1981 Chevrolet Light Duty Truck 10 to 30 Service & Repair Manual

CHEVROLET

FOREWORD This manual includes procedures for diagnosis, maintenance and adjust- ments, minor service operations, and removal and installation for components of Chevrolet Light Duty Trucks. Procedures involving disassembly and assembly of major components for these vehicles are contained in the 1981 Chevrolet Passenger Car and Light Duty Truck Unit Repair (Overhaul) Manual. Wiring diagrams for 1981 trucks are contained in a separate Wiring Diagram Booklet. The Section Index on the contents page enables the user to quickly locate any desired section. At the beginning of each section containing more than one major subject is a Table of Contents, which gives the page number on which each major subject begins. An index is placed at the beginning of each major subject within the section. Summaries of Special Tools, when required, and specifications are found at end of major sections. When reference is made in this manual to a brand name, number, or specific took an equivalent product may be used in place of the recommended item. This manual should be kept in a handy place for ready reference. If pro- perly used, it will enable the technician to better serve the owners of Chev- rolet built vehicles. All information, illustrations and specifications contained in this literature are based on the latest product information available at the time of publi- cation approval. The right is reserved to make changes at any time without notice.

IMPORTANT SAFETY NOTICE Proper service and repair is important to the safe, reliable operation of all motor vehicles. The service procedures recommended by Chevrolet and described in this service 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 of 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 of 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.

1981 LIGHT DUTY TRUCK (SERIES 10-35) CHASSIS SERVICE MANUAL 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 fasteners 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. TABLE OF CONTENTS SECTION GENERAL INFORMATION General Information OA Maintenance and Lubrication OB HEATING AND AIR CONDITIONING Heating and Ventilation 1A Air Conditioning 1B FRAME AND BUMPERS Frame and Body Mounts 2A Bumpers 2B Sheet Metal 2C Body 2D STEERING, SUSPENSION, WHEELS AND TIRES Front Alignment 3A Steering Linkage 3B1 Manual Steering 3B2 Power Steering 3B3 Steering Column 3B4 Front Suspension 3C Rear Suspension 3D Wheel and Tires 3E AXLE Propeller Shaft and Universal Joint 4A Rear Axle 4B Front Wheel Drive 4C BRAKES 5 ENGINE Engine 6 In-Line 6 6A1 Small Block 6A4 Mark IV 6A5 5.7L(Z) 350 Diesel 6A6 Engine Cooling 6B Engine Fuel 6C Model 1ME 6C1 Model 2SE 6C2 Model M2ME 6C3 Model M4ME 6C4 Fuel System 6C5 Engine Electrical 6D Engine Emission Controls 6E Engine Exhaust 6F Engine Performance Specifications 6G TRANSMISSION Automatic 7A Manual 7B Clutch 7C Transfer Case 7E ELECTRICAL — BODY AND CHASSIS Lamps and Lighting 8A Electrical and Wiring 8B Instrument Panel and Gages 8C ACCESSORIES 9 METRIC AND FASTENER INFORMATION 10 © 1980 General Motors Corporation Printed in U.S.A.

GENERAL INFORMATION OA-1 SECTION OA GENERAL INFORMATION CONTENTS OF THIS SECTION General .................................................................................................................... 0-1 Vehicle Identification Num ber ......................................................................... 0-2 Service Parts Identification Sticker ................................................................. 0-3 Vehicle Loading .................................................................................................... 0-3 Engine Code Number ......................................................................................... 0-3 Unit and Serial Number Locations ................................................................. 0-3 GENERAL Information to identify the vehicle and vehicle components appears in this section. Detailed specifications on major units are given at the end of each respective section in this manual. VEHICLE IDENTIFICATION NUMBER (VIN) This is the legal identification of the vehicle. It appears on a plate which is attached to the left top of the instrument panel on CK and G truck and can be easily seen through the windshield from outside the vehicle (Fig. 0A-1). On P10-20- 30 models, the plate is attached to the front of the dash and toe panel to the left of steering column (Fig. 0A-2). The VIN also appears on the Vehicle Certificates of Title and Registration. and G) MFD. BY GENERAL MOTORS CORPORATION CAWR GAV,R REAR INFLATION DATA FOR TIRES FURNISHED WITH VEHICLE SHOWN ON VEHICLE CERTIFICATION LABEL Q WARRANTY VOIDED IF L0A0E0 IN EXCESS OF RATINGS Q SEE OWNERS MANUAL FOR OTHER LOADING AND INFLATION DATA EXAMPLE ONLY Fig. 0A-2--V.I.N. Rating Plate (P Model) LIGHT TRUCK SERVICE MANUAL

