Chevrolet 10 Series 1968, Service Manual

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SECTION 8
FUEL TANK AND EXHAUST
CONTENTS OF THIS SECTION
Page
Fuel T a n k ................................................................................ 8-1
Exhaust S y s te m ....................................................................... 8-7
FUEL TANK
INDEX
Page Page
General D e s c r ip t io n .............
Service O p e ra tio n s ................
Draining T a n k ...................
Gauge Unit or Fuel Strainer
Fuel Tank .............................
GENERAL DESCRIPTION
8-1 F ille r Neck Assem bly - Chevy V a n ................................ ... 8-4
8-1 Fuel Line S e r v i c e ............................................................. ... 8-4
8-1 Fram e Mounted - Fuel F i l t e r ............................................. 8-5
8-2 Fuel Line Retainer C l i p ................................................... ... 8-5
8-2 Special T o o l s .......................................................................... ... 8-8
All cab model trucks (except T ilt Cabs) have a 21 gal­
lon capacity (approx.) fuel tank mounted behind the seat
within the cab. The tank is constructed of two steel
sections, seam welded together. The filter neck extends
through the left side of the cab, at a convenient height
from the ground. Exceptional stiffness is secured by the
combination of the welded flanges and depressed ribs in
both the front and rear halves. The tank is bolted to the
rear of the cab and to the floor panel.
Frame mounted tanks are located on the right side of
the chassis and lay lengthwise outside the frame side rail
on Forward Control, 1-1/2, and 2 ton models.
On 1 ton models, the above information also applies
except that 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 the tank is located to the rear of the axle and be­
tween 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.
The Chevy Van Fuel Tank has a 24.5 gallon capacity
(approximate), with left hand side fill and is mounted be­
tween the frame rails behind the rear axle. The tank is
held in place by two metal straps attached individually to
the underbody at each end. The straps hinge at the fo r­
ward end and secure the tank at the rear with an adjust­
able bolt and nut assembly (fig.
6 ).
Fuel tank filler caps and neck assemblies conform to
the latest SAE Standards for fille r caps and related filler
neck cams. These units are interchangeable with 1967
models for service replacement.
Upper and lower fille r 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 riv­
eted to the tank, except on cab models, and then sweat
soldered in place to eliminate any possibility of leakage
at this point.
All tanks are equipped with a vented filler neck cap.
A ll 40 through 60 Series trucks incorporate a pressure
relief valve which reduces fire hazard by eliminating an
open vent to the atmosphere and preventing spillage in
case of overturn.
The fuel pickup pipe is built integrally with the tank
gauge unit, located at the top of the tank. A large area,
fine-mesh screen is located on the bottom of the fuel
pickup pipe. This screen is designed to prevent the en­
trance 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 and baffles which are
pressed into the tank halves. The two tank sections are
seam welded at the flange around the entire tank to as­
sure leakproof construction.
Exceptional stiffness is
secured by the combination of the welded flanges and de­
pressed ribs in both upper and lower tank sections. Baf­
fle plates are incorporated to provide additional stiffness
and to prevent the surging of gasoline within the tank.
SERVICE OPERATIONS
DRAINING FUEL TANK
If the fuel tank does not incorporate a drain plug, it
will be necessary to siphon fuel from the tank when
draining
is needed. The following procedure is
recommended:
1. Obtain approximately 10 feet of 3/8" I.D. hose and
cut a flap-type slit 18" from one end. Make this
cut in the direction of the shorter end of hose (See
figure
1 ).
2. Insert a small pipe nipple (slightly larger O.D. than
the hose I.D.) into the opposite end of hose.
3. Insert the nipple end of siphon hose into the fuel
tank filler neck with the natural curl of the hose
pointed down. Insert until the hose is heard to strike
the bottom of the tank.
CHEVROLET TRUCK SERVICE MANUAL