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Squeaking disc brakes - but not when braking!

beelzebombbeelzebomb Posts: 94
edited June 2014 in MTB workshop & tech
I'm a bit stumped on this one as my Avid Juicy discs, front and rear, started squeaking as I ride along during last/this winter, I've removed and cleaned the brake pads, sanded them, and cleaned the disc rotors but still they squeak, but not as bad as before and it possibly gets better when they warm a little.

Braking isn't the problem, no noise at all there, just when I ride along which is as annoying as it is embarrassing!

Clearly they are touching the discs very slightly for this to happen - lightly feathering the brakes stops it - any ideas anyone?

Posts

  • kajjalkajjal Posts: 3,380
    It sounds like the calliper is slightly misaligned causing a small amount of rub. Slightly loosen the calliper bolts , pull on the brake, while keeping the brake on tighten the calliper bolts and then release the brake. If you spin the wheel it should be fine now. If not you may have uneven rotors or the calliper has an uneven action so you will need to adjust it by eye.
  • fielonatorfielonator Posts: 100
    If they're hydraulic then they may need bleeding. I had a similar problem with my elixrs. It seemed they weren't retracting fully, or at least one side wasn't, and the drag was causing the squeeling.

    I agree it's very annoying. Especially on the way up!
  • cooldadcooldad Posts: 32,601
    No. No no no.
    Bleeding is for removing air from the system, not curing random noises.
    Just no.
    I don't do smileys.

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  • fielonatorfielonator Posts: 100
    That's right. Air in your system can prevent the calipers from retracting properly as they rely on both positive and negative pressure in order to move. Unless there are return springs, which there aren't.
  • cooldadcooldad Posts: 32,601
    OP says brakes work fine - air causes them to be squidgy.
    Random bleeding causes a lot more problems than it solves.
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

    London Calling on Facebook

    Parktools
  • If your bike or pads are new there just bedding in?
    DVN
  • The RookieThe Rookie Posts: 27,748
    Callipers aligned correctly, and if they are, are the pads worn of alignment?

    DO NOT BLEED them hoping to fix this!
  • fielonatorfielonator Posts: 100
    There's nothing wrong with giving your brakes a random bleed now and then. And it does work, at least it has for me.

    There's nothing to be afraid of. As long as you know what to do and clean up afterwards you won't cause any problems. You may cure one though. It's a bit like curing the hiccups sometimes. You don't need to know why it works, only that it did.
  • cooldadcooldad Posts: 32,601
    I'm glad you're not a doctor.
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

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  • fielonatorfielonator Posts: 100
    Actually I am a doctor. As such I am adequately qualified to say that when my brakes are a bit squeely I bleed them.

    Before you ask, sorry but I won't have a look at your foot/elbow/other poorly bits.
  • cooldadcooldad Posts: 32,601
    cooldad wrote:
    I'm glad you're not a real doctor.
    FTFM
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

    London Calling on Facebook

    Parktools
  • WindyGWindyG Posts: 1,099
    fielonator wrote:
    Actually I am a doctor. As such I am adequately qualified to say that when my brakes are a bit squeely I bleed them.

    Just adequately qualified, I think we can all be adequate at many things rather than very well qualified and actually good at them.
  • fielonatorfielonator Posts: 100
    Read it again windyg
  • Chunkers1980Chunkers1980 Posts: 8,035
    Reading it again says to me that you are recommending a random bleed to stop squeaking. Less than adequate strikes me.
  • cooldadcooldad Posts: 32,601
    The Rookie wrote:
    cooldad wrote:
    I'm glad you're not a doctor.
    Indeed, fancy a nice random appendectomy or two!
    I believe that's a random cure for both impotence and ingrown toenails.
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

    London Calling on Facebook

    Parktools
  • fielonatorfielonator Posts: 100
    fielonator wrote:
    when my brakes are a bit squeely I bleed them.

    I'm not really a doctor, haven't got the patients.
  • beelzebombbeelzebomb Posts: 94
    Ok, thought I'd report back: bleeding holds no issues for me as I put together the bike from the frame up, so not bothered by the hassle of it all if it wasn't the issue.

    So I bled them (shortening the annoyingly long cables at the same time) & noticed no difference. I turns out the tolerances are so small that the slighted misalignment causes this - so loosening the calliper bolts and squeezing the rake tight then tightening sorts the problem. Bit annoying though, as potential is I have to do this each time I remove a wheel!
    Shame there's not a wind in/out allen key bolt on the calliper itself. Thanks for all the advice, as always it turns out to be the simplest thing in the end, but at least I have shorter brake cables now!
  • WindyGWindyG Posts: 1,099
    It was always going to be that easy, bleeding them just get's banged around way too easy as a solution.
  • kirby700kirby700 Posts: 458
    beelzebomb wrote:
    I turns out the tolerances are so small that the slighted misalignment causes this - so loosening the calliper bolts and squeezing the rake tight then tightening sorts the problem. Bit annoying though, as potential is I have to do this each time I remove a wheel!
    Shame there's not a wind in/out allen key bolt on the calliper itself. Thanks for all the advice, as always it turns out to be the simplest thing in the end, but at least I have shorter brake cables now!

    Having to adjust the brakes like that hardly a hardship like that though. How often do you need to remove the wheel anyhow?
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  • beelzebombbeelzebomb Posts: 94
    No it's not a hardship but it's an inconvenience.
  • photonic69photonic69 Posts: 1,077
    I had a similar issue with my brakes. Had to adjust caliper each time I put front wheel on. This happened a lot due to transporting bike in the car. Turns out it was a very slightly bent axel. Not enough to cause an issue apart from the brake rubbing. I scratched a groove into one of the flats of the bearing cone locknuts. Al long as that Mark is lined up with the fork dropouts then the brakes don't rub.

    Worth a try?
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