My 1983 500 SEL has a real problem with the four point hydraulic suspension. It has always been sluggish to initially raise after a something in the system is changed.

Current Problem: Car lost pressure and will not raise.

1- Cylinders appear to work well with no leaks
2- The four support point Accumulators are new.
3- The Fifth Accumulator is used
4- The Control Manifold ( that connects to the dash cable )
is new.
5- The Hydraulic Pump # 1172360008 is used. I removed
it, cleaned it, and reinstalled. There is no visible wear.
Fluid exits in a steady stream, but with little pressure.
Fluid flow can be stopped by holding your finger over
the output hose end.
6- System filter has been cleaned, and new MB fluid added.
7- No leaks are present in the entire system.

I am thinking that either the pump does not put out
sufficient pressure, OR the control valve on the 5th
accumulator is not working properly.

I do not understand the function of the 5th accumulator or
control valve attached.

Does anybody have a solution to this problem ?