Home Diagnosis and TroubleshootingBraking System Bad Rotors – What Are The Symptoms?

Bad Rotors – What Are The Symptoms?

by Jordan Harris
Bad Rotors

Are you hearing some weird noises when you apply your foot on the brake and you think you’re experiencing bad rotors symptoms? If this is the situation you are in, then you are at the right place because there will be a lot to cover on this topic.

Having your brakes in check is key if you want to avoid some dangerous situations. Your brakes should be always in top shape if you want to avoid getting yourself injured and also avoid damaging your vehicle or hurting other people.

As you know cars with bad brakes often don’t stop as it was intended for that car to stop. So, if you are noticing some weird issues happen and your car does not stop right, then it is the right time for you to look for a solution for this problem. Luckily for you, we are here to help you by listing all the possible signs of bad rotors that you can experience and also learning how to diagnose this specific issue.

It is important for yourself to familiarize yourself and that’s why we will start from the basics of what are brake rotors and what is their role. Then we will learn how the brake system works and then we will focus on the signs of bad rotors. Later we are going to learn the possible ways to solve this problem and also the cost to solve this problem since nothing is free in this world. So, if you want to learn more, please follow along till the end.

What Are Brake Rotors?

Before we delve into the important symptoms of bad rotors. Let’s first start from the basics. This will be extra useful for the ones who are not familiar with what rotors are and how they look. If you feel that you are more advanced, you can skip to the symptoms. If not, follow along.

Brake rotors as their name implies are large metal discs that are installed usually on the front wheels. Some cars also have them on the rear. The front rotors are usually larger and the rear ones are smaller since there is no need for the rear to have the same brake force as the front.

Nevertheless, rotors were invented in the ’50s and by the ’80s became the standard equipment in most cars. They replaced the old type of brakes also known as drum brakes. These drum brakes perform quite poorly compared to rotors. Especially if they are pushed hard. They tend to overheat quite a lot in comparison to rotors.

Bad Rotors

Today drums are still used as rear brakes. You will often notice them mounted on the rear wheels. If there is not a disc that is shining behind the wheel. Then you are probably having drum brakes on that tire.

These rotors have become an irreplaceable car component because they deliver an incredible performance. Not to forget that they last for quite a bit more than drums. The usual service interval for discs is 60,000 miles. Meaning that these brakes will last you for a lot of time. Unlike the pads in the drums that have to be replaced every 20,000 miles or less.

And on top of all, they are also affordable. But what are the symptoms of bad rotors? We will get there, let’s first learn why they are important.

Why Rotors Are Important?

Now, let’s separate a small chapter on the importance of rotors. This will be quite handy for you to know why they are so essential and why it is the best immediately to replace worn and bad rotors.

The important thing that rotors deliver is the brake distance. The bigger and better the rotor is the better the car will come to a stop.

That’s why you see on race cars brakes with six or even ten pistons. These discs are massive. But they do the job well when it comes to stopping the car on the race track. So, if you want to race your vehicle on your local course. The best thing would be to upgrade the factory discs with aftermarket ones that deliver a much better performance than the stock ones.

We mentioned pistons. But what are pistons in general? The pistons are the ones that make your car stop. They apply the hydraulic pressure to the pads and then the pads press the rotors. And more on that topic we are going to learn in the following chapters when we are going to discuss how the braking system works and then we will learn the types of rotors that are out there. Later, we will learn how to recognize bad rotors. So, let’s move on.

How The Braking System Works?

Before we talk about bad rotor symptoms, let’s learn how the braking system works. It is important to know that this system works with the help of a vacuum.

When you apply your food on the brake, you create a vacuum and this vacuum is built up into the master cylinder. The master cylinder is connected with the brake pedal directly. Then from the master cylinder, there are brake lines that go to that specific wheel where they take the hydraulic fluid.

So, what is the role in the vacuum here? The role in the vacuum is to open and close the pistons. When you press the brakes, the fluid moves to the lines and opens the pistons, and applies pressure on the pads and rotors. But the key here is that this fluid has to return and the pistons have to close again so the wheel doesn’t end up stuck in the process.

If there is no vacuum, the pistons will open and the rotors will simply lock up. Here the vacuum plays a big role as we mentioned to bring the pistons on the rotor back to their original position.

So, for this system to work, you need to have a brake fluid also known as DOT. There are a few of these fluids out there like the DOT 3, DOT 4, DOT5, and DOT 5.1. You always got to have the specific fluid for your application because these fluids do not mix interchangeably. Meaning that once you use one of them, you need to flush the system to change the fluid to another spec.

So, what are the symptoms of bad rotors? We will get there in a bit, let’s first cover the types of rotors.

Types Of Brake Rotors

Now before we talk about the symptoms of bad rotors. Let’s first discuss the types of brake rotors that are out there. This will be quite handy for you if you want to replace your stock rotors with something more potent that will deliver a better stopping power. So, what are the types of rotors out there? Let’s elaborate.

