CHAP 5, SEC I
PRELIMINARY INSTRUCTIONS FOR
PAR 72
POWER TRAIN OVERHAUL
tightness of fit in the bore. If defects are
found, replace the bearing using the proper
replacer.
N o t e . Do not remove needle bear-
ings unless replacement is neces-
sary, since removal usually results
in destruction of the bearing.
d . Bushings, Bushing-type Bearings
- a n d T h r u s t W a s h e rs
(1) Inspect bushings and bushing-
type bearings for size, scoring and out-of-
roundness, burrs, sharp edges and evidence
of seizing. Minor scores, sharp edges and
s c r a t c h e s m a y b e r e m o v e d w i t h c r o c us
cloth.
O u t - o f - r o u n d , d e e p l y s c o r e d or
worn parts should be discarded.
Note.
D o n o t r e m o v e b u s h i n gs
b u s h i n g - t y p e b e a r i n g s u n l e s s
replacement is necessary, as re-
m o v a l u s u a l l y d a m a g e s t h e s e
parts.
(2) Remove bushings and bushing-
type bearings by using a puller or press
when possible.
Bushings in blind holes
may require removal by sawing or the use
of a narrow cape chisel.
C a u t i o n. If necessary to cut out a
bushing, do not damage the bore
into which it fits.
( 3 ) I n s p e c t t h r u s t w a s h e r s f o r
wear, distortion, scores and burrs.
C o r -
rect minor defects but replace parts that
are worn, scored or deformed.
e . Oil Seals, Preformed Packings
and Gaskets
( 1 ) I n s p e c t h o o k - t y p e s e a l r i n gs
f o r w e a r , d i s t o r t i o n a n d b r o k e n h o o k s.
R e p l a c e d e f e c t i v e s e a l r i n g s . I n s t a l l a
new hook-type seal ring if the ring shows
any wear on the outside circumference, or
if there is excessive side wear. The sides
of the seal ring must be smooth within
0.005-inch maximum side wear. The sides
o f t h e s h a f t g r o o v e ( o r t h e b o r e ) i n to
which the seal ring fits should be smooth
w i t h i n 5 0 m i c r o i n c h e s e q u i v a l e n t a nd
square with the axis of rotation within
0 .0 0 2 - i n c h . I f t h e s i d e s o f t h e g r o o v es
have to be reworked, install a new seal
ring.
( 2 ) I n s p e ct
m e t a l - e n c a s e d l i p-
type seals for cracks, wear, cuts and brit-
tleness. Inspect springs and seal shells.
Replace any seals found defective.
N o t e. Any time a metal-encased
lip-type seal is removed, it must
be replaced with a new seal.
f . G e a r s
(1) Inspect gears for burrs, wear,
pitting and broken teeth at tooth contact
areas.
( 2 ) I n s p e c t b o r e s o f p l a n e t a r y
pinions for wear and pitting of bearing
contact areas.
( 3 ) R e m o v e b u r r s u s i n g a s o ft
h o n i n g s t o n e . R e p l a c e g e a r s t h a t a re
excessively worn or pitted.
g . Splined Parts
( 1 ) I n s p e ct
s p l i n e d p a r ts
f o r
twisted or broken splines, burrs and ex-
cessive wear.
( 2 ) R e m o v e b u r r s u s i n g a s o f t
honing stone. Replace parts which have
twisted or broken splines and excessive
wear.
h . C l u t ch P l a t es
( 1 ) I n s p e c t f r i c t i o n - f a c e d s t e e l
p l a t e s f o r b u r r s , e m b e d d e d m e t a l p a r-
t i c l e s , s e v e r e l y p i t t e d f a c e s , e x c e s s i ve
w e a r , c r a c k s , d i s t o r t i o n a n d d a m a g ed
splined teeth. Remove burrs using a soft
honing stone. Replace plates which have
other defects.
(2) Inspect steel plates for burrs,
scoring, excessive wear, distortion, em-
bedded metal, galling, cracks, breaks and
damaged spline teeth. Remove burrs and
minor surface irregularities using a soft
honing stone. Replace plates which have
other defects.
76 Change 2
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