Page 1 1975 CHEVROLET LIGHT DUTY SERVICE TRUCK www.PlandeGraissage.Org...
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Page 3 Consequently, Chevrolet 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 vehicle safety will be jeopardized by the service method he selects.
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Page 5 STEERING procedures for maintenance and adjustments, minor service op erations and replacement of components. WHEELS AND TIRES CHASSIS SHEET METAL ELECTRICAL—BODY CHEVROLET MOTOR DIVISION AND CHASSIS RADIATOR AND GRILLE General M otors Corporation DETROIT, MICHIGAN ACCESSORIES SPECIFICATIONS — AT REAR OF MANUAL www.PlandeGraissage.Org...
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Page 7: Table Of Contents
2 letters followed by five numbers. The first letter indicates a Chevrolet model and the second identifies the Warranty Reports, Product Information Reports, or chassis type. The first number designates the GVW...
Page 8: Truck Model Identification
0-2 GENERAL INFORMATION AND LUBRICATION TRUCK MODEL IDENTIFICATION C C 10703 1. CHEVRO LET 2. CHASSIS TYPE 3. GVW RANGE - 4. CA D IM E N S IO N /M O D E L TYPE 5. CAB OR BODY S T Y L E ------------ ©...
Page 9: Service Parts Identification Plate
DIVISION L = V 8-454-4 information. —MODEL YEAR C = CHEVROLET ALW AYS REFER TO T H IS IN F O R M A T IO N 5 = 1975 fo r al T = GMT W H E N ORDERING PARTS.
Page 10 0-4 GENERAL INFORMATION AND LUBRICATION would cause personal injury. Batteries and • A vehicle with a discharged battery may be started battery acid should always be kept out o f reach by transferring electrical power from a battery in o f children. another car - called "jump starting".
Page 11 GENERAL INFORMATION AND LUBRICATION STEEL TU B IN G REPLACEM ENT TO W IN G In the event that replacement of steel tubing is required All Except Four Wheel Drive Trucks on brake line, fuel line, evaporative emission, and Normally your vehicle may be towed with all four wheels transmission cooling lines, only the recommended steel on the ground for distances up to 50 miles at speeds of replacement tubing should be used.
Page 12: Maintenance Schedule
0-6 GENERAL INFORMATION AND LUBRICATION Universal Joints..............0-9 Four Wheel Drive Propeller Shaft Centering Ball........0-10 Wheel Bearings Front Axle................. 0-10 Front..................0-9 Air Vent Hose..............0-11 R ear..................0-9 Transfer Case..............0-11 Brake Master Cylinder............0-9 Control Lever and Linkage........0-11 Brake and Clutch Pedal Springs........
Page 13: Drive Belts
GENERAL INFORMATION AND LUBRICATION period. However, check the oil level more frequently The oil level should be maintained in the safety margin, during the break-in period since higher oil consumption neither going above the "FULL" line nor below "ADD is normal until the piston rings become seated. OIL"...
Page 14: Air Cleaner
0-8 GENERAL INFORMATION AND LUBRICATION and stops, to bring transmission up to normal AIR CLEANER operating temperature (approximately 180-190®F). 2. Park vehicle on a level surface. Do not remove the engine air C A U TIO N : 3. Place selector lever in "Park" and leave engine cleaner unless temporary removal is necessary during repair or maintenance o f the vehicle.
Page 15: Rear Axle
PARKING BRAKE Chevrolet dealer. Every 7,500 miles or 6 months clean and lubricate all parking brake pivot points with water resistant EP chassis lubricant which meets General Motors Specifica...
Page 16: Hood Latch And Hood Hinge
0-10 GENERAL INFORM ATION AND LUBRICATION bolts, lock striker plates, dovetail bumper wedges, etc. apply a thin film of light engine oil. Where oil holes are provided in body parts a dripless oil can be safely used, but any lubricant should be used sparingly, and after application all excess should be carefully wiped off.
Page 17: Air Vent Hose
GENERAL INFORMATION AND LUBRICATION 0-11 Fu ll Time Four Wheel Drive If differential is cold, fill to level of 1/2" below the filler plug hole. Add SAE 10W-30 or SAE 10W-40 engine oil to bring to level 1/ 2" below filler plug hole. For vehicles normally operated in Canada use SAE 80W GL-5 Gear Lubricant.
Page 18: Complete Maintenance Schedule
0-12 GENERAL INFORMATION AND LUBRICATION COMPLETE VEHICLE MAINTENANCE SCHEDULE Item When To Perform Services Services (Months or Miles, Whichever Occurs First) (For Details, See Numbered Paragraphs) Every 6 Months or 7,500 Miles *Chassis Lubrication •*F luid Levels Check *Engine Oil Change At 1st Oil Chg.
Page 19: Four Wheel Drive Models
GENERAL INFORMATION AND LUBRICATION 0-13 first 7,500 miles and then at every 15,000 miles EXPLANATION OF COMPLETE thereafter. Bias-belted tires should be rotated every VEHICLE MAINTENANCE 7,500 miles. To equalize wear, rotate tires as illustrated in Section 10 of this manual and adjust SCHEDULE tire pressures as shown on Tire Inflation Table in Presented below is a brief explanation of each of the...
Page 20 0-14 GENERAL INFORMATION AND LUBRICATION 13. SAFETY CHECKS TO BE PERFORMED BY indicated by a pull to the right or left when OWNER—The following checks should be made driving on a straight and level road. The need regularly during operation at no greater interval for wheel balancing is usually indicated by a than 6 months or 7,500 miles, whichever occurs vibration he steering wheel or seat while...
Page 21 GENERAL INFORMATION AND LUBRICATION 0-15 damaged glass on vehicle that could obscure DRUM BRAKES AND PARKING BRAKE- Check vision or become an injury hazard. drum brake linings and other internal brake components at each wheel (drums, wheel cylinders, (s) DOOR LATCHES-Check for positive closing, etc.).
Page 22 0-16 GENERAL INFORMATION AND LUBRICATION operation. Check hoses for cracking, abrasion or 33. SPARK PLUGS-Replace plugs at 22,500 mile intervals with type specified in Section 6 in this deterioration. Replace parts as necessary. manual. 27. CARBURETOR MOUNTING At 7,500, 22,500, and 45.000 miles, torque carburetor attaching bolts and/ 34.
Page 23 GENERAL INFORMATION AND LUBRICATION 0-17 RECOMMENDED FLUIDS & LUBRICANTS FLUID/LUBRICANT USAGE FLUID/LUBRICANT USAGE GM power steering fluid Hood hinges Engine oil Power steering system and pump reservoir Part No. 1050017 or equiv alent — if not available use Automatic transmission Engine oil DEXRON®-II automatic shift linkage...
Page 24 0-18 GENERAL INFORMATION AND LUBRICATION DRIVE O N HOIST BUMPER JA C K LIFTING I I I FLOOR JA C K OR HOIST LIFT Fig. 6— G Model Lifting Points www.PlandeGraissage.Org TRUCK SUPP • SERVICE...
Page 25 GENERAL INFORMATION AND LUBRICATION 0-19 Type of Lubrication Lubrication Points Q uantity Remarks Period Lubrication Lower Control Arms 7,500 Miles Chassis Lubricant 4 places as required Upper Control Arms 7,500 Miles Chassis Lubricant 4 places as required Upper and Lower Control Chassis Lubricant 4 places as required 7,500 Miles...
Page 26 0-20 GENERAL INFORMATION AND LUBRICATION Lubrication Type of Lubrication Points Q uantity Remarks Period Lubrication See Vehicle A ir Cleaner 15,000 Miles Maintenance Schedule Control Linkage Points 15,000 Miles Engine Oil As required Brush or Spray to applv 7,500 Miles Tie Rod Ends Chassis Lubricant 2 places as required...
Page 27 GENERAL INFORM ATION AND LUBRICATION 0-21 Lubrication Type of Lubrication Points Remarks Q uantity Period Lubrication Control Arm Bushings and Ball Joints 7,500 Miles Chassis Lubricant 12 places as required Tie Rod Ends 7,500 Miles Chassis Lubricant 4 places as required 2 fittin q s each side Wheel Bearings 30,000 Miles...
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Page 29 SECTION 1A HEATER AND AIR CONDITIONING C O N TE N TS OF THIS SECTION General Inform ation..............1 A-1 Air Conditioning................1 A-1 GENERAL INFORMATION Refer to the 1974 Light Duty Truck Service Manual for servicing the standard heater and auxiliary heater. AIR CONDITIONING Refer to the 1974 Light Duty Truck Service Manual for Refrigerant flows into the crankcase from the connector...
Page 30 1 A -2 HEATER AND AIR CO N D ITIO N ING 1. Screw 13. S u p e rh e a t Switch 24. B e lle v ille W ashe r 2. Locking W ashe r 14. O -R ing 25.
Page 31 HEATER AND AIR C O NDITIO NIN G 1A-3 9. Remove the condenser assembly by pulling it forward and then lowering it from the vehicle. 10. To install a new condenser, reverse Steps 1-9 above. Add one fluid ounce of clean refrigeration oil to a new condenser.
Page 32 1A-4 HEATER AND AIR CO NDITIO NING pillar and forward engine housing attaching screws. 17. To reassemble. Reverse Steps 1-16. Move rearward to gain access. 11. Disconnect vacuum lines and electrical connectors. AIR INLET VALVE - G MODEL Remove heater distributor duct assembly. Replacement 12.
Page 33 SECTION IB BODY NOTE: Except for the items listed below, all information found in section IB of the 1974 Light Duty Truck Service Manual is applicable to 1975 Light Duty Trucks. INDEX C-K Models..................IB-1 G Models.................... IB-3 C-K MODELS Fig.
Page 34 1 B -2 B O D Y Fig. 4— Wedge and Striker Adjustments CAUTIO N A D D E D - REAR DOOR CHECK STRAP ENDGATE DISASSEMBLY Model 06 Figure 3 shows the cloth check strap used for rear doors. Model 06 The door may be completely opened by removing the Refer to page IB-20 of the 1974 Light Duty Truck...
Page 35 B O D Y IB - 3 G MODELS Fig. 5— Remote Control and Latches REAR DOOR ITEMS Latches, Strikers and Wedges Figures 5 and 6 illustrate the new latches, strikers, wedges and adjustment dimensions for G-Model rear doors. Refer to pages IB-44 and IB-45 o f the 1974 Light Duty Truck Service Manual fo r replacement instructions.
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Page 37 SECTION 2 FRAME Truck frames are essentially carryover with some models dimension changes. The 10-30 series frames and related undergoing configuration and alignment reference dimensions are shown in figures 1 through 3. M o d e l C A107 15-1/4 13-3/8 19-7/8 17-3/4...
Page 38 2 -2 FR A M E www.PlandeGraissage.Org TRUCK SUPP - SERVICE...
Page 39 F R A M E 2 -3 www.PlandeGraissage.Org TRUCK SUPP - SERVICE...
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Page 41 SECTION 4 REAR SUSPENSION AND REAR AXLE NOTE: Except for the following items, all information found in Section 4 of the 1974 Light Duty Truck Service Manual is applicable to the 1975 Light Duty Trucks. INDEX Bushing Replacement............... 4-1 Universal Joint Repair..............4-1 Propshaft Phasing................
Page 42 4 -2 REAR S U S P E N S IO N A N D REAR AXLE TRUNNION SPACER J-9522-5 BEARING Fig. 2— Using Spacer to Remove Bearing Cup Fig. 4— Installing Trunnion into Yoke in production bearing cups. Discard all universal bearing retainers from the grooves in the yokes.
Page 43 REAR SUSPENSION AND REAR AXLE Fig. 7— Alignment Key AXLE SHAFT Fig. 6— Seating Snap Rings Remove and Reinstall 7. Continue to press until the opposite bearing Axles equipped with 8-7/8" ring gears and Eaton retainer can be snapped into place. If difficulty is Locking differentials use a thrust block on the pinion encountered, strike the yoke firmly with a hammer shaft which affects the removal of axle shafts as noted...
