Removing the Crankshaft Pulley on a 1961 Allis-Chalmers D Grader

[MikePhua]

The Allis-Chalmers Legacy in Road Machinery
Allis-Chalmers, a name synonymous with American industrial innovation, began producing road graders in the mid-20th century after acquiring the Monarch Road Machinery Company. By 1961, the D series graders were well-established in municipal fleets and construction outfits across North America. These machines were powered by the rugged 262 cubic inch gasoline engine, known for its simplicity and torque delivery. Though production of Allis-Chalmers graders ceased decades ago, many units remain in service or restoration, prized for their mechanical accessibility and historical value.
Understanding the Crankshaft Pulley Assembly
The crankshaft pulley is a critical component mounted to the front of the engine’s crankshaft. It drives belts connected to the water pump, generator, and other accessories. On older engines like the Allis-Chalmers 262, the pulley is typically press-fit onto the crankshaft snout and may include a keyway for rotational alignment.
Terminology annotation:
- Crankshaft Pulley: A circular component attached to the crankshaft that transmits rotational force to accessory belts. - Keyway: A machined slot in the shaft and pulley that accepts a metal key to prevent slippage. - Press-Fit: A tight mechanical fit requiring force or tools to remove or install, often without fasteners.
Over time, corrosion, heat cycling, and belt tension can cause the pulley to seize onto the shaft, making removal difficult without proper tools and technique.
Safe Removal Techniques and Tooling
To remove the crankshaft pulley safely, technicians should first remove the radiator to gain unobstructed access. This step is essential on older graders with narrow engine compartments. Once exposed, the pulley may reveal tapped holes for a puller—though some models lack these features.
Recommended removal steps:

• Inspect for tapped holes and use a bolt-on puller if available
  
• If no threaded holes exist, use a bearing splitter behind the pulley
  
• Avoid jaw-type gear pullers, which can fracture the pulley edges
  
• Apply penetrating oil and allow time for seepage
  
• Use heat cautiously to expand the pulley hub without damaging seals
  

Terminology annotation:
- Bearing Splitter: A two-piece tool that grips behind a pulley or gear to allow safe pulling force. - Penetrating Oil: A low-viscosity lubricant designed to infiltrate rusted or seized joints. - Thermal Expansion: The increase in material size due to heat, used to loosen press-fit components.
One operator shared that his pulley had a stepped keyway, and after losing the original key, he had the pulley broached to accept a standard square key. This modification restored function without requiring a new pulley.
Identifying Hidden Fasteners and Set Screws
Some crankshaft pulleys on vintage engines include hidden fasteners or set screws. These may be recessed into the hub or obscured by grime. A flashlight and pick tool can help locate these features. In rare cases, pulleys may be retained by a bolt with no visible head, requiring extraction with a stud remover or reverse-thread tool.
If the pulley resists removal despite all visible fasteners being cleared, technicians should suspect:

• Double set screw arrangements
  
• Hidden retaining clips or snap rings
  
• Deformed keyways locking the pulley in place
  

Using a dial indicator to check for pulley wobble before removal can reveal whether the hub is bent or misaligned, which may complicate extraction.
Preserving Pulley Integrity During Removal
Vintage pulleys are often cast iron or steel and may be difficult to replace. Preserving the pulley during removal is critical. Recommendations include:

• Using a flat plate puller with evenly distributed force
  
• Avoiding hammer strikes on the pulley face
  
• Supporting the pulley from behind during extraction
  
• Marking the pulley orientation for reinstallation
  

If the pulley is damaged during removal, machining a new keyway or resurfacing the belt grooves may be possible. Some restoration shops specialize in rebuilding vintage pulleys using weld repair and lathe work.
Field Anecdotes and Practical Advice
One technician in Minnesota recalled removing a crankshaft pulley from a WD-series Allis-Chalmers engine. The pulley had no puller holes and was seized from decades of exposure. He borrowed a bearing splitter and used a hydraulic press to extract it after heating the hub with a propane torch. The key had sheared, and the pulley was slightly deformed—but he salvaged it by broaching a new keyway and balancing the assembly.
Another operator noted that the pulley on his grader had an Allen head set screw buried under grease. After cleaning and removing the screw, the pulley slid off with minimal force. He emphasized the importance of thorough inspection before applying brute force.
Conclusion
Removing the crankshaft pulley on a 1961 Allis-Chalmers D grader is a task that blends mechanical intuition with patience. Whether dealing with hidden fasteners, seized hubs, or modified keyways, the process demands careful tooling and respect for vintage components. With the right approach, even a pulley that hasn’t moved in 60 years can be coaxed free and restored to service. In the world of legacy iron, every bolt and groove tells a story—and every successful repair keeps that story alive.