GMC 4000 Series Service Manual page 197

Sec. 5A
Page 190
HYDRAULIC BRAKES
Figure 3 0 — Installing Primary Shoe Return Spring
from brake shoe contact surfaces on backing plate
using fine emery cloth.
4. Inspect brake shoe return springs. If broken,
cracked, or weakened, replace springs.
5. If lining is worn to the extent that replace­
ment is necessary, replace lining as directedunder
"Brake Shoe Relining."
BRAKE SHOE INSTALLATION
1. Inspect new brake shoe and lining assem ­
blies and make sure there are no nicks or burrs
on edges of shoes which contact backing plate.
NOTE: Keep hand clean while handling brake
Figure 3 1 — Brake Shoe Contact Surfaces a n d B a ck in g Plate
G M C S E R V I C E M A N U A L
shoes. Do not permit oil or grease to come in con­
tact with linings.
ing spring and place adjusting screw assembly in
position.
against backing plate so that primary shoe (short
lining) is toward front of vehicle. Secondary shoe
(long lining) is toward rear of vehicle.
cylinder rods.
hold-down pin, spring and washers.
ing pivot and override spring) in position on sec­
ondary shoe and attach both shoe and actuating
lever assembly to backing plate with hold-down
pin, spring, and washers.
---- 7. Install guide plate over anchor pin.
Figure 3 2 — Checking Operation of Actuating Lever
2. Connect brake shoes together with connect­
CAUTION: Make sure the proper
adjusting screw assembly is used (left-
or right-hand). The adjusting screw a s ­
sembly must be installed with the star
wheel (adjusting screw) nearest to the
secondary shoe. The connecting spring
must be installed with the long end hooked
on the secondary shoe, so that the spring
coils will not interfere with movement of
star wheel.
3. Spread brake shoes apart at top and place
4. Insert brake shoe webs into slots in wheel
5. Secure primary shoe to backing plate with
6. Place the actuating lever assembly (includ­
8. Install actuating link.