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Sudden loss of brakes! (disk brakes)

J_asonRJ_asonR Posts: 55
edited October 2012 in MTB workshop & tech
Bonjourno,

So I was riding today with a mate through the New Forest, through mud and puddles that just covered anywhere we wanted to go! Anyway, about an hour into it and we were coming down a nice gradual slope back onto the main road in which we needed to follow for a while to get home..

About 30 metres from the road, and travelling at some speed I decided it was time to stop and used the brakes lightly to come to a slow stop.. Unfortunately, that wasn't the case and there was nothing coming from the brakes!

Not an ideal situation but I managed to avoid a car and hop my way onto the road to then slowly come to a stop..

I tried to tighten my brakes with the adjusters on the levers however only the front one made any difference but was still very slow to bring me to a stop..

Does anybody know what this could be? Unfortunately I'm not too savvy on the old mechanics of a disk break so it really could be something simple which I'm overlooking..

Thanks!

Posts

  • nicklousenicklouse Posts: 50,675 Lives Here
    and the brakes are ?

    got any pads left?
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • The RookieThe Rookie Posts: 27,804
    So is the lever coming back to the bar or is it firm and just not braking (breaking is what may happen when the brakes don't work).

    Hydraulic or cable?
    Current steed - Whyte T129, 2013 frame, mongrel Revelations, Giant dropper, Stans S1 wheelset. 12, Magura Trail Sport brakes, 1x11. 12.8Kg
  • J_asonRJ_asonR Posts: 55
    Cable Disks..

    The level comes all the way to the bar and there is the very very slightest amount of friction on the disks.. It's strange because it was only today that it's been like that, and I don't think it has been declining in efficiency, more a sudden drop!
  • The RookieThe Rookie Posts: 27,804
    Probably worn the pads down due to running in mud, the pad moves very little (its this mechanical advantage that makes them work, so you need to adjust them as stated in the manufacturers literature....most allow you to adjust both pads via a thumbwheel or allen key driven wheel, some you adjust via the cable tension.
    Current steed - Whyte T129, 2013 frame, mongrel Revelations, Giant dropper, Stans S1 wheelset. 12, Magura Trail Sport brakes, 1x11. 12.8Kg
  • nicklousenicklouse Posts: 50,675 Lives Here
    so any pads left?
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • J_asonRJ_asonR Posts: 55
    Probably worn the pads down due to running in mud, the pad moves very little (its this mechanical advantage that makes them work, so you need to adjust them as stated in the manufacturers literature....most allow you to adjust both pads via a thumbwheel or allen key driven wheel, some you adjust via the cable tension.

    Thanks for that, will have a little look and see what I can fiddle with..

    Nick, not sure at the moment.. I had a little look online and it says thats the main reason for this kind of thing, so I'm guessing theres minimal pad left
  • The RookieThe Rookie Posts: 27,804
    I would guess the pads will be fine, from nearly new the lever will come back to the bar long before the pads are worn out, in fact on my commuter I have adjusted the calipers 4 times and the pads still look barely worn.
    Current steed - Whyte T129, 2013 frame, mongrel Revelations, Giant dropper, Stans S1 wheelset. 12, Magura Trail Sport brakes, 1x11. 12.8Kg
  • J_asonRJ_asonR Posts: 55
    I would guess the pads will be fine, from nearly new the lever will come back to the bar long before the pads are worn out, in fact on my commuter I have adjusted the calipers 4 times and the pads still look barely worn.

    Google fails me for the first time! Okay, well I'll have a quick look on YouTube/Google as to how to go about it and give it a go tomorrow..

    Thanks again..
  • The RookieThe Rookie Posts: 27,804
    What callipers?
    Current steed - Whyte T129, 2013 frame, mongrel Revelations, Giant dropper, Stans S1 wheelset. 12, Magura Trail Sport brakes, 1x11. 12.8Kg
  • J_asonRJ_asonR Posts: 55
    What callipers?

    Sorry for the late response.. The callipers are TekTro IOX..

    I had a little look at what actually moves when the brakes are pulled and it seems that only one side of the pad moves, and it pushed the disc against the other pads to add extra friction.. I don't know if this is how it's supposed to be or whether both are supposed to grab each side of the disc like a V brake on the rim?

    Extra info would be greatly appreciated!
  • The RookieThe Rookie Posts: 27,804
    Only one side moves, you adjust the non moving side in until it is just off the disc (wind it in until it starts to rub then just back off a fraction) for best effect, also adjust the moving side in as well!
    Current steed - Whyte T129, 2013 frame, mongrel Revelations, Giant dropper, Stans S1 wheelset. 12, Magura Trail Sport brakes, 1x11. 12.8Kg
  • J_asonRJ_asonR Posts: 55
    Only one side moves, you adjust the non moving side in until it is just off the disc (wind it in until it starts to rub then just back off a fraction) for best effect, also adjust the moving side in as well!

    Thanks for that, do you know if it'll be a screw(or hex key) that sorts this on my type of calliper? Also where this screw might be located? :lol:
  • stubsstubs Posts: 5,001
    Tektro manuals about halfway down the page.

    http://www.tektro.com/_english/03_support/01_download.php
    Fig rolls: proof that god loves cyclists and that she wants us to do another lap
  • J_asonRJ_asonR Posts: 55
    stubs wrote:
    Tektro manuals about halfway down the page.

    http://www.tektro.com/_english/03_support/01_download.php

    So I'm looking for a big bolt! Haha, nah I know the one I need now! Thanks very much for that!
  • J_asonRJ_asonR Posts: 55
    So yesterday I manager to figure out the adjustments and got them all to as close to ideal as possible.. Unfortunately this doesnt seem to have made much of a difference.. I think i'm going to take te bike in and get them looked at or pads replaced at the lbs!

    Thanks for all your help though
  • The RookieThe Rookie Posts: 27,804
    Do the levers still come back to the bars? If so you've not adjusted it enough!
    Current steed - Whyte T129, 2013 frame, mongrel Revelations, Giant dropper, Stans S1 wheelset. 12, Magura Trail Sport brakes, 1x11. 12.8Kg
  • J_asonRJ_asonR Posts: 55
    The levers come back just over half way, I didnt what I was told by adjusting till it rubs then a little bit back.. When the pads are completely engaged on the disc it still hardly works.. Im guessing it must be the pads!
  • The RookieThe Rookie Posts: 27,804
    Possibly, but it's best to be really aggresive with your adjustment, also it's possible the pads just need to bed in again.
    Current steed - Whyte T129, 2013 frame, mongrel Revelations, Giant dropper, Stans S1 wheelset. 12, Magura Trail Sport brakes, 1x11. 12.8Kg
  • J_asonRJ_asonR Posts: 55
    Possibly, but it's best to be really aggresive with your adjustment, also it's possible the pads just need to bed in again.

    Thanks for your help.
  • J_asonRJ_asonR Posts: 55
    Got the bike into the LBS and for £10 they've sorted them!

    Don't know how they managed to do it, but having the right tools and knowing what to do probably helped a bit!
  • The RookieThe Rookie Posts: 27,804
    They either fitted new pads (doubt it for a tenner) ar adjusted it for which you should only need allen keys!
    Current steed - Whyte T129, 2013 frame, mongrel Revelations, Giant dropper, Stans S1 wheelset. 12, Magura Trail Sport brakes, 1x11. 12.8Kg
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