How to Tell If Brake Rotors Are Bad [Sign And Solutions]

A brake rotor is a key component of a car’s brake system. It works in unison with the brake pads and the caliper to eliminate the motion of a running wheel.

When you press on the brake pedal, it enables the caliper to apply pressure to the brake pads, which in turn squeeze on the rotors and ultimately brings your car to a stop.

Now, disc brake rotors are not made to last forever. Over time, they start to get warped or worn and need repair or replacement. But how to tell if brake rotors are bad? What are the signs that bad rotors generally produce? Let’s find out.

How Do They Get Bad?

As mentioned earlier, the function of disc rotors is to stop a running wheel. How do they do that? Well, when you pull the brake, the rotors engage with the brake pads applying friction while spinning with the wheel and breaking the motion of it.

Now, as we all know, friction generates heat. With a long time of use and also with frequent brakes at high speed, excessive heat causes damage to the rotors. Over time, the rotors deteriorate and eventually reach a point when you need to replace them. 

How to Tell If Brake Rotors Are Bad

How to Know If They Are Bad?

With constant use, your brake rotors get wears and tears and fail to do their job properly. That’s when it becomes your job to inspect, identify, and take necessary actions.

Read below to learn about the most common signs your car shows when the brake rotors go haywire.

1. Noisy Brakes

The very first sign you might get from bad rotors is that it may make noise when you pump on the brake. This is one of the most common signs encountered by car owners. You may hear a squeaking or squealing sound – like the sound of nails on the chalkboard, or even worse.

Generally, if the rotor is warped, which means that the surface is not flat enough, it will create a high-pitch squeaking sound. On the other hand, worn rotors are more likely to project a rather scraping sound.

However, the squealing sound might be produced from worn brake pads, too, so it’s better to check out which one is the culprit. If you hear a sound that’s more of grinding, you are in danger because the rotors are really in a very bad condition.

So, when you hear such kind of bad sounds, do a check on your brake system.

2. Vibration from Brakes

This is also another common occurring that bad rotors project. It so happens that when you press on the brake pedal, you suddenly feel excessive pulsation or vibration. The vibration could be felt either at the pedal or from your steering wheel. This problem occurs when a rotor is badly warped or worn.

You could also be hearing a grinding sound along with the vibration. Take them as a serious sign that the brake pedal is possibly failing to make contact with rotors. So, when you feel it, don’t wait to perform an inspection right away.

3. Grooves Or Score Marks on the Rotor

Exactly! If you see grooves or score marks on your rotor, then it’s not a good sign either. With frequent contact with the brake pads, rotors tend to develop these kinds of marks. 

And these marks generally reduce the capacity of rotors to slow down the wheel. A healthy rotor should have a smooth surface, free from any visibly significant marks or grooves.

Also, if your rotors have rust all over it, it is another issue to pay attention to. Rusted rotors won’t be able to operate smoothly. You might hear squeaky sounds, and your brakes might feel sticky when the rotors are rusted. So, whenever you see a lot of rust over the surface, you should not wait long and do something about it.

4. Rotor’s Thickness

A rotor should have a minimum thickness to run properly. But rotors are built to have the thickness level to be decreased with prolonged use. If the thickness is below the manufacturer’s specifications, you should replace the rotor.

What you can do is open the wheels and detach all the components of the brake system. Then measure the thickness of the rotor with a micrometer and get to know whether it is viable anymore or not.

5. Increased Stopping Distances

So, let’s say you are driving on a highway at a somewhat good speed. Then suddenly you pull the brake, but the car doesn’t stop right away. It goes a bit further and slowly ceases to move. This is a dangerous scenario, right? Because it risks an accident if in an emergency scenario.

Such a thing can be caused by bad rotors, and if you ever inspect something like this, don’t wait to have a quick look down at all the parts.

The Solution

Rotors are designed to be worn out over time, and after a long while of use, you should expect it to go out of order. 

However, what you can do is regularly perform inspections, like once every six months, to ensure that your car and its brake system is working properly. If you feel something to be out of ordinary, you can always head to a professional or repair shop.

You should do all of these to avoid the risk of severe casualties in the future. It is always recommended to have the bad rotor replaced. The replacement of rotors and brake pads should cost somewhere between $300 and $700, depending on the type of your car and its brake components.

Watch How to Tell If Brake Rotors Are Bad and Needs New Rotors-What To Look For


A disc brake rotor is one of the major factors that determine the performance of your car and its overall safety. Bad rotors will make it hard for you to handle your car, not to mention the risks it yields.

Like all other parts, rotors should also be maintained and replaced when needed. Also, remember that it’s always “safety first.” By now, you already know how to tell if brake rotors are bad, so don’t wait to act.


John D. Archer is a mechanical engineer and writer based on the area of automotive accessories at, A resident expert and professional, John is passionate about all things automotive and loves to share his knowledge. He has good experience in all kind of automotive accessories. He has worked as a chief mechanical engineer in some reputed automotive garage firm.

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