Removing a Link from the Track Chain on a Caterpillar 977H

[MikePhua]

The Caterpillar 977H is a versatile crawler loader, widely recognized for its durability and efficiency in demanding tasks such as excavation, earthmoving, and material handling. One of the key features of the 977H is its track system, which enables it to operate smoothly over rough terrain. However, over time, the track system may require maintenance or adjustments. One common task is the removal of a link from the track chain, which can be necessary due to wear, damage, or when replacing components like sprockets or track shoes. In this article, we'll walk through the process of removing a link from the track chain on a Caterpillar 977H, outlining key steps and best practices to ensure a smooth procedure.
Understanding the Track System on the 977H
The track system on the Caterpillar 977H is composed of several interconnected links that make up the track chain. These links are the fundamental components responsible for the machine’s mobility and traction. The track chain consists of multiple parts, including:

• Track links: The main components that form the chain.
  
• Pins: The cylindrical components that connect the track links.
  
• Bushings: These allow the links to pivot and rotate without excessive friction.
  
• Sprockets: Teeth that engage with the track chain to propel the machine.
  
• Track rollers and idlers: Components that support the track chain and guide it along the machine’s frame.
  

A typical reason for removing a link involves addressing wear on the track, replacing damaged components, or adjusting the track tension. It’s important to approach this task with the right tools and knowledge, as improper removal or reinstallation of the links can cause further damage to the track system.
Preparing for Track Link Removal
Before removing a link from the track chain, proper preparation is essential. The following steps ensure a safe and efficient process:

1. Safety Precautions:
   • Ensure the machine is turned off and the engine is cool.
     
   • Use safety gear, including gloves, safety glasses, and steel-toed boots.
     
   • Jack up the machine to relieve pressure from the tracks, if necessary, and secure it with appropriate supports.
     
2. Inspect the Track Condition:
   • Assess the overall condition of the track system, including links, pins, bushings, and rollers. Make a note of any additional repairs or replacements that may be needed after removing the link.
     
3. Locate the Master Pin:
   • The master pin is the pin that holds the track links together. This pin is often larger or different in shape than the others and is the primary point of removal.
     

Tools and Equipment Needed
To remove a link from the track chain, you will need the following tools:

• Track pin removal tool: This specialized tool is designed to press out or pull out the track pins.
  
• Hydraulic press or hammer: A hydraulic press can be used for more controlled removal, while a hammer may be used with a punch for manual force.
  
• Track block or support blocks: Used to support the track while you work.
  
• Wrenches and sockets: For loosening nuts or bolts if applicable.
  
• Measuring tape: To measure the chain length and ensure proper tension.
  

Step-by-Step Process for Removing a Link
1. Loosen Track Tension
Before attempting to remove any links, it’s crucial to relieve tension from the track. To do this:

• Use the track adjuster to reduce tension on the track. Most Caterpillar machines like the 977H have an adjuster bolt or hydraulic cylinder that can be used to loosen or tighten the track.
  
• Check the tension by pressing down on the track to ensure it’s loose enough for the removal process.
  

2. Locate and Remove the Master Pin
The master pin is typically located at the end of the track chain and holds the links together. Removing this pin is crucial for separating the links. To remove the master pin:

• Use a track pin removal tool: This tool is designed to apply enough pressure to push out the master pin. If the pin is stubborn or rusted in place, you may need to use a hammer and punch to tap it out.
  
• Inspect the master pin: Once removed, inspect the master pin for wear. In some cases, you may need to replace it if it’s damaged.
  

3. Remove the Desired Track Link
Once the master pin is removed, the track chain can be separated, and the specific link can be taken out.

• Carefully separate the links: Once the master pin is out, gently pry the links apart using the removal tool. Be cautious to avoid damaging other components in the process.
  
• Inspect other parts: While removing a link, it’s a good idea to inspect the surrounding pins, bushings, and rollers for wear or damage. You may need to replace them as part of the maintenance process.
  

4. Reinstall the Track Link
After the necessary track link has been removed and replaced, it’s important to reinstall the track link correctly. To do this:

• Insert a new pin or reuse the old one: Insert a new pin or reinsert the original master pin, ensuring it’s seated properly.
  
• Ensure proper alignment: Align the track links carefully before securing the pin. Misalignment can cause premature wear and failure.
  
• Tighten the pin: Use the track pin tool to press the pin back into place. Make sure it’s tightly secured.
  

5. Re-tension the Track
After the link has been removed or replaced, and the pin is secured, it’s essential to re-tension the track properly:

• Use the track adjuster to set the proper tension according to the manufacturer’s specifications.
  
• Ensure that the track is properly aligned and is not too tight or too loose.
  

Common Challenges and Troubleshooting

• Stubborn Pins: In some cases, the track pins can become rusted or frozen in place, making removal difficult. If this happens, consider using a penetrating lubricant or heat (carefully applied) to loosen the pin.
  
• Uneven Track Wear: If the track is excessively worn or the machine’s components are misaligned, it may cause uneven tension and additional wear. Consider checking the track rollers, sprockets, and idlers for wear as well.
  
• Alignment Issues: After reinstalling the track link, always verify the alignment of the track chain. Misalignment can cause premature wear, especially in the sprockets.
  

Conclusion
Removing a link from the track chain of a Caterpillar 977H is a manageable task when performed with the right tools and careful attention to detail. Proper preparation and following the correct steps for pin removal, link separation, and track reassembly are critical to the success of the procedure. Regular inspection and maintenance of the track system will extend the life of your machine and ensure optimal performance. If you encounter persistent issues, consulting with a professional technician may be necessary to avoid further damage. By understanding the importance of proper track care and following these guidelines, you can keep your Caterpillar 977H operating efficiently and reliably for many years.