Vacuum Pump Removal - Piper PA-24 Comanche Service Manual

PIPER COMANCHE SERVice MANUAL
NOlE
Do not attempt adjusancnt of
this valwc
wilh the
enpae
ill opcnaoft.
b. Scart the
eftline. Aim
aUowinB
time
for WUIIMIp. run the fllliac at medium
RPM.
c.
With the
eDginc runnial
at medium RPM. the suClion
pup
should
iDdicate
between 4.2 and 4.7
inches of mercury. Units with a central. air filter
system should indicate between 4.8
&Del 5.1
inches of
mercury. If the vacuum
rcadinJ
faa. to fall within
tbia,...
shut dowa die CJIIine UId adjust the rqulator
yaJve. Move the valve
adjustmCllt
ICTC'W'
dockwile
to
iIlc:reuc the prawn and couaeaclockwiJe to decreuc
the preate. Scart
the ftlJine ud rqteat the chftk.
d.
After the system preate hal beal
adjured
to
the recommaaded tmiDp.
ren,htcn
the lockinl
nut or replace the protettive cap.
11·14. Vacuum Pump. The vacuum pump used on the Comanche is the rotary vane. POSItive
displacement type. The unit consists essentially of an aluminum housing containing a tempered sleevein
which an offset rotor. with moving blades. is incorporated. This assembly is driven by a coupling mated
to the engine driven gear assembly. The pump is mounted on the accessory section of the engine.
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11-15. Vacuum Pump RClDonL The
naaUDl
pump is mIIO'Nd by eIle
foUowiat
procedure:
L
Remowe the
top
ponion of
the
encia. cowIint.
b. LOOICft the
twO
hose
damPI and mnove the nro bola from the
V&al1111l
pump fittinp. Identify
the hoses to aid in rcinsullacion.
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c.
Remove the four
rctainin,
nuts,
lock wuben Ulli p&IiD
._en.
d.
Remove the vacuum pump.
NOTE
Before
iImallaaoa. of 6aiDp
on
pump.
check for
cneruJ
damqre. A
pump that hu been
dIm.pd
or dropped Ibould not be iDlulled. WbeD
a vise
is \lied to secure JNIDp wbi1c
inR",in, fit'linp. lUiable
cauaon
must be exercised
to
avcrid
pump
climap. The
square
IIlCllUlciDI
flanF
must be bdd bcnrem SOft wood blodu uul OIl1y at riPt aapes
to
the
vise iaWl. Usc oaly eDoutb
vise
preaure
to
bold
pump
firmly. DO NOT
apply
vile
preuure to ouaMlc
diam.-r
or
owraI1 lcapb.
The pora of
the AIRBORNE dry air pump bve
bea crated
with a dry
fUm
lllbrica.at
md
me
AIRBORNE fia:iDp arc cadmium paced
mus
eliminaciD, any need
for
dlIead 11lbrica.aa. If
&
duad
lubric:aDt is
tequircd, use a
powdered
moly
sulfide
or
IftPbitc
ill dry form or ill an
evaporaciD. vebide; or employ a siliCODe spray. Apply spuiqly
to
enenW
tbrcadl of fittiDp only. DO NOT
u. pipe cape. duad dope.
bydrocarbon oil or JftUC. u
mae
can contaminate pump
uul
caux
malfwu:aoft. With pump properly secured
ill vile. iDleR
fiaiDp
in
pom
and hand tilh1leD fU'rllly. Sext,
IlSiDJ
a wrench. upumClch 6ttiD1 from
one-baJf to two
tunIS
addiaonai.
INSTRUMENTS
REVISED:
4/10/81
3
F22
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