How to Remove the Final Drive Cover on the Komatsu PC75UU-2

[MikePhua]

The Komatsu PC75UU-2 is a versatile and reliable mini excavator commonly used for various construction and excavation tasks. Like any piece of heavy equipment, the longevity and performance of the PC75UU-2 depend on regular maintenance and timely repairs. One of the essential components that often require attention is the final drive assembly. In this guide, we will explore the process of removing the final drive cover on the Komatsu PC75UU-2, a critical step when diagnosing or repairing issues with the final drive.
What is the Final Drive on an Excavator?
The final drive is a crucial part of the excavator’s undercarriage system. It’s responsible for transmitting power from the hydraulic motors to the tracks, allowing the machine to move forward, backward, and turn. The final drive consists of several components, including the hydraulic motor, reduction gears, and the final drive cover. Over time, the final drive may require maintenance, either due to wear and tear or specific mechanical issues like leaks or bearing failure.
When working on the final drive, one of the first steps is often removing the final drive cover to inspect the internal components or replace damaged parts. This task can be tricky if you're unfamiliar with the procedure, so following the correct steps is essential for safety and efficiency.
Tools Required for Removing the Final Drive Cover
Before you begin the removal process, ensure you have the following tools:

• Socket Set: Including large sockets for removing bolts.
  
• Wrenches: For loosening and removing the cover bolts.
  
• Impact Wrench: To make the removal of stubborn bolts easier.
  
• Torque Wrench: For tightening bolts to the correct torque specifications during reinstallation.
  
• Pry Bar: To gently loosen the cover if it’s stuck.
  
• Hydraulic Jack: To lift the excavator if needed.
  
• Safety Gear: Gloves, safety glasses, and steel-toed boots for protection.
  

Step-by-Step Guide to Removing the Final Drive Cover
Step 1: Prepare the Excavator
The first step in removing the final drive cover is to prepare the excavator. Ensure the machine is turned off and the hydraulic pressure is relieved. This is essential to prevent any accidental movement of the machine while you’re working on it.

1. Park the Excavator on Level Ground: Ensure the machine is on stable, level ground. This helps avoid any risk of the machine shifting during the repair.
   
2. Engage the Parking Brake: Lock the parking brake to prevent the machine from moving during the removal process.
   
3. Lift the Track: Use a hydraulic jack to lift the track that you will be working on. This will make it easier to access the final drive cover.
   

Step 2: Disconnect the Final Drive Hydraulic Lines
The final drive operates via hydraulic motors, which are powered by the machine’s hydraulic system. To avoid any hydraulic leaks or system damage, disconnect the hydraulic lines that feed into the final drive assembly.

1. Locate the Hydraulic Lines: These lines are typically connected to the final drive motor. You will need to identify the correct lines and disconnect them safely.
   
2. Plug the Lines: Once disconnected, plug the hydraulic lines to prevent any hydraulic fluid from spilling.
   

Step 3: Remove the Track and Sprocket (if necessary)
In some cases, you may need to remove the track or sprocket to access the final drive cover.

1. Track Removal: Using a track removal tool or manual method, remove the track from the sprocket.
   
2. Sprocket Removal: If needed, remove the sprocket by loosening and removing the bolts that secure it in place. This will give you better access to the final drive housing.
   

Step 4: Loosen and Remove the Final Drive Cover Bolts
Once you have clear access to the final drive assembly, the next step is to remove the bolts securing the final drive cover. These bolts can sometimes be difficult to remove due to dirt, grime, and corrosion.

1. Locate the Bolts: The final drive cover will be secured with multiple bolts. Ensure you identify all of them before proceeding.
   
2. Loosen the Bolts: Using a socket or wrench, begin loosening the bolts that hold the cover in place. If any bolts are stuck, you may need to use an impact wrench or penetrating oil to loosen them.
   
3. Remove the Bolts: After loosening the bolts, remove them completely and set them aside for reinstallation.
   

Step 5: Pry Off the Final Drive Cover
Once all the bolts are removed, the final drive cover may still be secured due to dirt or rust. Use a pry bar to gently separate the cover from the housing.

1. Use Even Pressure: Apply gentle, even pressure to avoid damaging the cover or the housing. If the cover does not budge easily, check to make sure all bolts have been removed.
   
2. Lift the Cover: Once loose, carefully lift the cover off the final drive assembly. Be cautious, as the cover may be heavy, depending on the machine’s configuration.
   

Step 6: Inspect the Final Drive Components
With the final drive cover removed, you can now inspect the internal components for wear, damage, or leaks. Some of the key components to inspect include:

• Gears and Bearings: Look for any signs of wear or damage. Excessive wear could indicate issues with lubrication or contamination.
  
• Seals: Check the seals for any signs of leakage, which could lead to oil loss and further damage to the system.
  
• Hydraulic Motor: Inspect the hydraulic motor for any signs of malfunction or leaks.
  

Step 7: Clean and Prepare for Reassembly
Before reassembling the final drive cover, it is important to clean all surfaces thoroughly. Remove any dirt, debris, and old gasket material from the housing and the cover.

1. Clean the Housing: Use a brush and cleaning solvent to remove any accumulated dirt or grime from the final drive housing.
   
2. Inspect Gaskets: Check the gasket that seals the final drive cover to ensure it is in good condition. If damaged, replace it before reassembling.
   

Reassembling the Final Drive Cover
Reassembling the final drive cover is essentially the reverse of the removal process. Here’s how to do it:

1. Position the Final Drive Cover: Place the cleaned final drive cover back into position over the final drive housing.
   
2. Tighten the Bolts: Reinstall the bolts and tighten them to the manufacturer’s specified torque settings using a torque wrench. Ensure the bolts are evenly tightened.
   
3. Reconnect the Hydraulic Lines: Reconnect the hydraulic lines to the final drive motor and ensure they are properly secured.
   
4. Reinstall the Track and Sprocket: If the track or sprocket was removed, reinstall them now, ensuring all bolts are properly tightened.
   

Final Checks and Testing
Once the final drive cover is reassembled, and all components are reconnected, perform a final inspection. Ensure that everything is secure, and check for any hydraulic leaks or unusual noises. Start the engine and operate the excavator at low speed to verify that the final drive is functioning correctly.
Conclusion
Removing and servicing the final drive cover on a Komatsu PC75UU-2 is a critical procedure for diagnosing or repairing issues related to the undercarriage. Whether you're replacing worn-out components or addressing leaks, following the proper steps ensures a safe and efficient repair process. Regular maintenance of the final drive system is essential to the overall health and longevity of the excavator, helping to prevent costly repairs and downtime.