Mate take note of what Paul and Tony have written.
I note that you only have 1 post so not even sure you are still about??
I have to say that my last resort for undoing stuff is one of these EzyWrenches from KCI
http://www.kcimports.com.au/item.php?i=31#gallery
Mate i have never found a nut that i could not undo with that little gem. I have cracked an Alternator Pulley while resting the Alternator in my other hand without holding the pulley...CRACK!!! and your done.
Big Winner for me.