Loose roll bar

This is what a normal roll bar support mount in the rear of the car looks like.  The rod attaches the roll bar with the lower A-arm.  

This is what happens when the bolt (top arrow) falls out.  The rod drops and gets tangled with the drive shaft. 

The rubber doughnut on the drive shaft continued to pound the roll bar rod. I had just tighten that bolt the day before.  This happened during the last race on Sunday.