Quote Originally Posted by LokiSays
I would say grind off the head of the bolt to make it square and use a adjustable wrench to try and remove it. Worked for me before. Hope that helps. Use the WD-40 to lubricate it.
Yes, this can work... and if you're good with a grinder/cutting wheel you could also easily cut the nut and just separate it from the stud/bolt.

GL with it!