Page 44 4-4 REAR SUSPENSION AND REAR AXLE © VERTICAL PLACE FRONT YOKE OF REAR PROP SHAFT IN VERTICAL POSITION PLACE TRANSMISSION SLEEVE YOKE IN VERTICAL REAR PROP POSITION SHAFT ROTATE REAR SHAFT 4 SPLINES (90°) TOWARD L.H. SIDE INSTALL REAR SHAFT TO FRONT SHAFT Fig.
Page 45 REAR SUSPENSION AND REAR AXLE Fig. 12— Push Axle Shaft Inward Fig. 11— Correct C-Lock Position www.PlandeGraissage.Org TRUCK SUPP SERVICE...
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Page 47 SECTION 5 BRAKES The following caution 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 Caution on page 1 of this section". THIS FASTENER IS AN IMPORTANT ATTACHING C A U T IO N : PART IN THAT IT COULD AFFECT THE PERFORMANCE OF...
Page 48 5 -2 BRAKES 5. Place parking brake lever in fully released position. Adjustm ent Take up slack in brake linkage by pulling back on 1. Allow the pedal to return to its normally released cable just enough to overcome spring tension. position.
Page 49 BR AK ES 5 -3 P300 (32) MODELS G MODELS Fig. 3--Parking Brake Assembly -Typical tang of washer over reinforcement and side of Inspection washer over hex of anchor pin. Replace any worn or broken parts. See " Caution" on Page 1 o f this CA U TIO N : section.
Page 50 5-4 BRAKES Fig. 4 -Parking Brake System (Typical) www.PlandeGraissage.Org TRUCK SUPP ■ SERVICE...
Page 51 BRAKES lever assembled to it (automatic transmission), to 12. Place guide plate on anchor pin. the right (manual transmission). 13. Install pull back springs. 10. Pull brake shoes apart and install strut lever and 14. Remove the "knock out" plug (if necessary) and spring between them.
Page 52 5-6 BRAKES 4. Crank engine for 4 to 5 second intervals while pouring fluid into the reservoir. 5. Fill reservoir and crank as in step 4 until system will no longer accept fluid. It is normal that fluid may spill when cranking stops (it is the result of air in the system trying to escape).
Page 53 BRAKES Fig. 8- Booster Installation-Except P30(32) Models www.PlandeGraissage.Org TRUCK SUPP - SERVICE...
Page 54 5-8 BRAKES LIN K A G E BRACKET PEDAL PUSH ROD SUPPORT REAR BOOSTER PEDAL ROD LIN K A G E BRACKET FRONT SUPPORT PEDAL ROD VIEW B LEVER BOOSTER REAR SUPPORT VIEW VIEW C Fig. 9- Booster Installation-P30(32) Models Fig.
Page 55 BRAKES C MODELS M A N U A L S T E E R I N G P O W E R S T E E R I N G G MODELS TO GEAR FROM GEAR M A N U A L S T E E R I N G P O W E R P30 (32) MODELS P30 (42) MODELS...
Page 56 5-10 BRAKES DIAGNOSIS - HYDRO - BOOST SYSTEM NOTE: Before checking the hydraulic pow er booster for the source o f trouble, refer to the trouble diagnosis procedures for Standard Brakes. A fter these possible causes have been eliminated, check for the probable cause and remedy as outlined below: N o r m a l O p e r a t i n g C h a r a c t e r i s t i c s Brake pedal application o f the Hydro-boost system differs in some respects from a vacuum type power...
Page 57 BRAKES 5-11 DIAGNOSIS - HYDRO - BOOST SYSTEM SLOW BRAKE PEDAL RETURN Probable Cause Remedy Excessive seal f r i c t i o n in booster. Replace a l l booster seals. Faulty spool a ctio n . Clean spool and replace a l l booster seals. Broken piston return spring.
Page 58 12 BRAKES DIAGNOSIS - HYDRO-BOOST SYSTEM POWER STEERING PUMP NOISE ON BRAKE APPLY Probable Cause Remedy In s u f f i c ie n t f l u i d in pump Fluid level decreases approximately reservoi r . 1/2"...
Page 59 BRAKES 5-13 DIAGNOSIS - HYDRO - BOOST SYSTEM ACCUMULATOR LEA KDO W N - SYSTEM DOES NOT HOLD CHARGE P r e l i m i n a r y C h e c k S tart engine and tu rn the steering wheel u n til the wheels co ntact the wheel stops lig h tly . H old fo ra m axim um o f five seconds.
Page 60 SECTION 6 ENGINE MECHANICAL IN-LINE ENGINES INDEX Component Replacement and Adjustment........ 6-3 Exhaust Manifold Assembly............6-3 Removal.................... 6-3 Installation..................6-3 COMPONENT REPLACEMENT AND ADJUSTMENT 5. Disconnect exhaust pipe at manifold flange. 0 0 0 6. Remove manifold attaching bolts; then, remove manifold and discard gasket.
Page 61 ENGINE MECHANICAL V8 ENGINES INDEX General Inform ation...........;......6-1 Component Replacement and Adjustment....... 6-1 Intake M anifold................6-1 Crankcase Front Cover..............6-1 Installation..................6-1 Diagnosis....................6-2 GENERAL INFORMATION All light duty trucks will utilize a high energy ignition Except for the following changes, all information listed system for 1975.
Page 62 6-2 ENGINE '-JH DOWEL PIN (ONE AT EACH SIDE) Fig. 3R— Aligning Cover to Dowel Pins Fig. 2R— Installing Front Cover and Seal 6. Tighten screws alternately and evenly while using used to draw up cover and install remaining cover drift or other suitable tool to align dowel pins in screws.
Page 63 ENGINE d. Check engine operating temperature and correct as system as outlined in Section 6Y of this manual. necessary. Correct as necessary. e. Check the PCV system for satisfactory operation. i. Check carburetor for incorrect idle speed, defective Correct as necessary. altitude compensator, sticking choke or enrichment system and adjust, repair or replace as necessary.
Page 64 6 4 ENGINE Check engine operating temperature. Correct as Check, inspect and regap spark plugs. Replace as necessary. necessary. Check distributor spark advance mechanism for Check for loose, corroded or leaking wiring proper operation. Repair or replace as necessary. connections (bulk-head connectors etc.) Repair as necessary.
Page 65 ENGINE (pinched lines, faulty fuel tank cap or pick-up) and j. Check P.C.V. system operation and correct as correct as necessary. necessary. f. Check fuel pump operation and replace if k. Check for vacuum leaks and repair or replace as necessary.
Page 66 6-6 ENGINE NO OIL PRESSURE WHILE IDLING a. Check faulty oil gauge sending unit, and correct as c. Inspect for excessive clearance at main and necessary. connecting rod bearings and correct as necessary. b. Check for oil pump not functioning properly. d.
Page 67 ENGINE f. Check for improperly assembled piston pins. h. Inspect for engine overheating. Correct as Replace as necessary. necessary. i. Check for sub-standard fuel. Correct as necessary, g. Check for insufficient ring gap clearance. Correct as necessary. j. Check ignition timing. Correct as necessary. NO ISY C O N N E C TIN G RODS a.
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Page 69 SECTION 6M ENGINE FUEL C O N TE N TS OF TH IS SECTION 1MV Carburetor................6M-1 2GC Carburetor................6M-18 4MV Quadrajet Carburetor............6M-31 M4MC/M4MCA Carburetor............6M-31 Accelerator Control............... .6M-53 Air Cleaner..................6M-55 Fuel P u m p ..................6M-60 1 MV MONOJET CARBURETOR INDEX General Description............
Page 70 6M -2 ENGINE FUEL (Figure 1). If replacing float bowl, follow manufacturer’s head screw installed in the lower hole of the bracket. instructions contained in the service package so that the (Figure 2). identification number can be transferred to the new float The throttle return spring bracket bowl.
Page 71 ENGINE FUEL 6M -3 the float bowl. At this point, the float arm forces the float needle against the float needle seat, shutting off fuel TOP AIR BLEED TUBE TO * E.G.R (EXH AU ST GAS flow. As fuel is used from the float bowl, the float drops E .G .R .'V A L V E RE CIRC ULATIO N) downward, allowing the float needle to move off its seat...
Page 72 6 M -4 ENGINE FUEL dust cover over the valve chamber. A seal is used The same air bleed is used as an additional fuel feed at higher engine speeds to supplement main discharge between the compensator valve and float bowl casting. nozzle delivery during operation of the main metering In order to insure proper idle adjustment when the system.
Page 73 ENGINE FUEL 6M -5 metered and flows on into the main fuel well. In the main well the fuel is mixed with air from the air bleed at the top of the well and another air bleed which leads into the main well from the discharge nozzle cavity. M A I N P O W E R P IS T O N D IS C H A R G E...
Page 74 6M -6 ENGINE FUEL The accelerating pump is located at the side of the main fuel bowl, adjacent to the venturi area. It consists of a spring loaded pump plunger and pump return spring operating in a fuel well. The pump plunger is connected by linkage directly to a lever on the throttle shaft.
Page 75 ENGINE FUEL 6M -7 velocity through the air horn can continue to open the choke valve. This continues until the engine is warm. At this point the choke coil tension is completely relaxed and the choke valve is wide open. The fast idle cam has graduated steps so that fast idle engine speed is lowered gradually during the engine warm up period.
Page 76 6M -8 ENGINE FUEL turning 1/ 8" hex screw in end of solenoid on manual transmission. 8. Cut off tab on limiter cap. Do not remove cap from screw. Turn idle mixture screw counterclockwise until maximum idle speed is achieved. Reset idle speed to specified rpm, if required.
Page 77 ENGINE FUEL 6M -9 ✓ 'I ® ■ ' S G A U G E B E T W E E N L O W E R E D G E OF 1 ) W I T H F A S T ID L E A D J U S T M E N T M A D E , C A M F O L L O W E R OR F A S T ID L E S C R E W M U S T BE H E L D F IR M L Y O N...
Page 78 6 M -10 ENGINE FUEL AUXILIARY VA C U U M BREAK A D JU S TM E N T (Fig. 15) 1. Using an outside vacuum source, apply vacuum to auxiliary vacuum break diaphragm until plunger is fully seated. 2.
Page 79 ENGINE FUEL 6M-11 2. Remove inlet fuel filter nut from carburetor. 3. Remove filter element and spring. 4. Install element spring and filter element in carburetor. 5. Install new gasket on inlet fitting nut and install nut in carburetor and tighten securely. S P R I N G 6.
Page 80 6 M -1 2 ENGINE FUEL Fig. 18—Air Horn T ig h ten in g Sequence www.PlandeGraissage.Org TRUCK SUPP • SERVICE...
Page 81 ENGINE FUEL 6M -13 DIAGNOSIS 5. Engine compression. G E N ER A L When carburetor troubles are encountered they can 6. Ignition system firing voltage. usually be diagnosed and corrected with an adjustm ent as outlined below and under M aintenance and Adjustm ents. 7.
Page 82 6 M -1 4 ENGINE FUEL Problem: ENGINE CRANKS (TURNS OVER) BUT WILL NOT START OR STARTS HARD WHEN COLD. PO SSIB LE CAUSE CO R R E C TIV E ACTION Check proper starting, as o u tlin ed in the ow ner's m anual. Im p ro p e r starting p ro c ed u re used.
Page 83 ENGINE FUEL 6M -15 Problem: e n g in e s t a r t s a n d s t a l l s Check and re-set th e fast idle setting and fast idle cam . Engine does not have enough fast idle speed when cold. 1.
Page 84 ENGINE FUEL 6M -16 Problem: e n g in e r u n s u n e v e n o r s u r g e s PO SSIB LE CAUSE C O R R E C T IV E ACTIO N Fuel R es trictio n Check all hoses and fuel lines fo r bends, kin ks or leaks.
Page 85 ENGINE FUEL 6M -17 Problem: e n g in e h e s i t a t e s o n a c c e l e r a t i o n 1. R em ove air horn and check p u m p cup. If cracked, D efe c tiv e accelerato r p um p system scored or d is to rte d , replace th e p u m p plunger.
