I used PB blaster. I would stay away from vice grips, don't want to make any burrs on the bolt. if you weiner the socket on the bolt you should be able to work it in and out to try and get the lube inside further and further. Once you get it out be sure to clean all the penetrating oil out so it doesn't affect your new bearings. Be sure to get all the rust off of the bolt. I put a little coating of wheel bearing grease on the bolt when I put it back in.
http://www.jalopyjournal.com/forum/threads/best-penetrating-oil-for-stuck-nuts-bolts.773380/
Interesting read, going to try the acetone/ATF mix and see does it help