Suspension air bags are common on many luxury or larger sized cars, trucks, and SUVs and are designed to provide extra ride comfort and vehicle stability when carrying heavier loads. Suspension on any vehicle works best when all of the individual components work in conjunction in the way they were designed. From time to time, one or many of these individual parts will wear out or break entirely, causing additional parts to fail and potentially creating an unsafe driving situation. One of the most common parts that fail is the suspension air bag.
The suspension air bag is typically in the rear of a vehicle and on rear-wheel drive cars, trucks and SUV's. It works by receiving air from the suspension compressor that is also located near the rear of the vehicle. There are several individual parts of the air ride suspension that can cause similar symptoms as we will indicate below, which is why it's very important to have a professional ASE certified mechanic inspect your vehicle if you notice the following symptoms.
1. Rear of the car feels loose or spongy
One of the more common myths about air suspension is that it only activates when heavy loads are introduced. On the contrary, the suspension air bag runs constantly; unless turned off manually through a switch that is commonly located in the trunk of the vehicle. However, a suspension air bag that is active is a critical part of the drivability, especially on the rear end. If it's leaking or is not receiving proper air from the compressor, the rear suspension can feel loose or spongy when driving the car. This symptom is commonly felt while driving slower on a curvy road, driving over a speed bump or on bridges with multiple seams in the concrete.
If you have a vehicle that has suspension air bags, and you notice that the rear end of the vehicle just doesn’t feel right while driving, contact a local ASE certified mechanic to test drive, diagnose and repair any damaged parts.
2. Air compressor runs frequently
Anytime a pneumatic device can't keep air contained, it's usually caused by a small leak. When this happens, the automatic air compressor that can sense the air pressure inside of the suspension air bag will frequently activate in order to maintain the right air pressure. Since the air bag compressor is located under the rear of the car, and inside the body panels in many cases, it is insulated and can be hard to hear. However, if you hear it running after you turn off the ignition, this is a warning sign that a leak in the suspension air bag exists.
3. Bouncy or rough ride
The primary job of suspension air bags is to improve ride comfort, which is why they are commonly found on Cadillac, Lincoln and other premium full sized car brands. While no car is completely smooth, it should not be bouncing or produce a rough ride frequently. If you have a car with a suspension air bag, you'll notice if the ride is dramatically different. When this occurs, contact your local ASE certified mechanic so they can inspect the suspension air bag and supporting suspension components and replace the suspension air bag if needed.
4. Vehicle sags on one side
There are two suspension air bags in most US cars and trucks; each of them located near each rear tire. Due to the fact that the suspension air bags are helping to take off some of the weight and keep the suspension level, if they are leaking the vehicle may end up sagging. This can be more noticeable in higher end cars that automatically adjust the suspension air bags to maintain proper vehicle height and when they are not carrying additional weight in the trunk. A problem with the air ride suspension can also be seen visually if the ride height of the vehicle seems much lower in the rear of the vehicle.
The suspension air bag can last the life of a vehicle or have mechanical problems the day the vehicle is driven off the factory floor. It's one of those parts that really can't be predicted when it will fail, spring leak or have other damage done that requires service. However, if you notice any of the above common symptoms, don't wait to have the dealer check it out during your oil change. Contact a dependable ASE certified mechanic as soon as possible so they may test drive, diagnose and repair what is broken, before it causes additional problems.