Page 86 6M -18 ENGINE FUEL 2GC CARBURETOR IN D E X General Description............6M-18 Service Operations............6M-24 Theory of Operation ............6M-18 Diagnosis................6M-26 Maintenance and Adjustment........6M-21 GENERAL DESCRIPTION CLEAN AIR TUBE AIR H O R N ACCELER ATO R CHOKE CLOSING PU M P ROD ASSIST.
Page 87 ENGINE FUEL 6M -19 the off-idle discharge ports are exposed to manifold its seat allowing more fuel to enter the bowl, thereby vacuum. These ports supply additional fuel mixture for keeping the fuel level constant. off-idle engine requirements. The fuel bowl is internally vented by a large drilled hole The fuel vapor collection canister is purged by ports which leads from inside the air horn bore to a vapor located in the carburetor throttle body.
Page 88 6M -20 ENGINE FUEL wells to provide smooth fuel flow for efficient metering. restrictions into the main fuel wells for desired This results in improved fuel control in the off-idle, enrichment at the main discharge nozzles. The power transfer, and part throttle range of operation. Air valve, located at the bottom of the fuel bowl, provides entering the main wells through the main well air bleeds the correct fuel enrichment for power requirements.
Page 89 ENGINE FUEL 6M-21 idle cam will drop from the high step to a lower step when the throttle is opened. The vacuum break unit is delayed in operation by an internal bleed check valve. The delay check valve slows down further opening of the valve a few seconds until the engine will run on slightly leaner mixtures.
Page 90 6 M -2 2 ENGINE FUEL 8. Adjust idle rpm to the higher of the two idle speeds IDLE SPEED specified. (Example 650/600). 1. With engine at normal operating temperature, air 9. Equally enrich (turn out) mixture screws until cleaner on, choke open, and air conditioning OFF, maximum idle speed is achieved.
Page 91 ENGINE FUEL 6M -23 5. Bend intermediate choke rod at point shown to adjust. A U TO M A TIC CHOKE COIL A D JU S TM E N T (Fig. 31) 1. Place idle speed screw on the highest step of fast idle cam.
Page 92 6 M -2 4 ENGINE FUEL 4. Hold choke coil lever inside choke housing towards the closed choke position. © G A U G E BETWEEN 5. Gauge between upper edge of choke valve and air UPPER EDGE OF horn wall. CHOKE VALVE A N D AIR HORN W ALL.
Page 93 ENGINE FUEL 6M -25 Fig. 3 4 — Fuel Filter R eplacem ent Fig. 3 5 —A ir H orn Tig h ten in g Sequence 2. Install new insulator. of engine power or rough (pulsating) engine feel, especially at high engine speeds. 3.
Page 94 ENGINE FUEL 6M -2 6 DIAGNOSIS 5. Engine compression. G EN ER A L When carburetor troubles are encountered they can usually be diagnosed and corrected w ith an adjustm ent as 6. Ignition system firing voltage. outlined below and under M aintenance and A djustm ents. 7.
Page 95 ENGINE FUEL 6M -27 Problem: ENGINE CRANKS (TURNS OVER) BUT WILL NOT START OR STARTS HARD WHEN COLD. C O R R E C T IV E ACTION PO SSIB LE CAUSE Check proper starting, as o u tlin ed in the ow ner's m anual. Im p ro p e r starting p rocedure used.
Page 96 6M -2 8 ENGINE FUEL Problem: e n g i n e s t a r t s a n d s t a l l s Engine does not have enough fast idle speed when cold. C heck and re-set th e fast idle setting and fast idle cam. C hoke vacuum break u n it is n o t ad justed to sp ecification 1.
Page 97 ENGINE FUEL 6M -29 Problem: e n g i n e r u n s u n e v e n o r s u r g e s PO SSIB LE CAUSE C O R R E C T IV E A CTIO N Fuel R es trictio n Check all hoses and fuel lines fo r bends, kin ks or leaks.
Page 98 6M -3 0 ENGINE FUEL Problem: e n g i n e h e s i t a t e s o n a c c e l e r a t i o n 1. R em ove air horn and check p u m p cup. If cracked, D efe ctive accelerator p u m p system scored or d is to rte d , replace th e p u m p plunger.
Page 99 ENGINE FUEL 6M-31 4MV QUADRAJET CARBURETOR The 1975 Non-California and California 350/400 V8 Refer to specifications section for 1975 4MV carburetor vehicle of 6200 pounds gross vehicle weight (G.V.W.) adjustment specifications. Refer to 1974 Light Duty and above will continue to use the basic 1974 4MV Truck Service Manual for service procedures, carburetor.
Page 100 6 M -3 2 ENGINE FUEL controlling air/fuel ratios during the part throttle throttle lever, to open the primary throttle valves slightly to lean out the rich air/fuel mixture in the range. intake manifold. The deceleration throttle stop On models designated M4MCA, a barometric pressure- vacuum unit requires new adjustment procedures.
Page 101 ENGINE FUEL 6M -33 located in the air horn. The purpose of the vertical vent low pressure area and the fuel in the float bowl vented to slot and vent tube is to balance air pressure acting on the atmosphere (high pressure), the idle system operates as fuel in the float bowl with air flow through the follows: carburetor bores.
Page 102 6 M -3 4 ENGINE FUEL cause low pressure at the lower idle air bleeds. As a Timed Bleed Purge result, fuel begins to discharge from the lower idle air The timed bleed purge port is located in each bore next bleed holes and continues to do so throughout operation to the off-idle discharge ports.
Page 103 ENGINE FUEL 6M 35 and the larger diameter of the metering rod is in the the high speed fuel feeds, supplementing fuel flow from main metering jet orifice. This results in leaner fuel the main metering system. The pull-over enrichment mixtures for economy operation.
Page 104 6 M -3 6 ENGINE FUEL The ports immediately start to feed fuel from the point, the vacuum break rod is in the forward end of the accelerating wells and continue to feed fuel until the fuel slot in the air valve lever and the air valves are closed. in the well is gone.
Page 105 ENGINE FUEL 6M -37 When the throttle valves are opened, the connecting lever comes to rest on the high step of the fast idle cam. linkage forces the pump plunger downward. The pump During engine cranking, the closed choke valve restricts cup seats instantly and fuel is forced through the pump air flow through the carburetor bores to provide a richer discharge passage where it unseats the pump discharge...
Page 106 6 M -3 8 ENGINE FUEL F R O N T V A C U U M B R E A K A D J U S T I N G S C R E W C H O K E V A L V E F R O N T V A C U U M C H O K E B R E A K...
Page 107 ENGINE FUEL 6M -39 Manifold vacuum to the rear vacuum break diaphragm valve lock-out pin. This allows the secondary throttle is controlled by a water temperature switch mounted in valves to open for hot engine power requirements. the engine cooling jacket near the front of the engine. The choke system is equipped with an unloader feature During cold operation when manifold vacuum is applied which is designed to open the choke valve partially,...
Page 108 6M -40 ENGINE FUEL to achieve the smoothest idle while maintaining emission levels within standards prescribed by Federal Law. At major carburetor overhaul the idle mixture may be adjusted. Before suspecting idle mixture as cause of poor idle quality, check ignition system, distributor, dwell and timing, air cleaner, PCV system, evaporation emission control and compression pressures.
Page 109 ENGINE FUEL 6M-41 AIR VALVE DASHPO T A D JU S T M E N T (Fig. 4 8 ) 1. Seat front vacuum break diaphragm using outside vacuum source. 2. Air valves must be closed completely. 3. Place specified gauge between air valve dashpot and end of slot in air valve lever.
Page 110 6M -4 2 ENGINE FUEL 5. Tighten retaining screws. 5. Place gauge between upper edge of choke valve and inside air horn wall. Dimension should be as specified. 6. To obtain correct specification, turn the adjustment screw on the vacuum break plunger lever. UNLOADER A D JU S TM E N T (Fig.
Page 111 ENGINE FUEL 6M -43 G A U G E B E T W E E N A I R N O T E : H O L D H O R N W A L L & U P P E R E D G E G A U G E O F C H O K E V A L V E V E R T I C A L L Y...
Page 112 6 M -4 4 ENGINE FUEL SECONDARY CLOSING A D JU S T M E N T (Fig. 54 ) 1. Pre-set carburetor speed screw to specifications. cOJ__IL r'i 2. Hold choke valve wide open with cam follower lever off steps of fast idle cam. 3.
Page 113 ENGINE FUEL 6M -4 5 AIR VALVE SPRING W IN D -U P A D JU S TM E N T (Fig. 56) 1. Remove front vacuum break diaphragm unit and air valve dashpot rod. 2. Loosen lock screw using special hex wrench. 3.
Page 114 ENGINE FUEL 6M -46 4. Connect downshift cable and adjust as required. 5. Connect accelerator linkage. 6. Connect fresh air hose and choke hose to choke system. 7. Connect fuel and vacuum lines. 8. Install air cleaner. 9. Refer to Maintenance and Adjustment and check idle speed.
Page 115 ENGINE FUEL 6M -47 DIAGNOSIS 5. Engine compression. GENERAL When carburetor troubles are encountered they can usually be diagnosed and corrected with an adjustment as 6. Ignition system firing voltage outlined below and under Maintenance and Adjustments. /. Ignition spark timing. Before diagnosing the carburetor as the trouble area, check and diagnose the following: 8.
Page 116 6 M -48 ENGINE FUEL Problem: ENGINE CRANKS (TURNS OVER) BUT WILL NOT START OR STARTS HARD WHEN COLD. CO RRECTIVE ACTION POSSIBLE CAUSE Check proper starting procedure, as outlined in the owner's Im proper starting procedure used. manual. Add fuel. Check fuel gauge for proper operation. N o fuel in gas tank Adjust the choke thermostatic coil.
Page 117 ENGINE FUEL 6M -49 Problem: e n g in e s t a r t s a n d s t a l l s Engine does not have enough fast idle speed when cold. Check and re-set fast idle cam. Choke vacuum break u n it is not adjusted to specification 1.
Page 118 6 M -5 0 ENGINE FUEL Problem: e n g in e r u n s u n e v e n o r s u r g e s POSSIBLE CAUSE C O R REC TIV E ACTION Fuel Restriction Check all hoses and fuel lines fo r bends, kinks or leaks.
Page 119 ENGINE FUEL 6M -51 NO POWER ON H E A V Y A C C E LE R A TIO N OR A T H IG H SPEED POSSIBLE CAUSE CO RRECTIVE ACTION Lubricate thro ttle linkage to obtain wide open th ro ttle in C arburetor th ro ttle valve not going w ide open.
Page 120 6M -52 ENGINE FUEL Problem: p o o r f u e l e c o n o m y POSSIBLE CAUSE CO RRECTIVE ACTION Engine needs com plete tune-up. Check engine compression. Exam ine spark plugs, (if d irty or im properly gapped, clean and re-gap or replace).
Page 121 ENGINE FUEL 6M -53 ACCELERATOR CONTROL GENERAL H AND THRO TTLE CO N TR O L The accelerator control system is cable type. There are Refer to figure 63 for hand throttle controls for CK no linkage adjustments. A reference between the bottom vehicles.
Page 122 6 M -5 4 ENGINE FUEL 1 NOTE [ S l i p a c c e l e r a t o r c o n t r o l c a b l e RADIO BRACKET t h r u s l o t in Rod. I n s t a l l r e t a i n e r , be in g s u r e i t is s e a t e d .
Page 123 ENGINE FUEL 6M -55 NOTE: Slip acce lera tor control cable thru slot in rod. Install retainer, being sure it is seated. CABLE RETAINER CAUTION: Care must be used in pressing the retainer into hole in rod to assure cable is not kinked or dam aged in any w a Y- REINFORCEMENT...
Page 124 6M -56 ENGINE FUEL AIR BLEED VALVE VIEW B— UNDERHOOD TEMPERATURE VIEW A—ENGINE OFF CLOSED BELOW 85°F DIAPHRAGM SPRING TEMP. SENSING DIAPHRAGM SPRING SPRING VACUUM CHAMBER SNORKEL TUBE VACUUM CHAMBER SNORKEL TUBE LINKAGE — DIAPHRAGM DIAPHRAGM CONTROL DAMPER ASSM. ' f f HOT AIR PIPE CONTROL DAMPER ASSM.
