Piper SEMINOLE PA-44-180, Maintenance Manual

Page: 339 / 881

MAIN.
— NOTE —
PA-44-180, S/N’s 44-7995001 thru 44-8195026, and all PA -
4 4 -180T’s were equipped with Prestolite hydraulic pumps. PA-
44-180, SN’s 4495001 and up were equipped with Oildyne
hydraulic pumps. Prestolite pumps may be replaced with
Oildyne pumps. No repair is authorized of the Oildyne
Hydraulic Pump
— NOTE—
It is the users responsibility to refer to the applicable vendor
publication when servicing or inspecting vendor equipment
installed in Piper airplanes.
PRESTOLITE HYDRAULIC PUMPS.
REMOVAL OF PRESTOLITE HYDRAULIC PUMPS.
The hydraulic pump with reservoir incorporated is located in the aft section of the fuselage between
s t ations 156 and 191. Access to the pump is through the access panel in the baggage compartment.
1 . Disconnect the pump electrical leads from the pump solenoid relays and the ground wire from the
b a ttery shelf. Mark electrical leads to facilitate installation.
2. Disconnect the hydraulic lines from the pump. Cap the line ends to prevent contamination.
3. Remove pump by removing pump attaching bolts.
4. Cap or plug all ports.
5. Clean exterior of pump using a dry cleaning solvent to remove accumulated dirt and dust.
DISASSEMBLY OF PRESTOLITE HYDRAULIC PUMP (Refer to Figure 29-3.)
It is recommended that faulty Prestolite hydraulic pumps be sent to an accredited overhaul facility for dis-
assembly and repair.
The major components of the pump assembly are the pump base, pump motor, and valve, reservoir, and
gear case. To disassemble the major components:
1. Remove pump base from valve and gear case by:
A. Cutting safety wire and removing bolts with washers securing pump base to pump and gear case.
B. The check valve within the pump base should be removed for cleaning purposes only. To remove
valve, cut safety wire and remove bolt, spring and steel ball. Replace O-ring at reassembly.
2. Remove pump motor from the pump and disassemble as follows:
A. Remove thru bolts from head of motor. Using a knife cut the seal coating between the motor head
and case.
B. Lift the head up from the case approximately 0.50 of an inch. This will allow inspection of brushes
without the brushes unseating from the commutator. (Refer to the next paragraph for brush
inspection.) The brush leads are secured to the head assembly.
C. Raise the head assembly off the armature and note the small thrust ball located between the end of
the armature and motor head. Do not misplace this bearing.
D. Draw the armature from the motor frame. Note the number of thrust washers mounted on the
drive end of the armature shaft.
E. Remove the motor frame from the pump reservoir.
PIPER AIRCRAFT
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
29-11-02
Page 29-12
Revised: June 20, 1995
2C7