TM 5-3810-300-24&P-3
Fuel Pump 2.2
A spring-loaded relief valve incorporated in the pump
2. Remove the three pump attaching bolt and seal
body normally remains in the closed position, operating
assemblies, using wrench J 4242, and withdraw the
only when pressure on the outlet side (to the fuel filter)
pump from the blower.
reaches approximately 65 psi (448 kPa).
3. Check the drive coupling fork and, if broken or worn,
replace it with a new coupling.
Operation
Disassemble Fuel Pump
In operation, fuel enters the pump on the suction side
and fills the space between the gear teeth which are
With the fuel pump removed from the engine and
exposed at that instant. The gear teeth then carry the
mounted in holding fixture J 1508-10 as shown in Fig. 4,
fuel oil to the discharge side of the pump and, as the
refer to Figs. I and 6 and disassemble the pump as
gear teeth mesh in the center of the pump, the fuel is
follows:
forced out into the outlet cavity.
Since this is a
continuous cycle and fuel is continually being forced into
1. Remove the eight cover bolts and withdraw the pump
the outlet cavity, the fuel flows from the outlet cavity into
cover from the pump body. Use care not to damage the
the fuel lines and through the engine fuel system under
finished faces of the pump body and cover.
pressure.
2. Withdraw the drive shaft, drive gear and gear
The pressure relief valve relieves the discharge pressure
retaining ball as an assembly from the pump body.
by by-passing the fuel from the outlet side of the pump to
the inlet side when the discharge pressure reaches
3. Press the drive shaft just far enough to remove the
approximately 65 to 75 psi (448 to 517 kPa).
steel locking ball. Then invert the shaft and gear
assembly and press the shaft from the gear. Do not
The fuel pump should maintain the fuel pressure at the
misplace the steel ball. Do not press the squared end of
the shaft through the gear as slight score marks will
damage the oil seal contact surface.
Remove Fuel Pump
4. Remove the driven shaft and gear as an assembly
1. Disconnect the fuel lines from the inlet and outlet
from the pump body. Do not remove the gear from the
openings of the fuel pump.
shaft. The driven gear and shaft are serviced only as an
assembly.
5. Remove the relief valve plug and copper gasket.
6. Remove the valve spring, pin and relief valve from the
valve cavity in the pump body.
Fig. 4 Removing Fuel Pump Cover 2.
Fig. 5 - Removing Oil Seals
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