Piper Cherokee Six - Page 503

PIPER
CHEROKEE
SIX
SERVICE
MANUAL
9-13.
REMOVAL
AND
REPLACEMENT.
a.
To
remove
the
regulator
valve;
disconnect
the
three
lines,
remove
the
mounting
screws
and
remove
the
valve.
b.
Replace
regulator
in
reverse
order
given
for
removal.
Check
complete
vacuum
system
for
proper
operation.
9-14.
VACUUM
PUMP.
9-15.
GENERAL.
The
vacuum
pump
is
of
the
rotary
vane,
positive
displacement
type.
This
unit
consists
essentially
of
an
aluminum
housing
containing
a
tempered
sleeve
in
which
an
offset
rotor,
with
moving
blades,
is
incorporated.
This
assembly
is
driven
by
means
of
a
coupling
mated
to
the
engine
driven
gear
assembly.
The
pump
is
mounted
on
the
accessory
section
of
the
engine.
9-16.
TROUBLESHOOTING.
For
troubleshooting
of
the
pumps,
refer
to
Table
IX-I
of
this
section.
9-17.
REMOVAL
AND
REPLACEMENT.
The
vacuum
pump
can
be
removed
by
the
following
procedure:
a.
Remove
the
top
portion
of
the
engine
cowling.
b.
Loosen
the
hose
clamp
and
remove
the
hose
from
the
vacuum
pump
fitting.
c.
Remove
the
vacuum
pump
by
removal
of
the
four
retaining
nuts.
lockwasher
and
plain
washers.
d.
Reinstall
pump
in
reverse
order
of
removal,
noting
alignment
of
spline
on
the
pump
drive
with
the
spline
on
the
engine
drive
assembly.
CAUTION
The
only
dry
air
pump
mounting
gasket
authorized
and
approved
for
use
on
the
Airborne
dry
air
pump
is
the
Airborne
gasket
B3-1-2,
Piper
part
number
751
859.
Use
of
any
other
gasket
may
result
in
oil
seepage
or
leakage
at
the
mounting
surface.
9-17a.
REPLACING
PUMP
FITTINGS.
a.
The
handling
procedure
for
securing
the
pump
while
installing
or
removing
fittings
are
as
follows:
1.
Use
two
soft
wood
blocks
in
a vise
to
protect
pump
from
vise
jaws.
2.
The
pump
square
mounting
flange
must
be
held
between
the
wood
blocks
at
right
angles
to
the
vise
jaws.
3.
Use
only
enough
vise
pressure
to
hold
pump
firmly.
CAUTION
Do
not
apply
vise
pressure
to
outside
diameter
or
overall
length
of
the
pump.
b.
Thread
lubricant,
if
required,
should
be
applied
sparingly
to
the
external
threads
of
the
fitting
only.
Use
a
powdered
moly
sulfide
or
graphite
in
dry
form
or
in
an
evaporating
vehicle;
or
employ
a silicone
spray.
INSTRUMENTS
Revised:
12/15/80
2K11