Expedition 2WD V8-4.6L SOHC VIN 6 (1999)
Air Spring: Description and Operation
RAS vehicles use air springs in the rear. The air springs provide a varying spring rate proportional to the system' s air pressure and volume. The air
suspension system regulates the air pressure in each air spring by compressing and venting the system air. Increasing air pressure (compressing) raises
the rear of the vehicle while decreasing air pressure (venting) lowers the rear of the vehicle. Vehicle height is maintained by the addition and removal
of air in each air spring through an air spring solenoid installed in the upper spring cap and energized through the air suspension control module.
The two air springs replace the conventional rear coil springs.
