Keeping an eye on your brake pads is important for ensuring that they are functioning the way that you need them too so that you can stop your vehicle easily and on time, every time. The thinner your brake pads get, the harder it's going to be for you to stop in an emergency and the more likely it is that you could get into an accident that harms you or others as a result. Obviously, you don't want that, so making sure your brake pads are in good working order is of vital importance to the overall functioning of your car.
There are a few ways that you can monitor your brake pads that don't necessarily involve a full brake inspection like you might get from a mechanic. There are simple things you can do right now to get an idea of how your brakes are performing.
Be Observant: The first indication you're ever going to get that you have an issue with your brake pads is how they feel and sound when you're using them. If you put your foot on the brakes to come to a stop and you hear a squealing sound, then that's a good indication your brakes have worn down considerably. This squealing sound is actually intentional, your brakes have a wear indicator installed in them that will make the sound as a warning when the pads have worn too thin.
You will also feel your brakes working differently when they start to wear down. When you put your foot on the brake pedal and it seems like the brakes aren't responding the way you expect, it's taking longer to come to a stop than normal, that's a good sign your pads have worn too thin. Additionally, you may be able to feel a pulse or vibration through your brake pedal into your foot.
Remove the Wheel: The most accurate way to measure your brake pads but the most complicated method as well is to actually physically remove each wheel and inspect the pads individually. In order to do this you're going to have to jack up the car and take the entire wheel off so it's a bit more in-depth and time-consuming than most people want, but it is the most accurate thing you can do. Plus, if you need to replace your brake pads, you're going to have to do this anyway.
If you’ve ever changed your tire, you at least know how to get started with this job by loosening the bolts and removing the wheel. Once you have the wheel off the rotor you can see the rotor and caliper itself. You'll be able to observe the brake pads through the hole in the caliper and should be able to measure both sides of your brake pads at this point. The easiest method of doing this involves using a compass to measure the width of the brake pad along with some calipers or a ruler to get a precise measurement.
Can You Check Brake Pads Without Removing the Wheel?
You can actually do a check of your brake pads without having to take the entire wheel off of your car. On most vehicles you can see the brake pads through the wheel itself, so you don't require any tools to remove it to get a better look at it. This isn't a thorough, highly engineered inspection by any means but it should be able to give you enough information that you can decide for yourself whether or not you need to do any work on your brakes or if the pad is in decent condition as it is.
Once you take a look through the wheel and locate where your brake pad is all you need to do is check for the thickness of it. Your brake pads should have a wear indicator to let you know if it's worn down to the point that actually needs to be replaced. This is a slot in the centre of the pad and if it's worn off completely then you know the pad will need to be replaced.
This is not true of every single vehicle on the road, and your make and model may require you to remove the wheel so that you can inspect the pad through the opening on the caliper. There would be a small area that you can look through like a window that gives you a cross-section of both the pad and the rotor. Just as with any other brake pad, if it looks worn down nearly completely, then you're going to need to have it replaced.
Use a Straw: If necessary, you can use a common drinking straw to get a rough estimate on how well your brake pads are doing. If you take a look through your wheel into the rotor and the brake caliper you should be able to get a view of the brake pad itself. This will look like a rubber lining on the inside of the caliper which is like a big clamp over the metal rotor behind your wheel.
Using a drinking straw, you can push the straw between the caliper on the rotor until it hits the brake disc and comes to a stop. With the straw firmly in place you can use a pen and mark the end of the brake pad on the straw. This will give you a decent if not entirely scientific idea of your brake pad thickness.
Measure the section of straw that you marked and then subtract 5 millimetres for the thickness of the brake pad backing plate. That will give you the rough number for how thick your brake pads are now.
What's a Good Thickness for a Brake Pad?
When you buy new brake pads you should be getting a thickness of around 10 mm to 13 millimetres. Under ideal conditions your brake pads should have a thickness of at least 6.4 mm or more to do their job properly. If your brake pads are thinner, such as 5 mm or 4mm they may still work but they're not going to be as good as they should be.
