Late Plunger Pump; Plunger Type Pump Resistance Check; Servicing Of Fuel Pumps Bendix Model - Piper PA-24 Comanche Service Manual

PIPER COMANCHE SERVICE MANUAL
2. ute Plunger Pump. (Refer to Figure 8·16.)
a.
Detach pump
from
the &ireratt and remove the bonom
cover
(1).
psket
CZ) and
ftlter
(4).
b. Remove the retainer spring
(5)
ftom the plunpr tube
(11) usahl
thift nose plien to spread and
remove ends of retainer from Nbe. Then remove washer
(6). "0"
nn,
sea!
(1).
ClIp valve
(8).
pluftler sprinl
(9)
and plunger
(l0)
from Nbc
(11).
c. Wash pans in cleanin, solvent and blow
OUt
with
air
praIUI'C.
If pluftlft does not wash clan
or if there are any roulh spoa lendy clean surface with croaas cloth. Slosh the pump UlCftbly in ciCUling
solvent. Swab the inside of the Nbe with
&
doth wrapped around a stick and blowout with air preslllre.
d.
To reuscmble the pump. iNert the plunF wembly
(10)
in the tube with the buffer spring
end first. Check fit by slowly raisin, and -lowerinr the plunger in the Nbc. It should move freely without
any tendency to stick. If a dick cannot be heard. the intcmapter Ulelftbly is not functionin. properly in
which case the pump should be replaceci.
e. To complete the assembly. insull the plunser
spnn,
(9).
cup valve (8). "0" ring SCI.!
(7)
and
wuher
(6),
Compress spring
(9)
&nd assemble retainer
(5)
trith ends of mainer in side holes of rube
(11),
Reinstall filter. cover guket. m.,ner and cover. Safety and insull on aitctaft. Check for fuelleakaae.
8-27.
~nce
Check
(ptunpr
Type Pump). To chedc the resistance of the pump. connect an ohmmeter
to the lead wire of the pump and the pump body. A
readm,
of 4.87 to 6.4 ohms for a 12 volt pump should
be obtained.
8-28.
Scrvicint
Of Fuel Pumps Bendix Modd
NOI.
410 51"1,480 528 Ir 410 533.
1.
Descri?oon and Generallnfonnation.
t.
These arc vane tYpe positive displacement pumps. driven by 12 volt DC motors. Each model
has a built-in pressure relief valve which functions to byp. . fuel. via intcm&1 passqa. to the inlet
POft.
The
motor drives the pump through a rubber coupling. A
"live" shaft seal is in the pump section of the
asst:mbly.
b. Field servicing consists of replacing the followi.. partS as
reqUired:
Cover Gasket,(U}, Shaft
Seal (12),
Coupling
(2).
Motor Gasket (11) and Motor
(1).
Refer to
Parts
Catalol for replacement part
numbers.
c. If a pump is removed because of fuelleakaJe. dry the ouuide of the pump and run the pump
on the bench with test fluid to determine if leakap is from the cover ,asker or the shaft
seal.
2. Cover Guket Replacement. (Refer to Fil\lre 8·17.)
a. .\tark the position of the cover with a scribe
muk.
Remove the eilht cover screws
(10)
and the
cover (9). The spnn, (8) and pRSSUre plate (7) arc now loose and may be set asidc. There is no need to
remove any
vanes
(6),
use care to UI\lrc that nOlle are lost. Remove the Covet piker
(13)
alld aJl mca of
this gasket from sealing surfaces on the cover and housm, assembly
(3).
b. Reassemblc the pump using a new Cover Gasket
(13).
The ,asket should drop over the
housing insert
(4).
Sote that the sprins
(8)
and pressure plate
(7)
must be located in their respective
counterbores in the cover (9) as the cover is pulled down by the
screws
(10).
Be sure the cover
is
installed in
its original position. (With the cover installed correctly, the
cast
word "Bendix"
011
the cover will be on a
dilJonal with the
"8"
nearest the cutlet). Torque the cover screws
(10)
in opposite paL" to betWecn
2$
and
35 in. lbs.
3.
.\1otor Replacement.
I.
Remove the cwo motor nutS
(l4),
the motor
(1),
the motor gasket
(11)
and the coupling
(2).
If there is
a
felt cylinder in the coupling end of the housinl assembly
I
remove this,felt cylinder and discard
it.
FUel SYSTeM
ISSUED: 8/18nZ
2JI0
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