The first type of rotors are the base ones. These rotors are smooth. Meaning that they do not offer many features except for stopping the car. What is bad with these rotors is that they often know to overheat and warp if they are used on the race track or if you love to drive your car hard.

The second type are the slotted rotors. These rotors are slotted from the factory and deliver better performance while braking. These slots are slightly helping the brake performance of the vehicle and delivering a better braking experience.

The third type of rotor is the drilled rotor. These rotors deliver excellent cooling abilities since they have holes in them. This greatly aids the cooling and these rotors are especially recommended for driving the car hard. Meaning that they should be used on the track.

But let me tell you that there is also another option and that is to get drilled plus slotted rotors in one package. You get the brake performance along with the excellent cooling ability. And frankly, you cannot beat that. Unless you go to the extreme.

And the extreme is carbon-ceramic rotors. These discs are only intended for track use on the street they are noisy. And when we are talking about the noises, what about the symptoms of bad rotors? Well, that we are going to cover next.

Symptoms Of Bad Rotors

Now we reached the important section of this article and that are the symptoms of bad rotors. How you as an owner will be able to tell if your brake discs are junk and have to be replaced?

Bad Rotors

What are the key signs or symptoms that are connected with this problem of bad rotors? Knowing them will save your life, literally. Since the braking system plays such an important role for you as an owner. That’s why in the following chapters we are going to elaborate on them in-depth and deliver you the most accurate result that we can get. Enjoy!

1. Squealing Sound When You Press The Brakes

The first and most common symptom associated with bad brakes is the squealing sound when you apply the brakes.

This symptom is most experienced in bumper-to-bumper traffic. The brakes are at the end of their lifetime and they heat up more than expected. Attributing to this unpleasant noise to develop and annoy you.

When you hear a squealing sound when you stop, you just know that there is a problem with the brakes.

But it doesn’t have to mean that there are bad rotors. Could be only the pads that are worn out and have to be replaced. Some pads are really low quality and wear like crazy. So, if you did a brake job, you should check the pads first.

It is important to act quickly whenever you notice this symptom. If you leave it like this, there will be some permanent scarring to the rotors and they will have to be resurfaced. Now let’s move on to the next symptom.

2. Vibrations When You Press The Brakes Can Mean Bad Rotors

The second symptom of bad rotors that we are going to cover are the vibrations that are created from the rotors when you apply your foot on the brakes.

This symptom is mostly happening whenever there are warped rotors. But what does this mean? This means that the rotors overheated at some point and they are now warped. Meaning the surface is not evenly smooth and there is unevenness.

In some instances, if the rotors are extremely worn vibrations also happen. But not that often. This symptom is most associated with warped rotors.

Whenever you notice this symptom, the best thing is to check the condition of the rotor and the wear marks. This will tell you a lot about the overall health of the rotor and its condition. Sometimes warped rotors are difficult to notice and you will have to remove them to see if the rotor is really warped.

But the simplest thing is to replace them altogether with the brake pads and call it a day. This way you will be sure that you don’t have bad rotors anymore.

3. The Vehicle Doesn’t Like To Stop Well Because Of Bad Rotors

Another in the list of bad rotor symptoms is when the vehicle doesn’t brake well. This symptom will be noted when the brakes are simply done and worn out.

The ABS system will have to engage more often than usual. Even for some really minor braking. The car will not love when the discs are bad. Especially if they are warped and not worn.

Warped rotors are a real pain and they could greatly limit the braking distance of your car and make your car extremely unreliable when braking.

The brake distance could increase to 10 or 20 ft than the factory spec. This will require adjusting your driving based on the input you get from the brakes. For example, if you brake as you did before this happened, it is highly likely that you are going to hit someone. So, it is better to be safe than sorry. If the car doesn’t like to brake well. The best thing would be to do a brake job as soon as possible. Bad rotors are not the thing you want. Now, let’s move on to the next.

4. Visible Cracking On the Rotor

Visible cracking of the disc is another symptom of bad rotors. As you know, rotors go through countless cycles of cooling down and heating up. This is bad for the metal that the brake disc is built of.

With every cycle, the metal is getting more and more prone to cracking. On regular rotors, cracking is rare. Unless there is extreme overheating. This problem is most notorious on high-performance rotors that are drilled.

The drilled rotors are more prone to cracking since the structure of the disc is weakened by the holes that are in it. These holes might improve the cooling but are definitely not going to make the rotor last for a long time.

High-performance discs are often disposable items that are often running hard and when they warp or get cracked are being replaced. So, if you notice some cracking to develop. It means that you have bad rotors. Replacing them is the only solution for you, unfortunately. How much it is going to cost you we are going to cover in a bit.

5. A Big Lip At The Side Of The Rotor

And the last symptom of bad rotors that we are going to cover is the lip on the edge of the rotor. This edge is by design used by some automakers to indicate that the rotor has to be replaced.

If you check the condition of the rotor and the edge is really big more than a few millimeters. This is an indication that the rotor is worn and has to be replaced.

This is a simple trick to see the condition of the rotors if you are purchasing a used car and want to see what has to be done to it in order to get it completely sorted.

