Vehicle Systems
Testing and Adjusting
48
Problem: The temperature of the oil is too hot.
Probable Cause:
1.
The viscosity of the oil is wrong.
2.
Air mixed with the oil.
3.
The relief valve is set too high (priority valve).
4.
There is a restriction in line circuit.
5.
Unit being held in relief mode for long periods of
time.
Brake System
Problem: Brakes make noise or pull (grab).
Probable Cause:
1.
Brake shoe adjustment not correct.
2.
Lining surface looks like glass (glazed) or is worn.
3.
Oil or brake fluid is on the lining.
4.
Dirt on the brake drum lining surface.
5.
Brake drum is badly worn or has grooves (scored).
6.
Restriction in the brake line.
7.
Brake drum is out of round.
Problem: Both brake shoes will not release all
the way (drag).
Probable Cause:
1.
Brake shoe adjustment not correct.
2.
Brake pedal adjustment not correct.
3.
Mechanical resistance at the pedal or shoe.
4.
Restriction in brake line.
5.
Bad wheel cylinder.
Problem: Pedal resistance is not solid (spongy).
Probable Cause:
1.
Leakage or low fluid level.
2.
Air in the brake hydraulic system.
3.
Loose master cylinder mounting.
Problem: Hard pedal.
Probable Cause:
1.
Mechanical resistance on the pedal or shoe.
2.
Brake shoe adjustment not correct.
3.
Restriction in the brake line.
4.
Bad master cylinder.
5.
Lining surface looks like glass (glazed), or is worn.
Problem: Pedal gradually goes to the floor.
Probable Cause:
1.
Leakage or low fluid level.
2.
Bad master cylinder.
Problem: Extra (excessive) pedal travel.
Probable Cause:
1.
Leakage or low fluid level.
2.
Air in the brake hydraulic system.
3.
Bad master cylinder.
4.
Lining surface looks like glass (glazed), or worn.
5.
Operation of brake adjuster is not correct.
