Hey guys, Came across a 2002 773 with about 5000hrs on it. Only severe issue it has is a snapped axle and the end of the axle tube is damaged. Did some research and found a company called Original Mechanic that sells a repair kit, basically cut off a certain amount of the tube, and weld on a new piece that tapers down to factory spec size so you use all original bearings and seal. Picking up the machine for about $2k. Will also need to cut out the seat pan, weld a new one in, get a new bucket, current one is rotted out. Other then that, Ive been able to test out the machine, starts right up, throttles up and down, bucket raises and lowers, and curls. Machine turns left/right and I can move it a little, didn't want to push it with only having 3 wheels on it. Can anyone comment on doing this axle tube repair? Thanks JR
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flyerdan
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Speaking as someone who has scabbed a lot of round stock together, the biggest issue will be clamping it so it won't wane in one direction. I would use a couple chunks of "C" channel to line them up and put a tack top and bottom, then reposition the clamping rig and do two more side to side.
Length will also be critical, so I'd probably put the bearings, axle and sprocket on to set the length and help with the lineup. Keep the chain off for this of course, another benefit is that you can rotate the hub and feel for any area where it gets harder to turn, indicating that something has pulled and put the bearings in a little bind. Easier to deal with at the tack stage than later.
When you weld it up, heat the whole area up with a rosebud; if you can get a helper to play a little heat on the opposite side you are welding it should help to even out the heat, and reduce shrinkage pull in one direction. Since it will be hidden behind a tire, I wouldn't even bother grinding it down for looks, just paint it and call it good.
Length will also be critical, so I'd probably put the bearings, axle and sprocket on to set the length and help with the lineup. Keep the chain off for this of course, another benefit is that you can rotate the hub and feel for any area where it gets harder to turn, indicating that something has pulled and put the bearings in a little bind. Easier to deal with at the tack stage than later.
When you weld it up, heat the whole area up with a rosebud; if you can get a helper to play a little heat on the opposite side you are welding it should help to even out the heat, and reduce shrinkage pull in one direction. Since it will be hidden behind a tire, I wouldn't even bother grinding it down for looks, just paint it and call it good.
There was a member that did this a good 10 years ago with great success. As mentioned, length is critical, but can be adjusted if you have a lathe and cut the washer that holds the sprocket on the axle, so a little long, a little short is not a huge deal.
His new axle was cut the same diameter as the OEM BUT he also had a section machined to slide over this section. I can't remember if it was split, to allow you to weld the tubes together, then lay these two halves over and weld it on for extra strength. But, it did the trick.
I have actually done this. I had a Bobcat 873 that had a bad outer bearing that chewed into the bearing race and the outer part of the axel. I bough a new axel seal, bearing race and a piece of pipe with the same outside OD of the axle tube. I took all the parts to a machine shop so they could cut the ID to fit the new bearing race and seal. I then measured how long I need the new piece to be and had the machine shop cut the new machined piece to length. Before I weld the new piece on I cut the damaged part off the axel tube as square as I could. Once I got all the parts back to my shop I tac welding bar stock in three places on the out side of the machine's axel tube to make sure the new machined piece would fit squarely. Make sure all your measurements are the same as the existing axel tube so your axel will fit properly, then weld it up. Hope this helps.
