Troubleshooting Auxiliary Flow Issues on Hitachi EX-60-1 Excavator

[MikePhua]

Introduction:
The Hitachi EX-60-1 is a popular compact excavator widely used in construction, landscaping, and digging projects. One of its most critical systems is the auxiliary hydraulic system, which powers attachments like breakers, augers, and grapples. However, operators occasionally face issues with auxiliary flow, especially when it comes to insufficient or erratic hydraulic power. If you're experiencing trouble with your EX-60-1's auxiliary flow, understanding the common causes and troubleshooting steps can help you identify the issue and get back to work.
Understanding the Auxiliary Hydraulic System
The auxiliary hydraulic system on an excavator like the Hitachi EX-60-1 is designed to supply hydraulic power to various attachments. These attachments typically require a high-flow hydraulic system to operate at peak performance. The auxiliary flow is controlled by the machine's hydraulic pump, which is powered by the engine. The flow is then directed through hydraulic lines to the attachment via control valves, which regulate the amount of hydraulic power delivered.
When the auxiliary flow is insufficient, it can lead to poor performance of attachments, such as slow movement or lack of response. This is a serious issue for operators relying on their excavator for tasks that require precise hydraulic control.
Common Causes of Auxiliary Flow Issues

1. Low Hydraulic Fluid Level or Contamination:
   One of the most common causes of low auxiliary flow is low hydraulic fluid levels or contamination. Hydraulic fluid is vital for ensuring smooth movement and pressure within the hydraulic system, and when it is low or contaminated, it can affect the system’s performance.
   • Symptoms of Low Fluid: If the fluid level is low, you may notice a decrease in hydraulic power and performance, with attachments moving slowly or not at all.
     
   • Contaminated Fluid: Over time, dirt, dust, or metal particles can contaminate hydraulic fluid. This results in clogged filters, worn-out seals, and poor pump efficiency.
     
   Real-World Example: A mechanic working on a Hitachi EX-60-1 experienced weak auxiliary flow despite normal operation of the machine’s main hydraulics. Upon inspection, they found the hydraulic fluid was both low and contaminated. After replacing the fluid and cleaning the filters, the auxiliary system's flow returned to normal.
   
2. Faulty Auxiliary Control Valve:
   The auxiliary flow is controlled by a dedicated control valve, which regulates the flow of hydraulic fluid to the attachment. If this valve becomes damaged or worn, it may fail to control the flow properly, leading to weak or inconsistent auxiliary hydraulic performance.
   • Signs of a Faulty Control Valve: If the valve is malfunctioning, you may notice erratic movement or the lack of movement in the attachment. There may also be a noticeable decrease in pressure or a complete failure to power the auxiliary equipment.
     
   • Possible Causes: Over time, seals within the control valve can wear out or become damaged, resulting in leaks or restricted fluid flow. Additionally, debris or dirt can enter the valve, further causing blockages.
     
   Example from the Field: A contractor using a Hitachi EX-60-1 for demolition work reported that their hammer attachment suddenly stopped working correctly. After inspecting the auxiliary hydraulic valve, they found it had a damaged seal, preventing proper flow. Replacing the valve resolved the issue.
   
3. Hydraulic Pump Wear or Failure:
   The hydraulic pump plays a vital role in creating the pressure needed for the auxiliary system. If the pump is worn or malfunctioning, it can result in low hydraulic pressure, which affects the performance of the auxiliary attachments. A drop in the pressure can lead to weak flow, especially under heavy load conditions.
   • Symptoms of Pump Wear or Failure: Common signs of a failing pump include a sudden loss of hydraulic power, strange noises coming from the pump, or erratic movement of the attachments. In some cases, the pump might be able to operate at lower pressure, but under heavier loads, it could fail entirely.
     
   • Causes of Pump Failure: Overheating, poor maintenance, or using the wrong type of hydraulic fluid can all contribute to premature pump wear or failure.
     
   Story from the Field: A seasoned operator working on a road construction project with a Hitachi EX-60-1 noticed that their hydraulic auger attachment was not responding as expected. After investigating, they discovered that the pump had worn out due to improper fluid usage and overheating. The pump was replaced, and the hydraulic system returned to full functionality.
   
