GMC 4000 Series Service Manual page 241

Sec. 5B
Page 234
AIR BRAKES
1 Lock Ring
2 Spacer
3 Slack Adjuster
4 Camshaft Seal
5 Camshaft Bushing
bracket is equipped with two bushings and a lubri­
cation fitting. Space between bushings acts as a
lubricant reservoir. Lubricant should be applied
sparingly at intervals specified in LUBRICATION
(SEC. 0) in this manual.
CAUTION: Do not overlubricate camshaft, as
excess lubricant will be forced into brake drums.
Slack adjuster, mounted on splined end of
camshaft, is held in place by a lock ring. A spacer
"S" cam brake assem blies are used on rear
axle of all tilt cab models and all 5500 Series
models. All 6500 Series models use "Stopmaster"
brakes at rear axle. Brake assembly can be re­
moved as a complete assembly; however, the var­
ious components must be replaced individually.
The brake assembly is mounted on the brake
spider, which is bolted to flange on axle housing.
Brake assembly shown in figure 25 is atypical
Wagner brake assembly.
G M C S E R V I C E M A N U A L
6 Camshaft and Brake
Chamber Bracket
7 Backing Plate
8 Cam (integral with shaft)
9 Cam Roller
10 Brake Shoe
Figure 2 4 — Front Brake Assem bly
is used on each side of slack adjuster. Whenever
camshaft has been removed, coat bushing surfaces
with S-17 Special Lubricant or equivalent before
installing. After installation, apply lubricant as
directed in LUBRICATION (SEC. 0), and adjust
brake as directed under "Brake Adjustments."
HUBS AND BEARINGS" (SEC. 3D) for removal of
wheels, hubs, and brake drums for access to brake
shoes.
"S" C AM REAR BRAKES
HUBS AND BEARINGS" (SEC. 4C) for removal of
wheels, hubs, and brake drums for access to brake
shoes.
two shoe webs welded in place. At anchor end,
shoe webs straddle the mounting flange on brake
spider and pivot on anchor pins. Anchor pins are
11 Brake Shoe Return Spring
12 Guide Pin Washer
13 Guide Pin "C" Washer
14 Guide Pin
15 Lock Ring
16 Anchor Pin
Refer to "Front Suspension" under "FRONT
BRAKE SHOES A N D ANCHOR PINS
(Refer to Figure 25)
Refer to "Rear Suspension" under "REAR
Each brake shoe consists of a shoe table with
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