Handling Broken Bolts When Removing Track Rollers

[MikePhua]

When working with heavy machinery, especially tracked equipment like bulldozers, excavators, and other construction machines, maintenance and repairs are inevitable. One of the common issues that operators and technicians face is when bolts break off while attempting to remove track rollers. This can cause significant delays, increase repair costs, and sometimes even halt operations, making it essential to understand the causes, challenges, and solutions for such situations.
Understanding the Problem
Track rollers are a crucial part of a tracked machine’s undercarriage. These rollers help support the weight of the equipment while enabling the machine to move efficiently across various terrains. The removal of track rollers is often required for regular maintenance, such as replacing worn rollers or conducting more extensive repairs to the undercarriage system.
However, one of the most frustrating and time-consuming problems that can arise during the removal process is when bolts break off inside the threads of the frame. This can happen for a variety of reasons, ranging from corrosion to over-tightening, and can lead to substantial difficulties in disassembling the machine.
Causes of Broken Bolts
There are several reasons why bolts can break off when removing track rollers. Understanding these causes can help prevent the issue from occurring in the first place.

1. Corrosion: Over time, the bolts that secure the track rollers can become corroded due to exposure to moisture, dirt, and other environmental factors. Corrosion can weaken the integrity of the bolt, making it more susceptible to breaking when torque is applied during removal.
   
2. Over-tightening: If the bolts have been over-tightened during previous maintenance, they may become brittle and prone to snapping when torque is applied during the removal process.
   
3. Wear and Tear: The natural wear and tear of heavy equipment, particularly when it operates in tough environments such as construction sites or mining areas, can weaken the bolts, making them more likely to break during disassembly.
   
4. Improper Tools or Techniques: Using the wrong tools or applying uneven force can put excessive strain on the bolts, causing them to fail. It's important to use the correct wrenches, impact tools, and torque settings to ensure the bolts come off without breaking.
   
5. Old Age of Equipment: Older equipment often suffers from the effects of prolonged use, and its components may be more fragile, making them more prone to issues like broken bolts.
   

Solutions for Broken Bolts
While a broken bolt can seem like a daunting challenge, there are several methods and techniques available for removing broken bolts from track rollers. These approaches can help save time and avoid causing further damage to the equipment.
1. Use of Bolt Extractors
Bolt extractors are specialized tools designed to remove broken or stuck bolts. These tools are widely used in the automotive and construction industries to tackle this specific problem. They are available in different sizes and types, such as manual, impact, or pneumatic versions, depending on the severity of the break.

• How They Work: Bolt extractors feature a left-handed spiral design that grips onto the broken bolt when rotated counterclockwise. Once in place, applying steady force can allow the extractor to twist the bolt out of its threaded hole.
  
• When to Use: If the bolt head is intact but the shaft is broken, bolt extractors can be a highly effective solution.
  

2. Drilling Out the Bolt
If the bolt extractor fails or the bolt is severely damaged, drilling out the broken bolt may be the next step. This method involves carefully drilling into the center of the broken bolt to remove it from the threaded hole.

• Tools Required: You’ll need a center punch, a drill bit (preferably a cobalt or carbide drill bit for hardened steel), and a drill press or hand drill. A tapping kit may also be necessary if the threads inside the hole are damaged.
  
• Steps:
  
  1. Center Punch: Use a center punch to mark the exact center of the broken bolt.
     
  2. Drill: Using a small drill bit, begin drilling into the bolt’s center. Gradually increase the size of the drill bits to match the size of the bolt.
     
  3. Extract the Bolt: Once you’ve drilled deep enough, the bolt should loosen, and you can use pliers or a similar tool to extract the remaining piece.
     
  4. Clean and Repair the Threads: If the threads are damaged, use a tap to clean or re-thread the hole.
     

3. Heat Application
Another technique for removing broken bolts is applying heat to the surrounding area. The application of heat causes the metal to expand, which can help break any rust or corrosion holding the bolt in place.

• Tools Required: A torch or heat gun can be used for this process.
  
• How It Works: Heat the surrounding area of the bolt and the bolt itself. This expansion can loosen the bolt enough to make removal easier. This method works particularly well if the bolt has been in place for a long time and is affected by corrosion.
  

4. Cutting the Bolt
In some cases, cutting the bolt may be necessary, particularly if there is no easy way to access the bolt or if the threads are beyond repair.

• Tools Required: A cutting torch or grinder can be used to cut the bolt. Care must be taken not to damage the surrounding area.
  
• How It Works: Use the cutting tool to slice through the bolt, making it easier to remove in pieces. Once the majority of the bolt is removed, you can drill out the remaining portion or use a punch to dislodge it.
  

5. Thread Repair
Once the bolt is removed, it’s essential to repair the threads in the hole to ensure the new bolt fits securely. HeliCoil or Time-Sert thread inserts are commonly used to restore damaged threads. These inserts are inserted into the hole, and the new bolt threads into the insert, providing a durable repair.
Prevention Tips
To avoid broken bolts during future track roller maintenance, consider the following preventive measures:

• Regular Maintenance: Regularly inspect the bolts for signs of wear, corrosion, or damage. Preventive maintenance can help catch issues before they lead to bolt breakage.
  
• Lubrication: Apply a lubricant or anti-seize compound to the bolts during reassembly. This reduces friction and makes future removal easier.
  
• Proper Tightening Techniques: Always follow the manufacturer's torque specifications when tightening bolts to prevent over-tightening, which can cause damage.
  
• Use of Anti-Corrosion Coatings: For machines working in harsh environments, such as wet or salty conditions, use bolts that are resistant to corrosion or apply anti-corrosion coatings.
  

Conclusion
Dealing with broken bolts while removing track rollers is a common but frustrating issue in heavy machinery maintenance. Understanding the causes and applying the appropriate solutions can save both time and money while ensuring the continued reliability of the equipment. Regular maintenance, proper tools, and a careful approach to disassembly can significantly reduce the likelihood of encountering broken bolts in the future.