Identifying and Replacing Track Rollers on the Hitachi 200B Excavator

[MikePhua]

The Hitachi 200B and Its Undercarriage Design
The Hitachi 200B excavator is part of the EX200 series, a globally recognized line of mid-size hydraulic excavators introduced in the late 1980s and refined through the 1990s. Known for their reliability and ease of maintenance, these machines were widely used in construction, mining, and forestry. The 200B variant features a conventional undercarriage layout with a series of bottom rollers (also called track rollers) that support the weight of the machine and guide the track chain during movement.
Track rollers are critical to maintaining proper track tension, reducing vibration, and ensuring smooth travel over uneven terrain. Each side of the undercarriage typically includes 7 to 9 bottom rollers, depending on the model and configuration.
Understanding Track Roller Types and Functions
Track rollers come in two primary forms:

• Single flange rollers: Used on the inside of the track frame, guiding the track chain from the center.
  
• Double flange rollers: Positioned to guide the track chain from both sides, offering better lateral stability.
  

The Hitachi 200B commonly uses double flange bottom rollers, forged from high-strength steel such as 50Mn or 40MnB, and heat-treated to a surface hardness of HRC 52–58. These rollers are sealed and lubricated for life, with internal bushings and shafts designed to withstand high impact loads.
Identifying the Correct Replacement Roller
To identify the correct roller for a Hitachi 200B, consider the following parameters:

• Roller diameter: Typically ranges from 220 mm to 260 mm depending on the model variant.
  
• Bolt hole spacing: Must match the mounting pattern on the track frame.
  
• Shaft diameter and bushing type: Critical for proper fit and load distribution.
  
• Part number: Often stamped on the roller body or available in the parts manual.
  

If the original part number is missing, cross-referencing with compatible models such as EX200-2, EX200-3, or EX200LC-3 can help. Many aftermarket suppliers list rollers by machine model and dimensions.
Common Issues and Wear Patterns
Track rollers wear over time due to:

• Abrasive soil conditions
  
• Improper track tension
  
• Lack of lubrication in older models
  
• Misalignment from bent track frames or worn bushings
  

Symptoms of worn rollers include:

• Clunking noises during travel
  
• Uneven track wear
  
• Increased vibration
  
• Visible flat spots or cracks on the roller surface
  

In one case, a contractor noticed excessive vibration and discovered that two rollers had seized due to internal bushing failure. Replacing them restored smooth travel and reduced undercarriage stress.
Replacement and Installation Tips
When replacing rollers:

• Always replace in pairs to maintain balance
  
• Use torque specs from the service manual for mounting bolts
  
• Clean the mounting surface thoroughly before installation
  
• Apply anti-seize compound to bolts to prevent corrosion
  
• Check track tension after installation to avoid overloading new rollers
  

Sourcing and Aftermarket Options
OEM rollers for the Hitachi 200B may be expensive or discontinued. Fortunately, aftermarket suppliers offer high-quality replacements with similar metallurgy and performance. Brands specializing in undercarriage parts often provide:

• Forged steel rollers with induction-hardened surfaces
  
• Sealed and lubricated assemblies
  
• Warranty coverage ranging from 12 to 18 months
  

Some suppliers also offer remanufactured rollers, which can be a cost-effective solution for older machines.
Conclusion
Identifying and replacing track rollers on the Hitachi 200B requires attention to detail and understanding of undercarriage mechanics. By measuring key dimensions, cross-referencing compatible models, and selecting high-quality replacements, operators can extend the life of their excavator and maintain optimal performance. Regular inspection and timely replacement of worn rollers are essential to preserving the integrity of the track system and avoiding costly downtime.