GMC 4000 Series Service Manual page 464

CLUTCH PEDAL A N D BUSHING
ASSEMBLY REPLACEMENT
(ALL "L" MODELS)
REMOVAL (Refer to Fig. 8)
1. Tilt cab forward.
IMPORTANT: Make sure cab safety catch
at right front pivot mounting is securely engaged.
2. Disconnect pedal return spring (8).
3. Separate pedal upper section (10) from
lower section (11) after removing attaching bolt
(9).
4. Loosen bolt (5) which clamps pedal shaft
lever (7) to pedal shaft. Slide pedal and shaft
assembly (11) from cab s ill and from spacer (6),
and pedal shaft lever (7).
5. Through sm all access hole at base of cab
sill, remove the pedal shaft lubrication fitting
(15).
6. Remove two hex-head screw s (13) which
attach the flange of pedal shaft sleeve and bushing
assembly (14) to the cab sill.
7. Using a pointed tool under flange of sleeve,
pry shaft sleeve and bushing assembly (14) from
cab sill.
INSTALLATION (Refer to Fig. 8)
1. Temporarily install pedal shaft back into
sleeve and bushing assem bly (14) and check for
excessive wear. If necessary, p ress worn bush­
ings from sleeve and p ress new bushings in their
place.
2. Making sure that the lubrication fitting
hole is at the bottom, insert sleeve and bushing
assem bly (14) into cab s ill and secure with two
screw s (13).
3. Install lubrication fitting (15) into tapped
hole at bottom of sleeve.
4. Slide pedal and shaft assembly (11) through
sleeve assembly (14), through special spacer
(6), and into the partly serrated hole of the pedal
shaft lever (7). Make sure shaft lever is posi­
tioned as shown in figure 8.
5. Remove all shaft end play, then clamp
pedal shaft lever (7) to end of shaft by tightening
lever clamp bolt (5) and nut.
6. Attach pedal upper section (10) to pedal
lower section (11) with bolt (9), nut, and washer.
IMPORTANT: Make sure that bolt is in­
serted in direction shown.
7. Referring to figure 8, install clutch pedal
return spring (8).
IMPORTANT: Exercise
stalling spring.
8. Make sure that pedal stop (12) is in good
condition and is located on pedal shaft as shown.
G M C S E R V I C E M A N U A L
is used on all " L" models with mechanical trans­
m ission and hydraulic brakes. The unit consists
of two cylinders with an integral reservoir. The
right cylinder serves as the brake master cylin­
der, and the left cylinder serves as the clutch
master cylinder.
MAINTENANCE (ALL TYPES)
cylinders are designed to vent the fluid reservoir
without permitting loss of fluid. Bypass port be­
tween cylinder bore and reservoir and vent hole
in filler cap must be kept open to assure proper
clutch control. An obstructed bypass port will
prevent return of fluid to reservoir, preventing
full engagement of clutch. Bypass ports may be
obstructed by one of the following causes:
der and disassem ble and clean all parts.
wrong fluid — overhaul master cylinder, drain
and flush entire clutch control system , and refill
with proper fluid.
caution when in­
return of piston - - free up and lubricate pedal.
push rod.
CLUTCH CONTROLS
Figure 13— Clutch Master Cylinder
CLUTCH MASTER CLYINDER
A double-barrel master cylinder (see fig. 13)
Filler cap or cover on all clutch master
1. Cogged with dirt - - remove master cylin­
2. Swollen primary cup due to the use of
3. Pedal binding on shaft, preventing full
4. Improper push rod adjustment — adjust
Sec. 7D
Page 453