There's a ball joint at the bottom of the SLS shock where it attaches to the control arm... they wear out on high mileage cars and give a harsh ride and knocking sound (and feel) over bumps (assuming the accumulators and the rest of the system is OK). That's what is currently the situation on my 560SEL. Will have to replace both $L$ $hock$ to repair it on my car.

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Erich Loepke
2010 Ford Focus
Currently Benz-less