Taking Yokes of a D300

I need to take of the Yokes from my D300, the problem is the nuts that hold them are too tight and I dont have the D300 in my rig yet, so when I try to loosen the bolt, it just keeps turning with the yoke. So how can I loosen the bolts that attach the yokes on the case? has anybody done this before. I know I probably could do it with an Impact gun but I dont have access to one.