Page K-12
Repair and Service Manual
B
MECHANICAL BRAKES
Read all of Section B and this section before attempting any procedure. Pay particular attention to Notices, Cautions, Warnings and Dangers.
To perform an Aggressive Stop Test, equally load both
sides of the vehicle (Ref. Fig. 13) and apply maximum
force and travel to the service brake pedal while moving.
Do not latch the parking brake. Do this a total of 10 times
with the first few at slow speed. If brake function is ade-
quate or improves, increase speed for the remaining
tests. Before the end of the tests, both wheels should
lock at approximately the same time and slide straight.
The brake adjuster mechanism must expand and release fully
to function. Under light usage this may not occur, even though
the vehicle stops acceptably. The adjuster functions most con-
sistently with aggressive braking.
Fig. 13 Equally Load Vehicle
Wheel Brake Inspection
Wear a dust mask and eye protection whenev-
er working on wheel brakes. Do not use pres-
surized air to blow dust from brake assemblies.
Replace both brake shoes on both wheels if
o n e o r m o r e s h o e s a r e w o r n b e l o w . 0 6 ”
(1.5mm) thickness at any point.
Do NOT touch any of the wheel brake mechanism except
as instructed.
Do NOT use a commercial brake cleaner unless the
entire brake has been disassembled.
1. Remove the brake drums.
Do not disturb adjuster mechanisms. Remove excess
dust and dirt from the drum with a brush.
The drum must not be turned to “true” a worn
friction surface. Turning will make the drum too
thin causing drum failure and a loss of brakes
which could cause severe injury or death.
2. Inspect the brake drum.
Look for a blue coloration or blistered paint that would
indicate that it has overheated. Check for evidence of
scoring. Check for excessive wear indicated by the
friction surface being significantly worn and leaving a
ledge of unworn drum. Inspect the splines for galling,
wear and corrosion. If any of these problems are
found, the drum must be replaced.
3. Remove any accumulated brake dust from the wheel
brake assembly with a brush.
4. Visually inspect the axle seal for oil leakage and the
condition of the thrust washer. If oil is present, see
REAR AXLE section.
5. Verify the inner brake drum washer is present and
check its condition. Replace if damaged or missing.
If one wheel brake assembly requires replace-
ment, the second must also be replaced.
Use care when handling the adjuster arm. Too much
force will damage the adjuster and require that both
wheel brake assemblies be replaced.
6. Visually check the condition and operation of the
adjuster mechanism.
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).
NOTICE
A Textron Company
Summary of Contents for EXPRESS L6 2012
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