Piper COMANCHE PA-24-180 Service Manual page 505

PIPER COMANCHE SERVICE MANUAL
C474
1 VALVE CAP
2 CRUSH WASHER
3 "O" RING
4 WASHER
5 SPRING
6 BRASS WASHER
7 POSITION WASHER
8 VALVE STEM
9 PIN
10 PLUG COCK
11 VALVE BODY
FIGURE 8-11. THREE POSITION FUEL VALVE PA-24-180 AND PA-24-250
and disconnect the wiring
d Remove the floor carpet and floor panel covering the selector.
e Disconnect the fuel lines
f
Remove the screws securing the v al e mounting plate. The forward screws are secured bv nuts while
the aft screws are secured by plate nuts Remove the salve from the aircraft
8:14 Servicing Three Position Fuel Valve. (PA-24-180 and PA-24-250) The three position valve should be
serviced every 400 hours or when there is an indication of valve binding The binding of this valve (refer to
Figure 8-11 ) is caused by fuel coming in contact with the plug and gradually removing the film of lubricant:
presence of foreign material or the use of improper lubricants
a
With the salve removed from the aircraft. remove the valve cap (I) and interior parts
b Inspect the position washer (7) inner perimeter surface for indications of wear: should this be
evident. replace washer
c. Check the condition of plug cock (8) and valve bod ( I ) for scored surfaces The surfaces. if not
bad l scored. mav be conditioned by lapping with a fine polishingcompound Clean aw a all compound after
lapping It plug cock will not seat properly or if scoring remains evident. the valve should be replaced.
d. Check the condition of the valve stem in the area where the "0" ring (2) seats. Should the stem be
worn or damaged so that the "0" ring will not seal. replace the valve
e With a I0x magnifying glass. inspect the valve plug cock for cracks. If cracks are visible. replace
valve
f
Clean the valve of all foreign matter, lubricate the dry plug with a light film of MIL-G-60312.
(Type I ) grease. turn the plug several times in its seat and wipe off any excess lubricant in the plug cock and
val'e ports. Lubricate position washer with a light film of MIL-G-6032 (Type 1) grease. Reassemble the valve
with a new "O" ring
REVISED: 11/1/82 _ __ FEL SYSTEM
2J3