Disc Brake Wont Stop Rubbing

stevet1992
stevet1992 Posts: 1,502
edited October 2008 in MTB workshop & tech
Ever since i bought my carrera vulcan disk from halfords a few weeks ago the back disk brake rubs. After adjusting the brakes this still didnt stop the rub so i took it down to halfords. The guy there looked at it and said that it was bent so procedded to fix it and it stopped rubbing.

Now the problem has come back and im at my wits end what to do about it :( What do you guys reckon will fix it?

Was hoping to go out on a ride up at chilham tomorrow but this and the bad weather means im not :x

cheers in advance :D
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Comments

  • nicklouse
    nicklouse Posts: 50,675
    well they have not fixed it yet so take it back.

    Or read the info on park tools about setting up whatever brakes you have.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • TomJG
    TomJG Posts: 9
    Interesting...... I bought the same model off a mate a few months back. A couple of days ago the same thing happened: the rear brake rubbing once every revolution. Adjusted the pads, had the wheel off, cleaned everything out...ended up worse than when I started. Now the static pad is rubbing continuously against the rotor with no more room for adjustment.

    Was it the rotor or wheel which the Halfords chap fiddled with??

    T
  • stevet1992
    stevet1992 Posts: 1,502
    he was fiddling around with the rotor

    i figured out that as the disc brakes have one static and one moving pad the rotor gets slightly bent under the pressure of braking

    well thats what i think it is :lol:
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    Calling All SouthEastern Riders
  • johnsav
    johnsav Posts: 775
    no, that would be fairly stupid!

    Caliper probably needs centering
  • TomJG
    TomJG Posts: 9
    "no, that would be fairly stupid!"

    Why is that a stupid assumption? If the static pad is set too far away from the rotor then the pad which moves will be forcing the rotor significantly out of true....Do this enough and its going to show. Would explain why my system has gradually been getting worse and why the rear brake is worse than the front (through harder braking).

    t
  • nicklouse
    nicklouse Posts: 50,675
    TomJG
    correct so the static piston needs moving towards the rotor.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • andrewjoseph
    andrewjoseph Posts: 2,165
    if it is rubbing continuously then the rotor is likely bent or the piston not retracting, if it is rubbing in one spot then the rotor is warped.

    Not sure of the brakes but if they sound like the hayes sole. once you have straightened out your rotor (which may well warp again after heating), you can adjust the static pad so it is closer to the rotor. this means less rotor 'skvish', better lever feel and better braking.
    --
    Burls Ti Tourer for Tarmac, Saracen aluminium full suss for trails
  • TomJG
    TomJG Posts: 9
    Unfortunately its got the stage where the static pad is adjusted as far away as possible from the rotor and is still rubbing almost continuously. Think I may have bent it cycling back from Morrison's with a heavy rucksack full of shopping (HARDCORE!).

    Read a couple of articles which suggest taking bends out using an adjustable spanner to physically bend it back... Is this possible/wise on a such a knackered rotor?

    Cheers for the info chaps/chapettes.... been riding for a while but never had to deal with this before. Nice forum!

    t
  • andrewjoseph
    andrewjoseph Posts: 2,165
    I 'tweak' all the rotors on the family bikes regularly to keep them as straight as possible, though none are as bad as you mention.

    If they keep warping it maybe due to poor materials. you can buy rotors quite cheaply though.
    --
    Burls Ti Tourer for Tarmac, Saracen aluminium full suss for trails
  • stevet1992
    stevet1992 Posts: 1,502
    sorry about the late replys guys

    will have a look tommorow at my calipers see if i can move them closer but as far as i can remember there is only one little allen key adjusting bit

    shall post back tomorrow as its to freaking cold to go outside right now :lol:
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  • bonyjoe
    bonyjoe Posts: 48
    If it squeaks horribly when you move the bike back and forth very slowly then the caliper has been knocked of alignment slightly and the disk is catching on the caliper. This was happening with mine and it was fixed by simply loosening the caliper and adjusting it slightly.
  • andrewjoseph
    andrewjoseph Posts: 2,165
    more info on brake problems here:

    http://www.ba-joseph.co.uk/brakes/brakes.html
    --
    Burls Ti Tourer for Tarmac, Saracen aluminium full suss for trails
  • stevet1992
    stevet1992 Posts: 1,502
    ok guys its got worse :(

    now the back ones gone and makes a grinding like noise(part way between rubbing and grinding)

    any ideas?
    On-One 456 Sainsburys Season

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  • stevet1992
    stevet1992 Posts: 1,502
    all sorted now

    all i had to do was take the caliper off and place it back on :shock:

    sometimes the hardest questions have the easiest solutions 8) :lol:
    On-One 456 Sainsburys Season

    Calling All SouthEastern Riders
  • johnsav
    johnsav Posts: 775
    johnsav wrote:
    no, that would be fairly stupid!

    Caliper probably needs centering

    !! :lol:

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