So I thought this one through before doing it, but obviously missed stepped.

I pumped the brakes with the driver side caliper off the rotor to get the pistons to work their way out. One pops out (I have to say, it was like looking at a dog giving birth) but the other one is still there. In hindsight, I should have blocked one piston so the other one would have gone out as much as the first one - but I didn't know how big the pistons were going to be.

Now, I can't pump the brakes for the passenger side anyway, because there is no caliper on the driver side to keep the pressure up. me be lost.

well since your gonna have to bleed the lines anyway, id remove the calipers. they will definatly be much easier to work with and control off the car.
i took mine off and made an adapter that hooked into my Porta-power (hydrolic ram) and pumped the pistones out with that.
the trick, like you discovered, is getting them to both come out evenly. if you use a "C" clamp on each piston you can control them on there way out.

once out then id recompend polishing the piston and bore for a nice smooth movement.
i also ended up machining the face of my pistons to they were flat on the pads too

Originally posted by foggy45
well since your gonna have to bleed the lines anyway, id remove the calipers. they will definatly be much easier to work with and control off the car. i took mine off and made an adapter that hooked into my Porta-power (hydrolic ram) and pumped the pistones out with that. the trick, like you discovered, is getting them to both come out evenly. if you use a "C" clamp on each piston you can control them on there way out. once out then id recompend polishing the piston and bore for a nice smooth movement. i also ended up machining the face of my pistons to they were flat on the pads too

thanks foggy. polishing is something I think I'd have to get done professionally - I have no tools or knowledge how to do that. I would like to change the o-ring seal inside the caliper too - but I don't know where or even if I can get those. also, I don't know if there is a special lubricant to put back on the piston when putting them in. when one piston came out, it was covered with some kind of yellow junk

nah its really not that hard to polish. if you want a mirror finish and dont have a lathe then ya might want to take it somewhere. but mainly its just getting and rust or high points off.

the rebuild kit for the dual calipers is fairly cheep and is simple to do. got mine from advance autoparts for $15
there are no o-rings in the piston itself its designed for a metal-metal close tolerance glide fit.
only the seal and keeper need replacing and comes in the rebuild kit

as for lubeing the new pistons, nothing special just use a new bottle of brake fluid to lubricate it. just smear some on the piston right before you insert it.
that yellow gunk is contaminated old break fluid

awesome info. does the rebuild kit come with new rubber boots?

yep!
pretty much the entire rebuild kit you can see on my table
rubber boot
keeper
and slider lube

for polishing go get some crocus cloth, it's like 5000 grit sandpaper designed for polishing rod journals, I can't remember where I got it last time. in a pinch some 2000 grit will do just fine, or you can get brake caliper hones at most parts stores that attach to a cordless drill.