Screeching XT brakes. Possible leak ?
What type of pad material have you tried? My earlier thought was glazed pads, maybe not bedding them in or putting some early heat cycles through them, do they look contaminated (however that may manifest?), tried sandpaper? I presume you may have already gone through this process?Posted 3 years agoslackaliceMember
Bedding in? Some say yes, some say no. I do both 😀 I’ve found it handy to put sintered (metal) pads through a few increasingly harder stops and have found the brakes to be more responsive subsequently.
Ive only bothered bedding in resin or organic pads, when they’ve not felt ‘right’ after fitting them.
Either way, you’ll find it good practise to remove the pads from the callipers when bleeding and then use some brake or carb cleaner spray (or isopropyl) on the disc afterwardsPosted 3 years agophiiiiilSubscriber
I swapped both calipers on my XT brakes the other year because of similar symptoms; I suspect the seals fail in the cold and start slowly leaking. I think there was a thread on here at the time with a few others coming to the same conclusion. As you can’t get replacement seals all you can do is replace the entire caliper…Posted 3 years ago
My lads Norco has inherited my old XT brakes, I bled them and fitted new pads when I installed them and the rear developed a really loud screech. I presumed I spilt fluid somewhere so cleaned the disk etc and fitted new pads again. Within a short distance it has the same problem.Posted 3 years ago
I think it might be leaking on the caliper, is this common ? An easy fix ?gonzyMember
if you need to check if the caliper is leaking then take the wheel off and put some tissue on the rotor and the re-fit the wheel. then pull the brake lever and tie it off in that position and leave for an hour or so. if there is a leak at the caliper thats getting onto the pads/rotors then it should show up on the tissuePosted 3 years agonikkMember
Shimano brakes do this.
It is likely that the seals are gone and they are spraying a very fine mist of oil on the rotors / pads. You may need to pull them hard to make them do this.
Once the pads are contaminated with the oil, you can’t clean them. When I had them, I tried everything – sandpaper, scrubbing with soap, meths, brake cleaner, isopropyl, baking in the oven, setting them on fire. None of that worked.
So basically, you need a new braking system, as apparently you can’t get new seals for Shimano.
Do yourself a favor and get some Hopes, and get them properly set up. Shimano are good out the box, but once they go, they trash everything and can’t be fixed, put me off for life.Posted 3 years agojambalayaSubscriber
The mystery of screeching brakes, over the years I’ve found it just tends to come and go as such Inalways out it down to impurities on the rotors casuing the pads to slip / stutter on the rotors as it seemed to come and go and get worse as day went on. Stopping it seems to be a dark art.Posted 3 years agoFat-boy-fatSubscriber
If it is the next to latest version of the xts, they’re pretty legendary for the seals letting go. I had three brakes let go. Grr. I replaced them about 18 months ago with the new xts (the ones with the silver barrel as the reservoir on the levers). They’ve been perfect. No worries about the Hayes rotors. As long as they’re within 5 mm of the Shimano ones, no worries. Ran Tektra rotors for years on Shimano brakes when they insisted on centre lock. No problems.Posted 3 years agocoreMember
I’ve got new deore’s on my bike, from the £65 PSA a few months back. Front one just won’t stop squealing for any length of time, have bled and re-bled (with block), cleaned rotor several times & sanded (organic) pads more than once.
Last weekend they were unbelievably loud to start off, regardless of how hard I was braking, then, on a long, downhill road section I did several hard stops & got some fair heat into them, they were then fine until the end of the ride, almost silent. Went to the bike today, squealing again, even if pad only just touching rotor.Posted 3 years ago
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