Losen those nuts off all the way (counter clockwise) before you take the wheels and tires off. I used a big fucking pipe wrench and put a two foot pipe over the handle to get more leverage on them. When you put them back on put alot of lock tight on both axle lock nuts .
http://www.bluetraxx.com/ go there and then to tech tips, then look under rear axle bearing replacement for a guide. Also, use your clymers manuel.