We had another bearing fail on the little tractor but there was a small problem: Before, when that bearing had failed, the Lutz's took the part to Mt. Hagen and the shop there had to weld something onto the part in order to pull against to take it apart. We were not exactly thrilled about the idea of having to do this again, so we set out to build a bearing puller that would slide into the 1/16" gap between the gear and the casting in order to remove it. Pictured is the result after nearly five hours of work. The basic thought was to shave down two 1/8" spring steel plates so that they would slide into place, then weld something to them that would allow us to put the whole contraption in the 30 ton hydraulic press.
Of course we started out with a much less durable form of similar design. The first one I ha just one cross brace on, which popped off without much pressure. The second attempt broke my stitch welds (or rather ripped out part of the spring steel because the welds didn't penetrate the hard steel far enough) on the horizontal pieces.
At the time I was feeling wonderful because of some bad chicken I'd had in Mt. Hagen earlier in the day, so Anton went to work grinding out welds, and re-welding one of the pieces all the way around while I laid down for an hour or so. When I came back, I re-welded one of the pieces and then we were ready to put it all in the press.
After the pressure built up to about 18 tons, we were questioning the strength of our newly rebuilt device and decided that this was enough pressure, so we broke out the torch and heated the casting up a little bit. By a little bit, I mean about thirty seconds of heat and we heard a huge "POP!" ... It sounded like a weld breaking but we were quite happy to see that the part we wanted to move had indeed started to slip off. It still took about 10 ton of continuous pressure to remove, but at this point we pumped the hydraulics as fast as we could.
That night we were on top of the world! Pretty nice to build a specialized puller and successfully use it in just a few hours... We certainly couldn't have done this at Kaiam, so it reinforced the decision to fly the part out and fix it in Mambis. I will be accompanying it back down to Kaiam on Monday!
1 comment:
Handheld bearing pullers can be purchased at any hardware store. The sizes range from simple models that work well with small toys and appliances to larger versions that are ideal for work on bicycles and smaller motorized vehicles and household tools. More sophisticated models are available from companies that supply bearings for various types of machinery.
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