Piper Navajo PA-31 Service Manual page 357

PIPER NAVAJO SERVICE MANUAL
e.
To remove the check ball assembly located in the suction port, reach into the port with a pair of
long snap ring pliers and remove the snap ring (1). With a low charge of air injected into the interior of the
pump body, blow the seat (3) and check ball from the suction port. Remove the spring (5).
6-111. CLEANING. INSPECTION AND REPAIR OF HAND PUMP.
a.
Clean the pump parts with a suitable solvent and dry thoroughly.
b. Inspect the pump body for scratches. burrs. etc.. that could damage "0" rings and threaded areas
for damage.
c. Inspect pump handle assembly for signs of corrosion at the attachment point. If corrosion is
evidenced or present. replace the handle assembly
d.
Inspect the plunger for enlarged pinhole. surface area for scratches. burrs. etc.. that could damage
"0" rings.
e. Inspect check balls and seats for damaged seating areas and corrosion.
f. Check general condition of remaining parts.
g. Repairs to the pump are limited to polishing out small scratches, burrs. etc.. replacing "O" rings
and worn or damaged parts.
6-112. ASSEMBLY OF HAND PUMP. (Refer to Figure 6-26.)
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 "0" 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 (25).
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).
6-113. 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 6-114 and test the hand pump as described in
Paragraph 6-115.
d. Install access panel.
e. Ascertain that hydraulic reservoir is full.
6-114. 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.
6-115. 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. install 3000 PSI pressure 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.
Revised: 3/2/84
HYDRAULIC SYSTEM
2D3