[Onizukachan]

Originally Posted by Daggers

Easiest thing to do in that situation (if you’re replacing rotors anyway) is to simply grind the head off the screw. If you leave the screw “shaft” in place, or not, it doesn’t matter. The new disc is held in place by the wheel bolts anyway. That screws job is just to stop the disc rotating as you put the wheels on (to make it easy to align the wheel bolts / disc / hub). So if you leave the stub of bolt there for the replacement disc, you’ll be lined up still. The screw is basically useless anyway!

And a lot of the time once the pressure is off it, it will turn right out by hand or with a channel lock type wrench.
I drilled one out with a big bit, and such was the case once it was done.