I am having a problem with our 01 C320. Basically when the car is running over bumps the front end would produce some knocking sounds. After searching the forum I have found the possible causes of the problems:
-- The front struts or any of the bushings
-- The sway bar bushings and end links
-- Lower Ball joint or Control Arm upper ball joint.
-- Wheel bearing
-- The axle shaft
When driving normally on a smooth road the sound is mostly not there, but when the car is driven on rough road bumps the knocking sounds would get serious. I feel that there is something that is loosen. The power steering rack of the car was replaced not long ago.