NEVER use brake cleaner on the pistons! It WILL swell and damage the seals.I have a theory but need an answer to this question first.
In cleaning my calipers, when I first removed the pads and used my toothbrush (tastes terrible now) on the pistons, I sprayed brake cleaner. The pistons move in and out fine. What I didn't realize, until I lubed the pins today, is that there is such a suction on from the rubber seals to the pins that it was quite hard to pull the pins out of the seals (these are the slide pins allowing the caliper to "float").
Is there supposed to be such a tight seal/suction? If not, I believe this may be why my brakes are staying so tight after releasing them. My theory is that the brake cleaner caused the seals around the pins to swell.
Can anyone confirm/deny this theory?
Can anyone describe what their pins and seals are like?
I use clean brake fluid and a toothbrush, or simple green. I've seen people use windex also.
After the pistons are cleaned with brake fluid, they should push in and out with little effort.