Troubleshooting Hydraulic Problems in the 135SR Kobelco Excavator

[MikePhua]

Hydraulic systems are the heart of any modern excavator, including the 135SR Kobelco. These systems are responsible for powering essential functions such as boom movements, bucket control, and track propulsion. When hydraulic issues occur, they can severely disrupt operations, leading to downtime and costly repairs. The 135SR Kobelco, a widely used compact excavator, is no exception. Operators often encounter various hydraulic problems, ranging from slow movements to complete system failures. In this article, we’ll explore the common hydraulic issues that can arise in the 135SR and how to troubleshoot and resolve them effectively.
Understanding the Hydraulic System in the 135SR Kobelco
The Kobelco 135SR, like most excavators, uses a closed-loop hydraulic system that powers several critical components. These include:

• Main Pump: Provides hydraulic pressure for various functions like the boom, arm, bucket, and swing motion.
  
• Control Valve: Distributes hydraulic oil to various actuators depending on operator input through the joystick controls.
  
• Hydraulic Cylinders: These are responsible for the movement of the boom, arm, and bucket.
  
• Hydraulic Filters and Fluid: Clean fluid and properly functioning filters ensure that the system runs smoothly without contaminants that could lead to wear or failure.
  

The hydraulic fluid used in the 135SR is critical to the system’s performance. The fluid's condition, viscosity, and cleanliness directly impact the efficiency of the system. Hydraulic oil must be changed regularly to prevent contamination, and filters should be cleaned or replaced as part of routine maintenance.
Common Hydraulic Issues in the Kobelco 135SR
Over time, or due to specific operational issues, the 135SR may exhibit various hydraulic problems. These issues can range from minor performance degradation to complete system failure. Some of the most common hydraulic problems include:

1. Slow or Weak Hydraulic Movements
   
2. Erratic Boom or Arm Movements
   
3. Hydraulic Fluid Leaks
   
4. Increased Noise or Vibration
   
5. Hydraulic Warning Lights or Error Codes
   

1. Slow or Weak Hydraulic Movements
One of the most frequent hydraulic issues reported by 135SR owners and operators is slow or weak movements of the boom, arm, or bucket. This issue often arises when there’s insufficient pressure in the system or a loss of hydraulic flow.
Potential Causes:

• Low Hydraulic Fluid Levels: Insufficient fluid levels can lead to low pressure, causing sluggish movements. This may occur due to leaks or poor maintenance.
  
• Clogged Hydraulic Filters: A clogged filter can restrict the flow of fluid, leading to decreased efficiency in hydraulic operations.
  
• Faulty Pressure Relief Valve: If the pressure relief valve is not functioning properly, it can limit the amount of pressure available for hydraulic functions, leading to reduced power.
  

Troubleshooting Steps:

• Check Fluid Levels: Ensure the hydraulic fluid is at the recommended levels. If it is low, inspect for any leaks in the system.
  
• Inspect Filters: Replace or clean the hydraulic filters if they are clogged or dirty.
  
• Test Pressure Relief Valve: Using a pressure gauge, check if the relief valve is operating within specified pressure ranges. Replace if necessary.
  

2. Erratic Boom or Arm Movements
Erratic or jerky movements of the boom or arm are another common issue faced by 135SR operators. These erratic movements can result in unstable operation, affecting precision work and safety.
Potential Causes:

• Contaminated Hydraulic Fluid: Contamination from dirt, debris, or metal shavings can cause erratic movement by interfering with the smooth flow of hydraulic fluid.
  
• Air in the Hydraulic System: Air pockets in the hydraulic system can cause inconsistent operation, often leading to sudden jerks or stalls.
  
• Faulty Hydraulic Pumps: If the pump is worn or malfunctioning, it may not generate sufficient pressure, causing erratic movement.
  

Troubleshooting Steps:

• Check Fluid Condition: Inspect the fluid for any signs of contamination. If the oil appears milky or has a burnt smell, it should be replaced immediately.
  
• Bleed the System: If air in the system is suspected, follow the manufacturer’s procedure to bleed the hydraulic system and remove trapped air.
  
• Inspect Hydraulic Pumps: Check the hydraulic pumps for any signs of wear or damage. Replace the pump if necessary.
  

