I am rebuilding the brakes on my 1988 GTU and have gotten stuck at the front because one piston will not budge. I have a rebuild kit and new caliper pistons and cannot get it out, and have tried compressed air, rotational pressure, prying it up with flatheads... It is for the front driver's size (front left), I can only find passenger side remanufactured ones. What should I try next? Are there any tools that I should look into? I would love to get it out and use the rebuild kit and pistons that I got if possible.

the other 3 that are not circled pop out just fine, I just have them pushed in in this photo

I know it was mentioned here as well, but did not see a solution or outcome: https://www.rx7club.com/2nd-generati...piston-833565/

 

Have you blocked the other three tightly so they don't budge, and then add the compressed air? How much air pressure are you using? I had one that was a little sticky, and the other three decided to let loose first. I had to shim wood blocks between the others to prevent them from moving and finally the stuck one popped.

 

Thanks for your comment.

I have tried blocking in all of the other pistons and shooting 90-150 psi of air but it didn't budge. It worked on the first caliper where the last piston that was also stuck, but not this one.

 

Maybe try to fill the caliper with some penetrating oil and let it sit for a bit? The usual culprits would be either rust, pitting, or possibly damage. The penetrating oil might help.

You other option would be to extract it with a bit more force... maybe drill a hole into it or well a nut to it and use a slide hammer?