Quote:
Originally Posted by goldstone
Thank you both for your helpful replies! It makes sense that the level-control valve necessarily checks backflow from the struts and accumulators, and this certainly seems the most likely source of symptoms my 560SEL is exhibiting.
 But...
I'm not seeing how excess forward flow is "checked". At what point in the system circuit is desired pressurized hydraulic fluid in the struts and accumulators prevented from simply bleeding out toward the reservoir bottle in the normal forward direction? After the accumulators, does the circuit somehow route back to the control valve again to accomplish this regulation? Or is some other mechanism involved? (Clearly there's some way this is accomplished back there, since the reservoir canister up front is not pressurized.)
Thanks again for clarifying how all of this works. |
The question presupposes that the hydraulic fluid is continuously circulated thru the strut/accumulator system; it is not. When the control valve is in the neutral position, pump output is directed back to the reservoir. When in the neutral position the control valve serves to isolate the pressure supply from the struts/accumulators. The struts/accumulators can be viewed as being at the end of a dead end branch off of the circulating loop which consists of the reservoir>pump>valve>reservoir.
To raise the rear suspension the control valve allows flow into the struts/accumulators. In addition to returning the strut to normal ride height length, the fluid inflow also displaces the diaphragm in the accumulator, and in so doing increases the operating pressure within the strut/accumulator system. The contrary occurs to lower the suspension.
The flow into/out of the strut/accumulator system is quite small, less than 500cc full cycle.