On my passenger power seat, on the track that the seat goes back and forth on, when I put the seat all the way forward to get something from underneath, a ball bearing or two will fall off the track. The others get pushed forward with the seat, I guess, but there's always one or 2 that are left behind, and eventually fall off the back of the track, in the rear footwell area.

What is causing this, and how to fix?

Thanks,

Jeff 1991 300d, 111k