Most mechanics recommend that if your brake pads get down to about 3mm to 4mm they absolutely need to be replaced. 4 mm to 5 mm brake pads are at the outside edge of what you should be using. You wouldn't be faulted for replacing them at that thickness, but you could probably still get away with safe driving at that thickness for a time.
If your brake pads get down to about 2 mm you should have a metal wear indicator exposed at that point that will cause a squealing sound when you apply your brakes. This is a clear-cut indication that your brake pads absolutely need to be replaced and it would be dangerous to let them go any longer at that thickness.
How Long Should Brake Pads Last?
Brake pads work thanks to friction and that means they need to be constantly grinding against your wheels in order to do their job properly. Because your brake pads have to wear down if they're working the way they're intended to, they're going to have a limited lifespan no matter what. Science has yet to invent some kind of brake pad that's resistant to friction.
Generally, you can expect brake pads to last about 50,000 miles before they'll need to be replaced. That's an average number and by no means is set in stone. Some brake pads will likely need to be replaced after 25,000 miles and some can last 70,000 miles or longer. To know for sure how long you can expect your brake pads to last you're going to have to check with your owner's manual and also factor in the kind of brake pads you may have on your vehicle. If they are factory brake pads, then your owner's manual can give you the best idea but if you've picked up some aftermarket brake pads after the fact, you'll need to know the intended lifespan of those.
Regardless of what was written on paper as a lifespan for your brake pads there's no accounting for real-world conditions. If you do a lot of driving and push your vehicle to the limits which includes a lot of hard braking, or maybe you drive in extreme weather conditions that are going to put extra strain on your brake pads then you can expect they will probably wear down a little bit sooner than later. Still, this gives you a general idea of what you can expect in terms of how long brake pads last.
Signs and Symptoms of Bad Brake Pads
Although routine maintenance and observation of your brake pads never hurts, you're likely only going to check your brake pads if there's something that gives you a reason to do so. With that in mind, if you notice any of these symptoms of bad brakes, you're going to want to take a look and see what's going on.
The Brake Light is On
This one is obvious but if you have a red or yellow brake warning light that comes on your dashboard then it means that it's time for you to have your brakes inspected. It's possible the light just came on to indicate a problem as well. That may be something as simple as the parking brake is still on. However, if that's not the case, then you do want to take a look at your brakes to see what's going on.
Your brakes may overheat if the pads are worn too thin and produce a burning kind of chemical smell, especially if you brake hard or on a steep hill of some kind. If you notice a smell like this when you're braking, it's a good idea to pull over right away just to be safe. Give your brakes a quick inspection from outside and give them a chance to cool down. If they heat up too much the brake fluid could boil and your brakes can fail entirely.
When your brake pads are worn down far enough then you're not going to have the amount of friction you need to brake promptly. That means that when you put your foot on the brake pedal it's going to take you a few moments to come to a complete stop.
As we mentioned earlier, if you put your foot on the brake pedal and the response in your foot feels kind of soft or spongy that's a good sign that you have a problem with your brake pads being worn down. The brakes will still respond but it feels like you have to press harder on the brake pedal to get them to work.
Swerving When Braking
If you feel the vehicle pulling to one side or another when you apply the brakes then that's an indication that you have uneven brakes, likely meaning that one of your pads is more worn out than the other one. When this happens, the brakes on one side will apply more firmly than on the other side. This could also be a problem with calipers, brake fluid, or tire wear, but the pads could definitely be responsible.
We mentioned this earlier as well, but bad brake pads tend to create a variety of noises that can include squealing, grinding, and squeaking sounds. This could be from the brakes being worn down so far that that little bit of metal inside that's meant to warn you that they're worn down is grinding against your rotor or it could be because you have dust accumulated inside the pad as well.
The Bottom Line
One of the scariest things that can happen to a driver is to realize that their brakes are not working the way that they're supposed to. No one wants to experience brake failure. The potential for damage to your vehicle, for injury to yourself and others is extremely high. For that reason, you want to make sure you're paying attention to the health of your brakes and your brake pads as much as you can. Keep in mind when you need to take them in for routine maintenance and remember to give them a quick visual inspection every so often, especially if you notice any of the symptoms we mentioned for bad brakes.