I have fitted new pistons and seals to a set of juicy 3 brakes, bleed them and they are working well - but!
On the first squeeze of the lever they feel great, nice and progressive to a real solid feel at the end. Let them go and they release the disc fine, the wheel spins without any drag - but the pistons don't go all the way back immediately, leaving the lever 'rattling' and loose. On next squeeze you have to take up this bit of slack in the lever, then it all works as before. Leave it and go back an hour later and it's back to normal - the pistons seem to have slowly gone back that little but further and taken out the loose play.
Both brakes are the same!
Any thoughts?
Any thoughts?
Bin them and get some decent brakes! 😉
Sorry, not terribly helpful!
Both the same? Rules out the obvious culprits - lever return spring or master cylinder return spring being broken.
Sticky seals then - lube with brake fluid / red rubber grease.
Might even just be he new seals being very tight.
I used red grease when I assembled them, but I guess they might ease with some use. Both having the same problem might be a red herring - they were both in a shabby condition, so maybe they do both have broken springs - something to check anyway.
.....and I know replacement would be an easy option, but I am trying to fix a mates bike so that he can keep riding!
Has anybody lubed the lever pivots recently? Some indiscriminate use of spray lube may cause the M/C seals to swell and cause similar problems.
I've asked and apparently yes - GT85 on a regular basis, which I understand is a no no for juicy levers for the reason you point out - swells the MC seals. Could be the answer.
Probably is then, unlikely to be the spring broken or it wouln't return at all. Make sure you remove all traces(use brake cleaner) before you replace the piston/seal assembly, or it'll do it again.
I've had this on two Juicy 3s. Both times it manifested after bleeding them for the first time, once with new pistons and seals, and once without. I was using DOT 5.1 and I've read somewhere that Juicy 3s come with DOT 4 in them, so I have vaguely wondered if that was something to do with it. 5.1 is supposed to be okay according to the specs.
I never figured out a solution. I had tons of other problems with my Juicy 3s, and slow-lever return wasn't a big deal in comparison with the sticky pistons and persistent shrieking, so I just bought something else and chucked them in the spares box.