HouseCallAuto 2/2/2013There are no rules here regarding how to get out of a jam like the one you detail. You use any and all methods. If you absolutely cannot get to the spinning nut that broke the weld, that may mean that you use a sawsall and gut the bolt or that may mean you make a hole adjacent to the spinning nut and then use a vice grip to hold the nut from spinning. There are so many hundreds of complications that we run into as mechanics and there is no substitute for a mechanic seeing with his own eyes the problem you are detailing to receive advice on what to try first. That being said, figure out a way to prevent the normally stationary nut from spinning. There are no rules.