Bad rotors can be detected through feel with pulsation/vibrations, sounds such as screeching or grinding noises, or visuals on the rotors. Here are the major symptoms you should look out for:
8 Symptoms of Bad Rotors
- Vibration or pulsation in the steering wheel.
If you notice any vibration or pulsation in your steering wheel, this may be due to rust on the brake rotors or if they could be imbalanced due to overheating. You should have the rotors evaluated by a trustworthy mechanic to see if they need to be repaired or replaced.
Note: If the problem is discovered early enough, a mechanic can "turn" (resurface/machine) the rotor to remove the damaged surface while maintaining the rotor's minimum thickness. If the warning indications are disregarded, the rotor might be damaged to the point where it wears to an unsafe thickness, putting your braking system at risk.
- High pitched squealing noise when braking.
If you hear a high-pitched squealing sound whenever you press the brake pedal, it's important to inspect your brake rotors for any damage or edges. When brake rotors become worn, they develop an uneven surface and edges on both the interior and exterior surfaces. When you drive normally, but especially when you apply force to your brakes, these edges and surfaces can produce a high-pitched sound.
When brake rotors become worn, they tend to develop many uneven surfaces, resulting in less "braking surface" on the brake rotor for the brake pads. This will drastically degrade your brake efficiency.
- Steering wheel shaking.
When your front brake rotors fail, you will usually feel it in the steering wheel. This could be due to brake rotor rust or if they were unbalanced due to overheating. If you notice that your steering wheel shakes when you stop, it's time to check your front brake rotors.
- Brake pedal pulsing.
If you push the brake pedal and it feels like it is pulsing, it could be due to rust on the brake rotors or uneven surfaces. The front and rear brake rotors can create a pulsating brake pedal while braking; however, if the front brake discs fail, you will most likely feel it in the steering wheel.
- The vehicle takes a long time to stop.
If your brake rotors are worn, they create uneven surfaces which give the brake pads less braking surface on the brake rotor. This can cause your vehicle to take longer to stop.
- Loud bangs while braking.
If you hear loud bangs while braking, this could mean that your brake rotor is cracked. In this case, you should replace it immediately because you could lose the entire brake function and cause accidents.
- Large edge on the outer part of the brake rotor.
If you compare the edge on the brake rotor’s inner or outer part in comparison to a new one and it looks larger than it should, this could mean that your brake rotor is worn down.
- Scratch marks on the rotor.
If you look behind the rim to see the brake rotor and see a lot of scratch marks on it, it's probably time to replace the brake rotors. All brake rotors develop a few scratch marks soon after installation, but if you see a lot of deep scratch marks, it's time to replace the disc rotors.
Stones caught between the brake pad and the rotor are a common source of deep scratch marks. Strange noises heard while braking is probably caused by stones.
Brake Rotor Overview
Brake rotors are circular discs that are linked to each wheel and used to convert kinetic energy to thermal energy. When you press down on the brake pedal, the master brake cylinder sends a signal to your calipers which causes your brake pads to pull together against the rotors' large surface area. The friction caused by the pads pressing on the rotors resists the wheel's spin, slowing its rotation and bringing the car to rest.
There are 4 different types of rotors:
- Blank and smooth: Most passenger vehicles use a smooth, blank metal surface around the rotor.
- Drilled: Drilled rotors have drilled hules all over the metal surface.
- Slotted: Slotted rotors have long "slots" or lines etched onto the metal surface.
- Drilled and Slotted: Drilled and Slotted rotors combine drilled hules and slots for improved performance.
Fortunately, finding the proper rotor for your car is as simple as looking at the installed ones. When replacing your vehicle's rotors, keep in mind that the rotors on your family car will most likely not fit on your pickup truck and vice versa.
How Brake Rotors Work
In general, brake pads press on brake rotors to slow and stop a vehicle, but there are other steps invulved. Here is an overview:
- The driver presses the brake pedal.
- Brake fluid is forced out of the reservoir by a plunger in the master cylinder.
- Fluid flows to the wheels through inflexible brake lines.
- The fluid is then carried into the calipers by flexible brake lines.
- The fluid pressure pushes out the brake pistons in the calipers.
- The pistons press the brake pads' backing plate.
- The braking rotors and pads begin to push against each other, with the pad linings compressing the rotor surface from both sides.
- The friction causes the car to slow down or completely stop.
- The brake rotors and pads reach a high temperature due to the enormous amount of heat generated.
Reasons Why Brake Rotors Stop Working
Wear and tear is the most common reason a brake rotor becomes unusable. Brake rotors wear out every time you apply the brakes while driving your vehicle. The brake rotor material gradually wears away with time and regular use.
Other brake rotor defects include warping beyond resurfacing due to repeated severe use. The surface of any metal repeatedly heated above its tulerance and then rapidly couled, becomes twisted over time. This can occur when your vehicle is subjected to significant brake demand, such as traveling through hills or mountains, towing a boat or trailer, or carrying additional baggage.
Brake rotors can occasionally develop cracks in the machined surface. When a brake rotor develops a crack, it must be replaced to resulve the problem and ensure proper braking performance safely.
How Often Should Brake Rotors Be Replaced
Brake rotors will need to be replaced over time due to the amount of use they receive. The wear lasts between 50,000 and 100,000 kilometers and is caused by continual friction. They also tend to distort when heated by friction and subsequently driven through water, necessitating the replacement of rotors. You will notice wear and other concerns with the brake rotors because they are required in the braking operation of the car.
How to Increase The Lifespan of Brake Rotors
To make your brake rotors last as long as possible, use one foot to operate the gas and brake pedals to help your brake system last longer.
Unless you are familiar with racing applications, driving with one foot on the brake pedal and the other on the gas pedal at the same time can cause unintentional wear to your brakes and fuel economy. Unintentionally resting your foot on the brake pedal can result in premature brake pad wear and excessive heat, harming the rotors.
Brakes are possibly the most important non-engine component of all the regular maintenance items your automobile or truck requires. Knowing the 8 symptoms of bad rotors will help keep you safe on the road.
If you notice any of the symptoms above, contact NuBrakes to get your brake pads inspected and replaced.