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CLUTCH
6 - 3
ing. To avoid w a r p i n g the cover, the bolts must t i g h t -
ened alternately (diagonal pattern) and evenly (2-3
threads at a time) to specified torque.
Clutch Housing Misalignment And Runout
C l u t c h housing alignment is i m p o r t a n t t o proper
operation. The housing bore m a i n t a i n s a l i g n m e n t be-
tween t h e crankshaft and transmission i n p u t shaft.
Misalignment can cause noise, incomplete clutch r e -
lease and chatter; I t can also result i n premature
wear o f the pilot bearing, cover release fingers and
clutch disc. I n severe cases, m i s a l i g n m e n t can also
cause premature wear of t h e transmission i n p u t
shaft and bearing.
Housing face m i s a l i g n m e n t is generally caused b y
incorrect seating on the engine or transmission, loose
housing bolts, missing a l i g n m e n t dowels or housing
damage. Infrequently, m i s a l i g n m e n t m a y also be
caused by housing m o u n t i n g surfaces t h a t are n o t
parallel.
I f housing m i s a l i g n m e n t is suspected, housing bore
and face r u n o u t can be checked w i t h a d i a l indicator
as described i n the following two procedures:
MEASURING
CLUTCH
HOUSING
BORE
RUNOUT
(1) Remove the clutch housing and s t r u t .
(2) Remove the clutch cover and disc.
(3) Replace one of the flywheel bolts w i t h a 7/16-20
by t e n inch (25.4 cm) long threaded rod (Fig. 1). T h e
rod w i l l be used to m o u n t t h e d i a l indicator.
(4) Remove the release fork f r o m the clutch hous-
ing.
(5) Reinstall the clutch housing. T i g h t e n the hous-
i n g bolts nearest the alignment dowels first.
(6) M o u n t t h e d i a l indicator on t h e threaded r o d
and position the indicator plunger on t h e surface o f
the clutch housing bore (Fig. 2).
(7)
Rotate
t h e crankshaft
u n t i l
t h e indicator
plunger is a t the top center o f the- housing bore. Zero
the indicator at t h i s point.
(8) Rotate the crankshaft and record t h e indicator
readings a t eight points (45 degrees apart) around
the bore (Fig. 3). Repeat the measurement a t least
twice for accuracy.
(9) Subtract each reading f r o m the one 180 degrees
opposite to determine magnitude a n d direction o f
runout. Refer to Figure 3 and following example.
Bore r u n o u t example:
.000 -(-.007) = .007 i n c h
+ .002 - (-.010) = .012 inch
+ .004 - (-.005) = .009 i n c h
-.001 - ( + .001) = -.002 i n c h ( = .002 inch)
I n the above example, the largest difference is .012
i n c h and is called the t o t a l indicator reading (TIR).
This means t h a t the housing bore is offset from the
crankshaft centerline b y .006 i n c h (which is 1/2 of
.012 inch).
The acceptable m a x i m u m T I R for the housing bore
is .010 i n c h . However, i f the T I R is more t h a n .010
(as i n t h e example), bore r u n o u t w o u l d have t o be
corrected w i t h offset dowels. Offset dowels are avail-
able i n .007, .014 and .021 i n c h sizes for t h i s purpose
(Fig. 4).
I f housing bore r u n o u t exceeds .010 TIR, refer to
Correcting Housing Bore R u n o u t for offset dowel i n -
stallation.
CORRECTING
CLUTCH
HOUSING
BORE
RUNOUT
The d i a l indicator reads positive w h e n the plunger
moves i n w a r d (toward indicator) and negative when
i t moves o u t w a r d (away f r o m indicator). A s a result,
the lowest or most negative reading determines t h e
direction o f housing bore offset (runout).
I n t h e sample readings shown i n F i g u r e 3 and i n
step (7) above, the bore is offset t o w a r d the .010 inch
reading. To correct t h i s , remove t h e housing and
o r i g i n a l dowels. T h e n i n s t a l l the new offset dowels i n
the direction needed to center t h e bore w i t h t h e
crankshaft centerline.
I n t h e example, T I R was .012 inch. T h e dowels
needed t o correct offset w o u l d be P/N 1736347 w i t h
an offset of .007 i n c h (Fig. 4).
I n s t a l l the dowels w i t h the slotted side facing out
so they can be t u r n e d w i t h a screwdriver. Then i n -
s t a l l t h e housing, r e m o u n t t h e d i a l indicator a n d
check bore r u n o u t again. Rotate the dowels u n t i l the
T I R is less t h a n .010 i n c h i f necessary.
I f a T I R of .053 i n c h or greater is encountered, i t
may be necessary to replace the clutch housing.
7/16- 20 THREAD
NUT
10 INCHES LONG
J9006-25
Fig. 1 Dial Indicator Mounting Stud Or Rod
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