Chevrolet 30 Series 1967 Service Manual page 394

CLUTCHES AND TRANSMISSIONS 7-8
General Description.............................. ..
Maintenance and Adjustments..................
Preliminary In s p e c tio n .....................
Clutch Retracting Spring Replacement
Diaphragm Clutch Adjustment
PRELIMINARY INSPECTION
There are many things which affect good clutch opera­
tion. Therefore, it is necessary, before performing any
m ajor clutch operations, to make a preliminary inspec­
tion to determine whether or not the trouble is actually in
the clutch.
1. Check the clutch pedal and make sure that the pedal
has at least 1/8" free travel (Hydraulic Clutch Con­
trols), or 3 /4 "-1 " (Mechanical Linkage).
2. Check the clutch pedal bushing for wear and for
sticking on the shaft or loose mountings.
3. Lubricate the pedal linkage.
4. Tighten all front and rear engine mounting bolts.
Should the mountings be oil soaked, it will be neces­
sary to replace them.
CLUTCH RETRACTING SPRING REPLACEMENT
A rattle in the clutch assembly at idling speeds with the
clutch released or failure of the clutch to release prop­
erly may be caused by insufficient tention on the pressure
plate retracting springs. These troubles can easily be
Fig . 16 - Checking Pressure Plate Lift with D ial Indicator
DIAPHRAGM SPRING CLUTCH
Page
7-8
7-8
7-8
7-8
................................. 7-E
GENERAL DESCRIPTION
The clutch, used on 230 and 250 cubic inch
engine trucks, is a single plate dry disc type consisting of
two basic assem blies, the driven disc and facing assem­
bly and the cover, pressure plate and diaphragm and dia­
phragm spring assembly.
MAINTENANCE AND ADJUSTMENTS
INDEX
Service O perations............
Clutch Assembly . . . .
Removal from Vehicle
Installation to Vehicle
- Cylinder
6
Fig. 17 - G auging Shim Requirement
checked by replacing the springs, as follows:
1. Remove the clutch housing underpan.
2. Hand crank the engine until one retracting spring at­
taching bolt is at the bottom. Remove the bolt and
retracting spring and install a new spring.
3. Replace the other retracting springs in the same
manner.
4. Replace clutch housing underpan.
DIAPHRAGM CLUTCH ADJUSTMENT
If clutch fails to release:
1. Check pedal for proper travel and linkage for loose­
ness, adjustments, etc.
2. Check clutch retracting springs for proper retention
of pressure plate to diaphragm spring, replace if
necessary. This can be done without removing clutch
from vehicle.
3. If Steps 1 and 2 do not cure trouble, check pressure
plate lift with dial indicator (fig. 16) as follows:
a. With proper linkage adjustment (and lash), zero
indicator with clutch fully engaged (pedal up).
b. Measure pressure plate lift at 3 strap bolt posi­
tions with full pedal travel.
NOTE: Use 5/8" thick board in place of floor
mat to give a positive stop.
All three readings should be within .010" and
within total lift readings. If more than .010"
Page
i 7~9
7-9
7-9
7-9
CHEVROLET TRUCK SERVICE MANUAL