Ground clearance adjustment (Mercedes-Benz E-Class W210)

E-class cars are equipped with clearance control (ground clearance), which allows the rear of the vehicle to maintain a constant ground clearance regardless of the load. Thus, even with a full load or when driving with a full trunk and trailer, the vehicle's driving performance does not deteriorate, which has a positive effect on active safety. On vehicles equipped with a ground clearance regulator, the regulator's oil pump is installed directly behind the power steering pump. Sometimes it is called a "tandem pump" because both pumps are driven by one shaft. The ground clearance regulator pump pumps the working fluid from the expansion tank and can, with appropriate resistance, create a pressure of up to 200 bar. Then the working fluid under pressure flows from the pump to the pressure regulator located on the rear suspension. The regulator is connected to the rear suspension stabilizer - this is how the vehicle's load is determined. Depending on it, the regulator opens or closes the corresponding valves for the working fluid.

The following operating states of the clearance regulator are possible:

1. Filling. When the vehicle is heavily loaded, the regulator lever moves to the upper position and the working fluid is supplied to the storage tanks on the shock absorber struts. The rear of the vehicle is raised until the lever again occupies the middle position. If the load is so great that the lever does not return to its original position, the safety valve limits the pressure in the struts to 150 bar.



2. Drain. In this case, the regulator lever is in the lowest position. If the rear of the car is unloaded, the working fluid flows back from the struts to the tank, the rear of the car is lowered. In the struts, however, a pressure of 30 bar is maintained to perform the damping function.

3. Middle position. The working fluid flows from the pump through the regulator to the tank with almost no pressure.

(Text republished from the website: mercedesman.ru)

Checking the clearance regulator

1. Check the level of the working fluid in the tank - it is located in the engine compartment on the left and also provides the power steering. When the car is normally loaded, the level should be between the "MIN" and "MAX" marks.

2. Use hydraulic oil for topping up (take it to the official service station). Use the fluid indicated on the reservoir: hydraulic oil Zentralhydraulikoel (Nr. 000 989 20 03/10 for one-liter containers).

3. If the fluid level in the system drops regularly, check the tank, pump, regulator, storage tanks on the struts, and shock absorbers. It is easier to detect the leak when the engine is running.