brake issue

chatlow
chatlow Posts: 845
edited May 2013 in Road beginners
Just replaced my Shimano tiagra front brake caliper due to what I thought was a fault. Even though I would tighten the main tube bolt at the back of the caliper to the fork, the brake would still rotate/move slightly when cycing over harsh road or pavement and the brake pad woud be up against the rim. Kept having to re-align the caliper. Anwyay, just got given a replacement shimano caliper and it's exactly the same!

How can I combat this? Would a washer help tighten the seal between the caliper and the fork?

thanks

Comments

  • smoggysteve
    smoggysteve Posts: 2,909
    I had a similar problem on my Via Nirone. I put a star washer on the bolt at the front of the fork, it had a flat washer before. The Allen key socket and bolt fastening is not the best and vibration can work it loose quite easily.
  • sungod
    sungod Posts: 16,544
    is the cable outer the correct length? if it's wrong it can push/pull the caliper off-centre
    my bike - faster than god's and twice as shiny
  • Haughjd
    Haughjd Posts: 93
    I'm having exactly the same.

    New bike 6weeks old. I start off on a ride then after about 10 miles the brake moves just enough to touch the rim. So I'm in effect peddling with the break on.

    should be due a service soon. I will ask the lbs to look into it.

    But I will be keeping an eye on this posting.

    As I want to understand more

    Jon
  • chatlow
    chatlow Posts: 845
    the cabling is fine (as far as i know)

    it's awkard to explain but when i tighten the main caliper bolt to the frame (and i mean super tight) it still isnt tight enough to stop the caliper from moving/rotating to the left or the right. i am able to rotate it to center the pads either side of the rim but as soon as i hit a pothole or rought bit of road, the caliper has moved and one of the pads is against the rim so im, as someone else pointer out, cycling with the brakes slightly on!

    i want it to be even tighter.. so that i center the caliper, tighten it into position and then it doesnt budge.

    im off to evans cycles next week to get my old caliper back so will ask them to fit it and take a look at the issue unless someone on here comes up with a potential cause before then :-)

    thanks
  • sungod
    sungod Posts: 16,544
    perhaps the mounting nut is just a bit too long and is bottoming out inside the fork? they come in different lengths, see if you can try a shorter one
    my bike - faster than god's and twice as shiny
  • smoggysteve
    smoggysteve Posts: 2,909
    I would suggest removing the whole thing and checking you have the correct washers and make sure nothing is wrong. If you have a carbon fork, which nearly everyone does these days, overtightening could eventually crack it. On mine it is the allan key socket at the back, on that is a flat washer. At the front, I have the bolt and a star washer in front of and behind the caliper another star washer.

    Remove it all and check for any damage and reassemble.
  • chatlow
    chatlow Posts: 845
    sungod wrote:
    perhaps the mounting nut is just a bit too long and is bottoming out inside the fork? they come in different lengths, see if you can try a shorter one

    thanks. yeah tried all three that came with the caliper and all seem to be ok
    I would suggest removing the whole thing and checking you have the correct washers and make sure nothing is wrong. If you have a carbon fork, which nearly everyone does these days, overtightening could eventually crack it. On mine it is the allan key socket at the back, on that is a flat washer. At the front, I have the bolt and a star washer in front of and behind the caliper another star washer.

    Remove it all and check for any damage and reassemble.

    unfortunately no carbon fork on mine! 2011 claud butler san remo. might be a washer issue. have tried with an without one which was same result but will look into different washers. thanks