Stuck pistons

Hi all

Giving my brakes (Hayes 9’s) an overhaul, and i can’t get the pistons out – they’re stuck solid, which probably explains why they haven’t been working properly. Tried the compressed air approach, but still no joy, they’re not budging on either side! Anyone got any bright ideas? Though about heating them up, but is that going to damage the seals? I’d like to avoid replacing them if possible

Cheers

i don’t know hayes, but try popping the caliper on its side, stuck piston up, (its a good idea to do this on a piece of wood so you do not damage the downside of said caliper) and tap the outside of the caliper with a hammer (poss use a drift to save damaging caliper) combo.

worked for me with a sticky hope mono mini piston the other week.

p.s. if it does’nt come out, it may still jar the piston enough so that air might get it out.

On my formulas I had to fill them with fluid then wedge one of the pistons in place whilst I pumped the lever to loosen the other one, then wedge it whilst I loosened the remaining one.

Copied and pasted from another thread…

How much air pressure are you using, it took 120psi (from a track pump) to blow out some pistons from a set of Hayes the other day, I had to seal of the small hole with a bit of rubber and a clamp to generate enough force to blow the pistons out. Wrap some rag around the caliper to stop the piston coming out like a bullet..

Did they work at all? If they did, bleed them again and just use the lever to push them out.