Take your jack and press up on the lower control arm pushing the knuckle back up towards the ball joint, that will create pressure to keep it from spinning. You will have to tighten the bolt back up snug like it was when you started and then lower your truck back down onto the jack stands with the bolt snug. After you do that you should be able to take it off no problem if you dont stop taking the bolt off. Give that a try and see if it works. It should! Good luck!