It looks like there is still one screw with a head. Will it come out? If so, remove it and put some PB in the hole and tilt the frame enough to let the PB get to the underside of the broken bolt. My experience has been you cannot use too much penetrating oil.
I agree with Jerry [quoteOnce you get the bracket off, hopefully there will be enough of the screw protruding above the frame to grab with a small pair of vise grips. If so, use plenty of penetrating oil, and gently work the stub back and forth- - - -don't try to muscle it out.
][/quote]
Good luck
Harold
