Hi Scotty, got a 2000 Mercedes SLK230 with 186,000 miles. Lately, whenever I turn left on the steering wheel about a quarter of the way sometimes I will feel some weird grinding/rough feel coming from the steering. Sometimes there is a slight groaning noise accompanied by it, but the sound is very subtle.  This happens when making a hard left turn going above 15mph. Turning at a very slow speeds doesn't cause anything. You can also feels these effects more especially when making a U-turn. Turning right doesn't have any weird feeling. Another thing to note is that the feeling is only a quarter of a turn, once I rotate the steering further, the feeling goes away. 

The tires are only a year old and I replaced the power steering pump/fluid a couple years back. I am suspecting wheel bearing perhaps?

Whenever this happens while driving, It feels like something physical in the suspension is causing this. When going straight or at freeway speeds the steering feels fine going left and right. This only happens when doing left turns at an intersection on a busy street.