Screeching XT brakes. Possible leak ?

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  • Screeching XT brakes. Possible leak ?
  • slackalice
    Member

    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?

    ashmonkey
    Member

    They looked clean but I swapped for new just in case. Didn’t try the sandpaper etc for that reason. I’ve only recently braved fettling with hydro brakes, do new pads always need bedding in ? I’ll give the sandpaper a try.

    slackalice
    Member

    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 afterwards

    Premier Icon phiiiiil
    Subscriber

    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…

    ashmonkey
    Member

    Might the caliper have a leak ?
    Lesson learnt about removing the pads. Its just I stuck new ones straight in, from an unused set of slx brakes. Within a few hundred yards they were the same, the disk had been cleaned as well as I could.

    ashmonkey
    Member

    Double post….

    ashmonkey
    Member

    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.
    I think it might be leaking on the caliper, is this common ? An easy fix ?

    Premier Icon bigjim
    Subscriber

    Mine have bizarrely started screaming recently too, haven’t put new pads in, its pretty embarrassing its so loud.

    My front one started it after the Keilder 2 years ago, still not sorted. Have just replaced pads, disc and bled it. If it’s not fixed now ibn getting a new caliper.

    ashmonkey
    Member

    Embarrassing indeed… I’ll give it one more thorough clean and sandpaper the pads then give up and get a new one… thanks for the replies.

    gonzy
    Member

    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 tissue

    ashmonkey
    Member

    No oil on the tissue, cleaned everything in sight and new pads and its exactly the same…… arse.
    One thing, could an obvious cause be using a hayes rotor with an xt caliper ?

    ashmonkey
    Member

    Bump

    Am I ok running Hayes rotors on xt calipers ?

    How are the wheel bearings? My front was squealing badly. Did all the usual things, then noticed play in wheel, New bearings no squeal.

    ashmonkey
    Member

    Bearings are good, bike only 8/9 months old, brakes a fair bit older though

    nikk
    Member

    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.

    ashmonkey
    Member

    Sat here thinking the same, probably just bite the bullet and replace them. Could it be the hayes rotor – xt caliper combo ?

    Premier Icon jambalaya
    Subscriber

    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.

    TurnerGuy
    Member

    regretting now deciding to try hydro brakes for the third time – just bought and fitting some XTs now 🙁

    Will keep the BB7s handy for when I want to put them back on…

    matther01
    Member

    My SLX were silent all the way around a dryish Dyfi last weekend…screeching like buggery this morning around a very wet and gritty Cannock.

    Sometimes its just down to the conditions and pad compound IMO.

    jag61
    Member

    Had exactly these symptoms on rear slx set last year they were by then about 18m old tried all the ‘cures’ no good pads were still getting contaminated replaced caliper all good so far. make sure all of the hoses/banjo bolts are compatible… it got a bit spendy 😳

    TurnerGuy
    Member

    I was thinking about the XTR brakes but saw a fair few complaints about loss of performance and several comments about the seals dying.

    Several of the comments included a period of non-use?

    ashmonkey
    Member

    Yep, the xt’s spent a year or so in the shed. Just fitting some slx ones I had for my soloist. The xt’s will retire back to the shed as an ornament. …

    All my other shimano brakes have been faultless with minimum care and attention.

    ashmonkey
    Member

    Slx working a treat, a happy boy at last.

    66deg
    Member

    The most effective way to clean pads i have found is using
    either disc cleaner or degreaser then scrubbing with a spark plug
    brush , it gets everything out of the tiny micro holes and stops the squealing .
    Hope this helps.

    TurnerGuy
    Member

    not a good start with my new brakes, no spare olives in the kit which seems rather stupid – how many bikes fit their cables exactly ?

    Premier Icon Fat-boy-fat
    Subscriber

    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.

    core
    Member

    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.

    fenred
    Member

    Ditto here too, just had rear 596 seals explode, 615’s on t’other bike seem ok ATM but seriously considering splashing out on some hope X2’s 😕

    rsl1
    Member

    remember shimano do a 2 year warranty (may have missed whether you say how old they are)

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