON L IG H T OFF \ Probe gra y w ire in F U SE BLOW N Replace sam e connector. F U SE OK relay. t Replace C h e ck g ra y and dk. green relay. w ire s from relay to an te n n a LIG H T OFF L IG H T ON motor co n n e cto r and to the I a n te n n a assem bly for sh o rt C h e c k co n n e cto r te rm in a ls C h e ck for open in w ire s or co n n e ctio n s: c irc u il for good contact to relay. gray to a n te n n a motor and dk. g r n from a n te n n a motor to relay. If O K remove If O K remove an te n n a motor fo r repair. OK. replace relay. \ If a n te n n a motor for repair. ACCESSORIES 9-19 POWER A N T E N N A General D escription and O peration T he po w e r a n te n n a a u to m a tic a lly raises the a n te n n a mast to its full h eight w he n ev e r the radio and ignition are t u rn e d o n . T he a n te n n a r e tra cts into the fender w h e n e ither the ignition or radio is tu rn e d o ff. T he p o w e r a n te n n a drive unit is h o u se d in a 2 piece plastic housing a tta c h e d to th e mast a nd tu b e a ssem bly. A p e r m a n e n t m agnet m o t o r w ith w o r m drive m oves the a n te n n a m ast up and d o w n w ith a plastic cable a tta c h e d to the to p m ast section. No clutch is used in this u n it. U pper a nd lower travel limits are c o n tr o lle d b y sw itches o p e n e d b y a r m a tu r e shaft th rust as the m ast reaches the end o f its travel. A circuit bre ake r is used to p r o t e c t th e m o t o r a r m a tu re from over heating . T w o ty p e s o f p o w e r a n t e n n a s are used d e p e n d in g on the t y p e o f radio used in the car: 1) AM -FM T yp e 2) AM-FM-CB (T ri-B a n d) T y pe T he AM-FM a n te n n a e x te n d s to a m a x i m u m height o f 7 9 4 m m (31 1 / 4 ” ). T h e AM-FM-CB (T ri-B and) a n te n n a e x te n d s to a height o f 9 1 4 m m ( 3 6 ” ). T h e tri-band a n te n n a has a load coil m o u n te d o n th e c en ter mast section to tu n e it to th e CB radio b a n d and a stub a n te n n a lead tape d to the su p p o rt t u b e . The stub m a tc h e s the a n te n n a to the FM b a n d a nd should no t be rem oved e x c e p t for re p la c e m e n t. On Car Service T h ere is no on car service o f th e AM-FM a n te n n a o t h e r t h an cleaning o f th e m ast sections. O n the T ri-B and a n te n n a the load coil and tip are servicable in th e event o f da m a ge o r loss. T he load coil h a s an a d ju s ta b le b a n d t o set SWR ( S ta n d in g Wave R a ti o ) for CB o p e r a t io n . T h e SWR is preset o n c o m p le te a n te n n a assemblies b u t re p la c e m e n t load coils m ust be ch ec k ed a n d /o r a d ju s te d using available SWR m ete rs . Checking SWR o e r v nr 'ore b* boori N O T IC E : S W R ch ec k in g procedures require t r a n s m itte r o p e r a t io n a nd FCC regu lations governing CB ra dio o p e r a t io n a p p ly . T he follow ing o p t io n s are available. • Have SWR test p e rfo r m e d b y a tec h n ic ia n w h o has a CB license. • Acquire a dealership CB radio o p e r a t o r ’s license w h ic h allows tec h n ician s to use license d u r in g business h o u rs . • Ask o w n e r or an o p e r a t o r possessing a p e r m a n e n t CB R a d io license to p r o p e rl y o p e ra te t r a n s m itte r du ring the test. A d j u s t m e n t s or repairs re fe rre d to in the p r o c e d u re th a t f ollo