borked front brake!

Well as the title says really i’ve got a set of xt m775’s and no matter what i do the front brake makes a hellish racket i mean this thing could wake the dead!
I’ve tried bleeding it several times, i’ve changed the pads, i’ve swapped the lever over with an older xt set and i’ve swappped the caliper again with an older set of xt’s and nothing works.
i reckon it’s time to bin it! what say you?.

So, different pads, different lever and different caliper, essentially an entirely different brake, and it’s still doing the same. Perhaps you should be looking at the rotor. It could be warped or possibly contaminated (in which case the new pads might be contaminated too). If you’ve got a spare rotor lying around it might be worth a try (possibly with fresh pads in case the installed set are contaminated).

yeah i forgot to mention that i tried cleaning the rotor and several different pads to no avail, all i can think now is that both lever and caliper are **** or my bleeding abilities are less than adequate but i’ve bled brakes before with no problems so….

Is the problem that it’s making so much noise? Or is it actually not working?

Torch / sand the rotor and put new pads in. Also, organic pads are quieter if you don’t mind changing pads a bit more often.

the thing is when i put my old xt’s (m765 i think)back on the noise went away so i don’t think the rotor is the problem. there was some loss of power but pumping the lever brought it back for a while.

calliper seal failed allowing a tiny bit of fluid onto the rotor?

it’s a possibility but i’ve been keeping an eye on the whole brake for leaks and can’t see any! still i may be wrong. Anyway i give up now time to accept defeat and take it to the lbs.

Stupid question, but is the mount square and true? Don’t know if the forks are IS or post mount but is it worth getting the mount faced? Or indeed is the caliper’s mounting face square?

I’m with TJ although after my recent experience with SLX brakes I have a hatred of recent shimano brakes.

Both my front and rear calipers have developed leaks within 7 months from new. 🙁

Currently negotiating warranty but I’m so unimpressed I just want rid and to try a different brand. Shame as my old deores were bombproof.

i’m starting to think that’s why shimano have redesigned the xt and xtr brakes to something similar to the old 755 and 765 type.

I’ve had a similar issue with my xt m775s. I’m fairly sure it’s a problem with the calliper seal/piston as I discovered an oily residue on the back of the pad which must somehow work its way on to the pad surface. I’ve had to resort to taking the wheel off and pads out when not in use and sanding the pads/cleaning rotor before every ride. I only seem to get the noise in the final 15% when pulling on the lever though and it seems to improve during the course of a ride.
Jonb – Any idea what the length of warranty is on these?

12 months?

Not really up on this but don’t things have to be fit for purpose? THere were heaps of complaints when it was cold as apparently that makes the problems arrise quicker.

would like to give a massive big up to my lbs known as Primera in poole dorset! i took my borked front brake in (the whole bike actually)yesterday after all that faffing about and they sorted it.
it was contamination of the disc and pads after all that so it just goes to show how invaluable these guys can be and how you can be wrong even when you think you know pretty much most things about a bike, i thought either the lever or caliper was gone and i was wrong so thanks a lot dudes.