Page 125 ENGINE FUEL 6M -57 Fig. 70— Cleaning Polywrap Band 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). AIR CLEANER Refer to figure 71 for air cleaner used with in line L6 engine.
Page 126 6 M - 5 8 E N G IN E FUEL W IN G NUT GASKET (P O S ITIO N RED SURFACE D O W N ) EXTENSION G 1 0 - 3 5 0 V 8 2Bbl. G A S K E T ------ -------- (P O S IT IO N RED SURFACE D O W N ) Fig.
Page 127 ENGINE FUEL 6 M -59 door should remain in position (closed snorkel passage). If it does not, there is a vacuum leak in diaphragm assembly. Replace diaphragm assembly. 5. If vacuum motor check is found satisfactory, TOOL J-22973 replace sensor unit. Vacuum M otor Replacem ent Removal 1.
Page 128 ENGINE FUEL 6M -60 2. Press retaining clip on sensor. Support the sensor CARBURETOR AIR IN TA K E on its sides to prevent damage to the control • • . i > a Refer to figure 79 for carburetor air intake used on CK mechanism at the center.
Page 129 ENGINE FUEL 6M-61 4 B B L . C A R B U R E T O R B B L . C A R B U R E T O R PUSH ROD GASKET PLATE GASKET TIGHTEN TO 27 FT. LBS. TIG HTEN TO 36 IN.
Page 130 ENGINE FUEL 6M -62 FUEL PUMP DIAGNOSIS 3. With engine idling (using fuel in the carburetor float CAMSHAFT DRIVEN FUEL PUMP bowl), the vacuum should be at least 12” Hg. Complete diagnosis of all possible causes of the trouble 4. If the vacuum is less than 12" Hg., replace pump. If prior to replacement of the fuel pump will save time, expense the vacuum is okay, proceed to the next test.
Page 131 SECTION 6T EMISSION CONTROL SYSTEMS C O N TE N TS OF THIS SECTION NOTE: Except for the following changes, all information listed in Section 6T of the 1974 Truck Service Manual is applicable to 1975 light duty trucks. Refer to 1974 Truck Service Manual for any service procedures not contained herein.
Page 132 EMISSION CONTROL SYSTEMS 6T-2 THROTTLE RETURN CONTROL SYSTEM vacuum to operate the throttle lever actuator. The A throttle return control system (TRC) is also throttle lever actuator then pushes the throttle lever used on some California Truck engines. slightly open, thus reducing the hydro-carbon emission during coast down.
Page 133 EMISSION CONTROL SYSTEMS 6T-3 e. If the RPM obtained in step 3 d is not within c. Recheck the valve set point per steps No. 3 and 150 RPM of that obtained in step 3c, then the actuator plunger may be binding due to dirt, d.
Page 134 www.PlandeGraissage.Org...
Page 135 SECTION 6Y ENGINE ELECTRICAL NOTE: Except for the following changes, all information listed in Section 6Y of the 1974 Truck Service Manual is applicable to 1975 light duty trucks. Refer to 1974 Truck Service Manual for any service procedure not contained herein. 10-SI SERIES GENERATOR The 1975 10-SI generator is mostly carryover from 1974.
Page 136 6Y-2 ENGINE ELECTRICAL STARTER SYSTEM The 1975 starter is mostly carryover from 1974. The only difference being that the "R " terminal of the starter solenoid has been removed. This terminal was removed because with the High Energy Ignition System there is no longer any requirement for the electrical lead from the starter solenoid to the ignition coil.
Page 137 ENGINE ELECTRICAL 6Y-3 true transformer with the windings surrounded by the laminated iron core. A conventional coil has the iron IG N IT IO N COIL CONNECT TACHOMETER core inside the windings. Although the HEI coil operates FR OM THIS TERMINAL in basically the same way as a conventional coil, it is TO G R O U N D .
Page 138 5Y-4 ENGINE ELECTRICAL Fig. 3i— High Energy Ignition Basic Wiring SERVICE OPERATIONS Routine M aintenance Tachom eter Connections The HEI system is designed to be free from routine In the distributor cap connector is a "tach" terminal. maintenance. If component part replacement should Connect the tachometer to this terminal and to ground.
Page 139 ENGINE ELECTRICAL 6Y-5 6. Adjust ignition timing as described in Specification CYL NO. 6 CYL NO. 5 Section of this manual. CYL NO. 4 CYL NO. 3 CYL NO. 2 Distributor Disassembly and Assembly -CYL NO. 1 Disassembly (Figs. 6i — 8i) 1.
Page 140 6Y-6 ENGINE ELECTRICAL V A C U U M U N I T ADVANCE W EIGHT (2) A T T A C H I N G S C R E W S SPRING (2) T H I N " C ” C A P A C I T O R W A S H E R P I C K U P...
Page 141 ENGINE ELECTRICAL 6Y-7 Ignition Coil—8 Cylinder Rem oval (Fig. lO i) 1. Disconnect battery wire and harness connector from distributor cap. COVER 2. Remove three screws securing coil cover to distributor cap. 3. Remove four screws securing ignition coil to distributor cap.
Page 142 6Y-8 ENGINE ELECTRICAL HIGH ENERGY IGNITION SYSTEM D I A G N O S I S C H A R T S U sin g the C h a r t s In tr o du ctio n This section presents a system atic m ethod of diag The charts are divided into three sections: step, nosing and troubleshooting the High Energy Ig...
Page 143 ENGINE ELECTRICAL 6Y-9 HIGH ENERGY IGNITION SYSTEM PROBLEM: 3 - W I R E engine CRANKS but C O N N E C T O R C O I L WILL NOT START R O T O R ( 6 P I C K - U P C O I L M O D U L E STEP...
Page 144 6Y-10 ENGINE ELECTRICAL HIGH ENERGY IGNITION SYSTEM SEQUENCE RESULT STEP ------ ( YES )------------- DETERMINE IF MODULE TESTER WILL TEST BOTH PICKUP COIL AND MODULE WHILE CRANKING MODULE I--------- --------- 1 N O TESTER TEST PICKUP COIL AND MODULE PER IF OK TESTER M A N U ...
Page 145 ENGINE ELECTRICAL 6Y-11 HIGH ENERGY IGNITION SYSTEM CONNECT OHMMETER REPEAT STEPS 10 A N D 11 ACROSS 2 LEADS WHILE M O V IN G VAC. ADVANCE WITH SCREW READS 500 TO DRIVER. IF READING. 1500 OHMS IS STILL OK RUNS SMOOTH DOES NOT READ REPLACE COIL...
Page 146 ENGINE ELECTRICAL HIGH ENERGY IGNITION SYSTEM PROBLEM: engine RUNS ROUGH or CUTS OUT SEQUENCE STEP RESULT ( § > ----------------------------------- ® - r - j RUNS SMOOTH CHECK SPARK ^ r - ---- --------------------------------- PLUGS & PLUG WIRES REPAIR OR --------- REPLACE RUNS ROUGH...
Page 147 ENGINE ELECTRICAL 6Y-13 HIGH ENERGY IGNITION SYSTEM REMOVE GREEN & WHITE LEADS FROM MODULE STARTS REPLACE COIL J£f1. TH A N IN F IN IT Y (PICK UP) (X 1000 SCA LE ) CONNECT ------------ NO START OHMM ETER FROM --------- GROUND TO EITHER READS IN F IN IT E...
Page 148 6Y-14 ENGINE ELECTRICAL DIAGNOSIS CHARTS DELCOTRON GENERATOR Introduction Using the Charts This section presents a systematic method of diag The charts are divided into three sections: step, nosing and troubleshooting the Delcotron Gen sequence and result. erator system. The charts you will be using are STEP SEQUENCE RESULT...
Page 149 ENGINE ELECTRICAL 6Y-15 PROBLEM: generator light ON engine RUNNING GENERATOR FUSE BLOCK BELT SEQUENCE RESULT G E N E R A T O R L IG H T O FF RE PLA CE IF GO TO NEC E SSA R Y STEP 2 CHECK ADJUST...
Page 150 ENGINE ELECTRICAL 6Y-1 www.PlandeGraissage.Org TRUCK SUPP ■ SERVICE...
Page 151 ENGINE ELECTRICAL 6Y-17 www.PlandeGraissage.Org TRUCK SUPP - SERVICE...
Page 152 6Y-18 ENGINE ELECTRICAL Chart 4 C O I L C A R B U R E T O R G E N E R A T O R ( 1 B A T T E R Y PROBLEM: battery UNDERCHARGED G E N E R A T O R B E L T STEP...
Page 153 ENGINE ELECTRICAL 6Y-19 STEP SEQUENCE RESULT C O N N E C T P LAC E C A R B . V O L T M E T E R ON H IG H STEP ACROSS FA ST ID LE CA M B A T T E R Y D ISC O N N E C T C O IL JU M PE R...
Page 154 6Y-20 ENGINE ELECTRICAL 9 )C A R B U R E T O R G E N E R A T O R ^ 1 b a t t e r y PROBLEM: battery OVERCHARGED (uses too much water) RESULT SEQUENCE B A T T E R Y O K TEST B A T T E R Y...
Page 155 SECTION 7A AUTOMATIC TRANSMISSION C O N TE N TS OF THIS SECTION Turbo Hydra-Matic 350 Transmission........7A-1 Turbo Hydra-Matic 400/475 Transmission......7A-5 TURBO HYDRA-MATIC 350 TRANSMISSION INDEX General Description................7A-1 Vacuum Modulator Assembly...........7A-1 Maintenance and Adjustments...........7A-2 Transmission Fluid...............7A-2 Draining and Refilling Transmission.......
Page 156 7A-2 AUTOMATIC TRANSM ISSIO N MAINTENANCE AND ADJUSTMENTS lever until it locks into mechanical stop in the TR A N SM IS SIO N FLUID column assembly. Draining and Refilling Transm ission NOTE: Do not use indicator pointer as a reference The oil pan should be drained and the strainer cleaned to position the shift lever.
Page 157 AUTOM ATIC TR AN SM ISSIO N 7A-3 V-8 ENGINE SNAP LOCK ASSEMBLED L-6 ENGINE CAUTION: Flexible components (hoses, wires, conduits, etc) must not be routed w ithin 2 inches o f moving parts of accelerator linkage forward of the Bracket unless routing is positively controlled.
Page 158 7A-4 AUTOMATIC TRANSM ISSIO N SNAP LOCK SNAP LOCK C - K AND P MODELS Fig. 4 G — D e te n t D ow nshift C able • C-K and P Series www.PlandeGraissage.Org TRUCK SUPP - SERVICE...
Page 159 AUTOM ATIC TR AN SM ISSIO N 7A-5 DIAGNOSIS drive, 166 psi in LI or L2, and 254 psi in reverse for the 350 V-8. While vehicle is stationary (service brake on), engine speed set to maintain 12 inches hg. absolute manifold pressure, transmission oil pressure gauge attached, and vacuum modulator tube connected, the transmission should read 85 psi in drive, 105 psi in LI or L2, and 129...
Page 160 7A-6 AUTOMATIC TRANSM ISSION with the first idle open throttle application of the accelerator pedal. PLUNGER PLUNGER REAR SEAL TRANSMISSION CONTROL Removal SWITCH 1. Remove propeller shaft. 2. Pry seal out with screw driver. Installation- P30 (42) SERIES All Models Except CL 1.
Page 161 SECTION 7M CLUTCHES & MANUAL TRANSMISSIONS C O N TE N TS OF TH IS SECTION Clutch Controls................7M-1 Manual Transmissions..............7M-3 CLUTCH CONTROLS INDEX General Description (G Model)..........7M-1 GENERAL DESCRIPTION The clutch operating controls for "G " models (fig. IT) pedal is depressed, the pedal pull rod moves rotating the are a mechanical type consisting of a pendant type cross shaft, pushing the clutch fork rod rearward and...
Page 162 7M -2 TRANSM ISSIONS Fig. IT — Clutch Linkage Assembly - G Models www.PlandeGraissage.Org TRUCK SUPP ■ SERVICE...
