Front brake stuck in crown

Gary_T
Gary_T Posts: 52
edited June 2012 in Workshop
As above, I'm having no luck taking the dual pivot front brake unit from my Specialized Allez, it seems to be well and truly stuck even after a good soaking of wd40 (I have removed the nut at the rear of the crown, honest).
I'm reluctant to get too heavy handed with it in case I damage the forks etc.
Any tips would be much appreciated...

Comments

  • sungod
    sungod Posts: 16,559
    wd40's reputation far exceeds its efficacy

    if you've got the nut off but can't get the brakes out then perhaps there's been some corrosion, you could try plusgas or acf50

    maybe you can remove it without...

    with the wheel out, holding the fork with one hand, get a grip on the brake and try wiggling it up/down/left/right, you might be able to loosen it that way

    brace the front of the forks with a bit of wood, put the nut on a few turns so that the threads are protected, then give some taps on the end, use something hard but light so that the impact is sharp but without a huge mass following through

    when refitting, put some antiseize on it
    my bike - faster than god's and twice as shiny
  • Gary_T
    Gary_T Posts: 52
    cheers for that, i'll give it a go.
    there is evidence of corrosion, i guess all the months of riding it in the wet have cost me dear
  • redvee
    redvee Posts: 11,922
    Try rotating the calliper after removing the cable. The rear calliper on my Allez had to be rotated as the hole was very tight on the calliper.
    I've added a signature to prove it is still possible.
  • Yossie
    Yossie Posts: 2,600
    Yup - I had the same problem when changing teh front Ultegra for a 105:

    Take the cable out, the nut off the back, grab the brake and use that to turn itself out. It'll be well tight at fist but then come oose when your are least expecting it, causing it to spin round faster than Joe Hart's head when Pirlo chipped in his penalty last night and for you to smack you knuckles on the frame and forks.

    I suggest that you then smash the whole bike with a hammer, throw it into next door's garden then buy a Ritte wih full Red 2012/2013.

    If you insist on re-fitting another brake, then loads of copperslip everywhere.
  • g00se
    g00se Posts: 2,221
    What's the fork material? If it's alu and that part of the calliper is steel - then it could be galvanic corrosion. If that's the case. plusgas and WD40 won't help. To break down the corrosion, use ammonia or even a can of coke (seriously).
  • Gary_T
    Gary_T Posts: 52
    some interesting ideas there, might have a go at the coke 'n' twist method. if it doesn't work i can always stick some jd in the left overs and drown my sorrows.
    not sure what the crown is made of, i suspect alu, there was a lot of white bubbly, powdery crud around the nut (which was also a bugger to get off).
  • g00se
    g00se Posts: 2,221
    The white powder is aluminium oxide - aluminium doesn't corrode badly with water, as aluminium oxide is waterproof -so as soon as there's a thin film of oxide, water can't penetrate any further. The bare metal just looks a dull grey. However, if the water is acidic (such as dissolved road salt in winter), then it can penetrate, and the acid eats under paint surfaces to make powdery, white corrosion.

    Try the coke, it might help. However, just to check, is it a carbon fork with an aluminium crown? If so, make sure the corrosion isn't around where the crown bonds to the carbon arms, as that could be dangerous.

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