Grind a screwdriver bit so it's a very snug fit in the slot, and use a pair of vise grips on the screwdriver shank to turn the bolt out. A little heat with an acetylene torch on the carrier housing in the area of the bolt won't hurt anything and might help it break free.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!