Rust on the inside of main caps in rear end

[bill3rail]

Originally Posted by Mike C

I'd lightly sand it. Very lighlty. You need to make sure it doesn't lose surface area contact to the bearing race. I'd also get a piece of glass and sand the mating surface of the caps as well to slightly tighten it up.

Place glass on table, place sand paper on glass, pass mating surface of cap across. Maybe 4-6 passes on 120 grit paper.

If you use sand paper, I would use much finer grit than 120. I would go with 600 grit or finer.

Bill

[Ethan341]

Thank you for clearing that up I didn't really know what to do there. I sanded them with 400 grit and they have a nice shine now. Hopefully it works and nothing breaks.

[Mike C]

Originally Posted by bill3rail

If you use sand paper, I would use much finer grit than 120. I would go with 600 grit or finer.

Bill

The original machining marks are not that fine and I think the coarseness is designed to help hold the race from spinning.

I’m not a full time diff guy, but I have built well over 30 including installing steel caps on OEM housings. So my comments are based on some experience. But as usual, YMMV.