Kobelco SK120 MKV Excavator: Common Issues and Solutions

[MikePhua]

The Kobelco SK120 MKV is a popular mid-sized hydraulic excavator known for its reliability and performance on construction and demolition sites. However, like any piece of heavy machinery, it is susceptible to certain mechanical issues that operators and technicians may encounter over time. This article covers some common problems with the Kobelco SK120 MKV and provides insight into diagnosing and resolving them.
1. Hydraulic System Problems
One of the primary concerns with the Kobelco SK120 MKV is hydraulic system failure, which can lead to a loss of power, erratic movements, or complete system shutdowns. Common causes of hydraulic problems include:

• Hydraulic Fluid Contamination: Contaminants in the hydraulic fluid can clog filters, restrict flow, and damage internal components like pumps and valves.
  
• Leaks: Hydraulic leaks, especially around hoses and seals, can cause a drop in fluid levels, leading to system failures.
  
• Worn-out Hydraulic Components: Over time, parts like pumps, motors, and valves can wear out due to prolonged usage, leading to poor performance.
  

Solutions:

• Regularly inspect the hydraulic fluid for contamination and change it as needed.
  
• Replace damaged or worn-out hydraulic components and seals.
  
• Check for leaks in hoses, cylinders, and fittings, repairing or replacing them as necessary.
  

2. Engine Performance Issues
The engine is the heart of any excavator, and problems with it can significantly affect the overall performance of the SK120 MKV. Common engine-related issues include:

• Starting Difficulties: Hard starting or failure to start can be caused by fuel system issues, dead batteries, or electrical faults.
  
• Low Power Output: Loss of engine power may result from clogged air filters, faulty injectors, or fuel system problems.
  
• Overheating: Overheating can occur due to radiator issues, low coolant levels, or a malfunctioning fan.
  

Solutions:

• Perform regular checks and maintenance on the fuel system, including cleaning or replacing fuel filters and inspecting the fuel injectors.
  
• Ensure the air filter is clean and replace it regularly.
  
• Check coolant levels and ensure the radiator and fan are functioning properly.
  

3. Track and Undercarriage Issues
The undercarriage and tracks are critical to the performance of the SK120 MKV, and issues in these areas can lead to costly downtime. Common problems include:

• Track Wear: Tracks may become worn, leading to reduced traction and efficiency, especially in harsh working conditions.
  
• Track Tension Problems: Improper track tension can cause excessive wear, damage to the sprockets, or even track derailment.
  
• Undercarriage Damage: Regular wear and tear on components like rollers, idlers, and sprockets can result in reduced mobility and performance.
  

Solutions:

• Regularly check the track tension and adjust it according to manufacturer specifications.
  
• Inspect the undercarriage for excessive wear and replace any damaged components.
  
• Replace worn tracks promptly to prevent further damage to the drive system.
  

4. Electrical and Sensor Malfunctions
Electrical issues can cause a variety of problems in the Kobelco SK120 MKV, including:

• Faulty Sensors: Sensors that monitor hydraulic pressure, temperature, and fuel levels may fail, leading to inaccurate readings or operational issues.
  
• Electrical Short Circuits: Short circuits in wiring or malfunctioning fuses can disrupt power to essential components.
  
• Display Panel Problems: The display panel may show error codes or fail to function, making it difficult for operators to monitor the machine’s status.
  

Solutions:

• Regularly inspect wiring and connectors for signs of wear or corrosion.
  
• Test sensors to ensure they are providing accurate data and replace any faulty ones.
  
• Check fuses and replace any blown fuses to ensure proper electrical functioning.
  

5. Final Drive and Swing Motor Issues
Problems with the final drive or swing motor can severely impact the movement and operation of the Kobelco SK120 MKV. Common issues include:

• Final Drive Failure: This can occur due to excessive wear or lubrication issues, causing the machine to lose power or even cease movement.
  
• Swing Motor Problems: If the swing motor fails, the excavator may have difficulty turning or positioning itself.
  

Solutions:

• Regularly check the final drive for proper lubrication and replace the oil as recommended by the manufacturer.
  
• Inspect the swing motor for damage or signs of excessive wear and replace any faulty components.
  
• Ensure that the swing motor and final drive are properly lubricated to prevent premature failure.
  

6. Preventative Maintenance and Care
To keep the Kobelco SK120 MKV in top condition, it’s important to perform regular maintenance and inspections. Here are a few tips:

• Follow the manufacturer’s recommended maintenance schedule for oil changes, filter replacements, and fluid checks.
  
• Keep the machine clean and free of debris, especially in critical areas like the engine compartment, radiator, and hydraulic system.
  
• Inspect the undercarriage and tracks frequently to catch any signs of wear early and avoid costly repairs.
  
• Address any warning lights, error codes, or unusual sounds promptly to prevent further damage.
  

7. Conclusion
The Kobelco SK120 MKV is a powerful and reliable excavator, but like any heavy machinery, it requires regular maintenance and attention to detail. By understanding the common issues it faces and taking proactive steps to address them, you can ensure that your SK120 MKV remains in peak condition and continues to deliver exceptional performance for years to come. Regular inspections, proper lubrication, and timely repairs will go a long way in minimizing downtime and extending the life of your equipment.