I love my tractors. They allow me to accomplish so much, to reach out and change the surrounding environment, in truly amazing ways. Those benefits come with a cost though – namely maintenance. As the owner of two tractors, I have learned first hand that keeping them running is a time consuming endeavor.
When the thrust bearing on the front left axle spindle on my Case backhoe failed, I didn’t expect it to be an demanding repair: pull out the snap rings, remove the grease caps, knock out the king-pin, replace the bearing and reassemble. Unfortunately, that was not to be.
To begin with, the 2″ diameter king pin was seized to the axle spindle, making it impossible to remove the spindle from the tractor. The pin must be cut. I selected a capable saw blade from my collection and set to work with a demo saw. No problem, right? Nope. As with all good equipment, the surface of the pin was case hardened, so a standard saw blade won’t touch it.
An abrasive blade is the next option. I went back to my tool box. The question now was how to spin an abrasive wheel large enough to reach the king pin, much less cut through it. I settled for a 10″ abrasive wheel attached to a 9″ angle grinder, which worked well!
With the king pin cut through, I was able to remove the spindle and take it to a local machine shop. Several hundred dollars later, I received the spindle back. They had had to drill a large hole in the king pin before even they were able to press out what remained of the pin.
With the spindle removed from the axle, I was able to inspect the yoke more closely. I noticed that the needle bearings on the lower arm of the yoke had completely disintegrated, causing the king pin to wear out a large swath away from the hole in the arm. Big problem…but can be fixed, right? Just build up some weld beads in the hole and re-machine? Not quite. The axle was cast iron, which meant that it couldn’t be welded with standard processes or common filler materials.
Somewhat discouraged, I went back to the drawing board and began to research the best way to restore my tractor to operating condition. A new axle was $2.5k from eBay. I didn’t feel to good about that. The tractor isn’t worth it. I pulled the axle off the tractor and took it down to a welder. The welder puffed a cigarette and told me it would run about $2k to get it built up. I shook my head. As I turned to go, he offered $1.5k. I politely explained that I would need to think about it because I could purchase a new axle for $2.5k and that if I took him up at $1.5k, it would still likely need to be machined back to the proper hole size for the bearing. Both operations together might cost more than a new axle. He nodded understandingly.
After reading several different sources, I finally settled on a plan that I felt might work. I purchased a pack of “77” filler rods from Muggy Weld, specifically intended for use on cast iron. I soaked the rods in water, pounded, and wire brushed them to remove the flux coating, and then used them with a Tig welder to build up the worn area on the axle yoke. (I preheated the yoke area and side of the axle for about 15 minutes with an oxy-acetylene torch.) It took several afternoons of careful work, but in the end the rods worked well and the buildup was complete.
The next requirement was to bore the hole back out to it’s proper size for the bearing. For this task, I used a 2-3/8″ Milwaukee “hole hawg” cutter. I had found a damaged cutter on eBay for only $20 (~8% of the cost of a new cutter) and thought it might still work for reaming the hole, especially as the filler rod is softer material compared to the cast iron. After the cutter arrived, I realized that a special adapter was necessary to drive it. Not wanting to spend any more money on the project at the moment, I cut the long part of the “L” off of a half-inch allen key and welded it onto the cutter.
The modified cutter wasn’t pretty, but it was functional and it worked well, even though one of the carbide cutting teeth was missing. I slowly cut away the weld build-up with the cutter attached to a right angle drill. The hole was reborn. After touching up the hole with a flapper disk, I tapped the bearing in for a test fit. It was close to perfect!
Having a tractor to take care of so the many jobs on the ranch is a blessing. They are a must have on any land development project and I’m thankful for them, in spite of the maintenance that they require at times to keep them operational. For my tractor, it still took a few hours to re-assemble the axle with the spindle and re-install it on the tractor with all new bearings and a new king pin. The rest of the re-assembly went smoothly and my tractor was restored to operation after a months’ long hiatus.
*Image source: https://www.mycnhistore.com/us/en/casece/na/light-equipment/loader-backhoes/d/case-construction-king-loader-backhoe/steering/front-axle-and-spindles/cn/10BE3E73-8FBF-E111-9FCE-005056875BD6
