1989 Rover 3 Series Eletronic Air Suspension

FRONT & REAR SUSPENSION
Front suspension consists of a front drive axle, held in position by 2 radius arms and a torsion bar. An anti-sway bar and shock absorbers are used to control body movements under all conditions. An electronically controlled air spring, located at each front wheel, is used to support vehicle weight and to control vehicle height.
Rear suspension consists of a rear drive axle, held in position by 2 trailing arms and a torsion bar. An electronically controlled air spring located at each rear wheel is used to support vehicle weight and to control vehicle height.
The Electronic Air Suspension (EAS) control unit is located under left front seat. The EAS control unit controls vehicle ride height by adjusting volume in each air spring. The EAS control unit contains on board diagnostics.

Air is drawn through the inlet filter to the compressor and compressed to 137-152 psi (9.7-10.7 kg/cm2 ). Compressed air is routed through the air drier where moisture is removed and stored in the drier desiccant. Dried air passes through a non-return valve to system reservoir for storage. There are 3 non-return valves that ensure correct airflow and maintain air spring pressure if there is a reservoir pressure loss. A pressure switch signals EAS control unit to activate air compressor when system pressure is less than preset limit.
When EAS control unit determines that an increase in height is necessary, the inlet valve and the relevant air spring valves are energized. When EAS control unit determines that a decrease in height is necessary, the exhaust valve and the relevant air spring valves are energized. A solenoid diaphragm valve directs all exhausted air through air drier. The dry, exhausted air purges moisture stored in air drier desiccant and regenerates the air drier. The exhausted air passes through a silencer mounted under the valve block to atmosphere.