w s are limited to th e a n te n n a itself or the a n te n n a lead in an d c o n n e c ti o n s . MOTOR AND GEAR HOUSING CO VER CLIPS SWITCH AND H ARN ESS ASSEM BLY C IR C U IT B R EA K ER LIM IT SW ITCHES BRUSHES G EA R AND SPOOL A SSEM BLY BEAR IN G TH R U ST BLO CKS F IE L D M AGNET ASSEM BLY MAST AND / TUBE ASSEM BLY MOTOR AND GEAR HOUSING ARM ATURE ASSEM BLY CABLE STUB LEA D CONNECTION DRAIN TUBE Fig. 9-12R--Slimline Power Antenna Diagnosis, Chart H LIGHT TRUCK SERVICE MANUAL 9-20 ACCESSORIES SWR (S T A N D IN G W A V E R A T IO ) C H E C K 1. With Ignition and Radio off install an SWR meter as shown following meter manufacturers instructions. NO TICE: Operation of transmitter requires FC C CB Operators License. When making this check, car should be at least 20 feet away from any building, hood closed and no one should be standing close to the antenna. 2. Turn on Ignition and Radio, 3. Check Antenna height - Must be fully extended. 914 mm (36”) from fender to tip 286 mm (11-1 /A") top of load coil to tip. 4 After adjustment is complete apply a small amount of thread cement to adjusting band. LEAD IN CABLE FROM A N TE N N A LE A D IN CA BLE TO AM-FM RAD IO SWR M ETER RF JUMPER CA B LE CB R AD IO IN -LIN E S P LITTE R BOX T R A N SM ITT ER SO CK ET '\t A»l11,11" " I / / S L O A D C O IL A D J U S T M E N T S T U R N O N L Y 1 /8 th T U R N A T A T IM E SWR / CH A N N EL 40 H IGH ER PO SSIBLE SWR R E A D IN G S MOVE B A N D — ^ 1. Initial readings taken on Channel 1, 20, 40 a. SWR of 2:1 or lower on Channel 20 and nearly equal on Channels 1 and 40 is considered good. No adjustment required. b. SWR higher than 2 1 on Channel 20. Adjustment required. c. Unequal SWR on Channels 1 and 40 (one channel in red) indicates adjustment required L 40 f CLOCKW ISE* MOVES BAND DOWN CO U N TER C LO C K W ISE' M OVES BAND UP 'R O TA TIO N LO OKING DOWN A N Y R E A D IN G IN T H E R E D B A N D (A B O V E 3:1 SW R) C H E C K F O R : — Antenna mounting screws tight making a good ground connection — Lead in cable connections between antenna mounting surface and car sheet metal. to radio, splitter and antenna are tight, L e a d in c a b le s n o t p in c h e d a n d c u t t i n g t h e i n s u la t i o n . Fig. 9-13R—Slimline SW R Check LIGHT TRUCK SERVICE MANUAL ACCESSORIES 9-21 ON VEHICLE SERVICE MAINTENANCE AND ADJUSTMENTS TAPE PLAYER MAINTENANCE The only required m aintenance on tape players is periodic cleaning of the tape player head and capstan. This service should be performed every 100 hours of operation. Since you can reach them through the tape door, you can leave the tape player in the truck. To clean the head and capstan, use a cotton swab dipped in ordinary rubbing alcohol. Wipe the head and capstan as shown in Figure 9-15R . No lubricants should be used since they will cause the player to operate improperly, especially at extreme temperatures. Do not bring any magnetized tools near the tape head. If the head becomes magnetized, every cartridge played in the player will be degraded. To operate the tape player, completely insert a car­ tridge into the unit. This turns the tape player on, autom ati­ cally removes power from the radio, and switches the speakers from the radio to the tape player. This feature prevents accidental damage to the radio should the owner attempt to operate it while the tape player is in use. After