Looking for help/information on how to adjust the spindle zero on a Cadillac PLA-CHEK 10074. There is a set screw on the spindle that I thought would allow it to turn/adjust but it would not move when loosened. I'm not sure if that isn't how it's done or if it's just frozen. I've checked it out at each step and it is the same .0004 off at each and in good usable condition. Also, does anyone know where you could get a manual or original specifications? Thanks! Tom