The design and operating characteristics of MB power windows has been very consistent throughout the 70's and 80's. What exactly is the problem(s) you are having? Do a search here and you will probably find lots of relevent threads. Most issues are either mechanical or electrical, and given the age of your 280, probably a heaping helping of both. Also, I believe Haynes would have a manual that would cover your chassis/engine group (but likely might only have procedures for removing and replacing assemblies and major parts)
