Chevrolet 10 Series 1968, Service Manual

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CLUTCHES AND TRANSMISSIONS 7-11
GENERAL DESCRIPTION
The 427 cu. in. engine for 1968 is equipped with a 2
plate, dry disc type clutch consisting of three basic as­
semblies: The cover and rear pressure plate assembly,
front pressure plate assembly and dual driven disc as­
sembly. The dual driven disc assemblies are splined to
the transmission main drive gear (clutch gear) shaft. The
front pressure plate, located between the driven discs,
has
2 friction surfaces and is coupled to both the rear
pressure plate and cover through pairs of steel drive
straps bolted at each of its 4 driving bosses.
The cover is bolted to the engine flywheel. Coil type
pressure springs, located between the cover and rear
pressure plate, provide positive engagement between the
cover, the pressure plates, driven disc assemblies and
flywheel.
No adjustment for wear is provided in the clutch itself.
An individual adjustment is provided for locating each
lever. In manufacturing this lever adjusting nut is locked
in place and should never be disturbed unless the clutch
is disassembled for overhaul.
SERVICE OPERATIONS
Removal From Vehicle
1. Refer to applicable procedure in Transmission Sec­
tion 7, and remove transmission. Release bearing
and actuating mechanism are assembled in housing at
front of transmission and may be inspected without
disassembly.
2. Look for "X " mark stamped on pressure plates,
cover and flywheel. If "X " is not stamped on all 4
pieces, punch mark them (with prick punch) in a line
at one location for alignment purposes during
installation.
3. Install aligning tool (J-21169) or an old transmission
main drive gear, through hubs of driven discs into
pilot bearing, and place a wood or metal spacer (ap­
proximately 1” x 1" x 3/8” thick) between each re­
lease lever and clutch cover (fig. 19) to facilitate
removal and installation.
4. Rotate the flywheel (if necessary) to locate one cover
mounting bolt at top, then loosen all 4 cover mounting
bolts alternately and evenly until pressure is re­
leased from discs.
5. Remove top bolt and install alignment stud (part of
Tool J -21169) in its place.
6 . Remove 3 remaining bolts (allowing clutch assembly
F ig . 20 —C lu tch Release Finger Adjustment
to hang from stud), then slide clutch assembly from
stud to remove from vehicle.
F ig . 19—C lu tch Removal or Installation
1. Place alignment tool (stud section) in upper clutch
mounting bolt hole.
2. Install alignment tool (arbor section) through rear
driven plate splines and install front driven plate
over tool with hub section of plate toward flywheel.
3. Lift complete clutch assembly (with one hole held to
top) and slide upper bolt hole over alignment stud in
flywheel, then work clutch discs as needed to slide
arbor pilot into pilot bearing.
4. Install three bolts loosely, then remove alignment
stud and install last bolt loosely.
5. Thread alignment stud in arbor (to act as arbor
handle), make sure discs are in good alignment, then
tighten the cover attaching bolts a turn or two at a
time in rotation to prevent distortion.
6
. Adjust clutch fingers (if cover was disassembled) by
placing a straight-edge over the alignment arbor end
and fingers, and adjust fingers level as shown in
Figure 20.
7. After adjustment is completed, stake the adjusting
nuts to eye bolts to lock the adjustment, then remove
arbor and install transmission as outlined in Sec­
tion 7.
8
. Adjust clutch pedal linkage as previously outlined.
Installation to Vehicle
CHEVROLET TRUCK SERVICE MANUAL