9 hours ago
Legacy of the Clark Michigan Scraper Series
The Clark Michigan 110-11 paddle scraper, often referred to as an elevating scraper, was part of a robust line of earthmoving machines produced during the mid-20th century. Clark Equipment Company, founded in 1903, became a major force in construction and mining equipment, with its Michigan division specializing in wheel loaders and scrapers. The 110-11 model was designed for medium-duty grading and hauling, featuring a paddle elevator system that lifted material into the bowl without relying solely on gravity or push-loading.
These machines were widely used in road building, land leveling, and agricultural development. While exact production numbers are hard to trace, the 110 series was popular across North America, especially in rural and municipal fleets.
Engine and Transmission Configuration
Most 110-11 units were powered by Detroit Diesel 3-69 engines—a three-cylinder, two-stroke diesel known for its distinctive sound and high torque at low RPM. The transmission system was originally thought to be air-shifted, but further inspection revealed it to be hydraulically shifted. This hydraulic control system uses spool valves and pressure regulators to engage gears, making it more responsive than older pneumatic setups.
The transmission relies on a torque converter, specifically the C273 5-11 model, which multiplies engine torque and allows smooth gear transitions. However, excessive internal leakage in the converter—three times the acceptable bypass rate—can lead to poor hill-climbing performance and sluggish response.
Torque Converter and Hydraulic Shift Troubleshooting
Upon disassembly, the torque converter was found to have worn metal seals resembling piston rings. These seals are critical for maintaining pressure between rotating components. Replacing them restored partial functionality, but lingering clutch slippage suggested additional internal wear.
The hydraulic shift control, mounted atop the transmission, contained sticky valves that were cleaned and reassembled. After this service, the machine could shift through all gears and demonstrated strong traction in first gear, even spinning the wheels when the pan was engaged deeply.
Air System Misconceptions and Brake Considerations
Initial assumptions about an air-shifted transmission were corrected after reviewing the maintenance manual. However, the air system still plays a role in braking and auxiliary functions. A disabled or contaminated air system can affect parking brake engagement and safety interlocks. Operators should inspect air tanks, lines, and valves for moisture, corrosion, and debris.
Recommendations for Restoration and Operation
The restoration process was paused due to winter conditions, with the machine parked until indoor projects were completed. This highlights the importance of seasonal planning in equipment restoration. In warmer climates, such as southern Queensland, operators face the opposite challenge—heatwaves exceeding 100°F that demand shaded workspaces and hydration protocols.
Conclusion
Reviving a Clark Michigan 110-11 paddle scraper requires a blend of mechanical insight, historical documentation, and practical field testing. From misidentified shift systems to torque converter diagnostics, each step reveals the complexity and resilience of mid-century earthmoving technology. With careful attention to hydraulic and transmission components, these machines can return to productive service—preserving a legacy of American engineering in the dirt they were built to move.
The Clark Michigan 110-11 paddle scraper, often referred to as an elevating scraper, was part of a robust line of earthmoving machines produced during the mid-20th century. Clark Equipment Company, founded in 1903, became a major force in construction and mining equipment, with its Michigan division specializing in wheel loaders and scrapers. The 110-11 model was designed for medium-duty grading and hauling, featuring a paddle elevator system that lifted material into the bowl without relying solely on gravity or push-loading.
These machines were widely used in road building, land leveling, and agricultural development. While exact production numbers are hard to trace, the 110 series was popular across North America, especially in rural and municipal fleets.
Engine and Transmission Configuration
Most 110-11 units were powered by Detroit Diesel 3-69 engines—a three-cylinder, two-stroke diesel known for its distinctive sound and high torque at low RPM. The transmission system was originally thought to be air-shifted, but further inspection revealed it to be hydraulically shifted. This hydraulic control system uses spool valves and pressure regulators to engage gears, making it more responsive than older pneumatic setups.
The transmission relies on a torque converter, specifically the C273 5-11 model, which multiplies engine torque and allows smooth gear transitions. However, excessive internal leakage in the converter—three times the acceptable bypass rate—can lead to poor hill-climbing performance and sluggish response.
Torque Converter and Hydraulic Shift Troubleshooting
Upon disassembly, the torque converter was found to have worn metal seals resembling piston rings. These seals are critical for maintaining pressure between rotating components. Replacing them restored partial functionality, but lingering clutch slippage suggested additional internal wear.
The hydraulic shift control, mounted atop the transmission, contained sticky valves that were cleaned and reassembled. After this service, the machine could shift through all gears and demonstrated strong traction in first gear, even spinning the wheels when the pan was engaged deeply.
Air System Misconceptions and Brake Considerations
Initial assumptions about an air-shifted transmission were corrected after reviewing the maintenance manual. However, the air system still plays a role in braking and auxiliary functions. A disabled or contaminated air system can affect parking brake engagement and safety interlocks. Operators should inspect air tanks, lines, and valves for moisture, corrosion, and debris.
Recommendations for Restoration and Operation
- Inspect torque converter seals and measure bypass flow against manual specs
- Clean and lubricate hydraulic shift valves, especially after long storage
- Verify clutch pack integrity if slippage persists after converter repair
- Drain and flush air tanks, then test brake actuation under load
- Use OEM or matched aftermarket parts for torque converter rebuilds
The restoration process was paused due to winter conditions, with the machine parked until indoor projects were completed. This highlights the importance of seasonal planning in equipment restoration. In warmer climates, such as southern Queensland, operators face the opposite challenge—heatwaves exceeding 100°F that demand shaded workspaces and hydration protocols.
Conclusion
Reviving a Clark Michigan 110-11 paddle scraper requires a blend of mechanical insight, historical documentation, and practical field testing. From misidentified shift systems to torque converter diagnostics, each step reveals the complexity and resilience of mid-century earthmoving technology. With careful attention to hydraulic and transmission components, these machines can return to productive service—preserving a legacy of American engineering in the dirt they were built to move.
