Adjusting Auxiliary Flow on the Hitachi ZX35U-2: A Guide for Operators

[MikePhua]

Introduction: The Hitachi ZX35U-2 and Its Auxiliary Hydraulic System
The Hitachi ZX35U-2 is a compact yet powerful mini excavator that is commonly used in construction, landscaping, and urban development projects. One of its standout features is the auxiliary hydraulic system, which allows operators to use a variety of attachments such as augers, breakers, and trenchers. The ability to adjust the auxiliary hydraulic flow is crucial for ensuring that these attachments work efficiently and deliver optimal performance.
In this article, we will explore how to adjust the auxiliary hydraulic flow on the Hitachi ZX35U-2, discuss why it’s important, and provide some troubleshooting tips for operators to maintain this critical system. Whether you’re working in tight spaces or handling more demanding tasks, properly managing the auxiliary flow can significantly enhance the versatility and effectiveness of your mini excavator.
Why Adjust Auxiliary Flow?
Auxiliary hydraulic flow control is essential for operating various hydraulic attachments. Different attachments require different flow rates, and if the flow is not properly adjusted, you might experience issues such as:

1. Reduced Efficiency: If the hydraulic flow is too low, the attachment might not perform optimally, making the work slower and less efficient.
   
2. Excessive Wear: On the other hand, too much hydraulic flow can lead to overheating, faster wear of both the attachment and the hydraulic components, and possibly even system damage.
   
3. Poor Attachment Performance: Certain attachments, like a hydraulic hammer or auger, require precise flow control to perform their tasks effectively. An incorrect flow rate can cause these tools to operate inefficiently or even fail to function altogether.
   

By adjusting the auxiliary hydraulic flow, you ensure that the machine’s attachments receive the right amount of power to perform their tasks efficiently without causing unnecessary wear and tear on the system.
Adjusting the Auxiliary Flow on the Hitachi ZX35U-2
Adjusting the auxiliary hydraulic flow on the Hitachi ZX35U-2 involves accessing the machine’s settings through its control panel or using the auxiliary control valve. Here’s a step-by-step guide to help you make the adjustment:
1. Locate the Flow Control Valve
The auxiliary hydraulic flow on the ZX35U-2 is controlled by a flow control valve, which is typically located near the hydraulic control valve of the machine. This valve is responsible for regulating the amount of hydraulic fluid delivered to the auxiliary circuit. In some models, this adjustment is available through a control panel inside the operator's cab.
2. Access the Control Panel
For machines equipped with a digital control system, adjusting the auxiliary flow may be done via the operator's control panel. Here’s how:

• Turn on the machine and engage the hydraulic system.
  
• Locate the settings for the auxiliary hydraulic flow on the control panel.
  
• The flow rate is usually displayed in liters per minute (LPM) or gallons per minute (GPM).
  

If you’re unsure where to find this setting, refer to the operator's manual or the manufacturer’s guide to locate the exact menu or dial.
3. Adjust the Flow
Once you’ve located the flow control settings, follow these steps:

• Use the controls to increase or decrease the flow rate, depending on the attachment you are using.
  
• For example, a hydraulic breaker requires a higher flow rate compared to a rotary cutter, so you would adjust the flow accordingly.
  

Adjust the flow in small increments to avoid over-adjusting and damaging the attachment. Keep in mind that excessive flow can cause overheating and underperformance.
4. Test the System
After making the necessary adjustments, test the attachment to ensure that it’s functioning as expected. If the attachment is not operating at full capacity, you may need to fine-tune the flow settings again.
5. Fine-Tune for Optimal Performance
If you are using an attachment that requires high precision, such as an auger, you might need to adjust the flow rate even further. Small changes in flow can have a significant impact on performance, so take the time to test and fine-tune.
Troubleshooting Auxiliary Flow Issues
Even after adjusting the auxiliary hydraulic flow, you might encounter some issues related to performance. Here are some common problems and their solutions:
1. Low Hydraulic Flow

• Cause: If the auxiliary system is not producing enough flow, it could be due to a clogged filter or low hydraulic fluid levels.
  
• Solution: Check the hydraulic fluid level and inspect the filters for blockages. Replace or clean the filters as necessary and top up the hydraulic fluid to the correct level.
  

2. Overheating

• Cause: Excessive hydraulic flow or running high-demand attachments for prolonged periods can cause the hydraulic system to overheat.
  
• Solution: Reduce the flow rate slightly and allow the system to cool down. If overheating persists, inspect the hydraulic oil cooler and check for any blockages or malfunctions.
  

3. Erratic Attachment Movement

• Cause: If the attachment is moving erratically or not performing as expected, it may be receiving an incorrect flow rate.
  
• Solution: Double-check the flow settings and ensure that the rate matches the requirements of the attachment. If needed, perform another fine-tuning adjustment.
  

4. No Flow to the Attachment

• Cause: No flow to the attachment could be due to an issue with the control valve or the hydraulic connection.
  
• Solution: Inspect the auxiliary hydraulic lines for leaks or damage. If the system still isn’t providing flow, check the control valve and consider consulting a technician to troubleshoot further.
  

Case Study: Adjusting Flow for a Hydraulic Breaker
In one case, a contractor working on a demolition project using a Hitachi ZX35U-2 found that their hydraulic breaker wasn’t performing as expected. The breaker was slow to operate and not producing enough force to break through the concrete.
After checking the hydraulic fluid levels and the attachment’s specifications, the operator realized that the flow rate was set too low for the breaker. By increasing the auxiliary flow, the operator was able to bring the breaker to full capacity, allowing the project to move forward smoothly. This simple adjustment saved both time and money by preventing unnecessary delays and repair costs.
Conclusion: Maximizing the Performance of Your Hitachi ZX35U-2
Adjusting the auxiliary hydraulic flow on the Hitachi ZX35U-2 is a simple yet crucial step in ensuring that the machine performs optimally with various attachments. Properly setting the flow rate helps improve efficiency, prevent damage to both the machine and the attachments, and ultimately leads to better results on the job site.
By following the steps outlined above and paying attention to the performance of your attachments, you can optimize your machine’s hydraulic system and maintain its versatility for a wide range of tasks. Whether you’re using a breaker, auger, or trencher, the right flow adjustment can make all the difference in terms of productivity and equipment longevity.
Regular maintenance, along with occasional flow adjustments, will help your Hitachi ZX35U-2 continue to perform at its best, ensuring that you can tackle even the toughest projects with confidence.