And also it can indicate that you have bad rotors in your car. After this is up to you whether you will resurface them and get all of the juice out of them or replace them with new ones. And in the following chapter, we are going to discuss precisely where we will learn what is better, to resurface or to replace the rotor completely.

What Is Best? To Replace Or Resurface Bad Rotors?

We learned the bad rotor symptoms, now let’s see what is the best thing you can do, replace them or resurface them? Let’s discuss.

In the past, rotors were really expensive things. But as technology has evolved, they have become cheaper and cheaper.

Back in the day, everyone wanted to resurface them and people still do the procedure. Not that it is bad. It is a good thing, you will milk everything out of them.

By replacing them you throw half good rotors. So, if they went through one set of pads, maybe the best thing is to resurface them and bring them back to factory spec.

This is not ideal for warped rotors though. Why is this the case? Well, this is the case because these discs are well gone and cannot be straight again. Even if you resurface them, a big amount of the material will be removed. Meaning that this material in some places will wear much quicker than the rest of the disc.

To sum things up, don’t resurface warped rotors. These need to be replaced with new ones and you will never have a problem in the future.

If else, you can resurface them and some places are doing this on the cheap. Much cheaper than getting new rotors for your car. If they have a lot of life, it is a no-brainer to throw them in the trash and recycle.

Still, if you are running a high-performance vehicle. Maybe it is the best thing to replace them with new ones. That’s why it’s up to you. But what is the price to replace bad rotors? That we are going to cover next.

Cost To Replace Bad Rotors

So what is the cost to replace bad rotors? Luckily for you, doing a brake job is not that expensive after all. These parts are fairly cheap and affordable for everyone out there.

The cheapest rotors will probably cost you about $75 per piece. So, if you are doing both of the front wheels, you will have to pay about $150 for both of them. Not a lot of money. The rear rotors are cheaper and can be purchased for $50 per side. A total of $100.

So, the fronts plus the rears, that is about $250 for the parts alone. But remember that you will also need to get brake pads.

Bad Rotors

Brake pads will also cost you about $25 per wheel. With a $100 for all 4 wheels. A really affordable cost.

So, to sum things up, the discs and pads will cost you about $350 in total on average. But what about the labor? The labor is relatively expensive I must admit.

The cost of the labor varies between $150 to $300 per single axle. So, if you do both of the axles. You can expect to pay from $300 to $600. Not the ideal thing but labor costs as you know.

You can also do a DIY brake job if you feel capable to do it. This way you will save a lot of money in the process. If you are a car guy then this is the way to go!

Car Brake Rotors: 4 Signs You Need to Know – Facts

  1. Noisy brakes are a common sign of bad brake rotors; if they’re warped or severely worn, they may produce squealing or squeaking sounds.
  2. Excessive vibration or pulsation coming from the brakes is another symptom of bad brake rotors; warped or excessively worn rotors may cause vibrations that can be felt in the pedal and sometimes through the vehicle’s steering wheel or chassis.
  3. Visual scoring or grooves on the face of the rotor are another sign of bad or failing rotors; repeated contact with the brake pads can develop these marks over time, which can lower the overall safety of the vehicle.
  4. Scoring and grooves in a rotor can impede its capacity to slow the vehicle, which can result in extended stopping distances and even make it feel like the car will not stop at all. This can be highly dangerous, especially in emergency situations.
  5. Disc brake rotors work together with the brake pads and calipers to slow the vehicle and are bolted directly to the wheel hub, so they spin in direct relation to wheel speed.
  6. Rotors wear out over time and will eventually need to be replaced, as they work to slow the vehicle by using friction from direct contact with the brake pads.
  7. When rotors have a problem, they usually produce any of the four symptoms mentioned above that alert the driver they require attention.
  8. Brake pads can also produce noise, so it’s important to have a professional technician inspect the vehicle to determine if the noise is caused by worn brake rotors or brake pads.
  9. If you suspect your rotors may be worn or damaged, have the vehicle inspected by a professional technician to determine if your car needs a brake rotor/disc replacement.
  10. Disc brake rotors are a critical part of the braking system, and as a result, are important to the overall safety and handling characteristics of the vehicle.

Conclusion To Bad Rotors

In this article, we learned all about bad rotors. First, we learned what these rotors are and why they are of such importance for you as an owner. Then we covered the types. There are smooth, slotted, drilled, ceramic. Many different types. If you are running just a regular car, the basic ones will do the trick just right.

Then we learned the symptoms of worn discs and we covered all the signs that mean that your discs need replacing. These are the squealing sound, vibrations, visible wear. There are many of them.

Lastly, we covered the cost involved in this job. The parts alone are cheap. What is expensive is the labor that sometimes even cost double or triple the money of the parts.

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1 comment

Zachary Tomlinson 06/05/2023 - 5:20 AM

Thanks for suggesting having your vehicle maintained by a professional since this can help you ensure that its brakes and other components are working. My brother is interested in owning a used semi-truck for personal use. I will talk to him about finding a local repair expert that can help him out someday.


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