XT brakes squealing, cause and cure?

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  • XT brakes squealing, cause and cure?
  • rideforlife2
    Member

    Sounds like contaminated pads/rotors (no pun intended), try Muc-Off disc brake cleaner works a treat.

    Although it could be that you did not bed in the pads in originally which means that there is a glaze over the pads causing the noise. Try riding up and down a road fast and then break hard. Repeat until noise stops but if it doesn’t then its time to buy Muc-Off or new pads/rotors.

    Hope it helps 😀

    Premier Icon luket
    Subscriber

    Reasonable chance of a bit of pad/rotor contamination in the time left in the shed. I’d clean the rotors and either sand/grind or replace the pads.

    Premier Icon Johnny Panic
    Subscriber

    You need to replace your rotors.
    I’ll have the old ones off you for a small commission…

    Premier Icon iain1775
    Subscriber

    No Steve you won’t 😉

    I thought contaminated pads too, but couldn’t figure out how when they have been tucked away out of the way of anything likely to contaminate them
    I’ll try a sand of the pads first, doubt they are glazed, after 2 hours riding and some serious braking to try and rid them of the noise they where still squealing
    I presume muc off brake cleaner is basically just isopropyl alcohol?

    monkeyninja
    Member

    This happened to my brakes as well, i have xt brakes and ice tech rotors. My bike sat in the spare room for 6 months without getting used (shoulder injury), and on the 1st ride out the noise was deafening and the brakes were rubbish, even though they worked fine before sitting for 6 months. No way they could have been contaminated. I sanded them and then hit them with the blowtorch and cleaned the rotors and they were back to normal, however, i let the bike sit for another month and the next time out squealing again, but all it took this time was some water from a bottle and they were quiet again, I think its dust from the air that gets on the pads when the bike is sitting and unless it washed off they squeal.. i could be wrong but they are fixed now.

    Premier Icon iain1775
    Subscriber

    Dug an old bike out last night that I had been considering selling and took it for a ride
    Fell in love with it again but there was an almighty squealing from the brakes (Latest Shimano XT)
    The brakes are quite new, think I fitted them, rode the bike twice then hung it up for the last 12 months but I’ve never known squealing like it, ear splitting and relentless

    What’s the likely issue and what’s the fix please?

    Bike has been suspended by the seat from the rafters in the garage, not left upside down/ upright or in any odd position, if that makes any difference

    Rotors are Shimano icetech

    nikk
    Member

    Shimano brakes spontaneously start squirting a fine mist of the brake oil onto the pads. This may happen on first pull of the levers. Cleaning may clear the problem temporarily, but it will come back. Pads contaminated with shimano oil are hard / impossible to clean. You need to change the calipers to fix the system, or do yourself a favor and get brakes that don’t have this problem. Hope are good.

    Premier Icon scotroutes
    Subscriber

    Nik wrote:

    Shimano brakes spontaneously start squirting a fine mist of the brake oil onto the pads.

    This is technically called twaddle.

    martinxyz
    Member

    Old slx do it. Heaps of brand new (and old) lower end calipers do it too. If the brake is left for a while it can often spit the dummy and appear to have a bit more dust on it than usual. It’s often noticeable as a mist over the caliper and not usually a wet look to it. Shimano have mentioned that the seals on some calipers can go a bit firm in colder temperatures.. letting the fluid seep. Funnily enough, late this afternoon I’ve just had a new xt (around 4 months old) dropped off that’s doing this.

    Edit: and a pair of 6 week old 446’s do it at each end of another bike yesterday afternoon. As great as their brakes are, they need to get these seeping issues sorted as it’s been an ongoing problem for quite some time now and it’s something no amount of ‘sealant’ seems to be fixing between the caliper halves. Come on,Shimano. It’s a shame as they are still great brakes throughout the range and I still use them as the hassle free side of every other aspect of their brakes outweighs all the chit you can get from brakes from other brands.

    nosedive
    Member

    Had this with some deore. Changed pads and rotors but it still came back so has to be something caliper related

    jaffejoffer
    Member

    ive got a set of Zee brakes on my fatbike that squeal like mad. when i crashed and snapped a brake lever on my covert i nicked the zee for a few rides and amazingly, no squeal!? back on the fatbike and they’re screaming away again.
    tried all sorts of magic potions and chemicals on my rotors but no joy??

    perthmtb
    Member

    There’s a long thread on MTBR about this.

