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The International TD8E and Its Mechanical Heritage
The International TD8E crawler dozer, produced by International Harvester in the late 1970s, was a mid-sized workhorse designed for grading, land clearing, and light earthmoving. With an operating weight of approximately 17,000 pounds and powered by a D239 diesel engine, the TD8E featured a powershift transmission and a planetary final drive system. One of its defining features was its internal wet disc brake system, which provided reliable stopping power and steering control through clutch-brake actuation.
Understanding the Brake System Configuration
The TD8E uses a dual-function braking system where the foot brake and steering levers operate internal wet disc brakes. These brakes are immersed in Hy-Tran hydraulic oil, which serves both as a lubricant and hydraulic medium. The system relies on mechanical linkages and hydraulic pressure to engage the brake packs located within the final drive housings.
When the operator pulls a steering lever, it disengages the clutch on one side and simultaneously applies the brake, allowing the machine to pivot. The foot brake applies both sides simultaneously for stopping. This system is robust but requires precise adjustment and clean hydraulic fluid to function correctly.
Common Issues After a Brake Rebuild
After relining the brake shoes and reassembling the system, operators may encounter a complete lack of braking response. This can be caused by several factors:
Troubleshooting and Adjustment Tips
To resolve post-rebuild issues:
Many operators have found success by referencing both the factory service manual and instructional videos. These resources often highlight subtle steps that are easy to overlook, such as the orientation of return springs or the sequence of adjustments. One operator noted that a missed step during reassembly—corrected after watching a detailed video—was the root cause of non-functional brakes.
Conclusion
Rebuilding the brake system on a 1978 International TD8E requires more than just replacing linings. It demands careful attention to mechanical adjustments, fluid integrity, and component alignment. When done correctly, the result is a responsive and reliable braking system that restores full control to this classic dozer. For those working with vintage equipment, patience and precision are just as important as parts and tools.
The International TD8E crawler dozer, produced by International Harvester in the late 1970s, was a mid-sized workhorse designed for grading, land clearing, and light earthmoving. With an operating weight of approximately 17,000 pounds and powered by a D239 diesel engine, the TD8E featured a powershift transmission and a planetary final drive system. One of its defining features was its internal wet disc brake system, which provided reliable stopping power and steering control through clutch-brake actuation.
Understanding the Brake System Configuration
The TD8E uses a dual-function braking system where the foot brake and steering levers operate internal wet disc brakes. These brakes are immersed in Hy-Tran hydraulic oil, which serves both as a lubricant and hydraulic medium. The system relies on mechanical linkages and hydraulic pressure to engage the brake packs located within the final drive housings.
When the operator pulls a steering lever, it disengages the clutch on one side and simultaneously applies the brake, allowing the machine to pivot. The foot brake applies both sides simultaneously for stopping. This system is robust but requires precise adjustment and clean hydraulic fluid to function correctly.
Common Issues After a Brake Rebuild
After relining the brake shoes and reassembling the system, operators may encounter a complete lack of braking response. This can be caused by several factors:
- Air entrapment in the hydraulic circuit, preventing proper pressure buildup
- Incorrect brake shoe adjustment, leading to insufficient contact or engagement
- Improper installation of return springs or linkage misalignment
- Contaminated or incorrect hydraulic fluid, affecting brake pack performance
Troubleshooting and Adjustment Tips
To resolve post-rebuild issues:
- Double-check all mechanical adjustments as per the service manual. The brake linkage must be tensioned correctly to ensure full engagement.
- Bleed the hydraulic system thoroughly. Although the TD8E’s system is self-priming, trapped air can still cause soft or non-functional brakes. Let the machine idle and cycle the controls to purge air.
- Inspect the master cylinder and brake valve for wear or internal leakage. A faulty seal can prevent pressure buildup.
- Verify the correct installation of brake shoes and springs. Even a small misalignment can prevent proper actuation.
- Ensure the Hy-Tran fluid is clean and at the correct level. Dirty or low fluid can impair brake function and damage internal components.
Many operators have found success by referencing both the factory service manual and instructional videos. These resources often highlight subtle steps that are easy to overlook, such as the orientation of return springs or the sequence of adjustments. One operator noted that a missed step during reassembly—corrected after watching a detailed video—was the root cause of non-functional brakes.
Conclusion
Rebuilding the brake system on a 1978 International TD8E requires more than just replacing linings. It demands careful attention to mechanical adjustments, fluid integrity, and component alignment. When done correctly, the result is a responsive and reliable braking system that restores full control to this classic dozer. For those working with vintage equipment, patience and precision are just as important as parts and tools.
