How Do You Know If Your Brake Rotors Need to be Replaced?

Your brake system is an important part of your car which is why it’s important to make sure it’s working properly.  Brake rotors are what your brake pads and brake calipers clamp onto to bring your car to a stop.  That’s why if there is a problem with your brake rotors it’s important to get it addressed sooner rather than later.

Vibrations from the brake pedal or inside of the car when braking is usually a sign that your brake rotors are warped and need to be replaced.  Visually inspecting your brake rotors for a lip around the edge and scoring can also indicate that your brake rotors are in need of replacing.  Grinding noises coming from the brakes is also an indicator that your brake rotors need to be replaced.

But there are also other signs or symptoms that your brake rotors need to be replaced that are not as obvious.  So what are the other symptoms that your brake rotors are worn and need to be replaced soon?

1. Vibrations When Braking

When you press on the brake pedal and feel vibrations from the brake pedal this likely means that your brake rotors are warped and need to be replaced.  Brake rotors can become warped when they are subjected to high levels of heat which can cause the metal brake rotor to bend and warp.

The vibration that you are feeling is because the brake rotor surface is no longer smooth and flat which causes the brake pad to pulsate as it runs across the surface of the brake rotor.  Once brake rotors become warped they will need to be replaced as there is no way to properly flatten out the surface of the brake rotor again once they’ve become warped.

2. Lip Around Brake Rotor

One way to tell that your brake rotors need to be replaced is by visually inspecting them to determine if there is a lip around the edge of the brake rotor.  Over time a lip will form on the edge of the brake rotor as the brake pads start to wear into the brake rotor.

While a large groove or lip at the outer most edge of the brake rotor is a sign that the brake rotor is worn, it may not need to be replaced at this point.  If you are unsure if your brake rotors need to be replaced I’d recommend taking your car to a mechanic to have them take a look and give their advice.

3. Brake Rotors Have Scoring

Brake rotors should be smooth and not have many surface imperfections.  If you notice that your brake rotors have scored or have grooves etched into them this can be a sign that your brake rotors need to be replaced.

When replacing your brake rotors it’s always best to replace your brake pads at the same time. Otherwise, you risk causing the same sort of grooves to be etched into the brake rotor from the old brake pad pressing into it.

4. Grinding Noises When Braking

Hearing grinding noises when you are braking is definitely a bad sign and is when you need to inspect your brakes for issues.

A grinding noise when braking can indicate that your brake pads have worn down to the metal backing plate.  When this happens the metal backing plate will grind into the surface of the brake rotor which it’s not designed to do.  As the metal on metal contact occurs this will damage the brake rotor beyond repair and will need to be replaced.

5. Rust Formation

But if you inspect your brake rotors and you notice that rust has started to form around the outer edge, this is usually a sign that your brake rotors will need to be replaced soon.

Another reason why you may hear a grinding noise while braking is that your brake rotors are worn and falling apart.  Brake rotors are designed to have a smooth surface that allows the brake pads to glide around them has they rotate along with the wheels of your car.

Over time the brake rotors that are typically made of steel can begin to rust and fall apart leading to grinding noises as the brake pads are pressed against the brake rotor.

Once rust begins to take hold of your brake rotors it’s best to replace them with new ones as rust is hard to neutralize once it’s started oxidizing and breaking down the steel rotors.

6. Reduced Braking Power

Let’s say you go to stop your car but notice that your brakes no longer stop your car the way they used to.  This can be a symptom that there is something wrong with your brake rotors.

If your brake pads and brake rotors become glazed over this can cause your brakes to not work as effectively as they used to.

Another reason why your braking power may become reduced is because of contaminants that can get on the brake rotor surface causing the brake pads to slide over the brake rotor instead of gripping it to bring your vehicle to a stop.

If you’ve had any brake system or suspension work performed on your car there is a chance that grease or oil got onto your brake rotor making it slippery.

