I replaced the whole shackle because of the problem with the end plates. I had no way to drill the proper sized taper or I could easily make one. I replaced all of the bushings, new shackle pins, new springs with bushings installed, and perhaps most importantly the special bolts retaining the non-shackle end of the springs. Front and rear.
I mention the special bolt because mine looked fine externally and seemed to be holding the spring just fine. When I disassembled mine I was surprised to see the hollow bolt was worn almost completely through on both rear bolts. The rear suspension of my truck apparently got quite a workout over the years it was on the road. By contrast, the shackles, bushings, bolts, in the front end seemed barely worn and they were original.
Chuck
