I. Oil Pump Noise and Vibration

◆ Causes:

1. The oil pump motor does not share the center as expected.

2. The coupling is loose.

3. The oil pump inside is faulty.

4. The oil level is too low and air is sucked in from the oil-filter screen or connector connection point into the oil.

5. Air is sucked in from the motor driving shaft.

6. Oil jams the oil-filter screen.

7. The oil return pipe is loose and sucks air in or the pipe is over the oil level, which results in air being mixed into the oil.

◆ Solutions:

1. Adjust the concentricity to within 0.1 mm.

2. Fix the coupling.

3. Fix or replace the oil pump.

4. Add oil to more than 400 mm over the oil-filter screen and connector.

5. Replace the sealing ring of the driving shaft.

6. Clean the oil-filter screen and filter the oil.

7. Fasten the oil return pipe and stick the oil return pipe under the oil surface.

II. Motor Noise

◆ Causes:

1. The motor bearing is broken.

2. There is a motor coil winding fault.

3. The motor is wrongly connected, the system pressure rises and the noise increases.

◆ Solution:

1. Replace the connecting bearing.

2. Replace or fix the motor.

3. Reconnect the motor based on wiring diagram.

III. Noise from the King Pressure Valve (Relief Valve)

◆ Cause:

1. There is air in the front cavity of the pilot valve of the relief valve.

2. The damping hole at the center of the main valve of the relief valve is jammed by oil.

3. The pilot valve and the valve base are not tightly fitted together.

4. The spring deforms or is incorrectly installed.

5. There is too much oil flow at the remote control opening.

6. The viscosity of the hydraulic oil is too low or high.

7. There is a resonance with the circuit components.

◆ Solutions:

1. Fix the sealing and increase and decrease the commissioning pressure repeatedly for air expelling.

2. Wash the valve to clean the hole.

3. Fix or replace the related parts.

4. Check, repair and replace the spring.

5. Reduce the oil flow of the remote control opening.

6. Replace the hydraulic oil.

7. The set pressure for other components cannot be close to that of the relief valve.

IV. Noise from Hydraulic Cylinder

1. When there is air mixed in the oil or the air in the hydraulic cylinder is not completely exhausted, noise can be caused by cavitation due to high pressure. At this point, the air must be exhausted in time. 

2. If the oil seal of the cylinder head is too tight or the piston rod is bent, noise can be caused during movement. Replace the oil seal or straighten the rod in time.

V. Pipe Noise

Pipe noise is usually caused by too many excessive dead bending positions of the hydraulic pipe or loose fastening ferrules. Therefore, dead bending should be avoided in the hydraulic pipe line and timely check the tightness of the fastening ferrules.