All About Brake Fluid: Answers to Your Questions


Aug 26th, 2020

All About Brake Fluid: Answers to Your Questions

Whether you're a first-time vehicle owner or a veteran car racer, you know that a car needs different types of fluids to function well. You've got your fuel, of course, but then you've got oils and lubricants and so on. Heck, even your windshield wiper has got its corresponding fluid reservoir somewhere under the hood! Among the most important fluids, of course, is the brake fluid.

How does brake fluid work?

Brake fluid is a little bit different compared to the other fluids in your car. For example, lubricants keep mechanical parts moving smoothly while absorbing a lot of the heat they generate. Fuel, on the other hand, combusts inside the engine to generate power. And then there’s the brake fluid, the primary function of which is based on hydraulic principles.

When you press your foot down on the brake pedal, that force has to be transmitted to your braking system to slow down your wheels. Brake fluid doesn't compress, so the force of your foot will not only be converted to braking pressure, but it'll also be amplified. 

That's right! 

Just a tiny bit of pressure on the brake pedal will translate to much more stopping force throughout your braking system.

What are the main types of brake fluid?

Brake fluids aren't all made the same. There are three main types of brake fluid, namely:

  1. Conventional or universal fluids based on glycol ethers - This is the most common brake fluid type used by most manufacturers around the world
  2. Silicone-based brake fluids - These can be used in conventional brake systems but shouldn't be mixed with universal fluids. You'll find them in classic cars and military vehicles.
  3. Fluids based on mineral oils - These only work in specialised braking systems and are the least common type of braking fluid

What type of brake fluid should I get?

As you can see from the brief list above, the odds are high that your car only needs conventional glycol-based brake fluids. Check your car owner's manual to figure out what type of brake fluid your vehicle uses.

It's always best to stick to the same brake fluid type when you're topping up, as mixing different types could cause the brake system to fail.

What are the signs that brake fluid is low?

Just like all the other fluids in your car, your brake fluid will run low eventually. That's normal, as long as it doesn't happen too quickly or too frequently.

If you find yourself needing to top up your brake fluids often, there might be a bigger problem at hand. Perhaps there's a leak somewhere in your brake system. Maybe it's a sign of worn brake pads. Or, you may have a damaged brake line due to wear and tear. You may want to learn more from our article on car brake maintenance.

Whatever the case may be, you can look out for the following telltale signs that the brake fluid is running low:

  1. The brake warning light comes on - The brake warning light is just a general indicator that there's a problem. Be sure to rule out low brake fluids first.
  2. No stopping power - If you press hard on the brakes, but your car still won't stop quickly, you may have a brake system problem. Low brake fluids could cause that.
  3. Recent brake replacements – Remember that brake fluids work based on hydraulic principles, so the brake lines are pressurised. If they've been opened for repairs or anything like that, you'll need to make sure that the shop added sufficient brake fluid. 

How do you top up low brake fluid?

Flushing and replacing brake fluids is something you can do on your own. However, bear in mind that workshops these days have high tech tools like brake flushing machines that can do it much more efficiently.

Still, if you're interested in topping up your low brake fluid by yourself, here are the basic steps:

  1. Find your brake fluid reservoir - every car has a tank that holds the brake fluid. Check your car owner's manual to find out where its located. Mostly, it’s located in one of the back corners of the engine compartment.
  2. Check the current fluid levels first - before you do anything, you need to know where the fluid levels are first. The brake fluid reservoir will have markings on its side to show you if you have enough brake fluid or not. To see the level clearly, shine a light through the reservoir without opening the cap. Brake fluids absorb moisture from the air, so you don't want to open the reservoir until you're ready to fill it up.
  3. Top up the brake fluid to FULL - Using a brand new, sealed container of matching brake fluid type, fill the reservoir only up to the 'FULL' mark. Never go beyond, as overfilling the reservoir could cause spillage. Again, be sure not to mix different types of brake fluids.
  4. Close the cap tightly - Once you're done, seal up the brake fluid reservoir, and that's it!

Whether it's your brake fluid or anything else about your car, fixing issues is not a problem if you know how to do it. Check out and its blog to find out how you can take better care of your vehicle! 

By Ray Hasbollah