Specifications

Vehicle System Testing & Adjusting 54
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 the line circuit.
5. Unit being held in relief mode for long periods of
time.
Power Master Cylinder
Problem: Low power braking pressure or loss of
power braking
Probable Cause:
1. Insufficient pedal stroke.
2. Lines connected to wrong ports.
3. Insufficient brake flow from the first section of
control valve due to a stuck brake spool.
4. Relief valve in brake valve damaged.
5. Seals of servo piston in brake valve got damaged.
Problem: Low manual braking pressure or loss
of manual braking
Probable Cause:
1. Insufficient pedal stroke.
2. Air in lines.
3. Damaged servo piston seals and sleeve due to
contamination.
Problem: Pedal instability
Probable Cause:
1. Air in lines.
2. Damaged a check valve of brake port in the first
section of control valve.
3. Damaged a spring of relief valve in brake valve.
4. Damaged a spring for brake spool in the first
section of control valve.
Problem: External leakage
Probable Cause:
1. Damaged master piston or seal of master piston.
2. Casting porosity.
3. Fitting or line leakage.