Crokus cloth is a lot finer than 400 grit. I would not use a wire brush any where on the inside pieces of the calipers. Clean the insides and piston with a lot of break cleaner/aceatone and a rag/soft nylon toothbrush. If they are real dirty let them soak for an hour. After cleaning them look at them real good. If there are any scratches or rust take a green scotch brite pad soaked in brake fluid and real lightly hit just those areas. Clean everything back up with brake cleaner and then oil the piston and cylinder with brake fluid. Be real careful when you put the pistons back in not to nick the sides. Go straight in. Don't forget to put new bleeders on.
As far as the outer seals go, just take your time and if you tear one or two putting them in they are cheap to buy. It's all in the process of learning.
Let us know how it went or if you have any other questions.
Last edited by dimitri; 12-07-2010 at 11:51 AM.