Blog Car Care Advice How to Know if You Have Bad Rotors: Signs & Diagnosis
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How to Know if You Have Bad Rotors: Signs & Diagnosis

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If your car features disc brakes, you need to keep your brake pads, calipers, and brake rotors in prime condition for your braking system to run smoothly. 

However, odd signs like an annoying screech or a pulsating brake pedal, are a red flag for bad rotors. 

In this article, we’ll list the 11 most common signs of bad rotors and give you two quick ways to determine if you need a brake disc replacement. We’ll also answer some FAQs, including how long you can drive with bad rotors. 

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Let’s dig in.

11 Signs That Indicate Bad Rotors 

Here are some common symptoms indicating it’s time to replace your brake rotor:

1. Noisy Brakes

Weird sounds from your brakes are the most common sign of worn brake rotors. That said, your brakes may produce different noises, indicating various brake issues that may or may not directly relate to your brake rotors. 

These include: 

Irrespective of the source, any sound from your brakes indicates that your rotors are already beyond repair. So you’ll need an auto repair service for replacement. 

2. Corrosion

Occasional rust on the rotors, brake calipers, and brake pads is common during winter or a rainy season, especially if your vehicle is parked outdoors. But rust on new rotors could be a matter of concern. 

If you notice corrosion on the outer edge of your brake rotors, you’ll have to replace them sooner than later. Ignoring it could lead to grinding noises and rough braking. In extreme cases, the rotors and calipers could also get stuck, making the brake rotor replacement an uphill task. 

3. Excessive Vibration

When the rotors are in good condition, the disc brake pads press against the smooth, flat surface of the rotors, causing your vehicle to slow down on braking. But, the resulting friction may generate excessive heat, causing the rotors to warp over time. 

When that happens, the uneven rotor surface causes excessive vibrations that travel to your steering wheel and car seats. 

Note: Steering wheel vibration could also result from a worn wheel bearing. So, it’s best to have a mechanic diagnose the issue. 

4. Brake Pedal Pulsation

In addition to excessive vibration, you may also experience wobbly pedal pulsation. 

This happens when the brake pads fail to maintain proper contact with the rotor surface — usually due to a warped brake rotor

Quick Tip: Using ceramic brake pads and cross-drilled slotted brake rotors can prevent warped rotors by improving heat dissipation.

5. Out-of-Round Rotors

If you spot a lip around the edge of your brake rotor or see the rotor surface thinning out, it could be a bad brake rotor in progress. 

You’ll need a brake repair mechanic to ascertain your rotor thickness. They’ll tell you whether your discs require resurfacing or you need to get a new rotor. 

6. Grooves or Score Marks on Rotor

Repeated contact with bad brake pads can cause grooves and score marks to develop on the rotor surface. Sometimes, bad driving habits could also affect rotor thickness and lead to uneven rotor surfaces. 

Whatever the cause may be, deep grooves or score marks could lead to impaired braking system performance. You should never delay a brake pad and rotor replacement in such cases. 

7. Increased Stopping Distance

In more severe cases, grooves and score marks could reduce the friction and stopping power of your disc brakes (brake fade). 

Result — Your vehicle will take a longer distance to come to a stop. 

Not only does that make driving unpredictable, but also riskier, especially when trying to make an emergency stop.

8. Cracked Rotors 

Exposure to extreme heat can cause your brake discs to crack or form dents on their surface. 

Brake disc cracks only on the surface level won’t hinder your braking performance. But deeper cracks could cause the worn brake rotor to snap in half, becoming a serious safety hazard. 

9. Blue Rotors

If your rotors have developed a blue tint, it could indicate excessive heat. Something to worry about!  

This usually results from riding the brakes — keeping your brakes engaged while driving. But it could also be caused by a misaligned brake caliper or insufficient heat dissipation. 

Blue marks on your brake discs are also a one-way ticket to cracked rotors, faulty calipers, worn shoes, and uneven pad wear. So it’s best to get them checked right away. 

10. Strong Chemical Odors

Any odd smell from your vehicle is never a good sign. Strong chemical odors from your disc brakes could indicate overheated brakes or a faulty brake caliper. You may also notice smoke coming from the affected wheel. 

Faulty calipers are the number one culprit for brake rotors becoming warped or off-balanced. 

The next time you smell chemical odors in your car, pull over immediately and let your bad brakes cold down first. Try driving back to safety using brakes in moderation and call a mechanic ASAP. 

11. Dashboard Brake Lights Illuminate

Any malfunction in your brake system, including worn brake rotors, may trigger the brake warning lights on your vehicle dash. 

You shouldn’t worry if the brake warning light pops on when the parking brake is engaged. But if it stays on after you disengage the parking brake, or while driving or reversing — it’s time to call a professional mechanic. 

If you have been noticing any of these bad brake rotor signs, you can confirm them by following these diagnostic steps. 

How to Diagnose a Bad Rotor?

Here are two surefire ways to assess if you have faulty or warped rotors: 

1. Road Test

Drive your vehicle to a speed of 30 mph and then apply brakes firmly, coming to a complete stop. Look for brake pedal pulsation or vibration in your steering wheel and chassis. 

Any vibration or pulsation could indicate a thickness variation in the rotors. 

If you don’t feel any vibration, increase your speed to 60 mph (on an empty road) and apply the brakes firmly again. If you can feel any pulsation or vibration now, a worn rotor or caliper is at fault. 

2. Visual Inspection

Alternatively, you could do a visual examination to prevent a possible brake failure. 

Note: Only do this if you’re comfortable dealing with brake parts. Otherwise, getting a mechanic’s help is advisable. 

Here’s how: 

A worn brake rotor or deformities in any brake component can help you decide your next course of action.

Now you know the signs pointing toward bad rotors and how to diagnose them. Let’s also address some questions you might have about brake rotors. 

3 FAQs Related to Brake Rotors

Here are answers to some queries related to the brake rotor: 

1. How Do Brake Rotors Work? 

The brake rotor spins with your wheel. 

When the brake pedal is applied, the brake fluid creates pressure and activates the brake caliper. The caliper squeezes the brake pad material against the brake rotor, which creates friction and brings your vehicle to a stop. 

2. How Long Can I Drive With Bad Rotors?

While you can drive for a short period before your brake rotors are entirely worn out, we don’t recommend it. Not only is it hazardous, but it can also increase your brake system repair costs. 

It’s best to get a brake rotor replacement every 30,000 to 70,000 miles to avoid such a situation.  

3. How Can I Increase the Life of My Brakes?

Here’s what you can do to make your braking system last longer: 

Wrapping Up

Remember, driving with a cracked or warped rotor is a one-way ticket to complete brake system failure. It’s better to get them checked and replaced the moment you witness any signs mentioned above. 

If you need a hand with the replacement or bad brakes repair — contact AutoNation Mobile Service

We’re an accessible mobile auto repair service available seven days a week. 

With us, you’ll get the following:

Get in touch with us to get brake pad or rotor replacement, transmission repair, tire rotation, or other tire services!