Problem retracting rear brake caliper pistons.
 

So, i am installing rear pads and rotors on my car for the first time. I have done the first ones before with no problem. I removed the 14mm cap on the rear caliper and i put in my allen wrench and started turning it counter clockwise. The piston was not moving. I could feel the hex screw in there but nothing happenned when i turned it. I eventually turned it so much that it came out and now it wont go back in no matter how much i turn it. Did i fuck up my caliper?
Thanks in advance,
Wes

hmmmm.....
You did what? On the rear, I always turn the actual piston back with some pliers.

its probably seized. the rears do this a lot.

+1 on Brainey. About two years ago I rebuilt all four of mine (just cleaned up and used new seal kits) and while none were actually seized, the pistons in them were pretty grungy. There was some surface rust and general funkiness on the pistons themselves. Some 2000 grit sandpaper and a lot of brake cleaner had everything looking good as new.

Given the age of your car, I'd suggest that a caliper overhaul might be in order. In terms of parts it's very inexpensive. Caliper overhaul kits are $50 front, $40 rear from Rozenthal (each kit does two calipers) and new sliding pins will run your about $20 for a full set. Doing the rebuild is not complicated, basically you're just cleaning everything up and replacing all the rubber bits. The only tricky part for me was getting the piston seals back on- I ended up using a pair of dental picks with the tips dulled down. While you're in there will be a good time to get that adjuster back in, too. It sounds to me like you pulled out the piece with an allen socket on one end, and splines on the other, yes? It's not hard to get back in, but it does have to be lined up properly.

Then it's just a matter of re-assembling everything and flushing out the system thoroughly with new fluid.

hmm, would it be better just to buy new calipers?

$350 for new calipers vs. $90 and a couple hours' time to rebuild. It's entirely your decision.

I just "refreshed" my brakes, but didnt do an actual rebuild..
Took off all calipers, hit them with ton of brake cleaner & had a couple different sized wire brushes in there...also added ss lines, better pads, lots of lube, new rotors, and couple coats of paint, and some motul..

+1 about how much gunk/surface rust gets in there and how clean they looked after just 5min with a wire brush...I got the calipers/pistons looking practically new again...

I say do it yourself

edit: my driver side rear also seized, but with brake cleaner/adjustment screw it popped loose...this was what got me started on doing the brakes initially

well, i got it to retract, i put one of the old pads against the piston and cranked with a clamp. this was after i had unscrewed the adjustment screw. now to figure out how to get that rear rotor off.

if the piston/bores are all gunked up you may get uneven wear on your new pads. i'd keep an eye on that when you do get everything back together.

if your rotor is just stuck try putting two lugnuts back on (just few threads will be fine) and smack the backside of the rotor with a rubber hammer.