In my opinion, the bolt holes in the final drives take the hardest beating. I doubt that any repair will take those you describe back to original as good as new.
For the torque tube holes, a couple of mine had been enlarged to 3/4-10. It so happens that the tap drill for 3/4-10 is the same as for the coil insert for 5/8-11. So I simply tapped for the 5/8-11 insert, cleaned insert and hole with lacquer thinner, put JB Weld in the hole, carefully installed the insert (messy process), put more JB inside the insert and let it all cure for 48 hours. Then drilled out the excess JB with standard tap drill for 5/8 -11, tapped with standard 5/8-11 tap for the best possible threads and tightest possible fit for the insert. They have worked well thus far. The torque tube holes are deeper and open on the back, which helps with what I did. With the previous tapping to 3/4- 10 thread, retapping to insert 11 thread results in some areas with very shallow threads, but the starting threads are rather good. For the torque tubes, the boss is large enough to drill and tap for 7/8-9 external thread insert with 5/8-11 internal threads. That is my Plan B should it become necessary.
The shallow blind holes on the final drives do present more of a challenge. Welding would be my plan D, after trying to find replacement finals as Plan C.
I do have one Cub where one of the holes in the final was broken and expertly brazed before my ownership. But the 5/8- 11 was drilled crooked and slightly off pattern. So I built a drilling jig, redrilled for the coil insert and installed it. The hole is now in the correct position and alignment. It has worked well since then. I think that the insert helps spread the stress on the built-up brazing.
Keep all the implement mounting bolts tight. Loose bolts increase the stress on the holes when using implements. Keep a bolt in every hole at all times to help keep the threads clean and keep out insect nests. Use a cordless drill with 3/8 bit at slow speed to clean out packed debris on the bottom of the final drive holes. Let the drill cut the debris, not metal.
Last edited by Bus Driver on Sat Sep 29, 2012 8:50 am, edited 2 times in total.