PeachParts Mercedes-Benz Forum - View Single Post

dmorrison · #6 04-21-2003, 11:00 PM

Understanding the system will allow you to see why your problem is the Accumulators .
The pump at the engine provides the presurized hydraulic fluid that enters the line that goes to the ride lever control unit. That is the unit mounted in the back of the car. The control valve has a actuating rod that is attached to the rear sway bar. As the sway bar twists due to loads on the car which are transmitted from the rear suspension. This movement of the rear sway bar moves the control lever. This opens the control valve allowing fluid to enter the hydraulic "shock". The piston. The hydraulic shock is not a "shock absorber" it is an hydraulic actuator or piston. The controller tells the actualtor to rise or lower and the presurized hydraulic fluid does that. Once the hydraulic actuator is at the correct height the control valve "shuts off" the fluid. If that is all the system had then the car would sit at that height with out any ability to move. How the system allows for spring type of movement is to have the accumulator.
The Hydraulic fluid actually enters the accumulator first then bleeds over to the hydraulic actuator. In the accumulator thier is a diaphram on one side is the hydraulic fluid and on the other side is a gas. Remember hydraulic fluid will not compress. It is rather solid in this setup. The gas will compress and its the gas in the accumulator that provides the spring effect in your rear suspension. Why do you have coil springs then. The coil springs carry some of the load and the hydraulic suspension the other.
When the control valve is "finished" with the pressurized hydraulic fluid it goes back to the fluid tank in the engine compartment and is there to start the cycle all over again. The return line has a filter attached to it where it enters the tank. This filter should be changed occasionally along with the fluid.

Dave