Your chemistry teacher failing you is scary, but your car brakes failing you is even scarier. So how do you prepare for brake failure? Well, exactly the same way you would prepare for a chemistry test -- study, practice and if you don’t know the answer, always pick choice C. Let’s learn about vehicle brake systems so that you’re ready to deal with brake failure if it happens to you.
Identifying Brake Failure
Staying ahead of brake failure is super important. Knowing what kind of braking performance is normal and what isn't can help you identify problems early and fix them before you end up in a dangerous situation. Your brake system has a lot of moving parts you need to keep an eye on. Parts like a disc or brake rotor, caliper, brake pads, brake fluid, wheel bearings, brake drums, hubs, wheel cylinders and more. Here's what you need to look out for when your brakes brake, erm, break.
- Screeching, rubbing or grinding noises: these are common signs that your brake pads need to be replaced because the lining is wearing down. Ignoring these signs could lead to more expensive repairs from damaged parts down the road (pun intended).
- Rumbling or shaking in your brake pedal or steering wheel: this is a sign that something is wrong with your rotors and that there is some metal on metal acting going on. Get to the shop asap to avoid further damage.
- A burning smell coming from your tires: this could be a sign of multiple issues. Typically it means two things are rubbing together that shouldn't be rubbing together causing unwanted friction. Get your car into the shop asap.
- Your brake warning light is on: you car is talking to you. Listen!
- Loss of stopping power when pushing the brake pedal: this can be caused by something called brake fade. Brake fade is caused by a buildup of heat and can affect both drum brake systems and disc braking systems causing your brakes to fail.
- Brake fluid on your tires: This means you have a leak in your brake line. Leaks in brake linings are no joke and will cause your brake fluid to slowly leak from your car. Your brake system relies on this fluid to operate, to be sure to get this fixed right away if you notice leaking fluid.
Brake-ing It Down
When brakes do their job right, it’s magical. How does pushing that little pedal make your 4,000-lb vehicle traveling at 75 mph come to a complete stop? Read on, curious learner.
“Under Pressure” is not only a catchy song by Queen and David Bowie, it’s also what happens when your foot hits the brake pedal. You see, you have a hydraulic brake, meaning when you press down on it, the force is multiplied by a hydraulic fluid (also called brake fluid) composed of mineral oil or water. Your car’s hydraulic fluid level needs to be in check in order for your brakes to work, so we’ll go over how to check it later in this article.
Hydraulic brakes aren’t the only “magic” that make cars stop. Friction plays an equally important role in the mechanics of your car brake. In fact, your brake contains parts that are composed of an anti-heat friction material, which helps create resistance and slow down your car. Let’s go over in more detail how hydraulic pressure and friction work together within your brake system.
Stranger than friction.
Most cars have two types of brakes: drum brakes and disc brakes. Hydraulic pressure and friction are at work in both types, but the mechanics of drum and disc brakes are slightly different.
In drum brakes, hydraulic fluid moves from the brake pedal to a set of “brake shoes,” which are composed of that friction material we mentioned earlier. The brake shoes then press up against the brake drum and bring your car wheels to a halt.
Diagram from HowStuffWorks.com
In disc brakes, brake fluid moves from the brake pedal to a brake caliper. The caliper contains two pads situated on either side of a brake rotor. When the brake pedal is activated, those pads get pressed together by a caliper piston. Scrrrrrrttt … and stop.
Diagram from HowStuffWorks.com
Disc brakes are considered to be better than drum brakes because they are less likely to get overheated, which can cause brake problems or brake failure. Typically, cars have disc brakes in the front and drum brakes in the back. In this way, your brake system is much like a mullet: business in the front, party in the back.
Phew. That was a lot of information about brakes. Now let’s take a break, shift gears and talk about what to do in the event of brake failure.
Can’t Stop, Won’t Stop
Brakes not braking? Step by step here’s what to do:
- If you drive a standard car, downshift to a lower gear. If you drive an automatic car, the gears will lower as you decelerate.
- If you have regular brakes, pump the brake pedal fast and hard to build up hydraulic brake fluid pressure. Hey, we talked about that earlier! If you have antilock brakes, push the brake all the way down and hold.
- Use your secret weapon: the emergency brake. Gradually apply the parking brake and be prepared for your car to skid.
- If all else fails, steer into a safe direction (like away from other cars) until your car rolls to a complete stop. If you’re driving super fast on the highway, that might mean you have to create friction between your car and the guardrail to slow down.
- Make sure you honk your horn and flash your warning lights to let other cars know that your brakes aren’t working! Above all, try to stay calm and remember your defensive driving techniques. You can do this.
You’ve learned that your brakes need hydraulic fluid to work properly. Here’s how to check and make sure your brake fluid levels are enough to quench your car’s thirst. Gotta keep that baby hydrated.
- Open up your car hood and locate the master cylinder. The top part of the master cylinder is a brake fluid reservoir that looks like this:
Don't drink this, please.
- Check the fluid level in the reservoir by making sure it’s between the marks labeled “max” and “min.”
- You can also check the color of your fluid. It should be brown, so if it looks black, that could mean you need to change it.
- Add brake fluid if necessary or visit the nearest auto mechanic.
The easiest way to prevent brake failure is to keep up your vehicle maintenance. Make sure you get an annual vehicle safety inspection and visit an auto shop if something feels “off” with your car. Regularly keep up with other preventative car maintenance like changing your oil, getting your tires rotated and replacing your windshield wipers and air filters. Make sure your car is nice and healthy so that you stay safe!