Front Idler Pillow Block Wear on Hitachi EX 120-2: Troubleshooting and Solutions

[MikePhua]

The Hitachi EX 120-2 is a popular model in the construction and excavation industry, known for its versatility, power, and durability. However, like any piece of heavy equipment, the EX 120-2 is prone to wear and tear over time, especially in the undercarriage components. One common issue that operators face with this model is the wear of the front idler pillow block, a critical part of the machine's track system. This article explores the causes of front idler pillow block wear, its impact on machine performance, and solutions to extend the life of this component.
Understanding the Front Idler Pillow Block
The front idler pillow block is a key component in the undercarriage of track-type excavators like the Hitachi EX 120-2. The pillow block serves as the housing for the axle that supports the front idler wheel. This component helps to guide the tracks and maintain proper track tension, which is essential for the machine's stability and performance.
The pillow block is subjected to constant pressure and movement as the tracks rotate and move over various surfaces. Over time, friction, dirt, and load-bearing stresses can cause the pillow block to wear, leading to a range of potential issues, including reduced track tension, excessive wear on the idler wheels, and a loss of overall track system performance.
Causes of Front Idler Pillow Block Wear
Several factors can contribute to the wear of the front idler pillow block on the Hitachi EX 120-2:

1. Improper Track Tension: If the tracks are too loose or too tight, the added stress can lead to accelerated wear on the idler components. Over-tightening the tracks can cause unnecessary friction, while loose tracks can result in excessive movement and strain on the pillow block.
   
2. Poor Lubrication: Lack of proper lubrication on the idler axle can cause increased friction between the moving parts, leading to premature wear on the pillow block. It’s essential to ensure that the lubrication system is functioning correctly and that the pillow block is regularly serviced.
   
3. Contaminants in the Track System: Dirt, mud, and debris can enter the track system and contaminate the pillow block and its housing. Over time, these contaminants can cause abrasive wear, which damages the pillow block’s surface and can result in misalignment or loosening of the components.
   
4. Heavy Usage and High Loads: Excavators that operate in tough conditions, such as on rough terrain or when lifting heavy loads, put additional stress on the undercarriage. The front idler pillow block may wear more quickly in such situations, especially if the machine is used frequently for heavy digging, grading, or lifting operations.
   
5. Improper Alignment: If the front idler is misaligned, it can cause uneven wear on the pillow block and other track components. Misalignment can be caused by improper installation, damage to the undercarriage, or wear on other parts that affect the idler’s positioning.
   

Signs of Front Idler Pillow Block Wear
Recognizing the signs of front idler pillow block wear early can help prevent more significant damage to the undercarriage. Here are some common symptoms:

• Uneven Track Wear: If the pillow block is worn, it can cause the tracks to wear unevenly. This can manifest as abnormal wear patterns, with some sections of the track showing more damage than others.
  
• Loose or Slack Tracks: As the pillow block wears, the track tension may become inconsistent, causing the tracks to become loose or slack. This can lead to a loss of power, poor performance, and increased risk of track slippage.
  
• Noise and Vibration: Worn idler components often cause excessive noise and vibration during operation. If the pillow block is damaged, it can cause the idler wheel to move erratically, producing unusual sounds or vibrations that can be felt throughout the machine.
  
• Visible Damage: Inspecting the front idler and pillow block regularly can reveal visible signs of wear, such as cracks, deformation, or excessive play in the component.
  

Troubleshooting and Solutions
Addressing front idler pillow block wear on the Hitachi EX 120-2 requires a combination of preventive maintenance, proper adjustments, and occasional component replacement. Below are some steps and solutions to extend the life of the pillow block:
1. Regular Inspection and Maintenance
Regularly inspecting the front idler assembly is essential for early detection of wear. Here’s what to look for during inspections:

• Inspect the pillow block for cracks, wear, or loose bolts.
  
• Check the alignment of the idler and ensure that it’s centered and not tilted.
  
• Ensure that the track tension is within the manufacturer’s recommended range.
  
• Inspect the lubrication system to ensure that the pillow block is receiving adequate lubrication.
  

2. Adjust Track Tension
Improper track tension is one of the leading causes of wear on the front idler pillow block. If the tracks are too tight, the additional friction can accelerate wear on the pillow block, while too loose tracks can cause excessive movement. Ensure that the tracks are adjusted according to the manufacturer's specifications and that the correct amount of slack is maintained.
3. Clean and Lubricate the Idler System
Contaminants can cause significant wear on the pillow block, so it's important to regularly clean the track system to prevent debris from entering the components. Use compressed air or a high-pressure washer to remove dirt and debris from the undercarriage. After cleaning, ensure that the pillow block is properly lubricated to reduce friction and wear. Follow the manufacturer's guidelines for the appropriate type of lubricant and the correct frequency of lubrication.
4. Replace Worn Components
If the front idler pillow block is showing signs of severe wear, such as cracking or significant damage, it may be necessary to replace it. Be sure to use OEM (Original Equipment Manufacturer) parts for the replacement to ensure compatibility and maintain the machine's performance. Additionally, inspect other components in the track system, such as the idler wheel, bearings, and bushings, as they may also require attention or replacement.
5. Preventative Measures for High-Load Operations
If your EX 120-2 is frequently used in high-load operations, consider implementing measures to reduce stress on the undercarriage. For example, avoid overloading the machine and use proper lifting techniques to reduce strain on the tracks. Additionally, consider using track pads or other protective accessories when working on rough or abrasive surfaces.
Conclusion
The front idler pillow block on the Hitachi EX 120-2 plays a critical role in maintaining the stability and performance of the machine's track system. While wear on this component is inevitable over time, regular maintenance, proper track tension, and timely repairs can significantly extend the life of the pillow block and other track components. By understanding the causes of wear and taking proactive steps to address them, operators can keep their EX 120-2 running efficiently and reduce the need for costly repairs or replacements.