Juicy 3 Brakes now making a metallic scrape noise - help

Anonymous
Anonymous Posts: 79,667
edited February 2009 in MTB workshop & tech
Hey guys,, here is the problem with my front juicy 3 disc brake.

Every half revolution of my front wheel the front disc makes a kind of scrape noise, that sounds metallic to me and a little 'hollow'.

I've used disc brake cleaner on it heaps and that doesn't appear to work.

The brakes still brake fine but I am loosing a little confidence in the front wheel. Bike is only 8 months old, used it quite a lot on trails and a minor downhill.
brake also squeaks under heavy fron braking.

Any ideas on how to fix this? I've got the Hellfrauds service thingy but am hesitant to take it to them.

Thanks..

oh any links would help so I can fix myself.
Thanks

GmanUk101

Comments

  • dav1
    dav1 Posts: 1,298
    how worn are the pads?
    Giant TCR advanced 2 (Summer/race)
    Merlin single malt fixie (Commuter/winter/training)
    Trek superfly 7 (Summer XC)
    Giant Yukon singlespeed conversion (winter MTB/Ice/snow)

    Carrera virtuoso - RIP
  • Anonymous
    Anonymous Posts: 79,667
    Dav1 wrote:
    how worn are the pads?

    Dont think they are that worn much.. although i've used it 6 miles per day during week and approx 20 trail/dh miles everyother weekend since august.

    the back pads dont make a noise at all.

    Cheers

    G
  • Daz555
    Daz555 Posts: 3,976
    Are you saying that you are getting disc brake rub even when not applying the brake?

    If so then you probably don't have the caliper alligned properly or have a warped disc.

    Check my post half way down this thread: http://www.bikeradar.com/forums/viewtop ... t=12608034
    You only need two tools: WD40 and Duck Tape.
    If it doesn't move and should, use the WD40.
    If it shouldn't move and does, use the tape.
  • .blitz
    .blitz Posts: 6,197
    GmanUK101 wrote:
    Every half revolution of my front wheel the front disc makes a kind of scrape noise, that sounds metallic to me and a little 'hollow'.

    brake also squeaks under heavy fron braking.
    They sound (haha) just like mine. It seems everytime I go out they make a different noise. When it was really cold, the back one used to 'hum' when I was freewheeling e.g. DH; now it's warmer the back one has gone quiet but the front one squeals under moderate - not light or hard - braking :roll:

    Generally speaking, disc brake squeal is related to the stick-slip action of the pads on the discs - like a bow on a violin - and can be cured by applying a little copaslip or silicon compound on the back of the pads. I think a lot of the problems with discs on MTBs are related to the very tight tolerances required to maintain a decent 'bite' while at the same time making sure the pads retract fully from the discs. The pistons need to be very clean to keep them sweet.

    I remember when all we had were cantis, and that was if we were lucky...
  • Anonymous
    Anonymous Posts: 79,667
    Daz555 wrote:
    Are you saying that you are getting disc brake rub even when not applying the brake?

    If so then you probably don't have the caliper alligned properly or have a warped disc.

    Check my post half way down this thread: http://www.bikeradar.com/forums/viewtop ... t=12608034

    Cheers mate, will give that a go. thanks for the advice.

    G