Tips on how to get rusted u-bolts out of trailing arms needed

[MT71c-10]

I tried a search about this but came up with nothing. I'm in the process of adding a lowering block to my 71, and ran across one side of the u- bolt is rust-welded to my trailing arm. Does any body have any ideas on how to get this stubborn boy out? I've already messed up the threads on the u-bolt too much so I can't try the double nut and big cheater bar meathod. It's been soaking in penatrating oil for 24 hours now, and my bonehead put some visegrips on it and smacked it with a deadblow and got nothing.Any ideas are welcome. Thanks!