[ERE]

Here is a long shot. I am where I can't go look at my tractor, and of course I can't see yours, but I have replaced mains (and con rod bearings also) in one car and one old International Farmall Cub without pulling the engine off. It all depends on if your pan gives you enough room to get at the bearing bolts, and how the bearing shells are pinned to the bearing housing. In my case I loosened all of the bearing bolts just a little so the crank dropped down a few thousands. Then working one bearing at a time so the crank was always supported, pulled off the cap, rolled out the upper half and replaced both halves. Once I had one in and had it helping to support the shaft I went on the the next. In my case, the surface of the crank was still undamaged so there was no need to work on it. That should be the case so long as there is still some babbit material on the bearing halves and it hasen't gone to hard iron rubbing on the crank shaft bearing surface. The key is that the bearing construction has to be such that the upper half bearing shell isn't pinned in. In my case the lower half was pinned (and that prevented both half shells from rotating) so that it worked fine. You might be able to tell from looking at the bearing in the dealers parts, or someone who has had one open (Rick maybe) might be able to chime in. Not exactly the recommended way to do it, but it worked fine for me and could possible work in your case.