How to Solve the Walking Failure of Doosan DH220-V Excavator

This article mainly introduces how to solve the walking fault of Doosan DH220-V excavator

When the machine is walking in a straight line, the right joystick remains unchanged and the left side

returns to the neutral position (i.e., stops). At this time, the right crawler continues to walk, while the

left crawler slides 800-1000mm before stopping.

1. Checking essentials:

A. After analyzing the hydraulic system, the fault Joints and motors, etc.

B. Measure the system pressure. When the boom is raised to the maximum limit so that the pressure

reaches the maximum, the measured system pressure is 330 BAR, indicating that there is no problem

with the pump.

C. Apply external braking to the walking system. It was also observed that the front pump pressure was

10.5BAR, while the rear pump pressure was 270BAR.

D. After replacing the four main oil lines on the center joint, it was found that the left-hand drive fault

still existed.

E. Based on the above detection, it is concluded that the fault is inside the balance valve, overload

valve and motor. Even after replacing the left and right motor end caps (i.e. balance valve and overload

valve), the fault was still not eliminated.

F. It was concluded that the fault was inside the motor. When the motor was disassembled and

inspected, it was found that there were signs of wear and grooves between the valve plate and the

cylinder barrel.

2. Reason: Internal wear of the motor causes internal leakage of the motor.

3. Processing method: It worked normally after replacing the damaged parts.