Pneumatic suspension system for automotive application in which sprung and unsprung masses are supported by variable volume air spring units and incorporating compressor and exhaust valve devices for supplying an exhausting pressurized air from the units to adjust the height between the masses. A Hall effect device effective across a pressure boundary senses the position of a magnet movable within one of the air spring units and reflects relative movement of the sprung and unsprung masses to effect control of the supply and exhaust of air from the units. By axial movement of the Hall device, dead band width can be established to accommodate normal ride motions between sprung and unsprung components. By rotating the Hall device at any axial position, the vehicle bumper height can be selectively increased or decreased.