Three types of faults in hydraulic motors

Fault 1: Low Speed ​​and Low Torque

1. Insufficient Hydraulic Pump Oil Supply

（1）The motor speed is insufficient. Identify the cause and adjust it.

（2） The oil suction filter is clogged. Clean or replace the filter element.

（3）Insufficient oil in the tank or the suction pipe is too small, causing oil suction difficulties. Add sufficient oil and increase the pipe diameter appropriately to ensure smooth oil suction.

（4） The seal is not tight and leaks are not occurring, allowing air to enter the pump. Tighten the relevant joints to prevent leakage or air intrusion.

（5）The oil viscosity is too high. Select a lower viscosity oil.

（6）The axial and radial clearances of the hydraulic pump are excessive, causing increased internal leakage. Repair the hydraulic pump as appropriate.

2. Insufficient Hydraulic Pump Output Pressure

（1） Hydraulic pump efficiency is too low. Check for any faults and correct them.

（2）The relief valve is not adjusting the pressure correctly or is faulty. Check for any faults and, after correcting them, adjust the pressure back up. 3. Excessive resistance in the oil pipe (the pipe is too long or too thin). Replace the pipe with a larger diameter or minimize its lengt

（3）Excessive resistance in the oil pipe (the pipe is too long or too thin). Replace the pipe with a larger diameter or minimize its length.

（4）The oil viscosity is low and there is significant internal leakage. Check the seals at the leaking area and replace the oil or seals.

3. Hydraulic Motor Leakage

（1）The hydraulic motor mating surfaces are not tightened or the seals are not good, resulting in leakage. Tighten the mating surfaces, check the seals, or replace the sealing rings.

（2） Internal parts of the hydraulic motor are worn and leaking significantly. Check for any damaged parts and repair or replace them.

4. Spring Failure

The support springs on the oil distribution plate are fatigued and no longer functioning. Check and replace the support springs.

Fault 2: Leakage

1. Severe internal leakage

（1）The oil distribution plate is severely worn. Check the contact surface of the oil distribution plate and repair it.

（2） The axial clearance is too large. Check and adjust the axial clearance to the specified range.

（3）The oil distribution plate and the cylinder end face are worn. The axial clearance is too large. Grind the cylinder and the oil distribution plate end face.

（4）The spring is fatigued. Replace the spring.

（5）The plunger and the cylinder are severely worn. Grind the cylinder hole and re-match the plunger.

2.External leakage

（1）The oil end seal is worn. Replace the seal ring and find out the cause of wear.

（2）The seal ring at the cover plate is damaged. Replace the seal ring.

（3）There is dirt on the joint surface or the bolts are not tightened. Check, clean and tighten the bolts.

（4）The pipe joint is not sealed tightly. Tighten the pipe joint.

Fault 3: Noise

（1）Seals are not tight, allowing air to enter the engine. Check the seals and tighten all joints.

（2）Hydraulic oil is contaminated with air bubbles. Replace with clean hydraulic oil.

（3）Coupling is not concentric. Adjust the concentricity.

（4）Hydraulic oil viscosity is too high. Replace with a lower viscosity oil.

（5）The radial dimension of the hydraulic motor is severely worn. Reground the cylinder bore and refit the plunger.

（6）Blades are worn. Repair or replace them if possible.

（7）Blades are not in contact with the stator, causing impact. Trim them.

（8）Stator is worn. Repair or replace it. If excessive wear is caused by an overly stiff spring, replace it with a spring with a lower stiffness.