Howling rear brakes, nothing I do stops it!

badgerjockey
badgerjockey Posts: 36
edited September 2011 in MTB workshop & tech
Hey up all,

My rear Shimano M486 brakes (non-series but has been good in the past) just don't stop howling when even a modest amount of braking pressure is applied and it's driving me mental, let alone making me look like I'm hanging off the brakes on every corner (hehe, it matters!).

So far I have:

-bled them
-trued the rotor
-reset the brake caliper on the post mounts for perfect alignment
-changed the pads for new ones
-degreased and cleaned and dried the rotor
-detached and reattached the rotor off the hub...

So, what's left? Almost certain they're not contaminated pads. How about gunk in the piston seals etc? How do you clean or renew them and can you even buy new parts?

Any thoughts on the issue would be great.

H

Comments

  • nicklouse
    nicklouse Posts: 50,675
    what pads?

    and what did you use to clean the rotor etc?
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • badgerjockey
    badgerjockey Posts: 36
    I used muc off degreaser (can i use meths or should I buy the disc brake cleaner stuff?)

    and the pads are sintered, however the rotor says "resin pads only" on it - I just noticed!! Argh, I guess this is the culprit then....

    H
  • sheepshifter
    sheepshifter Posts: 115
    I have the same problem same brake screaming like a wild boar.Everything possible ive done new roter new shimano pads after binning numerous other brands but still the brake howls and lacks any sort of power.Somebody should know what next my lbs also are at a loss,this really is doing my head in i feel like binning them and buying a differant brand.Up till recently i felt these brakes were has good has my Avids and Hopes on my other bikes but at the mo a bag of s...e.
    PACE RC325.5 1x9

    GENESIS io SS
  • cooldad
    cooldad Posts: 32,599
    All Shimano discs say resin pads only. Makes no difference as the discs are made out of the same stuff everybody else uses.
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

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  • weeksy59
    weeksy59 Posts: 2,606
    buy Kevlar pads... they seem silent.
    Salsa Spearfish 29er
    http://superdukeforum.forumatic.com/index.php
  • captainfly
    captainfly Posts: 1,001
    hazzeryoda wrote:
    I used muc off degreaser (can i use meths or should I buy the disc brake cleaner stuff?)

    and the pads are sintered, however the rotor says "resin pads only" on it - I just noticed!! Argh, I guess this is the culprit then....

    H

    You should be using isopropyl alcohol (cheap on amazon) to clean brake most other degreasers (silicone is often used in these products) will contaminate the componenets. it can sometimes help to give the disks and pads a rub down with wet and dry paper then decontaminate, before properly bedding the set up.
    -_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_
    Mongoose Teocali
    Giant STP0

    Why are MTB economics; spend twice as much as you intended, but only half as much as you wish you could afford? :roll:
  • The Rookie
    The Rookie Posts: 27,812
    I use Alligator wind cutter discs, the 'chopping' noise drowns any whine/whistle very well!

    Make sure the adaptor is toqued up properly to the frame and than the QR is tight enough, whine's are a resonance and anything you can do to change the resonant frequancy away from what your hitting the better!

    Simon
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.

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