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ENGINE FUEL AND EXHAUST SYSTEMS
FUEL AND VACUUM PUMP
3-21
3-19 FUEL AND VACUUM PUMP
REPAIRS
If only the vacuum section of the pump
requires replacement of the diaphragm or
valves, the procedures given in subparagraphs
a,
C,
and
e,
should be followed. If the fuel
section of pump requires replacement of the
diaphragm,
however,
the complete procedure
given in subparagraphs
a
through
e
must be
followed
.
The fuel diaphragm is sealed around the pull
rod with a tight fitting oil seal which is staked
into the pump body. Tilting of the diaphragm
to unhook pull rod from the fuel link will
damage this oil seal. The safest method to follow
is to first remove the rocker arm and link so
that diaphragm pull rod can be pulled straight
out without damage to the seal.
The vacuum diaphragm should be removed
bef
ore
the fu
el
diaphragm andd installed after
the fuel diaphragm because the fuel diaphragm
and link cannot be correctly assembled with
the vacuum diaphragm connected to the vaccum
links.
a. Removal of Vacuum Diaphragm
and Valves
1. Plug all openings and thoroughly wash
outside of the unit with cleaning solvent and
blow off with air hose to remove all dirt and
grease.
2. Mark edg
es
of vacuum cover and pump
body with edge of a file, so that cover may
be.
reinstalled in its original position on body.
3. Remove only two cover screws from oppo-
site
sides of the cover, and substitute for them
two
No.
10-32 x
I
1j2"
fillister
head screws. Turn
the two long screws all
the
way
down,
and
then remove the balance of the short screws.
Alternately back off the two long screws, a few
turns at a time, until the force of the heavy
vacuum diaphragm spring is no longer effective.
If cover and body stick together, rap cover
with screwdriver handle after backing off long
screws a few turns; do not pry between the
flanges.
Remov e long screws,
vacuum cover
assembl
y ,
diaph
ragm s
pr i ng
an
d spring
retainer. See figure
3-25.
4. Remove cover plate and gasket, retainer
and
screen,
valve retainer and valves from
vacuum cover.
5. Hold pump with vacuum diaphragm down
while pushing upward on diaphragm to unhook
diaphragm pull rod from the vacuum links.
6. Remove oil seal retainers, seal, and spring
from diaphragm pull rod. See figure
3-26.
7. If fuel section of pump is to be repaired
also, proceed with subparagraph
b ;
otherwise,
inspect parts removed (subpar.
c)
and re-
assemble vacuum section with necessary new
parts
(subpar.
e) .
b. Removal of Fuel Diaphragm and Valves
1. Mark edges of fuel cover and pump body
with edge of a file, so that cover may be rein-
stalled in its original position on body.
2.
Remove fuel cover screws and separate
the cover from pump body by rapping
with
screwdriver handle; do not pry between flanges.
3. Remove bowl and gasket,
screen,
valve
retainer and valves from fuel cover.
See
fig-
ure
3-26.
4. File riveted end of rocker arm pin flush
with steel washer, or cut off end with 3;8" drill,
then drive out rocker arm pin with a drift
punch.
Wiggle rocker arm until link unhooks
from fu
el
diaphragm, then remove ro
cker
arm
and link assembly, and rocker arm spring.
5. Remove fuel diaphragm from body by
pulling straight
out.
CAUTION: Do not tilt
ex
cessively or stak ed-in oil seal in pump body
will
be
dam
aged.
Remove diaphragm spring
and spring retainer.
6. Remo
ve
bushing from rocker arm to dis-
assemble
rocker arm, t
wo
vacuum
links,
one
fuel
link,
link
spacer,
and link
washers
(there
may be
one
or two link washers). See fig-
ure 3-26.
c. Cleaning and Inspection of Pump Parts
Replacement parts are available in three
different kits, as follows:
Vacuum Pump Diaphragm Kit
Fuel Pump Diaphragm Kit
Overhaul
Kit
Each diaphragm kit contain the proper
diaphragm, valves, springs, and gaskets to
service the indicated section of the pump. A
separate rocker arm pin is required with the
fuel pump diaphragm kit. The overhaul kit
conta ins all parts in both diaphragm kits plus
links and other p
a rts
subj
e ct
to w
ear
or
deterioration.
The kit t
o use will be determined
by
the
corrections required, or by inspection of dis-
assembled parts as follows:
1. Clean and rinse all metal parts in solvent.
Blowout all passages WIth air hose.
2. Inspect pump body, fuel, and vacuum
covers for cracks, breakage, and distorted
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