Chevrolet 10 Series 1967, Service Manual

Page: 237 / 605

BRAKES 5-21
Fig. 38—Backing Plate C ontact Surfaces
Fig. 39—Using Drum to Brake Shoe C lea ra n ce G auge
Tool J -21177
first, and then place over the anchor pin stud by
hand while holding the adjuster assembly in full
down position.
11. Install actuator return spring.
NOTE:
Do not pry actuator lever to install
return spring. Ease it in place using the end of
a screw driver or other suitable flat tool.
12. If old brake pull back (return) springs are nicked,
distorted, or if strength is doubtful, install new
springs.
13. Hook springs in shoes using Tool J-8049 by installing
the primary spring from the shoe over the anchor
pin and then spring from secondary shoe over the
wire link end (fig. 37).
14. Pry shoes away from the backing plate and lubricate
shoe contact surfaces with a thin coating of brake
lube (fig. 38).
CAUTION:
Be careful to keep lubricant off
facings.
15. After completing installation, make certain the actu­
ator lever functions easily by hand operating the
self-adjusting feature.
16. Follow the above procedure for all brakes.
17. Adjust the service brakes as outlined below, then
adjust the parking brake.
Adjustment
Although the brakes are self adjusting a preliminary or
initial adjustment may be necessary after the brakes have
been relined or replaced, or whenever the length of the
adjusting screw has been changed. The final adjustment
is made by using the self adjusting feature.
1. With brake drum off, disengage the actuator from the
star wheel and rotate the star wheel by spinning or
turning with a small screwdriver.
Recomm ended Method of Adjustm ent
a. Use special Tool J-21177 or J-22364, Drum to
Brake Shoe Clearance Gauge, to check the dia­
meter of the drum clearance surface (fig. 39).
b. Turn the tool to the opposite side and fit over the
brake shoes by turning the star wheel until the
gauge just slides over the linings (fig. 40).
c. Rotate the gauge around the brake shoe lining
surface to assure proper clearance.
Fig. 40—C hecking Brake Shoe Lining C learan ce
Using Tool J-21177
CHEVROLET TRUCK SERVICE M ANUAL