Here is a preliminary post-tensioned king pin concept. The idea is to use a chro-moly steel sleeve with a smaller high strength bolt inside. The sleeve is sized to just bottom out at the desired bushing compression. Then the bolt can be torqued up to a high value to place the sleeve into a high compression load. Then in use, the loading on the sleeve will stay under compression loading instead of swinging from tension to compression as a typical king pin bolt is loaded as the truck turns side to side. But you can see the steel sleeve, the bottom cap that supports the bottom of the sleeve and the smaller bolt that fits down inside the tube. This is similar in concept to how things like bridges are built where steel rods inside the concrete are post-tensioned to keep the concrete under compression load at all times (concrete is weak in tension, but strong in compression). The idea being that cracks in the steel grow when the steel is under tension as happens on the outside of the bolt when the truck turns to the other side. So will try and get this set up in a truck and give it some test rides to see how it works.   (70/70)