How and When to Replace Rotors

Brake rotors or brake discs are essential assets in a vehicle. They determine the performance of a vehicle's braking system. When it comes to the braking system, brake rotors are indispensable because they are what the brake pads apply pressure to stop the car and the wheels from turning.

Like other components of a braking system, rotors are susceptible to heat. It is the effect of this heat that causes them to wear out quickly. When it begins to wear, it affects the performance of the braking system. It is at this point that you should consider replacing it. However, most people don’t know when to replace rotors.

Motorists or drivers do understand that routine checkups enhance the performance of their cars. In the case of braking systems, they are the parts that do require regular inspection.

If you don't check brake rotors from time to time, the wear may cause rusting, vibrations, and will make a whole lot of scrappy noises. Fortunately for you, we shall explain in this article how and when to replace rotors.

What Are Brake Rotors?

In case you don’t know what brake rotors are, they are metallic or semi-metallic flat discs that aids in the stopping of a vehicle anytime you press the brake pedals. Brake rotors work with calipers and brake pads in the braking system to decelerate the turning of the wheel till it finally stops.


When you apply the brakes, the calipers compress against the brake pads. The brake pads, then compress against the surface of the rotor. This compression produces friction, and that reduces the speed of the rotating wheels until it comes to a full stop.

What Are the Factors that Can Lead to the Wear of a Rotor?


Some brake rotors are more susceptible to wear than others. In other words, the degree at which a rotor wears out varies and depends on the type of material and the driving style. If you drive in the city often, you will likely replace brake pads and rotors more than those who drive in the longer distance.

The material composition of a rotor is essential, and that is why certain materials are best used in manufacturing rotors than some.

Material Composition of Brake Rotors

There are different types of rotors that are made with different materials. These materials include;

Cast iron - This material is the most commonly used material for making rotors. Besides that, the material is weighty and can affect the handling of your vehicle.

Steel - This material thinner than cast iron, weightless, and handles heat better. They are used in most racing cars. However, it is not as durable as the cast iron and susceptible to warping and pulsation.

Layered Steel - Layered steel material is similar to steel, but the difference is this one comes with layered sheets of steel. This means that there are quite many steel laminated. This material is more effective against warp and pulsation. 

Aluminum - This rotor material can dissipate heat swiftly, but the downside of this material is it melts at a lower temperature. It also weighs less and is suitable for motorcycles.

Ceramic - Think of the Ferrari, Aston Martin, and other super-fast cars. The ceramic material is what's used on their rotors. Ceramic has the highest heat capacity and dissipate heat a lot faster than all the materials in this list. When it comes to performance, the ceramic is the highest known performing rotor.

High Carbon - A mixture of iron and carbon is what makes the high carbon material. They can dissipate heat quickly and helps the rotor to avoid cracking under stress and pulsating. However, it is pricey.

When to Replace Rotors

How do you know when it's time to replace your vehicle's rotor? What you must know is brake rotors wear in several ways. Sometimes, the damages are difficult to detect. While it may seem impossible at times to recognize these damages, there are noticeable signs that indicate that it is the right time to get your rotors replaced.

Unlike brakes that have wear indicators, rotors don't. So you have to be observant and be up-to-date with regular checkups to know when it's time to replace a rotor.

These signs include:

Pulsations/Vibrations - When you apply the brakes, vibrations occur till the car comes to a stop. This is not a healthy vibration and is a sign that your rotor may need a replacement.

Bluish discolorations - Sometimes, when you check the surface of the rotor, you may observe that it looks bluish. This is because the rotor isn't able to dissipate heat as it should. The leftover of the heat will form blue rings. It's a sign that you may need rotor replacement.

Deep grooves on the surface of the rotor - A failing rotor will have grooves on its surface against a smooth and flat surface. Grooves arise as a result of constant with the brake pads. This is an indication that you need to replace your rotor.

Extending stops - vibrations, squeaky noises, grooves can affect the response of the brake pads when they press against the rotor. When you apply the brakes, the car doesn’t usually stop when it ought to. Instead, it will give you an extended stop. This translates to a failing rotor and may need immediate replacement.

Warping - Drivers can detect this condition with ease. As the motor wear with age, the pads will no longer make contact with the rotors. This makes it difficult for the brakes to respond whenever you apply the brake pedals. Thus, reducing the braking ability.

These are signs that indicate that you need to do something to your rotor. However, in a situation where early diagnosis is made, you can choose to resurface the rotor to make it smooth and flat. Then, you need to purchase new brake pads because there is every tendency that it may be unequally worn.

However, you can only resurface rotors for a limited amount of time. Resurfacing reduces the thickness, making the rotor thinner. If the rotor should go below the minimum thickness, brake pads and rotors replacement is the best option.

Also, some manufacturers recommend that rotors should be replaced after it exceeds certain mileage, usually between 30,000 - 70, 000. Some manufacturers may recommend more. It’s important to read your vehicle’s manual to be acquainted with such information. So if your brake rotors exceed the recommended mileage, you should replace the rotor as soon as possible.

Sometimes, replacing the rotor isn’t just enough. Replacing the brake pads alongside it will guarantee excellent brake performance. Chances are te brake pads that will be affected by the old rotor. So it’s a good thumb rule to replace brake pads whenever you intend on replacing your brake rotors.

