This article was co-authored by Matthew Rava
and by wikiHow staff writer, Bailey Cho
. Matthew Rava is an Auto Repair Expert and the Co-founder & Head of Marketing of Brakes to You. He specializes in auto repairs that concern brakes. Matthew earned a BS from West Chester University of Pennsylvania.
There are 23 references
cited in this article, which can be found at the bottom of the page.
This article has been fact-checked, ensuring the accuracy of any cited facts and confirming the authority of its sources.
This article has been viewed 39,781 times.
Has your steering wheel been vibrating recently? Or, have your brakes made an annoying screech every time you hit the pedal? If so, it’s definitely a sign to inspect your brake system. All brake rotors wear out naturally, but overworn rotors can cause issues with your wheels and braking system. In this article, we’ll go over all the signs that your brake rotors aren’t working properly (plus, how to determine if you need to replace them). If you notice any signs of a bad rotor, take your car to the nearest shop and have your mechanic replace them immediately.
Things You Should Know
- If your steering wheel or brakes vibrate, it usually means your rotors are warped or grooved.
- Blue coloration often indicates prolonged braking, which can lead to overheated rotors.
- Corrosion decreases the friction between the rotor and brake pad, reducing your braking power.
- If you have any signs of a bad rotor, replace them immediately. Additionally, inspect your rotors regularly and replace them after 60-70,000 miles.
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Vibrations mean your rotors are warped. When braking, your brake pads press down on your rotors, creating friction and heat. Over time, this pressure warps your rotors and makes them uneven, causing a shaky steering wheel. [1] X Research source
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Noisy brakes indicate your rotors aren’t smooth. When your brake pads wear down, their metal backing plate begins to grind against your rotor. Since metal is grinding against metal, this interaction ruins the smooth surface of your rotors, causing a grinding or screeching noise when you step on your brakes. [4] X Research source
- Inspect your brake pad to see how much material is remaining. You may have to remove your wheel to see behind the backing plate, but check if there’s at least 4 mm (0.4 cm) of padding left. [5] X Research source
- Alternatively, grinding brakes can be caused if your brake pads aren’t broken in. To break them in, accelerate to 30-40 MPH before quickly coming to a stop, and then repeat 4-5 times.
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Pulsing signals unevenly worn rotors. If your rotor isn’t perfectly flat, it doesn’t properly align with the surface of your brake pads, causing a wobbly or shuddering sensation. Uneven wear is usually caused by overheated rotors or worn out brake pads. [6] X Research source
- Alternatively, uneven rotor wear can be attributed to poor quality control by the manufacturer, so be sure to install high-quality parts for your brake system. [7] X Research source
- It only takes around 0.001 inches (0.003 cm) of thickness variation on the rotor’s surface to cause noticeable vibrations. [8] X Research source
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Reduced braking power often indicates glazed pads and rotors. When your brake pads overheat, the outer material hardens and transfers to your rotors. Since the material breaks down, it disrupts the friction between your pads and rotors, resulting in poor brake performance. [9] X Research source
- Alternatively, reduced braking power may occur because there’s oil or grease on your rotors, preventing the brake pads from gripping them. If you’ve done work on your car recently, inspect the surface of your rotors, and use brake cleaner to remove any contaminants.
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Blue spots show up on your rotor from prolonged braking. The longer you press your brake pedal, the more friction and heat is exposed to your rotor. Over time, this takes a toll on your rotors, especially for drivers who “ride their brakes” to descend hills, curved roads, or mountainous areas. [10] X Research source
- Normal rotors are silver or gray, unless they’re painted with a custom color. [11] X Research source
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Grooved rotors develop from repeated contact with the brake pads. When your rotors are constantly exposed to heat and friction, they develop score marks or grooves, similar to the lines on a vinyl record. Left untreated, these indents can lead to braking and steering failure because they prevent your rotor from laying flat against the brake pads. [12] X Research source
- Alternatively, visible score marks can form prematurely if there’s a rock stuck between your rotor and rotor shield. If your brakes are acting up, take off your wheel and check the area between your rotor and dust shield. If something’s stuck, you can easily bend the dust shield and let it fall out. [13] X Research source
- If your rotors are in good condition, they should have a smooth surface with minimal imperfections. [14] X Research source
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Corrosion occurs when your rotors are exposed to moisture. Since most rotors are made of steel, they’re particularly susceptible to rust. Rain, snow, sleet, and humid conditions can cause surface rust to form in as little as a week, but built-up rust can completely eat away your rotor and create an uneven surface. [15] X Research source Rust minimizes the stopping ability of your brake pads, which can cause noise and vibrations. [16] X Research source
- A little surface rust is perfectly normal, but rust builds up quickly if you haven’t engaged your brakes in a while. Be sure to inspect your rotors before driving if you’ve left your car parked for 3-4 weeks.
