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
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8.
Loosen the star wheel to retract the brake shoes and
remove the brake drum.
NOTICE: Pay particular attention to the location of
the inner brake drum washer (6) inside the brake
drum, which may be on the axle shaft or attached to
the rear of the drum hub. This washer must be rein-
stalled when the brake is reassembled.
To install the brake drum:
1.
Clean the axle shaft (5) and the splines on the brake
drum (1) to remove dirt, grease and foreign matter.
2.
Apply a small amount of anti-seize compound to the
axle spline.
3.
Install the inner brake drum washer (6) and slide the
brake drum (5) into place (Ref Fig. 20).
4.
Check to ensure the nose of drum hub is beyond the
end of the axle splines. If not, remove the drum and
install one additional inner brake drum washer (total
of 2) to obtain the required spacing.
Do not back off the castellated nut
to install cotter pin.
5.
Install the remaining hardware and tighten the cas-
tellated nut (3) to the torque values below. Continue
to tighten until a new cotter pin (2) can be installed
through the castellated nut and the hole in the axle.
Maximum torque is 140 ft. lbs. (190 Nm).
Wheel Brake Service
Tool List
Qty.
Socket, 24mm ............................................................. 1
Pliers, Needle Nose..................................................... 1
Brush ........................................................................... 1
Screwdriver, Straight Blade ......................................... 1
Floor Jack.................................................................... 1
Jack Stands................................................................. 2
Torque Wrench, ft. lbs. ................................................ 1
Anti-Seize Compound ............................................. A/N
Brake Cleaner ......................................................... A/N
Multi-Purpose Grease ............................................. A/N
Emery Cloth................................................................. 1
Wheel brake service consists of removal, cleaning,
inspection, lubrication and re-assembly of the wheel
brake. Worn or damaged components must be replaced.
Wheel brake service is required periodically as a pre-
ventive maintenance measure (See SERVICE SCHED-
ULE on page 4). The wear rate of brake shoes and
required service intervals will vary based on usage, ter-
rain, and other conditions. It is recommended that wheel
brake service be performed periodically on a sample of
vehicles within the service fleet to establish the most
efficient and effective service interval.
1.
Remove the brake drum (See Brake Drum Removal
and Installation on page 102).
Wear eye protection and a dust mask
when cleaning the brake
components. Do not use
compressed air to remove brake
dust from the brake assembly.
Do NOT use a commercial brake
cleaner unless the entire brake has
been disassembled.
2.
Remove any accumulated brake dust with a brush.
3.
Remove the brake shoes and adjuster mechanism
(See Brake Shoe and Adjuster Replacement on
page 104).
4.
Clean the backing plate with a commercial brake
cleaner and allow it to dry completely.
It is important that the friction areas
between the backing plate and the
brake shoes are lubricated. Be care-
ful not to allow the lubricant to contact the braking
portion of the brake shoes or the friction surface of
the brake drum. Use only recommended lubricants.
5.
Lubricate the backing plate friction points of the
shoes and moving anchor with multi purpose grease
(MPG) lubricant (Ref Fig. 21).
Fig. 21 Wheel Brake Lubrication Points
Item
Torque Specification
3
80 - 90 ft. lbs. (108 - 122 Nm)
Shim
Washer
Backing Plate
Lubricate
(3) Bosses
Each Side
Lubricate Surfaces In and Around
Slots and Plastic Slide Plate
(2) Teflon
Washers
Adjuster
Housing
Adjuster
Arm
DO NOT LUBRICATE
LUBRICATE
Moving Anchor
Actuator
Piston
Lubricate
(3) Bosses
Each Side
PRELIMINARY