Brake pad thickness is a measure of how much friction material the pads have to perform braking actions. It helps assess your brakes’ effectiveness and when they might need replacing.
Why is it important?
Insufficient brake pad thickness can cause squealing noises, reduce braking power, and even damage the braking system.
Ignore it, and you put your safety — and that of others — at risk.
Curious about how to inspect your brake pads?
This guide covers everything you need to know, from ideal brake pad thickness to signs of wear and tips for keeping your brakes in top condition.
This Article Contains:
- What’s the Ideal Brake Pad Thickness?
- How to Tell if Your Brake Pads are Worn: 7 Prominent Signs
- What Causes Brake Pad Wear?
- How to Check Brake Pad Thickness: Step-By-Step
- How Often Should You Check Brake Pad Thickness?
- 5 FAQs About Brake Pads
What’s the Ideal Brake Pad Thickness?
Brake pad thickness can differ depending on the type and brand of the pads as well as the design of your vehicle’s brake system. Typically, new brake pads measure around 10 to 15 millimeters (0.39 to 0.59 inches) in thickness. This measurement includes the friction material and the metal backing plate.
As the pads wear down, their friction material becomes thinner, reducing effectiveness and posing safety risks. Regularly checking the thickness is essential to ensure it hasn’t dropped below the recommended level, typically around 5 millimeters (0.19 inches).
If the pads are between 3 to 4 millimeters thick, it’s time to replace them, as 3 millimeters (0.11 inches) is generally considered the absolute minimum brake pad thickness for safe operation.
Understanding the ideal brake pad thickness is essential, but knowing how to recognize the signs of wear is just as important to ensure your brakes stay in top condition.
How to Tell if Your Brake Pads are Worn: 7 Prominent Signs
Here are some key indicators that your brake pads may be worn and it’s time for a brake job:
- Brake warning light: Some cars have sensors that monitor your brake pads. If your brake warning light comes on, it’s a clear sign that you should have your pads inspected.
- Unusual noises while braking: If you hear a squealing or squeaking noise, it could be the brake pads’ built-in wear indicators signaling it’s time for a replacement. On the other hand, a grinding noise usually means the pads are completely worn down, and the metal backing plate is now scraping against the rotor. This situation can lead to severe damage if not addressed promptly.
- Reduced braking performance: When your car takes longer to stop than usual, it’s usually due to worn pads that aren’t providing enough friction. This can make stopping safely more difficult.
- Spongy brake pedal: If the brake pedal feels spongy or soft when pressed, it could mean your brake pads are worn out. If you also experience vibrations or pulsations during braking, it may suggest unevenly worn pads or warped rotors, both of which require prompt attention.
NOTE: A spongy pedal can also be due to air in the brake lines.
- Car pulling to one side: If your car pulls to one side when you brake, it could be unevenly worn pads or an issue with the brake caliper.
- Burning smell: A burning smell after heavy braking can indicate brake fade, which occurs when overheated or worn brake pads lose their effectiveness. Overheated pads can also damage other brake components, such as rotors or calipers, so it’s something to address immediately.
- Thin brake pads: During a visual inspection, if your brake pads look noticeably thin — typically less than 3 to 4 millimeters — they need replacing.
Now that you know how to identify worn brake pads, let’s explore the common factors contributing to their wear and tear.
What Causes Brake Pad Wear?
Numerous factors can contribute to brake pad wear, many of which are influenced by your driving habits, environment, and vehicle maintenance.
- Sticking sliders: Over time, the guides (or sliders) that allow brake pads to move freely can become dirty or corroded. When this happens, the pads may not fully release their pressure on the brake rotor, leading to constant contact with the brake disc and accelerated wear.
- Seized calipers: When the piston inside the brake caliper gets stuck or seizes up, it can keep pressing the brake pads against the rotor. This constant contact causes a squeaking noise and uneven wear.
- Driving habits: Frequent hard braking, high-speed driving, and stop-and-go traffic can accelerate brake pad wear by increasing heat and friction.
- Environmental conditions: Exposure to dirt, water, and road salt can cause corrosion, which may shorten the lifespan of your brake pads.
- Poor bake pad quality: More affordable pads may wear out faster than high-quality ceramic or semi-metallic options.
- Improper installation: Misaligned brake pads can cause uneven or premature wear.
Wondering how to examine the thickness and look for signs of brake pad wear?
Let’s find out.
How to Check Brake Pad Thickness: Step-By-Step
If you’re experiencing symptoms of worn brake pads, it’s a good idea to have them inspected by a trained mechanic. This guarantees a proper diagnosis and correct installation.
Here’s a brief guide on how they would check your front and rear brake pads:
- The mechanic will securely park your vehicle on a flat surface, engage the emergency or parking brake, and place wheel chocks behind each rear tire.
- Next, they’ll inspect the brake pads, which can be done in two ways:
- Without removing the wheel: If the vehicle design allows it, they’ll shine a flashlight through the wheel spokes to examine the thickness of the brake pads. They’ll also check if the pad material is pressed against the brake rotor and look for other signs of wear.
- Removing the wheel: If the pads aren’t visible through the wheel spokes, they’ll loosen the lug nuts with a tire iron, lift the car with a jack, and secure it with jack stands. Then, they’ll remove the wheel to better view the brake components.
