Hello all

Recently broke the antenna off our 1998 Z3, tried a cheap repair before spending 100+ for a new base. The insert was a couple bucks. In this case it needed to be longer to still use the grommet, but radio does work properly, and longer inserts, or standoffs, are available. May need to drill out the nut shroud part, or file down insert, depending on insert used. Thread size is M5 x .8. Small hole was drilled to install a set screw to let antenna thread in without twisting.

https://youtu.be/ASsIdSSVuqI