Restoring the Hough HA/H25 Loader: Legacy Iron, Mechanical Ingenuity, and Field Lessons

The Hough HA and H25 loaders represent a bygone era of American heavy equipment manufacturing—machines built with simplicity, brute strength, and mechanical honesty. Produced in the 1950s and 1960s by Hough (later acquired by International Harvester), these wheel loaders were designed for rugged industrial use, from gravel pits to logging yards. Today, restoring one is a labor of love, requiring patience, fabrication skills, and a deep respect for old-school engineering.

Terminology Notes

• Torque Converter: A fluid coupling between the engine and transmission that multiplies torque and allows smooth gear changes.
• Planetary Gear Set: A compact gear system used in transmissions to provide multiple gear ratios.
• Articulated Steering: A steering system where the machine bends at a central pivot, common in modern loaders but absent in early rigid-frame models.
• Dry Disc Brakes: A braking system using friction between metal discs and pads, without hydraulic fluid immersion.
• Hydraulic Spool Valve: A control valve that directs hydraulic fluid to cylinders based on lever input.

Machine Profile: Hough HA/H25 Loader

• Engine: Often equipped with International Harvester inline 6-cylinder gasoline or diesel engines
• Transmission: 3-speed or 4-speed manual with torque converter
• Operating Weight: ~12,000–15,000 lbs depending on configuration
• Bucket Capacity: ~1.5–2 cubic yards
• Steering: Rigid frame with front axle pivot
• Brakes: Mechanical dry disc or drum brakes
• Hydraulics: Open-center system with gear pump

These loaders were built with minimal electronics, relying on mechanical linkages, cable-actuated controls, and robust castings.

Common Restoration Challenges

Engine and Transmission Wear

• Cylinder scoring, valve seat erosion, and worn bearings are common in original engines
• Carburetors may be gummed up or cracked
• Torque converters may leak or fail to engage properly
• Transmission gears may be chipped or misaligned

Hydraulic System Issues

• Leaking hoses and brittle seals
• Spool valves sticking due to rust or contamination
• Gear pumps losing prime or pressure
• Cylinders pitted or bypassing internally

Brake and Steering Problems

• Brake linkages seized or worn beyond adjustment
• Drums or discs rusted and out of round
• Steering knuckles loose or cracked
• Tie rods bent or missing

Electrical and Fuel System Faults

• Wiring harnesses often brittle or missing entirely
• Starter solenoids and generators may be obsolete
• Fuel tanks rusted internally, causing clogging
• Mechanical gauges often non-functional

Field Case: Gravel Yard Loader in Alberta

A retired operator in Alberta began restoring a Hough HA that had sat idle for 20 years. The engine turned over but had no spark. After rebuilding the distributor and replacing the coil, he got it running. The torque converter was leaking, so he fabricated a new seal using a lathe and Viton stock. “It’s not pretty,” he said, “but it moves dirt like it did in ’68.”

Restoration Strategy

• Begin with engine compression and ignition system
• Drain and inspect all fluids for contamination
• Rebuild carburetor or fuel injection system
• Replace hydraulic hoses and clean spool valves
• Inspect brakes and steering for mechanical integrity
• Fabricate missing parts using donor machines or machine shop tools
• Rewire with modern harnesses and fuse blocks
• Replace gauges with aftermarket mechanical units if originals are unavailable

Parts Sourcing and Fabrication

• Many parts are no longer available from OEM sources
• Salvage yards and vintage tractor clubs may have donor machines
• Machine shops can fabricate bushings, pins, and seals
• Hydraulic shops can rebuild cylinders and pumps
• Online forums and vintage equipment groups offer diagrams and advice

Operator Anecdotes and Practical Wisdom

A contractor in Georgia restored a Hough H25 for use on his farm. He replaced the bucket pins with custom-machined 4140 steel and added LED work lights. “It’s slow,” he said, “but it’ll outlift anything in its class.”

Another story comes from a logging crew in Maine. Their Hough loader had a cracked bellhousing. They welded it with nickel rod and reinforced it with a steel plate. “It’s ugly,” the welder said, “but it’s stronger than stock.”

Preventive Maintenance Tips

• Change engine oil every 100 hours or annually
• Grease all pivot points monthly
• Inspect hydraulic fluid for water or metal
• Keep fuel tank full to prevent condensation
• Exercise brakes and steering weekly to prevent seizing
• Store under cover to reduce rust and UV damage

Conclusion: Restoring a Legend

The Hough HA and H25 loaders are more than machines—they’re mechanical time capsules. Restoring one is a tribute to the era of cast iron, cable linkages, and hand-built reliability. With patience, ingenuity, and a few busted knuckles, these loaders can return to work, proving that legacy iron still has a place in the dirt. In the world of vintage equipment, the Hough name still carries weight—literally and figuratively.