TM 5-4320-218-15
29
Idler gear
36
Cork washer
43
Plate
50 Pipe tee
30
Pipe plug
37
Hex nut
44
Engine support
51 Pipe nipple
38
Lockwasher
31
Gasket
45
Capscrew
52 Nut
39
Cap screw
32
Plate
46
Setscrew
53 Lockwasher
40
Lockwasher
33
Cap screw
47
Cork washer
54 Cover plate
41
Cap screw
34
Pipe plug
48
Oil sabre
55 Gasket
42
Lockwasher
49
Plug pipe
35
Short oil sabre
56 Stud,
Figure 28-Continued
(4) Remove the Allen-head setscrew that
(3) Examine the pump body and cover
was exposed when the slotted pipe
for cracks or breaks, and replace if
plug was removed.
defective.
(4) Test the fit of the idler gear on the
(5) Remove the nut (1, fig. 29) that se-
idler gear shaft. The gear should
cures the gear (2) to the oil-pump
turn freely but should have no per-
drive shaft (5). Place a suitable brass
ceptible wobble. If the gear wobbles,
rod or a similar punch against the
drive shaft, and carefully drive the
measure the gear bore and shaft
diameter. The diameter of the drive
s h a f t through the gear. The oil
shaft should be between 0.4993 and
pump assembly can then be removed
0.5002 inch. The diameter of the
by withdrawing it toward the center
shaft bore in the pump body should
of the crankcase. During removal,
be between 0.498 and 0,5017 inch.
the pump must be protected from
There should be a bore-to-shaft clear-
dropping into the crankcase.
ance of between 0.003 and 0.0027
c. Disassembly.
inch. The diameter of the driver gear
(1) Remove the cotter pin (9) and re-
stub shaft should be between 0,4993
move the spring (11) and check ball
and 0.5002 inch. The diameter of the
(10) from the cover (8).
bore in the driver gear must be be-
(2) Remove the screw (14) and lock-
tween 0.5003 and 0.5017 inch. Re-
washer (12); remove the screen (16)
place any part that is worn beyond the
from the cover.
limits specified above.
(3) Remove the screws (13 and 15), and
(5) Measure the diameter of the drive
remove the cover (8) and gasket (7)
shaft and the pump body. Replace
from the oil-pump body (3).
either item if worn beyond the limits
(4) Remove the Woodruff key (4) from
cited in d above.
the drive shaft (5), and push the
(.6) Check the keyway in the drive shaft
shaft and gear assembly out through
and drive gear. Repair any burred
the rear of the oil-pump body. Lift
keyways, or replace the shaft if nec-
the driven gear (18) off the stub
essary.
shaft (19).
(7) Examine the screen for enlarged op-
d. Cleaning, inspection, and repair.
enings or tears. Replace if necessary.
(1) Wash all of the parts in an approved
(8) Inspect the check ball and its seat in
cleaning solvent; dry thoroughly. Use
the cover for roughness. Replace the
a fiber brush to clean the screen.
cover or ball if necessary.
( 2 ) Examine the gears for cracked,
(9) Inspect the valve spring for pitting,
chipped, or worn teeth. Replace a de-
and replace if necessary.
fective gear. If the driver gear is to
( 1 0 ) Examine the machine screw for
be replaced, support the gear and
crossed threads. Replace if necessary.
drive out the pin that secures the gear
(11) Examine the bottom cover for cracks
to the shaft. Press the shaft from
or dents. Repair or replace the cover
the gear, press on a new gear, and in-
as necessary.
stall the pin.
