How do you check brake pad wear?
Brake pads are wear parts that lose thickness due to friction against the brake disc, which slows the vehicle. The normal thickness of brake pads is about 15 mm, with a minimum thickness of 3 mm. To check the wear of your brake pads, use a brake caliper.
Understanding how brakes work
A standard brake system consists of
- A brake disk: As the name suggests, this is a disk. It attaches to the wheel hub and rotates simultaneously with the wheel. Discs are usually made of iron or steel, and are sometimes drilled to improve the dissipation of heat from braking.
- A brake caliper with two pads inside: When the brake pedal is depressed, the caliper acts like a pair of pliers. It uses pistons to compress the pads on either side of the disc. This reduces the speed of the wheels and allows the car to slow down.
Unlike many other automotive components, brake rotors and pads do not have a specific number of miles before they need to be replaced. Why is that? Simply because their wear depends not only on the number of miles you drive, but also on your driving style. Certain driving styles wear out the tires more quickly than others. This is especially true of city driving, where the brakes are used very frequently.
How do I check brake pad wear?
Brake pads are subject to wear and should be replaced periodically, just like other brake components. This is due to the way brakes work: when you depress the brake pedal, brake fluid is pressurized and reaches the brake caliper.
The caliper contains the brake pads. The brake fluid presses the pads against the disk. The friction between the pads and the disc slows the rotation of the disc and thus the wheel. This is how your vehicle is braked, slowed, and brought to a stop.
However, these two elements also wear out due to the friction between the pads and the disk. Over time and with use, their thickness decreases. Brake pads lose material and become thinner until they no longer provide effective braking.
To check the wear of the brake pads, it is necessary to check their thickness. This requires removing the wheel to gain access to the brake system. Brake pad thickness is measured with a caliper, also known as a palmer.
Brake pads should be at least 3 mm thick. Generally, new pads are about 15 mm thick. However, be sure to check the manufacturer's wear rating, which can vary. This can be found in your owner's manual or in the RTA (Revue Technique Automobile) for your vehicle model.
Some vehicles have brake pad wear indicators. When your brake pads are worn out, a light comes on on your dashboard. It usually shows a circle surrounded by dotted brackets, symbolizing the brake pads.
What are the symptoms of worn pads?
The safest and most reliable way to check brake pad wear is to measure the thickness of the pads. However, worn brake pads can also cause a variety of symptoms:
- A loss of braking efficiency, which means longer stopping distances;
- Noise during braking;
- Vibration during braking, especially in the brake pedal;
- A soft brake pedal;
Visit your workshop immediately if you notice any of these symptoms. They indicate advanced brake pad wear, which is obviously dangerous on the road. Driving with worn brake pads puts your safety and the safety of others at risk because your braking ability will be less effective.
How can you protect your brake rotors and pads from wear?
Depending on your driving habits, brake pads and rotors wear differently. In addition to mileage and your driving style (sporty or not), it's important to know whether you drive more in town or on the highway. Whatever your situation, there are a number of tricks you can use to prolong the life of your brakes.
- Practice eco-driving: Smooth, quiet driving puts less stress on your braking system. By avoiding sudden and prolonged braking, eco-driving can help protect your brake pads and rotors from premature wear.
- Make more use of engine braking: Instead of slowing down by systematically using the brake pedal, you can use engine braking. In practice, this means letting go of the gas pedal, which automatically slows your engine. All you have to do is stop accelerating while you're driving.
- Downshifting: Using the vehicle's gear ratios allows you to adjust your speed while putting less pressure on the brakes.
- Looking ahead: This allows the driver to anticipate any braking maneuver at any time, thus reducing brake wear.
- Travel light: the lighter the car, the less pressure on the brakes.
- Regular maintenance: This allows the brakes to be repaired before they are too damaged or worn to become a problem.
When should you replace your brake pads?
Brake pads are wearing parts that should be replaced approximately every 30,000 kilometers. However, depending on how you use your vehicle, brake pad wear can vary. Brake pads that are used primarily in city driving, where braking is frequent, will wear out much faster.
Similarly, a sporty driving style that favors sudden, intense or harsh braking will wear the pads more quickly.
Finally, brake pad wear can also depend on the material used. Brake pads used to contain asbestos. The life of brake pads has been shortened because this dangerous material is no longer used.
Today, brake pads can be made of synthetic composite materials (cellulose, aramid, etc.), a mixture of synthetic materials and metal, ceramic, or metal. The life of these different types of pads is not the same: non-metallic pads wear out faster.
To ensure that you replace your brake pads on time without endangering your life, you should check the wear of your brake pads at every service or pre-service inspection. Stay within the manufacturer's recommended thickness to keep you driving safely.
Now you know how to check the wear of your brake pads! As you've probably realized, worn brake pads mean poorer braking performance, but it's important to avoid this. So check the thickness of your pads regularly and replace them if they are too worn.