How Much Do You Know About Car Braking Systems?

Steven Symes

What kind of brakes do you use a brake spoon on?

This tool is designed to fit in the opening at the back of the backing plates. Once it's in position, you can then use the spoon to change how much space there is between the brake shoes and the drum.

What is vapor lock?

When you're driving hard on a track, going down a steep mountain road or doing anything else where the temptation to ride the brakes a lot is there, you run the risk of vapor lock. A good way to avoid it is to downshift and use engine braking to slow the car.

On most vehicles, what is brake dust mostly made of?

As the cast iron brake rotor and pad rub against each other, most of the castoff is iron. Also in that unsightly black dust is carbon from the pads, plus fibers from the semi-metallic elements in the pads.

What does the brake master cylinder do?

When you press on the brake pedal, that's a mechanical force exerted by your foot. The master cylinder turns that into hydraulic pressure, which is ultimately what causes the brake calipers to press the pads against the rotors, slowing or stopping the vehicle.

What does ABS stand for?

Before ABS, when a driver slammed on the brakes the wheels would lock up, reducing or eliminating the ability to steer away from danger. This innovation essentially pumps the brakes for you, but better than humans can do it.

What's one of the main reasons automakers have cited for using electronic parking brakes in newer cars?

Automakers are always looking for ways to maximize space in vehicle interiors. Based on feedback from consumers, they feel that larger cupholders, somewhere to place your phone (other than the cupholder), and a big center console storage area are more important than a lever to engage the parking brake.

What are dimpled rotors typically used for, versus cross-drilled rotors?

Most people know about cross-drilled rotors, which are featured on lightweight sports cars, etc. Dimpled rotors also boost performance by allowing heat to escape quickly through the dimples, avoiding problems like vapor lock.

Which of the following is not a reason to buy new rotors instead of having them resurfaced?

Back in the day, resurfacing rotors made sense since they were expensive to replace, plus rotors were attached to the hub. Today, rotors are easy to take off, cost relatively little, and don't perform optimally once they've been resurfaced.

What are the two main advantages of two-piece rotors?

You also can just replace the disc ring instead of the hat as well. The only real drawback anyone can point out about two-piece rotors is that they cost significantly more, which is likely why you don't see them on many cars.

If your drum brakes have bell mouth, what must you do?

Bell mouth is when the drum has expanded out at the open end. That's not good, since it will reduce brake performance. This condition comes about when the brake drums thin out from normal wear, allowing the metal to warp.

Which of the following isn't a potential cause of pulsation when you press on the brake pedal?

Your brakes normally should feel smooth when you engage them, although pulsations could be the ABS at work in a panic stop or when you're on slippery ground. Aside from the other causes listed, warped hubs, worn wheel bearings and stiff CV joints can also be the source.

Where do hydro-boost brake boosters get their power from?

Instead of using a vacuum to create pressure for the brake booster, hydro-boost setups get their power from the hydraulic pressure of the power steering pump. This innovation was created to boost fuel efficiency.

What's one sign that your car's brake lines are worn out?

Inspecting your brake lines or having a technician do it is an excellent idea. Cracking, wet spots, chafing, loose mounts, a twisted hose, a brittle hose or a spongy hose are all signs it's time to swap them out for new ones.

What are brake pots?

Because the pistons or pots in the calipers are what force the pads against the rotors, they're vital to stopping performance. You'll notice big vehicles and performance cars have several pots per caliper for more braking pressure.

If brake rotors are slotted, which direction do the slots go?

As the brake pad and rotor rub against each other, that friction generates a ton of heat. You should know too much heat hurts performance, but slots cut into the rotors provide a quick way for that hot air to escape and flow away.

What is the alternative to bonded brake linings?

There are quite a few debates among car enthusiasts about which is better: bonded or riveted brake linings or pads. Some believe the rivets are more durable than adhesive used for bonded lining.

Which of the following is an advantage of carbon ceramic brake rotors?

Quite a few high-performance vehicles these days use carbon ceramic rotors, which don't deform as easily at high temperatures, won't corrode and weigh less.

How do you test a car's brake fluid to ensure it's not time to change it?

Brake fluid test kits, which usually come with quite a few tester strips, are available through most automotive parts stores and other retailers. It's a wise thing to do, because you want the brake fluid to not be corroding the brake lines from the inside out.

What do ABS accumulators always contain?

One of the vital components of an ABS system is the accumulator. There are integral accumulators that contain an electric pump, or non-integral setups with a spring-loaded design, both that provide pressure for the emergency brake pumping.

