GMC 4000 Series Service Manual page 475

Sec. 8A
Page 464
FUEL TANK A N D EXHAUST
Figure 8 — Gasoline Tank Sending Unit
and fuel line(s). To remove the protector top, a
bolt at each side must be removed. The lower por­
tion of the gauge protector is sandwiched between
two gaskets beneath the top of the fuel gauge and
can be removed only after removal of gauge unit
from fuel tank.
Tilt Cab Models
1. Turn ignition switch or engine control
switch to "OFF" position.
2. Disconnect electrical wire from terminal
on tank unit.
3. Disconnect fuel line(s) at tank unit.
4. Remove screw s or bolts attaching tank unit
flange to tank. Then lift tank unit out of tank.
5. Carefully install new gasket and tank unit
in tank and align flange bolt holes.
Figure 9 — Tank Unit Protector
G M C S E R V I C E M A N U A L
SLOTTED
DOWEL
t'
RETAINING
electrical wire to terminal on tank unit.
Conventional Cab Models
moval and installation of tank unit. Tool can be
made from a common spanner wrench as follows:
spanner arm (see Inset on figure 10). Each slot
should be parallel to spanner arm as shown. The
saw slots should measure approximately 1/8 inch
deep and 1/16 inch wide (width of two hack saw
blades). File a flat surface perpendicular to slot at
each end of slots. Grind end of spanner arms if ad­
ditional clearance is needed.
Replace tank unit as follows:
switch to "OFF" position.
on tank unit. Also disconnect tank unit ground wire
at the frame.
gage two of the four ring lugs, then turn retaining
ring counterclockwise to loosen ring. Lift tank unit
out of tank. Remove and inspect neoprene O-ring.
Replace O-ring if necessary.
tool (fig. 10) to turn retaining ring clockwise and
secure tank unit.
wire to terminal on tank unit. Secure ground wire
SPANNER
ARM
WIRE TERMINAL
LUGS
RING
FUEL TANK
I ST RA P
Figure 10— Removing Retainer Ring
6. Install screws holding flange to tank.
7. Connect fuel line(s) at tank unit. Connect
A special tool can be devised to facilitate re­
Saw one slot in each dowel at end of each
1. Turn ignition switch or engine control
2. Disconnect electrical wire from terminal
3. Disconnect fuel line(s) at tank unit.
4. Position tool as shown in figure 10 to en­
5. Carefully install new tank unit in tank. Use
6. Connect fuel line(s). Then connect electrical
SPANNER WRENCH
FUEL TANK