W140s are VERY well build, and IMO, the most well build S-Class. However, early W140s suffer from shimmy steering wheel, which some may be addressed, but most don't. So, test drive the car is a MUST. Some other common things that may need attentions are Evop Core for A/C, Close-Assist Pump, window lift-regulator(I believe that's what it's called), other then those, there are no problems what-so-ever with the car if it's well taken care of.
BTW, there is a chance that the dash cluster may shorted out. At least mine did, and have it changed to newer type cluster with digital trip/odometer readout...
Find out as much history of the car as possible. Read through ALL service history if you have the access to them.
<LI>1992 Mercedes-Benz 400SE
<LI>Pearl Grey/Black Leather
Mercedes Owners ICQ ActiveList ID#61730549
Mercedes S-Class Page