3. Hydraulic Fluid Leaks
Hydraulic fluid leaks are a common issue in any hydraulic-powered equipment, including the Kobelco 135SR. Leaks can occur in various parts of the hydraulic system, such as hoses, cylinders, or seals, leading to a drop in pressure and performance.
Potential Causes:

• Damaged Hoses or Seals: Over time, hoses can crack or seals can wear out, causing leaks.
  
• Loose Fittings: Loose or improperly torqued fittings may result in fluid leaks.
  
• Corroded Components: Exposure to dirt, debris, and harsh operating conditions can cause corrosion on the hydraulic components, leading to leaks.
  

Troubleshooting Steps:

• Inspect Hoses and Fittings: Examine all hydraulic hoses and fittings for cracks, wear, or loose connections. Tighten or replace as needed.
  
• Check Cylinder Seals: Inspect the hydraulic cylinders for any visible signs of leakage around the seals. If the seals are damaged, replace them to restore system integrity.
  
• Clean Components: Keep the hydraulic components clean to prevent dirt and contaminants from exacerbating leaks.
  

4. Increased Noise or Vibration
Increased noise or vibration coming from the hydraulic system is often an indication of a malfunctioning component or air in the system. Excessive noise can also result from cavitation, which occurs when there is insufficient fluid or air in the pump.
Potential Causes:

• Low Hydraulic Fluid Levels: Low fluid levels can cause cavitation, which is often accompanied by a whining or grinding noise.
  
• Worn Pump: A failing pump can produce excessive noise due to internal wear or damage.
  
• Contaminated Fluid: Contaminated or old fluid can lead to increased friction within the hydraulic components, causing unwanted noise.
  

Troubleshooting Steps:

• Check Fluid Levels: Ensure the hydraulic fluid is at the correct level and top it up if necessary.
  
• Inspect Pump: Listen to the pump for unusual sounds. If the pump is making excessive noise, it may need to be replaced.
  
• Replace Contaminated Fluid: If the fluid is contaminated, it should be drained, and the system should be flushed and refilled with fresh fluid.
  

5. Hydraulic Warning Lights or Error Codes
Modern machines like the 135SR Kobelco often come equipped with diagnostic systems that trigger warning lights or error codes when a problem arises in the hydraulic system.
Potential Causes:

• Sensor Failure: A faulty sensor can trigger incorrect error codes, leading to unnecessary troubleshooting.
  
• Low Fluid Pressure: Low pressure due to leaks or pump failure can activate warning lights.
  
• System Overload: An overloaded hydraulic system can trigger alarms if the system is forced beyond its capacity.
  

Troubleshooting Steps:

• Consult the Manual: Refer to the operator’s manual to understand the specific error codes or warning lights for your machine.
  
• Check Pressure: Test the hydraulic system’s pressure and ensure it’s within the specified range.
  
• Inspect Sensors: If error codes persist despite resolving the issue, check the hydraulic sensors for faults or miscalibration.
  

Preventative Maintenance for the 135SR Kobelco Hydraulic System
To minimize the chances of encountering hydraulic issues in the future, regular maintenance is crucial. Here are some preventative maintenance tips:

• Regular Fluid Checks: Inspect the hydraulic fluid regularly, looking for signs of contamination, low levels, or discoloration.
  
• Filter Replacement: Replace hydraulic filters at the manufacturer’s recommended intervals to ensure smooth fluid flow and protect the system from contaminants.
  
• Inspect Hoses and Fittings: Conduct visual inspections for any wear, cracks, or leaks in hoses and fittings.
  
• Monitor for Unusual Noise: Any change in hydraulic noise should be investigated immediately to prevent further damage.
  

Conclusion
Hydraulic problems in the Kobelco 135SR can significantly affect the machine’s performance and reliability. By recognizing the symptoms of hydraulic issues and addressing them promptly, operators can extend the life of their equipment and avoid costly repairs. Regular maintenance, including fluid checks, filter replacements, and hose inspections, is essential to keeping the hydraulic system in optimal condition. With a thorough understanding of the hydraulic system and proper troubleshooting techniques, operators can ensure that their 135SR continues to perform efficiently in the field.