Weak Final Drive Issue on Komatsu PC45MR-1 and Ditch with MX45: Diagnosis and Solutio

[MikePhua]

Introduction
The Komatsu PC45MR-1 mini excavator is a reliable and durable machine used in various construction and landscaping tasks. However, like all heavy machinery, it may experience issues over time. One common problem that owners may face is a weak final drive, which can lead to performance issues and inefficiencies. This article explores the causes of weak final drive problems on the Komatsu PC45MR-1, particularly when working in challenging environments like ditches or when using attachments such as the MX45.
Understanding the Final Drive System
The final drive system in an excavator is responsible for transmitting power from the engine to the tracks, allowing the machine to move. It consists of several key components, including the hydraulic motor, reduction gears, and the drive sprockets. The final drive is crucial for the movement of the excavator, particularly when it’s used in tough terrain or when applying heavy force, such as digging or pushing through dense material.
A weak final drive issue typically manifests as sluggish movement, uneven speed between tracks, or a noticeable decrease in the machine’s ability to move under load.
Symptoms of Weak Final Drive

1. Sluggish or Uneven Movement:
   If the final drive is not operating correctly, you may notice that the excavator moves slower than usual or unevenly, with one track lagging behind the other. This can be particularly noticeable when the machine is in operation on inclines or uneven surfaces.
   Key signs:
   • Uneven movement between the left and right tracks.
     
   • Slower than normal movement, especially under load.
     
   • Difficulty moving the machine forward or backward, particularly when working in ditches or uneven ground.
     
2. Noise or Vibration:
   Another symptom of a weak final drive is abnormal noise or vibration coming from the track drive system. This could indicate that internal components such as gears or bearings are worn out or failing.
   Key signs:
   • Grinding, whining, or clunking noises from the final drive area.
     
   • Unusual vibrations felt in the cabin, especially when the machine is in motion.
     
3. Loss of Track Power:
   A decrease in track power can occur if the final drive is not generating enough torque. This results in the machine struggling to push through tough terrain, like ditches or thick material, leading to decreased productivity and performance.
   Key signs:
   • Loss of ability to push or pull heavy loads.
     
   • Struggles when trying to move through deeper or denser material.
     

Potential Causes of Weak Final Drive

1. Low Hydraulic Fluid or Contaminated Fluid:
   The final drive system relies on hydraulic fluid for proper operation. Low fluid levels or contaminated fluid can lead to inadequate pressure and cause the system to perform poorly. This can lead to slow response times or even total failure of the drive motor.
   Possible causes:
   • Leaks in hydraulic hoses or seals.
     
   • Use of poor-quality or contaminated hydraulic fluid.
     
   • Infrequent fluid changes leading to build-up of debris or contaminants.
     
2. Worn Hydraulic Motor:
   A worn or damaged hydraulic motor can cause the final drive to become weak. Over time, components such as seals and bearings in the hydraulic motor can wear out, reducing the motor’s ability to generate sufficient power to move the tracks efficiently.
   Possible causes:
   • Wear and tear due to prolonged use or improper maintenance.
     
   • Lack of lubrication causing internal components to seize or malfunction.
     
3. Damaged Reduction Gears:
   The reduction gears in the final drive reduce the rotational speed of the hydraulic motor and increase torque to the tracks. If these gears become damaged or worn, they may not deliver the proper amount of power to the tracks, leading to weak or uneven movement.
   Possible causes:
   • Improper gear meshing due to lack of maintenance.
     
   • Overload or excessive stress placed on the final drive system.
     
4. Contaminated or Damaged Bearings:
   Bearings within the final drive system help reduce friction and allow smooth operation. If the bearings become contaminated or damaged, they can cause friction, heat build-up, and further damage to the final drive.
   Possible causes:
   • Dirt and debris entering the system through damaged seals.
     
   • Lack of proper lubrication leading to premature bearing wear.
     
5. Track Tension Issues:
   Incorrect track tension can put excess strain on the final drive, especially when the excavator is working in rough terrain like ditches. If the tracks are too tight or too loose, it can affect the performance of the final drive and contribute to uneven movement or power loss.
   Possible causes:
   • Incorrect track adjustment.
     
   • Tracks that are worn or have uneven wear patterns.
     

Diagnosing Final Drive Problems

1. Check Hydraulic Fluid Levels:
   Inspect the hydraulic fluid levels regularly and ensure they are within the recommended range. If fluid levels are low, check for leaks in hoses, seals, or the hydraulic pump. Replace contaminated fluid and use high-quality hydraulic fluid to maintain proper system performance.
   
2. Inspect the Hydraulic Motor:
   Perform a visual inspection of the hydraulic motor for any signs of wear, leaks, or damage. Listen for unusual noises when the machine is in operation, which could indicate issues with the motor. If the motor is found to be faulty, it may need to be rebuilt or replaced.
   
3. Examine the Reduction Gears:
   Inspect the reduction gears for any signs of wear or damage. You can check for excessive play or noise while the machine is running. If necessary, replace the gears and ensure proper lubrication.
   
4. Check for Bearing Damage:
   Inspect the bearings in the final drive for any signs of wear or contamination. If bearings are damaged, they should be replaced to prevent further damage to the system.
   
5. Adjust Track Tension:
   Ensure that the track tension is properly adjusted. If the tracks are too tight or too loose, they can place unnecessary strain on the final drive system. Adjusting the track tension to the manufacturer’s recommended settings can improve final drive performance.
   

Solutions for Weak Final Drive Issues

1. Replace Worn or Damaged Components:
   If diagnostics reveal that certain components, such as the hydraulic motor, reduction gears, or bearings, are worn out, they should be replaced immediately to restore the final drive’s power.
   
2. Maintain Proper Fluid Levels and Quality:
   Regularly check and maintain the hydraulic fluid levels. Replace old or contaminated fluid and clean the system to ensure smooth operation.
   
3. Regular Maintenance:
   Perform regular maintenance on the final drive system, including inspecting components for wear, checking fluid levels, and adjusting the track tension. A well-maintained system is less likely to suffer from performance issues.
   
4. Track Tension Adjustment:
   Make sure that track tension is regularly checked and adjusted according to manufacturer guidelines. Proper tension ensures that the final drive is not under excessive stress.
   

Conclusion
A weak final drive on the Komatsu PC45MR-1 can significantly impact the machine’s performance, especially when working in demanding environments like ditches. Diagnosing the cause of the problem involves checking hydraulic fluid levels, inspecting the hydraulic motor, and examining key components like the reduction gears and bearings. Regular maintenance, proper fluid care, and ensuring the correct track tension are crucial in preventing final drive issues. By addressing the problem early, operators can extend the lifespan of their machine and improve its performance.