2001 C320 what do I need to replace to bring it back to smooth ride. Makes a thud sounds when running into sharp bumps, like metal to metal.

 

Can't really say what is wrong without an inspection.

Get it on a ramp and carefully look at all the suspension bushes and also the exhaust system.

This is not a "normal" problem so I suggest that since it is possibly SAFETY related you get someone who is use to checking cars over to view.

Advise outcome of inspection.

Stuart