Steering Wheel Shakes When Braking, But Why?

Rotors are discs that your brake pads clamp down on in order to stop your car. In other words, they're pretty important. Why they may cause the steering wheel to shake when braking requires a quick review of how brake rotors work.

Brake rotors are usually made of metal and function at a specific width, depending on the make and model of your vehicle. When you apply the brakes, the rotors are exposed to intense heat that must be dissipated evenly across its surface for a smooth stop.

However, brake rotors tend to wear down over time. As this happens, the metal may become thinned out or warped in certain spots. When the brake pads grip the rotor at high speeds, these imperfections cause a rumbling in the brake pedal that's then transmitted to the steering wheel.

The good news is that there are some simple solutions for fixing the problem, which we'll explore in the next section.

The first step in finding a solution for a steering wheel that vibrates during braking is to determine the cause of the shaking. As we mentioned, this is almost always caused by a problem with the rotors. Other causes of a vibrating steering system would generally cause shaking all the time, not just when braking. With that in mind, we'll focus this section on the most common rotor problems and their solutions.

Uneven Rotor Tightening

One possible cause of vibrations in a car's wheel is an uneven tightening of the rotors. In that case, you should get yourself to a mechanic who knows how to tighten lug nuts in a star pattern . This is an elementary concept that any mechanic worth his or her salt should know.

Most will also have a torque wrench to measure the tightness of the seal. Keep in mind that every car has its own standard torque specifications, which can be found in the owner's manual, or a mechanic's database.

Warped Brake Rotors

More often, a steering wheel that shakes when braking is caused by warped brake rotors, which your mechanic may be able to diagnose with a simple test — that is, by spinning the rotors by hand to feel for imperfections.

A rotor in good working order should move freely and make a complete revolution without any bumps or signs of resistance areas. If you or your mechanic does notice these issues, you've probably got yourself a rotor problem.

For a more definitive diagnosis, your mechanic will need to remove the rotors and measure them with a micrometer. Rough spots or areas that are more worn than others may be re-machined with a lathe. This is called "turning" the rotors, and it shaves off a very thin layer of metal until the surface is smooth again. However, this tactic may not be your best bet. Turning can correct light warpage but won't do much good if the rotor is worn outside of the manufacturer's specs.

Nowadays full replacement is the more common operation. If your car has received a diagnosis of bad rotors, you might be wondering how urgent a problem this is. It depends on a few factors, which we'll address in the next section.

If your steering wheel shakes when you apply the brakes, chances are you're going to need a mechanic fairly soon. Exactly how soon depends on a few factors, including the cause of the shakes. For example, you may be able to ignore the problem for a while — months or perhaps even years — if it's caused by improperly tightened rotors. The same is not true if the problem is caused by loose lug nuts. In that case, you'd be lucky to make it around the block.

As we mentioned in previous sections, a quivering steering wheel is caused by warped rotors in most cases. It's certainly possible to ignore this problem, but do so at your peril. Chronic vibrations can cause brake calipers, bolts, brake pads, ABS sensors, and other components of the braking system to loosen or wear out.

Ignoring steering wheel vibrations will quickly drive up the cost of what was originally a relatively inexpensive repair. The cost of replacing rotors is about $300-$400 with parts and labor.

Larger and high-performance brakes will tend to be more expensive. Rotors and pads are commonly replaced together, running closer to $1,000 with combined parts and labor. If long-term neglect causes surrounding components to fail, then the cost can be several times that much.

Another reason not to ignore your warped rotors is that the shaking they cause during braking may result in loss of stability. Driving is already one of the most dangerous things we do each day, so there's no reason to increase your odds of a crash. Besides, very few of us are able to avoid looking ridiculous when clutching a wobbly wheel.

You should also get the most longevity out of your braking system by having brake pads and rotors checked during regular maintenance. Like tire treads, brake pads wear down over time, and have a range of depths in which they're meant to function correctly. When they're completely worn down, they'll hit pieces of metal at the bottom called wear indicators. These cause a loud squeal when the brakes are applied and they make contact with the rotor, indicating that the pads should be replaced as soon as possible.

Continuing to drive around on worn brake pads is a sure-fire way to damage your rotors and increase your repair bill. Brakes can also overheat and warp after repeated hard stops, but this is less likely to happen under normal driving conditions.

In short, driving for a little while on warped brake rotors is probably OK, but don't ignore the problem for too long. Doing so is likely to lead to significant damage to your brake system and more expensive repairs in the long run. All things considered, it's best to have the problem fixed as soon as possible.

So, before you hit the road with your quivering car, be sure to ask a mechanic you trust to take a look at your rotors. Chances are you can solve the problem quickly without breaking the bank.