- Clean your rotors and brake pads regularly to remove any built-up debris. If there’s a thin layer of rust, you can simply scrub it off with a wire brush and brake cleaner. [17] X Research source
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A lip forms on the edge of your rotor when your brake pads wear into it. When your rotor is worn and uneven, it cannot lay flat against the brake pad. Since your brake pad is only able to press against the inner portion of your rotor, it creates a noticeable ridge near the outer edge. [18] X Research source
- To check for a lip, you don’t have to remove your tire. Place your finger on the rotor (the metal disc directly inside the cutout area of your wheels), and feel for a raised area on the outer edge. [19] X Research source
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Thin brake pads wear down your rotors and lead to braking problems. Over time, brake pads become thinner with wear, but once their metal backing plate is exposed, it grinds against your rotor and deteriorates it. This can lead to noisy brakes or reduced braking power, so be sure to inspect the thickness of your pads regularly. [20] X Research source
- To measure your brake pad, remove the wheel of your car and locate the pad between the backing plate and rotor. Place a brake pad gauge from the bottom to the top edge of the brake pad, and repeat this measurement at several points to ensure the pad has even thickness. [21] X Research source
- Depending on your vehicle, brake pad thickness varies, but most manufacturers don’t recommend driving with pads thinner than 6.35 mm (0.25 in). [22] X Research source
- Generally, brake pads last 25-60,000 miles, but be sure to measure them if you notice any sounds or vibrations coming from your brakes.
- A set of front and rear replacement brake pads range from $50-160, but expect to pay anywhere between $200-500 to have them installed.
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Worn-out rotors crack easily, which can lead to brake failure. Although rotors wear down naturally with age, thin rotors are more susceptible to breakage. To make sure your rotor is safe for the road, check the minimum thickness stamped by the manufacturer on the outer edge or center hat section. [23] X Research source
- To measure your rotor’s thickness, remove the lug nuts and tire and take off the rotor. Use a caliper to measure the rotor at its thinnest point, and then measure at different spots to ensure it has an even surface. [24] X Research source
- Depending on the rotor and manufacturer, the minimum thickness varies, but it’s often 2 mm (0.2 cm) less than a brand new rotor. [25] X Research source
- Thin rotors are also dangerous because they can’t absorb and dissipate heat well, increasing the risk of your brake pads overheating.
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High-mileage vehicles require frequent rotor replacement. When it’s time to replace your brake pads, inspect your rotors too. Rotors are designed to last between 60-70,000 miles, but aggressive driving, thin brake pads, and corrosion can contribute to a shorter life span. [26] X Research source
- If you don’t have any steering or braking issues, your mechanic may surface your rotors instead of replacing them. This involves smoothing out any surface irregularities with a brake lathe. [27] X Research source
- Never resurface your rotors without measuring them first—be sure they haven’t worn down to their minimum thickness.
- Usually, it’s cheaper to replace your rotors than to resurface them. Rotor resurfacing costs around $60 per rotor, while conventional rotor replacement is about $30. [28] X Research source
- If your rotors have any cracks, grooves, rusting, or blue spots, go ahead and replace them—these are often signs of irreversible damage. [29] X Research source
Expert Q&A
Tips
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References
- ↑ https://youtu.be/jIW0rouW-j0?t=102
- ↑ https://drivecave.com/bad-brake-rotor-symptoms
- ↑ https://my.safetyfirst.com/newsfart/maintenancecostsr1.pdf
- ↑ https://drivecave.com/bad-brake-rotor-symptoms
- ↑ https://drivecave.com/brakes-squeaking
- ↑ https://drivecave.com/bad-brake-rotor-symptoms
- ↑ https://www.tirereview.com/brake-rotors-when-to-resurface-and-when-to-replace-2
- ↑ https://www.tirereview.com/brake-rotors-when-to-resurface-and-when-to-replace-2
- ↑ https://drivecave.com/bad-brake-rotor-symptoms
- ↑ https://youtu.be/iCBAiuWiwO4?t=293
- ↑ https://youtu.be/58nUkReT8LY?t=63
- ↑ https://youtu.be/RphiSj6aVjw?t=568
- ↑ https://mechanicask.com/rock-stuck-in-brakes
- ↑ https://drivecave.com/bad-brake-rotor-symptoms
- ↑ https://www.tirereview.com/brake-rotors-when-to-resurface-and-when-to-replace-2
- ↑ https://youtu.be/KacBudI-Nqc?t=27
- ↑ https://rustconverters.net/brake-rotors-rust-removal-tips
- ↑ https://youtu.be/RphiSj6aVjw?t=468
- ↑ https://youtu.be/jIW0rouW-j0?t=43
- ↑ https://drivecave.com/bad-or-worn-brake-pads-symptoms
- ↑ https://youtu.be/Ipo6bTIHM5o?t=525
- ↑ https://www.govinfo.gov/content/pkg/CFR-2008-title49-vol5/pdf/CFR-2008-title49-vol5-sec393-47.pdf
- ↑ https://www.counterman.com/replace-brake-rotors
- ↑ https://youtu.be/A9PaWckcOdA?t=61
- ↑ https://youtu.be/7J1nhYbMH-0?t=251
- ↑ https://youtu.be/RphiSj6aVjw?t=460
- ↑ https://www.tirereview.com/on-car-brake-lathes-save-time-on-rotor-resurfacing/
- ↑ https://www.cartalk.com/content/today-when-replace-brake-rotors
- ↑ https://www.tirereview.com/resurface-or-replace-rotors-which-is-better/