Date registered: May 2019
Vehicle: 1998 W210 E320 base saloon USA version
Location: North America
Mentioned: 0 Post(s)
Quoted: 16 Post(s)
With modern dampers there is rarely that "presto!" moment where the car immediately loses all compression or rebound control and starts bouncing like a pogo stick.
I've had various cars with dampers from Bilstein, Kayaba, Sachs, Koni, and Spica. Modern dampers tend to lose performance gradually and it's difficult to tell from day to day -- but when I replaced my last set of Kayabas on another car, the difference was night/day. The old units were in fact worn out (at 320K km -- who knows if I'd be able to notice a difference at 100K instead?).
I don't think there's a magic number distance. I also don't think a bounce test (where you rock the car like we used to do when the world was young and we were full of wonder and hope, so many beers ago) is completely reliable *except* if the dampers are completely gone (and note: *not* if they're seized, which is another story). Also, yes, Mercs with the standard comfort dampers are a bit softer compared to something lighter and more firmly damped -- but they should not bounce around or wallow excessively. If you have a taxi on your hands it's probably OK. If you have a yacht it's probably not.