Midi Excavator Hydraulic Issues: Identifying Common Problems and Solutions

[MikePhua]

Introduction
When operating a midi excavator, it’s important to be aware of the potential hydraulic issues that can affect its performance. A user posted a concern about whether a particular issue with their midi excavator’s hydraulics was normal or indicated a deeper problem. This article will break down the potential causes of hydraulic malfunctions, how to identify them, and what steps to take to resolve them.
Understanding Hydraulic Systems in Midi Excavators
Midi excavators rely heavily on hydraulic systems to operate efficiently. These systems control various functions such as boom movement, arm extension, bucket operation, and rotation. The hydraulic system consists of hydraulic pumps, valves, cylinders, hoses, and filters that all need to work in harmony to ensure smooth operation.
Common Symptoms of Hydraulic Problems

1. Slow or Weak Movement
   • Issue: If the excavator’s arm, boom, or bucket is moving slower than usual or requires more effort to operate, this could indicate a hydraulic issue.
     
   • Possible Causes: Low hydraulic fluid levels, air in the hydraulic system, or worn-out hydraulic pumps.
     
   • Solution: Check the fluid levels and top them up if necessary. Ensure the fluid is clean and free from contaminants. If the problem persists, consult a mechanic to check for worn components.
     
2. Unusual Noises
   • Issue: Grinding, whining, or screeching noises from the hydraulic system could suggest issues with the hydraulic pump or motor.
     
   • Possible Causes: Air trapped in the system, low oil levels, or cavitation (a phenomenon where bubbles form in the fluid and collapse under pressure).
     
   • Solution: Bleed the hydraulic system to remove any trapped air. Also, check the hydraulic pump and filters for wear and tear.
     
3. Leaks
   • Issue: Fluid leaking from any part of the hydraulic system is a clear sign of malfunction.
     
   • Possible Causes: Worn seals, loose connections, or cracked hoses.
     
   • Solution: Inspect the system carefully for leaks. Replace any damaged seals or hoses, and tighten connections to stop the fluid loss.
     
4. Erratic or Unresponsive Controls
   • Issue: If the controls for moving the excavator’s boom, arm, or bucket feel stiff or unresponsive, it may be a sign that the hydraulic valves are not functioning properly.
     
   • Possible Causes: Blocked or malfunctioning hydraulic valves or control blocks.
     
   • Solution: A professional inspection is required to check the valves and control mechanisms for issues. Cleaning or replacing the valves may be necessary.
     

Is the Issue Normal or Indicative of a Problem?
In the case mentioned by the user, it’s important to first determine whether the hydraulic behavior is standard for the machine’s operation. If the excavator has been working without issue and suddenly shows slower movements or weak power, it could indicate a hydraulic problem rather than a normal condition. To diagnose this:

1. Perform a System Check: Start by checking the hydraulic fluid level. Low fluid is a common cause of sluggish performance. If the fluid is low, top it up and see if the problem resolves.
   
2. Listen for Unusual Sounds: If you hear a strange noise, this is typically an indicator of either air in the system or a pump issue. A mechanic may need to bleed the system or replace the pump if needed.
   
3. Test Hydraulic Functions: Check all hydraulic functions (boom, arm, bucket, etc.). If any are underperforming, it suggests there’s a specific problem in the hydraulic circuit, such as a valve malfunction or a clogged filter.
   

Preventive Maintenance Tips

1. Regular Fluid Checks: Always ensure the hydraulic fluid is at the recommended level and is clean. Replace the fluid periodically as per the manufacturer’s recommendations.
   
2. Inspect Hydraulic Filters: Clogged filters can reduce hydraulic performance. Clean or replace them regularly to keep the system working optimally.
   
3. Monitor for Leaks: Hydraulic leaks should be detected early to prevent larger issues. Regularly inspect the system for signs of leaks or wear.
   
4. Training and Operator Awareness: Ensure that operators are familiar with how the hydraulic system works and are aware of the common signs of malfunction. This can help in early detection and reduce downtime.
   

Conclusion
Hydraulic issues in midi excavators can range from minor to serious, and identifying them early can save time and money. If you notice any symptoms like slow movement, unusual noises, leaks, or erratic controls, don’t hesitate to check the system’s fluid levels, listen for irregular sounds, and look for visible damage. Regular maintenance and a quick response to potential issues can keep your midi excavator running smoothly and prevent more expensive repairs in the future. If you’re unsure, it’s always a good idea to consult with a hydraulic professional for a thorough inspection.