Piper SEMINOLE PA-44-180, Maintenance Manual

Page: 341 / 881

3. Remove valve and gear case from reservoir as follows:
A. Remove eight screws from flange of body and separate the two assemblies.
B. Pump gears and valves should be removed for cleaning purposes only. To remove cap securing
Gears, remove attaching bolts. The two valve springs should be positively identified with their
cavities; otherwise, it will be necessary to readjust each valve for proper operating pressure.
CLEANING, INSPECTION AND REPAIR OF PRESTOLITE HYDRAULIC PUMP
— CAUTION —
R E PAIR FACILITIES MUST BE CLEAN TO PREVENT
CONTAMINATION OF PUMP COMPONENTS. PROPER
AND CAREFUL HANDLING SHOULD BE EXERCISED
TO PREVENT DAMAGING PUMP COMPONENTS.
1. Discard all O-rings.
2. Remove caps or plugs and clean all components with a dry type cleaning solvent and dry thoroughly.
3. Inspect pump components for scratches, scores, chips, cracks and wear.
4. Inspect motor for worn brushes (minimum of .218 of an inch brush remains between the braided and
commutator end), excess commutator wear and excess bearing wear.
5. Repairs are limited to O-ring and brush replacement as follows:
A. One brush holder has the winding wire attached. Locate this wire and remove by using a solder-
ing gun.
B. The head assembly can now be removed and worked on for ease of brush replacement if required.
C. Remove brush wire and brush from bimetal heat protector.
D. Solder new brush wires to head assembly and bimetal heat protector, and wire from winding to
one brush holder.
E. Install brush springs and brushes into brush holders and secure in place (temporary) with a piece
of string looped around the brush and holder and tied in a knot.
— NOTE —
Ensure that the braided wire is in the holder slot for proper brush
movement.
F. Install the head assembly with new brushes to the frame and commutator in accordance with
instructions given in Step I of the next paragraph.
ASSEMBLY OF PRESTOLITE HYDRAULIC PUMP (Refer to Figure 29-3.)
1. To assemble pump motor and install on reservoir:
A. Position motor frame on reservoir. Note aligning marks on frame and reservoir.
B. Place thrust washers, of the same amount removed, on the drive end of the armature.
C. Lubricate the entire length of the armature shaft, on the drive end, with light grease to protect 0-
ring seal from damage. Insert end of shaft in reservoir.
D. Saturate felt oiling pad around commutator end bearing with SAE 20 oil. Allow excess oil to
drain off before assembling motor.
E. Insert thrust ball in bearing of motor head. To hold ball in position, place a small amount of
grease inside the bearing.
F. Place head assembly on frame and allow brushes to extend over commutator. Remove the string
securing the brushes in the holders. Push head assembly on frame and insure proper indexing of
head and frame assemblies. Secure in place with thru bolts.
PIPER AIRCRAFT
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
29-11-04
Page 29-14
Revised: June 20, 1995
2C9