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Clicking disc brakes!

(13 posts)
  • Started 11 years ago by remberbuck
  • Latest reply from Baldcyclist
  • This topic is resolved

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  1. remberbuck
    Member

    I thought mechanical disc brakes were made to be simple maintenance - cables and pads and that was about it. Descending South Lauder I found my rear brake not working - not a real problem, probably just needing some cable tightening.

    So, that was done, all working well on the stand, set off the next day, but then found that as soon as I applied some pressure, something seemed to give, and instead of the brake coming on, all that happened was a clicking noise as the pads tried to apply themselves.

    Weirdly, when I loosen off the cable tension, and then retighten I get the same, i.e. the brake works fine until serious pressure is tried. I have tried various tension levels, recentered the pads, and remounted the brake on the frame, all the usual suspects. I've not explored the shifters yet, but the problem doesn't feel like it comes from there.

    Ideas?

    The brakes are Tektro Lyra and the shifters are Tiagra.

    Posted 11 years ago #

  2. Arellcat
    Moderator

    If it isn't the cable or the brake lever, it must be the caliper. There may be a failure in the helical groove and pin of the actuating lever.

    Posted 11 years ago #

  3. DaveC
    Member

    Hi Remberbuck,

    I have this problem. The solution is to take a long allen key and bring the inner pad to the disk. What happens as the pads wear is the disc starts to bend under braking. Only the outer pad moves so as pads wear the outer pad comes in and pushes the disc over to the inner pad. The inner pad needs to be brought into as close to the disc as possible without locking the wheel.

    The brake works by moving the brake arm (attached to the cable) up a 'ramp'. As the arm moves up the ramp (think sideways), it pushes the pad in. At the limit of the ramp the arm/pad reaches the top of the ramp, and 'falls off the end'. Think door stop wedge, going up the shallow side and falling off the end.

    The solution is to keep your eye on the braking, by monitoring the movement/reach of the brake lever and adjusting the inner pad in. Stop the wheel, poke a long allen key in through the cassette largest ring and spokes and trn the allen grub screw a few 10's of degrees and look down the line of the bike from the rear to monitor the inner pad as it comes in.

    I bought these from Aldi: Work Zone Hex Key set

    Hope this helps.

    Dave C

    Posted 11 years ago #

  4. Baldcyclist
    Member

    Another annoying issue I find with disc brakes (I have Avid BB5/7) is that the spring is on the pad side of the pad, which lessens the service life off the pad for no apparent reason. Some of the springs even have a wee protruding bit which lessens life even more - I bend it straight with pliers - which if not bent back then catches on the disc giving a clicking noise.

    I love the stopping power of disc brakes, but they are a complete faff, to get just, so...

    Posted 11 years ago #

  5. 14Westfield
    Member

    My main bugbear with cable discs is that they only move on one side and create the problem you've got here. Having to keep dialing in and balancing the pads removes any 'low maintenance' benefits.
    You might want to keep an eye out on eBay/sales etc for hydraulic brakes as its a pretty easy replacement of calipers snd levers and you'll get a far, far better result.

    Posted 11 years ago #

  6. Baldcyclist
    Member

    "
    You might want to keep an eye out on eBay/sales etc for hydraulic brakes as its a pretty easy replacement of calipers snd levers and you'll get a far, far better result.
    "

    Would hydraulic work on a road bike (tiagra shifters)?

    Posted 11 years ago #

  7. DaveC
    Member

    Remberbuck, I have the same Tektro Lyra's you have, and this is how I solved the same problem you have now, in the past.

    Posted 11 years ago #

  8. LaidBack
    Member

    All the above valid but do check your disc rotor is on tightly. Unbelievably I had a new centre lock one work loose. Thought it was pad but in fact rotor (disc) was moving. Rare occurence.
    If you are six bolt then less likely.
    Even with this loose it still stopped ok but made noise which were pads and rotor touching.

    Posted 11 years ago #

  9. remberbuck
    Member

    Many thanks for all the advice. I am particularly grateful for DaveC' s thoughts and experience. Tightening the wheel side screw as suggested makes such obvious sense, and, I have to admit, much cleaner than fiddling with side pulls.

    Still to be put to the test. Wish me well down the Mound to get the Glasgow train tomorrow!!

    Posted 11 years ago #

  10. Dave
    Member

    Hydraulic is all very well until one piston siezes or you get a leaky seal. Then not only is it hard to fix but you have highly nasty brake fluid all over you and everything else.

    2/3 of our disc bikes are hydraulic but I don't love them.

    Posted 11 years ago #

  11. kenny
    Member

    I had the same brakes on my Revolution Country Explorer, and I fortunately first experienced this "click of doom" coming to a stop at a relatively safe junction - would have scared me silly if it was on a downhill!

    I spent a couple of weeks trying to adjust the failing front brake to be safe. The Interweb is sprinkled with similar reports, and in the end I replaced both of them with BB7s.

    I handed the old ones into the Bike Station with a verbal and written warning about their behaviour.

    Posted 11 years ago #

  12. DaveC
    Member

    My rear Lyra is not working very well. I've changed pads, cables (inner and outer), and rotors. Next option is to service the caliper but I'l seriously looking at BB5s.

    I think I'd have to get a pair as I don't want to have to be buynig two sets of different pads.

    They are nice brakes - for disc brakes but if I can't get them working, by taking apart then they're destined for the Bike Station/bin.

    Dave C

    Posted 11 years ago #

  13. Baldcyclist
    Member

    but I'l seriously looking at BB5s.

    I'd go for the BB7s (I have BB5 rear, BB7 front). Can't service BB5s beyond pads, and you can't easily move the outer pad in. My BB5 seized after 1 winter, and I have heard others on twitter with same issue.Bike shop managed to un-seize it bit told me once it goes again it's gone.

    At least if a BB7 seizes you can but all of the inners as spares so can fix. The pad surface area on the BB7 is also much greater than a BB5, but the spring in the BB5 is better (doesn't foul on the disc).

    When my rear BB5 gives up the ghost (probably this winter), I will replace with a BB7.

    Posted 11 years ago #

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