Piper Navajo PA-31 Service Manual page 621

9-47. INSTALLATION OF ELECTRIC FUEL PUMP.
a. Connect the fuel pump and fuel filter. Tighten the jam nut on the fitting between
the pump and filter to allow the "0" ring to seat on the non-threaded portion of the fitting.
b. Position the fuel pump and filter on the mounting brackets and secure with bolts.
c. Connect the fuel lines to the pump and filter.
d. Connect the electrical wires to the pump motor. (Black wire is ground wire.)
e. Turn on the fuel valve and check for fuel leaks.
f. Install the access plate and secure it.
9-48. ELECTRIC FUEL PUMP. (PA-31-300.)
949. REMOVAL OF ELECTRIC FUEL PUMP. (Refer to Figure 9-9a.) 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. (Identify leads to facilitate
reinstallation.)
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.
9-50. DISASSEMBLY OF ELECTRIC FUEL PUMP. (Refer to Figure 9-12a.) The electric
motor furnished with this pump is not economical to overhaul or service, therefore,
replacement with a new motor is recommended.
a. Using a light arbor press, apply pressure to valve adjusting screw (13) to release
tension against the Tru-Arc retaining ring (15) and remove the ring with Tru-Arc pliers. Pull
out the adjusting guide (12) containing "O" ring seal ( 11), adjusting screw (13) and locknut
(14).
b. Remove the valve spring (10) and piston assembly.
c. The shaft seal (2) can be pried loose from the insert (3) without disassembly of the
pump (4) by removing the motor (1) from the pump body (4).
Reissued: 10/12/79
3
FUEL SYSTEM
3C5
PIPER NAVAJO SERVICE MANUAL