stanley 82901 router base

I have a Stanley router. The model (not sure which # ) 90008 or .02 , 6.0 Amps, 23,000 RPM, with a 82901 base Model .01 The threads in the base for the locking screw ( 1" dia Fine Thread) have given way and I am unable to lock the router to the base. The screw in a Yellow Plastic and...