by Sam Dillinger (comments: 0)

Brake System Basics

brake system basics

Other than being able to get you to where you're going, the most important function of your car is to be able to stop before you hit anything when you arrive! We’re going to take a look at some of the important things to know about your braking system as an every day driver. We’ll start by looking at the mechanical side of the brakes, and then take a peak at the hydraulic side of the equation. The more well informed you are about how something works, the better you can use it!

On every vehicle manufactured for sale in the modern automotive market, disc brakes are standard equipment. Beginning with the Crosley, manufactured in Indiana in 1949, disc brakes have proven to be the most reliable and safest way to stop our cars and trucks. It was much later on that vehicles went to 4 wheel disc brake systems, but now that’s the way all cars are made. The system uses hydraulic clamping force to stop the vehicle by “pinching” the rotor, or disc. The brake pads ride directly on the rotor and even the slightest pressure from your foot on the brake pedal will start to apply stopping force. Quick fact about applying the brakes: the front brakes apply before the rear brakes do, which lends to why the front brakes need to be replaced more often than the rear. The full mechanical side consists of: you (you’re the way the process starts after all), the brake pedal, the master cylinder, the brake fluid lines, the brake calipers, the brake pads, and the rotors are last in the line. In the middle of the hydraulic flow from the master cylinder to the brake rotors is where the ABS system lives. In our next article, we’ll be going over how the ABS system works, and what it does for you.

For the hydraulic part of the system, we’ve got all the parts that are in the mechanical section. The 2 systems operate in tandem, but in different manners. The brake fluid is directed by a piston in the master cylinder to the rotors through the brake lines. For those of you who don’t know, the reason we use a hydraulic system overlaid on the mechanical system of the brakes is based on a very simple concept- you can't compress a liquid. No matter how hard you squeeze it, a fluid will push back equally as hard or travel in the direction of the least resistance. By using this principle, you get a system that’s sealed off from outside contaminants (well when everything is working correctly it’s sealed anyway), and it responds instantly to your input, making your control over the stopping function as real-time as it’s possible to be. You can see the safety advantage in having no lag in the stopping force being instantly available!

The biggest enemy to the components of your braking system is heat. This is actually the biggest enemy of all of the systems on your vehicle, especially since it actually generates a tremendous amount of heat on it’s own. We’ll be taking a further look at the way heat effects the vehicle as a whole in a later article. For your braking system in particular- heat will accelerate wear of the brake pads, cause the rotors to warp, and in extreme (it should be noted that I mean VERY extreme conditions, that most of us aren’t likely to ever face) the heat could boil your brake fluid. If you induce air into the hydraulic system anywhere, it will make the brake pedal have a “spongy” or “soft” feeling and will severely decrease the braking ability of the car.

It’s really important to make sure you monitor the level of the brake fluid and also to watch for the red brake light on the dash. This light is a direct indicator of the level of the brake fluid in the master cylinder. The light can also be an indicator of the brake pads being worn. The brake fluid level will drop as the brake pads wear, and if they get low enough at all 4 wheels, the brake fluid light will start to come on when your slowing down, or even be on all the time.

When the brake rotors warp, there will be a pulsing feeling in the brake pedal when you push it. This pulsing can get quite severe and effect the ability of your vehicle to stop in the most efficient manner. If you notice this sensation, you need to either have the rotors resurfaced or replaced. If you're going to be doing the work yourself, I recommend just replacing the rotors. It’s become quite cost efficient, and then you have a brand new rotor, instead of the old one that now has less overall mass.

There is so much more information available for any of the systems I've mentioned here, I’m keeping this article to just the basics, to give you the most important aspects that you need to know. If you have further questions or concerns, and if you're looking for advice, make sure to visit us at www.mycheckenginelight.net!

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Meet Sam Dillinger

My name is Sam Dillinger. I've been a professional, dealership technician for 18 and a half years. My first introduction to mechanical repair was when my own vehicle broke down in the fall of 1995. I was 18 and couldn't afford to pay to have it fixed. So I borrowed tools and asked a ton of questions and, eventually, was able to replace the clutch on my truck by myself. During the course of that project, I found that I really enjoyed having a wrench in my hand and figuring out the puzzle of disassembly and reassembly of a motor vehicle.

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