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The Austin-Western Super 300 Legacy
The Austin-Western Super 300 motor grader was a product of one of America’s oldest road machinery manufacturers. Austin-Western, founded in 1877, was known for its innovative grader designs and robust mechanical engineering. The Super 300, introduced in the 1960s, was a high-powered, rigid-frame grader built for highway construction, municipal road maintenance, and mining operations. It featured a mechanical driveline, torque converter transmission, and a mid-mounted moldboard, making it ideal for precision grading and heavy-duty earthmoving.
By the time Clark Equipment acquired Austin-Western in the 1970s, the Super 300 had already earned a reputation for durability and straightforward field serviceability. Thousands were sold across North America, and many remain in use today, particularly in rural counties and private contractor fleets.
Understanding the Driveline Brake System
Unlike conventional wheel-mounted service brakes, the Super 300 uses a driveline brake mounted directly on the transmission output shaft. This design allows the brake to act on the entire drivetrain, including the differential and rear axles, providing consistent stopping power regardless of wheel slip or terrain.
Key components include:
Common Issues and Field Diagnosis
Over time, the driveline brake can suffer from wear, contamination, or misadjustment. Symptoms include:
Servicing and Adjustment Procedures
To maintain optimal brake function:
Preventive Measures and Upgrades
To extend the life of the driveline brake:
Operator Anecdotes and Practical Wisdom
A county road crew in Iowa used their Super 300 for winter grading and snow removal. They found that the driveline brake was prone to freezing due to moisture ingress. After installing a heat shield and applying anti-seize to the linkage, the issue was resolved. They now inspect the brake weekly during cold months.
In another case, a contractor in Arizona rebuilt his Super 300’s brake system using salvaged parts from a retired Clark grader. He fabricated a new band from semi-metallic lining and adjusted the linkage to match the original geometry. The grader passed inspection and returned to service on a desert road project.
Historical Footnotes and Production Impact
The Super 300 was one of Austin-Western’s final models before the brand was absorbed into Clark’s grader division. Its mechanical simplicity and robust frame made it popular in regions with limited access to dealer support. While production numbers are hard to verify, estimates suggest over 5,000 units were built between 1965 and 1975.
Today, restoration enthusiasts and small contractors continue to maintain these machines, often fabricating parts or sourcing components from salvage yards. The driveline brake, though unconventional by modern standards, remains a symbol of mid-century engineering focused on reliability and field serviceability.
Conclusion
The driveline brake on the Austin-Western Super 300 is a unique and effective system for securing and stopping the grader under varied conditions. With proper maintenance, adjustment, and occasional upgrades, it can deliver consistent performance even decades after manufacture. As with many legacy machines, understanding the mechanical logic behind the design allows operators to keep these graders working reliably—grading roads, shaping ditches, and holding their ground with every pull of the lever.
The Austin-Western Super 300 motor grader was a product of one of America’s oldest road machinery manufacturers. Austin-Western, founded in 1877, was known for its innovative grader designs and robust mechanical engineering. The Super 300, introduced in the 1960s, was a high-powered, rigid-frame grader built for highway construction, municipal road maintenance, and mining operations. It featured a mechanical driveline, torque converter transmission, and a mid-mounted moldboard, making it ideal for precision grading and heavy-duty earthmoving.
By the time Clark Equipment acquired Austin-Western in the 1970s, the Super 300 had already earned a reputation for durability and straightforward field serviceability. Thousands were sold across North America, and many remain in use today, particularly in rural counties and private contractor fleets.
Understanding the Driveline Brake System
Unlike conventional wheel-mounted service brakes, the Super 300 uses a driveline brake mounted directly on the transmission output shaft. This design allows the brake to act on the entire drivetrain, including the differential and rear axles, providing consistent stopping power regardless of wheel slip or terrain.
Key components include:
- Brake drum mounted on the driveline yoke
- External contracting brake band or internal shoe assembly
- Mechanical linkage or hydraulic actuator
- Return springs and adjustment cams
Common Issues and Field Diagnosis
Over time, the driveline brake can suffer from wear, contamination, or misadjustment. Symptoms include:
- Weak braking force or delayed engagement
- Squealing or grinding noises during application
- Brake drag when released
- Excessive pedal travel or spongy feel
- Worn brake lining or band material
- Oil contamination from leaking transmission seals
- Broken return springs or seized linkage
- Misaligned drum or warped brake shoes
Servicing and Adjustment Procedures
To maintain optimal brake function:
- Inspect the brake drum for scoring or glazing
- Clean all components with brake cleaner and wire brush
- Replace worn linings with OEM or high-friction aftermarket material
- Adjust the brake band or shoes using the cam or threaded rod until slight drag is felt, then back off slightly
- Lubricate pivot points and linkage joints with high-temperature grease
- Test brake engagement at idle and under load
Preventive Measures and Upgrades
To extend the life of the driveline brake:
- Replace output shaft seals every 2,000 hours or when leakage is observed
- Avoid using the brake for prolonged deceleration—it’s not designed for continuous duty
- Install a dust shield or splash guard to protect the drum from debris
- Use a brake temperature indicator if operating in steep terrain
Operator Anecdotes and Practical Wisdom
A county road crew in Iowa used their Super 300 for winter grading and snow removal. They found that the driveline brake was prone to freezing due to moisture ingress. After installing a heat shield and applying anti-seize to the linkage, the issue was resolved. They now inspect the brake weekly during cold months.
In another case, a contractor in Arizona rebuilt his Super 300’s brake system using salvaged parts from a retired Clark grader. He fabricated a new band from semi-metallic lining and adjusted the linkage to match the original geometry. The grader passed inspection and returned to service on a desert road project.
Historical Footnotes and Production Impact
The Super 300 was one of Austin-Western’s final models before the brand was absorbed into Clark’s grader division. Its mechanical simplicity and robust frame made it popular in regions with limited access to dealer support. While production numbers are hard to verify, estimates suggest over 5,000 units were built between 1965 and 1975.
Today, restoration enthusiasts and small contractors continue to maintain these machines, often fabricating parts or sourcing components from salvage yards. The driveline brake, though unconventional by modern standards, remains a symbol of mid-century engineering focused on reliability and field serviceability.
Conclusion
The driveline brake on the Austin-Western Super 300 is a unique and effective system for securing and stopping the grader under varied conditions. With proper maintenance, adjustment, and occasional upgrades, it can deliver consistent performance even decades after manufacture. As with many legacy machines, understanding the mechanical logic behind the design allows operators to keep these graders working reliably—grading roads, shaping ditches, and holding their ground with every pull of the lever.
