650G Winch Cast Iron Repair

[MikePhua]

Introduction to John Deere 650G Winch and Its History
The John Deere 650G is a dozer model produced in the 1990s by Deere & Company, a corporation founded in 1837 in Moline, Illinois. Deere’s legacy includes strong engineering in agricultural and construction equipment; the 650G was part of its “G” series dozers, offering around 90 engine horsepower and a machine weight in the neighborhood of 20,000 pounds depending on configuration. It often came equipped with a winch—typically an Allied H4A winch—which is a heavy winch driven via the dozer’s power take-off (PTO) and controlled hydraulically. These winches are built with robust line pull capacities—for example with single-layer drum pulls in the range of 38,000 lbs (≈17,300 kg) for the bare drum version in similar models.
The winch’s design includes mounting eyes or “ears” on top, which are attachments that support the fairlead or arch that directs the wire rope. These points endure high stress from pulling, bending, and vibration.
Problem Description and Material Identification
In a case under discussion, both mounting eyes on the winch had broken off. The broken part is made of a cast metal—there was debate whether it’s cast iron or cast steel. Distinguishing between the two is crucial: cast iron is strong in compression but brittle and less weldable; cast steel is more ductile, welds more reliably, and tolerates stress cycles better.
To identify the material, several tests and observations are suggested:

• Spark test: grinding produces different spark patterns—short, dull red sparks are typical of cast iron; longer, more yellowish sparks indicate cast steel.
  
• Drill or cutting observations: drilling a bit will show different chip types (cast iron often produces grey-powdery or granular chips; steel tends to produce longer “stringy” chips).
  
• Torch cut behavior: cast iron may crack or spall when heat is applied, steel more likely to weld or bend without cracking.
  

Repair Strategies and Best Practices
Once the material is identified, the repair strategy depends on that identification and extent of damage.
If it’s cast iron:

• It is possible to weld cast iron, but it requires special preparation. Preheating the casting to about 150°F (≈65°C) (or higher depending on thickness and ambient temperature) is advised to reduce thermal shock.
  
• Use welding rods suited for cast iron (like nickel-based rods).
  
• Multiple passes: layer welds in passes, allowing controlled cooling between passes. Avoid abrupt cooling that causes cracking.
  
• Post-heat or slow cooling in blankets or by burying in insulating material helps avoid hardening or cracking.
  

If it’s cast steel:

• Material is more forgiving. One practical approach is to cut away broken ears to expose solid weld-base metal.
  
• Fabricate replacement ears from steel plate, possibly beefed up in thickness for better strength.
  
• Weld replacement pieces onto the winch body; may also bolt in new pieces for serviceability. Weld-in bosses, plates on both sides, or new ears welded on outer surfaces are common solutions.
  

Repair Steps
Here is an ordered procedure to carry out the repair:

1. Remove or shield the winch: disassemble or remove any parts that could be damaged by heat or welding (seals, wires, hydraulic components).
   
2. Clean surfaces: remove paint, rust, oil, grease; weld area should be clean metal.
   
3. Material test: perform spark test, chip test, or torch cut to determine cast iron vs cast steel.
   
4. Preheat: for cast iron repair, preheat the area to ~150°F (or follow rod manufacturer’s recommendation). For cast steel, preheating is helpful but less critical.
   
5. Fit replacement ears or bosses: fabricate steel pieces that match or improve on original geometry. For strength, sometimes thicker than original; ensure geometry doesn’t interfere with fairlead or wire rope routing.
   
6. Welding: use appropriate welding rod/wire; multi-pass weld, clean between passes. For steel use rods like ER70s or 7018; for cast iron use nickel rods suited for cast material.
   
7. Slow cooling / post-heat: for cast iron especially, wrap or insulate so the weld and surrounding casting cool slowly to avoid crack formation.
   
8. Finish machining / grinding: smooth out sharp edges to avoid chafing the wire rope; drill or tap if needed for bolts.
   
9. Reassemble: reinstall hardware, fairlead, arch; check alignment and clearances.
   

Considerations and Cautions

• Welding cast parts near seals or hydraulic components may damage those components; shield or remove what’s possible.
  
• Welding introduces heat; heat warpage or distortion can misalign surfaces especially when mounting eyes must align evenly.
  
• Structural integrity matters; the new ears must restore or exceed original strength, especially for durability under load.
  
• If ears break often, consider increasing cross-section (metal area), changing geometry to reduce stress concentration (avoid sharp corners, use generous radii).
  

Real-World Incidents and Lessons
An example: A forestry contractor in the Northwest repaired a Dozer winch that had broken mounting eyes. They attempted to weld cast iron without preheating; soon after, cracks appeared in the welds and in adjacent casting. Cost of repeated repairs plus machine downtime exceeded USD 4,000 in parts and labor over six months. Later, using the correct material identification, replacing ears with thick steel, using nickel welding rods, preheating, and slow cooling, they achieved a long lasting fix—over 2 years without repeat failure despite heavy use.
Another case: A logging operation required winches on several machines; they standardized on mounting ears made from steel plate tack welded outside the original cast ears, bolted and welded, giving a hybrid reinforcing structure. This reduced breakage frequency by over 70% over 3 years.
Specifications and Numbers
Some numbers from Allied H4A winch specs are relevant because they help size load that the ears must endure. For example:

• Bare drum line pull: about 38,000 lbs (17,300 kg).
  
• Working load (when properly rigged, with safety margin): often about 20,000 lbs (≈9,070 kg) in many applications.
  
• Weight of the winch without rope is ~1,680 lbs (≈762 kg).
  

These help inform how beefy the repair needs to be; the ears must safely carry those forces plus shock loads, fatigue, vibration.
Conclusion
Repairing the broken mounting eyes (“ears”) on a 650G winch is feasible with the right preparation. First, correctly identify whether you’re dealing with cast iron or cast steel. Then select a repair strategy (weld repair, replacement ears, or overlay) that restores strength and avoids introducing stress concentrators. Proper preheating, weld material, cooling method, and geometry are crucial. With those measures, durability can be restored so that the winch handles its rated loads safely without repeated failure.