Hey, I am having some issues regarding my rear disc brakes, moreover on the caliper brake piston. I've done some reading on here and while the info I found is helpful, I struggled to find a forum from the last decade, so I believe the info may be a bit dated? As I understand I cannot use a c clamp to push the piston back in as it is threaded due to the ebrake. However every form makes mention of a gm "special tool #J-23072" which I cannot find outside of eBay for 100$. They also say to use needle nose pliers and wind it back in, which I am struggling with as the piston will not give at all. Any help or links to more info on the topic is well appreciated!
'87 firebird fourmula 305 tpi j65

 

No need to buy a GM unit, one of these will work just fine, harbor freight also sells them: https://www.homedepot.com/p/Capri-To...hCowA5UtLiZxKs

 

Honestly most of these calipers have seen better days. When they were new they weren't good to start with. I would buy 2 reman calipers and go back to enjoying life. You might not find much joy playing with those calipers.

 

If you're wanting to keep it original, you'll probably have to have them rebuilt.
if you don't need original, update to the 89 pbr caliper setup for your 9bolt. (89 is a 1 yr only bracket with 1st and 2nd design for bracket)