Air bag suspension systems are a common feature found on many modern luxury vehicles and SUVs. They work by using compressed air to pressurize inflatable shocks to suspend and support the vehicle. Because they operate using compressed air, excessive moisture accumulation is one of the biggest issues that must be addressed for a properly functioning system. It is the job of the air suspension dryer assembly to keep the compressed air in the system as dry and moisture-free as possible. Moisture is a problem because it can react with the metal components of the system and cause rust and corrosion to form on the internals of the system. Internal rust and corrosion on the system’s components can quickly develop into bigger problems due to the high stress and high pressure nature of air suspension system.
The air suspension dryer assembly is what protects the system from moisture. If the dryer fails or has a problem, it will usually present itself as a symptom or problem with the entire system or a specific component (usually the compressor) and should be serviced. For this reason, most of the symptoms associated with a problem with the dryer assembly are similar to those of a problem with the compressor.
1. Suspension sagging
One of the most common symptoms of a problem with the air suspension dryer assembly is a sagging suspension. When the dryer fails, moisture can accumulate in the air suspension system and interfere with its leveling capabilities, which may cause one or more of the vehicle’s corners to sag. In more serious cases, components may even become damaged by the corrosion and additional stress caused by moisture build up from a failed or leaky dryer.
2. Bouncy suspension
Another symptom of a possible problem with the dryer assembly is a bouncy suspension. If excessive moisture builds up anywhere in the system, or a leak occurs from corrosion, then the ability of the system to hold and maintain pressure may be hindered. This may result in a bouncy suspension that leans excessively at takeoff, when turning, or during heavy braking.
3. Compressor does not come on
Another symptom of a problem with the air suspension dryer is a compressor that fails to come on. If the air compressor becomes damaged due to excessive moisture buildup, it may cease to function completely. As the compressor is what pressurizes the entire air suspension system, if it fails due to any sort of moisture-related issue possibly stemming from a problem with the dryer, it will cause problems for the entire system.
Because the air suspension dryer assembly is what protects the entire air suspension system from moisture, it is one of the system’s most important components. For this reason, it is important to make sure that the dryer is always in good functioning order. If you are experiencing any of the symptoms above you are likely experiencing a problem with the suspension. In you need help with this, a technician from YourMechanic can diagnose your suspension and replace your air suspension dryer if necessary.
This article originally appeared on YourMechanic.com as Symptoms of a Bad or Failing Air Suspension Dryer Assembly and was authored by Ed Ruelas.