Measuring Point's For Shoe Centering; Positioning Actuator Lever - Chevrolet 10 1971 Series Chassis Service Manual

Fig. 55— Measuring Point's For Shoe Centering
5. Remove the brake shoe hold down springs and pins
by compressing the spring with Tool J-22348 and, at
the same time, pushing the pin back through the
flange plate toward the tool. Then, keeping the spring
compressed, remove the lock from the pin with a
magnet (fig. 53).
6. Lift off the brake shoe and self adjuster as an
assembly.
7. The self adjuster can now be removed from the brake
shoe by removing the hold down spring and pin.
The actuating lever, override lever and
NOTE:
spring are an assembly. It is recommended that
they not be disassembled for service purposes
unless they are broken. It is much easier to
assemble and disassemble the brakes leaving
them intact.
8. Thread the adjusting screw out of the anchor support
and remove and discard the friction spring.
9. Clean all dirt out of brake drum. Inspect drums for
roughness, scoring or out of round. Replace or re­
condition drums as necessary.
See Section on "BRAKE DRUMS".
NOTE:
10. Carefully pull lower edges of wheel cylinder boots
away from cylinders. If brake fluid flows out, over­
haul of the wheel cylinders is necessary.
A slight amount of fluid is nearly always
NOTE:
present and acts as a lubricant for the piston.
11. Inspect flange plate for oil leakage past axle shaft
oil seals. Install seals if necessary.
12. Check all flange plate attaching bolts to make sure
they are tight (150 lb. ft. torque). Clean all dirt and
rust from shoe contact faces on flange plate using
emery cloth.
13. Thoroughly clean adjusting screws and threads in
the anchor brackets.
Fig. 56— Positioning Actuator Lever
Installation
1. Put a light film of Lubriplate or equivalent on shoe
bearing surfaces of brake flange plate and on threads
of adjusting screw.
2. Thread adjusting screw
bracket without friction spring to be sure threads
are clean and screw turns easily. Then remove
screw, position a new friction spring on screw and
reinstall in anchor bracket.
3. Assemble self adjuster assembly to brake shoe and
position actuating lever link on override lever.
4. Position hold down pins in flange plate.
5. Install brake shoe and self adjuster assemblies onto
hold down pins, indexing ends of shoes with wheel
cylinder push rods and legs of friction springs.
Make sure the toe of the shoe is against
NOTE:
the adjusting screw (fig. 54).
6. Install cup, spring and retainer on end of hold down
pin. Using Tool J-22348 compress the spring. With
spring compressed, push the hold down pin back
through the flange plate toward the tool and install
the lock on the pin.
7. Using Tool J-22348 install brake shoe return springs.
8. Holding the star wheel end of the actuating lever as
far as possible past the star wheel, position the
adjusting lever cam into the actuating lever link and
assemble with cap screw.
9. Check the brake shoes for being centered by measur­
ing the distance from the lining surface to the edge
of the flange plate at the points shown in Figure 55.
To center the shoes, tap the upper or lower end of
the shoes with a plastic mallet until the distances
at each end become equal.
10. Locate the adjusting lever .020" to .039" above the
outside diameter of the adjusting screw thread by
loosening the cap screw and turning the adjusting
cam.
BRAKES 5-27
completely into anchor
10-30 CHEVROLET TRUCK SERVICE MANUAL