The basics of an air suspension system and its parts

Air suspension, also sometimes referred to as air ride suspension, uses air pressure rather than spring force to maintain vehicle ride height. Air suspension has long been used in large shipping vehicles, but today it is used in many trucks, SUVs, and luxury cars. Air suspension systems have certain advantages over coil spring suspensions for these applications. First, air suspension can be adjustable, which allows it to change vehicle ride height and suspension stiffness for different loads, road conditions, and vehicle speed. This is useful in towing applications, and it can provide a smoother, more comfortable ride, which is why it’s preferred for many luxury cars. 

Typically, the front of the vehicle uses an air shock, which consists of an air bag that surrounds a shock absorber. The air shocks take the place occupied by struts or coil springs. In the rear of the vehicle, air suspension systems use air bags rather than springs to maintain vehicle ride height. The ride height or stiffness of the suspension is adjusted by air pressure.

The air is pumped into the air system by the air suspension compressor. This part compresses outside air for use in the air ride suspension. The compressor may be found underneath the frame of the vehicle, in the trunk, or in the engine compartment, depending on the model. Since moisture in the air can damage the air springs, the compressor must be used in conjunction with a drier. The drier passes the air through a desiccant, an absorbent material similar to the silica gel used to pack sneakers, in the packet labeled “do not eat.” 

How do I know if any of my air suspension parts need to be replaced?

One disadvantage that an air suspension system has compared to traditional coil spring or leaf spring suspension is that air suspension parts are more likely to need replacement. The rubber that the air springs are made out of is very tough, but it can wear out for a number of reasons. As mentioned before, it can be susceptible to damage from moisture. Extremes of hot and cold can also damage the rubber. Drivers in hot or cold climates are more likely to experience air spring failures than those in mild climates. The rubber could also be punctured by road debris. Any of these problems can cause the air spring to leak air which will make the suspension sag causing the vehicle to sit uneven or, if the leak is sever enough, the vehicle may not reach proper ride height. Air spring and air line leaks are the most likely cause of problems with the air ride suspension system. The compressor will pump constantly to try to compensate for the air being lost, which can lead to compressor failure.

Because air suspension parts are susceptible to damage and can be expensive to replace, 1A Auto offers kits on some vehicles to convert your vehicle from air suspension to coil spring suspension, if so desired. Although the ride will not be as smooth, the parts will be more durable and more reliable. 

Can I replace air suspension parts myself?

Replacing air suspension parts will take some work, but can be done by a do-it-yourselfer. Replacing air springs is fairly similar to replacing normal shocks or struts, and will not be substantially more difficult. As a safety precaution, you will want to ensure that the air compressor is off and depressurize the air suspension system before removing any air suspension parts. 

To replace air springs, you will have to disconnect the air lines that run to them, and unbolt them from the steering knuckle and the chassis. You can then install the new air springs, or replace them with coil springs from your conversion kit. You will want to replace air springs in pairs to ensure a level ride.

If you are converting to coil springs, you will need to deactivate the air compressor. Otherwise your dashboard suspension warning light will remain on. Coil conversion kits come with a set of instructions for deactivating the warning light. 

To replace the compressor, you’ll have to disconnect all the air lines, as well as the wiring harness that connect to it. Then, you can simply unbolt it and bolt on the new one. If the compressor is mounted underneath the frame, it will be easily accessed. If it is in the engine compartment you may have to remove nearby parts to access it.