Here's an interesting repair I helped with last night.
A good friend has a machine shop, one of the best in his area. Because he will deal with the walk in work, he gets a lot of farmers, excavators, and other small time repair work. They've got some good welders on staff, but they asked me for my help on this one.
This Case backhoe had a pivot boss shear off. There is a pipe connecting the two sides of the front bucket arms going through the hydraulic tank on one side and the diesel tank on the other. The tanks are part of the chassis and not removable.
The bearing boss on on one side had broke loose from the pipe inside the diesel tank, and then cracked the outside of the tank right around the weld due to the forces from the loader arm.
My buddy's shop machined a sleeved bearing boss that would slide inside the existing pipe, as well as a new flange to seal up the tank.
We had to weld the new boss into the pipe, and then slip the flange over the boss and weld that to both the tank wall and the boss.
The inner pipe weld was grooved out, and had 4 passes with 70S-2, and the outer plate and boss welds were each 2 pass welds with 70S-2.
We chose to TIG this repair for a couple reasons. First, there was some seriously tight fits between the weld and the tank wall, as well as up against the cab. No way a MIG gun was fitting in there, and a stick weld would have been quite difficult as well. I would have had to bend and contort the electrode to fit in a very tight gap that I couldn't see. The flange weld was a lot more roomy, but still kind of snug up against the cab. TIG was the easy way in this instance. We already had pulled a window, we didn't want to pull the cab.
Second, we didn't want any spatter or slag getting into the tank to cause problems down the line. This backhoe is owned by a guy who takes the utmost care of his machines. This thing is like, 30 years old and still looks fantastic. He made a point to have us try not to scratch the paint or get spatter on the windows.
Looks pretty straightforward, but I'm here to tell you, that was a bit of a tricky weld on the bottom side of that pivot boss with the torch jammed up inside the tank and my head wedged inside the cab.
My buddy did a great job on the machine work, that outer flange has an angled bore, so the plate lays flat on the tapered fuel tank and still fits snug up on the pivot boss.
Yeah, most
real heavy equipment repair guys could probably have gotten this done with 7018 upside down in a mud hole out in the oil patch with one hand or whatever, but this is what the customer wanted and they are happy with the results.
Thanks for looking.
Nice piece of equipment.
