Usually on a deal like this we get a pry bar to pry out the part while wrenching. Otherwise a elect. 4" grinder w a cutoff blade. Are u using some kind of penetrating oil? On any ext. part on a car always tried to soak it down before removal. A impact is always good also. It hammers it off.
+1 this WILL fix your problem, make sure when you're spraying with the PB blaster that you tap the bolt with a hammer it allows the PB to work its way into the metal. WD-40 is not even in the same category as PB literally.