GMC 4000 Series Service Manual page 474

LATCH PLATE
UPSET FLARE PUNCH
DIE B L O C K \
TUBE '
STOP
PLATE
Figure 5 — Flaring Operation (First Flare)
5. Draw latch plate nuts down tight to prevent
tube from slipping. Draw nuts down alternately
beginning with nut on closed side to prevent dis­
tortion of plate.
6. Remove punch and ram. R everse punch and
place back in tool body. Install ram and tap lightly
until face of punch contacts face o f. die blocks to
complete first flare operation (fig. 5).
7. Remove ram and punch.
8. Insert finish flare and ram in tool body and
tap ram until a good seat is formed (fig. 6).
9. Blow tubing out with com pressed air.
FUEL LINE MAINTENANCE
The fuel lines should be inspected occasionally
for leaks, kinks, or dents. If evidence of dirt is
found in the carburetor, fuel pump, or fuel filter on
disassem bly, the lines should be disconnected and
blown out. Check the fuel strainer in the tank for
damage or om ission. A leaking fuel tank should be
repaired or replaced immediately. Crimped, kink­
ed, or leaking fuel lines should be replaced.
When installing fuel lines, tighten tubing nuts
only enough to prevent leakage and provide a s e ­
cure connection. Where possible, a back-up wrench
should be used to prevent twisting or excess stress
on tubing.
When replacing a flexible fuel line, be sure
hoses are properly located to prevent chafing
against frame members. Fuel line retainers should
be positioned properly on fuel lines to assure s e ­
cure support, yet not result in line constriction.
Cracked, corroded, or bent retainers should be
replaced.
NOTE: Refer to FUEL SYSTEM (SEC. 6M) of
this manual for information pertaining to mainten­
ance and replacement intervals for In-line and
frame mounted fuel filters.
FUEL LINE RETAINER CLIP (Fig. 7)
A periodic inspection should be made to be
sure lines are securely mounted. If fuel pipes and
retainer clips are removed, Tool (J-7777) should
be used to install new retainer clips (fig. 7). After
removal of the old clip from the frame, position the
new clip in the location of the old clip. Index the
''blind rivet" and p ress hard (hand pressure should
do) to expand rivet.
G M C S E R V I C E M A N U A L
RAM GUIDE
, RAM
TANK UNIT (Fig. 8)
tank gauge unit are one assembly. The sock-type
strainer, located on bottom of fuel pickup pipe, is
of plastic wrap construction with a heat sealed end.
The large area fuel strainer is of sufficiently fine
mesh to prevent entrance of contaminants into fuel
system and operates with a self-cleaning action.
Inspect condition of strainer if tank unit is removed
and replace or clean as required.
stat) which controls current through the dash gauge
according to position of float. The tank unit rheo­
stat may be checked with an ohmmeter. With float
on "EMPTY" position, ohmmeter connected across
rheostat should indicate .00 to 1.0 ohms resistance.
With float on "FULL" position, resistance should
measure about 90 ohms for conventional cab models
and 30 ohms for steel tilt models.
TANK UNIT REPLACEMENT
(fig. 9) to shield tank unit electrical connections
FUEL TANK AND EXHAUST
1ST O P E R A T IO N 2ND O P E R A T IO N
UPSET F L A R E
PUNCH
Figure 6 — Flaring Operation (First and Second Flare)
FUEL GAUGE SYSTEM
The fuel tank strainer, fuel pickup pipe, and
The tank unit houses a variable resistor (rheo­
NOTE: Tank may incorporate a protective top
Figure 7 — Installing Fuel Line Retainer
Sec. 8A
Page 463
FINISH F LA R E
PUNCH T-3951
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