Failure and maintenance measures of hydraulic pump of Kobelco excavator

- Jul 01, 2020-

The serious wear of the hydraulic pump of the excavator has a fatal impact on the excavator. Such problems of the excavator must be resolved in time.

Usually, the pump and the regulator, the auxiliary valve and the auxiliary pump are installed together, which makes it very difficult to troubleshoot the fault. Checking the following items makes it easier to find the fault.

Identify the cause of the failure

1. Check the filter element and drain oil. Check whether the filter element is contaminated. In the process of brake shoe and cylinder wear, some metal substances will precipitate in it. If there is too much metal substance, the filter element is very easy to damage. In this case, the oil in the pump cover To be checked.

2. Check for abnormal sound and vibration. Check whether the pump vibrates and makes abnormal noise, check whether the vibration of the regulator and the vibration frequency of the overflow valve connected to the valve are normal. If it is not normal, the pump may be forming cavitation or internal rupture.

Fault detection and handling

1. The engine is overloaded.

2. After 30 minutes of flushing, replace the oil return filter again and observe whether the above three items are accurate.

3. If two single pumps or motors are used, or one dual pump is used, change the pump pipeline to find out whether the pump is malfunctioning or the circuit connecting the pump is malfunctioning.

4. Pressure measurement. If the fault occurred is related to the control function, the cause of the fault can be identified by measuring the pressure.


1. Pump oil flow rate is too low and no output pressure fault





The regulator  is not working properly

 Correction   regulator

Pump parts stuck or damaged

Replacement  of  damaged parts

Check the  filter element and oil

The auxiliary pump is not operating normally

Replacement  of  damaged parts

Remove the  attached pump and check the coupling

The auxiliary pump is not operating normally

Inspect  attached pumps, especially cone-centered seats and springs

Regulator piping error

Correct cloth tube


2. Troubleshooting of abnormal sound and vibration





          Air pockets

Prevent  cavitation and check for contamination of hydraulic fluid

1. The lower

2. Attached pump failure

3. Suction pipe takes in  air

4. High suction adhesion

The filling  part of brake shoe is broken

Replace piston shoe and brake shoe

Check the  filter element and oil

Cylinder  rupture

Replace the cylinder

Improper pump  installation

Correct  installation

Regulator  vibration

Repair regulator

The relief  valve with the auxiliary valve vibrates

Repair the  attached valve