Tips for removing seized front brake fitment nut ?

andylav Posts: 308
edited October 2012 in Workshop
Went to remove forks from my good bike at the weekend and discovered that the recessed allen 'nut' holding the front brake on had become seized (discovered it was seized by rounding out the allen head slot).

Tried soaking pivot axle / bolt and nut in release oil and driving a bigger Tacx drive key into the rounded slot but this too rounded out.

Tried taking brake apart from the front to see if I could extract the entire axle, with nut still attached obviously, from the rear of the fork but that didn't work either (Zero Gravity brake, which I can't seem to dissemble completely - allen keys hurled across garage followed by pliers, screwdrivers and more than a few swear words).

Contemplating drilling the broader head of the retaining nut out / off (it's alloy rather than steel - hence why it seized in the first place - doh) as a last resort to extract brake from the front with remainder of the 'nut' sleeve still attached to the axle but worried about drilling too far and damaging the carbon mould of the fork against which the brake nut tightens.

Anyone got any other suggestions that I could attempt before I get the Black and Decker out ???


  • bikaholic
    bikaholic Posts: 350
    The way I would have done it would be like this:

    1. Remove the front brake pads to get clearance between the fork legs;
    2. Since the sleeve nut does not rotate, grab the whole caliper in one hand and unscrew it from the other side;
    3. Once the caliper is part way out, use a soft hammer to knock out the sleeve nut, or remove the caliper completely and screw in a matching threaded bolt and whack that to get the sleeve nut out.
  • andylav
    andylav Posts: 308
    Thanks bikaholic

    I had thought of trying this but the problem is that the sleeve nut is seized onto the brake pivot axle but not into the fork so the sleeve nut does turn within the fork with the brake caliper.

    Appreciate the suggestion though


    PS - I'm keen to retain future use of both the brake caliper and the fork so I've also ruled out cutting through the fork from underneath the crown to remove the brake downwards !
  • farrina
    farrina Posts: 360
    I used these bolt extractors ... yId_165572 to remove my rounded chainring bolt. Reviewers report varying degrees of success - reading around generally suggests that success rate can be as low as 50%

    Guess it depends on how stuck your recessed bolt is onto the brake axle and how deep a hole you have to introduce the extractor into before hitting the brake axle.

    Good luck!


  • andylav
    andylav Posts: 308
    Success !!!

    Tried a farrina recommended extractor - forgot I had some in the tool box - wasn't successful but the ensuing increased damage to the sleeve nut seemed to wedge it more firmly into the fork.

    Another good soaking of release oil and turning the brake, as per bikaholic's suggestion, resulted in the brake unscrewing from the front.

    Tapped the sleeve nut through, inspected the carbon with a torch and we're all good - what a relief !

    Thanks for your responses guys - much appreciated.