Piper Navajo PA-31 Service Manual page 616

PIPER NAVAJO SERVICE MANUAL
9-40. ELECTRIC FUEL PUMP. (PA-31-310 and 325)
9-41. REMOVAL OF ELECTRIC FUEL PUMP. (Refer to Figure 9-9.) Instructions given
are for the removal of the electric fuel pumps from the airplane for the purpose of cleaning,
inspection, replacement or repair and adjustment.
a. Turn the fuel selector to the OFF position.
b. Remove the access panel forward of the main spar. between the underside of the
wing and the fuselage.
c. Disconnect the electrical leads to the fuel pump.
d. Disconnect the fuel lines from the fuel pump and filter assembly. Cover the line ends
to prevent contamination.
e. Remove the bolts that secure the pump and filter to their mounting brackets and
remove from the airplane.
f. Separate the fuel pump from the filter.
9-42. DISASSEMBLY OF ELECTRIC FUEL PUMP. (Refer to Figure 9-12.) The motor of
the A1OOOOD pump assembly may be separated from the pump by removing the two motor
thru bolts located inside the cover at the commutator end of the motor. The motor of the
A10014C pump assembly may be separated from the pump by removing the four motor
attachment screws (33). Care should be taken when separating the pump from the motor to
insure that the shaft end bearing. which is a press fit on the armature shaft, slips out of the
pump body housing. After separation of the pump and motor, disassembly of the pump can
proceed as follows:
a. Remove seal spring (19), seal washer (18) and seal cage (14) containing seal 'O" ring
from pump shaft. Long thin nose pliers may be used to facilitate removal of seal cage.
b. Unscrew the insert plug (2) with "O" ring seal (21) from the pump body (1).
Remove the wear plate spring (26) and wear plate (25) (used with newer pumps).
c. Insert No. 5-40 screws into tapped hole or face of insert (3) and pull insert assembly
from pump body. If necessary, pry the insert loose from the pump body using a lever arm
between the pump body and screw head.
d. Remove rotor (4) from insert by pushing on the end of rotor shaft. Remove blade
retaining spring (5) and blades (17). Also "O" ring seals (22).
e. Using a light arbor press, apply pressure to valve adjusting screw (10) to release
tension against the Tru-Arc retaining spring (12) and remove the spring with Tru-Arc pliers.
Pull out adjustment guide (9) containing "O" ring seal (16), adjusting screw (10) and
locknut (11).
f. Remove the valve spring (8) and piston assembly (7).
g. Remove the bearing retainer insert (24) from pump body, when required, by means
of an arbor press.
Reissued: 10/12/79
FUEL SYSTEM
3B24