Every car, truck, and SUV has a suspension, the collection of parts that holds the car off the ground, cushions passengers and cargo from bumps, and allows the vehicle to turn. The suspension includes wheels and tires, springs and shocks, various linkages and joints, and the steering system.
Like all parts of a car or truck, the suspension does wear out over time. And as it wears, the suspension may not perform as well as it originally did. For example, as joints in the steering linkages wear, the steering may become imprecise and the car may start to wander from side to side. Or as shocks wear, the car may start to bounce more than originally or may “nosedive” upon breaking.
But in addition to slowly wearing out, it’s possible for certain parts of the suspension to break completely. When this happens, is the vehicle safe to drive?
In general, a car with a broken suspension part will need to be repaired or replaced before it can be driven, but the specific consequences vary depending on what part is broken.
The most common breakages and their effects
Flat tire: Yes, tires are part of the suspension, and no, you can’t safely drive more than a short distance with a flat. Besides possibly destroying your wheel, driving with a flat tire may mean your car won’t be able to stop quickly, and the car may pull hard to one side or be very difficult to steer. Change the tire as soon as possible.
Broken wheel: Usually you won’t know a wheel is broken until it’s failed completely, leaving the car unable to move. But a wheel may be cracked, which can be diagnosed by a tire shop. Driving on a cracked wheel is theoretically possible but any crack can suddenly turn into a complete break, leading to catastrophic failure and possibly a crash. Repair or replace a cracked wheel immediately.
Failed or broken shock absorber: A car with one or more of its shock absorbers out of commission will bounce quite a bit and may roll, squat, or dive excessively. All of these actions can make the ride uncomfortable; more importantly, they render the vehicle harder to control, especially at high speed. Never drive a car with a broken shock absorber at highway speeds and avoid sudden turns or stops; in the long run, a broken shock will need to be replaced.
Broken spring: A car with a broken or collapsed spring can sometimes be driven, but the ride will be rough, bumps will tend to damage other parts of the car, and it will be very difficult to control the vehicle in an emergency. Also, note that if the car has collapsed far enough that the body is resting on one or more tires, all driving is unsafe because it’s only a matter of time before a tire comes apart due to the contact.
Broken strut: A strut is basically a shock absorber that also carries part of the vehicle’s weight. A broken strut therefore acts sort of like a combination of a broken shock and a collapsed spring, meaning that driving is uncomfortable, damaging to the rest of the car, and unsafe in an emergency; you’ll need to get it repaired as soon as possible.
Broken steering linkage: No. Just don’t do it. Whether the failure is in a joint such as a tie rod end or a ball joint, or one of the solid parts, a vehicle with a broken steering linkage part cannot be relied on to turn when you want it to.
Broken sway bar: A sway bar (also known as an anti-sway bar) is one of the few suspension failures that can safely be left alone for a while. Because the sway bar comes into play only when the car is rolling to the side during cornering, a broken one hurts the vehicle’s cornering ability by allowing it to roll more, but it’s not inherently unsafe to drive as long as the wheels remain planted on the ground. Unfortunately, a car with a broken sway bar may be less capable of sudden turns, so with its emergency maneuvering compromised you’ll want to drive more slowly than usual and eventually to get the broken bar replaced.
Failed power steering: Whether hydraulic (fluid-based) or electric, any power steering system can fail. Such a failure often renders the vehicle very difficult — but possible — to steer. Because of the high effort you’ll want to get the problem repaired as soon as you can, but it’s still possible to drive; you’ll want to go slowly and you should expect turning the wheel to be quite difficult, particularly at parking lot speeds when it may take all your strength to turn the wheel at all.
Anything else: Suspensions are composed of too many different parts to list, but almost every one is necessary for safe driving; any broken suspension part will have some negative effect on a car’s handling, steering, or braking, and a car with a broken suspension piece not listed above should not be driven lest you endanger yourself and others.