Rear body bushings replacement

On most uni-body type vehicles, these sub-frame bolts thread into a "captive nut" that's actually welded in place inside the body/frame rail. If the bolt is turning but not coming loose, that generally means the captured nut has broken loose and is spinning inside the frame rail. There's no official way to fix something like this. Most technicians look for an appropriate area on the body/sub-frame rail to cut an access hole to repair the nut. I can't say exactly where this should be done as it differs from vehicle to vehicle. It also requires cutting and welding a structural part of the vehicle, so it's something that should be performed by an experienced body technician.