TM-5-3805-254-14-P-2
TRUCK, DUMP, 20 TON, 6X4, ON-OFF HIGHWAY 71,000 GVW, IHC MODEL F-5070 (CCE)
TECHNICAL MANUAL; OPERATOR’S, ORGANIZATIONAL, DIRECT SUPPORT, GENERAL SUPPORT AND DEPT MAINTENANCE MANUAL (INCLUDING REPAIR PARTS INFORMATION AND SUPPLEMENTAL MAINTENANCE INSTRUCTIONS)
JUNE 1980
TM-5-3805-254-14-P-2 - Page 504 of 894
TRUCK SERVICE MANUAL
FUEL SYSTEM
Capscrews And Washers
Capscrews used in connecting a part to aluminum
should have an engaging thread length two times the
diameter.
Observance of this rule will prevent stripping
threads with a capscrew that is too short or breaking a
part from using a capscrew that is too long.
Lockwashers must never be used next to aluminum.
Always use a flat washer between the lockwasher and
aluminum part.
FUEL PUMP FILTER SCREEN
Cummins engines are equipped with single or double
fuel screens, located in fuel pump housing.
Disassembly And Inspection
Two types of screens are used on PT Fuel Pumps.
1.
The standard automotive screen assembly mounts in
top of fuel pump housing.
Fig. 5-16.
a.
Remove upper retainer, the top retainer contains a
magnet to pick up any iron particles that may have
entered the fuel pump.
Some screens are one piece.
b.
The lower retainer and screen has hole In center to
permit fuel flow.
c.
Clean retainer in fuel oil and blow dry with
compressed air.
Visually inspect retainer and magnet for
damage or excessive wear.
d.
Proper cleaning of the filter screens can best be
accomplished by soaking In a carbon-dissolving agent,
followed by flushing in a sonic cleaner unit, or clean the
screen and retainer portion in fuel oil and dry with
compressed air.
e.
Visually Inspect screen for holes or imbedded metal
particles in mesh.
f.
Discard damaged or worn parts and replace with
new parts.
Fig. 5-16,
F5183.
Fuel filter screens
Filter Screen Optional Replacements
Two new fuel filter screens, both with a 40 micron mesh
rating, are available for use in the PT fuel pumps.
Filter
screen, Part No.
200004, is used to replace screen, Part
No. 146483, when additional protection is desired in
single screen type fuel pumps.
Use of the new screen also provides a good check on
the primary fuel filter to see If the filter is performing its
proper filtration functions.
Tests with a good primary
filter indicated the 200004 Screen should be cleaned at
50,000 mile or 1600 hour intervals.
However, when a
questionable primary filter was used, the screen cleaning
periods had to be moved up to much closer intervals to
prevent clogging.
FUEL PUMP HOUSING
The fuel pump housing is the largest part of the fuel
pump and contains the governor barrel, throttle shaft
The drive shaft bushing, throttle sleeve, governor barrel
and spring pack housing still remain in the fuel pump
main housing.
The drive shaft bushing and governor barrel can be
removed if damaged.
The throttle sleeve was honed to
size after assembly to the housing, and due to the close
tolerances must be returned to a Cummins Distributor for
repair or replacement.
Exchange housings are available
to reduce downtime to a minimum, as this is a
specialized repair and only performed by Factory Repair
Stations.
Drive Shaft Bushing
1.
Check drive shaft bushing for sign of seizure or
burrs.
2.
Check drive shaft bushing 1.D.
with inside
micrometers; If worn beyond 0.7525 Inch [19.11 mm]
replace bushing.
3.
Remove worn bushing using a gouge chisel or half
Inch pipe tap, After tapping bushing, screw a half inch
pipe cap on a close nipple and screw the half inch nipple
into the bushing.
Insert a punch through the rear of the
housing and drive out the bushing.
4.
Apply a thin coat of high pressure lubricant to a new
front drive shaft bushing; press bushing into housing
flush with housing bore using an arbor press.
5.
Line ream bushing to 0.7495 to 0.7505 inch [19.04 to
19.06 mm] with ST-490 Ream Fixture, and a well oiled
0.750 inch (3/4 inch [19.05 mm] ) reamer, Fig. 5-17.
Check bushing I.D.
499
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