Looks like Ed Richardson has part of your answer. Antifreeze and brake fluid replacement. I'm sure that there were other operations too, but this gives you some help.
Flushing the cooling system and replacing antifreeze doesn't have to be done by a dealer. This is a good do it yourself project, or could probably be done at the "Jiffy Lube" for less cost.
Changing Brake Fluid is not usually done by most people, but it really is a good thing to do if you plan on keeping your car long term. That too is an operation that could be done more economically at an independent garage.
There are many things that are best done by people who are experienced and familiar with the breed. But standard preventive maintenance operations such as these are much more economically done at home or in an independent shop that you trust.
'84 Euro 240D, 516K miles
'88 300E 5 Speed
Over 800,000 miles in