the tape player is in operation, the front panel controls of the player are then adjusted for the most pleasant stereo listening. The tape player is equipped with a cartridge locking arm to hold the cartridge in a rigid position against the capstan drive for minimum wow and flutter. As the car­ tridge is withdrawn from the player, the on/off switch at the other side of the cartridge is not completely disengaged when the cartridge lock arm reaches a detent point on the cartridge. Always withdraw the cartridge just beyond the detent point for normal operation from the radio. Tape cartridges should be handled carefully and should be kept clean and out of direct sunlight. A cartridge should not be left inserted fully in the player. This may cause permanent damage to the cartridge. ANTENNA TRIMMER ADJUSTMENT-ALL RADIOS (Fig. 9-16R) The antenna trimmer adjustment must be made any time the radio is removed and installed, a new windshield or lead-in is installed or if weak, AM reception is noted. (Fig. 9-6R). COMPONENT PART REPLACEMENT RADIO OR RADIO TAPE REMOVAL (Refer to Section 8). RADIO DIAL LAMP REMOVAL (Refer to Section 8). RADIO SPEAKER REMOVAL (Refer to Section 8). ANTENNA C-K Models 1. T U R N R A D IO O N A N D TU N E R A D IO FOR W EAK S T A T IO N A T OR N E AR 1400 KC. 2. RE M O V E R IG H T H A N D KNOBS. 3. T U R N V O L U M E UP. 4. C A R E F U L L Y T U R N A N T E N N A T R IM M IN G SCREW BACK AND FORTH U N T IL M A X IM U M V O L U M E IS O B T A IN E D . SET T R IM M E R A T PEAK V O L U M E . N O TE: O N CARS W IT H POWER A N T E N N A , T R IM W IT H MAST F U L L Y E X T E N D E D 9 -1 6 R -T rim m in g R a d io Fig. 9-15R-Cleaning Tape Player Head LIGHT TRUCK SERVICE MANUAL 9-22 ACCESSORIES Antenna Replacement Refer to Section 2 of this manual "Windshield Re­ placement" procedure. Cable Replacement (Fig. 9 -1 7R) 1. 2. 3. 4. Disconnect battery ground cable. Unsnap antenna cable from windshield. Remove bracket to dash panel screws. Disconnect cable at rear of radio receiver and remove cable assembly. G Models Antenna Replacement (Fig. 9 -1 8R) 1. Unscrew mast nut. Prevent the cable assembly from turning by using two separate wrenches. Remove rod and mast assembly. 2. To install, insert rod and mast assembly into cable assembly and tighten mast nut. Prevent cable assembly from turning by using a second wrench. Cable Assembly Replacement (Fig. 9 -1 8R) 1. Disconnect battery ground cable. 2. Remove antenna assembly as described above. 3. Remove cable body nut and then remove seal, bezel, gasket and ring ground. 4. Perform Steps 2-8 of "R ad io Receiver Rem oval". Refer to Section 8. 5. Disconnect cable at rear of receiver. 6. Insert new cable through the dash panel (from the forward side). 7. Reverse Steps 1-5 above to complete installation. Be sure cable grommet is properly positioned in dash panel. POWER ANTENNA DESCRIPTION A N D OPERATION The power an ten na used on " G " models operates automatically whenever the radio is turned on. The drive gear unit on the automatic system consists of a drive gear and pulley assembly and a spool for storing the excess nylon Fig. 9-19 R--G M o d e l Power Antenna drive cable when the mast is in the retracted position, plus two limit switches and a gear operated cam system to actuate the switches. The limit switches are used to open the motor circuits when the mast reaches