Once you depress the brake pedal, the applied force will push hydraulics, forcing the pistons in the caliper to push the brake pads against the brake disc. The brake pads are made of friction material that clamps down the rotor as you apply the brakes. This friction material will wear off evenly on both sides.
While this is how the friction materials are designed to wear off, there are situations where you may notice uneven wear on brake pads. This prompts many car owners to ask, what does uneven wear on brake pads mean?
Whenever you have uneven brake pad wear on one side, you have to change both sides of the brakes because both brakes have to be equal. Replacing the brakes at different intervals will compromise the efficiency of the brake system. Therefore, this article will discuss the probable causes and how to fix uneven brake pad wear.
What causes uneven wear on brake pads
As explained above, brake pads are supposed to wear out evenly. So uneven brake pad wear shows there’s an issue in the braking system that needs attention. Here are the probable reasons your brake pads are not wearing evenly.
One of the significant reasons brake pads wear off unevenly is caliper and piston issues. The brake caliper houses a piston that pushes the pads against the rotor to slow or bring the vehicle to a stop when you depress the pedal. If, for any reason, the caliper piston fails to pull back to its original position as you release the pedal, it’ll cause the pads to be in constant contact with the rotor.
This will invariably cause only one brake pad worn if it is happening to a particular wheel. This situation is mainly caused by issues with the rubber seals on the caliper, debris, or rust leading to sticky guide pins and pistons, affecting how the pistons move in and out.
Corroded slide pins
The slide pins are one of the essential but overlooked brake system components. They allow the caliper to move back and forth, so the pistons push the pads against the brake disc. If these slide pins get rusted, they won’t allow the caliper to move smoothly.
Each caliper has at least two slide pins. If one of them gets rusted, it won’t allow smooth movement on that side of the caliper, causing brake pads not touching the whole disc. Of course, this means uneven wear.
Warped rotors usually have wavy or deformed surfaces. These are typically caused by excessive heat on the brake disc and hard braking. And when the pistons push the pads against the rotor, they only make contacts on the high points of the disc.
If this happens on the front wheel, it will lead to uneven wear on the front brake pads. And if it happens on the rear wheels, it’ll also cause uneven wear on the rear wheels.
Different brake pad brands
There are different types of brake pads based on the materials used in production. These brakes wear at different intervals. If you install brake pads from different brands on the same car, they will not wear at the same rate.
Dirty or corroded brake disc
Brake discs can get dirty or corroded in several ways. For instance, new rotors can get dirty or accumulate grease or other contaminants from the storage. Also, parking your vehicle under the rain for weeks or months during the rainy season will rust the pads and the rotors.
And driving the vehicle without cleaning the rotor and pads will cause uneven wear on the bike brake pads or car brake pads. You’ll hear grinding noises from the brakes if a rusty disc is the culprit.
Improper brake pads installation
This is common with DIYers and amateur mechanics. Proper alignment and installation ensure the brake pads hug the discs perfectly. If you did not align the pads properly during installation, it’d cause the pads to wear quickly and unevenly.
You’ll start hearing grinding noises from the wheels and noticing rust or excessive heat on the wheels within the first few days.
Disc thickness variation
Disc thickness variation (DTV) is an automotive terminology that points to a disc with varying thickness levels. If your brake rotor has DTV, the brake pads will not hug the disc perfectly. The spot with more thickness will cause the pads to wear unevenly.
At this point, you will no longer ask what does it mean when one brake pad wears unevenly. I’ve outlined the possible causes. Now, let’s see how to fix uneven brake pad wear.
How do you fix uneven brake pads?
As seen above, several parameters can cause uneven wear on the brake pads. Therefore there are several ways to fix the underlying problem, depending on the root cause. After a thorough diagnosis, you’ll need one or more of the following repairs to fix the problem.
Machine the rotor
If the brake pads are wearing off unevenly due to disc thickness variation (DTV), the only solution is to take the rotor to a machine shop. The service technicians there will resurface the rotor. After that, replace the old brake pads with new ones.
Fix caliper failure issues
If caliper failure is the leading cause, contact a mechanic to service the brakes or, better still, rebuild or replace the caliper. If you choose to service the brakes yourself, remember to smooth the guide pins.
Clean corroded or rusted slide pins
If both slide pins are not freely moving back and forth, remove and clean them with a wire brush. Also, clean the pin wells and grease the pins before reinstalling them. Replace the dust boots if torn to prevent the pins from rusting again. Consider getting new slide pins if the old ones are bent or beyond cleaning.
Inspect and realign the brake pads
If you hear grinding noise after replacing old pads and think they are not properly aligned, have a mechanic inspect them. It could be there’s a wrong installation. If you want to check the alignment, have an assistant depress the pedal while you check if the pads hug the rotor evenly.
If there’s a wrong installation, correct it and see if that rectifies the underlying problem.
Clean the rotors
As the saying goes, prevention is better than cure. If you notice a rusted rotor, clean the rust by sandpapering the disc with smooth sandpaper. After that, clean the disc with a brake cleaner and ensure no residues are left on the surface. Resurface or replace the pads.
Do not use different brake pad brands.
Refrain from using different brake pad brands at the same time. This will help to ensure the pads wear out evenly. And finally, do not pour water on the rotor immediately after driving, even if the wheels are overheating.
Frequently Asked Questions – FAQs
Q: Are brake pads supposed to wear evenly?
Car manufacturers design the braking systems to wear out evenly to distribute even braking power to the wheels. However, brake pads sometimes wear off unevenly due to several factors like caliper issues, rusted discs, brake pad misalignment, disc thickness variation, and improper installation.
Q: What causes brake pads to wear more on one side than the other?
Brake pads wearing more on one side indicate that something is wrong on that side. The most common causes include caliper issues, rusted slide pins, and warped rotors. Other probable causes include improper installation, rusted discs, and disc thick variation. So, if you find yourself in a situation where the disc wears more on one side, one or more of the outlined issues is the culprit.
Q: Can brake pads wear out in 3 months?
Typically, brake pads should last more than three months. Brake pads should wear off between 20,000 and 35,000 miles, depending on the type of pads. However, brake pads can wear out quickly in 3 months or so. You may be asking what causes brake pads to wear out quickly. Issues like road conditions, the type and quality of brake pad material, braking style, and overall condition of the calipers & rotors cause brakes to wear out quickly.
Q: Do brake pads wear faster if you drive slow?
No. Braking at higher speeds affects the brakes much more than when braking at lower speeds. Rapid or hard braking is one of the common reasons brake pads wear out quickly. And spirited drivers brake more than average drivers because they often hit the brakes harder than slow drivers.
Q: How can I extend the life of my brake pads?
This article has outlined why brakes wear out unevenly and quickly along with ways how to rectify the problem. However, it’s better to prevent something from happening than proffering solutions. Here are the things you can do to extend the lifespan of your brakes;
- Avoid unnecessary brake taps
- Slow down on high speeds
- Always maintain enough braking distance
- Do not overload your vehicle
- Don’t brake with the left foot
- Flush brake fluids when necessary
- Do regular brake maintenance
- Buy quality brakes.
As reiterated above, there are several reasons for uneven wear on brake pads. Braking pads are essential braking system components that require replacement more often than others. However, they are designed to wear evenly.
Of course, this article has briefed on the probable causes of uneven pad wear, but the real challenge is identifying the root cause. Always inspect the aforementioned probable causes to track and rectify the actual culprit in your case. Contact a mechanic for thorough inspection and repair if you’re not the DIYer.