(c)
Dropballinto cavity of hand pumpreliefvalvebody.Installball seat intobody,trappingball betweentwoparts.

(d)Lubricatethreadsandinstallassemblyinto power packbody.Torqueto 70 inch-pounds.
(e)Insertstemand spring intovalvebody.Installadjustingscrew.Adjustingscrewprovidesadjustmentfor hand pumpreliefvalveandmustbeinstalledflush.
EFFECTIVITY: 040-999

PAGE24 0
Jan 10/9029-10-00
PIPER AIRCRAFT
PA-42-720 (Advanced Trainer)
MAINTENANCEMANUAL

A. Main (continued)
50. Adjustmentof Hand Pump Relief Valve (Figure 403, Item 51)
(a) With input shaft in gear UP or gear DOWN position, apply hand pump pressure very slowly until fluid flows from hand pump relief valve.
CAUTION: HAND PUMP MUST BE OPERATED SLOWLY WHILE INCREASING PRESSURE TO BLEED HAND PUMP RELIEF VALVE.
(b)
Bleed air from power pack by cracking cap on door open fitting.

(c)
Adjustscrew at top of valve until the valve cracks at 2025 -2100 psi (29-00-00, Chart2). Bleed pressureby cracking cap on door open fitting after each adjustment.

51. Disassembly of Hand Pump Suction Screen. (Figure 403, Item 48)
(a) Remove suction screen by removing snap ring.
52. Assembly of Hand Pump Suction Screen. (Figure 403, Item 48)
(a) Install filter into power pack body. Secure with snap ring.
53. Adjustment of Door Solenoid Valve. (Figure 404, Item 11)
(a)
Remove caps from door open and door close fittings on power pack.

(b)
Connect test harness to power pack electrical plug and to power source. (Test harness can be fabricated as shown in Figure 502.)

(c)
With test harness switchin OFF position andinput shaft in UP NEUTRALor DOWNNEUTRAL position, apply pressure and note fluid flows from door open fitting.

(d)
With test harness switch in gear UP or gear DOWN position, input shaft in UP NEUTRAL or DOWN NEUTRAL position, apply pressure and note fluid flows from door closed fitting.

(e)
Disconnecttest equipment. Cap all open fittings.

MS35058-21 or Equivalent Switch
Gear Up
MS3106A-145-25Plug MS3057A-6AClamp

Clamps GearDown
Wire:18Gauge Battery-HarnessLength:2 to 3 ft
PowerPack Test Harness Schematic
Figure502

EFFECTIVITY:
29-10-00Jan

PIPER AIRCRAFT
PA42-720(AdvancedTrainer)
MAINTENANCEMANUAL

A. Main(continued)
54. Disassemblyof Time Delay Check Valve.(Figure403, Item 59)
(a)
Removecheck valve body from power pack body.

(b)
Removesnapring.

(c)
Usingbrasshook, pull out seat.

(d)
Removeball and spring.

55.Assemblyof Time Delay CheckValve.(Figure403, Item 59)
(a)
Installspring and ball into check valve body.

(b)
Lubricateand install O-ringon seat.

(c)
Installseat into check valve body and secure withsnap ring.

(d)
Lubricatethreads and install O-ring on valve body. Install assembly into power pack body and torque to 45 inch-pounds.

56. Installationand Adjustment of Inboard Gear Doors Switch.
(a)
Installswitch assembly with insulating platebetweenthe switch and manifold. Secure lightly with washers and screws.

(b)
Moveselector spool to gear up and down positiona few times to ensure proper actuating of switchfromON to OFF. Torqueswitch screws to 20 inch-pounds.

(c)
Safety wire solenoid to bracket (Figure 404) using 0.032 inch safety wire.

(d)
Connectelectrical wires from switch to terminal block (Figure 403). Secure to solenoid with plastic strap.

NOTE: Electricalwiresarecolor coded andmustbe matched when reinstalling wires.

(e)
Install plungers, springs, and button into handle release bodies. Retain with snap rings.

(f)
Installhandle release assemblieslooselyin body.

57. Power Pack Bench Test Adjustment.
Aftercompletionof overhaul, bench test power pack prior to installation in airplane using hydraulic test unit or similar test equipment.
(a)
Useonly clean hydraulic fluid per MIL-H-5606.

(b)
Equipmentneededis as follows:
(1.) Test unit pump and hand pump with 2500 psi capacity.
(2.) One hydraulicpressuregaugewith 2500 psi capacity.
(3.) One hydraulicpressuregaugewith 200 psi capacity.

(c)
Connecttest pressure hoseto pressure inlet port of power pack. The 2500 psi gauge must operate off pressure line.

(d)
Connectsuctionhose to suction port of power pack.

(e)
Connectvent hose (if included) to vent port at top of reservoir-cover.

(f)
Cap all other fittings with high pressurecaps.
　
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