the full up or down positions. When the motor circuit is completed by the radio or ignition switch, the motor drives the gear and pulley to extend the drive cable and antenna. The gear is coupled to limiting clutch that permits the mast reaches the limit of retracts into the fender or intermediate position. the drive pulley by a torque continued gear rotation when travel. The antenna mast fully extends 3 1 - 1 / 4 " and has no POWER ANTENNA - G MODELS Replacement (Fig. 9-19R and 9-20R) 1. Lower antenna by turning off radio or ignition. 2. Disconnect battery ground cable. 3. Remove coolant recovery bottle. Fig. 9 -2 0 R -G M odel Power Antenna W iring LIGHT TRUCK SERVICE MANUAL ACCESSORIES 9 -23 PO W ER ANTENNA RELAY " Fig. 9 -21 R--G M o d e l Pow er Antenna Relay 4. Remove motor lower bracket retaining nut and upper bracket screws. 5. Disconnect electrical leads and remove antenna and motor assembly. 6. To install, reverse steps 1-5 above. POWER ANTENNA RELAY The power antenna relay is bracket mounted to the parking brake assembly as illustrated in figure 9*21 R. LIGHT TRUCK SERVICE MANUAL 9-24 ACCESSORIES POWER ANTENNA DISASSEMBLY-SLIMLINE NOTICE: W i t h the e x c e p t io n of load co il on the tr i- b an d ant e nn a , all service o pe r a ti o n s requ ir e ope ni ng the m o t o r and gear hou sing. A l l disassembly w i l l re quire a b o l t and clip package. 1. REMOVE A N D IN STA LL MOTOR AND GEAR HOUSING COVER. R EM O V A L INSTALL 1. Remove parts shown. 2. Seperate housing and cover as shown. 1. Re m o v e loose or excess sealer and reassemble using 3 bo lt s and n u ts , f r o m service package and the 5 clips. 2. A p p l y R T V sealer a r o u n d s u pp o rt t u b e a nd along seam o n t o p half of hou sing. EY ELETS MOTOR AN D GEAR H O U S IN G CO VER R o ll L ip o f Eye let up or Dr ill Ou t to Rem o ve Eye let. MOTOR AN D GEAR H O U S IN G SC RE W D R I V E R NOTCHES MAST A N D TUBE ASSEMBLY CLIPS 2. REM OVE A N D IN STA LL MAST A N D TUBE ASSEMBLY. REMOVAL IN S TA LL 1. Reassemble as shown with mast extended to reduce length of cable. 2. Run motor to lower mast into support tube. Reseal housing and support tube. 1. Remove parts as shown MOTOR AN D GEAR H O U S IN G C OVER GREEN CONNECT B A TT E R Y LEADS CABLE HOOK TO RAISE MOTOR AN D GEAR H O U S IN G Disengage cable from gear by rotating cable90 Fig. 9-22R--Slimline Disassembly I LIGHT TRUCK SERVICE MANUAL TO LOWER ACCESSORIES 9-25 3. REMOVE AND INSTALL SWITCH AND HARNESS ASSEMBLY. REMOVAL INSTALL 1. R em o v e parts as sh ow n . 1. Pos ition s w it ch . 2. Re m o ve excess sealer w he r e w ir e goes th r o u g h housing. 2. Reseal area w he r e wir es come o u t o f housing. Reseal housing. S W IT C H A N D H A R N E S S ASSEMBLY be tw e e n th r u s t b lo c ks 4. REMOVE AND IN STA LL A R M A TU R E A N D M AG NET ASSEMBLY. IN S TA LL REMOVAL 1. R em o v e parts as sh ow n . 2. Cle a n ou t o ld grease. 1. L u b ri c a te w o r m and gear w i t h l i t h i u m soap grease such as Sun Prestige # 2 o r equ iv a le n t. Oil 2. A p p l y d r o p o f light o il t o bearings. 3. Reassemble and seal housing. Fig. 9-23R~Slimline Disassembly II LIGHT TRUCK SERVICE MANUAL 9-26 ACCESSORIES REMOVE AND INSTALL GEAR ASSEMBLY. REMOVAL IN STA LL 1. Disassemble as shown. 2. Clean out old lubricant. 