Hitachi EX120 Excavator Bucket Repair

[MikePhua]

Introduction
The Hitachi EX120 series excavators have long been recognized for their durability and versatility in various construction and excavation tasks. However, like all heavy machinery, they are subject to wear and tear, especially in high-stress components such as the bucket. A common issue faced by operators is the tearing of the bucket's sidewalls, often exacerbated by improper usage, such as using the bucket teeth to break concrete.
Understanding the Problem
The bucket of an excavator is designed primarily for digging and material handling. Using the bucket teeth to break concrete or other hard materials can impose excessive stress on the bucket's structure, leading to cracks and tears. This misuse can also damage the bucket's pins, bushings, and support plates, which are critical for the bucket's operation. Operators have reported that such practices can lead to torsional loads on the pin supports, causing cracks at the pin plate welds.
Repairing Torn Bucket Sidewalls
When faced with a torn bucket sidewall, timely and effective repair is essential to restore the bucket's functionality and prevent further damage. Here's a step-by-step guide to repairing a torn bucket sidewall:

1. Assessment: Begin by thoroughly inspecting the bucket to assess the extent of the damage. Look for cracks, tears, or any signs of structural weakness.
   
2. Preparation: Clean the damaged area to remove any dirt, debris, or rust. This ensures a clean surface for welding and helps achieve a strong bond.
   
3. Welding: Use a suitable welding technique to repair the tear. For instance, some operators have successfully used 7018 welding rods on AC machines, though results may vary depending on the specific equipment used.
   
4. Reinforcement: After welding, consider adding reinforcement plates to the repaired area to distribute the stress more evenly and enhance the bucket's strength.
   
5. Inspection: Finally, inspect the repair to ensure it is solid and free from defects. Regularly monitor the repaired area during subsequent operations to catch any potential issues early.
   

Preventing Future Damage
To prevent future damage to the bucket, operators should adhere to best practices:

• Proper Usage: Avoid using the bucket teeth to break concrete or other hard materials. Instead, use appropriate tools such as hydraulic breakers designed for such tasks.
  
• Regular Maintenance: Perform regular inspections and maintenance on the bucket and its components, including pins, bushings, and support plates.
  
• Training: Ensure that all operators are adequately trained in the proper use and maintenance of the excavator and its attachments.
  

Conclusion
The Hitachi EX120 excavator is a robust machine capable of handling various tasks. However, like all heavy equipment, it requires proper care and maintenance to ensure longevity and optimal performance. By understanding the causes of bucket damage and implementing preventive measures, operators can extend the life of their equipment and reduce the likelihood of costly repairs.