Common Failures From A Warped Or Bent Rotor: Symptoms, Questions And More!
Brake rotors are a critical part of any disc brake system. Although rotors are usually made of durable cast iron, over time they can develop uneven wear that causes the brake pedal to throb. Such wear is often referred to as “warping.” It is recommended that you know and inform yourself about the common failures for a bent rotor, so that you can recognize the problems before they get worse.
When rotors warp, you’ll likely notice one or more bothersome symptoms that you’ll want to address immediately.
What is a warped or warped brake rotor?
Brake rotors (also known as brake discs) are found in disc brake systems. Most vehicles have disc brakes at all four corners (one behind each wheel), although some have discs in the front and drums in the rear. When the brakes are applied, a pair of brake pads are pressed against the rotor , creating friction and braking the corresponding wheel to bring the vehicle to a stop.
The term “warped rotor” is often used to describe a rotor that is worn in such a way that it causes a pulsating brake pedal. In reality, however, the rotor is not actually warped, but rather has excessive thickness variation (parallelism) or side-to-side rotational motion (eccentricity). Even so, it is common for both vehicle owners and professionals to refer to the problem as warp.
Symptoms and common failures due to a twisted rotor
Do you think you may have a warped brake disc? If you notice one or more of the following symptoms, you could be right. Avoid any of these common bent rotor failures by knowing the problems below:
1. Pedal pulsation when braking
The most common sign of warped rotors is a pulsation you feel in the brake pedal when braking. Why is this happening? Because the uneven surface finish causes the brake pads to pop off and away from the rotors .
2. Vibration in the steering wheel when braking
In some cases, you may also notice that warped rotors cause a vibration that is felt in the steering wheel while braking.
3. Abnormal noises
Rotors with uneven surface wear can make a rattling noise when in contact with the brake pads. A clang may also be heard when the brakes are applied.
Frequent questions
Below we will be showing you some of the frequently asked questions regarding common failures due to a bent rotor and their answers, in case you have any of these questions.
1. Can you feel a warped rotor while driving?
You’ll usually feel the pulsation of a warped rotor when braking, but not when driving off the brake pedal.
2. How can you tell if the front or rear rotors are warped?
Do you feel a pulsation under braking, indicating that your car’s rotors might be warped? Some say you can tell if the front or rear rotors are to blame by looking at the source of the pulsation.
The theory is that the front rotors are probably to blame if the pulsation is felt in both the steering wheel and the brake pedal. On the other hand, if the feeling is only in the brake pedal, then the rear rotors are probably to blame.
Another popular test method is to apply the parking brake while stopped. If the pulsation disappears with the parking brake applied (affecting the rear brakes), it is likely that the front rotors are warped.
Unfortunately, these evaluations are not always conclusive . The most accurate way to determine if the front or rear brakes are causing pulsation involves performing a visual inspection and then measuring the parallelism and runout of the rotors. Parallelism is measured with a micrometer, while eccentricity is checked with a dial indicator.
But very few technicians (and even fewer DIYers) bother to measure parallelism and runout. Instead, most just take a guess as to which set of rotors needs to be serviced or replaced.
3. How much does it cost to fix a warped rotor?
In some cases, you can have a rotor reground (machined) by a professional to fix a warp problem. But the rotor must be replaced if it is visibly damaged or if dressing causes it to fall below the minimum thickness specification.
You can usually pay $100-$200 to have your car’s rotors reground by a professional; replacement usually costs between $300 and $600. Of course, the exact cost of the repair will depend on several factors, such as the type of vehicle you have and the body shop you choose.
