Hello Tony,The rear hydraulic suspension uses the same oil as the power steering. MB recommends to use oils from quality sheet 344.0
There are some tricks with filling the system. But i would suggest to find a independent Mercedes workshop. They will have the needed tools and workshop instructions to do the job properly.
Once the leaking component is found, indie or any authorized dealer will be able to order the part for you. Indies might be willing to have the leaky pipe or the hose done at hydraulic shop.
I am here to assist you more if need be
Very many Thanks......my leak is at the front of the car.....and to be honest I didn't know I had hydraulic suspension. Is this front and rear? I am told that a pipe going the length of the car may need to be replaced?