The stud is a self locking taper. It spins because the matching female taper is damaged. The stud wont lock and loosens with use. Life would be a lot easier and probably cheaper if you bought a new case half.I installed a new one, added a washer on the bottom. Tightened it real good. Was solid for about 2 days (16ish hours). Now sloppy again. May take off and add some shims as suggested. When they are new they are tight and easy to tighten the nut on. But once they are used and loosen up, how do you get the nut tight without the stud spinning?
Dan