pistons on front brake arent moving out, best way to clean/remedy them?

Take the wheel and pads out, gentle pump the pistons out and clean the exposed surfaces with a cotton wool bud dipped in Shimano brake fluid.

I’d swap them for some LX brakes if I were you… 😉

As Dibbs said but I like to push the pistons in again and repeat to remove the dirt that the fluid picks up.

take the pads out, use WD40 which disolves oil and shite, clean, pump leaver and repeat, worked for me, one piston stuck in so did the above and hey, good as new – just make sure you get rid of all the WD40 once you have finsihed, once the pistons are fully pumped out before falling out, I put a very small blob of mineral oil on the pistons, again once retracted, wipe away the access oil

Just did mine, oil all over the dining room floor. One of the pistons came all the way out…lol. Cleaned the pistons and the cylinders, put them back together, topped up the res, got all the air out and they are working sweet now. I can now leave the oil on the floor for the missus to clean up…:-)

I have XT 4 pots and they need the pistons working back and to a few times every now and again. Just once won’t do it, 8 or 10 times seems OK. You can leave the pads in place but just make sure that whatever you use to push the pistons back in doesn’t score the front of the pads. Oh, and try and make sure they don’t come all the way out……..

Get a can of CRC NF contact cleaner.Its a electronic cleaner in a can and is brilliant.Srays on,evapourates off and leaves no residue.Ive been useing it for years and find it fantastic.Pump the pistons out and give them a good dose of spray.End of problem in 2 seconds.Can lasts for ever.

lol @ stu, yup those buggers worked problem free……enjoy

one piston refuses to budge, its hardly coming forward at all-any ideas?

Clamp the other piston in place – use a small adjustable spanner or something similar to hold the moving piston then pump the lever and that should eventually force the non-moving piston to move. Then do the clean-with-mineral-oil thing. Repeat as necessary.

It’s a recurring thing with the new XT brakes – they’re fantastic when they’re working, tons of power and modulation but they seem to be plagued with sticky/lazy piston problems. 🙁

My Juicy 5’s seem to have the same problem – one piston clamping the pad to the disc. Presumably exactly the same process?

Presumably exactly the same process?

Same process but use DOT 5.1 fluid to clean the pistons on Avids.

best keep an old set of pads for these occasions
saves damaging the good ones with whatever you use to lever the pistons back
a bit of metal or an OLD disc and a pad in the functioning side will stop the good piston coming out too far keep applying the brake till you see the stuck
piston start to move then try to clean the crap off it
failing that its a piston out job

ok did all that seemed to work but now neither pad moves when pump the lever. *sigh*

pad meaning piston obviously

How old is it?

m775, not v old. im missing somethin obvious i reckon but need a brain kickstart

Rebleed? Has any fluid leaked out?

How old is not V? Under a year?

a year maybe, they were moving earlier its just when i went back to it neither piston is moving while lever is pumped

service time, before it all goes tits up

yup thinking the same but cant figure why one would be fine one sticky then they both clam up *sigh*