Worn steering/suspension?

My 1987 300SL has a nasty habit of wandering over the road especially on changing road camber. All wheels aligned by MB recently including adjustment of steering box. Also sometimes makes a noise like something is touching wheel at low speeds when steering at full lock. Been checked by MB on ramps but they reported nothing. Could something be slack or worn causing movement at front end? No sign of unusual wear on tyres.

Any ideas?

Thanks