Possible Airmatic struts problem (but not sure)
I have a problem with the suspension (Airmatic w/o 4Matic) and really hope that more experienced members here can shed some light on my problem, as follow:
1) When I drive slowly (normal slow) perpendicularly over a speed bump, I feel the car 'wiggles' at the front and the rear as the suspension rebounds, while producing a muffled thump both at front and rear (I can feel with my feet on the floor when both ends thumps).
2) When I drive over the same speed bump at higher speed (say like you are in a rush and has no time to really slow down), the symptom go away.
3) At freeway speeds there is nothing to indicate anything wrong with the suspension.
4) No trouble codes appear on the car's screen, and none also came up on the workshop's diagnostic computer.
5) I can still raise the suspension normally with the button ('Airmatic Rising' message came on about 25-30 seconds).
6) I can still feel the difference in stiffness when I select Sport 1 (firmer) and Sport 2 (really stiff).
7) In Sport 1, the same symptom still felt over speed bumps.
8) In Sport 2, the symptom completely disappear.
To note, the front suspension has some ball joint(s) wear.
My regular workshop said that this is a symptom of the Airmatic bags are going bad (minute leak). However, if this was the case, wouldn't going to Sport 1 & 2 will result in same symptom? Or is this more mechanical (like bushings or balljoints)?
I don't mind replacing the struts if need be. But I don't want to replace it unnecessarily.
Any advice and guidance is very appreciated.
Many thanks,
Renaldi
I had the balljoints checked and they are fine. It seemed the air springs (bags) are also fine but the shocks had some play at the last few inches of travel. So i replaced them with Arnott's coil spring kit and the problem thankfully went away.
Thanks all.






