When should you replace your brake rotors? Metallic squealing or grinding noises coming from the brakes, shuddering or shaking, or a steering wheel that pulls to one side when slowing down are all potential indicators that you may need to repair or replace brake rotors or pads on your vehicle.
Luckily, this is a condition that your mechanic can diagnose easily with a simple visual inspection. If you notice these symptoms, it's a good idea to have your brake system checked out as soon as possible, for the sake of your safety on the road and to prevent further parts damage. In some cases, switching out brake pads and resurfacing rotors are enough to fix the issue. However, severely scored or warped parts will likely require brake rotor replacement.
What are brake rotors?
In order to understand when and why to replace brake rotors, it's helpful to know exactly what these auto parts are and how they work. Also known as brake discs, in most vehicles, rotors are metallic discs that are visible through the wheel wells.
These discs work in tandem with brake pads and calipers to slow the rotation of the wheel and bring the vehicle to a halt. This simple hydraulic system is similar to rim brakes on a bicycle. When the brakes are pressed, the calipers squeeze the brake pads against a rotating surface. The resulting frictional force slows the wheels and allows for a fluid stop.
While the brake pads on most bicycles press directly against the wheel rim, the pads on an automobile press against the rotor (brake disc). The rotor itself is bolted onto the wheel hub and spins in sync with the wheel. Because the frictional force needed to stop a vehicle is much higher than that of a bicycle, brake discs are essential for absorbing and dissipating the resulting temperatures and pressures. Here's a quick video we've created that explains how the rotor works and gives you a visual overview of the braking system.
What causes brake pad & rotor problems?
In order for the braking system to work effectively, it is essential that the surface of the rotor is completely smooth and flat. The brake pads should maintain constant contact with the brake disc during deceleration. In cases where the rotor's surface is warped or grooved, the pressure of the pads is inconsistent, resulting in pulsing or shuddering during deceleration.
Scoring and deforming are two of the most common problems with brake discs. Scoring usually occurs when the frictional material on the brake pads has been worn down severely. Once this "padding" is gone, the underlying metal scrapes against the rotor during deceleration. Over time this can lead to deep grooves on the rotor surface.
Disc deformation is typically the result of excessive braking, which can cause severe overheating capable of warping the rotor. Warping can also be the result of another part of the braking system malfunctioning.
How are brake rotors fixed?
In cases where rotor damage isn't too severe, a qualified mechanic may be able to machine the rotor to create a smooth useable surface. New brake pads will need to be installed at the same time. Even if the old pads are in fair condition, the frictional material has probably worn unevenly due to previous rotor damage. Installing new brake pads ensures flush, constant contact with the rotor and smooth braking function.
However, brake discs can only be resurfaced so many times. Manufacturers set a minimum thickness that is required to ensure proper rotor function. Each time a disc is machined, material is removed and the part is less able to absorb and dissipate heat. This makes the rotor more likely to warp during use, compromising braking function and posing a potential risk of damage to other vehicle parts. A certified technician should be able to give an informed recommendation as to whether resurfacing makes sense or you need a brake rotor replacement.
Because rotor design and composition vary between different makes and models, the expected lifetime of the part will also vary. Knowing when to replace brake rotors will also depend on the type of driving you do. If you mostly drive in the city, you will probably need to replace brake rotors and pads more than if most of your driving is longer distance. To avoid having to switch out rotors prematurely, it's important to replace the brake pads routinely. The best way to avoid brake system issues is to have your mechanic perform a routine inspection during your regular oil change.
If you are concerned that your brakes aren’t performing as they should, or you just need some routine maintenance, Sun Auto Service has you covered. Our technicians are ASE certified, and we offer complimentary brake inspections on all types of vehicles. In addition to checking your braking system, we'll give you specific advice for your vehicle about how often to install new rotors and pads. With multiple Sun Auto Service locations in both the Las Vegas, Nevada and Austin, Texas areas, you're sure to find a service center near you.