OA-2 GENERAL INFORMATION VEHICLE IDENTIFICATION NUMBER 1GCEC14 0 9BF123456 NATION OF ORIGIN 1 U.S.A. 2 CANADA MANUFACTURER G GENERAL MOTORS MAKE AND TYPE BUS (VAN) INCOMPLETE VEHICLE TRUCK MULTIPURPOSE PASS VEHICLE GVWR/BRAKE SYSTEM GVWR CODE (IN POUNDS) B 3001 4000 •c 4001 5000 D 5001 6000 E 6001 7000 F 7001 8000 ■G 8001 9000 H 9001 10000 J 10001 14000 K 14001 16000 BRAKE SYSTEM HYDRAULIC ONLY Includes El Camino Includes G Van Bus. TRUCK SERIES 1 112 TON 2 3/4 TON 3 1 TO N 8 112 TON (EL CAMINO) LINE AND CHASSIS TYPE CODE LINE MODELS CHASSIS TYPE C CONVENTIONAL CAB (Cl 4X2 K CONVENTIONAL CAB (K) 4X4 P FORWARD CONTROL CHASSIS (P) 4X2 G VAN. SPORT VAN & CUTAWAY VAN (G) 4X2 W EL CAMINO (APU) 4X2 PLANT SEQUENTIAL NUMBER MODEL YEAR B 1981 C 1982 D 1983 E 1984 F 1985 G 1986 H 1987 1 1988 K 1989 L 1090 M 1991 ASSEMBLY PLANT CODE ASSEMBLY PLANT CODE ASSEMBLY PLANT A GMAD - LAKEWOOD S GMAD - ST LOUIS B GMAD - BALTIMORE V GMT & C -- PONTIAC D GMAD - DORAVILLE ' Z GMAD- FREMONT * F CHEVROLET - FLINT 1 GM OF CANADA - OSHAWA J GMAD - JANESVILLE 3 CHEVROLET - DETROIT K GMAD - LEEDS ' 4 GM OF CANADA - SCARBOROUGH R GMAD - ARLINGTON ' 7 GMAD - LORDSTOWN • EL CAMINO PLANTS CHECK DIGlT] TRUCK BODY TYPE SEDAN PICKUP 1 HI CUBE/CUTAWAY VAN 2 FORWARD CONTROL 3 FOUR DOOR CAB 4 TWO DOOR CAB 5 VAN 6 SUBURBAN 7 MOTOR HOME 8 BLAZER STAKE/PLATFORM ENGINE TYPE AND MAKE TYPE MAKE (GM) CODE DISPLACEMENT LITRES (CU IN) ENGINE SOURCE MODELS RPO D 4.1 L L6 2BBL (250) CHEVROLET G LE3 F 5.0L V8 4BBL (305I CHEVROLET C-K-G LF3 G 5.0L V8 2BBL (305) CHEVROLET C-K-G LG9 H 5.0L V8 4BBL (305) CHEVROLET C-K-G LE9 L 5.7L V8 4BBL (350) CHEVROLET C-K-G LS9 M 5.7L V8 4BBL (350) CHEVROLET C-K-G-P LT9 P 5.7L V8 2BBL (350I CHEVROLET CK LF5 W 7.4L V8 4BBL (454) CHEVROLET C-K-P LE8 T 4.8L L6 1BBL (292) CHEVROLET C-K-P L25 Z 5.7L V8 DIESEL (350I OLDSMOBILE CK LF9 (FOR EL CAMINO ONLY) V I. N. TYPE MAKE (GM) CODE DISPLACEMENT LITRES (CU IN) ENGINE SOURCE MODEL RPO A 3.8L V6 2BBL (231) BUICK EL CAMINO LD5 H 5.0L V8 4BBL (305) CHEVROLET EL CAMINO LG4 J 4 4L V8 2BBL (267) CHEVROLET EL CAMINO L39 K 3.8L V6 2BBL (229) CHEVROLET EL CAMINO LC3 LIGHT TRUCK SERVICE MANUAL Fig. 0A-3--Vehicle Identification Number

