Piper Cherokee Six - Page 215

PIPER CHEROKEE
SIX SERVICE
MANUAL
SECTION
VA
HYDRAULIC
SYSTEM
PA-32R-300
5A-1.
INTRODUCTION.
The
PA-32R-300
hydraulic
system
components
covered
in this
section
consist
of
the combination
hydraulic
pump
and
reservoir,
gear back-up
extender
actuator
assembly,
actuating
cylinders
and
hydraulic
lines.
The brake
system,
although
hydraulically
operated,
is not
included
in this
section
as
it has
its own
hydraulic
system
independent
of
the gear
retraction
system.
The
brake
system
along with
the
landing
gear and
components
is covered
in Section
VIA.
This section
provides
instructions
for remedying
difficulties
which
may
arise
in the
operation
of
the hydraulic
system.
The
instructions
are
organized
so
that the
mechanic
can
refer
to: Description
of
the System,
for a
basic
understanding
of the
system;
Troubleshooting,
for
a methodical
approach
in locating
difficulty;
Corrective
Maintenance,
for the
removal,
repair
and
installation
of components;
and
Adjustments
and
Checks,
for
the
operation
of the
repaired
system.
CAUTION
Prior
to starting
any
investigation
of the
hydraulic
system,
place the
airplane
on jacks. (Refer
to Jacking,
Section
II.)
5A-2.
DESCRIPTION.
Hydraulic
fluid
to the
landing
gear actuating
cylinders
is supplied
by
an electrically
powered
reversible
pump
located
below
the
raised
floor
in the forward
baggage
compartment
at station
45.
A reservoir
is
also an
integral
part of
the pump.
The
pump
is controlled
by a
selector
switch
on the
instrument
panel
to the
left of
the control
quadrant.
As the
switch
is placed
in
either the
up or
down
position,
the pump
directs
fluid
through
the
particular
pressure
line
to each
individual
actuating
cylinder.
As fluid
pressure
increases
at
one side
of a cylinder
piston, fluid
at
the other
side is
directed
back
through
the
other
line to
the pump.
Both
lines
serve either
as pressure
or return
passages
depending
on
the rotation
of
the pump
to
retract
or extend
the gear.
A
pressure
switch
is installed
on
a cross
fitting connected
to the
pump mount
assembly.
During retraction
the pressure
switch
is the primary
means
to shut
down
the
pump.
This
switch
opens the
electrical
circuit
to the pump
solenoid
when
the gear
fully
retracts
and
the pressure
in the
system increases.
The
switch
will continue
to hold
the circuit
open
until
pressure
in the system
drops
when at
that time
the pump
will again
operate
to
build
up pressure
as
long as the
gear selector
handle
is in the
up position.
The
down position
of
the selector
does
not affect
the pressure
switch.
(For
Specific
Pressures
refer to Table
VA-I.)
Revised:
7/29/77
HYDRAULIC
SYSTEM
1123