side of compressed air delivery device 1 where it flows via air discharge dryer device 2 check valve 50 changeover valve device 3 and bellows valves 60 61 62 63 into air suspension bellows 64 65 66 67 in the process the resulting level height is monitored via displacement sensors 68 69 70 71 by control unit 5 when a desired level height is reached at one of air suspension bellows 64 65 66 67 control unit 5 switches the bellows valve 60 61 62 63 upstream from that air suspension bellows into shut off position when all bellows valves 60 61 62 63 have been switched to shut off position in this way control unit 5 turns electric motor 6 off and switches accumulator valve 8 into shut off position and the process of filling of air suspension bellows 64 65 66 67 is complete besides filling of air suspension bellows 64 65 66 67 it may be appropriate during startup of the air suspension system also to fill compressed air accumulator 9 which initially is at atmospheric pressure for this purpose communication between outlet port 106 of compressed air delivery device 1 and compressed air accumulator 9 is established by means of changeover valve device 3 accumulator valve 8 is switched into open position while bellows valves 60 61 62 63 are left in shut off position electric motor 6 is then turned on whereupon compressed air delivery device 1 begins to deliver compressed air compressed air delivery device 1 then sucks in air from the atmosphere through air intake device 4 the sucked in air is discharged on the outlet side of compressed air delivery device.