What Is Brake Fluid Used For?


When I was reading some articles on the internet in efforts to come up with a list of essentials for my car repair kit, I came across brake fluid throughout my search. Since I hadn’t really heard much about this substance before, I decided to look into the topic more in order to find out exactly what brake fluid is used for. 

What is brake fluid used for? Brake fluid is contained within the components of the braking system in a car, and is used to shift weight throughout all of the individual areas to exert pressure as needed. The pressure and force that is given off by the brake fluid causes the brakes to kick in and bring the wheels of the vehicle to a complete stop from the inside. 

If you have ever owned a car or driven at all, you have probably heard of brake fluid at one point or another. While this is just a small component of all of the complex systems within a car, it does not prove to be any less important. 

Brake fluid serves a lot of purposes when it is working on the interior of a car’s braking system. This includes shifting and controlling pressure, maintaining the quality of the brakes, and many more. Keep reading to find out everything you need to know about brake fluid and its uses. 

What Is Brake Fluid Used For?

When you hear the term brake fluid, it might seem like the two words that are strung together have no relation to each other. After all, what would a fluid be doing inside of the brakes of a car, right?

The braking system in an automobile actually uses brake fluid as a vital component of its functions. In fact, it is so essential that without it, the driver would not be able to bring the car to a stop after pushing on the brake pedal. 

The importance of this substance will be discussed in later sections, but for now, we will be talking about how brake fluid is used in these circumstances. 

Take a look at the list below for a general idea of uses for brake fluid, followed by a more detailed explanation below. 

Brake Fluid Uses:

  • Transfer pressure through different components within the braking system 
  • Lubricates the individual parts inside of the brakes
  • Prevents corrosion within the braking system 

The first and most commonly recognized use for brake fluid in a car’s braking system is to transfer pressure through difference components within the braking system. The process begins when the driver pushes on the brakes, and the fluid is essentially released and begins to move through the targeted areas of the brakes. 

In addition to the process that brake fluid goes through in order to navigate the braking system and assist the wheels in coming to a complete stop, which we will also discuss in later sections, it can also offer a few unexpected benefits along with these ones. 

Most people don’t realize that brake fluid is actually a multi-tasking substance. In other words, you use it for one essential purpose, and it will help you out in other ways at the same time. 

Along with contributing to the function of the actual braking system, brake fluid can serve to lubricate all of the individual parts inside of the brakes. This will not require a separate application of the fluid, it will transfer to the other components on its own. 

Similarly, the presence of the brake fluid inside of the braking system will also prevent corrosion. This is something that commonly occurs within automobiles and can be a headache to fix when it does. 

Luckily, you will have a very good chance of staying away from these issues when you use brake fluid properly and regularly. 

How Does Brake Fluid Work Inside A Braking System?

Now that we have gone over what braking fluid can be used for, we will switch over to the topic of how it actually works when it is inside of the braking system. 

How Brake Fluid Works:

  1. The driver begins the process by intending to stop the car and pushing on the brake pedal 
  2. The pressure on the brakes pushes up against the piston (inside of the brake’s caliper) and compresses it 
  3. The pressure inside of the brake lines begins to increase, and releases the brake fluid into the braking system 
  4. The brake fluid moves along the components and applies pressure to the rotors
  5. The rotors are forced to put pressure onto the brake pads (from the brake fluid) 
  6. The friction that is caused between the rotor and brake pads causes the wheels to stop on the outside of the car

The process of brake fluid in action will begin when the driver decides that they need to stop the car, and consequently pushes on the brake pedal. The pressure that is put onto the brakes then pushes up against the piston. 

The piston is located within the brake’s caliper, and is compressed by the force that is exerted by the brake pedal. 

As a result of this action, the pressure inside of the brake lines will begin to increase to very high levels, finally releasing the brake fluid into the braking system. 

The fluid will then start to move along the path of the braking system, through each individual component until it reaches the rotors. The weight of the fluid will apply pressure to the rotor components, forcing them to put pressure onto the brake pads. 

When the rotors are pushed by the brake fluid into the pads, the two materials will come in close contact with each other, creating friction between them. This friction that is created will transfer to the wheels of the car until they come to a complete stop. 

The Characteristics Of Brake Fluid 

With all of the helpful properties that come with brake fluid, it is not uncommon to wonder how all of this is possible with the use of just one simple liquid. In this section, we will be covering the characteristics of brake fluid that allow it to be able to carry out all of the functions that have been mentioned previously in this article. 

Brake Fluid Characteristics:

  • Liquid material 
  • Non-compressible (cannot be compressed or altered) 
  • Has a definite weight 
  • Will always keep the same weight, and be able to exert it as needed
  • Can flow freely to the targeted destination with the braking system 
  • Thick material that is resistant to changing temperatures 

As we know, brake fluid is a liquid material, and it is also non-compressible, meaning that it cannot be compressed or altered when it is moved about the braking system. 

In addition, it has a definite weight that will stay the same throughout most of its time within the brakes. This weight is able to be exerted on any component inside of the braking system at any moment, but the other pieces cannot do the same to the liquid, making it very versatile. 

Another advantage of this type of material is that it can flow freely to the targeted destination within the braking system, since it is a liquid instead of a solid. 

Most brake fluids are made of a thick material that is resistant to changing temperatures, meaning that no matter how hot or cold the car’s engine and braking systems get, the brake fluid will remain intact without boiling or freezing. 

As you can see, brake fluid can be used for more than one purpose, but will ultimately serve to keep the brakes in your car working as well as maintain all of the individual components within the system. 

Arwood

I'm Arwood, but the grandkids call me Big Papa. After retiring from teaching automotive classes for 30+ years I decided to create a blog about all the questions I used to get about brakes and anything automotive.

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