i had thought that yesterday would be nice day to press a piston back into the caliper and reset the venting, do a little brake bleeding, and be done with it. such naivete must amuse you gurus out there...
anyway, Dino (dinomium) came over to assist and act as technical consultant . i plied him with salami and goat cheese on garlic bread sandwiches (alas, i could not offer him a brew), coffee, and we got started. all went according to expectations; piston went back in smoothly , etc. then came time to adjust venting. Dino pressed on the brake. the pistons actuated. Dino released pressure on the brakes. and the pistons stayed right where they were . rotor no move no more. then that little ray of sunshine that is Dino says, "hmm, it's time for a caliper rebuild." i think i heard thunder punctuating his statement.
so, rear caliper rebuilds are in my immeadiate future. i will, when the time comes, be requesting input. and while i am in there, maybe i can do a couple other things...