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Sec. 4
Page 58
GM COACH MAINTENANCE MANUAL
AIR BRAKES
6
8
1 Brake Shoe Rollers
2 Cam
3 Brake Shoe Roller
Pins
4 Roller Pin Locks
5 Roller Pin Lock Bolts
6
Upper Brake Shoe and
Lining Assembly
7 Lower Brake Shoe
8 Brake Lining
9
lo
11
12
13
14
4
13
Brake Shoe Spring
Hole Plug
Lining Bolt Hole
Plug
Lining Bolt
Brake Shoe Return
Spring
Anchor Pins
Anchor Pin Lock
Plate
TP-6306
Figure 12-Front Brake Shoes Installed
4. Position cover plates on body and attach
with new rivets. Covers must be flat and in good
contact with body after riveting.
5. Install lubrication fitting in body. Connect
a grease gun to fitting and force grease into slack
adjuster until it is completely filled. Refer to
LUBRICATION (SEC. 13) for type of lubricant.
1 Brake Shoe Roller
2 Roller Pin
3 Roller Pin Lock
4 Lock to Shoe Bolt
5 Bolt Lock Washer
6 Brake Shoe
TP-6201
Figure 13-Brake Shoe Roller Pin Lock Installation
1 Cam
(Integral with
shaft)
2 Spacing Washers
3 Oil
Seals
4
Bearings
5 Brake Spider
6 Camshaft
7 Slack Adjuster
8 Slack Adjuster
Washer
9 Snap Ring
10 Brake Chamber
Push Rod
TP 4503
Figure 14-Front Camshaft and Slack Adjuster Mounting (Typical)
FRONT BRAKE SHOES,
LININGS, AND CAMSHAFTS
SHOES AND LININGS (Fig. 12)
Brakes at each front wheel have two shoes
which pivot on anchor pins at one end and are
expanded at the other end during brake application
by constant lift S-type cams. Brake shoe return
springs hold shoe ends firmly against cam as
shown in figure 12.
Two-piece block type lining
is bolted to each shoe. Holes through linings and
shoes, adjacent to return spring pins, are pro-
vided to facilitate removing and installing springs.
Cam end of each shoe is equipped with a roller
which forms the contact between shoe and cam.
Rollers are mounted on pins which are retained
in shoes by lock plates and cap screws as shown
in figure
13.
Anchor pin ends of shoes are
equipped with replaceable bushings.
ANCHOR PINS (Fig. 12)
Anchor pin end of each shoe fits between
brackets at brake spider, and is retained by
straight type anchor pin.
Both anchor pins are
held in place by a lock plate which fits into notches
near ends of pins and is attached to brake spider
by a cap screw.
Anchor pins are drilled and
threaded for lubrication fittings.
CAMSHAFTS (Fig. 14)
Front brake camshafts are mounted in needle
type roller bearings in brake spiders.
Lubrica-
tion fittings provide method of lubricating bear-
ings.
Lubricant is retained by seals, installed in
brake spider as shown in figure 14.
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