Replacing Chains and Sprockets on a Kobelco 135 Without Breaking the Bank

[MikePhua]

The Kobelco 135 SR LC Excavator and Its Market Legacy
The Kobelco 135 SR LC is a compact radius excavator designed for tight urban job sites and utility work. Introduced in the early 2000s, it quickly gained traction in North America and Asia due to its balance of power, maneuverability, and fuel efficiency. With an operating weight around 13.5 metric tons and a Yanmar or Isuzu diesel engine depending on the production year, the 135 SR LC became a favorite among contractors who needed performance without the bulk of full-sized machines.
Kobelco Construction Machinery, originally part of Kobe Steel, has a long-standing reputation for hydraulic innovation. By 2010, Kobelco had sold over 100,000 excavators globally, with the 135 series accounting for a significant share in the mid-size segment. Its undercarriage components—chains, sprockets, rollers, and grousers—are engineered for durability but inevitably wear out, especially in high-impact or abrasive environments.
When to Replace Chains and Sprockets
Undercarriage wear is often gradual, but certain signs indicate it’s time for replacement:

• Chain bushings worn through or cracked
  
• Sprocket teeth becoming sharp or “hooked”
  
• Excessive track tension even after link removal
  
• Uneven wear on rollers or idlers
  
• Increased fuel consumption due to drag
  

In the case of the Kobelco 135, one operator had previously removed a link to reduce tension, but the bushings continued to degrade. This is a common stopgap measure, but once bushings wear through, the chain loses its structural integrity and can damage sprockets and final drives.
Understanding Undercarriage Terminology

• Track Chains: Also called rails, these are the linked assemblies that wrap around the undercarriage and engage with the sprockets.
  
• Sprockets: Toothed wheels that drive the chains via the final drive motors.
  
• Bushings: Cylindrical sleeves between chain links that absorb rotational stress.
  
• Grousers: The raised pads on track shoes that provide traction.
  

While grousers may still be in good condition, worn chains and sprockets can cause misalignment and reduce overall efficiency.
Aftermarket vs OEM Parts
Original Equipment Manufacturer (OEM) parts offer guaranteed fit and performance but often come at a premium. For machines like the Kobelco 135, aftermarket suppliers have filled the gap with high-quality alternatives.
Popular aftermarket brands include:

• ITR (Italian Tractor Replacement): Known for consistent metallurgy and wear resistance.
  
• S&S Tractor: A regional supplier with competitive pricing and solid customer support.
  
• Berco: A legacy brand with decades of experience in undercarriage systems.
  

While some suppliers like Value Part have exited the market, others have expanded their offerings to include full undercarriage kits, often priced 30–40% below OEM.
Cost Breakdown and Budgeting Tips
Replacing chains and sprockets on a mid-size excavator typically costs:

• Track chains: $1,800–$2,500 per set
  
• Sprockets: $400–$700 each
  
• Labor: $600–$1,200 depending on shop rates
  

To reduce costs:

• Reuse grousers if they’re within spec
  
• Source parts during off-season when demand is lower
  
• Consider bundling with other maintenance tasks (e.g., roller replacement)
  

In one case, a contractor in Ohio saved over $1,000 by purchasing an ITR kit during winter and installing it in-house with a mobile press.
Installation Considerations and Common Pitfalls
Installing new chains and sprockets requires precision:

• Always match pitch and link count to OEM specs
  
• Use a hydraulic press to pin chains—hammering can distort bushings
  
• Align sprockets carefully to avoid premature wear
  
• Check final drive seals for leaks before reassembly
  

A misaligned sprocket can cause “ratcheting,” where the chain skips teeth under load. This not only damages the sprocket but can shear drive lugs and compromise the final drive motor.
Field Anecdote from a Quarry Operation
In 2019, a quarry operator in Pennsylvania replaced the undercarriage on a Kobelco 135 using aftermarket chains and sprockets. Initially, the machine tracked well, but after 200 hours, the right track began slipping. Inspection revealed that the sprocket had been installed off-center by 3 mm, causing uneven tooth engagement. After realignment and re-torquing, the issue resolved, and the machine returned to full service.
Preventive Maintenance and Longevity Strategies
To extend the life of new chains and sprockets:

• Maintain proper track tension—too tight accelerates wear
  
• Clean tracks daily in muddy or abrasive conditions
  
• Rotate tracks periodically to balance wear
  
• Inspect rollers and idlers every 250 hours
  

Using a track wear gauge and logging measurements can help predict replacement intervals. On average, chains and sprockets last 2,000–3,000 hours depending on terrain and operator habits.
Conclusion
Replacing chains and sprockets on a Kobelco 135 doesn’t have to drain your budget. With smart sourcing, careful installation, and preventive care, operators can restore undercarriage performance and avoid costly downtime. Whether choosing OEM or aftermarket, the key is matching quality with application—and remembering that in the world of excavation, traction is everything.