FUEL T A NK S A N D EXHAUST
8-1
FUEL TANKS AND EXHAUST
Also refer to the "Emission Control Systems Booklet for required
maintenance and warranty information.
CONTENTS OF THIS SECTION
Description............................................................................. 8-1
Diagnosis (Exhaust and ECS System)......................... 8-34
Service Operations (Incl. Maintenance Item s)......... 8-2
Special Tools......................................................................... 8-35
DESCRIPTION
All cab model trucks have fuel tanks relocated and
mounted outside of the cab, outboard of the right frame
rail. The tank is constructed of two steel sections, seam
welded, together. Because of the outside location of the
base and optional auxiliary tank, a plastic shield is
released for all series and models for 1973. The shield is
clipped to the tank and is bolted to the bracket mounting
which is attached to the frame, protecting the full frontal
area of the tank. Also a steel "bathtub type" skid plate,
is bolted to frame and fuel tank bracket.
On 1 ton forward control models and cowl models, the
tank is mounted on the outside of the left frame side
rail. A strong mounting of two metal straps anchor these
tanks to mounting brackets which are bolted to the
frame side member.
On 1/2 and 3/4 ton conventional and 4-wheel drive
models, Suburban and Utility, the tank is located to the
rear of the axle and between the side rails and envelopes
the forward edge of the spare tire. These tanks are
supported by one or two steel straps which are held at
either end by a hook into the side rail. Metal to metal
contact between tank and brackets or straps is prevented
by the use of anti-squeak material.
Upper and lower filler necks vary as to size, length and
shape, depending on model requirements. These necks
are treated so that rust will not form and get into the
fuel system. Lower filler necks are first bolted or riveted
to the tank, except on cab models, and then sweat
soldered in place to eliminate any possibility of leakage
at this point.
The fuel pickup pipe is built integrally with the tank
gauge unit, located at the top of the tank. A large area,
SECTION 8
LIGHT DUTY TRUCK SERVICE MANUAL
fine-mesh screen is located on the bottom of the fuel
pickup pipe. This screen is designed to prevent the
entrance of dirt or water into the fuel system, and
operates with a self-cleaning action.
Frame mounted tanks consist of an upper and lower
half, each with a wide flange. The two tank sections are
seam welded at the flange around the entire tank to
assure leakproof construction. Exceptional stiffness is
secured by the combination of the welded flanges and
depressed ribs in both upper and lower tank sections.
EVAPORATION CONTROL SYSTEM (ECS)
The Evaporation Control System (ECS) is standard
equipment under federal regulations for all truck series
rated under 6,000 pounds maximum obtainable GVW
and all people carrying vehicles. Important changes have
been made to improve performance and increase
reliability. The most noteworthy being in the area of fuel
fill. Past versions used partial inner tanks as fuel fill
limiter devices. Current designs use filler necks extended
further into the fuel tank and a revised fill vent tube.
TANK FILLER NECK GAS C A P -1 0 SERIES
AND
TRUCKS CLASSED AS PEOPLE CARRIERS
The truck fuel tank filler cap has a pressure-vacuum
safety relief valve.
NOTE: The gas cap requires replacement,
only a cap identified on the inside of the cap
with "pressure-vacuum" should be used.
Failure to use the correct cap can result in a
serious malfunction of the system.
Summary of Contents for Light Duty Truck 1973
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Page 53: ...HEATER AND AIR CONDITIONING 1A 27 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 115: ...LIGHT DUTY TRUCK SERVICE M A N U A L HEATER AND AIR CONDITIONING 1A 89...
Page 123: ...BODY 1B 3 Fig 6 Typical 06 Van LIGHT DUTY TRUCK SERVICE MANUAL...
Page 149: ...BODY 1B 29 Fig 84 Body Mounting 06 Fig 85 Body Mounting 14 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 171: ...LIGHT DUTY TRUCK SERVICE M A N U A L Fig 2 Frame Horizontal Checking Typical FRAME 2 3...
Page 173: ...LIGHT DUTY TRUCK SERVICE M A N U A L Fig 4 10 30 Series Truck Frame FRAME 2 5...
Page 174: ...2 6 FRAME LIGHT DUTY TRUCK SERVICE MANUAL Fig 5 Underbody Reference Points G Van...
Page 185: ...FRONT SUSPENSION 3 11 Fig 16 Toe out on Turns LIGHT DUTY TRUCK SERVICE MANUAL...
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Page 351: ...ENGINE 6 15 Fig ID Sectional View of Eight Cylinder Engine LIGHT DUTY TRUCK SERVICE MANUAL...
Page 375: ...EN G IN E 6 39 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 376: ...6 4 0 ENGINE LIGHT DUTY TRUCK SERVICE MANUAL...
Page 377: ...ENG IN E 6 41 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 378: ...LIGHT DUTY TRUCK SERVICE MANUAL Fig 37L K Series Engine Front Mount 6 42 ENG INE...
Page 400: ...6 6 4 ENG INE LIGHT DUTY TRUCK SERVICE MANUAL...
Page 401: ...ENG IN E 6 65 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 402: ...6 6 6 ENGINE LIGHT DUTY TRUCK SERVICE MANUAL...
Page 403: ...E NG IN E 6 67 Fig 36V C Series Engine Mounts LIGHT DUTY TRUCK SERVICE MANUAL...
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Page 423: ...EN G IN E C OOLING 6K 13 Fig 16 Overheating Chart LIGHT DUTY TRUCK SERVICE MANUAL...
Page 424: ...6 K 1 4 ENG INE COOLING Fig 17 Coolant Loss Chart LIGHT DUTY TRUCK SERVICE MANUAL...
Page 456: ...6M 32 ENGINE FUEL Fig K15 Accelerator Controls G Van L 6 LIGHT DUTY TRUCK SERVICE MANUAL...
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Page 512: ...Fig 18e Vacuum Advance Diagram V8 Engine...
Page 516: ...6 T 2 4 E M IS S IO N CONTROL SYSTEMS LIGHT DUTY TRUCK SERVICE MANUAL...
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Page 593: ...CLUTCHES MANUAL TRANSMISSIONS 7M 3 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 598: ...7M 8 CLUTCHES MANUAL TRANSMISSIONS LIGHT DUTY TRUCK SERVICE MANUAL...
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Page 743: ...FUEL TANKS AND EXHAUST 8 13 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 744: ...8 14 FUEL TANKS AND EXHAUST LIGHT DUTY TRUCK SERVICE MANUAL...
Page 760: ...8 30 FUEL TANKS AND EXHAUST Fig 40 Exhaust Pipe P Models LIGHT DUTY TRUCK SERVICE MANUAL...
Page 761: ...FUEL TANKS AND EXHAUST 8 31 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 763: ...FUEL TANKS AND EXHAUST 8 33 LIGHT DUTY TRUCK SERVICE MANUAL...
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Page 832: ...LIGHT DUTY TRUCK SERVICE MANUAL Fig 106 Power Steering Pump Mounting Typical 9 66 STEERING...
Page 833: ...PUMP ASSEMBLY STEERING GEAR TYPICAL SMALL V8 TYPICAL LARGE V8 STEERING 9 67...
Page 861: ...STEERING 9 95 Fig 134 Power Steering Pump Leakage LIGHT DUTY TRUCK SERVICE MANUAL...
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Page 886: ...11 10 CHASSIS SHEET METAL LIGHT DUTY TRUCK SERVICE MANUAL...
Page 891: ...ELECTRICAL BODY AND CHASSIS 12 5 LIGHT DUTY TRUCK SERVICE MANUAL...
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