How to Replace Brake Rotors

To replace brake rotors, you will need the following tools:

  • C-clamp.
  • Torque wrench.
  • Brake cleaner.
  • Jack stand
  • WD-40 or any other lubricant.
  • Breaker bar.
  • Thread locker.
  • Anti-seize lubricant.

Steps

  1. Jack up your vehicle. Loosen the nuts.
  2. Remove the wheel nuts and then take off the wheels.
  3. Unfasten the brake caliper at the back of the calipers. To make the process easier, start by loosening the bolt the base before you move to the top. If all the bolts are hard to remove, use lubricants like WD-40.
  4. When you are done, remove the caliper and set it aside. Remove the upper caliper fastener.
  5. Unbolt the caliper from below the knuckle. Use a breaker bar to loosen the fasteners if it refuses to unbolt.
  6. Remove the caliper from the rotating disc. Keep the caliper safe by tieing caliper to a close suspension component with a piece of rope or wire to support it to avoid any damages to the brake lines.
  7. Take off the rotors. If you find it difficult to take them off, use a hammer to hit the surface to break it free. It may be due to dust and friction.
  8. Spray the axle hub with anti-seize lubricant.
  9. Clean the front and rear side of your new rotor with a brake cleaner spray. This will take off any dust or debris.
  10. Use a C-clamp and compress the piston back to the disc, to avoid pulling out.
  11. Put the calipers back on the rotating disc. Start bolting. Ensure you torque the bolts properly. Refer to your manual if you have any misunderstanding.
  12. Lubricate the caliper pins before putting them back. This will enable the brakes and the new caliper to function at the optimum.
  13. Reinstall the wheels and torque the nuts with the torque wrench. 

Do I Need New Brake Rotors

How and When to Replace Rotors FAQs

How do I know when my rotors need to be replaced?

There are many ways to know if your rotors to be replaced. The first sign is usually a cracky or scrappy noise you hear anytime you apply the car brakes. Other signs include deep grooves, brake, vibrations or pulsations, and a burned appearance on the surface of the rotor.

How much does it cost to replace brake pads and rotors?

The average cost of replacing rotors and brake pads could be in the range of $400 and $600. When you factor labor costs, it could be up to $200. The cost of brake pads is in the range of $240 and $400. Total costs could be in the range of $840 and $1200. However,  taxes and fees are excluded. 

How often do brake rotors need to be replaced?

Brake rotors usually last anywhere between 30,000 - 70,000 miles. Sometimes, it may be more, depending on the type of material used in making the surface of the rotor and the driving style. An expert mechanic will access the condition of the rotors and proffer advice on whether you should replace it or not.

Why do rotors need to be replaced?

The safety of the driver and the road performance of the vehicle depends on the condition of the rotor. If the rotor is too thin and cannot maintain or exceed the required minimum thickness, then it needs a replacement. This why rotors to be replaced. To avoid road accidents and ensure the safety of the driver.

Can I just replace the brake pads and not the rotors?

Some manufacturers do recommend that drivers should replace the brake pads and not the brake rotors. As long as the minimum required thickness is maintained, rotors shouldn’t be replaced, but the brake pads.

What happens if I don’t replace brake rotors? 

If you don’t relaxedly brake rotors, it will lead to more wear, pulsation, warping, and more unevenness. Your Anti-Lock Brake system (ABS) could fail at any moment, which means you are liable to get a car accident. Replacing rotors is crucial and is never an option. 

How long can I drive with a bad rotor? 

It depends on the severity of the wear, the type of brake material, driving style, and the recommended manufacturer’s mileage. You can drive on a rotor between 30,000 to 70,000 or even more if the signs of wear are not too severe. However, once you exceed the recommended mileage, you should consider replacing the rotor. 

Do I have to replace all four rotors at once? 

Yes. As far as you have replaced the brake pads, including the rear ones, it’s necessary to replace all four rotors. It’s vital for the safety and efficiency of the brake system. 

What happens if I put new brake pads on bad rotors? 

Putting new brake pads on bad rotors will only reduce the efficiency of the brake pads. The pads won’t make proper contact, which will reduce the braking ability. Each time the brakes presses against the rotor, it damages the pad materials. 

What is the best material for a rotor I should look out for? 

Rotors made with ceramic and high carbon are usually the best type of rotors. Ceramic rotors are mostly used in racing cars like Ferrari. These two materials dissipate heat faster but are expensive. 

Conclusion

Routine checkups can never be over-emphasized. Having your mechanic inspect and access the condition of the brake rotors in your car is a way of preventing the brake systems from failing. Brake rotors don’t last forever. At one point, you may need to change or replace it. If you don’t, you are risking your safety and the safety of other people that may be in your vehicle.

How and when to replace rotors is usually one of the biggest questions drivers ask. Fortunately, this article has explained everything you need to know about replacing rotors. With the right tools, you will be able to return your rotor at home; that is after you have taken it for proper inspection.

John
 

John D. Archer is a mechanical engineer and writer based on the area of automotive accessories at brakeshub.com, A resident expert and professional, John is passionate about all things automotive and loves to share his knowledge. He has good experience in all kind of automotive accessories. He has worked as a chief mechanical engineer in some reputed automotive garage firm.

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