Best way to repair stripped out 7/8" threads

Couple things here, if that bolt is a grade 8, it needs minimum of 1 1/2 to 2 times the diameter of full thread engagement in cast iron for it to realize it's full potential, the factory didn't drill the hole that deep for enjoyment. No epoxy will hold that sway chain load, think of a 500 lb. brush hog swinging on the end of the arms, even a couple inches of travel and it's a 500 lb. hammer swinging on the end of the arms. There are several options for an effective repair as mentioned above, threaded inserts, Heli-Coil inserts, or drilling and tapping oversize. One other point to consider is that fine threads are stronger than coarse threads and fine thread taps twist in a whole lot easier. As mentioned above, to keep the hole straight and centered, I would grind a drill with a pilot at least an inch long, go as deep as possible and finish with a non piloted drill to full depth, and probably do the same with the tap at least to get it started, but I have a machine shop and a cutter grinder to make short work of the tools required, not to discourage you, but this could go bad fast if you're not entirely sure of your abilities and could run into bigger money to get it right if you make a Boo Boo. I wish you the best of luck with your decision and the repair, that 7700 is a fine tractor, even if it is blue.

Tbone95 wrote: However, I don’t think I can think of a tractor where the chain keeps something from swinging out too far. The ones I’ve seen, when hitched to a brush hog or plow or whatever, the lift arms are sucked in and keep from swaying by the insides of the arms coming into contact with the rear end housing and usually a plate of some sort. The chains limit movement when free and unhitched.

I forgot an important item, when drilling and tapping cast iron, ALWAYS machine it dry, any kind of lubricant will do nothing but cause it to work harden and you won't be drilling it with any tool known to mankind, especially using hand tools. Cast iron is full of free carbon also known as graphite, so it has it's own built in lubricant. As for the debate on fine versus course threads, fine threads are always stronger, but not always practical, especially in a production setting, a 1" hole isn't that hard to hand tap, but a fine thread tap is much easier to twist in, I think either course or fine would be suitable for your application, properly torqued with lubricant, loc-tite shouldn't be required, but if you choose to go that way stay away from the red stuff, blue or green with everything clean and using the proper primer, they aren't going anywhere.

I remember our Massey, it had brace bars that attached farther out the axle to limit sway for certain jobs. Just kind of odd that it would rely on jerking a chain like that.....but it is what it is.

I would be looking into what Jim just posted. Makes a whole lot more sense than jerking a chain bolted into your cast rear end with all that weight and momentum!

Perfect!

Nicely done!