Page 163 TR ANSM ISSIO N S 7M -3 MANUAL TRANSMISSIONS INDEX Service Operations................. 7M-3 Transfer Case Replacement............7M-3 SERVICE OPERATIONS TRANSFER CASE REPLACEM ENT (Figs. 1Q- Installation 1. Support transfer case in suitable stand and position 3Q ) case to transmission adapter. Install bolts attaching case to adapter and torque to 45 ft.
Page 164 7 M -4 TRANSM ISSIONS AUTOMATIC TRANSMISSION WITH 4-SPEED TRANSMISSION WITH MODEL 203 TRANSFER CASE MODEL 205 TRANSFER CASE AUTOMATIC TRANSMISSION WITH 3-SPEED TRANSMISSION WITH MODEL 205 TRANSFER CASE MODEL 20 TRANSFER CASE K105 (FULL TIME) SUPPORT AND BRACKET ASSEMBLY (ALL MODELS) Fig.
Page 165 TR ANSM ISSIO N S 7M -5 In d ic a to r to be lo c a te d a t d e p re s s io n S h ift p a tte rn s h o u ld be in h o r iz o n ta l p o s itio n d r iv e r CARPET OR M A T N o in s u la tio n to be in s ta lle d...
Page 166 7M -6 TRANSM ISSIONS NOTE: Install Boot NOTE: No insulation prior to installation of to be installed under Nut & Knob. retainer NOTE: No insulation NOTE: With trans case in to be installed under 2 wheel “ H i" position, align Retainer.
Page 167 SECTION 8 FUEL TANK AND EXHAUST SYSTEM C O N TE N TS OF TH IS SECTION ............8-1 Exhaust System........Fuel Tank FUEL TANK Refer to the 1974 Light Duty Truck Service Manual for servicing of the fuel tank, fuel line and evaporation control system with the following exception: COMPONENT PART REPLACEMENT P MODELS AND 1 TON...
Page 168 8-2 FUEL TANK AND EXHAUST SYSTEM COMPONENT PART REPLACEMENT GENERAL Exhaust System Pipes and Resonators Rearward of the M ufflers Must Be Replaced W henever A New M uffler Is Installed. NOTE: When a muffler is replaced use sealing compound at the clamped joint to prevent leaks. New clamp released for 1975 is designed to make an indentation in the exhaust pipe for improved retention.
Page 169 FUEL TANK AND EXHAUST SYSTEM CONVERTER HEAT SHIELD CK 10 Model Refer to Figures 2 and 3 for converter heat shields. CATALYTIC CONVERTER (FIGS. 4 and 5) C K10 Model Removal 1. Raise vehicle on hoist. 2. Remove clamps at front and rear of converter. 3.
Page 170 8-4 FUEL TANK AND EXHAUST SYSTEM 5. Install empty catalyst container to converter (Fig. 6. Disconnect air supply to aspirator and connect air supply to vibrator. Catalyst will now drain from the converter into the empty container. 7. When all the catalyst has been removed from the converter, disconnect air supply to vibrator and remove container from the converter.
Page 171 FUEL TANK AND EXHAUST SYSTEM 7. Apply an anti-seize compound to the fill plug; 6. Install cover retaining channels on both sides of the converter (Fig. 16). install and tighten to 50 ft. lbs. 7. Attach 2 clamps over retaining channels at each end of the converter (Fig.
Page 172 8-6 FUEL TANK AND EXHAUST SYSTEM Fig. 14— Catalytic Converter Inner Shell Fig. 16— Installing Bottom Cover Retaining Channels INSULATION SEALING COMPOUND Fig. 15— Installing Bottom Cover Replacement Fig. 17— Installing Bottom Cover Clamps www.PlandeGraissage.Org TRUCK SUPP ■ SERVICE...
Page 173 FUEL TANK AND EXHAUST SYSTEM DIAGNOSIS EXHAUST SYSTEM C O N D IT IO N P O S S IB L E C A U S E C O R R E C T IO N Leaking Exhaust Gases Leaks at pipe joints. Tighten U -bolt nuts at leaking jo ints to 30 foot-pounds.
Page 174 8-8 FUEL TANK AND EXHAUST SYSTEM SPECIAL TOOLS 1. J-25077-1 Vibrator— Include Catalyst Container and Fill Tube Extension 2. J-25077-2 Aspirator Fig. 1ST— Special Tools www.PlandeGraissage.Org TRUCK SUPP ■ SERVICE...
Page 175 M U S T performed as outlined in the 1974 Chevrolet Passenger Car and Light Duty Truck Overhaul Manual, Section 9. POWER STEERING GEAR Adjustment of the power steering gear in the vehicle is...
Page 176 9-2 STEERING ADJUSTMENT HOLE ADJUSTMENT POWER HOLE POWER ADJUSTMENT STEERING STEERING BOLT PUMP PUMP ADJUSTMENT LOWER ADJUSTMENT BOLT P 30 MOTOR HOME WITH 4 54 V -8 C -K -G 1 0 -2 0 -3 0 L6 P 2 0 -3 0 L6 POWER STEERING PUMP ADJUSTMENT ADJUSTMENT BO...
Page 177 STEERING Figure 3 shows the latest linkage used on the G-Series TIE RODS truck and the P-Series, Motor Home models. Service procedures for the 1975 tie rod assemblies are identical to those outlined in the 1974 Light Duty Truck IDLER ARM Service Manual, Section 9.
Page 178 9-4 STEERING CLAMPING INSTRUCTIONS FO R ALL LIGHT TRUCKS. A ll b o lts must be in s ta lle d in CAUTION: CLAM PS MUST BE d ire c tio n shown. BETW EEN AND CLEAR O F DIMPLES Rotate both in n er and outer t ie BEFORE TORQUING NUT.
Page 179 STEERING POWER STEERING SYSTEM POWER STEERING P U M P (Fig. 6) Installation 1. Position pump assembly on vehicle (Fig. 6) and install attaching parts loosely. Removal 2. Connect and tighten hose fittings. 1. Disconnect hoses at pump. When hoses are 3.
Page 180 9-6 STEERING Fig. 7 —Power S teering Hose R outing TRUCK SUPP • SERVICE www.PlandeGraissage.Org...
Page 181 Hose must be located as shown within + 15 of port C/L FW D V IE W C V IE W A Rotate hose assembly to rest against steering gear housing cover. G 3 0 C U T A W A Y V A N CK S E R IE S L-6 A N D 3 5 0 V -8 W IT H 3 5 0 V -8 W IT H H Y D R O B O O S T...
Page 182 9-8 STEERING 1. PUMP PULLEY REMOVER J -2 5 0 3 4 2. PUMP PULLEY INSTALLER J -2 5 0 3 3 Fig. 10— Special Tools. www.PlandeGraissage.Org TRUCK SUPP • SERVICE...
Page 183 SECTION 10 WHEELS AND TIRES The 1975 wheel and tire maintenance and service ATTACHMENT OF DUAL WHEELS operations remain essentially the same as outlined in the ON P300 MODELS 1974 Truck Service Manual. Minimum Tire Inflation Pressure Tables and additional information for torquing dual wheels on P300 models have been revised as listed To assure secure attachment of the dual disc wheels, it is below to 1975 specifications.
Page 184 10-2 WHEELS AND TIRES TIRE LOAD & INFLATION PRESSURE PASSENGER TYPE TIRES FOR LIGHT TRUCKS USED IN HIGHWAY SERVICE Tire Load Limits at Various Inflation Pressures Tire Range Size Load E78-15 1030 1080 1130 1180 1230 1270 F78-15 1060 1110 1160 1220 1270...
Page 185 WHEELS AND TIRES 10-3 TIRE LOAD AND INFLATION PRESSURE TIRES FOR LIGHT TRUCKS USED IN HIGHWAY SERVICE (Cont’d) WIDE BASE TU B ELESS TIRES USED AS DUALS Tire Load Lim its at V arious Inflation P re ssu re s Tire Load Size...
Page 186 10-4 WHEELS AND TIRES MINIMUM TIRE INFLATION PRESSURE AT GROSS VEHICLE WEIGHT RATING (GVWR) (Lbs.) Load Range Replaces Ply Rating C, K 105 UTILITY K1Q , 15 P IC K U P K 10, 15 S U B U R B A N P 1 0 ,1 5 2 WHEEL DRIVE 4 WHEEL DRIVE...
Page 187 W H E E L S A N D T IR E S 1 0 -5 M I N I M U M T I R E IN F L A T I O N P R E S S U R E A T G R O S S V E H IC L E W E I G H T R A T IN G ( G V W R ) ( L b s . ) &...
Page 188 10-6 WHEELS AND TIRES M IN IM U M TIRE INFLATION PRESSURE AT GROSS VEHICLE W EIGHT RATING (GVWR) (Lbs.) CHEVY VAN G11005 G11305 G21005 G21305 G31005 G11005 G11305 7700 8100 4900 5400 5600 5600 6400 6400 6400 6900 7100 GVWR (Lbs.) 4800 5400...
Page 189 SECTION 11 CHASSIS SHEET METAL INDEX Carburetor Air Inlet Snorkels-CK Series..... General Description.............. 11-1 11-1 ........11-1 Rear Fender - CK Series.......... 11-2 M aintenance and Adjustm ents Hood Lock Assembly-CK Series......11-1 Running Board - CK Series........11-2 GENERAL DESCRIPTION The service procedures for all 1975 truck chassis sheet 1974 Light Duty Truck Service Manual, Section metal are essentially the same as those outlined in the...
Page 190 11-2 CHASSIS SHEET METAL SNORKEL LOCATION L6 SNORKEL Fig. 2 —C a rb u re to r O utside A ir In let Snorkels—CK Fig. 3 —R ear Fender an d B race—CK Series Series Installation Reverse removal procedure to install snorkel. Rear Fender CK-Series Refer to Figs.
Page 191 SECTION 12 ELECTRICAL-BODY AND CHASSIS NOTE: Except for the following changes, all information listed in Section 12 of the 1974 Light Duty Truck Service Manual is applicable to 1975 light duty trucks. Refer to 1974 Light Duty Truck Service Manual for any service procedure not contained herein.
Page 192 12-2 ELECTRICAL-BODY AND CHASSIS opening as one solid line. To remove "backlash" abnormally sloped, it may require that different readings be used for each side of the vehicle. In make final adjustment by turning horizontal adjusting screw in a clockwise direction. this instance, determine the floor level for BOTH sides of the vehicle.
Page 193 ELECTRICAL-BODY AND CHASSIS 12-3 H O R I Z O N T A L DI AI VERTICAL DIAL L O C K I N G H A ND LE FLOOR SLOPE K N O B FLOOR SLOPE LEVEL V I A l VERTICAL K N H O R IZ O N T A L K N O B S U C T I O N CUP...
Page 194 12-4 ELECTRICAL-BODY AND CHASSIS AIMER J-25300-2 AIMER J-25300-2 AIMER J-25300-1 PORT TARGETS MUST FACE EACH OTHER SIGHT OPENING LEVEL [FLOOR SLOPE ADAPTER! jj-25300-6 RIGHT SIDE SHOWN. LEFT SIDE J-25300-2 GOES IN REAR AND J-25300-1 IN FRONT. RIGHT SIDE SHOWN AIM EJ2 J-25300-1 Fig.
Page 195 ELECTRICAL-BODY AND CHASSIS 12-5 ' CIRCULAR HEADLAMP RECTANGULAR HEADLAMP ADAPTER J-25300-4 ADAPTER J-25300-3 CIRCULAR HEADLAMP ADAPTER J-25300-5 Fig. 5 —H e a d la m p A dapters HEADLAMP ADAPTER LEVEL VIAL VIEWING PORT HEADLAMP AIMER HEADLAMP AIMER J-25300-1 J-25300-2 Fig.
Page 196 12-6 ELECTRICAL-BODY AND CHASSIS SERVICE OPERATIONS HEADLAM PS W A R N IN G BUZZER Replacement (Fig. 7) 1. Pull headlamp warning buzzer from LPS (Lamps) socket of fuse panel. 2. Disconnect electrical connector from ACC (Accesso ries) of fuse panel. 3.