1 . Apply lubricant to worm and gear. 2. Reassemble and seal housing. SWITCH A N D HARNESS MOTOR A N D GEAR H OUSING C OVER / MAST AND TUBE ASSEMBLY GEAR A N D SPOOL ASSEMBLY MOTOR AN D GEAR H OUSING CABLE 1 X CABLE HOOK 6. REMOVE AND INSTALL CB LOAD COIL AND/OR TIP. REMOVAL IMSTALL 1. Disconnect Net). Battery Cable. 1 2. Turn on ignition and radio then connect battery long enough to raise antenna about half way. 2. Adiust S.W.R. (See SWR adjustment procedure) Reassemble as shown using thread cement to lock in place. 3. Remove parts as shown using padded pliers. TIP LOAD COIL (USED ON AM FM CB TR I BAND A N T E N N A O N LY ) \ Fig. 9-24R--Slimline Disassembly III LIGHT TRUCK SERVICE MANUAL METRIC AND FASTENER INFORMATION SECTION 10 METRIC & FASTENER INFORMATION USE OF METRIC AND CUSTOMARY NUTS, BOLTS AND SCREWS Some of the 1981 model cars present special service requirements to the technician due to the use of both metric and customary (inch) type nuts, bolts and screws on the same car. Many are metric and some are very close in dimension to customary nuts, bolts and screws in the inch system. Mismatched or incorrect nuts, bolts and screws can result in damage, malfunction or possible personal injury. Nuts, bolts and screws removed from the car should be saved for re-use whenever possible. If they are not re-usable, care should be taken to select a replacement that matches the original. ( /X;i General Motors Engineering Standards have adopted a portion of the standard metric fastener sizes defined by SI (Systeme International). This was done to reduce the number of sizes used and yet retain the best strength characteristics in each thread size. For example, the customary 1/4-20 and 1/4-28 screws are replaced by the metric M6.3 x 1 screw which has nearly the same diameter and 25.4 threads per inch. The thread pitch is in between the customary coarse and fine thread pitches. Metric and customary thread notation differ slightly. The difference is illustrated below. CUSTOMARY METRIC 1/4 M6.3 Thread Major Thread Major Diameter Diameter in Inches in Millimeters 20 1 Number of Distance Threads Between Threads per Inch in Millimeters Care should be taken when servicing the car to guard against cross threading or improper retention due to interchanged metric and inch nuts and bolts. When obtaining metric or customary nuts, bolts, and screws locally for servicing the car, care must be exercised in selecting parts that are equivalent to the original parts in dimensions, strength, and pitch of threads. 10-1 10-2 METRIC AND FASTENER INFO RM A TIO N REUSE OF P R E V A IL IN G T O R Q U E N U T(S) A N D BOLT(S) P R E V A IL IN G TO R Q U E N U TS A R E TH O SE N U TS W HICH IN C O R P O R A T E A S Y S TE M TO D E V E L O P AN IN T E R F E R E N C E B ETW EEN N U T A N D B O L T T H R E A D S IN T E R F E R E N C E IS MOST CO M M O N LY A C H IE V E D BY D IS T O R T IN G TOP O F A L L -M E T A L N U T, B U T A L S O M AY BE A C H IE V E D BY D IS T O R T IN G A T M ID D L E OF H E X F L A T , B Y N Y LO N P A TCH ON T H R E A D S , BY N Y LO N W A SH ER IN S E R T A T TOP OF N U T A N D B Y N Y LO N IN S E R T T H R O U G H NU T. P R E V A IL IN G T O R Q U E B O LT S A R E T H O S E B O LT S W H ICH IN C O R P O R A T E A S Y S T E M TO D E V E L O P AN IN T E R F E R E N C E B ETW EEN B O L T A N D N U T OR T A P P E D H O LE T H R E A D S . IN T E R F E R E N C E IS A C H IE V E D BY D IS T