Assembly Of Hand Pump; Installation Of Hand Pump; Bleeding Hand Pump; Hand Pump Test - Piper Navajo Chieftain PA-31-350 Service Manual

NAVAJO CHIEFTAIN SERVICE MANUAL
6-108. ASSEMBLY OF HAND PUMP. (Refer to Figure 6-20.)
a.
To install the plunger assembly, first install the check ball assembly in the plunger by placing
O-ring packing (8) on seat (9). Lubricate the seat (9) with hydraulic fluid, MIL-H-5606, and install check
ball spring (11), check ball (10) and seat (9) in the end of the plunger. Install snap ring (7) to secure parts in
place.
b. Install O-ring packing (12) on the plunger.
c. Install O-rings (14 and 16) on the exterior and in the interior of the packing gland (15).
d. Lubricate the packing gland and plunger assemblies. Slide the packing gland onto the small end of
the plunger (13) with the recessed end toward the small end of the plunger and insert the plunger with the
packing gland (15) into the pump body (16).
e.
Position the scraper (17) on the plunger (13), with the flat end toward the gland (15), and slide it
into the pump body (6).
f. Attach the bracket (18) to the pump body (6), install Allen screws and safety with MS20995C20
lock wire.
g. Position link (20) and install pins (22 and 23), washers (31) and cotter pins (2).
h. To install the check ball assembly in the suction port of the pump body, install O-ring (2) on ball
seat (3). Lubricate the seat assembly with hydraulic fluid, install spring (5), check ball (4), seat (3) and
secure in place with snap ring (1).
6-109. INSTALLATION OF HAND PUMP.
a. Position the hand pump on its mounting bracket and secure with bolts.
b.
Connect the hydraulic pressure and suction lines to the forward end of the pump.
c.
Bleed the hand pump as described in Paragraph 6-110 and test the hand pump as described in
Paragraph 6-111.
d. Install access panel.
e.
Ascertain that hydraulic reservoir is full.
6-110. 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.
6- 111. HAND PUMP TEST.
a.
Ascertain that the reservoir is filled with hydraulic fluid.
b.
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.
c.
After pump is primed and bled of all air, remove fitting and install 3000 psi gauge at door-open
port.
d.
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 (refer to Table VI-I.) During the pumping operation, the
emergency hand pump should not feel spongy in either the up or down stroke.
e.
Crack gauge in door-open port to release pressure, remove gauge, reinstall the cap door-open
fitting, and drain fluid from reservoir.
Reissued: 9/23/80
HYDRAULIC SYSTEM
2C13