Excavator machinery parts PC200-7 hydraulic pump solenoid valve 702-21-57400

When the hydraulic pump of the excavator is seriously worn, it has a fatal impact on the excavator, so such problems must be solved in time. Excavator hydraulic pump maintenance from the following three points to find the cause of failure:

(1) Check the internal leakage of the boom cylinder

The simplest way to repair the hydraulic pump of an excavator is to raise the boom and see if it has a significant free fall. If the drop is obvious, remove the cylinder to check, and replace the seal if it has worn out.

(2) Check the control valve

First clean the safety valve, check whether the spool is worn, such as wear should be replaced. If there is still no change after the installation of the safety valve, then check the wear of the control valve spool, the clearance limit is generally 0.06MM, and the wear should be replaced.

(3) Measure the pressure of the hydraulic pump

If the pressure is low, it is adjusted, and the pressure is still not adjusted, it indicates that the hydraulic pump is seriously worn.

Generally, the main reasons why the boom belt load cannot be lifted are:

1. The hydraulic pump of the excavator is seriously worn
The leakage in the pump is serious at low speed. At high speed, the pump pressure is slightly increased, but due to the wear and internal leakage of the pump, the volumetric efficiency is significantly reduced, and it is difficult to reach the rated pressure. The hydraulic pump works for a long time and intensifies the wear, the oil temperature rises, resulting in the wear of hydraulic components and the aging and damage of seals, the loss of sealing ability, the deterioration of hydraulic oil, and finally the failure.

2, the selection of hydraulic components is unreasonable

The boom cylinder specifications are 70/40 non-standard series, and the seals are also non-standard parts, which are high in manufacturing cost and inconvenient to replace the seals. The small diameter of the boom cylinder is bound to make the system set pressure high.