Replacing the Lower Turntable Seal on a John Deere 160LC

[MikePhua]

The John Deere 160LC is a powerful and reliable hydraulic excavator that finds its place in a variety of construction, excavation, and heavy-duty tasks. As with all equipment, regular maintenance and repairs are vital for longevity and optimal performance. One common issue that may arise in such machines is the wear and failure of the lower turntable seal, which can lead to fluid leaks and operational inefficiencies. Understanding how to replace this seal is crucial for maintaining the integrity of the machine's swing system.
Understanding the Role of the Lower Turntable Seal
The lower turntable seal is located at the base of the excavator where the upper and lower portions of the machine rotate. This seal plays a key role in preventing hydraulic fluid leaks between the upper and lower turntable assemblies. It ensures that the hydraulic fluid used for the swing mechanism stays contained, preventing contamination and loss of power.
The turntable, which connects the undercarriage to the upper structure of the excavator, requires a high degree of precision and stability to allow smooth and consistent rotation. Over time, exposure to heavy loads, dust, and dirt can cause wear on the lower turntable seal, leading to leaks and reduced efficiency.
Signs of a Faulty Lower Turntable Seal
When the lower turntable seal begins to fail, the most noticeable sign is the leakage of hydraulic fluid around the base of the machine. This can lead to several issues:

• Hydraulic fluid loss: If fluid is leaking, the excavator's hydraulic system may lose pressure, affecting the performance of the swing motor and overall movement.
  
• Reduced swing performance: Leaks can lead to erratic or slow rotation of the upper structure.
  
• Increased contamination: Dust and dirt can enter the hydraulic system through the gaps in the seal, causing additional wear on other components.
  
• Visible pooling of hydraulic fluid: You may notice fluid pooling around the lower turntable area, especially after the machine has been stationary for some time.
  

Replacing the Lower Turntable Seal: Step-by-Step Guide
Replacing the lower turntable seal on a John Deere 160LC requires attention to detail, proper tools, and a basic understanding of the machine's hydraulic and mechanical systems. Below is a comprehensive guide to replacing this seal.
Step 1: Safety Precautions
Before beginning any maintenance work, it is essential to take safety precautions. These include:

• Shut down the machine: Turn off the engine and let it cool down if it has been running.
  
• Ensure stability: Secure the excavator on level ground. Use appropriate support or jacks to prevent the machine from shifting.
  
• Disconnect the battery: Disconnecting the battery helps prevent accidental electrical shorts or system malfunctions.
  
• Drain hydraulic fluid: Before removing any components, drain the hydraulic system to avoid any fluid spills during the seal replacement.
  

Step 2: Removing the Turntable Assembly
Once safety precautions are in place, the next step is to remove the turntable assembly:

• Lift the upper structure: Using a lifting device or crane, carefully lift the upper part of the excavator, ensuring that it is supported securely.
  
• Disconnect hydraulic lines: Disconnect any hydraulic lines connected to the swing motor and other components that are part of the turntable assembly.
  
• Remove bolts and fasteners: Use an impact wrench or appropriate tools to remove the bolts securing the turntable to the lower portion of the machine. Keep track of the bolts for reassembly.
  
• Separate the turntable: Once the bolts and fasteners are removed, carefully separate the upper and lower turntable portions. This step requires precision to prevent any damage to the machine’s frame.
  

Step 3: Inspecting the Turntable and Seal
With the turntable removed, take this opportunity to inspect both the seal area and the surrounding components:

• Inspect the turntable surface: Check the surface of the turntable for any damage, cracks, or excessive wear that could prevent a proper seal from being formed.
  
• Clean the sealing area: Use a clean cloth or brush to remove any dirt, debris, or old sealant from the sealing area. Ensure that no contaminants are left behind that could compromise the new seal.
  
• Check the condition of the hydraulic components: Examine the hydraulic pump and swing motor to ensure they are functioning properly and free from contamination.
  

Step 4: Replacing the Seal
Once the area is cleaned and inspected, it’s time to replace the lower turntable seal:

• Remove the old seal: Carefully remove the old, worn seal from its housing. Use a seal puller or appropriate tools to avoid damaging the housing area.
  
• Install the new seal: Place the new seal into the housing and ensure that it fits securely. Be sure to follow the manufacturer’s instructions regarding the correct orientation and installation of the seal.
  
• Lubricate the seal: Before installing the new seal, apply a thin layer of hydraulic fluid to the seal’s surface to ensure smooth operation and prevent damage during the initial startup.
  

Step 5: Reassembling the Turntable
After the new seal is installed, the next step is to reassemble the turntable:

• Align the upper and lower portions: Carefully align the turntable components, ensuring that the new seal is properly positioned and the hydraulic lines are correctly connected.
  
• Reattach bolts and fasteners: Reinstall the bolts and fasteners that secure the upper and lower turntable sections together. Tighten them to the specified torque values.
  
• Reconnect hydraulic lines: Reconnect the hydraulic lines to the swing motor and other components that were disconnected earlier.
  
• Test the system: Once reassembled, check the hydraulic fluid levels and test the system by operating the swing function. Ensure that there are no leaks, and verify that the turntable operates smoothly.
  

Final Considerations and Maintenance Tips
Replacing the lower turntable seal on a John Deere 160LC is a relatively straightforward task for those with mechanical expertise, but it requires attention to detail to avoid damage and ensure proper operation. After replacement, regular maintenance is key to prolonging the life of the machine:

• Regularly check for leaks: Periodically inspect the lower turntable seal and surrounding areas for any signs of leakage or wear.
  
• Keep hydraulic fluid clean: Regularly change the hydraulic fluid and filters to prevent contamination from causing damage to the new seal.
  
• Perform routine checks: Conduct regular maintenance on the swing motor, hydraulic lines, and turntable components to ensure that everything remains in optimal condition.
  

By following these steps and taking the necessary precautions, operators can maintain the integrity of the John Deere 160LC and avoid costly repairs in the future.