Bendix Commercial Vehicle Systems A2LS HYD DRUM BRAKES W/PARKING 2/08 User Manual
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DRUM BRAKE TROUBLESHOOTING
SYMPTOM
CAUSE
REMEDY
6.
Scored, hard spotted or out of
6.
Refinish or replace drums in
round drums.
axle sets.
7.
Rough or corroded master
7.
Refer to vehicle service manual.
cylinder bore.
8.
Binding brake pedal linkage.
8.
Refer to vehicle service manual.
9.
Faulty power brake unit.
9.
Refer to vehicle service manual.
5. Vehicle pulls to one
1.
Incorrect or distorted shoes.
1.
Replace with correct shoes in
side.
axle sets.
2.
Incorrect linings or linings loose
2.
Replace with correct shoes in
on shoes.
axle sets.
3.
Grease or brake fluid on linings.
3.
Replace grease seal, wheel
cylinder or expander as
necessary. Replace brake shoes
in axle sets.
4.
Shoes not centered in drums.
4.
Adjust steady post.
5.
Loose or distorted backing plate
5.
Tighten or replace backing plate
(dirtshield).
(dirtshield).
6.
Scored, hard spotted, or out of
6.
Refinish or replace drums in
round drums.
axle sets.
7.
Water on linings.
7.
Apply brakes several times to
dry linings.
8.
Sticking wheel cylinder piston.
8.
Replace or repair wheel cylinder.
9.
Faulty suspension parts.
9.
Refer to vehicle service manual.
6. Noise and chatter.
1.
Bent, damaged, or incorrect
1.
Replace with correct shoes in
shoes.
axle sets.
2.
Worn linings.
2.
Replace with correct shoes in
axle sets.
3.
Broken shoe return spring.
3.
Replace shoe return springs.
4.
Rough, grooved, or dry shoe
4.
Smooth shoe abutment surfaces
abutment surfaces or steady
and steady post with emery
post on dirtshield.
cloth and lubricate with brake
lubricant.
5.
Cracked or threaded drums.
5.
Replace drums in axle sets.
7. Pulsating brake
1.
Out of round drums.
1.
Refinish or replace drums in
pedal.
axle sets.
2.
Bent axle.
2.
Refer to vehicle service manual.
3.
Worn or damaged wheel
3.
Refer to vehicle service manual.
bearings.
4.
Defective master cylinder.
4.
Refer to vehicle service manual.
5.
Brakes overadjusting.
5.
Adjust brake shoes and repair
automatic adjuster if necessary.
8. Decreasing pedal
1.
Weak or broken shoe return
1.
Replace shoe return springs.
travel.
spring.
2.
Sticking wheel cylinder piston.
2.
Repair or replace defective wheel
cylinder.