Does your car pull to one side when you brake?
Or do you hear strange brake noises when you hit the brake pedal?
Chances are that your brake system may be suffering from uneven brake pad wear.
But what causes uneven brake pad wear, and when should you ideally get your brake pad checked?
In this article, we’ll go over the top seven causes of uneven brake pad wear. We’ll also answer some common questions regarding the brake pad, including the types of brake pad wear you may encounter.
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Let’s brake in.
7 Causes And Solutions For Uneven Brake Pad Wear
Usually, the front and rear pads wear differently. The car’s momentum puts more strain on the front brakes, which can cause them to create more friction and wear out faster than a rear brake.
However, uneven brake pad wear can result from several other reasons.
Let’s take a look:
1. Disc Thickness Variation
Disc Thickness Variation (DTV) is a mechanical term that refers to a condition when the brake rotors of your vehicle have different levels of thickness.
The brake pad comes in contact with more flat spots of the rotor, which consequently causes the brake pad to wear out faster and more unevenly than the rest of the pads in your car.
This condition can also arise from a sticking brake caliper, rust, corrosion, and frequent slamming on the brake. Dirt and debris between the rotor and the brake pad may also lead to Disc Thickness Variation.
What can you do about it?
First, you can ask a mechanic to iron out the flat spots.
You can also ask them to clean the rotors with a brake cleaner before reinstalling to remove any brake pad dust or rust, as these are the major contributors to brake wear.
However, a mechanic can only smoothen out a rotor so many times before this method becomes ineffective. The only option left to counter the impact of DTV is to get the brake rotor replaced.
And, if the brake rotor and the pad are worn past repair, you should also get your caliper piston and its rubber boot inspected as it may fail to retract properly after being out so far.
2. Caliper Failure
Another common cause of an uneven brake pad is a failed caliper and piston.
A brake caliper contains a piston that exerts pressure on the brake pads to stop the vehicle. Sometimes, the rubber seal that pulls the caliper piston away loses its ability to pull back.
This causes the pad to be in constant contact with the brake rotor and results in faster brake pad wear.
Sometimes, rust or debris on the caliper can also lead to a sticky piston and guide pins, which means that the piston won’t slide efficiently, leading to increased brake pad wear. And in some cases, corrosion from the outer caliper can reach the caliper bore and squeeze the bushings.
What should you do?
When that happens, you should visit an auto repair shop or book a brake service appointment to have an expert look at your brake caliper as well as the guide pins. And, if needed, you can go for a caliper rebuild or brake replacement.
3. Corroded Slide Pin
A slide pin allows the brake caliper to slide back and forth so that the brake pads can come in contact with the rotors.
When these sliding pins become corroded or if you have a stuck piston, they prevent the caliper from sliding smoothly. As a result, the brake caliper gets stuck in one position causing the brake pad to wear out more quickly.
How to get rid of this corrosion?
A quick solution is to use a wire brush and some grease to get rid of the corrosion. And if the slide pins are beyond repair, it’s a good idea to replace them with a new slide pin.
4. Misalignment In The Brake Pads
The correct alignment of a brake pad ensures that it squeezes the rotor evenly.
However, if there’s improper pad installation, it leads to uneven pad wear.
If you have a misaligned brake pad, you’ll notice braking issues within weeks or months of a new brake pad installation.
What can you do about this?
If you think that you have a misaligned brake pad, it’s best to call a mechanic to inspect the installation. They may ask you to hit the brake pedal and check if both the pads squeeze the rotor simultaneously. If not, they can realign them.
5. Corroded Or Dirty Rotors
Sometimes even new rotors can experience brake pad wear when they’re inflicted with dirt or grease accumulated during storage.
What can you do about it?
To ensure that your rotors stay dirt-free, you can get them cleaned with a brake cleaner that doesn’t leave any residue after its solvents evaporate.
You can also ask a mechanic to apply an anti-rust over the rotor during your regular car maintenance to prevent it from rusting over.
6. Warped Rotors
A warped rotor can have a deformed or wavy surface. This usually happens when a hot rotor comes in contact with cold water.
And, when a brake pad comes in contact with a warped rotor, the pad only makes contact with a rotor’s high points. This leads to uneven brake pad wear.
How can you avoid this?
To prevent this, avoid spraying water on your wheels immediately after a long drive. You should give the rotors enough time to cool down.
7. Different Makes Of Brake Pads
You should avoid using braking pads of different companies of a different brake pad material as they’re likely to wear down at different rates.
What’s the solution?
Staying consistent with the brake pad’s model and brake pad thickness will ensure that they wear down evenly.
Now you know the reasons for uneven brake pad wear, let’s address some common brake questions on this topic.
4 Uneven Brake Pad FAQs
Here’re some common pad wear questions and their answers:
1. What Are The Types Of Brake Pad Wear?
In the majority of cases, uneven brake wear usually means more inner pad wear. However, there are situations when the outer pad wears out first or the brake pad tapers.
