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SYMPTOM
1. Low Pedal.
2. Springy or spongy
pedal.
3. Hard pedal.
4. Grabby brakes.
14
DRUM BRAKE TROUBLESHOOTING
CAUSE
1. Excessive clearance between
drums and linings.
2. Automatic adjusters not
working.
3. Bent or distorted brake shoes.
4. Leak in hydraulic system.
5. Air in hydraulic system.
6. Low brake fluid.
7. Weak brake hoses.
1. Bent or distorted brake shoes.
2. Shoes not centered in drums.
3. Cracked or thin drums.
4. Air in hydraulic systems.
5. Weak brake hoses.
6. Drums out of round.
1. Grease or brake fluid on linings.
2. Glazed linings.
3. Damaged or distorted shoes.
4. Scored, barrel-shaped, or
bell-mounted drums.
5. Defective master cylinder or
other brake system components.
1. Incorrect or distorted shoes.
2. Incorrect linings or lining loose
on shoes.
3. Grease or brake fluid on linings.
4. Shoes not centered in drums.
5. Loose or distorted backing plate
(dirtshield).
REMEDY
1. Adjust brakes.
2. Make several forward and
reverse stops; if pedal does not
come up, repair automatic
adjusters.
3. Replace shoes and linings in axle
sets.
4. Refer to vehicle service manual.
5. Bleed system; refer to vehicle
service manual.
6. Fill master cylinder. If
necessary, bleed system. Refer
to vehicle service manual.
7. Refer to vehicle service manual.
1. Replace shoes and linings in
axle sets.
2. Make certain shoe webs are
seated in tappet or piston slots.
3. Replace drums in axle sets.
4. Bleed system; refer to vehicle
service manual.
5. Refer to vehicle service manual.
6. Refinish, or replace if wear
exceeds limits.
1. Replace grease seal, wheel
cylinder, or expander as
necessary. Replace brake shoes
in axle sets.
2. Sand lining surfaces or replace
shoes and linings in axle sets.
3. Replace brake shoes in axle sets.
4. Refinish or replace drums in
axle sets.
5. Refer to vehicle service manual.
1. Replace with correct shoes in
axle sets.
2. Replace with correct shoes
in axle sets.
3. Repair grease seal, wheel
cylinder, or expander as
necessary. Replace brake shoes
in axle sets.
4. Adjust steady post.
5. Tighten or replace backing plate
(dirtshield).
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