It was explained to me that this component is the Mercedes solution to an A arm in these cars. The thrust arm is he part that projects rearward into the subframe? and inserts into a box (bracket) that is bolted to the subframe. It takes the rearward force of braking. If this component is shot than there will be alot more noise. Of course, I really dont know what I am talking about here. I am jut repeating what my Indy told me.