Let’s see the different types of pad wear and the reasons behind them:
Outer Pad Wear
It’s rare for the outer pad or the outboard pad to wear out first.
For this reason, you hardly see wear sensors for the outer pad.
Outboard pad wearing usually occurs when the friction material of the outer board continues to rub against the rotor even after the caliper piston retracts. The culprits here could be faulty guide pins or stick sliding pins.
To rectify this uneven pad wear, you can call a mechanic to service or replace the caliper guide pins, bushings or go for a complete caliper rebuild.
If the outboard pad wear is more than the recommended levels, you should get new brake pads installed.
Inner Pad Wear
Inner pad or inboard pad wear is a fairly common brake pad wear pattern.
If your vehicle has a floating caliper brake system, the friction material of the inside pad will wear out faster than the outer brake pad.
This is normal.
However, the difference between the pad wear shouldn’t be more than 2-3 mm.
On inspecting a brake’s caliper, if your mechanic finds a more rapid inboard pad wear, most likely the cause is a seized or faulty caliper pin (slide pin).
But that’s not the only reason.
Sometimes the friction material wearing could also be due to a faulty caliper piston that doesn’t return to its resting position. This is probably due to a worn piston seal, corrosion, or damage.
Then, there are times when a fault in the master cylinder leads to rapid inside pad wear. To rectify this, you can call a professional to inspect the hydraulic braking system as well as the caliper for residual brake pressure.
Along with the caliper, they may also check the guide pins and piston boot for corrosion or damage and replace it too.
Tapered Pad Wear
If the friction material on the brake pad is tapered or has a wedged pattern, it could either mean that the caliper has excess movement or that one side of the pad is seized in the bracket.
Sometimes, corrosion under the abutment clip may also prevent one pad ear from moving, leading to tapered wear.
A tapered brake pad wear pattern is normal in some vehicles that have a small rear floating caliper on the rear brake. The brake pad manufacturer will likely mention the specifications of the pad wear in this case.
This kind of uneven brake pad wearing can also be caused by faulty installation or worn guide pins. In that case, you can get the pad reinstalled or buy a brake hardware kit to replace the caliper guide pin bushings.
Cracking, Glazing, Or Lifted Edges On The Pads
Brake pad overheating can cause cracked, glazed, or lifted edges of the friction material.
The high temperatures can be due to excess friction from brake overuse, a defective pad, a stuck parking brake, or a malfunctioning caliper.
As a result, the raw components of the pad can break down. It can even damage the cohesion of the brake pad to the backing plate.
You can get this kind of brake pad wear rectified by replacing and installing a new pad correctly in your disc brake. When you do so, you should also get your parking brake adjusted if it’s on the affected wheel.
2. Are The Backing Plate On A Disc Brake And Drum Brake The Same?
A backing plate in a disc brake simply refers to the metallic surface on the brake pad to which the friction material is glued or riveted.
The backing plate in drum brakes plays a more pivotal role.
It’s a metal plate onto which the wheel cylinder and brake shoes are attached. This metal backing plate provides the necessary grip to stop a vehicle through friction.
How?
When you push the brake pedal, the hydraulic fluid (brake fluid) through the brake line enters the wheel cylinder containing two pistons. These pistons can be found at the top of the backing plate.
The brake fluid forces these pistons outward, pushing the brake shoes against the brake drum. This leads to friction and slows down your vehicle.
3. Can I Change The Brake Pads On One Side Only?
It isn’t a good idea to install new brake pads on one side only as it can lead to further uneven pad wear.
It’s best to replace both front or rear brake pads together.
4. When Should I Ideally Get My Brake Pads Checked?
It’s recommended to get your brake pads checked every 50,000 miles.
However, there are specific brake pad wear symptoms you should keep an eye out for:
- Difficulty in braking
- Shaking steering wheel
- Stopping your vehicle takes more time than usual
- Your vehicle’s nose pulls to one side on braking
- Your brake sqeals or gives a faint scraping or buzzing sound whenever you hit the brake pedal
- You get a clicking sound whenever the brake pedal is pushed or released
Certain electronic braking systems also have abnormal brake pad wear rates because the rear brake controls the nose dive. If you feel that the wear is sooner than expected, you should get the brake system inspected or go for a complete brake job at an auto repair shop.
Parting Thoughts
As you can see, there are several reasons for brake pad wear.
Brake pads are one of the most replaced brake components on a vehicle.
However, the true reason behind excessive friction and uneven wear of a brake unit can only be ascertained by an expert.
That’s where AutoNation Mobile Service steps in.
We’re a mobile auto repair service with ASE-certified technicians. We offer you a host of benefits ranging from a 12-month, 12000-mile warranty to a convenient online booking process.
And if you want an estimate of how much a brake pad replacement will cost you, just fill up this form.