A car suspension system is designed to maximize friction between the road surface and the vehicle's tire, enhance passenger comfort and provide steering stability. Car suspensions have evolved a lot over the years, and modern vehicles have more advanced suspension systems than ever before. Despite all the improvements in suspension systems, though, problems still occur from time to time. Suspension components, including springs, shock absorbers (or struts on some vehicles), anti-roll bars, control arms and other parts, are like combat troops serving on the front lines: They take a pounding daily from potholed streets, railroad tracks, rain, snow, road salt, gravel, all manner of dirt and grime, and the occasional piece of scrap metal or other debris that drivers see too late to avoid.
Under those conditions, just about any part of a suspension system can be damaged or worn out from years of abuse. How can you tell if there are problems affecting your car's suspension? There's a number of symptoms and noises that should be your wakeup call to see a car doctor. Here are some common issues you're likely to encounter if your suspension is in need of repair:
- Poor wheel alignment: You might not think about your wheels when there may be a problem with your suspension, but you should. The wheels have to be pointed in the right direction (literally) and aligned for toe-in, camber and caster. If they aren’t, your steering won’t be centered when you’re going straight and tire wear will increase. Wheels get knocked out of alignment by potholes and curbs, but getting the wheels aligned won’t fix damaged springs, controls arms or other parts that affect alignment. When you buy new tires, it’s a good idea to have the alignment checked so suspension issues don’t shorten tread life.
- Shock absorbers: They really should be called “dampers,” and when they wear out, you should notice more bouncing after a bump and a whole lot of shaking going on over rough roads because they can’t keep the tires planted on the pavement. Shocks contain fluid that dampens the bouncing, and once they start to leak, suspension performance will deteriorate.
- Struts: If your vehicle's suspension has struts rather than shock absorbers, a knocking sound when going over bumps is a common sign of trouble. The strut assembly is a vital element of the suspension system in many cars, trucks and SUVs, so if you suspect a problem, see your mechanic right away. If this important part of your suspension fails, you may not be able to drive your car safely.
- Springs: Your springs are an important part of your car suspension. They are what hold the weight of the car, and as they wear they can sag or break. If your car is on level ground but one corner is lower than the others, that’s a sign of a damaged spring. You can measure the height of the corners to confirm your visual cue. You might also hear clunking noises over bumps, and the car may not corner with confidence because a damaged spring can’t control the weight it’s supporting.
- Ball joints: These are pivot points that attach the suspension to the wheels, and they absorb some of the shock from up-down movement and rotate as the steering angle changes. You’ll know they need replacing when you can hear them squeaking and creaking, especially when turning. You’ll know you waited too long if a ball joint breaks and suspension parts are dragging on the pavement. A mechanic can tell if they need replacing by the amount of wheel movement they can force by hand or, in some cases, by wear indicators on the ball joints.
- Control arms: These are hinges that hold the wheels to the frame and connect the steering to the wheels, so when you turn one, the other responds. Lower control arm bushings are important suspension components and they are more prone to wear out on front-wheel-drive cars than on rear-wheel-drive cars. Bushings are rubber and/or metal parts that help absorb shock, and when they wear, they can cause ride and handling problems and accelerate tire wear. So can a bent control arm. Signs of wear include clunks or rattles — because the wheels move back and forth in acceleration and braking — and loose, imprecise steering.
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