When I purchased the S430, I knew that the air shocks would have to be addressed at some point. Overnight, enough air leaks out of the suspension that the car lowers itself about two inches. Once pumped back up, the car rides at the correct level and doesn’t cause any problems until I am driving downhill. At that point, a warning appears on the dashboard telling me to get the ABC system serviced at the dealership. Sound familiar to you?
Apparently, this is a common problem with the W220 version of the Mercedes-Benz S-Class. In fact, you can read forums articles for several hours about this problem if you wish. For my research, I read portions of Leaking Front Struts at BenzWorld.org. There seem to be three possibilities: (1) replace the airshocks, (2) convert to conventional shocks/springs, or (3) fix the leak at the top of the shock tower.
The first two options are rather expensive, so I am opting for the third. The kit is available at your local Mercedes-Benz dealer and the instructions (as posted at BenzWorld.org) are available here. If I don’t change my mind before then, I am hoping to have the repair completed this Thursday. We shall see.