Bleeding Hand Pump; Hand Pump Test; Removal Of Shuttle Valves - Piper PA-31-350 Maintenance Manual

PIPER AIRCRAFT
T-1020
MAINTENANCE MANUAL
4.
Install access panel.
5.
Ascertain that the reservoir is filled with hydraulic fluid.
BLEEDING HAND PUMP.
The hand pump may be purged by operating the pump until all air has been expelled from the pump. This
will usually require approximately 15 cycles of the pump.
HAND PUMP TEST.
1.
Ascertain that the reservoir is filled with hydraulic fluid.
2.
Remove cap from door-open port and operate emergency hand pump until fluid flows from port
with no evidence of air in the system. Replenish reservoir with clean hydraulic fluid as necessary to maintain
fluid level.
3.
After pump is primed and bled of all air. install 3000 psi pressure gauge at door-open port.
4.
Operate emergency hand pump very slowly until pressure on gauge stops increasing, indicating that
the hand pump relief valve has opened.
- CAUTION -
It is very important that the hand pump be operated very slowly as
pressure is being increased to bleed the hand pump relief valve. If the
hand pump is operated rapidly, damage to the valve can occur as air
permits parts to "slam" against each other.
Maximum indication of the gauge should be as indicated in Chart 2902. During the pumping operation.
the emergency hand pump should not feel spongy in either the up or down stroke.
5.
Crack door-open fitting to release gauge pressure. Remove gauge. cap door open fitting
and drain fluid from reservoir.
- NOTE-
A t the completion of the test, the line should be reinstalled and the
fluid level in the reservoir checked.
REMOVAL OF SHUTTLE VALVES.
Shuttle valves are located on the gear actuator cylinders and main gear door actuator cylinders and may
be removed as follows.
1.
Place airplane on jacks. (Refer to Jacking, Chapter 7)
2.
Disconnect hydraulic lines and cover open line ends to prevent contamination.
3.
Remove valve from cylinder and cover opening on cylinder to prevent contamination.
29-21-08
29-48
Revised: November 17, 1983
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