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A collapsed idler wheel and failed track tension seal on the International Harvester TD-15C crawler dozer typically require full disassembly of the front track assembly, removal of the idler, and replacement of the tensioning components. While the repair is labor-intensive, it is a well-documented procedure among operators familiar with the TD-15 series.
IH TD-15C Background and Undercarriage Design
The TD-15C was part of International Harvester’s third-generation crawler dozer series, introduced in the late 1970s and produced into the 1980s before the construction division transitioned to Dresser Industries. Known for its balance of power and maneuverability, the TD-15C featured a 150 hp diesel engine, torque converter transmission, and a modular undercarriage system.
The track tensioning mechanism uses a grease-charged hydraulic cylinder located behind the front idler. When grease is pumped into the tension fitting, the cylinder extends, pushing the idler forward and tightening the track. A seal failure in this system causes the idler to retract, collapsing the track and halting movement.
Terminology Note
In Georgia, an operator removed the idler without detaching the blade, saving time but damaging the main pin during track disassembly. A replacement pin cost $50, and the seal was ordered alongside. The repair was completed in 90°F heat, and the machine returned to service with restored tension.
In New Zealand, a foreman recalled operating three TD-15s from new, logging over 20,000 hours. He emphasized the importance of maintaining wear strips and pivot shaft alignment, having witnessed a shaft break due to neglected guide wear.
Recommendations for Long-Term Reliability
Track tension failure on the IH TD-15C is a manageable but demanding repair. With proper tools, attention to alignment, and full component replacement, the machine can be restored to reliable operation. The TD-15C’s legacy of durability continues in the hands of operators who understand its mechanical systems and respect its design heritage.
IH TD-15C Background and Undercarriage Design
The TD-15C was part of International Harvester’s third-generation crawler dozer series, introduced in the late 1970s and produced into the 1980s before the construction division transitioned to Dresser Industries. Known for its balance of power and maneuverability, the TD-15C featured a 150 hp diesel engine, torque converter transmission, and a modular undercarriage system.
The track tensioning mechanism uses a grease-charged hydraulic cylinder located behind the front idler. When grease is pumped into the tension fitting, the cylinder extends, pushing the idler forward and tightening the track. A seal failure in this system causes the idler to retract, collapsing the track and halting movement.
Terminology Note
- Idler Wheel: The front-most wheel in the track assembly, responsible for maintaining tension.
- Track Adjuster: A hydraulic cylinder that pushes the idler forward to tighten the track.
- Grease Fitting: A zerk used to inject grease into the adjuster cylinder.
- Pivot Shaft Cap: A structural plate that secures the track frame to the pivot shaft.
- Master Link: A removable link in the track chain used to break and reassemble the track.
- Remove the blade assembly if necessary for access. In some cases, the blade can remain if clearance allows.
- Break the track by locating the master link just behind the idler. Remove two pads on each side and extract the master link pad.
- Support the idler using a cherry picker, overhead hoist, or large C-clamp to prevent uncontrolled movement.
- Release grease pressure by removing the cap near the tensioner zerk.
- Remove the stop blocks (typically four bolts) at the front of the track frame.
- Extract the idler using pry bars, hammers, and patience. The rear shaft and spring may drop slightly and require lifting during reassembly.
- Remove the plunger and wiper seal from the adjuster barrel. Clean all grease and inspect for rust or pitting.
- Replace all seals and components. If the barrel is pitted, a new adjuster may be required.
- Check the pivot shaft cap and shims. These center the track frame with the sprocket and prevent lateral movement.
- Inspect the sliding guide wear strips. Located mid-frame, these prevent excessive side play. Worn strips increase stress on the pivot shaft.
- Torque all bolts to spec. Loose fasteners can cause misalignment and premature wear.
In Georgia, an operator removed the idler without detaching the blade, saving time but damaging the main pin during track disassembly. A replacement pin cost $50, and the seal was ordered alongside. The repair was completed in 90°F heat, and the machine returned to service with restored tension.
In New Zealand, a foreman recalled operating three TD-15s from new, logging over 20,000 hours. He emphasized the importance of maintaining wear strips and pivot shaft alignment, having witnessed a shaft break due to neglected guide wear.
Recommendations for Long-Term Reliability
- Replace all tensioner components during service, not just the seal.
- Clean all grease from the barrel before reassembly.
- Monitor track alignment and wear strip condition monthly.
- Keep spare master link pins and seals on hand for field repairs.
Track tension failure on the IH TD-15C is a manageable but demanding repair. With proper tools, attention to alignment, and full component replacement, the machine can be restored to reliable operation. The TD-15C’s legacy of durability continues in the hands of operators who understand its mechanical systems and respect its design heritage.
