If your brakes use metal pistons, they can be rebuilt, however I am not a big fan of rebuilding calipers because the cost for the piston and rebuild kits is at or near the cost of a quality rebuilt caliper from the local autoparts store. The piston (plastic on the ST) probably broke because the piston bores are pitted and corroded, so just replacing the piston will not solve your problem. Rebuild kits are OK only if your piston seals are leaking. You have bigger problems.
I replace my calipers with rebuilt units when ever I do a brake job. It cost a little more money, but I know my brake job will last and that I will have the best brake performance for the life of the pads. Never buy Junkyard calipers...They are not worth the money at any price. You can buy quality rebuilt caliper for a little as $20 to $60 a piece and you will get a 50K mile to a lifetime warranty. If the piston bores are too pitted or the caliper cannot be rebuilt safely, they don't rebuild them. I have nver gotten a bad rebuilt caliper.
I do a brake job between 45K and 50K miles and take my old calipers and receipt back and get new rebuilt calipers...The calipers may have cost me an extra $100 for the first brake job, but after that, it's free. If they ask why I'm returning them, I tell them they are sticking, and that's all it takes.
Also, you should never push your pistons back in without opening the bleed screw on any vehicle, especially with ABS brakes. You are pushing that cruddy dirty fluid that has been corroding your caliper bore, back into the ABS servos! That can result in some very expen$ive repairs in the not too distant future.
Yes, that means you will need to bleed your brakes when you finish the brake job, but it's recommended that you flush the old brake fluid out every 2-3 years anyway, so it's something that needs to be done anyway, so why not do it when you are doing the brake job?
Doing a brake job is not as easy as pushing the caliper pistons back in and slapping in new pads.... as many people would have you believe. I found that out about 25 years ago. Now I open the bleed screw and push the piston back in by hand. That allows me to feel if there is any binding or scrapping on the piston which tells me that the caliper bore is pitted/corroded and needs to be replaced. Using C-Clamps and such is what causes broken pistons like you have just experienced.
Take it from someone who has been doing brakes for well over 40 years...Do the job right and you will get many more miles out of your brake job then taking the cheap quickie way. Things that seem cheap are oftem more expensive in the end!
...Rich
...Rich
