How To Diagnose Failing Brake Rotors

Brake rotor wear is inevitable. Rotors typically last about 50,000 miles (or every 2 or 3 brake pad cycles), but they could wear out faster if:

  • Your car is often used for towing
  • You drive uphill and downhill often
  • You’re usually an aggressive driver

Checking your rotors is a simple and straightforward process that can be done at home. You just need the right tools and a good, easy-to-follow guide (like this one). In this guide, we’ll show you how to identify a bad rotor.

Warning Signs That You Need New Rotors

Replace rotor

Rotors don’t wear out like clockwork. That’s why it’s a good idea to always pay attention for any signs of a bad rotor. Here are a few symptoms to look out for:

  • A pulsating feeling in the brake pedal or steering wheel
  • Squealing, squeaking, or clattering noise when you apply the brakes
  • Longer stopping distance

These symptoms could also mean that your brake pads have worn thin, so you want to take a look at your rotors to ensure that they’re indeed the problem. There are two things that could be wrong with your rotors:

  1. Normal wear and tear: Your rotors have worn thin after repeated contact with the brake pads. This is normal, and it’s usually the reason you should replace your rotors after some time.
  2. Warping: Sometimes your rotors will get warped as a result being overheated on a regular basis. (This can happen if a caliper is sticking.)

To confirm either issue, you would need to do a visual inspection. Here’s how:

Lifting Your Car and Removing the Wheels

In order to remove the wheels, you have to lift your car. You can either lift the whole car with a lift or use a jack and jack stands to lift one end of the car. You can just lift the car enough to take all the weight off of the wheels. Be sure to do it safely.

Before lifting your car, loosen all of the lug nuts by about a quarter of a turn. Once the car’s up in the air, completely remove the lug nuts from one wheel and then carefully pull the wheel off of the car.

At this point, you can inspect your rotor for any warping or excessive wear and tear.

What Does a Warped Rotor Look Like?

That is trick question. You can't actually tell if a rotor is warped with your eyes. You need to use a dial gauge to see if the runout is less than 0.002 inch. If you find runout that is greater than .0002", either the disc is the cause, or maybe the wheel hub is the problem. So you will need to check the wheel hub runout, too.

What Does a Worn Rotor Look Like?

Sometimes it’s obvious that a rotor is worn; sometimes it’s not obvious. If you see any large burn spots and/or cracks, then the rotor is no longer good to use.

Some worn rotors may look okay from a distance, but you’ll notice a lip along the edge and/or excessive thinning up close. A good way to determine if your rotor is too thin is to first find the rotor minimum thickness, which is stamped on the rotor.  Then use a micrometer to measure the thickness. If the number falls below the minimum thickness, then you should replace the rotor right away.

Is it Easy to Replace a Rotor?

OEM Nissan rotor

Regardless of your experience level, you can certainly replace your rotor at home if you have all the right tools. All you have to do is to order a set of replacement rotors (we recommend ordering genuine OEM rotors from us at wholesale pricing). Then find a good model-specific tutorial to follow.

We encourage you to reach out to us with any questions you may have about diagnosing bad rotors.