4. Blocked or Leaking Hydraulic Lines:
   Hydraulic lines transport fluid between the pump, valve, and attachments. If these lines become blocked or damaged, it can significantly reduce the flow of hydraulic power to the auxiliary system. Leaking lines or connectors can also cause a drop in pressure, leading to insufficient flow.
   • Signs of Blockages or Leaks: If there are leaks, hydraulic fluid may be visible around the hoses or connections. You may also notice a drop in pressure or slower attachment movement. In severe cases, the attachment might stop working entirely.
     
   • What to Check: Check all hydraulic hoses for visible damage or wear. Inspect connections to ensure they are tight and free from leaks. Sometimes, dirt or debris can cause blockages within the lines, so it’s essential to flush the system if blockages are suspected.
     
   Real-World Tip: An operator shared a story about working in a muddy environment with a Hitachi EX-60-1. After several hours of operation, the auxiliary attachment began to show signs of slow movement. Upon inspection, they found that debris had clogged one of the hydraulic lines. After flushing the lines, the flow returned to normal.
   
5. Incorrect Settings or Compatibility Issues:
   Sometimes, issues with auxiliary flow can stem from using the wrong attachment or operating the machine at incorrect settings. For example, attachments requiring more flow than the excavator is capable of providing can lead to poor performance.
   • Common Compatibility Problems: Some attachments, like high-flow augers or breakers, may require a hydraulic system with a higher flow rate than the machine’s auxiliary hydraulics can provide. Ensure that the attachment and excavator are compatible in terms of flow requirements.
     
   Story from the Field: A contractor once attempted to use a high-flow hydraulic hammer with their Hitachi EX-60-1, unaware that the machine’s auxiliary system did not have sufficient flow to operate it effectively. After consulting the manual, they switched to a compatible attachment, and the issue was resolved.
   

Steps to Troubleshoot Auxiliary Flow Issues

1. Check Hydraulic Fluid Levels and Condition:
   Inspect the hydraulic fluid levels and ensure they meet the manufacturer’s specifications. If the fluid is low or contaminated, replace it with fresh, clean hydraulic fluid. Don’t forget to clean or replace the filters during this process.
   
2. Inspect the Auxiliary Control Valve:
   Examine the auxiliary control valve for any signs of damage or wear. If you suspect a malfunction, the valve may need to be serviced or replaced. Check for leaks or dirt inside the valve that could be obstructing flow.
   
3. Examine the Hydraulic Pump:
   Test the hydraulic pump’s performance by checking pressure readings or listening for abnormal noises. If the pump is failing, it may need to be replaced. Ensure that the pump is regularly maintained and that the system is free of contaminants.
   
4. Inspect Hydraulic Lines:
   Inspect all hydraulic hoses and lines for blockages or leaks. Repair or replace any damaged lines, and ensure that all connections are tight and secure.
   
5. Check Attachment Compatibility:
   Ensure that the attachment being used is compatible with the excavator’s hydraulic system. If the attachment requires more flow than the system can provide, consider upgrading the system or choosing a different attachment.
   

Preventative Maintenance Tips

1. Regular Fluid Changes:
   Regularly change the hydraulic fluid according to the manufacturer’s recommendations to prevent contamination and ensure optimal performance.
   
2. Filter and Line Inspections:
   Check and replace filters periodically, and inspect hydraulic lines for wear, leaks, or blockages.
   
3. Proper Attachment Use:
   Always ensure that the attachments you use are compatible with the machine's hydraulic capabilities. Using the wrong attachment can lead to inefficiency or system failure.
   

Conclusion:
Auxiliary flow issues on the Hitachi EX-60-1 excavator can be caused by a variety of factors, including low hydraulic fluid, faulty control valves, pump failure, or blocked hydraulic lines. By following a systematic troubleshooting process and conducting regular maintenance, operators can minimize downtime and keep their equipment running at peak performance. Proper fluid management, regular inspections, and ensuring compatibility between the machine and attachments are key steps in preventing hydraulic issues in the future.