HELP! spun a braze-on rack mount

The fitting is a kind of rivet (known as a rivnut) that is fitted by compression, not brazing/gluing etc.

Unless the bolt is well and truly seized in there, you should be able to remove it by gripping the part of the rivnut that protrudes from the frame by 1mm or so. There is not much to grip but a pair of mole grips or other clamping pliers should give you enough purchase. Two pairs of hands help, as does a good soaking of anti-sieze, WD40, GT85 etc.

It's tough to do this without spoiling the paint on the rivnut, but paper under the mole grips should protect the frame.

Once the bolt is removed, the rivnut can be tightened using a specific tool that your bike shop could well have. Or just wing the bike in to them, bribe the mechanics with doughnuts/coffee/wine and see if they can do the whole job.

If you already have a rack attached and can't get a tool in there you could be in for some fun and careful drilling may be the solution.

Good Luck

It's an extreme method, if all else fails. But, if you heat up the rivet with a blow torch, it will expand, forcing the sides of the rivet against the frame and you'll be able to unscrew the bolt. It'll only work if the hole for the rivet is the exact same size as the rivet though. It'll also screw up your paint job too.

thanks for the replies, Was thinking along the lines of some wd40, shoulda used that in the first place. hindsight is 20/20.
i'll let you know what happens
Tim