Troubleshooting Hydraulic Issues in the Hitachi EX150 Excavator

[MikePhua]

The Hitachi EX150 excavator is renowned for its robust performance in various construction and excavation tasks. However, like any complex machinery, it can experience hydraulic problems that affect its efficiency and operation. Addressing these issues promptly is crucial to maintain optimal performance and prevent costly repairs.
Common Hydraulic Problems in the Hitachi EX150

1. Machine Vibration Under Load
   Operators have reported that when digging or swinging under load, the entire machine exhibits a shimmying motion, akin to the pump vibrating. This issue often arises when the hydraulic system is under strain, leading to uneven power distribution. Replacing filters and hydraulic fluid can sometimes alleviate this problem, but it's essential to investigate further if the issue persists.
   
2. Engine Power Loss During Hydraulic Operation
   Another common issue is the engine pulling down when hydraulic functions are engaged. This can be indicative of restrictions in the hydraulic lines, faulty relief valves, or air in the system causing pressure loss. Even after replacing the main pump and filters, it's advisable to check for clogged hydraulic lines and ensure proper fluid levels. Bleeding the system to remove any air pockets can also help restore normal operation.
   
3. Swing Hydraulic Issues
   Swing hydraulic problems can manifest as slow or jerky swing movements, uneven rotation, or unresponsive controls. Common causes include leaking or worn swing motors, low or contaminated hydraulic fluid, faulty swing control valves, or worn swing gears and bearings. Regular maintenance, including checking fluid levels, inspecting components for wear, and replacing faulty parts, can help prevent these issues.
   

Diagnostic and Repair Procedures

1. Visual Inspection
   Begin with a thorough visual inspection of the hydraulic system. Look for signs of fluid leaks, damaged hoses, or worn components. Check the condition of the hydraulic fluid; it should be clean and free from contaminants.
   
2. Hydraulic Pressure Testing
   Use a hydraulic pressure gauge to measure system pressures at various points. Compare these readings with the manufacturer's specifications to identify any discrepancies that could indicate issues with pumps, valves, or other components.
   
3. System Bleeding
   If air is suspected in the hydraulic system, perform a thorough bleeding procedure. This involves loosening bleed screws on various components to allow trapped air to escape, ensuring smooth operation of the hydraulic system.
   
4. Component Testing
   Test individual components such as the main pump, relief valves, and swing motors for proper operation. Replace any faulty components with genuine parts to maintain system integrity.
   

Preventive Maintenance Tips

• Regular Fluid Checks: Monitor hydraulic fluid levels and condition regularly. Replace fluid and filters as per the manufacturer's recommendations.
  
• Component Inspections: Periodically inspect hydraulic hoses, fittings, and components for signs of wear or damage. Address any issues promptly to prevent further complications.
  
• System Monitoring: Keep an eye on system pressures and performance during operation. Any deviations from normal operation should be investigated immediately.
  

Conclusion
Hydraulic issues in the Hitachi EX150 excavator can significantly impact its performance and productivity. By understanding common problems, implementing effective diagnostic procedures, and adhering to preventive maintenance practices, operators can ensure the longevity and reliability of their equipment. Always consult the manufacturer's service manual for detailed instructions and specifications tailored to your specific model.