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Last year I got some SKS mudguards to fit to my cross bike for the winter. Stupidly when I was trying to fit the front one I managed to shear the bolt of the head off  20 Anyway I filed it down and managed to make the fork look ok, but i gave up on doing anything else as I did not want to cause any more damage.

I am getting all my winter kit together just now and thought there might be a way of resolving this. Does anybody have any ideas. I had a look online and there is a guy that drills large holes and fits something that looks like a tightly coiled spring which he then screws into. Is this a realistic option and if it is what are these things called.

Any help would be great or I'll be getting soaked again this winter.

5 comments

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jova54 [681 posts] 4 years ago
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It's called 'helicoiling' and any competent engineering firm should be able to do that for you.

It might also be possible to remove the old bolt stub using an extractor screw which is basically a left-handed screw which you screw into a pilot hole in the end of the bolt. As you tighten the screw up in will/should unscrew the bolt.

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edd23 [47 posts] 4 years ago
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Just wondered how you got on removing the bolt? I have just done the same thing  20 20 Sheared bolt is not causing any issues and bike is easily still rideable but as I live in North of Scotland mudguards are essential for the next 5 months or so...

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harman_mogul [303 posts] 4 years ago
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Extractor screw should work but tricky with such a small bolt. Could try drilling out from rear of guard eye -- drilling imparts a lot of torque, so there's a good chance it will unscrew. PlusGas first, of course. Otherwise, get a framebuilder to do it.

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Swami Dave [58 posts] 4 years ago
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I've done the exact same thing with my rear SKS guard. Tried sawing a cross head into it but it's jammed tight. Plan is to drill it out but if there's enough showing through on the other side then it may be possible to grip it with pliers and twist it out. And then heavily grease the new bolts...

I'll let you know how I get on with the drill.

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edd23 [47 posts] 4 years ago
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Bike now booked in a LBS to get them to remove sheared bolt, I not confident about drilling it out without causing damage, will get them to fit the mudguards at same time  1