Troubleshooting Komatsu PC35 MR-2 Swing and Blade Issues

[MikePhua]

The Komatsu PC35 MR-2 is a popular compact excavator, known for its maneuverability and versatility in tight spaces. However, like all machinery, it can develop issues over time, particularly with its swing function and blade operation. In this article, we will explore some common causes of swing and blade malfunctions in the PC35 MR-2, their potential solutions, and helpful maintenance tips to keep this machine running efficiently.
Overview of the Komatsu PC35 MR-2
The Komatsu PC35 MR-2 is part of Komatsu’s lineup of mini-excavators designed for urban construction, landscaping, and smaller excavation tasks. This machine is valued for its ability to operate in confined areas, offering a balance between power and compact size. The PC35 MR-2 is equipped with a swing function, which allows the boom to rotate, and a blade, which is essential for levelling and stabilizing the machine. These two features are vital for effective operation and are often the source of troubleshooting when problems arise.
Understanding the Swing Function on the PC35 MR-2
The swing function of the PC35 MR-2 allows the operator to rotate the boom and bucket to the left or right, providing flexibility in the positioning of the bucket for digging, dumping, or lifting operations. The swing motor powers this movement, and if there are issues with it, it can lead to a loss of rotation, erratic swinging, or complete failure to rotate.
Common Causes of Swing Issues

1. Hydraulic System Problems
   The swing motor on the PC35 MR-2 is powered by hydraulic fluid. If there is a problem with the hydraulic system, such as low fluid levels, contaminated fluid, or a hydraulic leak, the swing function can be affected. Low hydraulic fluid can result in insufficient pressure to operate the swing motor, leading to weak or intermittent movement.
   • Solution: Ensure that the hydraulic fluid is at the correct level and free from contamination. Check for any visible leaks around the hydraulic lines and fittings, especially near the swing motor. If the fluid is dirty or degraded, it may need to be replaced.
     
2. Faulty Swing Motor or Gearbox
   The swing motor is responsible for providing the power to rotate the excavator’s upper structure. Over time, the motor or its associated gearbox can wear out, leading to malfunctioning swing action. Symptoms of a faulty swing motor include the swing arm freezing or operating slowly.
   • Solution: Inspect the swing motor for signs of damage or wear. If the motor is faulty, it may need to be replaced or rebuilt. Ensure that all gear connections are tight and free from wear that could impact performance.
     
3. Electrical or Control Valve Issues
   The swing function of the PC35 MR-2 is controlled electronically, with a control valve directing hydraulic flow to the swing motor. Any issues with the electrical system or control valve, such as wiring problems or malfunctioning sensors, can disrupt the smooth operation of the swing.
   • Solution: Check the wiring and connectors for any loose or corroded connections. Test the control valve’s electrical components to ensure proper operation. If the valve is malfunctioning, it may need to be replaced.
     
4. Internal Hydraulic Component Failures
   Internal components of the swing system, such as pumps or valves, can fail due to wear and tear or improper maintenance. This can lead to a complete loss of swing function or jerky, erratic movement.
   • Solution: Have the hydraulic system thoroughly inspected by a qualified technician. If any internal components are damaged, they should be replaced with OEM parts to restore optimal swing function.
     

Troubleshooting the Blade Issues
The blade of the Komatsu PC35 MR-2 is essential for stabilizing the machine and leveling the ground. It is powered by the same hydraulic system as the swing, but it operates separately with its own control. Blade issues can manifest in various ways, including poor lifting, inability to adjust, or a non-responsive blade.
Common Causes of Blade Malfunctions

1. Hydraulic Fluid Issues
   As with the swing function, hydraulic fluid problems are a common cause of blade issues. Low fluid levels, contamination, or air in the hydraulic system can lead to reduced blade operation.
   • Solution: Ensure that the hydraulic fluid is clean and at the appropriate level. If the fluid appears cloudy or contaminated, perform a hydraulic fluid change and replace any worn filters.
     
2. Faulty Blade Cylinder or Valve
   The blade’s movement is powered by a hydraulic cylinder, which can wear out over time, especially if the machine is used frequently. Additionally, the valve controlling the blade’s operation can develop issues, such as sticking or leaking.
   • Solution: Inspect the blade cylinder for any signs of leaking or damage. If the cylinder is faulty, it should be replaced or rebuilt. Check the valve and hydraulic lines for blockages, leaks, or damage that may be hindering blade operation.
     
3. Control System Problems
   The blade control is often linked to a joystick or separate lever. If the controls are not functioning properly, it can affect the ability to raise, lower, or adjust the blade. This can be caused by faulty switches, wiring, or a malfunctioning control module.
   • Solution: Test the blade controls to ensure they are responding as expected. Inspect the wiring and switches for any faults. If the issue is electronic, it may require recalibration or replacement of the control system components.
     
4. Mechanical Obstructions
   Sometimes, mechanical obstructions such as debris or bent components can prevent the blade from moving smoothly. This is especially true if the machine has been operating in rough conditions or on uneven terrain.
   • Solution: Perform a visual inspection of the blade assembly and surrounding components for any obstructions. Clean any dirt or debris that may be interfering with the blade’s operation. If components are bent or damaged, they may need to be straightened or replaced.
     

Diagnostic Steps to Resolve the Issue
If you are encountering issues with the swing or blade on your Komatsu PC35 MR-2, follow these steps to diagnose and resolve the problem:

1. Check Hydraulic Fluid
   Verify that the hydraulic fluid is at the proper level and free of contaminants. Low or dirty fluid can cause issues with both the swing and blade functions.
   
2. Inspect for Leaks
   Examine the hydraulic lines, fittings, and cylinders for signs of leaks or wear. A small leak can lead to a significant loss of performance in these systems.
   
3. Test the Control System
   Ensure that the control valves, electrical components, and wiring are functioning properly. Faulty wiring or sensors can cause intermittent issues that are difficult to detect without proper testing.
   
4. Evaluate Mechanical Components
   Look for any mechanical damage to the swing motor, gearbox, blade cylinder, or other parts. Replace any worn or damaged components to restore functionality.
   

Preventative Maintenance Tips
To prevent future issues with the swing and blade systems on your Komatsu PC35 MR-2, consider these maintenance tips:

• Regularly check and replace hydraulic fluid and filters to ensure proper operation.
  
• Inspect hydraulic lines and seals for signs of wear or damage.
  
• Lubricate moving parts and components to reduce friction and wear.
  
• Periodically test the control systems and recalibrate them as needed.
  
• Clean the machine thoroughly after each use, especially after working in muddy or rough conditions.
  

Conclusion
The Komatsu PC35 MR-2 is a reliable and versatile machine that can face a range of issues, particularly with its swing and blade functions. By understanding the potential causes of these problems, such as hydraulic fluid issues, faulty components, or control system malfunctions, operators can take the necessary steps to diagnose and repair the machine. Regular maintenance and attention to the hydraulic system are key to ensuring the longevity and optimal performance of the PC35 MR-2.