How does your brake system work?

STOP....collaborate and listen (sorry y'all I had to)

Your brake system from foot to stop

Coming up to a redlight, time to slow down. You move your foot to the brake pedal and start applying pressure. How does one little foot stop a 2-ton hunk of machinery?With a lot of help.

Let’s take a look at the pieces of the brake system and discuss how they work together to keep you off your windshield.

Brake Pedal and Booster

The first piece of the puzzle is your brake pedal. It’s a piece of metal with a footpad on it. You step on it. Fun.

Touching the pedal is a stop lamp switch- a small plunger that releases as you touch the pedal, and tells your brake lights to come on.

The force of the brake pedal pushes in the rod of your brake booster, which sticks through your firewall, into the engine bay and the backside of your booster.

While there are a few different ways of accomplishing added brake boost, the most common kind by far is a vacuum brake booster.

These have a diaphragm inside of a metal shell. On one side of the diaphragm is vacuum pressure from whatever source your car uses (typically the engine intake or vacuum pump.)

When you press the pedal and it moves the cylinders inside, atmospheric pressure is released into the opposite side of the bladder, which pushes the vacuum pressure and forces a rod to push into your master cylinder.

Master Cylinder and Brake Lines

Think of the master cylinder as the heart of your brake system. Your master cylinder creates pressure by forcing brake fluid into the rest of the system. The same amount(or more) of pressure in the system carries out to the other parts of the brake system through lines.

Brake lines are basically hollow metal pipes, or rubber hoses, that carry brake fluid between all the parts of your system. Think of them as blood vessels. If one leaks, you have problems.

Assuming they are drier than my humor, now pressurized brake fluid moves its way to the ABS unit

Anti-lock Brake System (ABS) Unit

The ABS unit has a series of valves that open and close as needed to redistribute braking power when the car’s computer (Read About That Here) realizes, via a signal from the wheel speed sensors, that one tire is losing traction. Under normal conditions, fluid pressure flows freely through to the calipers.

Calipers, Brake Pads, and Rotors Oh My!

The brake calipers sit just inside of your wheels, on the rotors. It’s just a claw basically, that slowly squeezes together the brake pads as it is pressurized.

The brake pads, which sit one on each side of the rotor, sandwiched in the caliper, create friction as they try to stop the rotor from spinning.

The rotor is attached to the hub, which is attached to the wheel and tire. As friction from the brake pads slows its spin, your wheels slow and you’ve finally come to a stop.

OK GreaseMonkey, wrap it up

So now you can go on a long-winded explanation of how a brake system works when Todd from accounting asks you what you learned this week because he’s playing office politics and wants to feel smarter than you.

Jokes on you Todd. They have a GreaseMonkey stuffing this knowledge into their brain. Get rekt.

It’s pretty amazing to think of how flawlessly this system allows you to stop an entire vehicle by lightly pushing your foot down. All this happens every time you touch your brake pedal.

The brake system has the most important job in the whole car. Keeping you safe most frequently. It’s wise to check the system over every oil change or so, to make sure the pads aren’t worn and no leaks are present.

If you notice your brakes getting harder or softer than usual, you should get it figured out ASAP. Squealing as you come to a stop is a sign of brake pads getting low. Listen out and feel for these things to hopefully catch problems before total failure.

If you have any questions or concerns, comment below, or shoot me a tweet or DM @BowTiedGreaseMonkey on Twitter.

Don’t forget to ask if there are specific topics you’d like me to cover. The goal of this is to teach you all more about your vehicles. Your interests matter.

See y’all next time.

Love,

Your favorite primate