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Rev. B
Sand Pro 2020/3020/5020Hydraulic System (Rev. A) Page 4 – 16
Troubleshooting
The table that follows contains information to assist in
troubleshooting. There may possibly be more than one
cause for a machine malfunction.
Refer to the Testing section of this Chapter for precau-
tions and specific test procedures.
Problem Possible Cause
Hydraulic oil leaks from the system. Fitting(s), hose(s), or tube(s) are loose or damaged.
O–ring(s) or seal(s) are missing or damaged.
Hydraulic fluid foams. Oil level in tank is low.
Hydraulic system has wrong type of oil.
One of the pump suction lines has an air leak.
Hydraulic system operates hot. Oil level in tank is low.
Oil is contaminated or too light.
Heat exchanger is damaged or plugged.
Accelerator valves leak from high pressure to low pressure side.
Charge pressure is low due to the following possible causes:
Oil filter is clogged.
Charge relief valve is defective.
Implement relief valve is defective.
Charge pump is defective.
Traction pump outlet pressure is high due to the following possible
causes:
Wheel load is to high or brakes are applied.
Traction pump is worn or damaged.
Shuttle valve in RH rear wheel motor is stuck or faulty.
Wheel motor(s) are worn or damaged.
Unit operates in one direction only. External control linkage is misadjusted, disconnected, binding, or
damaged.
Charge check valve in hydrostat is defective.
Acceleration valves in hydrostat are defective.
Neutral is difficult to find. External control linkage is misadjusted, disconnected, binding, or
damaged.
Wheel motor will not turn. Internal parts in wheel motor are damaged.
Brakes are binding.
Key on wheel motor shaft is sheared or missing.