I have the collected set of diagnostic manuals & wiring diagrams all that in loose-leaf format for the W129 & W140 cars. Some of it may be relevant to you. They were dealer only items.
I also have the Information Access CDs, which are classroom service training material. They give you an in-depth look at the car w/o actually getting your hands dirty. In other words, they don't tell you how to change your oil, they just explain were it goes once you put it in.