Page 197 SECTION 13 RADIATOR AND GRILLE INDEX ............13-1 Grille.................. 13-2 General Description ........13-1 Coolant Recovery System.......... 13-2 M aintenance and Adjustm ents. Radiator Replacement..........13-1 GENERAL DESCRIPTION All service procedures outlined in the 1974 Light Duty are essentially the same for 1975 with the exception of Truck Service Manual, Section 13, Radiator and Grille the following items.
Page 198 13-2 RADIATOR AND GRILLE GRILLE SERVICE PROCEDURES D 4 D IA T O R GRILLE UPPER P A N E L Grille ■ CK Series (Fig. 2) Removal H O O D L O C K SUPPORT 1. Remove the six (6) screws retaining grille to brackets and support assembly.
Page 199 SECTION 15 ACCESSORIES NOTE: Except for the following changes, all information listed in Section 15 of the 1974 Light Duty Truck Service Manual is applicable to 1975 light duty trucks. Refer to 1974 Light Duty Truck Service Manual for any service procedure not contained herein. CRUISE MASTER INDEX General Description............
Page 200 15-2 ACCESSORIES 3. When released slowly from the fully depressed CRUISE M ASTER U N ITS position, it will engage the system at the existing speed and cruise at that speed (above 30 mph). Figures 3C and 4C show the units in the installed position on the vehicles.
Page 201 ACCESSORIES 15-3 on the brake pedal bracket, disengages the system pneumatically when the brake pedal is depressed. E N G A G E H O L D 6. The Cable and Casing Assemblies drive the T E R M I N A L T E R M I N A L regulator and speedometer.
Page 202 15-4 ACCESSORIES An inoperative switch must be replaced. Switch change cruise speed approximately one mph. Snug- up lock nut after each adjustment. replacement procedure is similar to standard brake lamp switch replacement. If a Regulator is found to be defective and not simply Vacuum out-of-adjustment, it must be replaced.
Page 203 ACCESSORIES 15-5 CRUISE CONTROL CONTROL CABLE ADJUSTMENT VACUUM HOSE With Cable installed to Cable Bracket and Carburetor, install Cable to Servo Bracket. Using second ball on SERVO BOOT Servo Chain, install Servo Chain on Cable. With throttle completely closed ( ignition off and fast idle Cam off) adjust Cable Jam Nuts until Servo Chain is almost tight ( some slack).Tighten Jam Nuts to specified torque, then remove plastic retainer ( not shown) ( used to...
Page 204 15-6 ACCESSORIES F W D B R A K E P ED AL IN N O R M A L POSITION B R A K E P ED AL P O S I T I O N ^ .38 TO .64 WHEN V A C U U M V A L V E OPENS IN S T A L L A T IO N OF S E LF-A D JU S TIN G...
Page 205 ACCESSORIES 15-7 COMPONENT PART REPLACEMENT CO LUM N M O U N TE D E N G A G EM EN T REGULATOR SW ITCH Replacement Removal 1. Disconnect battery ground cable. 1. Disconnect the battery ground cable. 2. Disconnect speedometer cables at regulator. 2.
Page 206 15-8 ACCESSORIES NOTE: When disconnecting or reconnecting the Engagem ent Switch Test main wiring harness connector from the Regulator, care should be exercised so as not to damage the Check engagement switch and connecting wiring as blade connectors or the wiring harness. The follows: Unplug engagement switch connector (brown, disconnect may be facilitated by prying carefully blue, black) at electrical wiring harness connector then...
Page 207 E N G A G E M E N T SWITCH ( S H O W N I N " R E S T " P O S I T I O N ) CR U ISE RELEA SE V A L V E ---------------- i ^ 3 B R O W N...
Page 208 15-10 ACCESSORIES CRUISE MASTER TROUBLESHOOTING CHECK I FOR SYSTEMS WITH ERRATIC CRUISE PERFORMANCE CHECK II FOR INOPERATIVE SYSTEMS MAKE ALL TESTS WITH TRANSMISSION SELECTOR IN ''PARK'' & PARKING BRAKE ON EXCEPT WHERE INDICATED OTHERWISE. RECONNECT ANY DISCONNECTED HOSES AND/OR ELECTRICAL CONNECTORS IN PROPER MANNER AT THE COMPLETION OF TEST.
Page 209 ACCESSORIES 15-11 C H ECK n Fig. 9C~System Diagnosis Chart No.2 TRUCK SUPP ■ SERVICE www.PlandeGraissage.Org...
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Page 211 AUTOMATIC TRANSMISSION CLUTCH AND MANUAL TRANSMISSION MANUAL CHEVROLET MOTOR DIVISION STEERING GEAR, POWER STEERING G e n e ra l M o to rs C o rp o ra tio n PUMP AND GEAR D E T R O IT , M IC H IG A N SPECIFICATIONS —...
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Page 213 SECTION 1 AIR CONDITIONING C O N TE N TS OF TH IS SECTION Axial Six-Cylinder Compressor............. 1-1 Radial Four-Cylinder Compressor..........1-1 Special Tools..................1-13 AXIAL SIX-CYLINDER COMPRESSOR Refer to 1974 Overhaul Manual for overhaul procedures Use only refrigeration oil, not petroleum jelly, when on the axial six-cylinder compressor.
Page 214 1-2 AIR CONDITIONING Screw 13. S u p e rh e a t Switch 24. B e lle v ille W a sh e r 2. Locking W ashe r 14. O -R ing 25. O -R ing 3. P ulley Rim 15.
Page 215 AIR CO N D ITIO N IN G DISCHARGE SUCTION PORT PORT J9401 SUPERHEAT SWITCH CLUTCH PLATE AND HUB ASSEMBLY HIGH PRESSURE RELIEF VALVE Fig. 2 — In s tallin g H oldin g Fixture J-2 5 0 3 0 J -9 3 9 9 CLUTCH ASSEMBLY Fig.
Page 216 itmm 1-4 AIR CONDITIONING J -9 4 8 0 -1 J -9 4 8 0 -2 AIR G A P (.0 2 0 " — .0 4 0 " ) Fig. 6 — Installing Clutch P la te an d H ub Assem bly tighten center screw to press hub onto shaft until there is a .020 to .040 inch air gap between the frictional surfaces of clutch plate and clutch rotor...
Page 217 AIR CO NDITIO NING J-22974 and "O" ring installer J-21508 are clean 6. Install new seal seat retainer ring with snap ring internally and externally. The seal seat "O " ring, shaft pliers J-5403. seal and seal seat should be dipped in clean 525 Viscosity 7.
Page 218 1-6 AIR CONDITIONING J-25031-1 LOCKING WASHER SCREW Fig. 11 — Installing R otor an d B earing Puller G uide Fig. 1 3 —Clutch Coil an d H ousing Assem bly tighten puller screw against puller guide to remove Clutch Rotor Bearing R eplacem ent clutch rotor and assembly parts (Fig.
Page 219 AIR C O N DITIO N IN G BEARING STAKE LOCATIONS Fig. 14—B earing S ta k e Locations ROTOR BEARING Fig. 16— In s tallin g Clutch R otor B earing use new lockwashers. Do not torque mounting screws to final torque limits until pulley rim is checked to be rotating "in line".
Page 220 1-8 AIR CONDITIONING FRO NT HEAD AND M A IN BEARING ASSEMBLY Removal 1. Remove clutch rotor and bearing assembly but do not loosen or remove pulley rim mounting screws and remove clutch rotor, coil and pulley rim assembly as a total assembly. 2.
Page 221 AIR CO N D ITIO N IN G O IL H O LE TO Fig. 19— In s tallin g Front Head Fig. 2 0 — R eplacing T hrust an d B elleville W ashers in relation to compressor and that the three protrusions on rear of clutch coil align with the locator holes in front head.
Page 222 1-10 AIR CONDITIONING SHELL RETAINING STRAP Fig. 2 2 — In s tallin g M a in B earing COMPRESSOR SHELL, SHELL TO CYLINDER 'O 'R IN G AND VALVE PLATE REPLACEM ENT Fig. 2 3 —Releasing R e ta in in g S trap The clutch plate and hub assembly, the clutch rotor and bearing assembly, the clutch coil and pulley rim must be removed before compressor shell can be removed or...
Page 223 AIR CO N D ITIO N IN G 1-11 Dip remaining cylinder to shell "O " ring in oil and install it in front "O" ring groove of cylinder. Place compressor shell on cylinder and rotate retaining strap to its original location (Fig. 24). Attach shell installing fixture J-25008-2 to the holding fixture J-25008-1, using the long bolts and plate washers of tool set.
Page 224 1-12 AIR CONDITIONING drain the oil from compressor as in Step 1 and OIL CHARGE determine the amount of oil drained from the The radial four cylinder compressor is charged with 5.5- original compressor. 6.5 ounces of 525 viscosity oil. During normal operation 4.
Page 225 AIR C O N D ITIO N IN G 1-13 SPECIAL TOOLS 1. J -2 5 0 3 0 C lu tc h H u b H o ld in g T o ol 2 . J -2 5 0 2 9 R o to r B e a r in g R em over a n d R o to r Assy.
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Page 227 DANA 10 1 / 2 RING GEAR DIFFERENTIAL (E xcept Crew Salisbu r y /5 7 0 0 # Chevrolet 1 0 -1/2” The differentia! shown on page 4-55 of the 1974 Cab) Overhaul Manual has been modified for 1975,...
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Page 229 SECTION 5 BRAKES The 1975 brake boosters are essentially the same as those described in the 1974 Overhaul Manual, with the following exceptions: DELCO SINGLE DIAPHRAGM BOOSTER POWER PISTO N G R O U P ASSEMBLY GAUG ING The assembly procedure is the same as outlined in the All 1975 master cylinders incorporate shallow socket 1974 Overhaul Manual;...
Page 230 BRAKES BENDIX HYDRAULIC BRAKE BOOSTER (HYDRO-BOOST) INDEX Disassembly..................5-2 Cleaning and Inspection............... 5-3 Assembly.................... 5-4 OVERHAUL OPERATIONS The Bendix Hydraulic Brake Booster utilizes the bracket even though it is not necessary to remove the bracket for overhaul of the internal assembly. hydraulic pressure supplied by the power steering pump to provide power assist for brake applications (figs.
Page 231 BRAKES 26 25 24 22 21 W < o ^ | ( s p r = j ) { | 17 16 15 V4 13 12 11 Pedal Push Rod Plunger Seat O utpu t Push Rod Pedal Rod Retainer "...
Page 232 5-4 BRAKES corrosion, nicks, scoring or excessive wear. If the piston is damaged, the input rod and piston assembly should be replaced. 5. Inspect the piston bore in the booster housing for corrosion, nicks, scoring or other damage. If the bore is damaged, the entire booster must be replaced as an assembly.
Page 233 BRAKES INPUT RO D A N D « P IS TO N O p e n End o f Tool) Fig. 8 -ln s ta llin g In p u t Rod Seals Fig. 10- In stalling M o u n tin g B rack et N u t (T yp ica l) 8.
Page 234 5-6 BRAKES 16. Assemble a NEW boot (if used) on the pedal rod. NOTE: When the grommet is fully seated, the Then assemble a NEW grommet in the groove near pedal rod will rotate freely with no binding. the end of the pedal rod. 18.
Page 235 SECTION 6 ENGINE NOTE: Except for the following changes, all information listed in Section 6 of the 1974 Overhaul Manual is applicable to 1975 light duty trucks. Refer to 1974 Overhaul Manual for any procedure not contained herein. REPAIR PROCEDURES REPAIRS C A M SH A FT Piston Selection...
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Page 237 SECTION 6M CARBURETOR C O N TE N TS OF THIS SECTION Introduction..................6M-1 Rochester 1MV................6M-1 Rochester 2G C................6M-5 Rochester 4M V ............See Introduction Rochester M 4M C/M 4M CA............6M-11 Special Tools................... 6M-21 INTRODUCTION A carburetor is designed to meet the particular operations, when not part of a general overhaul, should requirements of the engine, transmission and vehicle and be performed (if practical) with the carburetor on the...
