Two days ago my Baujahr 86 model 300d suddenly became very heavy to turn- and yes the PS fluid was missing.

NO sign of leakages from hoses, PS-fluid container or Vickers pump, but a lot of PS fluid on the bottom pan.

As a first start, I pured in some PS-fluid (after studying the thread about ATF-fluid as af PS-fluid on Mercedsshop) - but it came out almost as fast as it was poured in !
My conclusion is that the PS- steering house (is this the correct termonology) is leaking an most likely where the actuator- arm is extending.

Removing the air filter and palpating the steering house supports me in that (dry on the top and on the sides facing motor and steering wheel shaft).

From a spareparts supplyers homepage, I learned that a Servo steering house comes in two different shaft dimensions for my model BUT that is about it. NO other information than a more or less simple exploded drawing seems to be available.

My house bible (So wird's gemacht") does not say anything about the PS except for how to refille PS-fluid.

Where do I learn more about the PS house itself ???