comprise the working chambers 66 and 67 that are connected via the lines 68 and 69 to the lines 48 and 49 the manual positioning assembly 61 except for the actuator 62 has the same dimensions type of couplings or nipples and construction as do the level sensors 6 and 7 accordingly the manual positioning assembly 61 can be substituted for the level sensors 6 and 7 when the headlights are to be actuated manually conversely the conversion of a manual to an automatic and load dependent actuation is also possible without difficulty due to the identical dimensions of the hydraulic chambers 6 7 and 61 the hydraulic system shown in fig1 is a static system in which a static pressure prevails that is dependent on its magnitude upon the pre tensioning of the springs 54 39 and 55 39 in the positioning elements 50 and 51 during a uniformly increasing or uniformly decreasing load upon the axles of the motor vehicle the system remains at rest due to the counteracting deflections of the levers 4 and 5 except that the level sensors 6 and 7 exchange fluid via the lines 30 and 31 consequently the total fluid capacity of the four working chambers 24 25 46 and 47 remains unchanged however when either of the motor vehicle axles 1 or 2 are loaded more than the other then the total fluid capacity of the four working chambers 24 25 46 and 47 changes and.