Piper Navajo PA-31 Service Manual page 330

PIPER NAVAJO SERVICE MANUAL
6-46. ADJUSTMENT OF HANDLE-RELEASE MECHANISM. (Refer to Figure 6-16.) The following
procedure
outlines preliminary adjustments to set the handle-release detent spring load and the
handle-return spring load adjusting plugs in approximately their correct positions before installing the
Power Pack in the airplane. After it has been installed, the system must be checked and final adjustments, if
needed, made at that time. Use a .078 inch punch to rotate the gear handle shaft.
a. Ascertain that the handle-return spring adjusting plugs (I and 2) are not tightened, and the detent
spring adjusting plug (3) has been screwed in until approximately .312 inch of thread is engaged. The
spring, however, must not bottom out.
b. Place the handle in the up-detent position, then hold it beyond this position (in overtravel).
c. Tighten the forward handle-return spring adjusting plug (2) until the handle just starts to move
out of overtravel, then loosen the adjusting plug one turn.
d. Place the handle in the down-detent position, then hold it beyond this position (in overtravel).
e. Tighten the aft handle-return spring adjusting plug (1) until the handle just starts to move out of
overtravel, then loosen the adjusting plug one turn.
f. Place the handle in the up-detent position and tighten the handle-release detent spring adjusting
plug (3) until the spring bottoms out, then back the adjusting plug out two turns.
g. The handle must hold in both detent positions, but must return with a positive snap when
manually released from either detent position. Connect a spring scale to the arm and pull both fore and aft,
perpendicular to the centerline of the arm, to determine that it will leave the detent at a force of 9 + 1-2
pounds. The handle-release detent spring adjusting plug (3) may be readjusted slightly more or less than the
two turns specified in the preceding step, if necessary. When proper detent adjustment has been obtained,
tighten the nuts and safety.
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 stated 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 main
relief valve.
c. Adjust the main relief valve until the valve cracks at the pressure stated 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.
Reissued: 10/12/79
HYDRAULIC SYSTEM