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Why did my brakes fail??!!

FerralsFerrals Posts: 785
edited January 2015 in MTB workshop & tech
About 25km into a wet and muddy xc ride my front brake(xt) suddenly stopped working thankfully just before I headed down a very muddy descent - it had been fine and then suddenly I could pull the lever to the handlebar with no slowing down. My first thought that the pads had run out but they still have a fair bit on them. Then I wondered in the calliper had got knocked but it seemed ok (I re centered it when I got home but it's made no difference).

So what has gone wrong!? And how do I prevent it happening in future? Can brakes suddenly need bleeding? I've tied the handle back to the bar overnight and will see if there's any air risen to the top. Any other reasons to check?
Getting back home with one brake was a wee bit sketchy!

Posts

  • nicklousenicklouse Posts: 50,675 Lives Here
    Sounds like failed seals.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
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  • FerralsFerrals Posts: 785
    Ah ok, can i replace the seals or is it a new caliper/ lever required? Anything in particular that causes them to go? Given the brakes are under a year old am I likely to get them under warrenty?

    Edit. And how do I tell if it is the seals - I reckon you are right though I I just went out to look and while I couldn't see anything, when you pull the lever it feels like they bite, but then if you pull a bit harder they give and can be pulled all the way to the bar, which to me makes sense with some kind of leaky seal.
  • The RookieThe Rookie Posts: 27,811
    What make and model?
    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.
  • FerralsFerrals Posts: 785
    Shimano xt, only 4-5 months old, so I figure will get warrenty if it is the seals. Only ever cleaned with alchohol spray as per instructions.
  • The RookieThe Rookie Posts: 27,811
    XT aren't serviceable, so whatever has failed needs to be replaced, yes should be able to get that fixed under warranty.
    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.
  • FerralsFerrals Posts: 785
    Ah cool, will swing by the shop later and see what they say
  • LittlebigmattLittlebigmatt Posts: 129
    Madison should replace it under warranty for you, just so you know though, they can take their time doing it. Unless your shop has another one in stock they should be swap it for you and then they'll take the new one.
    Cotic BFE MK II
  • FerralsFerrals Posts: 785
    Took it in today and it's the diaphragm that's gone. Will pop back tomorrow and see if there is a way they can just switch it for a new one as a) not having a bike is going to mess with my training and b) the wife is a off on a girls weekend next weekend so I was planning on a weekend of hard riding which sounds like it may have been scuppered :(
  • FerralsFerrals Posts: 785
    Littlebigmatt wrote:
    Madison should replace it under warranty for you, just so you know though, they can take their time doing it. Unless your shop has another one in stock they should be swap it for you and then they'll take the new one.

    Out of interest, by 'take their time' how long do you mean? Also it's the diaphragm that's gone - is that not a replaceable part? Trying to find out on the net but shimano so tech doc aren't loading for me.
  • The RookieThe Rookie Posts: 27,811
    Nope, not replaceable
    http://si.shimano.com/php/download.php? ... -3161C.pdf

    Techdocs website has changed URL
    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.
  • FerralsFerrals Posts: 785
    edited January 2015
    Cheers. going to phone madison this morning and ask for a estimated time

    edit: Had a result, Madison said it would be three weeks unless te bikeshop could request priority warrenty, so I phoned up to ask about that. Twenty minutes later got a phone call back saying - we are certain it will need replacing so we've fitted a new one already and will get the warrenty one in due course :D
  • *AJ**AJ* Posts: 1,080
    £20

    Gets you a brake for this weekend!

    Nothing flash, but at least you can get out on the bike! :)

    http://www.chainreactioncycles.com/shim ... prod119954
  • FerralsFerrals Posts: 785
    no need - see my edit above :-)

    credit where credits due, big stores get a bit of a knocking but this was Tredz that sorted it for me.
  • *AJ**AJ* Posts: 1,080
    Great news!
  • LittlebigmattLittlebigmatt Posts: 129
    Good that Tredz sorted you out quickly, I'm guessing you get what i mean by taking their time now with regards to Madison.
    Cotic BFE MK II
  • cooldadcooldad Posts: 32,599
    The warranty is with Tredz anyway. Madison are the distributor.
    I don't do smileys.

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