Adjustment Of Hand Pump Relief Valve; Adjustment Of Main Relief Valve; Adjustment Of Priority Valve; Adjustment Of Door Solenoid Valve - Piper Navajo Chieftain PA-31-350 Service Manual

NAVAJO CHIEFTAIN SERVICE MANUAL
6-47. ADJUSTMENT OF HAND PUMP RELIEF VALVE.
a.
With the landing gear handle in either the up or down position, apply test unit pressure very
slowly until fluid flows from the hand pump relief valve.
CAUTION
It is very important that the test unit be operated very slowly as
pressure is being increased to bleed the hand pump relief valve. If
the test pump is operated rapidly, damage to the valve can occur
as air permits parts to "slam" against each other.
b.
Bleed air from the power pack by cracking the cap on the door-open fitting.
c.
Adjust the retainer plug at the top of the valve until the valve cracks at the pressure given in
Table VI-I (using a slow flow). Bleed pressure by cracking the cap on the door-open fitting after each
adjustment.
d.
Safety wire the hand pump relief valve to the time-delay valve.
6-48. ADJUSTMENT OF MAIN RELIEF VALVE.
a.
Loosen the locknut and back out the adjusting screw at the top of the valve until very little load
is left on the spring.
b.
With the landing gear handle in the down position, apply pressure until fluid flows from the
primary relief valve.
c.
Adjust the main relief valve until the valve cracks at the required pressure as given in Table VI-I.
Bleed pressure after each adjustment by cracking the cap on the door-open fitting. Tighten the locknut on
the adjusting screw after obtaining the correct adjustment.
6-49. ADJUSTMENT OF PRIORITY VALVE.
a.
Place the landing gear handle in the up position and remove the cap from the gear up fitting.
b.
Apply pressure and note the priority valve cracking pressure by observing the pressure gauge
when fluid first starts to flow from the gear-up port.
c.
Adjust the priority valve to crack at (refer to Table VI-I). Bleed pressure after each adjustment by
cracking the cap on the door-open fitting.
d.
Disconnect the test unit and cap all open fittings.
6-50. ADJUSTMENT OF DOOR SOLENOID VALVE.
a.
Remove the caps from the door-open and door-close fittings on power pack.
b.
Connect a test harness to the electrical plug of the power pack and power source. (A test harness
may be fabricated as shown in Figure 29.)
c.
With the test harness switch in the OFF position, and the landing gear handle in either the up or
down neutral position, apply pressure and note that fluid flows from the door-open fitting.
d.
With the test harness switch in either the gear up or down position, the landing gear handle in
either the up or down neutral position, apply pressure and note that fluid flows from the door-close fitting.
e.
Disconnect the test equipment and cap all open fittings.
Reissued: 9/23/80
2B16
HYDRAULIC SYSTEM