What pressurizes the hydraulic shocks?

[pcmaher]

I've been searching for technical details on the operational aspects of the hydraulic shocks on my 1995 S600. There is a lot of conflicting info out there. Does the power steering pump supply the pressure for the shocks, or is there a seperate pump? I know there are two seperate reservoirs for these systems, but that's all I'm sure about. I would really appreciate a knowledgeable person to bring me up to speed on how these systems work.

[plink49]

The power steering pump on the w140 with self-leveling rear suspension is termed a "tandem pump". One half produces the pressure for the steering and the other half for the rear suspension, but share a common reservoir of hydraulic fluid. The two sides are independent and produce/maintain different pressures. Keep an eye on the reservoir fluid level, as a continuing loss (of level) could mean a problem with one or both of the rear accumulators, which can lead to hyper-expensive repairs unless addressed before physical damage is done. I learned about these things the hard way about 6 months ago.

[SE300]

The W126 also uses a tandem pump, but two seperate reservoirs.

[pcmaher]

Originally posted by plink49
One half produces the pressure for the steering and the other half for the rear suspension, but share a common reservoir of hydraulic fluid.

plink49, MB calls out two different part numbers for the power steering and hydraulic shock oil. How can a common reservoir of fluid be used?