Mitsubishi MS140-2 Excavator Swing Issues and Solutions

[MikePhua]

When the swing system of the Mitsubishi MS140-2 excavator malfunctions, it can lead to delayed or stuck swinging motions or a complete loss of swing function. This not only impacts the machine’s work efficiency but may also cause further damage to other systems. Therefore, understanding the common causes and solutions for swing system failures is essential for proper maintenance.
Common Issues and Causes

1. Slow or Sticking Swing Motion
   If the swing motion becomes slow or sticks, it is usually caused by blockages in the swing hydraulic line, wear in the swing motor, or insufficient hydraulic oil. The hydraulic pump may fail to provide enough pressure to operate the swing system smoothly.
   
2. Complete Loss of Swing Function
   When the swing system fails entirely, it is typically due to a serious hydraulic system issue, such as hydraulic oil leakage, electrical control system malfunction, or a damaged swing motor. This prevents the hydraulic system from supplying oil to the swing, resulting in a loss of function.
   
3. Unusual Swing Noise
   Abnormal noise during the swing operation may indicate severe wear inside the swing motor or contamination of the hydraulic oil. The pump may fail to provide steady pressure, and excessive noise can impact the working environment, possibly leading to further damage to the swing system.
   

Troubleshooting and Solutions

1. Check Hydraulic Oil Level and Quality
   Insufficient hydraulic oil or oil contamination can cause swing system failures. Start by checking the hydraulic oil level to ensure it is adequate. If the oil is dirty or degraded, replace it with fresh oil.
   
2. Inspect Swing Hydraulic Lines
   Examine the swing hydraulic lines for any blockages or leaks to ensure smooth oil flow. If any hoses are damaged or worn out, replace or repair them promptly.
   
3. Inspect the Swing Motor
   A damaged swing motor is a common cause of swing system failure. If the swing system has completely stopped working, inspect the swing motor to determine if it is functioning correctly. Disassemble the motor to check internal components, and replace it if necessary.
   
4. Check Hydraulic Pump and Electrical Control System
   Ensure the hydraulic pump is providing adequate pressure, and verify that the electrical control system is functioning properly. If the pump or control system is faulty, repair or replace the components.
   
5. Clean or Replace the Hydraulic Oil Filter
   If there is unusual noise in the swing system, check the hydraulic oil filter for blockages. Regularly clean or replace the filter to ensure the hydraulic oil remains clean and the system runs smoothly.
   

Conclusion
Common issues with the Mitsubishi MS140-2 excavator swing system include slow or stuck swings, complete loss of swing function, and abnormal noise. By checking the hydraulic oil, hydraulic lines, swing motor, hydraulic pump, and electrical control system, these problems can be diagnosed and resolved. Regular maintenance and prompt repairs of the swing system will help improve the machine’s operational efficiency and extend its service life.