Rounded front axle clamp bolt

[jchesshyre]

Heeeeeeeeeeeeeelp!

What do I do? Tried tapping it round with a centre punch - no joy. No space to get mole grips on it.

[tony.mon]

Drill the head off, then use a broken stud extractor on the remaining threaded part.
If you can, use a left hand drill bit, there's every chance that it'll grip the screw head and wind it out if you use plenty of wd40 in the split and on the rear of the fork leg.
You'll have to thoroughly degrease the disc, and be careful not to get oil on the brake pads.

[VTRDark]

I would first use a bit of heat to help but hammer a bigger bit in there and hope that it bites enough for you to be able to undo it. Maybe use an impact driver. Last resort would be to drill it out. They are pinch bolts. One would think the clue would be in the name when it comes to tightening them up..

[Wicky]

Hammer in a dispensable torx socket bit and see if that will get it to turn.

[jchesshyre]

Thanks guys. I will try these things, maybe starting with a disposable torx bit and then a drill.

It hasn't happened because it was over-tightened, I was just distracted while undoing it and didn't notice that there was crud in the bottom of the hex socket which meant the Allen bit hadn't seated properly.