ITEM  INSPECTION  REPAIR 
(Figure410) 
RearSide  Visuallyinspectlappedface for scratches or scoring.  Lap surfaceto removeany scratches. 
Centerplate  Visually inspect two lapped facesfor scratches or scoring. Inspectgear pockets fordeep scratches.  Lightlystoneanyburrsaround gearpockets. Lap faces,but do not remove more than 0.0001 inch total metalfrom both sides. 
DriveSide  Visuallyinspectlapped surfacefor scratches or scoring.  Lap surface to removeany scratches.If deep scratches exist, replace part. 
SecondaryShaft  Inspectshaftfor deep scratchesin bearing area.  Ifdeepscratchesexist, replace secondary shaft. 
Gears  Visuallyinspect gears for  Ifgears are not within 
chippedteethor cracks aroundbore. Measure gearO.D.,whichmust be  tolerance,orif any cracked teethexist, replace pump. 
1.1646-1.1644 inch. 
Bearings  Visuallyinspectbearing  Ifbadly scored, replacepump. 
bores for scratchesor 
scoring. 

NOTE: Use PA-42-720 (AdvancedTrainer)PartsCatalog,P/N761 818, to obtainrepairkitsforservicing pump.
EFFECTIVITY:

040-999 Jan 10/9029-10-00
Jan 10/90
PIPER AIRCRAFT
PA-42-720 (Advanced Trainer)
MAINTENANCEMANUAL

A. Main (continued)
68. Installationof Hydraulic Pump.
(a)
Place new gasket on base of housing.

(b)
Lubricate pump shaft splines with Molybdenum Disulfide type G paste lubricant.

NOTE: Drain fitting must face to lower right in downward position when installing pump.

(c)
Install pump on housing.

(d)
Lineup shaft splines with gear inside engine housing.

(e)
Installflat washers, lock washers, andnuts on base of pump; tighten.

(f)
Install two hydraulic hoses and prime pump before completing hookup to firewall fittings.

(g)
Ensure system reservoircontains proper amountof clean hydraulic fluid.

(h)
Changesystem fluid filters.

69. Priming Hydraulic Pump.
When pump is serviced or replaced, prime hydraulic pump to assure it does not operate in dry condition as follows:
(a)
Remove hydraulic suction and pressure lines from firewall fittings.

(b)
Install caps on suction and pressure fitting at firewall to prevent fluid loss prior to hookup of hydraulic lines.

(c)
Hold both lines higher than pump. Pour hydraulic fluid (MIL-H-5606) into lines.

(d)
One by one, remove caps from firewall fittings and connect appropriate line to fitting. Do not spill hydraulic fluid previously put in lines.

(e)
Afteroperating engine, check hookup for leaks.

70.Hand Pump (Emergency).
(a) Removalof hand pump. (1.) Remove pump access panel aft of control pedestal. (2.) Disconnect hydraulicpressureand suction lines from forward end of pump. (3.) Removepumpfrom mounting bracket by removing attachmentbolts. (4.) Remove pump from airplane. (5.) Cover pressureand suction lines to prevent contamination.
71. Disassemblyof Hand Pump. (Figure 411)
(a) Removeplunger and componentparts by removing quickclick pin and four screws. Allow bracket to separate from pump body.
NOTE: To remove quick click pins, use hollow steel rod with outside diameterof 0.186 -0.184 inch and inside diameter (bore) of 0.166 inch.
(b)
Pullplunger assembly from pump body.

(c)
Slidescraper and gland from plunger.

(d)
Removecheck valve assembly fromplunger by removing snapring from plunger cavity. Inject low charge of air into hole in plunger side to remove seat, ball, and spring.

(e)
Removecheck valve assembly in pump bodysuction port by removing snap ring. Inject low charge of air into pump body plunger boreto remove seat, ball, and spring.

EFFECTIVITY:

29-10-00Jan

PIPER AIRCRAFT
PA-42-720(Advanced Trainer)
MAINTENANCEMANUAL

A. Main (continued)
Handle Assembly 
30. Stop 
26. 
22. Screw  . 20.  1. Snap Ring 

Hand Pump
Figure 411

EFFECTIVITY:
040-999

PAGE3429-10-00
Jan 10/90
PIPER AIRCRAFT
PA-42-720 (Advanced Trainer)
MAINTENANCEMANUAL

A. Main (continued)
72. Assemblyof Hand Pump. (Figure411) prior to assembly
Lubricateall parts with oil (MIL-H-5606) as follows:
(a) Referto Cleaning, Inspection, and Repair of Hand Pump prior to assembly.
(b)LubricateO-ring and install on seat.
(c)
Install spring, ball, and lubricated seat into plunger.Retainwithsnap ring.

(d)
Install GT-ring on plunger.

(e)
InstallO-ring and back up into inside groove of gland.

(f)
　
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