Air suspensions have been used my many vehicle manufacturers, including Audi, Bentley, BMW, Buick, Cadillac, Chevrolet, Ford, GMC, Hummer, Jaguar, Land Rover, Lexus, Lincoln, Mercedes-Benz, Mercury, Oldsmobile, Pontiac, Porsche, Saab and Volkswagen. Air suspensions typically provide a smooth, luxury ride while offering the ability to maintain or even change ride height for automatic load leveling. The air suspension may also work in conjunction with electronically-controlled shocks to vary the ride and handling characteristics of the vehicle.
An air ride suspension may have air springs with conventional or electronic shocks or struts, or use air bladders inside the shock absorbers or struts. A small onboard air compressor supplies air to the air springs, shocks or struts when additional stiffness or ride height is required, while solenoid vents release air pressure from the system when less stiffness or ride height is required.
Over time, rubber air springs and bladders can lose their elasticity as they age. This can lead to cracking and air leaks. Air leaks may also occur in the lines that connect the compressor with the air springs, shocks and/or struts, or in the vents. A gradual or steady loss of air anywhere in the system means the compressor has to engage more often to make up for the lost air. This can overwork the compressor and lead to compressor failure. Consequently, if the compressor has failed on a vehicle with an air ride suspension, chances are the cause of the failure was air leaks in the system. These air leaks must be found and fixed before the new compressor is installed, otherwise it may suffer the same fate.
A new air dryer should also be installed when changing a compressor, springs or shocks/struts to keep moisture out of the system. The dryer absorbs moisture. This helps prolong the life of the compressor and solenoids.
On older vehicles with rubber air springs, all of the springs should be replaced as a set if one or more springs are cracked and leaking. Ditto for air shocks and struts, and leaky air lines.
Another source of trouble on air ride suspensions are the ride height or deflection sensors that are used to monitor chassis movement and height. A bad sensor may cause the air system to overinflate or underinflate.
Replacement parts for air ride suspensions are often more expensive than conventional suspension parts because of their design. So, for older applications where the vehicle owner may be reluctant to replace such expensive parts, a repair alternative is to convert the air suspension to a conventional suspension with a special conversion kit. Such kits include steel coil springs to replace the air springs, or conventional shocks or MacPherson struts to replace the air shocks or struts on the vehicle. A conversion obviously eliminates the advantages of an air ride suspension but provides the same basic function and ride control as an ordinary suspension.