For the purpose of safety, and safety alone, DO NOT rebuild the
brake calipers, REPLACE with two new calipers. Not everyone
has the skill to correctly rebuild a brake caliper and that is why so
few shops do it. You may not care about your well-being nor
the value of your car, but faulty brakes could injure someone else
and cause them losses. Again, it takes knowledge, skill and real
insight to restore old calipers, so do not try to play expert with
this equipment. Buy brand new calipers in pairs and be safe.

You have been warned.