Drill a hole in one of the flats of the bolt head and stick a pin punch into it to prevent it from turning. Once the part is off the backing plate it might be possible to use some kind of a puller or a slide hammer on the spring anchor to get it out of the bracket.

"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!