    Nobody seems to have solved the mystery yet, but the most likely explanation is some kind of oxidation of the pads while sitting idle. Anyway, solution seems to be burn ’em in like you do when new, or just hit some wet gritty trails and let them sort themselves out…

    nikk
    Member

    ScotRoutes wrote:

    nikk » Shimano brakes spontaneously start squirting a fine mist of the brake oil onto the pads.

    This is technically called twaddle.

    I think that comment is quite unbecoming of you, Colin. I am surprised.

    I am talking from experience – I have seen this with my own eyes. And it sounds like others have as well:

    Hamish Martin wrote:

    Old slx do it. Heaps of brand new (and old) lower end calipers do it too. If the brake is left for a while it can often spit the dummy and appear to have a bit more dust on it than usual. It’s often noticeable as a mist over the caliper and not usually a wet look to it. Shimano have mentioned that the seals on some calipers can go a bit firm in colder temperatures.. letting the fluid seep. Funnily enough, late this afternoon I’ve just had a new xt (around 4 months old) dropped off that’s doing this.

    nosedive wrote:

    Had this with some deore. Changed pads and rotors but it still came back so has to be something caliper related

    Premier Icon Yak
    Subscriber

    I agree with the seal issue, oil spray thing. Had this on old slx and old deore. Cleaned rotors, discs, changed pads, then it happened again. If left for a while the calipers also look dusty.

    bigyinn
    Member

    Yep, take them for a nice muddy ride and then some nice hard stops to get them really hot. Sorts most pad / disc related issues for me.

    Premier Icon angeldust
    Subscriber

    This is technically called twaddle.

    🙄

    I’ve had some ~3 year old XT brakes do the same, and seen a few others. Ignore the naysayers above, the seals seem to degrade if the bike isn’t used for an extended period, causing brake fluid to contaminate the discs, causing the squealing. You can decontaminate the rotors/pads, but they will just be contaminated again next ride. As above, solution is new calipers (making sure the rotors/pads are fully decontaminated), or new brakes. Shimano are so cheap now I accept this limitation.

    akeys001
    Member

    had this, in my case (i don’t know the technical terms) but the silver metal thing where the cable goes into the caliper had oil in it (i.e. it wasn’t sealed properly) and the oil somehow got on the pads – replaced the cable and pads (I had tried muc-off/scratching etc and it didn’t do enough) and work fine now (having subsequently left it for another few months), hth’s

    ah, it was this…

    http://forums.mtbr.com/brake-time/xt-xtr-br-m785-warranty-brake-leaking-issue-785547.html

    retro83
    Member

    nosedive – Member

    Had this with some deore. Changed pads and rotors but it still came back so has to be something caliper related

    I had the same thing as angeldust above. New caliper = problem solved.

    It must have been a tiny amount leaking as the level in the lever never seemed to go down.

    Not twaddle. Well, I have no idea for the reason but have had the same happen with my 2015 XTs too.

    I broke an elbow and knee so my bike was stored for 8-10 weeks. The first time I rode, they squealed like buggery.

    A spray of Muc Off disc cleaner cured the rear but not the front. I replaced the front pads (they needed doing anyway) and that cured the front.

    Since then (3 months or so), nice, quite and powerful.

    Premier Icon iain1775
    Subscriber

    do yourself a favor and get brakes that don’t have this problem. Hope are good.

    I have Hopes on the other bike
    they are sh*t, need constant attention

    take them for a nice muddy ride

    easier said than done at the moment!

