B
MECHANICAL BRAKES
Read all of SAFETY and this section before attempting any procedure. Pay particular attention to Notices, Cautions, Warnings and Dangers.
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Repair and Service Manual
699327
6.
Verify that the inner brake drum washer is present
and check its condition. Replace it if it is damaged or
missing.
If one wheel brake assembly
requires replacement, the opposite
must also be replaced.
Use care when handling the adjust-
er arm. Too much force will damage
the adjuster and require that both
wheel brake assemblies be
replaced.
7.
Visually check the condition and operation of the
adjuster mechanism.
8.
Inspect the brake lever for damage or wear. Test the
adjuster function as follows:
•
Push the front brake shoe in the direction of the
rear of the vehicle and hold in position.
•
Operate the brake lever.
•
Observe the brake adjuster arm and note if the
arm engages the star wheel and attempts to
rotate it (Ref Fig. 14)
Fig. 14
.
Adjuster Mechanism
•
If the adjuster arm
engages and turns
the star
wheel, proceed to step 9. If the arm
fails to
engage
the star wheel, it has been damaged
and both wheel brake assemblies must be
replaced.
•
If the adjuster arm engages star wheel but
fails
to rotate it
, the adjuster assemblies must be
replaced with new color-coded adjusters.
•
Note the location of the two Teflon coated wash-
ers (Ref Fig. 21).
9.
Check the condition and operation of the moving
anchor assembly.
•
Operate the brake lever to check for free
motion.
•
The adjuster assembly and brake lever should
move smoothly from front to back on the back-
ing plate.
•
If the moving anchor assembly is damaged or
binds against the backing plate, replace both of
the wheel brake assemblies.
A backing plate assembly that
shows any indication of galling or
gouging is not repairable and must
be replaced with a new wheel brake assembly.
Always replace wheel brake assemblies in pairs.
10. Inspect the backing plate.
•
Inspect for gouges, galling, or other damage,
particularly where the backing plate is con-
tacted by the brake shoes and by the moving
anchor assembly.
•
Replace both backing plates if any gouges or
galling is found.
11. Measure the brake shoe thickness.
•
Measure at the most worn area. Brake shoe
thickness must never be less than .060" (1.5
mm) at any point on the shoe.
•
It is normal for the shoes to show more wear at
the leading and trailing edges (Ref Fig. 15).
•
If the brake shoe thickness is approaching .060"
(1.5 mm), it is recommended that the shoes be
replaced.
•
It is recommended that the brake shoe springs
and brake adjusters be replaced when installing
new brake shoes.
12. Inspect the brake shoe springs.
•
Be sure that the springs are not broken or dam-
aged and are correctly installed.
•
The hooked end of the adjuster spring is
inserted through the front of the front shoe and
the opposite end hooked to the adjuster with the
hook end facing out.
•
The brake shoe springs must be installed with
the light spring closest to the adjuster mecha-
nism with the hook installed down through the
rear brake shoe and up through the front brake
shoe.
•
The heavy top spring is installed with both
spring hooks installed down through the brake
shoes (Ref Fig. 16).
Brake Adjuster
Arm
Star
Wheel
Adjusting
Screw
Front of Vehicle
Wheel Brake Lever
Actuator Piston
Adjuster Housing
PRELIMINARY
