Used Brake Caliper Check List:
1. Inspect the caliper threads for rust and wear. Inspect the hardware threads for rust and wear. Clean caliper and hardware threads if necessary. Remember that the caliper is made of aluminum and the threads are very easy to strip.
2. Inspect the piston dust boots for signs of wear.
3. Inspect the piston seals for leaks. Press on the pistons, they should move.
4. Inspect the bleed screws. Make sure the threads are clean and functional, and the passage is clear.