I just replaced my wheel! Indeed that allen bolt was tight! Could not budge it with a regular allen wrench and a cresent wrench. I bought a 3/8 drive 10mm allen socket and used my air impact tool. I just slowly pulled the trigger and a couple of wacks of the air tool and it came right out!
Was a piece of cake and yes I think there is locktite on threads.
Be safe if airbag equipped and disconnect the battery cable!!!!
Smokie