TM 5-3895-382-24
Problem: Parking brake does not release when parking
brake button is pulled up.
Probable Cause:
1.
Failure of the parking brake button.
2.
Worn or damaged piston seal in the brake group.
3.
Failure of the parking brake valve.
4.
Fault in the electric circuit.
5.
Failure of neutral start switch.
6.
Failure of neutral start relay.
7.
Failure of brake relay.
8.
Steering pump relief valve damaged or incorrectly
adjusted.
9.
Failure of the steering pump.
Problem: Parking brake does not engage when the parking
brake button is pushed down.
Probable Cause:
1.
Failure of the parking brake button.
2.
Failure of brake relay.
3.
Worn brake discs.
4.
Failure of the parking brake valve.
5.
Fault in the electric circuit.
Problem: Noisy drum drive motor.
Probable Cause:
1.
If the motor gives off a regular humming noise, the shaft
bearings are bad.
2.
If there is excessive vibration, the retaining bolts are
loose.
3.
If the motor gives off noise (banging sounds), the
charge pressure from the steering pump is too low.
Problem: External oil leaks from drum or axle propel
motors.
Probable Cause:
1.
Motor case pressure is too high.
2.
Restriction in the oil return line to hydraulic tank.
3.
Faulty thermal bypass valve.
4.
Seals damaged due to pressure peaks, use of
unapproved hydraulic oil which is not compatible with
the seal material or incorrect tightening torque values.
Problem: Propel system oil overheats.
Probable Cause:
1.
Incorrect type of oil used in the hydraulic circuit.
2.
The oil cooler is internally restricted.
3.
The oil cooler is externally restricted.
4.
Excessive internal leakage in circuit which causes low
charge line pressure.
5.
Thermal bypass valve is not shifting to allow hot oil to
flow through the oil cooler.
6.
Operating pressures exceeding relief pressures due to
mechanical problems.
Problem: Main relief valve pressures are not correct.
Probable Cause:
1.
Low charge pressure.
2.
The shuttle or relief valves in the flushing valve stuck.
3.
Internal damage to front gear reducer or rear propel
motor.
4.
Damage to end reduction case, carrier, or wheel
assemblies.
5.
Damage to drum support assembly on vibratory side of
drum.
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