    Premier Icon DezB
    Subscriber

    If it was mineral oil, surely rather than squeal they’d lose all braking ability?

    nikk
    Member

    DezB wrote:

    If it was mineral oil, surely rather than squeal they’d lose all braking ability?

    No, they do both. The quantity of oil deposited is not enough to totally kill the braking.

    iain1775 wrote:

    I have Hopes on the other bike
    they are sh*t, need constant attention

    Not my experience at all. What is wrong with them? How old are they? Perhaps they need serviced?

    perthmtb
    Member

    take them for a nice muddy ride

    easier said than done at the moment!

    Backup option is take them for a dry and dusty ride and regularly douse them in water from your water bottle 😀

    deviant
    Member

    Had some new Deore 615s behaving less than impressively. Took the rotors off and scrubbed them with detergent to get rid of any potential oil, ordered new pads from Uberbike and then very carefully reinstalled everything making sure to avoid contaminating any part of the braking surfaces.

    Result is awesomely powerful brakes with no fade or noise. Try it.

    soobalias
    Member

    some of the above is interesting, would be useful if people could state which pad material and maybe where the pads were from.

    my zees have sat unused for a couple of months and have a horrendous squeal just moving the bike in the shed. feeling that the pads are semi metallic (stock) however, so getting rid of them is my first solution.

    deviant
    Member

    My pads are by Uberbike in their Race Matrix compound.
    First ride was underwhelming, they required most of the ride to bed in, after that they’ve been fine….to the point that next time I took the bike out I braked as I had on the previous ride and nearly pinged myself over the bars.

    The bike gets a hard time and in the last month has been to BPW, FoD, Rogate DH and some local XC routes. No signs of fade or wear yet, completely silent and only ever requires one finger braking.

    The rotors are Avid 180mm F&R, seriously making me question the wisdom of fitting the Zees I have under the stairs to my full-suss when I build it back up….might just sell them, buy Deore again and pocket £100.

    Can the seals ‘un-shrink’ once the brakes are in use again? In the three months since swapping pads / cleaning, I haven’t had any issues.

    Maybe the tiny amount of fluid that made it squeal when they sat un-used just disappears when the brakes are in use.

    I had the OEM finned ones (semi-metallic) and now have Shimano, unfinned metalic.

    In the past couple of years, I’ve run HOPE X2, M4 and these XTs. 203mm front and either 160 or 180mm rear. Even if they were the same price, I’d take the XT over the others. I keep trying to justify a Zee front caliper but can’t.

    The XT are on a heavy 180mm travel FS, are used heavily and besides the (fixed) squeal, are yet to perform anything other than ‘fantastically’.

    Premier Icon iain1775
    Subscriber

    Pads ‘cooked’
    Discs and pads cleaned and scrubbed with isopropyl alcohol, and given a sand down
    Will see how they go tomorrow
    Email sent to Madison as well to see their thoughts on warranty
    Thanks everyone was totally unaware of the leaking issues until I started this thread

    Nikk- yes the Hopes need a rebuild and I am going to send them off as it’s easier than me, finding time to do them but at at least £45 an end it’s almost cheaper to buy new Shimano’s (which I would be doing if the Hopes where not green V2’s and I wasn’t a bit of a tart!)

    martinxyz
    Member

    Makecoldplay.. it seems so. On my own bike that I have the leaking slx on, I have clarted it with a bit of mud and it’s had pretty good power each ride although not full on power that it should have. It’s a mi ncing fire track/easy trails bike and it’s never bothered me. The last time I dragged it out of the cold shed, the lever travel and bite point was way down and yet again, the brake was howling. I think it’s really died this time. I think it was fine for the first few years and then this came on gradually (maybe 4 years old now) over the winters. The dust sticking to the caliper like someone mentioned above is a common sight on many calipers. Heaps of cheaper ones on brand new bikes, my first gen slx, both my bosses xtr calipers and a few xt’s.

    edit: Yet still my fav brake brand!

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