update:
no it wasnt the bearing. so i guess for those who are about to replace that please wait and get it diagnosed
it turns out that it was the rack / pinion. the joint where the pinion attaches to the rack had become lose and was making that noise.
mercedes has a kit for it. kit is about 150 but the 4 hours to take the rack out and in is what costs the most. noise gone. lesson learned: sometimes it's best to let the dealer diagnose and do the job
