08-27-2025, 09:05 PM
Issue Background
On the Cat 955L track loader (prefix 13X), the roller frame may loosen over time, causing the final drive seal to leak and misalignment of the sprocket. Tightening or adjusting the sprocket helps eliminate leaks and restores proper engagement between track and drive components.
Equipment History and Context
The Cat 955L is a compact to mid-size track loader popular in construction and earthmoving, produced from the late 1970s through the early 1980s. Powered by the reliable 3304 engine, it shares many systems with the 955K series but features refined operator ergonomics and stronger final drives—boosting durability and appeal in rugged job-site environments.
Terminology Explained
An experienced operator in Tennessee noticed his 955L running low on track-side oil and felt excessive play in the roller frame. Upon inspection, he discovered the inner shims had crept loose, pinching the idler and shifting the sprocket seal. Removing one shim, freeing the idler, and re-securing the adjuster restored tension and halted leakage. Track engagement and machine performance returned to factory feel—preventing costly final drive repair.
Industry Insight
Heavy equipment maintainers recognize sprocket misalignment and difficult adjuster access as common issues in aging 955L units. In response, many workshops now include shim inspection and idler clearance checks in preventive maintenance routines. This proactive approach improves seal life and track reliability, reducing unplanned downtime and service costs.
Summary
For Cat 955L track loaders with prefix 13X, addressing final drive leaks often starts with roller frame tightening and sprocket adjustment. Freeing the idler—by easing spring pressure and removing shims—provides necessary access to the adjuster mechanism. Restoring proper tension and alignment eliminates leaks and ensures smoother track operations. Regular inspection and maintenance of shims, bolts, and idler pathways are key to long-term reliability.
On the Cat 955L track loader (prefix 13X), the roller frame may loosen over time, causing the final drive seal to leak and misalignment of the sprocket. Tightening or adjusting the sprocket helps eliminate leaks and restores proper engagement between track and drive components.
Equipment History and Context
The Cat 955L is a compact to mid-size track loader popular in construction and earthmoving, produced from the late 1970s through the early 1980s. Powered by the reliable 3304 engine, it shares many systems with the 955K series but features refined operator ergonomics and stronger final drives—boosting durability and appeal in rugged job-site environments.
Terminology Explained
- Prefix 13X: Denotes a serial pattern identifying 955L models, commonly built in late 1970s.
- Roller frame: The subframe on which rollers ride, supporting the track—and vital in maintaining tension.
- Final drive seal: A seal between the sprocket assembly and drive housing that prevents lubricant loss.
- Idler: A wheel at the front of the track system that helps guide and tension the track.
- Shims: Thin metal spacers used to position and align components precisely.
- Track adjuster: A hydraulic or spring-loaded device controlling track tension and roller frame alignment.
- Tighten the roller frame bolts to mitigate movement—this often reduces sprocket seal leaks.
- To access the adjuster mechanism effectively, relieve idler binding:
- Loosen the frame’s spring-pressure retaining bolts.
- Remove one or two inner shims to free the idler’s travel—this allows it to move forward and create access clearance.
- Loosen the frame’s spring-pressure retaining bolts.
- Once the idler shifts forward, the adjuster cylinder and tensioning mechanism become accessible for service.
- Secure machine safely, relieving pressure from tensioning spring components.
- Loosen bolts securing the roller frame springs to relieve preload.
- Remove one or two inner shims near the idler to permit forward movement.
- Gently pry or pull the idler forward to create enough space.
- Access and service the sprocket adjuster—tighten or rebuild as needed.
- Reassemble: reinstall shims, tighten bolts, re-engage spring preload, and torque to specification.
- Verify proper track tension and inspect final drive seal for leaks after operation.
- Regularly inspect roller frame bolts—tighten at 500-hour intervals to maintain alignment.
- Monitor final drive housing for any early signs of lubricant seepage.
- Check and replace shims if worn or fatigued—use correct material thickness for precise tracking.
- Promote smooth idler movement by cleaning wear strips and replacing if distorted or welded poorly.
An experienced operator in Tennessee noticed his 955L running low on track-side oil and felt excessive play in the roller frame. Upon inspection, he discovered the inner shims had crept loose, pinching the idler and shifting the sprocket seal. Removing one shim, freeing the idler, and re-securing the adjuster restored tension and halted leakage. Track engagement and machine performance returned to factory feel—preventing costly final drive repair.
Industry Insight
Heavy equipment maintainers recognize sprocket misalignment and difficult adjuster access as common issues in aging 955L units. In response, many workshops now include shim inspection and idler clearance checks in preventive maintenance routines. This proactive approach improves seal life and track reliability, reducing unplanned downtime and service costs.
Summary
For Cat 955L track loaders with prefix 13X, addressing final drive leaks often starts with roller frame tightening and sprocket adjustment. Freeing the idler—by easing spring pressure and removing shims—provides necessary access to the adjuster mechanism. Restoring proper tension and alignment eliminates leaks and ensures smoother track operations. Regular inspection and maintenance of shims, bolts, and idler pathways are key to long-term reliability.
