Piper Cherokee Six - Page 219

PIPER
CHEROKEE
SIX
SERVICE
MANUAL
CAUTION
Prior
to
starting
any
investigation
of
the
hydraulic
system,
place
the airplane
on jacks.
With
the
airplane
on
jacks,
pull
the
emergency
extension
lever
up
and
latch
in
override
position
thus
preventing
the
buildup
of
unnecessary
pressure
on
the
actuating
cylinders
and
connecting
hydraulic
lines
when
the
gear
is
raised
or lowered
manually.
Failure
to
comply
with
these
instructions
could
result
in
the
buildup
of
sufficient
pressure
to
unlock
the
downlock,
mechanism
allowing
the
gear
to
collapse
when
the
wing
jacks
are
removed.
Prior
to
removing
the
airplane
from
jacks,
push
the
emergency
extension
lever
down,
turn
on
the
master
switch
and
select
gear
down,
observe
that
all
three
green
lights
indicating
the
landing
gear
is
down
and
locked
are
energized.
Turn
master
switch
off.
5A-3.
TROUBLESHOOTING.
Malfunctions
in the
hydraulic
system
will
result
in failure
of
the
landing
gear
to
operate
properly.
When
trouble
develops,
jack
up
the
airplane
(refer
to
Jacking,
Section
II)
and
then
proceed
to
determine
the
extent
of
the
trouble.
Generally,
hydraulic
system
troubles
fall into
two
types,
troubles
involving
the
hydraulic
supplying
system
and
troubles
in the
landing
gear
hydraulic
system.
Table
VA-III
at the
back
of this
section,
lists
the
troubles
which
may
be encountered
and
their
probable
cause,
and
suggests
a remedy
for
the
trouble
involved.
A
hydraulic
system
operational
check
may
be
conducted
using
Figures
5A-1
or
5A-2.
When
the
trouble
has
been
recognized,
the
first
step
in
troubleshooting
is isolating
the
cause.
Hydraulic
system
troubles
are
not
always
traceable
to
one
cause.
It
is
possible
that
a malfunction
may
be
the
result
of more
than
one
difficulty
within
the
system.
Starting
first
with
the
most
obvious
and most
probable
reasons
for
the
trouble,
check
each
possibility
and,
in
turn,
by
process
of elimination,
isolate
the
troubles.
NOTE
If
it is
found
that
the
hydraulic
pump
is at
faultand
requires
disassembly,
it
is
recommended
that
it
be
overhauled
by
an
accredited
overhaul
facility.
Pressure
checks
with
adjustments
may
be
accomplished
in
accordance
with
instructions
given
in
Paragraphs
5A-6
thru
5A-9.
5A-4.
HYDRAULIC
PUMP.
5A-5.
REMOVAL
OF
HYDRAULIC
PUMP.
The
hydraulic
pump
with
reservoir
incorpo-
rated
is
located
in
the
nose
section
of
the fuselage.
Access
to
the
pump
is
through
the
access
panel
in
the
nose
baggage
compartment.
a.
Disconnect
the
pump
electrical
leads
from
the
pump
solenoid
relays
and
the
ground
wire
from
the
battery
shelf.
b.
Disconnect
the
hydraulic
lines
from
the
pump.
Cap
the
line
ends
to prevent
contam-
ination.
HYDRAULIC
SYSTEM
Revised: 9/18/78
1J3