O R T IN G SOME OF T H E T H R E A D S (S E V E R A L M ETH O D S E X IS T ), BY A P P L Y IN G A N Y LO N PA T C H OR S T R IP OR BY A D H E S IV E C O A T IN G ON TH READ S. PRE VAILING TORQUE NUTS PRE VAIL ING TOR QU E BOLTS (I ° I ) TOP LO CK M AN Y TYPES I® CEN TER LO CK D R Y A D H E S IV E C O A T IN G GSD N Y LO N IN S E R T O U T OF R O U N D T H R E A D A R E A NYLON P A TCH Q N Y LO N W ASH ER IN S E R T N Y LO N S T R IP OR P A TCH T H R E A D P R O F IL E D E F O R M E D R E C O M M E N D A T I O N S FOR REUSE A. C LEAN . UNRUSTED FOLLO WS : 1. 2. 3. 4 5. B P R E V A ILIN G TORQUI BOLTS AND N IT S MAY Bl R EU SE D AS C L E A N D IR T A N D O T H l R FO R E I G N M A T E R I A L OL E NI T A N D BOLT INSPECT B O L T A N D N I T TO ASSURE T i l l Rl A R L NO ( RAC KS. E L O N G A T I O N OR O T H E R SIGNS Of ABUSE OR O V E R T I G H T E N I N G . L IG H T L V L U B R I C A T E T H R E A D S . ( I F A N Y D O U B T . RE PL A CE WI TH NEW P R E V A I L I N G TO RQ UE F A S T E N E R OF E Q U A L OR G R E A T E R S T R E N G T H .) ASSEMBLE PARTS A N D S T A R T B O L T OR N UT . OBSERVE T H A T BEFORE F A S T E N E R SEATS. IT DE VE L OP S P R E V A I L I N G TO RQ UE PER C H A R T Bl LOW ( IF A N Y D O U B T . I N S T A L L NEW P R E V A I L I N G T O R Q U I FA S T E N E R OF E Q U A L OR G R E A T E R S T R E N G T H ) . T I G H T E N TO TO RQ UE SPE C IF IE D IN S E R V K I M A N U A L . BO LTS A N D N I T S WHIC H ARE RU ST Y OR D A M A G E D SHOl L I ) BE R E P L A C E D W IT H NEW PARTS OF E Q U A L OR G R I A T E R ST R l N G TH . METRI r NUT S A N D A L L M E T A L BOLTS s izes 6 & 6.3 8 10 i: 14 16 20 0.4 0.8 14 2.2 3.0 4.2 7.0 4.0 7.0 12 18 25 35 57 0.4 0.6 12 1.6 2.4 3.4 5.6 5.0 10 14 20 28 46 N Mil In I bs. N • in A D H E S I V E OR N Y L O N C O A T E D BOLTS In. I hs. 4.0 INCH SIZES NUTS A N D A L L M E T A I BOLTS N • in In. Lbs. N •m A D H E S I V E OR N Y L O N C O A T E D BOLTS In. Lbs. .375 .437 .500 .562 .625 .750 0.6 . 1.4 1.8 2.4 3.2 4.2 6.2 4.0 5.0 12 15 20 27 35 51 0.4 0.6 1.0 1.4 1.8 2.6 3.4 5.2 4.0 5.0 9.0 12 15 11 28 43 .250 .312 0.4 METRIC AND FASTENER INFO RM A TIO N 10-3 METRIC BOLT AND NUT IDENTIFICATION Common metric fastener strength property classes are 9.8 and 10.9 with the class identification embossed on the head of each bolt. Customary (inch) strength classes range from grade 2 to 8 with line identification embossed on each bolt head. Markings correspond to two lines less than the actual grade (i.e. grade 7 bolt will exhibit 5 embossed lines on the bolt head). Some metric nuts will be marked with single digit strength identification numbers on the nut face. The following figure illustrates the different strength markings. GRADE 2 (GM 2 0 0 -M) GRADE 5 (GM 280-M ) GRADE 7 (GM 290-M ) GRADE 8 (GM 300-M ) C u sto m a ry (inch) bolts - Id e n tific a tio n m arks co rre sp o n d to bo lt strength - In cre asin g num bers represent increasing strength. M e tric B o lts - Id e n tific a tio n class n u m be rs c o rre sp o n d to bo lt strength - In cre asin g num be rs represent increasing strength. MANUFACTURERS ID E N T IF IC A T IO N NUT STRENGTH ID E N T IF IC A T IO N PO SID RIV SCREW HEAD ID E N T IF IC A T IO N MARKS (4) 10-4 SI METRIC-CUSTOMARY CONVERSION TABLE Multiply millimeters (mm) meters (m) meters kilometers (km) 25.4 0.304 8 0.914 4 1.609 AREA millimeters2 (mm2) centimeters2 (cm2) meters2 (m2) meters 645.2 6.45 0.092 9 0.836 1 Inch2 Foot2 Yard2 16 387. 