What Problems Do Worn Suspension Bushings Cause?
A bushing permits movement between two parts without allowing them to contact each other by filling in the gap between them. When suspension bushings are worn, they don’t adequately fill the gap between the parts, which can lead to rattles and creaks over bumps, loose-feeling steering, uneven tire wear, poor wheel alignment and even broken components.
Related: When Should You Get a Wheel Alignment?
What Causes the Bushings to Wear?
In the case of a car’s suspension system, the bushings are usually slightly squishy in order to absorb road vibration while still allowing movement and are usually made of rubber, polyurethane (“poly” or “urethane” for short) or a similar material. Bushings can deteriorate due to the effects of friction, age and road salt, forming cracks or getting wallowed out. That allows more slop between parts than there should be, which results in noise over bumps or when turning or braking. The wear can also cause the parts to shift position, which can change wheel alignment — adversely affecting handling and tire wear — and lead to metal-on-metal contact that can cause the parts to break. The failure of suspension parts can lead to loss of vehicle control, as well.
How to Check for Suspension Bushing Wear
The best way to check for suspension bushing wear is to raise the vehicle off the ground by its chassis (not by its tires or suspension points), as you need to remove the car’s weight from the bushings so they can be inspected for any slop. This makes it handiest to do when performing an oil change or tire rotation, though you can do it yourself with a jack and jack stands. (Note that some checks may require you to be partially under the car, so make sure the car is solidly supported.) It’s usually recommended to raise both front or both rear wheels to perform the checks.
Once the weight is off the wheel, grab the tire at each side and try to move it in and out. Then, rock it side-to-side by pushing with one hand and pulling with the other, alternating back and forth. Repeat this with your hands at the top and bottom of the wheel. Any movement usually indicates worn suspension or steering components or worn wheel bearings, which should prompt further checking for the source. Bushings are commonly found in control arms, ball joints, stabilizer bars (also known as anti-sway bars), shock absorbers, struts and steering joints, as well as engine and transmission mounts.
What may warrant additional testing are the control-arm bushings. Control arms connect the wheel hub to the car’s chassis. You might need to put a crow bar between the control arm and the chassis and try to pry the two apart (ideally from several angles) to detect any excessive movement in the bushing. In some cases, the whole control arm needs to be replaced because the bushing can’t be replaced separately; this might also be advisable due to the added labor and expense in removing and replacing the bushing and because the control arms can rust out over time and get weak. Replacing control arms in pairs (both sides of the car) can also be a good idea, as if one is bad, the other probably isn’t far behind. It’s usually recommended to get a wheel alignment after replacing a control arm, too; this way, the alignment only has to be done once.
Rattles and clunks emanating from the front end can be more than just annoying. They can also signal mechanical problems that could become safety concerns and therefore should be checked sooner rather than later.
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