Chevrolet 70 1969 Series, Shop Manual

Page: 210 / 913

BRAKES 5A-17
1 Wheel Cylinder Heat
Shield
2 Upper Wheel Cylinder
3 Anchor Pin
4 Return Spring (Short)
5 Guide Washer
6 Guide Bolt
7 Guide Bolt Nut Lock
Wire
8 Brake Shoe and
Lining Assembly
9 Return Spring (Long)
10 Adjusting Wheel
Lock Spring
11 Adjusting Wheel
12 Lower Wheel
Cylinder
13 Backing Plate TPM-9116
Figure 15— Type “FR-3” Rear Brake Assembly
ing wheel. Adjusting wheels are accessible through
adjusting slots in the backing plate.
B R A K E S H O E R E M O V A L
1. Jack up axle and remove hub and brake
drum assembly as directed in " R E A R HUBS A N D
B E A R IN G S " (SEC. 4C).
2. Install wheel cylinder clamps to hold pistons
in cylinders.
3. Using special brake spring tool (J-8049),
remove brake shoe return springs.
4. Remove lock wires, nuts, and washers
from brake shoe guide bolts, then remove brake
shoe assemblies.
5. Remove screws attaching adjusting wheel
lock springs to anchor supports. Thread each ad­
justing screw from the shoe side of its anchor
support by turning adjusting wheels, then lift ad­
justing wheels out of slots in anchor supports.
C L E A N IN G A N D INSPECTION
1. Clean all dirt out of brake drum. Inspect
drum for roughness, scoring, or out-of-round.
Recondition or replace drum as necessary. Refer
to "Brake D ru m s" in this section.
2. Clean all dirt out of anchor pin holes and
adjusting screw openings in anchor supports.
3. Inspect wheel bearings and oil seals as
directed in " R E A R HUBS A N D B E A R IN G S" (SEC.
4 C).
4. Inspect brake shoe return springs. If broken,
cracked, or weakened, replace with new springs.
5. Inspect threads on adjusting screws and
in adjusting wheels for wear or damage. Replace
as necessary.
6 . Examine brake shoe linings for wear. Lin­
ings should be replaced if worn down close to rivet
heads. Refer to "Brake Shoe Relining" in this sec­
tion.
B R A KE S H O E IN S T A L L A T IO N
1. Install adjusting screws and wheels in
anchor supports dry; use no lubricant. Insert each
adjusting wheel in slot in anchor support, insert
threaded end of adjusting screw in anchor support,
then turn adjusting wheel to thread adjusting screw
into anchor support. Insert anchor pins into holes
in anchor supports, with slots in pins facing slots
in supports.
2. Install brake shoes with cut-away end of
shoe web next to adjusting screw and with ends of
shoes engaging slots in wheel cylinder push rods
and anchor pins. Install flat washer and nut on
each brake shoe guide bolt. Tighten nuts finger-
tight, then back off nuts only far enough to allow
movement of shoes without binding.
3. Install brake shoe return springs, hooking
one end of each spring in brake shoe web, then
hook other end over anchor pins with special brake
spring tool (J-8049).
4. Remove wheel cylinder clamps.
5. Install hub and brake drum assembly as
directed in " R E A R HUBS A N D B E A R IN G S" (SEC.
4C) of this manual.
6. Adjust brakes as directed under "Brake
Adjustments."
BRAKE SHOE RELINING
Brake linings on most models are riveted to
the brake shoes and may be replaced. These linings
may be purchased in replacement sets of four lin­
ings and sufficient rivets of correct specifications.
Refer to Parts Book for lining replacement kits.
When replacing linings, make sure that shoes are
clean and that linings are installed in a manner
that will prevent gaps between lining and shoe.
Conventional lining replacement equipment
should be used. Make sure lining fits firmly against
shoe, and that rivets are properly upset.
N O T E : If brake drums have been refinished,
oversize lining should be used. Refer to "Brake
D r u m s " following:
CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L