16.387 0.016 0.946 3.785 0.764 Quart Gallon Yard meter/sec2 (m/s2) meter/sec2 TORQUE 0 112 98 1.355 8 Pound-inch Pound-foot newton-meters (N*m) newton-meters POWER 0.746 Horsepower kilowatts (kW) PRESSURE OR STRESS mm/ cm liters (1) liters liters meters3 (m3) 4 4 4 6 MASS Inches of mercury Pounds/sq. in. 3.377 6.895 kilopascals (kPa) kilopa seals ENERGY OR WORK BTU Foot-pound Kilowatt-hour kilograms (kg) kilograms (kg) tonne (t) 0.453 6 907.18 0.907 Pound Ton Ton 0.304 8 0.025 4 Foot/sec2 Inch/sec2 VOLUME Inch* to get equivalent number of: by ACCELERATION LENGTH Inch Foot Yard Mile METRIC AND FASTENER INFORMATION to get equivalent number o f: by Multiply 1 055. 1.355 8 3 600 000 or 3 .6x10* joules (J) joules joules (J = one W’s) LIGHT Foot candle 10.764 lumens/meter2 (lm/m2) FORCE FUEL PERFORMANCE 9.807 0.278 0 4.448 Kilogram Ounce Pound newtons (N) newtons newtons Miles/gal Gal/mile (°F-32) v 1.8 °F -40 0 -40 20 1 i i i i i 1 i i °C 32 1 40 t 0 degree Celsius (C) 20 120 i 40 37 Miles/hour r 609 3 kilometers/hr. (km/h) °F 98.6 80 1 1 ..i..i i l l kilometers/liter (km /1) liters/kilometer (1/km) VELOCITY TEMPERATURE Degree Fahrenheit 0.425 1 2.352 7 . i 212 200 , 160 ; i t i i i i i i i il 1 i t 60 80 100 °c I METRIC AND FASTENER INFO RM A TIO N 10-5 DECIMAL AND METRIC EQUIVALENTS Fractions 1/64 1/32 3/64 1/16 5/64 3/32 7/64 1/8 9/64 5/32 11/64 3/16 13/64 7/32 15/64 1/4 17/64 9/32 19/64 5/16 21/64 11/32 23/64 3/8 25/64 13/32 27/64 7/16 29/64 15/32 31/64 1/2 ___ . . . . . . . . . . ___ . ___ . ___ . . ___ . ___ . ___ . ------- . . ___ . ___ . ___ . ___ . . . ___ . ___ . . ___ . ___ . ___ . ___ Decimal In. .015625 . . . .03125 . . . .046875 . . . .0625 . . . . .078125 . . . .09375 . . . .109375 . . . .125 ......... .140625 . . . .15625 . . . .171875 . . . .1875 .203125 . . . .21875 . . . .234375 . . . .250 ......... .265625 . . . .28125 . . . .296875 . . . .3125 ___ .328125 . . . .34375 . . . .359375 . . . .375 ......... .390625 . . . .40625 . . . .421875 . . . .4375 . . . . .453125 . . . . .46875 . . . .484375 . . . .500 ......... . Metric MM. .39688 .79375 1.19062 1.58750 1.98437 2.38125 2.77812 3.1750 3.57187 3.96875 4.36562 4.76250 5.15937 5.55625 5.95312 6.35000 6.74687 7.14375 7.54062 7.93750 8.33437 8.73125 9.12812 9.52500 9.92187 10.31875 10.71562 11.11250 41.50937 11.90625 12.30312 12.70000 Fractions 33/64 17/32 35/64 9/16 37/64 19/32 39/64 5/8 41/64 21/32 43/64 11/16 45/64 23/32 47/64 3/4 49/64 25/32 51/64 13/16 53/64 27/32 55/64 7/8 57/64 29/32 59/64 15/16 61/64 31/32 63/64 1 ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... Decimal In. .515625 . . .53125 . . . .546875 . . .5625 . . . .578125 . . .59375 . . . .609375 . . .625 . . . . .640625 . . .65625 . . . .671875 . . .6875 . . . .703125 . . .71875 . . . .734375 . . .750 ___ .765625 . . .78125 . . . .796875 . . .8125 . . . .828125 . . .84375 . . . .859375 . . .875 . . . . .890625 . . .90625 . . . .921875 . . .9375 . . . .953125 . . .96875 . . . .984375 . . 1.00 ......... Metric MM. 13.09687 13.49375 13.89062 14.28750 14.68437 15.08125 15.47812 15.87500 16.27187 16.66875 17.06562 17.46250 17.85937 18.25625 18.65312 19.05000 19.44687 19.84375 20.24062 20.63750 21.03437 21.43125 21.82812 22.22500 22.62187 23.01875 23.41562 23.81250 24.20937 24.60625 25.00312 25.40000