About how hot can brake rotors get as you drive normally on the street?

It might sound crazy, but your brake rotors get hot enough to cook a pizza, depending how much and how long you apply them. If you're driving aggressively, especially on a race track for lap after lap, your brakes can reach about 1,000 Fahrenheit.

What's the common cause of failure for cross drilled rotors?

While it depends on the material the rotors are made of, the manufacturing process and how you drive, cross drilled rotors have the notorious reputation of cracking. Once that happens, it's time to replace them.

As the brake pads wear down, what happens to the brake fluid level?

You should check the brake fluid level periodically on your car, ensuring it stays between the full and add markings. When you replace the pads, you might need to bleed the brakes slightly, because you can't let the fluid level sit above the full mark.

Where is the venting in a ventilated rotor?

With ventilated rotors, pathways between the two rotor faces, or the flat sides you see through the wheels, provide an expedited pathway for heat to escape from the rotor. The exact design of these pathways varies from brand to brand.

What causes the notorious brake pull?

You want the brakes on both sides of your car to match in force and performance. This is why your front brakes and rear brakes need to match each other exactly. If they don't for any reason, the car will pull to the side that exerts more braking force, which is called brake pull.

What kind of car brakes are self-energizing?

Drum brakes actually use the rotation of the wheel to apply one or both shoes against the inside of the drum, which creates friction and slows or stops the vehicle. The self-energizing function increases braking pressure for improved performance.

What kind of caliper mount design do most production vehicles have?

Floating calipers are attached to a pin that is fixed to the spindle. This design works better with the different OE manufacturing tolerances, which is why the vast majority of production vehicles feature this design.

Which of the following is a sign your brake lines might be leaking fluid?

Your brakes are a closed system, so if the brake fluid is constantly needing to be replenished, there's a leak. Brake lines are tough, but eventually they can give way to corrosion or be damaged in other ways, so you would need to replace them.

How does a dual master cylinder make your brakes safer?

If something were to happen to a brake line and it failed, whether through corrosion, damage in an accident or someone purposely cutting them, it would only mean one set of wheels would lose braking power, so you could still stop.

A brake combination valve will fill the role of all but which of the following devices?

Most cars that have front disc brakes and rear drum brakes also use a combination valve. Without this component working properly, your brakes won't function like they should.

The higher the DOT number for brake fluid, the higher something else is. What is it?

Most cars in the United States use either DOT 3 or Dot 4 brake fluid, which boil at 401 and 446 degrees Fahrenheit, respectively. These standards are set by the US Department of Transportation, or DOT.

Why would you use brake lubricants?

When you apply brake lubricant you absolutely need to stay away from any of the friction surfaces, like the rotors and pads. Lubricant will decrease friction, so apply it with extreme care.

What force is used to multiply the movement of the brake pedal?

Of course, the pressure you exert with the brake pedal isn't exactly what stops the car. The master cylinder takes that pressure and multiplies it, sending the result to the calipers through the lines using hydraulic force.

Why do some cars feature drum brakes in the rear?

The main reason for using drum brakes on the back wheels of cars is that they cost less. Drum brakes need less maintenance, which can also translate into savings, but they don't produce nearly as stellar of stopping performance, which is the trade-off.

What was the original application for disc brakes?

Because race cars push the limits, they need the best brakes possible. Disc brakes were invented as a big improvement over drum brakes. Over time, these were used on performance cars, and eventually are found on most cars today.

How do most emergency or parking brakes apply force to the rear wheels?

When you pull on a hand brake, you're tightening a steel cable that runs to the rear wheels. That actuates pads that either push against the drums or pinch the discs, keeping the car from rolling away.

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About This Quiz

Discs, drums, lines, master cylinders - to many people these are mysterious words and even more mysterious in their operation. It might as well be magic that brings their car to a halt, because they don't have the slightest idea how everything works. 

Most people just press on their brake pedal without a second thought, unless there's a problem. If you've ever pressed on the brake pedal and felt zero resistance, you know how that can make you panic in a hurry. Those kinds of situations are avoidable, if you care for your brake system and maintain it properly. If you're not like the average car owner, you know when you should do what with the brakes. You also might have a thorough understanding of the different components present in modern brake systems, plus how they operate.

You might even be one of those handy sorts who does your own brakes when it's time for them to be serviced. If you are, you'll ace this!

There's also emergency brakes, brake boosters, ABS, and so many other technologies involved in braking systems for cars. It's an exciting field, for the right person.

Just how much do you really know about braking systems for cars? Test your knowledge now to find out.

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