Hi all, 

 

I've just purchased a 2017 LK 280 Estate and I've got this metallic knocking when going over deviations in the road at normal road speed, crawling it's fine.I can't feel it through the steering wheel and I can't find anything loose, worn bushes, no broken springs tails, loose backing plates etc. car is equipped with DCC. 

 

Bit lost what to check next. Did wonder if there is something loose within the dampers?

 

I've found this YouTube video which is the same but no comment or response from the owner. 

 

 

Edited 12 May, 20242 yr by sb1111

It sounds more like a rattle rather than a metal-to-metal sound, but it’s impossible to be sure. 
Can you, or better still a passenger, try to ascertain where the sound is being produced? Turn off the AC, retract the load cover and drop the rear seats too.

Yeah it's really odd. It's definitely coming from the front suspension. I purchased some Delphi drop links on the off chance it's them but doubt it is. I'll take for a spin at lunch. 

Here is my actual car and the crazy noise.. I can't track it down.

 

https://youtu.be/v752RPGqgNg?feature=shared

Definitely sounds like a loose bracket or other type of fixing. Did you buy from a dealer?

Edited 13 May, 20242 yr by numskull

Unfortunately Not from a dealer.

Usual suspects would be top mounts/bearing and bottom arms. My front lower arm rear bushes had that much flex in them, they were allowing the arm to make a metallic noise when it moved enough to make contact with the subframe. 
Most other items should have enough obvious play when checked with a bar or by hand, drop links, heat shields etc. 

Been up on the ramps at my local indy, They cannot find anything lose, worn bushes etc. They agree there is something as they road tested it and heard it but cannot guarantee its anything without swapping parts out to see if its this or that.. 

 

I'm wondering if there is something lose in the DCC damper? It had new dampers 60-70k ago as the old one were leaking. If it is the dampers how would i test it without swapping it out and just part cannoning parts onto it? 

 

Also OEM Monroe at £165 a corner or Billiesteins at £315 a corner.

Bilsteins. Could be the top mounts rattling if nothing else is obvious. 

I think I'm going to strip the suspension down and see whats what.. if i can get the damper off and give it a good shake to confirm its not that.

 

I may get some top mounts and swap them out. 

I think I've found it. New set of dampers are on order. 

 

https://youtube.com/shorts/wGsukDRcuus?feature=shared