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TRUCK SERVICE MANUAL
TM 5-4210-230-14&P-1
FUEL SYSTEM
Priming the fuel system will be required whenever a
fuel filter is changed, lines are disconnected or when the
electric in-tank fuel pump is replaced.
1. Be sure fuel tank has sufficient fuel.
2. Turn switch key to "ON" position. (Do not start engine.)
3. Hold primer switch to "ON" position to energize electric fuel
pump.
4. Open vent valve on top of primary filter, close valve when
fuel flows out in solid stream.
5. Open vent valve on secondary filter; close valve when fuel
flows out in a solid stream.
6. Release primer switch.
PRESSURE CHECKING DIESEL ENGINE FUEL SYSTEM
(General)
The locations for making "on-engine" transfer pump
pressure checks or lift pump pressure checks are as follows:
1. Transfer Pump Pressure: This check is now made directly
on injection pump. Install an adapter fitting to priming inlet
at front of injection pump and connect compound test
gauge (SE2004-1) or test kit (SE-2239). Operate engine
under load and check transfer pressure (25-40 psi).
2. Lift Pump Pressure (now electric fuel pump): This check is
made at primary filter. Install adapter and compound test
gauge (SE-2004-1) or test kit (SE-2239) to priming vent on
primary filter. Operate engine under load and check
pressure (3 to 5 psi).
SERVICE FUEL PUMP
Screen Filter Type
Disassembly
The disassembly of mechanical pumps having the
screen filter, Fig. 4, can be accomplished in the following
manner:
1. Remove the cover bolt, cover and cover gasket. Also
remove the screen disc filter.
2. Match-mark the valve housing and pump body to assure
correct re-assembly of parts.
3. Remove the screws which hold the valve housing on the
pump body. Separate the housing from the body.
4. Remove the fuel valve retainer screws and retainer and lift
the inlet and outlet valves and gaskets out of the valve
housing.
5. Unhook the diaphragm from the diaphragm lever and pull
the diaphragm and pull rod assembly straight out to
prevent damage to the oil seal. Remove the diaphragm
spring.
6. Remove the oil seal retainer and oil seal from the pump.
7. If necessary to replace the cam lever, remove the pin
retainers from the end of the rocker arm pin. Drive out
the pin and withdraw the cam lever spring and diaphragm
lever from the pump body.
Inspection
If a fuel pump is overhauled, the diaphragm gaskets,
valves, cam lever, spring and diaphragm lever should always
be replaced whether these old parts appear serviceable or not.
Fuel pump repair kits containing these parts are available. All
other parts should be inspected as follows:
1. Inspect the pump body and valve housing for cracks and
breakage.
2. Check the pump body, valve housing and cover against a
flat surface for warpage.
3. Examine the pump body and valve housing for stripped or
crossed threads.
4. Replace screen.
5. Check the cam lever for wear at the camshaft pad and also
for wear at the point contacted by the diaphragm lever.
6. Check the springs for corrosion, fracture or weakness.
Assembly
All fuel pumps having the screen filter will have an
assembly procedure similar to the following. Refer to Fig. 4
for numbers in parentheses.
1. If the cam lever (21) was removed, place seal (16), seal
retainer (15) and spring (14) in pump body (17) and
install pull rod of diaphragm assembly (13) through
spring, retainer and seal. Assemble diaphragm lever (22)
with cam lever (24) and insert hooked end of lever
through opening in pump body (17) and engage with
diaphragm pull rod. Make sure lever spring (19) is also in
place. Obtain a piece of welding rod or
CTS-2050-F
Page 5
PRINTED IN UNITED STATES OF AMERICA
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