Piper Navajo PA-31 Service Manual page 309

PIPER NAVAJO SERVICE MANUAL
6-8. CONNECTING TEST UNIT. There are two methods of connecting the hydraulic test unit to
the
airplane.
1.
Early Model Airplanes:
a. Remove the lower engine cowl. (Refer to Removal of Engine Cowl, Section VIII.)
b.
Disconnect the engine driven hydraulic pump suction hose from the fitting at
the engine
fire wall and connect the suction hose of the test unit to the fitting. Cap the disconnected
suction hose.
c.
Disconnect the engine driven hydraulic pump pressure hose from the inlet side
of the
hydraulic filter on the fire wall and connect the pressure hose of the test unit.
Cap the disconnected
pressure hose.
d. Operate the test unit per instructions supplied with it.
2.
Later Model Airplanes:
a.
Remove the access panel on the right side of the nose section.
b. If the system requires filling only, remove the protective cap from the suction,
fill and drain
valve and connect the pressure hose from the test unit. Open the valve on the suction
port and by placing
the control lever in the up position, proceed to fill the system per instructions with
test unit. Observe the
sight gauge on ozone power packs only, to determine when the reservoir is full or stop filling
operation when
fluid is seen draining from the overflow.
c.
If the system must be operated during various ground checks, overhaul, or inspection
of its
components, remove the protective caps from both the suction and the pressure
ports and connect the test
unit pressure hose to the pressure port and the test unit suction hose to the suction
port. Open the valve on
the suction port and proceed to operate the test unit according to instructions furnished
with it.
6-9. CYCLING LANDING GEAR.
a.
Connect hydraulic test unit in accordance with Paragraph 6-8 and jack the airplane
as outlined in
Section II.
b.
Set hydraulic test unit bypass valve open.
c. Start test unit pump motor.
d. Slowly close bypass valve completely.
e.
Using landing gear control handle in airplane, operate gear as desired.
NOTE
Gear cycling time can be prolonged by slowly opening the test
unit bypass valve part way. This will bleed off part of the pump
flow.
f.
After completion of cycling, ascertain that the landing gear selector handle is in the
down neutral
position, and that the landing gear is down and locked.
g.
Disconnect hydraulic test unit in accordance with Paragraph 6-17.
h. Remove the airplane from jacks.
CAUTION
When cycling the landing gear DO NOT use the manual hand pump
located between the pilot and copilot seats for this operation.
Revised: 10/12/83
HYDRAULIC SYSTEM
2B3