Cleaning, Inspection And Repair Of Cross-Feed Valve; Leak Test Of Cross-Feed Valve - Piper Navajo PA-31 Service Manual

PIPER NAVAJO SERVICE MANUAL
9-22. CLEANING, INSPECTION AND REPAIR OF CROSS-FEED VALVE.
a. Clean the valve components in a suitable cleaning solvent.
b. Inspect the valve for the following:
1. Check that the friction surfaces of the valve body and stem are free
from nicks, dents and burrs.
2. Check that the inner and outer seals are not worn so much as to allow
the valve stem to misalign in the valve seat.
(For replacement of inner and out-
er seal, return to Scott.)
3. Check that the threaded surfaces of the seat fitting are not stripped or
cross-threaded.
c. Repair to the valve is limited to reconditioning of parts, such as smoothing
out minor nicks and scratches, and the replacing of "O" ring packings.
NOTE
Fitting (4) in valve is special. Do not use AN fittings.
9-23. ASSEMBLY OF CROSS-FEED VALVE. (Refer to Figure 9-7.)
a. If seat valve (4) was removed, install the "O" ring packing (6) and assem-
ble the seat fitting on the valve body (3).
b. Lubricate the "O"' ring packings with a thin coat of stop-lock grease and
install.
c. Push the stem (2) into the valve.
d. Connect the control arm (10) with the stem and secure with pin (8) and nut
(9).
e. Check valve operation.
9-24. LEAK TEST OF CROSS-FEED VALVE.
a. Connect one port of the valve to a 50 psig air source.
b. Close valve, apply pressure to 50 psig and submerge in kerosene or a
similar petroleum base fluid for two minutes.
c. Depressurize and connect the air source to the other port of the valve.
d. Repeat step b.
e. There shall be no evidence of leaking through the valve seat or around the
valve stem.
f. Disconnect and wipe fluid from exterior.
Reissued: 10/12/79
3B14
FUEL SYSTEM