Broken Bolt

[mr48chev]

Is it bottomed out in the hole or just over torqued and snapped? If it isn't bottomed out or crossthreaded and bound up and is close to the surface you may be able to take a center punch and a small hammer and gently unscrew the broken part. Just start with the punch close to one edge of the end of the broken bolt and tap it with the hammer so you are turning the broken piece counter clockwise. If it turns, once you get it up above the surface enough to get vise grips on it or screw a nut down on it an weld the nut to it.
This won't work if it is in a real tight bind, cross threaded or bottomed out though.