While tightening (gently) the third screw on a new distributor cap, the
screw (brand new and obviously defective) sheared and broke off at the
surface of the hole on the body mount. For the moment the car operates with
two screws holding the distrib but I know this can't be good.

Anyone with a similar experience find a successful way to remove the butt of
the screw threads from this fairly confined space? I appreciate your ideas.