both my Bronco and my F-150 popped as described and they were both due to a bad radius arm bushing. The bushing is split into 2 parts, the forward and aft part. In both cases, the forward part had disentigrated, but still looked fine when I crawled under the truck. I only found the problem when I installed the lift kits and was replacing the bushings. They retail for about $10.00 in town and even if they don't need replacement, the aftermarket ones are a ton better than the stockers.