One of the unique advantages of Dynatrac HD Balljointsâ„¢ for the 2007-2015 Jeep Wrangler JK and 1999-2004 Jeep Grand Cherokee (WJ) is that they are rebuildable. And you do not need to remove the ball joints from the axle housing in order to rebuild them; they can be rebuilt in place with common hand tools. This rebuild kit includes new bearings, seals, clips and nuts as required by the specific application. All of the new components are the same high-quality of the originals. Each HD Balljoint rebuild kit includes all the parts necessary to rebuild a set of 4 Dynatrac HD Balljoints (upper and lower on both right and left sides)