You must be talking about the rears. I just went through this Sunday, and my right rear one was stuck just like yours. I shot WD40 into it as much as possible. Then with a long extension, 18mm socket and a breakerbar, I just worked the bolt back and forth in 1" swings until it started to move (the first time, I tried to man-handle it and snapped the tip off a no-name extension I was using, DOH!). Once broken loose, then I basically unscrewed it until it felt free. It's just gonna be about 10 minutes of being methodical and taking your time working the bolt out. Then wire brush it once removed, regrease and reinstall.