Resistance Check (Plunger Type Pump) - Piper Comanche PA-24 Service Manual

PIPER COMANCHE SERVICE MANUAL
2.
La .. Plunger Pump. (Refer to F ...... 8-16.)
•. DetaCh pump from the &irenit ond nomove the bottOm eover
(I).
psket
(2)
&nd filter
(4).
b.
Remove the maiDer spring
(5)
from the plunger tube (11) uRns thin nose pliers to sprall ond
nomove ends of retainer from tube. Then remove washer (6). "0" ring seal
(7).
cup nlve (8). plunger sprins
(9) &nd plunser
(10)
from tube (11).
c.
Wash partS in cleaning solvent ond blowout with &ir pressure. If plu"ler does not wuh clean
or if there .... &Dy roulh spoa ,endy <leon surf .. e with aoc:us cloth. Slosh the pump usembly in cleaninJ
solvent. Swob the inside of the tube with. cloth wnpped &round. Rick ODd blowout with &ir prasurc.
d. To rcuscmble the pump. insert the plu ..... assembly
(10)
in me tubc with me buffer sprins
end first. Check fit by slowly r&ising ond lowering the plunler in the tube. It should move freely without
ony tendency to stick. If • click cannot be heard. the interruptct uoembly is not functioning properly in
which cue the pump should be replaced.
•. To complete the uscmbly. install the plunser spring (9). cup valve (8). "0" rins seal (7) &nd
wuher (6). Compr ... sprins (9) &nd usemble reuinet (5) with ends of retainet in side holes of tubc (II).
Reinsull filter. COVet , .. k.t. m .. net &nd covet. Safety &nd
install
on &irenit. Check for fuelle&k ....
8-27. Resistance Check (Plun ... Type Pump). To check the resist&nce of the pump. cOMecr &n ohmmeter
to the lcod wire of the pump &nd the pump body. A read ins of 4.87 to 6.4 ohms for a 12 volt pump should
be obwned.
8-28.
Scrvicm,
Of
Fuel Pumps
Bendix Model
Nos. 480 518-1,480 528" 480
,no
1. Dcscn?tion and Gonen! Inform.tion
a. These .... v&ne type positive displacement pumps. driven by 12 volt DC moto". Each model
has
I
built-in pressure relief valve which functions to bypua fuel. via Internal Pas5afn. to the inlet port. The
motor dnves the pump through a rubber coupli,,,. A "live" shoft seal
IS
in the pump section of th •
.... mbly.
b Field semcins conlisa of rcplaClng rhe foUowins partS .. ""luir.d, Cover G .. ket (I l). Sh.it
Seal (12). Coupling (2). Motor G .. ket (II) &nd Motor (1). Refer to PortS Catalog for r.placement part
numben.
c.
If a pump is removed beca.use of fucllc:lkq:c.
dry the outside of the pump Ind run [he pump
on the bench
With
test fluid to determine if leakage
is
from the cover gasket or the shaft seal.
Z. Cover G .. k.t Repl.cement. (Ref.r to Figure 8-17.)
a.. .\tark the position of the c:over with a. scribe mark. Remove the ei&:ht cover screws (10) and the
c:over (9). The spring (8) &nd pressure plate (7) are now loose and may be set uide. There is no need to
remove any vanes (6), use cue to assure that none arc loSt. Remove the cover gasket
(13)
and all traces of
this gasket from sealin, surfaces on the cover &nd housil1!l usembly (l).
b Reassembl. the pump using • new Cover Gasket (13). The g .. ket should drop ov.r 'he
hOUSIng Insert (4).
~ote
that the spring (8) and pre5Sure plate (7) must be located
tn
their respective
counterborcs in the cover (9) as the cover is pulled down by the screws (10). Be sure the cover is Inswled in
its original ?ositlon. (With the cover Installed correctly. the caSt word "Bendix" on the cover will be on a
dIagonal with the
"s"
neareSt the outlet). Torque the cover screws (10) In oppoSIte
PaL"
to between 25 and
lS in. Ibs.
3 .'Aotor Replacement.
a. Remove the
tWO
motor nu
ts
(1 .. ), the motor ( 1). the motor ,uket (11) and the coupling (2).
If there IS
1
felt cylinder in the coupling end of the nOUSlng usembly. remove this felt cylinder and discard
It.
2JIO
FUel SYSTEM
ISSUED: 8/18n2