[speeder]

I've never heard anyone refer to the vacuum systems on a Mercedes, (or any other vehicle), as "pneumatic." That term is usually reserved for systems that are actually pneumatic, like the air suspensions on several MB models throughout the years. Systems that run on compressed air.

To avoid confusion, we just call the vacuum systems and components "vacuum". And the vacuum systems and components on older Mercedes are serviceable if you know what you're doing and have the right tools and equipment. Depending on the sub-system, it can either be fairly easy or absolutely maddening. The climate control on my 1980 w123, (early style system), is almost completely vacuum controlled and leaks can be extremely difficult to hunt down. Door lock systems are easily diagnosed, in comparison.