I am rebuilding my Brakes from a pair of ATE's I found in a junkyard. One of the calipers was stuck so bad, I had to use a huge pair of vise grips to extract it.
Unfortunately, I chewed/marred the top 3/16" of the machined piston area (no to be confused with the non-machined ridged area that sits on the top of the piston).
I still think I can still use this piston because the top 3/16" of the brake piston's machined area sits above the line where the caliper's internal seal seals the piston.
Does anyone know if I can?