The best way to remove grease or oil from your brake rotors is by using brake cleaner and a clean rag to clean your brake rotor surface.

7. Rotors Have Cracks

Another symptom that your brake rotors are bad is cracks on the brake rotor surface.  Cracks can develop in brake rotors after they have been heated up to extreme temperatures causing the steel brake rotor to form cracks on the surface of the brake rotor.

These cracks are fine as long as they are on the surface level, if you notice that a piece of brake rotor has cracked off it’s a good idea to replace your brake rotor as soon as possible.

Otherwise, you risk your brake rotor breaking into pieces while driving which could damage other parts of your car.  If you notice that your brake rotors have cracks on the surface it’s a good idea to go ahead and get them replaced.

What Should Brake Rotors Look Like When New?

Now that you have seen what brake rotors look like when they need to be replaced you should know what new brake rotors look like so that you can compare yours to new ones that way it gives you an idea as to how worn your brake rotors are.

New brake rotors should look like the brake rotors in the below picture.  If your brake rotors look more worn down than the picture below it doesn’t necessarily mean that your brake rotors need to be replaced.  I just thought it would be useful to be able to visually compare new brake rotors with worn brake rotors.

What Happens If Brake Rotors Are Not Replaced?

Deciding to not ever replace your brake rotors can have dire consequences that can potentially leave you stranded on the side of the road.  Let’s say that your brake rotors are worn now, you have 100,000 miles on your car and the brake rotors have still never been replaced.

Over time your brake pads would wear into the surface of the brake rotor and eventually, cracks would begin to form.  If you still decided against replacing your brake rotors the brake pads would keep wearing away the brake rotor bit by bit.

Until one day the brake rotor would crack and break into pieces likely causing damage to surrounding parts and your wheels.  At that point, you would no longer be able to use that brake at all.

How Do You Know If Your Brake Rotors Are Warped?

Brake rotors by design will be flat and smooth.  Usually, with warped brake rotors, you can’t tell with the naked eye that they are warped.

The easiest way to tell if your brake pads are warped is to feel the brake pedal for vibrations or pulses when braking.  Your brake pedal should feel smooth as you press on it and you should not feel any vibrations under heavy or light braking.  Warped brake rotors will cause the brake pads to move back and forth over the uneven brake rotor surface, this movement can then be felt through the brake pedal and is an indication that your brake rotors need to be replaced.

How Long Should Brake Rotors Last?

Brake rotors like brake pads will wear down based on how the car is driven.  Slamming on your brakes when coming to a stop will cause your brake rotors to wear down more quickly.  Gently applying your brakes to bring you to a stop should allow your brake rotors to last longer.

In general brake rotors can last anywhere from 35,000 to 75,000 miles before needing to be replaced.  But the actual mileage you get out of your brake rotors will vary and will be mainly dependent on how you drive and what materials were used to make your brake pads and rotors.

How Much Does it Cost to Replace Brake Rotors?

Replacement brake rotors can vary widely on your specific car, how large your brake rotors are, and where you buy your replacement brake rotors from.  The larger your brake rotors are the more you can expect to pay for replacement brake rotors.

That means if you have a truck or SUV you can expect to pay more for replacement brake rotors than brake rotors for a sedan.

In general, you can expect to pay anywhere from $120-$200 for a set of front and rear brake rotors.  If you don’t know how to install them yourself you can take them to a mechanic to have them put on.  A mechanic will typically charge $80-$100 per hour to work on brakes.

Where you buy your replacement brake rotors will also determine how much you can expect to pay for them.  You can search on eBay and Amazon for replacement brake rotors for your car and they will be much cheaper than if you went and bought OEM brake rotors through your local dealership.

I’ve purchased replacement brake rotors through Amazon before and can’t really tell the difference between them and the OEM ones I removed from my car.  The one area that the eBay brake rotors were lacking was in paint protection for the wheel hub but I was able to paint my replacement brake rotors at home to keep them from rusting like the OEM ones.