- Without removing the wheel: If the vehicle design allows it, they’ll shine a flashlight through the wheel spokes to examine the thickness of the brake pads. They’ll also check if the pad material is pressed against the brake rotor and look for other signs of wear.
- Using a brake pad thickness gauge, ruler, or calipers, they’ll measure the remaining thickness of the pad’s friction material, excluding the backing plate. Then, they’ll compare the measurement to the manufacturer’s recommended minimum thickness.
- If the brake pad thickness is less than the ideal recommended level (usually 5 mm), the mechanic will install a new brake pad set.
- Finally, they’ll reassemble any components that were removed during diagnosis or replacement. If they had removed the wheel, they’d reattach it securely and tighten the lug nuts. They’ll lower the car, remove the jack stands, and release the parking brake to take the vehicle for a test drive.
Next, let’s look at how frequently you should have your brakes checked to keep your vehicle’s braking system in top shape.
How Often Should You Check Brake Pad Thickness?
It’s important to have a yearly break inspection by a professional as part of your regular vehicle maintenance. Typically, you should have new pads installed every 20,000 to 60,000 miles, depending on your driving habits and the type of pads your car uses.
But if you often tow heavy loads or drive in stop-and-go traffic, you should get it checked every 6 months or during each oil change. Mechanics may also check your brake fluid during these inspections, as low fluid levels can sometimes signal other issues in the braking system.
Regularly checking your vehicle’s braking system and installing new brake pads when necessary ensures everything remains in good working condition and helps catch potential issues early.
Got more questions about brake pads?
Check out these FAQs.
5 FAQs About Brake Pads
Here are answers to five commonly asked questions about brake pads:
1. How Do Brake Pads Work?
Brake pads are a crucial part of a disc brake system. They work with the rotors to slow down and stop the car.
When you step on the brake pedal, the brake fluid transfers hydraulic pressure to the calipers, squeezing the pads against the spinning rotor and creating friction. This friction transforms the kinetic energy of the moving vehicle into heat, effectively slowing it down or bringing it to a stop. The pads are made with a special friction material designed to withstand high temperatures and wear over time.
2. What Happens if You Don’t Change Worn Brake Pads?
Failing to replace worn brake pads can seriously affect your car’s safety and performance. It may also significantly increase your repair costs.
Here’s what can happen:
- Reduced braking efficiency
- Noisy brakes
- Brake rotor damage
- Overheated braking system and brake fade
3. What are the Different Types of Brake Pads?
Brake pads come in various types, each made from unique materials. The main types are:
- Organic: Also known as non-asbestos organic (NAO) pads, these are made from materials like rubber, glass, and resin. They’re generally quiet and gentle on brake rotors, but their brake pad material wears out faster and produces more brake dust than other types.
- Semi-metallic: These pads are made from a mix of metal fibers and other materials, providing excellent durability and effective heat dissipation. They offer reliable performance across various driving conditions but can be noisier and may cause more wear on rotors.
- Ceramic: Made from dense ceramic materials with embedded copper fibers, ceramic pads are known for their longevity, quiet operation, and minimal brake dust production. They maintain consistent performance but are typically more expensive than other brake pad material types.
4. How Do You Check the Rear Drum Brakes?
If your car has drum brakes in the rear, that means it uses brake shoes instead of rear brake pads. They serve the same function as rear pads.
That said, the process for checking them is slightly different from inspecting brake pads in disc brakes, so it’s best to get help from a mechanic.
Here’s a brief look at the steps involved:
- Remove the brake drum: The mechanic will remove the rear wheel and carefully slide off the brake drum. If it’s stuck, they may use a rubber mallet to gently tap it loose.
- Inspect the brake shoes: They’ll check the lining of the brake shoes in the rear brakes. The friction material should be at least 3mm thick. If it’s not, they’ll replace them.
- Examine the drum and other components: They’ll look for grooves or scoring on the drum to ensure the springs and adjusters are in good condition.
- Reassemble and test: Finally, they’ll reattach the brake drum and wheel. Then, they’ll take the car for a short test drive to confirm that the rear brakes are functioning smoothly.
NOTE: Drum brakes can be more complex and often require more work to disassemble, so mechanics may charge more for brake services involving drum brake inspections compared to disc brakes.
5. How Much Does it Cost to Replace Worn Brake Pads?
Depending on the cost of parts and labor in your area, you can expect to pay anywhere from $115 to $320 per axle for brake pad replacement. If your rotors also need replacing, it can add another $290 to $400 per axle to the final bill.
A full brake service — replacing the pads, rotors, and calipers — ranges from $950 to $1,300. Opting for aftermarket over OEM parts may help reduce costs slightly.
Stay Safe with Reliable Brake Pad Repair from AutoNation Mobile Service
Brake pads are critical to your car’s braking system, ensuring safe and reliable stopping power. However, when they wear down (below 3mm), they can compromise your safety.
Not sure how to handle worn brake pads?
AutoNation Mobile Service is here to help!
Our mobile mechanics can replace your brake pads right from the comfort of your driveway. We’re available seven days a week and back our services with a 12-month, 12,000-mile warranty.
Contact us today for a hassle-free brake job you can trust!