All you need to Know about Air Suspension System

Author: Mike Johns Imports

The air suspension system has more advantages over the conventional suspension systems. It offers instant tuning, better handling in variable situations and different load capacities. An air suspension supports the vehicle on the axles with an arrangement of air bags instead of some type of steel spring, leaf, coil or some type of torsion spring arrangement.

The air suspension system constitutes of the on board air compressor which is powered by the electrical system of the car and enables inflammation of the air bag. The compressor induces high- pressure air to each spring by the help of pipes made of either polyurethane or stainless steel.

The air bags are sometimes referred to as air springs or bellows. Suspensions that have steel or torsion springs that are supplemented by the use of air bags are not considered air suspensions. There are combination systems that have both air and steel springs. Usually the air suspension components are used on the rear of the vehicle. Depending on the situation, this type of air suspension will probably have to be dealt with for leveling purposes.

An air suspension has three basic components:

  • Air compressor
  • Air bags
  • Height control valves

Air compressor

The engine air compressor supplies air for every piece of air equipment on the vehicle. The maximum pressure supplied by the compressor varies. The air supply is maintained through an arrangement of air tanks. Air tank arrangement is one thing that varies greatly between different air systems.

Air system air lines and fitting also vary in size, color, and ratings. Although there are suggested standards for airline colors when dealing with specific chassis manufacturers, there does not seem to be any governing regulations covering airline colors. Air lines and fittings do have to be rated for their particular use.

Air bags

The air bags are simply a rubber bladder that holds air. Air bags are also referred to as air springs or bellows. The air bags are located between the frame of the vehicle and the vehicle axles. Air bags are rated for weight and pressure capacities.

Air bag placement and arrangements vary amongst chassis manufacturers. At the very least, there will be one air bag for each side of each axle in the vehicle. Some manufacturers use two air bags for each side of the drive axle and some use two air bags for each side of the drive and front axles. Space between air bags for side to side placement also varies.

Height control valves

The height control valves are kind of the brains of the system. They dictate how much air is in the air bags. This dictates the height the vehicle sits at, thus called as height control valve. Most of them are mechanical valves but electronic HCVs are available. The HCV is mounted to the frame of the vehicle. An L shaped linkage attaches the HCV to the axle. As the axle moves up and down in relationship to the frame, the linkage moves the valve or electronic mechanism

The HCV also has an exhaust port. When the connecting linkage moves up, the HCV connects the air supply to the air bags, inflating the bags. When the connecting linkage moves down, the HCV connects the air bags to the exhaust port, deflating the bags and thus controls the height of the vehicle.

Common issues in air suspension

One of the most common air suspension problems is a leaking air spring which is due to the deterioration of the rubber components, creating holes and tears and causing an air leak. Due to bad air suspension, you may experience a bumpier ride because a damaged air spring can’t absorb the shock from bumps in the road. The air compressor keeps constantly running as its work is to keep the bags and springs properly inflated and when there’s a leak, the compressor does not stop.

A faulty compressor is also a common air suspension problem as the compressor mainly works to keep the air springs inflated. Oftentimes, a compressor malfunction because it’s overworked, meaning that it runs more often than usual which wears it out and causes the part to fail faster. One way to determine a faulty air compressor is to check the vehicle height and if it’s riding lower than usual, the compressor may not be working properly.

The compressed air within an air suspension system contains moisture that can accumulate and lead to severe damage. This issue is caused by a malfunctioning air dryer assembly, a part designed to remove moisture from the compressed air. Excessive moisture in the compressed air within the suspension system could result in rust and corrosion.