Q: What Can Cause a Vehicle's Suspension To Collapse

The suspension on your vehicle is comprised of many different components. Any of these components can fail at any time, but most suspension parts will fail slowly over time. If you have a sudden change in the way that your vehicle rides or how it sits, it is usually because something broke or failed completely. If your suspension has collapsed, then that can be caused by a few different things depending on what type of suspension you have.

If you vehicle is equipped with coil springs or leaf springs then you will have a broken spring if your suspension has collapsed. Coil springs are the most common type of spring on today’s vehicles. In order for the suspension to collapse on this type of vehicle, a spring would have broken and failed.

The most common type of suspension system that has a sudden drop in ride height are vehicles equipped with air suspension. Vehicles with air suspension are equipped with air springs. These air springs are put in the place on the coil or leaf springs.

Air springs provide two major benefits. They give the vehicle a better ride and they allow for a ride height adjustment. Vehicles with air suspension have a softer ride because you are essentially riding on air. The biggest benefit is the adjustable ride height. Vehicles with air suspension will have an air compressor that fills the air springs when needed to change the height.

If the vehicle needs to be lowered, it will have solenoid valves that open to release some air. Some vehicles will use this only on the rear allowing the vehicle to lift up when large amounts of weight are put in the rear of the vehicle. When that weight is taken out, the system will then let some air out. When a vehicle is equipped with air bags on all four corners of the vehicle, the ride height can be adjusted completely and not just in the rear. Some vehicles that are equipped with this system can lower so that people can easily get in and out of the car. Some vehicles will lower at higher speeds and some SUV’s can lift up higher when needed if they are driving off road.

If your vehicle is equipped with air suspension, the most common cause of the suspension collapsing is a bad air spring. When an air spring fails, it allows all of the air to leak that spring and will cause that corner of the vehicle to drop. It can also cause a loss of air in the system causing the entire vehicle to drop to the ground. Air springs are made of rubber, so over time, that rubber will rot out and eventually it will fail. Most of the time they will develop a small hole which allows the air to slowly bleed out. In other cases, the spring can pop completely and the vehicle will collapse instantly.

Other parts that can fail are the air lines, the air solenoids and the compressor itself. The vehicle will also be equipped with ride height sensors that can fail and send the wrong signal to the computer. If the computer detects that the vehicle it too high, then it will lower the vehicle until it reaches the desired height. If your suspension has collapsed, then it will need to be put on a hoist so that the suspension could be inspected for leaks. The easiest way is to fill the system with air and listen for leaks or use a solution of soap and water and spray it on the system components and look for bubbles indicating a leak. Once the system is repaired it can be pressurized.

Coming out to your car in the morning only to find it sitting much lower than it should be can be disappointing. It can be even more discouraging if the suspension does not pump up when the vehicle is started up. The biggest stress that comes from that experience is the cost. Repairing an air suspension system can be extremely expensive and not everyone can work on these systems. It is important to consult a certified mechanic, like one from YourMechanic, that knows these systems and can inspect your suspension and repair it for you. It is also important to keep in mind that many manufacturers have a specified towing procedures when the suspension collapses. Failure to follow these procedures can cause more damage, making the repair even more expensive.