Buick LeSabre 1965 Service Manual page 139

CLUTCH, S-M TRANSMISSIONS
45000 CLUTCH 4 - 3
gear and is keyed to the gear by
ten splines. The front end of the
main drive gear is piloted by a
bushing pressed into a recess in
the rear end of the engine crank-
shaft. See Figure 4-1.
The outer area of the driven plate
is divided into segments which
are formed in low waves to pro-
vide springs between the plate
facings and thereby cushion en-
gagement of the clutch. A molded
facing, grooved to give release, is
riveted to each side of every seg-
ment of the plate. When the clutch
is fully released, the waved seg-
ments cause the facings to spread
a p p r o x i m a t e l y .045" and the
movement of pressure plate pro-
vides an additional clearance of
approximately .030" to assure
full release of driven plate. See
Figure 4-2.
The driven p l a t e assembly is
designed to prevent torsional
periods of the engine from being
transmitted to the transmission
gears and causing rattle. This is
accomplished by driving the plate
hub through torsional coil springs
and providing frictional dampen-
ing by means of friction between
disc and the nuts.
c. Clutch Linkage
The clutch pedal is the suspended
type and pivots on a shaft which
extends thru a bracket bolted to
the cowl. The pedal arm returns
against a rubber bumper. See
Figure 4-3.
The clutch pedal rod extends from
the clutch pedal arm assembly
through the floor pan to connect
with the frame side of the equal-
izer. The equalizer pivots be-
tween a ball stud located at the
frame and a ball stud located
on a bracket l o c a t e d on the
transmission.
A rod threaded at one end is
attached to the clutch fork op-
erating rod assembly which is
attached to the engine side of the
clutch equalizer and the other end
is attached to the clutch fork.
The threaded end of the rod is
provided for clutch adjustment.
See Figure 4-3. Movement of the
equalizer assembly is thus trans-
mitted to the clutch fork. Pedal
return is provided by a spring
between the clutch rod assembly
and a bracket mounted on the
flywheel housing. See Figure 4-3.
4 - 3 CLUTCH ADJUSTMENT
Pedal lash (free pedal) must be
adjusted occasionally to compen-
sate for normal wear of clutch
facings. As the driven plate wears
thinner, pedal lash decreases.
It is very important to maintain
pedal lash at all times. Insuf-
ficient pedal lash will cause the
throw-out bearing to ride against
the diaphragm spring tangs con-
stantly, resulting in abnormal
wear of these parts. It may also
cause clutch slippage and abnor-
mal wear of the driven plate, fly-
wheel, and pressure plate if
pressure on the spring tangs is
enough to prevent positive en-
gagement of the clutch.
Check pedal lash (free pedal) by
pushing on the pedal pad with the
hand. Pedal lash should be ap-
proximately 5/8" to 7/8" meas-
ured at the pedal pad. (See
Figure 4-3).
Adjust pedal lash as follows:
1. Check pedal at full release
position, making sure it contacts
rubber stop.
2. Make certain clutch fork is
touching fingers on p r e s s u r e
plate.
3. Adjust clutch release rod so
clevis pin will just assemble into
clutch fork.
4. Lengthen release rod 3 full
turns. Re-install retainer and pin.
4 - 4 REMOVAL,
LUBRICATION
INSPECTION AND
INSTALLATION
OF CLUTCH
a. Removal from Vehicle
1. Remove transmission as out-
lined in paragraph 4-15.
2. Remove clutch throw-out bear-
ing from the fork.
3. Remove clutch fork return
spring. Disconnect clutch fork
release rod.
4. Remove flywheel housing.
5. Disconnect clutch fork from
ball stud by forcing it toward the
center of the vehicle.
6. Mark clutch cover and fly-
wheel with a center punch so that
cover can be reinstalled in the
s a m e position on flywheel in
order to preserve engine balance.
7. Loosen the clutch attaching
bolts one turn at a time until
diaphragm spring is released.
8. Support pressure plate and
cover assembly while removing
last bolts, then remove pressure
plate, then the driven plate.
NOTE: Use extreme care to keep
clutch driven plate CLEAN.
9. If it becomes necessary to dis-
assemble pressure plate, proceed
as follows:
a. Remove three drive-strap to
pressure plate bolts and retract-
ing springs and remove pressure
plate from clutch cover.
NOTE: When disassembling, note
position of grooves on edge of
pressure plate and cover. These
marks must be aligned in assem-
bly to maintain balance.
b. The clutch diaphragm spring
and two pivet rings are riveted to
the clutch cover. Spring, rings
and cover should be inspected for
excessive wear or damage, and if
there is a defect, it is necessary