A Complete Guide to Brake Fluid

Published on

July 8, 2024

Brake fluid reservoir of brake system in the car

As drivers, we take braking for granted. But little do we know how complex the braking system really is and all the key components that help bring our vehicles to a complete stop. One of the most important parts of the braking system is the fluid that runs through it. In this post, we'll cover all things brake fluid.

What is Brake Fluid?

What is brake fluid? As the name implies, it's fluid that's designed to help bring your vehicle to a complete stop. More specifically, it helps convert pedal force into stopping pressure every time you press down on the brake pedal. Of all the fluids that help your vehicle tick, brake fluid is among the most important - especially when it comes to safety.

What Does Brake Fluid Do & How Does it Work?

If your vehicle didn't have brake fluid, it would take an awful lot of force for you to stop your vehicle - much more force than just gently pushing the brake pedal. That's the main function of brake fluid - it helps to amplify the force that's placed on the brake pedal and convert it into the necessary pressure to activate the brakes to stop your vehicle. The harder you press your brakes, the more pressurized the fluid becomes, which thereby helps dictate how fast or how slow you stop.

However, brake fluid must be formulated right for it to work effectively. That's why it's important to ensure that it's changed out per manufacturer recommendations. Bad or aging brake fluid is going to impact braking performance.

Common Types of Brake Fluid

Contrary to what you might think, there's more than just one type of brake fluid. Two of the most popular types of brake fluid are glycol-based fluid and silicone-based fluid.

Glycol-based fluid comes in various types of subcategories, such as DOT 3 and DOT 4. DOT 3 is the most common and suitable for just about every vehicle. DOT 4 is an enhanced version of DOT 3, ideal for performance in more extreme conditions.

Silicone-based brake fluid tends to have a higher boiling point, they’re ideal for vehicles that endure high thermal stress. These vehicles may include sports cars and heavy-duty vehicles.

How to Tell if Your Brake Fluid is Low

Just as it's important to change the brake fluid in your vehicle per manufacturer recommendations, you also want to ensure that your fluid is always at healthy levels. So how can you tell if your brake fluid is low? Here are some tell-tale signs:

  • The brake pedal feels soft: If it seems like you have to press down further on your pedal to engage the brake, it's often a sign of low fluid.
  • There's puddling beneath the vehicle: If you spot puddles underneath the front of your vehicle when it's parked, check to see if it's brake fluid. Brake fluid tends to be oily. Leaks can also be difficult to diagnose, as there are many places throughout the vehicle where leaks may occur.
  • Your ABS warning light comes on your dash: This often signals that your brake fluid is running low and could be indicative of a fluid leak.
  • Your brake pads are aging: The more your car's brake pads wear, the more fluid it's going to take to help slow your vehicle down. That's why it's always a good idea to have the fluid replaced at the same time that you replace your brake pads.

The Importance of Proper Brake Fluid Care

The main purpose of brake fluid is to help your vehicle stop safely. But brake fluid also serves other key roles in your vehicle. For instance, because it helps lubricate all the parts and components of the braking system, it can also help prevent rust and corrosion.

Brake Fluid FAQs

How often do I need to change my brake fluid?

You should always consult your owner's manual to find the manufacturer's recommendations, our ask one of our network of shops who will be happy to assist you. But generally speaking, brake fluid should be replaced every 30,000 miles or every 2 years - whatever comes first.

Why does brake fluid need to be changed?

The brake system is a closed system within the vehicle. However, over time, small amounts of water tend to enter the system due to small holes in the hoses or gaps in the sealing. This water can contaminate the brake fluid over time, causing it to lose effectiveness and for it to take longer for your vehicle to come to a stop.

How do I know what type of brake fluid my vehicle takes?

Consult your owner's manual or check with your local GreatWater 360 Auto Care-affiliated shop to see if it takes glycol-based or silicone-based fluid - and what type of glycol-based or silicone-based fluid it takes.

Can I check my brake fluid level?

You can do this by checking your vehicle's brake master cylinder. You can often find this under the hood on the driver's side of the vehicle. If it's low, consider filling it with the appropriate fluid up to the fill line. If you have any doubt about how to check the fluid level or what type of brake fluid your vehicle takes, it's best to take your vehicle to a trusted auto service center in the GreatWater network.

What are some common signs that brake fluid is low or needs to be changed?

Soft brake pedals, the ABS warning light coming on your dashboard, unresponsive braking, fluid leaks, and strange noises/odd smells are all indicators that your brake fluid is low or needs to be changed.

Find a GreatWater Garage for Brake Fluid Service Today!

For more information about brake fluid, when to replace it, and why it's so important for the safe functioning of your vehicle, contact your local GreatWater-affiliated shop today. As your local network of full-service automotive repair centers, there's no job too big or too small for our experienced technicians. Contact us today for more information and to schedule an appointment to have your vehicle's brake fluid checked.