Piper Cherokee Six - Page 220

PIPER CHEROKEE
SIX SERVICE
MANUAL
c.
Remove
pump
by removing
pump attaching
bolts.
5A-6. DISASSEMBLY
OF HYDRAULIC PUMP. (Refer
to Figure 5A-3.) After the hy-
draulic pump
has been removed
from the airplane,
cap or plug all ports,
and clean exterior
of
pump using
a dry cleaning
solvent to
remove accumulated
dirt
and dust.
The three major
components
of the pump assembly
are the pump
base, pump motor,
and valve and gear
case.
These three
major components
should
be disassembled
as follows:
a. Pump
Base:
Remove
pump
base
(16) from
valve
and gear
case
by:
1. Cutting
safety wire
and removing
bolts (17)
with washers
securing
pump base
to
pump
and
gear
case.
2.
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.
b. Pump
Motor:
The pump
motor
may be removed
from
the pump
and
disassembled
as
follows:
1.
Remove thru
bolts (4)
from head
(1) of motor.
Using a knife
cut the
seal coating
between
the motor
head and case.
2.
Lift the head
up from
the case approximately
.50 of an inch,
this will
allow inspec-
tion
of brushes (3)
without the
brushes unseating
from the
commutator.
(Refer to
Paragraph
5A-7
for brush inspection.)
The brush
leads are secured
to the head
assembly.
3. Raise the
head assembly
(1) off
the armature
(8) and note
the small
thrust ball
(7)
located between
the end
of the armature
(8) and motor
head.
Do not misplace
this bearing.
4. Draw
the armature
from
the motor
frame
(9). Note
the number
of
thrust washers
(11) mounted
on the
drive end
of the
armature
shaft.
5. Remove
the motor
frame
from the
pump
reservoir
(13).
c. Valve
and Gear Case:
Remove
valve and gear
case (15)
from reservoir
(13) as follows:
1.
Remove eight
screws
from flange
of body and
separate
the two assemblies
(18).
2.
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
identi-
fied with their
cavities; otherwise,
it will
be necessary
to readjust
each valve for
proper operat-
ing pressure.
5A-7. CLEANING, INSPECTION AND REPAIRS OF HYDRAULIC PUMP.
NOTE
Repair
facilities
must
be clean
to prevent
contamination
of
pump
components.
Proper
and
careful
handling
should
be
exercised
to prevent
damaging
pump
components.
a. Discard
all O-rings.
b. Remove
caps
or plugs
and clean
all components
with
a dry type
cleaning
solvent
and
dry thoroughly.
c. Inspect
pump
components
for scatches,
scores,
chips,
cracks
and
wear.
d. Inspect
motor
for worn
brushes (minimum
of.218 brush
remains
between
the braided
wire and commutator
end), excess wear and excess
bearing wear.
Added:
9/18/78
HYDRAULIC
SYSTEM
1J4