Page 238 6M -2 CARBURETOR PUMP LEVER PRESSURE RELIEF VALVE DISC PRIMARY V A C U U M BREAK D IA P H R A G M FUEL PUMP A N D FILTER METER IN G ROD A C T U A T IN G LEVER C H O K E LEVER A U XILIA R Y V A C U U M BREAK D IA P H R A G M...
Page 239 CARBURETOR 6M -3 actuator lever from end of throttle shaft by No further disassembly of the float bowl is required. removing lever attaching screw (Fig. 4). 5. Hold down on power piston while removing lever. Throttle Body (Fig. 6) Power piston spring and metering rod assembly may now be removed from float bowl (Fig.
Page 240 6 M -4 CARBURETOR 5. Inspect holes in levers for excessive wear or out of carburetor bore. Tang on upper end of link retains link to pump shaft. (Fig. 4). round condition. If levers are worn they should be replaced. 15.
Page 241 CARBURETOR 6M -5 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. © Air Horn BENDING TOOL 1. Install choke shaft assembly and choke valve into HO LD POWER ©...
Page 242 6M -6 CARBURETOR lockwashers, then lift air horn from float bowl (Fig. 3C). AIR HORN 8. Place air horn on flat surface. Remove float hinge ACCELERATO R pin and lift float from air horn. Float needle, and PUMP ROD FUEL INLET pull clip (if used), may now be removed from float NUT, arm (Fig.
Page 243 .... i l l....— — ■ — CARBURETOR 6M-7 plunger stem. This should not be done unless pump assembly replacement is necessary, such as during overhaul. The service pump assembly uses a grooved pump plunger stem and retaining clip. After removing the inner pump lever and pump assembly, remove the outer pump lever and shaft P L A S T I C M A I N...
Page 244 6M -8 CARBURETOR correctly in relation to the idle discharge orifices. CLEANING AND IN S P E C TIO N Dirt, gum, water or carbon contamination in or on exterior moving parts of the carburetor are often responsible for unsatisfactory performance. For this reason, efficient carburetion depends upon careful cleaning and inspection while servicing.
Page 245 CARBURETOR 6M -9 wells located beneath the venturi cluster and make ASSEMBLY sure they are seated in recesses provided (Fig. 6C). Then install venturi cluster and gasket, tighten T h ro ttle Body 1. Install idle speed screw and spring assembly in three screws evenly and securely.
Page 246 6M -10 CARBURETOR ( 5 ) v i s u a l l y c h e c k FOR FLOAT A L IG N M E N T Fig. IO C — Float Level A d ju s tm en t assembly rotating rod until squirt in end of rod aligns with slot in lever.
Page 247 CARBURETOR 6M-11 M4MC/M4MCA QUADRAJET CARBURETOR G eneral................6M-11 Assembly................6M-16 Disassembly..............6M-H Special Tools..............6M-21 Cleaning and Inspection..........6M-16 3. Remove vacuum hose from front vacuum break GENERAL unit. Before performing any service on the carburetor, it is 4. Remove secondary metering rods by removing the essential that the carburetor be placed on a holding small screw in the top of the metering rod hanger.
Page 248 6M -12 CARBURETOR Fig. 5 M Q —R em oving A ir H orn Screws Fig. 3 M Q —Rem oving Secondary M e te rin g Rods PUMP LEVER Fig. 6 M Q — R em oving A ir H orn Fig.
Page 249 CARBURETOR 6M -13 VACUUM BREAK SCREW (2) : J l T £ R i Fig. 9 M Q —R em oving Power Piston and M e te rin g Rods Fig. 7 M Q —Rem oving Front Vacuum B reak Remove the power piston spring from the well.
Page 250 6 M -1 4 CARBURETOR plates. These jets are fixed and, if damaged, float FLOAT bowl replacement is required. 10. Remove pump discharge check ball retainer and check ball. 11. Remove hose from rear vacuum break control assembly. Remove two screws from rear vacuum break bracket and rotate the assembly to remove vacuum break rod from slot in plunger head (Fig.
Page 251 CARBURETOR 6M -15 12. Remove vacuum break rod by holding down on fast idle cam (hot idle position); move end of vacuum break rod away from float bowl; then disengage rod from hole in intermediate choke lever. Choke 1. Remove three attaching screws and retainers from choke cover and coil assembly.
Page 252 6 M -16 CARBURETOR CLEANING AND IN SP E C TIO N 1. Thoroughly clean carburetor castings and metal parts in an approved carburetor cleaner, such as Carbon X(X-55) or its equivalent. The idle stop solenoid, throttle stop C A U TIO N : vacuum unit, rubber parts, plastic parts, pump plungers, filler spools or aneroid, and choke vacuum breaks should not be immersed in...
Page 253 CARBURETOR 6M -17 Choke Float Bowl 1. Install new cup seal into plastic insert on side of 1. Holding down on fast idle cam (hot idle position), float bowl for intermediate choke shaft. Lip on cup install end of vacuum break rod in hole in seal faces outward.
Page 255 CARBURETOR 6M -19 e. Visually check float alignment after adjustment. Air Horn to Bowl Installation 1. Holding down on air horn gasket at pump plunger 11. Install plastic filler block over float needle, pressing location, carefully lower air horn assembly onto downward until properly seated.
Page 256 6 M -20 CARBURETOR 7. After the vacuum break, fast idle cam, and inside lever pick-up arm. At this point, the index cover thermostatic coil lever are adjusted, the thermo should be adjusted as shown on adjustment chart. static coil and cover assembly and gasket should be Install three choke cover retainers and screws and installed and the cover assembly rotated until the tighten securely.
Page 257 CARBURETOR 6M-21 SPECIAL TOOLS J-22973 THER-MAC THERMOMETOR J-8328 CARBURETOR HOLDING TOOL J-9789-01 UNIVERSAL CARBURETOR (Set of 4) GAUGE SET J-25322 PUMP LEVER PIN DRIVE PUNCH J-23417 CHOKE LEVER J-5197 BENDING TOOL INSTALLING TOOL Fig. 1ST— Special Tools TRUCK SUPP ■ OVERHAUL www.PlandeGraissage.Org...
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Page 259 SECTION 6Y ENGINE ELECTRICAL NOTE: Except for the following changes, all information listed in Section 6Y of the 1974 Light Duty Truck Overhaul Manual is applicable to 1975 light duty trucks. Refer to 1974 Passenger Cars and Light Duty Truck Overhaul Manual for any overhaul procedure not contained herein.
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Page 261 SECTION 7A AUTOMATIC TRANSMISSION CO N TE N TS OF THIS SECTION Turbo Hydra-Matic 350 Transmission........7A-1 Turbo Hydra-Matic 375/400/475 Transmission....7A-2 TURBO HYDRA-MATIC 350 TRANSMISSION INDEX Disassembly..... 7A-1 Automatic Clutch Chart 7A-2 Inspection of Converter 7A-1 Converter End Clearance Check 7A-1 2.
Page 262 7A-2 AUTOMATIC TRANSM ISSIO N CLUTCH ASSEMBLIES FOR THM 3 5 0 CUSHION DRIVE DRIVEN CLUTCH SPRING PLATE PLATES FORWARD 250 L-6, 262 V-8 350 V-8, 400 V-8 TAXI AND TRUCK INTERMEDIATE 250 L-6, 262 V-8 350 V-8, 400 V-8 TAXI AND TRUCK DIRECT NONE...
Page 263 AUTOMATIC TRANSM ISSIO N 7A-3 375/400/475 TRANSMISSION TURBO HYDRA-MATIC INDEX Inspection of Front and Rear Bands, Support Removal of Rear Servo, Valve Body Spacer, 7A-3 to Case Spacer........... 7A-9 Gasket, and Front Servo........Inspection of Case Extension (Except CL Model) 7A-10 Removal of Oil Pump and Internal Case 7A-4 Components .............
Page 264 7A-4 AUTOMATIC TRANSM ISSION prevents the spacer plate and gasket and check balls from dropping down. 5. Remove detent solenoid attaching screws, detent TORQUE solenoid and gasket. WRENCH 6. Withdraw electrical connector and "O" ring seal. 7. Remove control valve assembly spacer plate and gasket.
Page 265 AUTOMATIC TR AN SM ISSIO N 7A-5 puller on output shaft, and remove speedometer CONTROL VALVE, DISASSEMBLY, drive gear (fig. 4B). IN SPECTIO N AND ASSEMBLY (Fig. 6B ) 2. Install new steel speedometer drive gear and drive to location (5-43/64" below end of output shaft for all models except CA, CB and CR) (11-15/64"...
Page 266 7A-6 AUTOMATIC TRANSM ISSIO N « 1 * ft jji^ r r r 10 11 * * • — — U U - g i n Ijuyy^! X ir n n r m m i x s z : wmm® 0 j | 22 23 f it ! as=Q ®...
Page 267 AUTOMATIC TRAN SM ISSIO N 7A-7 Fig. 9 B — In s tallin g D e te n t R egulator Valve an d D e te n t Valve 8. In lower right hand bore, install 3-2 valve. Fig. 7B — Installing C om pressor Tool to Front A ccum ulator Piston 9.
Page 268 7A-8 AUTOMATIC TRANSM ISSIO N grooved composition- faced, four (4) thick b. (Models CD, CF, CJ, CM, CP, CR and CT) Remove five (5) composition-faced and five (5) (.0915") flat steel and one ( 1) waved steel clutch flat steel clutch plates from the direct clutch plates from forward clutch housing.
Page 269 AUTOM ATIC TRANSM ISSIO N 7A-9 7. Install four (4) oil seal rings on the center support. NOTE: If Teflon rings are being re-used, make sure slit ends are assembled in same relation as cut. (Fig. 1 IB). C H EC K BALL IN SPEC TIO N OF REACTIO N CARRIER, ROLLER CLUTCH, AND O U T P U T CARRIER...
Page 270 7A-10 AUTOMATIC TRANSM ISSIO N R E AC TIO N SPACER CARRIER R IN G REAR OIL BALL BEARINGS SEAL SNAP BEARING RING SPACER CASE EXTENSION Fig. 12B — In specting Spacer R ing Fig. 13B — M odel CL C ase Extension oil seal, and install oil seal into case extension IN SPECTIO N OF CASE EXTENSIO N using tool (J-24057).
Page 271 AUTOM ATIC TR ANSM ISSIO N 7A-11 remove the nameplate from the old case and re install it on the new case, using the truss head nameplate attaching screw that is serviced with the case. ASSEMBLY OF REAR U N IT The procedure for assembly remains the same with the following addition: Assembly procedure, step number 11, should read:...
Page 272 7A-12 AUTOMATIC TRANSM ISSION 3. Install vacuum modulator into case. IN STA LLATIO N OF CHECK BALLS, NOTE: Models CA, CB and CK use a modulator CO NTRO L VALVE SPACER PLATE AND that is different than the modulator used on the GASKET, DETENT SOLENOID, other models.
Page 273 SECTION 7M CLUTCH AND MANUAL TRANSMISSION FOUR-SPEED MUNCIE TRANSMISSION (CH 465) INDEX Transmission Assembly..............7M-1 M ainshaft Assembly..............7M-2 2 Place fork detent ball springs and balls in position ASSEMBLY (Fig. IX ) in holes in cover. 1. In reassembling the transmission cover, care must 3.
Page 274 7M -2 TR AN SM ISSIO N 4. Hold 3rd and 4th fork in position and push shaft M A IN S H A FT ASSEMBLY through yoke, but not through front support bore. Disassembly (Fig. 3 X ) 5. Place two (2) interlock balls in cross-bore in front support boss between reverse and 3rd and 4th 1.
Page 275 T R AN SM ISSIO N 7M -3 4th S peed B lo c ke r 3 rd Speed B lo cker 2nd Speed B lo cker 1 st Speed Gear Ring Ring Ring Reverse Driven Gear Snap Ring 1 1. 3 rd -4 th Speed 2nd Speed Gear 1 st Gear B ushing...
