Rebuilding the Undercarriage of the Caterpillar 953 Track Loader

[MikePhua]

The 953 and Its Role in Earthmoving History
The Caterpillar 953 track loader was introduced in the early 1980s as part of Cat’s push to modernize its crawler loader lineup. Designed to replace the aging 951 and 955 series, the 953 offered hydrostatic drive, improved operator ergonomics, and a more balanced undercarriage layout. With an operating weight of around 30,000 lbs and a bucket capacity of 2.5 cubic yards, the 953 became a staple in grading, demolition, and site prep operations.
Caterpillar, founded in 1925, has sold hundreds of thousands of track loaders globally. The 953 series alone has seen multiple iterations—B, C, D, and K—each refining emissions, hydraulics, and cab comfort. But across all generations, the undercarriage remains the heart of the machine’s longevity and operating cost.
When Should You Rebuild the Undercarriage
Operators often face a dilemma when their 953 begins walking off the tracks during turns or shows signs of uneven wear. Pins may have been turned, sprocket segments replaced, and yet the machine still struggles to track properly. This signals that the undercarriage is no longer functioning as a system.
Key indicators for rebuild:

• Track derailment during turns
  
• Uneven wear on sprockets and rollers
  
• Idlers reaching end of adjustment range
  
• Hydraulic adjuster cylinders leaking
  
• Rails worn beyond 70% of life
  

Partial repairs—such as replacing only the rails—may offer short-term relief but often accelerate wear on remaining components. Mixing old and new parts disrupts load distribution and leads to premature failure.
Terminology Clarification

• Rails (Chains): The steel links that form the track, guiding rollers and sprockets.
  
• Idlers: Front wheels that guide the track and maintain tension.
  
• Bottom Rollers: Support the weight of the machine and guide the track along the frame.
  
• Sprocket Segments: Replaceable teeth that drive the track via the final drive.
  

OEM vs Aftermarket Components
Some operators report poor results with aftermarket undercarriage kits. Tracks may not stay aligned, components wear unevenly, and resale value drops. While quality jobber parts exist, low-cost imports—especially from unverified sources—can lead to costly downtime.
Recommendations:

• Use OEM Caterpillar components for high-hour machines or resale-sensitive fleets
  
• Consider reputable aftermarket brands only with verified performance history
  
• Avoid mixing aftermarket rails with OEM rollers or idlers unless compatibility is confirmed
  
• Request full undercarriage measurement reports from Cat PSSR (Parts & Service Sales Rep)
  

In one case, a contractor installed a full aftermarket kit on two 953s. Within weeks, both machines began throwing tracks under load. After inspection, it was found that the rail pitch was slightly off, causing misalignment with the sprockets. The kits were removed and replaced with OEM parts at a financial loss.
The Undercarriage as a System
Undercarriage components wear together, but not always at the same rate. Replacing one part without addressing others can create stress points. For example, new rails paired with worn rollers will cause the rollers to wear faster and may damage the rail links.
Best practice:

• Replace rails, rollers, idlers, and sprockets as a complete set
  
• Inspect track frames for bending or looseness
  
• Check alignment between sprockets and track path
  
• Verify adjuster cylinder seals and piston travel
  

A Cat dealer can provide a wear report showing percentage life remaining on each component. This helps prioritize replacements and avoid discarding parts with usable life.
Operating Costs and Longevity Strategy
A full undercarriage rebuild on a 953 can cost $15,000–$25,000 depending on parts and labor. However, when done correctly, it can extend machine life by 4,000–6,000 hours. Skipping components or using low-grade parts may reduce that to under 2,000 hours.
Cost-saving tips:

• Schedule rebuilds during seasonal downtime
  
• Use remanufactured components where available
  
• Track component hours and inspect quarterly
  
• Avoid aggressive turning on hard surfaces to reduce side wear
  

In Missouri, a grading contractor rebuilt two 953s with full OEM kits and saw a 40% reduction in operating costs over three years due to fewer breakdowns and improved fuel efficiency.
Conclusion
Rebuilding the undercarriage of a Caterpillar 953 is not just a parts swap—it’s a strategic investment in machine performance and reliability. Treating the undercarriage as a system, using quality components, and timing the rebuild properly can dramatically improve longevity and reduce operating costs. Whether you're running a fleet or a single machine, the right rebuild approach keeps your loader tracking straight and earning its keep.