Common Symptoms of a Bad Brake Disc

Written by

Mia Bevacqua, ASE Certified Master Automobile Technician

Automotive Subject Matter Expert at CarParts.com

Updated on May 15th, 2024

Reading Time: 5 minutes
Summary
  • Disc brake systems rely on the friction between disc-shaped brake rotors and brake pads for stopping power. All modern cars have front disc brakes and many have disc brakes on all four wheels.
  • The common symptoms of a bad brake disc include abnormal noises, reduced stopping ability, visible imperfections, and thinned-out brake discs.
  • If you suspect that you have bad brake rotors, diagnose and repair the problem right away.

Here’s a novel concept: Disc brake systems contain brake discs, which are also referred to as rotors. Like brake pads, rotors are considered wear items that require periodic replacement.

I change my car’s brake rotors every time I swap out the brake pads. That way, the new pads and new rotors mesh together in harmony from the beginning.

Last month, while rebuilding the front end of my Astro Van, I found the front brake pads to be extremely worn. So, I ordered a new set of pads and a pair of rotors online and—voila!—they appeared on my porch within a couple of days.

Even though repair shops often resurface rotors instead of replacing them, modern rotors are affordable enough that I opt for a new set every time. Who wants to stand around hunched over a brake lathe anyway?

Some people argue that you don’t always have to service the pads and rotors together. But I’ve done it that way my whole life. To me, spending a little extra money on new rotors is worth it because, well, your brakes are extremely important.

Consider changing the brake rotors every time you swap out the brake pads. That way, the new pads and new rotors mesh together in harmony from the beginning.

You May Have Faulty Brake Discs If…

Brake rotors are simple components with a rather limited list of common symptoms. Some signs your rotors may be worn include:

  • Vibration or Pulsation: Worn brake rotors often cause a pulsation or vibration while braking. The sensation is felt in either the steering wheel or brake pedal.

Why does this happen? The rotors become worn unevenly over time. As a result, the pads bounce up and down over the high and low spots of the rotor surface.

  • Abnormal Noise: Rotors with uneven surface wear can make a chattering noise when contacting the pads. You may also hear a clunking noise when the brakes are applied.
  • Wear Beyond the Manufacturer’s Recommendation: Your brake rotors and pads mesh each time you hit the brake pedal. Because of this, both wear down over time. That’s why professionals measure rotors for thickness whenever a brake check is performed.

If the rotors are worn beyond the manufacturer-recommended minimum thickness, they must be replaced. This specification may be stamped into the front of the brake rotor, or it can be found in your vehicle’s factory repair information.

  • Reduced Stopping Ability: An uneven rotor surface can push the pads away from the rotor, creating excessive clearance between the components and a low brake pedal.
  • Visible Imperfections: Do the rotors have cracks, hard spots, deep scoring, or heat discoloration? Then they should definitely be replaced.
Brake calipers contain brake pads that squeeze against the brake rotors, creating friction needed to stop the car.

What Does a Brake Disc Do?

There are two different types of braking systems: disc and drum. As was mentioned, disc brake systems rely on disc-shaped brake rotors for stopping power. All modern cars have front disc brakes and many have disc brakes at all four wheels.

Brake rotor operation is straightforward. When you press the brake pedal, pressurized hydraulic fluid flows from the master cylinder and acts on the brake calipers. Each of the brake calipers contains a set of brake pads that squeeze against the brake rotors, creating the friction needed to stop your car.

What to Do If You Think You Have a Bad Brake Rotor

You don’t want to take any chances with your brakes. If you suspect that you have bad brake rotors, diagnose and repair the problem right away.

Here’s a helpful video on how to replace your brake rotor:

In some instances, a brake rotor with an uneven or marred surface can be refinished, rather than replaced, to restore proper operation. But if a rotor is worn beyond specification—or machining it would take it beyond that point—it must be replaced. A rotor must also be retired if it suffers from flaws that cannot be corrected during the resurfacing process.

And one more thing: You should always replace rotors as a pair to ensure optimum braking ability.

Where to Get a New Brake Disc for Your Vehicle

Brake problems, including a worn-out or warped disc, can land you in the nearest hospital or an unscheduled trip to the mechanic if you’re not careful. It’s extremely important to resolve brake issues as soon as possible to keep yourself and your daily driver safe.

CarParts.com is all about giving customers what they need. Enjoy a hassle-free shopping experience when you buy a top-notch brake disc replacement from us. Use our website’s vehicle selector to find a direct-fit brake disc for your ride. You can also use the search filters to find a brake disc that adheres to your preferences.

Our website doesn’t allow any room for low-quality parts. We only offer products that passed the highest quality control standards from industry professionals, so you’re sure to get a replacement brake disc that’s built tough.

Enjoy the perks of high-quality parts minus the expensive price tag with CarParts.com. Our brake discs come with a low-price guarantee, so you’re sure to get the best value for your money.

To start shopping, simply enter your vehicle’s specifications into our website’s vehicle selector. This will narrow down the catalog to compatible brake discs for your ride. You can also call us using our toll-free hotline while our team of round-the-clock customer service representatives takes your call.

Check out our catalog and shop now!

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Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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