Obviously brakes are important, but important does not mean complex. Many people take a hands-off approach to brakes and take the word of any mechanic or dealership flunky as gospel. The only rule for how long brake pads will last is this: There are no rules. How often you need to change your brake pads varies based on your driving style, the type of driving you do, the weight of your vehicle, the quality of the brake pads, and the condition of your brake rotors.
Obviously, if you drive aggressively (tailgate others, hard brake at stoplights, etc.) you will use the brakes more often and wear them out quicker than normal. If you drive in a hilly area or in constant stop and go traffic, you will use the brakes more often and wear them out quicker than normal. Getting the picture?
So, how can you know if you need change your pads? You could take your car into one of the infinite number of shops that offer free brake inspections. Unfortunately, if that shop is even a little less than honest, they will tell you that you need new pads. If you own a BMW or other vehicle from a small selection of German automakers, then your brake pads have an electronic monitor built in. When the pads wear down, a light will display on your dashboard.
Even if you own a Cavalier, you’re still in luck. Almost all brake pads come with a built in wear indicator! This usually consists of a small metal tab on the brake pad. As the pad wears down, this tab comes closer to the brake rotor. When it finally makes contact, you will hear a slight screeching or scraping sound.
Once you hear the scrape, it’s time to change the pads. You don’t have to do it the same day, but try not to let it go too long. If the scraping turns into a rough grinding sound, you need to change those pads now! Running the pads too low can cause damage to your rotors. This causes your brakes to be less effective and could cost you more money in the end.
Always replace the brake shoes in sets. Replace all four front pads/shoes at a time. Never replace brake pad/shoes on one wheel only.
Just as your gas mileage will vary depending on where and how you drive, so it goes with the life of brake pads (or linings), the friction material that gets pressed against a metal disc or drum to stop your vehicle.
If you drive only 8,000 miles a year but it’s mainly in a crowded urban area such as Chicago, Boston or Washington, D.C., you will need to replace brake pads more often than someone who drives 28,000 miles a year across the flatlands of Nebraska. You use your brakes a lot more in urban driving than on a rural highway.
Unfortunately, there is no clear-cut schedule that tells you when it’s time to replace the brakes, so you need to rely on your ears and the advice of an experienced automotive technician. Most vehicles should have their tires rotated at least every six months, and that is a good time to have the brakes inspected, as well. A mechanic can check the thickness of the pads and the condition of the brake hardware to spot wear.
Many cars have built-in wear sensors that scrape against a brake disc when the linings needed replacing. The driver will hear an annoying screeching sound when they apply the brakes (or when the brakes are released on some vehicles).
Those sensors aren’t on every vehicle, so drivers should listen for squeaks, squeals, grinding (often a sign that brake pads are entirely gone) and other noises that indicate wear. Some minor noises can be eliminated by cleaning the brakes, but persistent, prominent noises usually mean parts are worn. Other signs are pulsations through the brake pedal, longer stopping distances, or when you apply the brakes your foot goes down further, closer to the floor. Because brake linings wear gradually, you may not notice the demise in performance, so that’s where the experienced eye of a mechanic can help.
All cars have a brake warning light that comes on for a few seconds every time you start your car. If it comes on while driving, that probably means your brake system is low on fluid because of a leak or a problem with the brake master cylinder. Note that this is not the same warning light that comes on when you apply the hand- or foot-operated parking brake.
All cars and light trucks also have front disc brakes. Most have rear discs, as well, though some lower-priced cars still come with rear drum brakes. With discs, it has been common practice to just replace the brake pads and resurface the rotors on a lathe if needed so the surface is even and smooth.
In recent years, however, more automakers have switched to rotors that are lighter and thinner to reduce weight and save money. Discs used to last through two or three resurfacings, but don’t be surprised if when it’s time to replace the pads you’re told you also need new rotors. The current ones may not have enough material to be shaved off in resurfacing and may not be as durable as those from, say, 10 or more years ago. In addition, repair shops are reluctant to resurface rotors because it adds time to a job and the quality of the work can vary by who does it and how good they are. Instead, it is faster, easier and more profitable for repair shops to just install new rotors along with new pads.