GENERAL INFORMATION OA-3 SERVICE PARTS IDENTIFICATION STICKER The Service Parts 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. The plate lists the vehicle identification number, wheelbase, and all Production options or Special Equipment on the vehicle when it was shipped from the factory including paint information. ALWAYS REFER TO THIS INFORMATION WHEN ORDERING PARTS. VEHICLE LOADING Vehicle loading must be controlled so weights do not exceed the numbers shown on the Vehicle Identification Number and/or Rating Plate for the vehicle. A typical example of a truck in a loaded condition is shown in Figure OA-7. Note that the axle or GVW capabili - ties are not exceeded. ENGINE CODE NUMBER The engine code number indicates manufacturing plant, month and day of manufacture, and transmission type. A typical engine number would be F1210TTBB, which would breakdown thus: F - Manufacturing Plant (F-Flint, T-Tonawanda) 12 - Month of Manufacture (December) 10 - Day of Manufacture (tenth) T - Truck TBB - Transmission and engine type UNIT AND SERIAL NUMBER LOCATIONS For the convenience of service technicians and engi- neers when writing up certain business papers such as Warranty Reports, Product Information Reports, or report- ing product failures in any way, the location of the various unit numbers have been indicated. These unit numbers and their prefix or suffix are necessary on these papers for various reasons - such as accounting, follow-up on produc - tion, etc. The prefixes on certain units identify the plant in which the unit was manufactured and thereby permits proper follow-up of the plant involved to get corrections made when necessary. Always include the prefix in the number. Axles Chevrolet Built • On 10 Series, the Code is stamped on Top of Right Rear Axle Tube. • On 20-30 Series, the Code is stamped on Top of the Right Rear Axle Tube. Dana Built • On Front Axles, code is stamped on Top Rear of Left Axle Tube. • On Rear Axles, code is stamped on Rear Surface of Right Axle Tube. Transmissions (Fig. OA-6) • On 3-Speed Transmissions (except Tremec), the Unit Number is located on Lower Left Side of Case Just Below Cover. • On Tremec Transmissions, Unit Number is located on Upper Left Attachment Case (Top Side). • On Muncie 4-Speeds, Unit Number is located on Rear 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 Automatic 350 Transmission, Unit Number is Located on Right Rear Vertical Surface of Oil Pan. • On the Automatic 400 Transmission, Serial Number is Located on the Light Blue Plate on the Right Side of the Transmission. LOADED-MAXIMUM GVWR: 4900-LBS. FRONT GAWR: 2944 LBS. REAR GAWR: 2944 LBS. * Front Curb Front Cargo & Pass. Load 2219 lbs. 284 lbs. *Rear Curb Rear Cargo & Pass. Load 1003 lbs. 1394 lbs. 2503 lbs. 2397 lbs. TOTAL WEIGHT AT GROUND: 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 LIGHT TRUCK SERVICE MANUAL

OA-4 GENERAL INFORMATION PRIMARY V .I.N . LOCATION (M l5) 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 (MCI) OPTIONAL V.I.N. LOCATION (M20) V.I.N. LOCATION (OPTIONAL) (M40) V.I.N. LOCATION (OPTIONAL) (M40) VIEW V.I.N. LOCATION (M20) MANUAL AUTOMATIC Fig. 0A-6--Transmission V.I.N. Location Engines (Fig. 0A>7) • 6-Cylinder Engine Unit Number Located on Pad at Right Hand Side of Cylinder Block at Rear of Distributor. • 8-Cylinder Gasoline Engine Code is (305, 350, 400 CID) Located on Pad immediately forward of right hand cylinder head. • 8-Cylinder Gasoline Engine (454 CID) Code is located on a pad of the front top center of the engine block immediately forward of the inlet manifold. • 8-Cylinder Diesel Engine Code is on a label located on rear face of the left valve cover. Generators Generator Unit Serial Number is located on the Drive End Frame Below the Part Number. Batteries Battery Code Number is Located on Cell Cover Top of Battery. Starters Starter Serial Number and Production Date are Stamped on Outer Case, Toward Rear. LIGHT TRUCK SERVICE MANUAL

GENERAL INFORMATION OA-5 Fig. 0A-7-Engine V.I.N. Location DISTRIBUTOR PAD L6 ENGINE V8 ENGINE — DIESEL ENGINE V.I.N. (OPTIONAL) # ENGINE ENGINE ENGINE V.I.N. ENGINE V.I.N. (OPTIONAL) V.I.N. ENGINE CASE PAD LIGHT TRUCK SERVICE MANUAL

MAINTENANCE AND LUBRICATION OB-1 SECTION OB MAINTENANCE AND LUBRICATION CONTENTS Maintenance Schedule .................................................................................. OB-2 Lubrication and General Maintenance .................................................... 0B-5 Safety Maintenance ...................................................................................... OB-15 Emission Control Maintenance ............................................................. OB-16 Specifications .................................................................................................... 0B-18 Recommended Fluids and Lubricants ..................................................... OB-18 Fluid Capacities ............................................................................................. OB-19 LIGHT TRUCK SERVICE MANUAL

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1981 Chevrolet Light Duty Truck 10 to 30 Service & Repair Manual

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