Whether it's the daily commute or a long-distance drive, your brake pads are bound to get a good workout. After all, they're tasked with using the power of friction to bring your car to a safe and controlled stop. Needless to say, they're bound to wear out sooner or later. Knowing when it's time to change your brake pads not only helps keep your brake system in great shape, but it also keeps you and your fellow motorists safe.
Visually Checking Brake Pad Thickness
One telltale sign that it's time to replace your brake pads is when the pads become significantly worn. Most brake pads come with a 1/2-inch (or approximately 12.7 millimeters) of friction material out of the box. Once they're put into action, they continuously shed friction material every time you apply the brakes. Sooner or later, your pads will reach a thickness of 1/8-inch (or approximately 3.17 millimeters), which is usually when most mechanics recommend replacing them with a brand-new set.
Depending on your vehicle's wheel design, you could eyeball the thickness of the pads without removing the wheel. However, it's easy for the caliper hardware to block a clear view of your pads. In addition, most people aren't experts at gauging pad thickness just by a naked-eye observation.
For a more accurate observation, you're better off putting your vehicle on jack stands and removing the wheel. Once the wheel's off, you can use a compass and a ruler to measure the brake pad thickness. Simply place the compass's two points on each edge of the brake pad and lock the compass in place. Then you can use your ruler to measure the thickness and determine whether or not you'll need new brake pads.
Keeping an Ear Out for Trouble
A simpler way of knowing when to change your brake pads is to simply listen for the wear indicator. The wear indicator is a simple metal tab that protrudes from one end of the brake pad. As the brake pad wears down, the wear brings the tab closer to the brake rotor surface. Once the brake pad reaches its minimum thickness, the tab finally comes into contact with the rotor.
Once the tab hits the rotor, it makes a telltale screeching sound that varies in intensity depending on the amount of wear. This means that the faint singing that comes with initial contact could quickly transform into a harsh grinding noise as the tab digs deeper into the rotor. The tab also etches score lines into the rotor, meaning that you may have to resurface or even replace the rotor if you don't have the pads replaced on time.
Counting the Mileage
You can also use your vehicle's own mileage to keep tabs on your brake pads. Most pads offer 30,000 to 70,000 miles of useful life for most vehicle applications. However, this depends on a variety of factors, including
- The type of brake pad compound used on your braking system
- Driving habits, such as frequent stop-and-go driving, late braking and "riding the brakes"
- Other mechanical issues with your brake system including malfunctioning calipers and pistons
It's always a good idea to note the vehicle mileage prior to installing your brake pads. Then you can estimate the mileage at when you may need to replace the pads. For instance, if your car has 150,000 miles and you recently installed a fresh set of brake pads designed to last a minimum of 30,000 miles, then you'll need to change your brake pads at 180,000 miles.
The above can help you figure out when it's time to swap your old, worn brake pads with a fresher and safer set. Don't forget that you can always have your trusted mechanic take a look at your brakes and determine if and when the pads should be changed. Click here for more info about having your brakes checked.