Your vehicle isn’t much good to you if it doesn’t go when it’s supposed to, but you’d probably agree it’s equally important that it stop when it’s supposed to as well. And that means brakes that work. The braking system in your vehicle has several components, all of which play a crucial role. When any of these parts start having issues, there are warning signs to help you diagnose what might be causing the problem.
When it comes to failing components, brake pads are often the problem, and they’re particularly important for two reasons. First, worn out brake pads have heated up and cooled down so many times that the friction material isn’t able to stop your vehicle as effectively as it should. Secondly, thin pads don’t adequately insulate the brake fluid, caliper, caliper piston, brake lines and hoses from the intense heat of braking, so those items are likely to go bad more quickly.
It’s also worth noting that typically, brake components wear out symmetrically. That means if you’re having to replace a component on one side of the vehicle, it’s likely the other side will go bad soon as well, which is why it’s a good idea (except in unusual circumstances) to replace brake components in pairs.
All that being said, here are some of the most common symptoms of brake component failure, and the underlying issues that could cause them.
Squealing When Braking
Believe it or not, most brake pads are made with a wear indicator known as a “squealer”. It’s a piece of softer metal designed to make contact with the brake rotor and make a squealing sound when the pad is worn down. Most brake pads will last forty thousand miles or more under normal conditions (though there are some ceramic formulations that can last up to seventy-five thousand miles). Once the friction surface of your brake pads has worn down to the point they should be replaced—about one-sixteenth of an inch—you should start hearing the squealer.
Grinding When Braking
In many cases, if you hear grinding when you brake, you’ve waited far too long to change your brake pads. Grinding can be a sign that the friction material intended to stop your vehicle has worn down completely, and what’s left is the metal backing plate. This will also cause irreparable damage to your rotors.
It is possible to hear a grinding-type sound that isn’t serious. If your rotors have been damp for any reason and you haven’t driven for a day or two, rust may form that can create noise the first few times you brake. Your brake pads should take that rust off the surface of the rotors after several stops, so it isn’t cause for concern unless the rust persists beyond a short period of normal driving.
Steering Pulls to One Side When Braking
You should never have to adjust your steering one way or the other when you brake. If your vehicle pulls to one side when you’re braking, it’s evidence the brake system on one side is working more effectively than the other. It’s possible you have hardware that’s frozen or sticking, or a caliper that’s going bad.
As stated above, it’s important to remember if you find it necessary to replace a stuck caliper or hardware, it’s a good idea to change that same component on the other side as well. If you only change the one side, it’s possible you could wind up with a vehicle that pulls the other direction when you brake.
Steering Wheel Vibrates When Braking
You shouldn’t feel anything in your steering wheel when you brake. If you get vibration while braking, it’s likely your rotors are warped—that is, not completely flat like they should be—and need to be turned or replaced. It’s difficult to see without a dial indicator or brake lathe, and your brake pads probably won’t be showing abnormal wear either, so it may be necessary to have the rotors inspected by a professional. Most O’Reilly Auto Parts stores can measure rotors (and/or brake drums) and resurface them if they fall within certain specifications and aren’t showing signs of extreme wear.
Brake Pedal Feels Soft/Goes to the Floor
A soft brake pedal can be an intermittent symptom. Your vehicle may stop like normal at times, but at other times, you may have to push the pedal all the way to the floorboard. When the pedal does go to the floor, it could go immediately or slowly while you’re at a stop.
One possibility—if you’ve recently had brake work done—is that the brake system has gotten air trapped in it. If so, the brakes could feel spongy, and the system just needs to be bled. If you haven’t had any recent brake repairs, the most likely problem is a leak. Check the brake fluid level in the master cylinder reservoir first (if there’s no leak, the reservoir should still be full), then look for fluid leaks or wet spots on or under your hoses and lines, calipers and wheel cylinders. It’s also not uncommon to find a leak at the back of the master cylinder where it attaches to the power brake booster.
Brake Pedal Feels Hard/Requires More Pressure
This is most likely a problem with the vacuum-assisted or power brake system that is designed to make braking easier. The brake booster is a component that acts as a vacuum storage container. It adds power to the brake pressure you apply with the pedal, and there are two common types of failure. The first is a hole in the vacuum diaphragm, and the second is a blocked vacuum hose or line. In some cases the intake can become clogged by carbon buildup, and in other cases you’ll find a collapsed hose. These issues will affect the vacuum needed to assist in braking power, and require more brake pedal pressure from the driver. In extreme circumstances, a vacuum leak from a hose or the power brake booster can cause the engine RPMs to rise or fall, which can lead to stalling when you brake.
Dashboard Brake Lights
The brake warning lights on your instrument panel will be either yellow or red, and if one of them comes on and stays on, it requires immediate attention. A dash light doesn’t mean your vehicle won’t stop when you brake, but there’s likely an issue that could become a much bigger problem if it isn’t taken care of. The yellow light typically indicates an issue with the ABS (Anti-lock Braking System), and can be the most difficult to diagnose. The red light can indicate low brake fluid or could come as a result of an electronic wear sensor.
An electronic wear sensor is a feature in some vehicles as opposed to the “squealers” mentioned above. This sensor is a wire embedded in the friction material of the brake pad itself (or installed separately) that will trigger a warning light when the pads get worn down to the point where they need to be replaced.
If you’ve noticed any of these symptoms and need replacement parts or step-by-step instructions on how to make the needed repairs, take a look around our How-To Hub page. Anything you need for your do-it-yourself brake repair is available at your local O’Reilly Auto Parts store or OReillyAuto.com.
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