CDNbkrdude

Any suggestions on the best way to remove a stripped rotor bolt? The head is rounded out and it is virtually impossible to get any grip on it. I've thought about putting a slot in it to use a regular screwdriver, putting on some penetrating oil, etc. but thought I would check here first.
Any suggestions would be helpful.
Thanks eh!

Retro Grouch 

I'm thinking it must be an allen bolt rather than torx. If that's the case, try a brand spanking new allen wrench. That'll work more often than you'd think. Then throw your old, work allen wrench away. Allen wrenches don't last forever and worn ones cause more problems than they're worth.

sch

Depends on how much maneuvering room you have for tools. Sounds like either
a phillips or allen head screw? Slot would work but making a good one is not as
easy as it sounds. It is easy to round over or slant the slot sides so that the
screwdriver bit cams out. Dremel tool with a very thin ceramic/alox grinding/cutter
wheel would be a good start. Try slotting a similar screw elsewhere first to get some
practice in. Another option would be to grind flats on either side of the screw (make
sure they flats are parallel!) and then use a small adjustable wrench to turn it out.
If this is an allen socket the next larger size can sometimes be forced into the rounded
out hole (eg 5mm hole rounded out, use 5.5mm allen head -- if you can find one, some
of my sets have them, some don't) but this approach assumes the use of a hammer
or press, neither likely to attractive or feasible options. Phillips head could be drilled
out to a round hole and same approach tried. Finally you can drill the screw with a
drill just smaller than the threads and try an easy out, a sort of hardened taper with
a couple of helical cuts on it in a L hand rotation that is wrenched into the drilled
hole and once it bottoms on the taper it grabs the screw and torques it out. Sets of
these run $5-10 at hardware stores, Lowes, HD or Sears. Steve

Rev.Chuck

First if the stripped bolt is an allen head, drive the closest size torx head into it and try that. I would also heat it with a propane torch if you have one. Not red hot but hotter than you want to touch. This will help release the loctite that is used on these screws.
If it is a torx, get a dremel and put two of the thin cutting discs on it, this is to get a slot wide enough to put a screwdriver blade in. cut into the head right up to the rotor. If you put a screwdriver right on it, the slot cutting will have put enough heat into the screw to free the loctite, other wise heat it again with a torch or even a lighter.