What does brake fluid do?

Accelerating and braking are simple actions that are repeated countless times when you're behind the wheel of your car. However, braking is a sensitive area that should not be taken lightly.

When you're behind the wheel, an efficient braking system is the key to a safe and smooth ride.

However, in order to maintain good braking conditions, drivers must ensure that the various components of their braking system are in good condition, starting with the brake fluid, which is an essential component. But what is brake fluid? What is it used for?

In this article, we'll answer all these questions, so you'll no longer have to wonder about your car's brake fluid.

Brake fluid: how it works

Brake fluid is a member of your car's fluid family. As its name suggests, it is used to brake your car, so it plays a vital role in the braking system (rotors, pads, drum brakes, etc.).

It is hygroscopic (absorbs moisture from the air) and incompressible. These two properties are essential because they allow the brake fluid to be compressed by the master cylinder when the brake pedal is depressed. It is the compression of this fluid that exerts a force on the caliper pistons, which in turn push the brake pads against the rotors (or shoes for drum brakes), creating friction that slows the wheel speed and thus slows the car.

Brake fluid is essential to the braking process of your vehicle. It transmits braking force to all four wheels, slowing and stopping them.

Where is the brake fluid located?

The brake fluid reservoir is located on the master cylinder in the engine compartment, often on the driver's side. It's made of plastic, and you'll see low and high indicators on it, which you can use to top off if necessary. You can access it by lifting the hood: it's on top of the engine. You'll recognize the brake fluid reservoir by its cap, whose symbol is a circle surrounded by brackets: this is the brake logo.

Which brake fluid should I choose for my car?

There are several categories of brake fluids with different specifications. To make sure you choose the right brake fluid for your car, consult the owner's manual.

There are several categories of brake fluid:

• Silicone fluids are used primarily for military vehicles because they don't hold water and protect the system from rust.
• Synthetic fluids are used on other vehicles.

Refer to your vehicle manufacturer's manual for the type of fluid best suited for your vehicle. DOT (Department Of Transportation) certification corresponds to the heat resistance of the fluid:

• DOT 3: This fluid is generally used for vehicles equipped with drum brakes. This is the least expensive brake fluid on the market. However, it is not suitable for all applications. Because its boiling point is reached more easily (205° in dry weather), it is not at all suitable for sports use.
• DOT 4: With a boiling point of 230° in dry weather, this is the most commonly used brake fluid in cars because it offers the best value for money. It is suitable for most applications.
• DOT 5.1: This fluid is best suited for sports cars with large diameter rotor brakes. What's more, it boils at 260° in dry weather, making it an excellent choice for track use.

Good to know: You can't mix different types of brake fluids. In fact, it's a bad idea to mix DOT 3 brake fluid with DOT 5.1 because, as mentioned above, they don't have the same boiling point. Doing so could damage your brake system.

How much does brake fluid cost?

The price of a can of brake fluid varies from $4 to $20, depending on the brand and type of fluid. We recommend that you compare prices carefully before purchasing a can. If you need to bleed your brake fluid, expect to pay an average of $60.  As you can see, it's important to take care of your brake fluid to ensure the smooth operation of your brake system and your vehicle.