I aquired this 2002 S280 a couple of weeks ago. Typical S-class ride when I test drove it- smooth as silk. After it'd been parked for two days on my driveway, I found that it had settled on all four wheels so it looked like the the old Citreon.. The warning on the dash was car too low- don't drive etc. After the engine had run a few minutes and I'd pushed the button to raise it, I heard and felt some dull thuds from behind. The car began to rise slowly after that. The warning cleared from the dash and I was able to drive off. Now it still settles completely flat when left overnight, but I don't get the the thudding sound before it rises. The dealer I bought it from tried to convince me that the rising and settling was normal on the pre 2005 models when they got old. I wasn't convinced though. The posts I've read seem to imply that it's either the relay or the pump that's faulty- any ideas anyone?