Page 276 7M -4 TRAN SM ISSIO N Fig. 4X— Disassembly of Mainshaft NEW PROCESS TRANSFER CASE MODEL 203 INDEX Disassembly of transfer case............. 7M-4 Rear Output Shaft Housing (Rear) Assembly....7M-8 Rear Output Shaft Housing (Front) Assembly....7M-9 Assembly of Transfer Case............7M-9 4.
Page 277 TR AN SM ISSIO N 7M -5 4 4 . M agnet O il Pum p 1. A d ap te r S peedom eter D rive Gear 4 5 . D rive Chain In p u t D rive Gear P ilo t Brgs. 4 6 .
Page 278 7M -6 TRAN SM ISSIO N Fig. 2F-1— Transfer Case Exploded View www.PlandeGraissage.Org TRUCK SUPP ■ OVERHAUL...
Page 279 TR AN SM ISSIO N 7M -7 <3b 90 91 92 1. A d a p te r 48. T h ru s t W asher 2. In p u t G ear B e a rin g d e ta in e r 4 9 .
Page 280 7M -8 TR AN SM ISSIO N 16. Disengage front output shaft from chain and . remove shaft from transfer case. IN P U T G E A R 17. Remove bolts attaching intermediate chain housing to range box. Lift or using a chain hoist, remove F R O N T O U T P U T intermediate housing from range box.
Page 281 TR AN SM ISSIO N 7M -9 REAR O U TP U T SHAFT H O U S IN G (FR O N T) ASSEMBLY (Fig. 2F-2) Disassembly 1. Remove "O " ring from rear output shaft housing (front) and discard. 2.
Page 282 7M -10 TRANSM ISSIO N washer and retaining nut. Tap dust shield back in 19. Install flange, washer, and retaining nut. Leave nut place after installing bolts in flange. loose (approximately .060 inch) until shim require ments are determined. 13. Install front output shaft rear bearing retainer, 20.
Page 283 SECTION 9 STEERING OVERHAUL OPERATIONS Manual, Section 9, with the exception of the power All service overhaul procedures for 1975 Light Duty Trucks are identical to the procedures outlined in the steering pump pulley, removal and installation. 1974 Passenger Car and Light Duty Truck Overhaul 20.
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Page 285 SPECIFICATIONS 1 SPECIFICATIONS HEATING AND AIR CO N DITIO N IN G SECTION 1A H E A T E R Amps. Compressor Clutch Coil Volts (Cold) (Cold) Ohms (at 80° F ) ............3.70 Amps, (at 8 0 ° F )........3.33 @ 12 volts Blower Motor C-K Models.....
Page 286 SPECIFICATIONS 2 BODY SECTION IB C AND K MODELS F R O N T E N D E N D G A T E (0 6 ) Windshield Wiper Linkage to Plenum....... 25 in. lb. Hinges-Hinge to B o dy..........35 ft. lb. Sunshade S upport............
Page 287 SPECIFICATIONS 3 BODY MOUNTING (C-K MODELS)-FT. LBS. Model (03) — — (06) (14>(16) (63) G MODELS M I R R O R S A N D S U N S H A D E S L I D I N G S I D E D O O R Remote Control (front latch) to D o o r......90 in.
Page 288 SPECIFICATIONS 4 FRONT SUSPENSION SECTION 3 W H E E L A L I G N M E N T S P E C I F I C A T I O N S CASTER* DIMEN SION “A ’ IN INC HES* MODELS 2 1/2"...
Page 289 SPECIFICATIONS 5 FRONT SUSPENSION BO LT TORQUE (F t. Lbs.) $ G-30 K-AII G-10-20 CP-10 CP-20-30 — Lower Control Arm Shaft U-Bolt — Upper Control Arm Shaft Nuts — Control Arm Rubber Bushings w/Spacer 190 w/Spacer 160 Upper Control Arm Bushing Steel No Spacer 95 No Spacer 115 Used...
Page 290 * With wheel rotating. Lubricant Capacity Ring Gear Size 4 .2 Pints 8 - 1 /2 ” UNIVERSAL JOINT ATTACHMENT Chevrolet 10-1/2” 5.4 Pints TORQUE SPECIFICATIONS Dana 10-1/2” 7.2 Pints ..
Page 291 SPECIFICATIONS? TORQUE SPECIFICATIONS (FT. LBS.) (CONT’D.) G10 120 Spring-to-Axle “U” Bolt Nuts G20 120 G30 150 Leaf Spring —Front Bushing Bolt (G316. . .90) —Rear Shackle Bolt (G 3i6. . .90) Shock Absorber —Upper Attachment P10 25 P20 140 P30 50 —Lower Attachment Propeller Shaft 12-17...
Page 292 SPECIFICATIONS 8 BRAKES SECTION 5 TORQUE SPECIFICATIONS Master Cylinder - to Dash or Booster 25 ft. lbs. Booster to Dash or Frame 25 ft. lbs. Combination Valve - Mounting Bolts 150 in. lbs. - Bracket to Frame 25 ft. lbs. 25 ft.
Page 293 SPECIFICATIONS 9 ENGINE SECTION 6 GENERAL DATA: In Line Type Displacement (cu. in.) 3 7/8 4 1/4 Bore 3.53 4.12 3.48 Stroke 8.25:1 8.5:1 8.25:1 Compression Ratio 0 : 1 1-5-3-6-2-4 1-8-4-3-6-5- 7-2 Firing Order CYLINDER BORE: 4.2495 - 4.2525 3.8745 - 3.8775 3.9995 - 4.0025 Diameter...
Page 294 SPECIFICATIONS 10 CRANKSHAFT: #l-2-3-4 2.7485 -2.7494 2.4484 - 2.4493 #2-3-4 Diameter 2.2983 - 2.2993 2.7481 - 2.7490 2.4479 - 2.4488 Main 2.7478 - 2.7488 Journal Production .0002 (Max.) Taper Service .001 (Max.) Production .0002 (Max.) Out of Round Service .001 (Max.) .0008 - .0020 #l-2-3-4 .0003...
Page 295 SPECIFICATIONS 11 TUNE-UP CHART ENGINE Type In Line Displacement 130 psi 150 psi COMPRESSION © AC-R44TX AC-R44TX SPARK Make & AC-R46TX PLUG Number .060 DISTRIBUTOR Timing © SEE IGNITION SPECIFICATIONS 50 lb. Min 75 + 5 lbs. (Used)125±5 lbs.(New)Using Strand Tension Gauge Fan P/S and Air Pump DRIVE BELT...
Page 296 ECIFICATIONS 12 ENGINE TORQUES In Line Small V Mark IV V Usage Size 262 & 350 1/4-20 Camshaft Thrust Plate 80 lb. in. Crankcase Front Cover 80 lb. in. Flywheel Housing Cover 80 lb. in. Oil Filler Bypass Valve 80 lb. in. Oil Pan (To Crankcase) 80 lb.
Page 297 SPECIFICATIONS C A R B U R E T O R SEC TIO N 6M ID ENTIFICATIO N V E H IC LE ENG INE C A R B U R E T O R F E D E R A L C A L IF O R N IA B B L .
Page 298 SPECIFICATIONS C A R B U R E TO R A DJU STM EN TS IMV R o c h e s te r C a rb u re to r N UM BER C ho ke Rod P rim a ry A u x ilia ry (A) A u to m a tic T ra n s .
Page 299 SPECIFICATIONS C A R B U R E T O R A D J U S T M E N T S - Continued 4 M V R o c h e s te r C a rb u re to r C h oke Rod N U M B E R F lo a t...
Page 300 SPECIFICATIONS V E H IC L E E M I S S I O N C O N T R O L I N F O R M A T I O N LIGHT DUTY EMISSION VEHICLES GM 12F13 2 5 0 CU . IN . - FEDERAL/CALIFORNIA TRANSMISSION Autom atic Manual...
Page 301 SPECIFICATIONS 17 VE H IC LE E M I S S I O N C O N T R O L I N F O R M A T I O N - C O N T I N U E D HEAVY DUTY EMISSION VEHICLES - FEDERAL Spark...
Page 302 SPECIFICATION 18 ENGINE ELECTRICAL SECTION 6Y BATTERY Model No. Application Cold Crank Cranking Power 25 Amp Reserve Rate @0° F. (Watts) Capacity (Minutes) I9 8 0 l 99 (Y 8 7 P ) 250 L -6 2500 1980200 (R 8 9 P ) 292 L - 6 .
Page 303 SPECIFICATIONS 19 STARTING MOTOR Free Speed Battery Model No. Application Spec. No. Size Volts Amperes 1108744 250 L-6 (LD4) 3573 2300 Watts 50-80* 5500-10500 (C & K10) 1108778** 1108746 250 K -6 (LD4) 50-80* (G-Van) 3573 2300 Watts 5500-10500 1108779** 1108747 50-80* 3500-6000...
Page 304 SPECIFICATION 20 D IS T R IB U T O R Application Emiss Engine Centrifugal Vacuum Model No. Initial Spark Class Usage Advance Advance Timing Plugs 0 ° a 1 1 0 0 L -6 250 (LD4) L. D . Federal 0 °...
Page 305 SPECIFICATIONS 21 CLUTCH AND MANUAL TRANSMISSION SECTION 7M THREE SPEED SAGINAW DANA TRANSFER CASE MODEL 20 Clutch Gear Retainer to Case B olts....15 ft. lbs. Shift Rail Set Screws ........15 ft. lbs. Side Cover to Case Bolts ........ 15 ft.
Page 306 SPECIFICATIONS 22 AUTOMATIC TRANSMISSIONS SECTION 7A NEW PROCESS TRANSFER CASE MODEL 205 TURBO HYDRA-MATIC 350 Idler Shaft Lock N u t......... 200 ft. lbs. Idler Shaft Cover B olts........18 ft. lbs. Pump Cover to Pump B ody....... ft. lbs. Front Output Shaft Front Bearing Pump Assembly to Case.........
Page 307 SPECIFICATION 23 STEERING SECTION 9 TO R Q U E VALUES C 1 0 - 3 0 K 1 0 - 2 0 G 1 0 - 3 0 P 1 0 - 3 0 C o m p o n e n ts Tie Rod Ball Joint Nut 45 lbs.
Page 308 SPECIFICATION 24 T O R Q U E VALUES (Continued) C o m p o n en ts C 1 0 -3 0 K 1 0 -2 0 G 1 0 -3 0 P 1 0 -3 0 Lower Mast Jacket Bearing 30 lbs.
Page 309 SPECIFICATIONS 25 M A N U A L STEERING GEAR POWER STEERING GEAR Components All C, P, K and G Components G10-30 K10 - 20 P20 - 30 p103° Steering Gear Ball Drag 3 lbs. in. Max. Thrust Bearing 6 to 11 4 to 6 9 to 12 1/2 to 2 lbs.
Page 310 SPECIFICATIONS 26 W HEELS AND TIRES SE C TIO N 10 W HEELS Wheel Nut Torque - 10-30 Series SERIES DESCRIPTION TORQUE SERIES DESCRIPTION TORQUE K10, 15 7 /1 6 " Bolts (6) 70- 90 Ft. Lbs. G 1 0 ,15 7 /1 6 ”...
Page 311 SPECIFICATIONS 27 BODY AND CHASSIS ELECTRICAL SECTION 12 LAMP BULB DATA FUSES—CIRCUIT BREAKERS C-K-P TRUCK The w iring circuits are protected from short circuits by a com bination of fuses, circuit breakers, and fusible therm al links in the w iring itself. This Quantity Trade # Power...
Page 312 SPECIFICATIONS Section 12 (Continued) LAMP BULB DATA FUSES—CIRCUIT BREAKERS The wiring circuits are protected from short circuits by a combination of G TR U C K fuses, circuit breakers, and fusible thermal links in the wiring itself. This greatly reduces the hazard of electrically caused fires in the vehicles. The headlamp circuits are protected by a circuit breaker in the light switch.
Page 313 SPECIFICATIONS R A D I A T O R A N D GRILLE S E C T IO N 13 T O R Q U E S P E C IF IC A TIO N S Grille to Tie Bar 50 in.
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Chevrolet LIGHT DUTY TRUCK 1975 Service Manual

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