Control Equipment

D. Control Equipment





The level controller (3) is attached to frame floor by means of holder (8) and is connected with lever (6) on torsion bar (10) by means of connecting rod (7).

The bleed screw in distributor or level controller (11a) serves for reducing the pressure in system for repair and test jobs.





Owing to the elastic suspension of the rear axle center piece the level controller is installed from the left to the right.

Functional positions of level controller (version up to 8/85)





Neutral Position

Oil entering via feed duct (B1) is returned without pressure to fluid reservoir via return flow duct and return flow line (C). Return flow valve (3d) remains closed.

Filling Position

Control disk (3c) has closed return flow duct (C). Under influence of respective pressure, the oil is guided to the suspension elements via pressureless ball check valve (3f) and duct (B2). Raising of vehicle rear end into level position will once again attain "neutral". The system is protected against overload by the pressure relief valve 13g) which opens when the max. permissible pressure is attained.

Return Flow Position

Control disk has opened return flow valve (3d). This will lower the pressure prevailing in suspension elements. The oil flows through the opened return flow valve and via the fully opened return flow duct (C) back to fluid reservoir together with the oil delivered by pump. When the level position of the vehicle has once been attained, the control disk will close return flow valve (3d). Provision of the basic pressure required for function of spring Struts as shock absorbers is attained independent of position of controller by the outer compression spring of the return flow valve (3d) pushing the return flow valve out of range of control disk when pressure in suspension element drops below a given value, so that the pressure cannot drop any further.

Functional Positions Of Level Controller (version starting 9/85)





Neutral Position

Oil entering via feed duct (B1) is returned without pressure to fluid reservoir via return flow duct and return flow line (C). Return flow valve (3d) remains closed.

Filling Position

Control disk (3c) has closed return flow duct (C). Under influence of respective pressure, the oil is guided to the suspension elements via pressure less ball check valve (3f) and duct (B2). Raising of vehicle rear end into level position will once again attain "neutral". The system is protected against overload by the pressure relief valve (3g) which opens when the max. permissible pressure is attained.

Return Flow Position

Control disk has opened return flow valve (3d). This will lower the pressure prevailing in suspension elements. The oil flows through the opened return flow valve and via the fully opened return flow duct (C) back to fluid reservoir together with the oil delivered by pump. When the level position of the vehicle has once again been attained, the control disk will close return flow valve (3d). Provision of the basic pressure required for function of spring struts as shock absorbers is attained independent of position of controller by the outer compression spring of the return flow valve (3d) pushing the return flow valve out of range of control disk when pressure in suspension element drops below a given value, so that the pressure cannot drop any further.