Specialty Products Company (SPC) 47242 Jeep Caster Shim 1/8 inch (Case of 6). These shims provide positive caster changes on early model downsize Jeeps by installing them between the lower control arm and the frame bracket. It is for larger changes. Its applications are: Jeep: 1984 - 99 Cherokee, 1986 - 94 Comanche. 1/8 inch thick. It is a case of 6.