Bolt removal. Need help.

[Ddan]

If it were mine I would use a brass drift and lightly tap on the stud until it straightened enough to fit the flange on. Gently bending it is better than using a lot of force if possible, moving it a little at a time allows the metal structure to relax instead of break.
So how do you suppose it became bent in the first place?

The OP probably sorted it out, oh, 3 years ago