Troubleshooting Hydraulic Pressure Issues in Excavators: Case of the EX60 URG

[MikePhua]

Hydraulic pressure issues are a common challenge when it comes to the performance of excavators. These systems are responsible for powering critical components like the arm, bucket, and rotation functions, which makes maintaining proper pressure essential for efficient operation. When hydraulic pressure drops or fluctuates, it can lead to sluggish performance, slow response times, or even complete system failure. This article explores how to troubleshoot hydraulic pressure issues using the case of the EX60 URG excavator as an example, offering tips on diagnosing and addressing common pressure-related problems.
Understanding Hydraulic Pressure in Excavators
The hydraulic system in excavators uses high-pressure fluid to transfer energy to various mechanical components. The pressure within the hydraulic system is typically generated by the hydraulic pump, which pumps fluid through the system to power cylinders and motors. Proper hydraulic pressure is critical for efficient lifting, digging, and maneuvering.
Hydraulic systems are designed to operate within specific pressure ranges, and deviations from this range—whether too high or too low—can have significant consequences. Low hydraulic pressure, in particular, can lead to sluggish performance or, in severe cases, a complete failure of the hydraulic system.
Common Symptoms of Hydraulic Pressure Problems
Before diving into specific troubleshooting steps, it's important to recognize the symptoms of hydraulic pressure issues. These problems can manifest in several ways:

1. Slow or Unresponsive Controls
   One of the most common symptoms of hydraulic pressure problems is slow or unresponsive controls. When hydraulic fluid pressure is insufficient, the operator may notice that the arm, bucket, or other components move slowly or fail to respond entirely.
   
2. Erratic Movements or Jittering
   If hydraulic pressure is unstable or fluctuates, it can cause erratic movements or jittering in the machine's operations. For example, the boom or bucket might move in sudden, jerky motions.
   
3. Unusual Noise from the Hydraulic Pump
   A hissing or whining noise from the hydraulic pump can indicate a problem with pressure. This could be due to air in the system or a malfunctioning pump.
   
4. Leaks Around Hydraulic Components
   Leaks around the hydraulic pump, hoses, or cylinders can result in a drop in pressure. This is usually accompanied by visible fluid loss.
   
5. Warning Lights or Pressure Gauges
   Most modern excavators are equipped with pressure gauges or electronic systems that will trigger a warning light if the hydraulic pressure drops below a safe level.
   

Diagnosing Hydraulic Pressure Issues in the EX60 URG
When encountering hydraulic pressure issues, it's important to perform a systematic diagnostic procedure. In the case of the EX60 URG or similar excavators, the following steps can help identify and address the underlying problem.
Step 1: Check Hydraulic Fluid Levels
One of the most common causes of low hydraulic pressure is insufficient fluid. If the hydraulic fluid is low, it can cause cavitation within the pump, resulting in inadequate pressure generation.

• Action: Check the hydraulic fluid reservoir to ensure it's filled to the proper level. If the fluid is low, top it up with the recommended hydraulic fluid for your machine.
  
• Note: Always use the correct type of fluid specified by the manufacturer to avoid damage to the system.
  

Step 2: Inspect for Leaks
Hydraulic fluid leaks are another common cause of pressure loss. These leaks can occur at various points in the system, including hoses, fittings, cylinders, and the hydraulic pump itself.

• Action: Visually inspect the hydraulic hoses and fittings for any signs of leaks. Look for drips or fluid accumulation around the pump, valves, and cylinders.
  
• Tip: In some cases, using a soap-and-water solution on suspected leak areas can help identify leaks by bubbling.
  

Step 3: Examine the Hydraulic Pump
The hydraulic pump is the heart of the system and plays a critical role in generating pressure. If the pump is worn out or malfunctioning, it can fail to generate the required pressure.

• Action: If you're experiencing low or fluctuating hydraulic pressure, consider inspecting the hydraulic pump. Listen for unusual noises like whining or grinding, which could indicate internal damage or wear.
  
• Tip: Checking the pump’s internal components may require disassembling parts of the hydraulic system, so it’s advisable to consult the machine’s service manual or seek professional assistance.
  

Step 4: Test the Pressure Relief Valve
The pressure relief valve is an essential component that ensures the hydraulic system does not exceed its maximum pressure. If the valve is faulty or stuck, it can cause irregular pressure levels, leading to performance issues.

• Action: Test the pressure relief valve to ensure it is functioning properly. This can be done by measuring the pressure output with a pressure gauge.
  
• Tip: If the pressure relief valve is set too low or stuck, adjusting or replacing the valve should restore normal hydraulic pressure.
  

Step 5: Inspect the Hydraulic Filters
Clogged or dirty hydraulic filters can restrict the flow of fluid, resulting in a drop in pressure. Over time, debris and contaminants can build up in the filters, leading to poor system performance.

• Action: Inspect and replace the hydraulic filters if they appear clogged or dirty. Ensure that the filters are the correct type and size for the EX60 URG excavator.
  
• Tip: Regularly replacing the filters as part of your maintenance schedule can prevent pressure-related issues from arising.
  

Step 6: Check for Air in the Hydraulic System
Air trapped in the hydraulic system can cause erratic pressure fluctuations, leading to poor performance. This is often caused by leaks or improper fluid filling.

• Action: Bleed the air from the hydraulic system by following the procedures outlined in the operator’s manual.
  
• Note: Make sure to properly fill the system with hydraulic fluid to avoid air pockets forming.
  

Fixing Hydraulic Pressure Issues
Once the source of the hydraulic pressure problem is identified, it’s time to address the issue. Depending on the specific fault, the repair process may vary:

• Fluid Level: If low fluid is the issue, simply top it up with the correct type of hydraulic fluid. Be sure to check for leaks that may have caused the fluid loss.
  
• Leaks: Repair or replace any leaking hoses, fittings, or seals. If the leak is severe, the damaged component may need to be replaced entirely.
  
• Hydraulic Pump: If the pump is damaged, it may need to be rebuilt or replaced. Be sure to inspect the pump’s components and check for worn-out seals or internal damage.
  
• Pressure Relief Valve: Adjust or replace the pressure relief valve if it’s not operating correctly. This will ensure that the system operates within the correct pressure range.
  
• Filters: Replace any clogged or dirty hydraulic filters to ensure proper fluid flow through the system.
  
• Air in System: Bleed the system to remove any trapped air and restore consistent pressure.
  

Preventive Maintenance Tips
To prevent future hydraulic pressure issues in the EX60 URG or similar excavators, follow these preventive maintenance tips:

• Regular Fluid Checks: Frequently check the hydraulic fluid level and quality to ensure the system operates at peak performance.
  
• Scheduled Maintenance: Follow the manufacturer’s recommended maintenance schedule for fluid changes, filter replacements, and component inspections.
  
• Leak Prevention: Inspect hydraulic hoses and fittings regularly for signs of wear or damage. Replace parts as necessary to avoid leaks.
  
• System Bleeding: Make sure the hydraulic system is properly bled after any maintenance or fluid replacement to avoid air-related pressure issues.
  

Conclusion
Hydraulic pressure issues can significantly affect the performance of an excavator, but they can often be resolved with proper troubleshooting and repairs. In the case of the EX60 URG, following a systematic approach to diagnosing pressure issues—starting with fluid levels and progressing through pump inspections and pressure relief valve testing—can help ensure the machine remains operational. Regular maintenance and prompt repairs will keep hydraulic systems in top shape, preventing downtime and costly repairs in the future.