Front or back? All you have to do is take off the caliper and hammer out the old broken one. Then goto an auto store and tell them you need a stud for the front or rear of a ? mercury cougar. To put in the new one. Slide the new stud in and put about 2-3 washers around it. Then put on a lug nut and tighten until the back threads are all the way through. Hope this helps.