How to Check Your Brake Fluid

Your car requires a number of important fluids to run properly, and brake fluid is one of them. Brake fluid makes it possible for the small amount of pressure you put on the pedal to transfer onto the brakes and bring your car to a stop. It’s important to regularly check your brake-fluid levels to ensure that your brakes keep you safe on the road. You can have this done at a mechanic’s shop, but it’s still a good idea to keep an eye on your fluids in between visits.

Important Safety Information When Checking Your Brakes

Before you check your brake fluid, you should take note of these important safety tips:

  • Brake fluid is toxic to both animals and humans. Therefore, you should take great care while working with it. Avoid getting it on your skin, and take any fluid-soaked rags to a toxic-waste disposal center versus throwing them in the garbage where they could contaminate the environment.
  • If you’re going to be changing your oil at the same time as you check your brake fluid, be careful to avoid cross contamination. Getting oil into your brake-fluid reservoir could completely destroy your brakes.
  • Brake fluid will remove paint. If you spill some of it down the side of your car while working, be sure to wipe it off right away.

How to Check your Brake Fluid

1. Locate the Brake-Fluid Reservoir

To check your fluids, you must first locate the brake-fluid reservoir. It’s usually found on the driver’s side of the engine near the brake booster and the master cylinder, but its location will vary depending on the make and model of the vehicle. Check your owner’s manual for exact specifications. Or, ask your mechanic to point out the fluid reservoir’s location the next time you take your car to the shop.

2. Clean the Top of the Reservoir

The last thing you want is for particles of dirt to get into your brake-fluid reservoir. This can cause your brakes to fail. Use a clean cloth to remove any dirt or dust from the top of the reservoir, and avoid opening it until you’re ready for the next step. Leaving it open for too long can also cause damage.

3. Open the Reservoir and Check the Fluid

When you’re ready, open the top of the fluid reservoir. If your reservoir is built into the metal master cylinder, you will probably need a screwdriver to pry off the top. Otherwise, it should just screw off.

Now, visually check the level of the brake fluid. If you see that it’s within half an inch of the top of the reservoir, you won’t need to add fluid. If the amount is lower than that, you can add some fluid yourself, but be careful not to overfill the tank. Having too much brake fluid can be just as damaging as having too little.

When to Visit a Mechanic

If you see that the tank is nearly empty, it’s important to visit a mechanic. Brake fluid shouldn’t go down on its own, so if the levels are dropping, you almost certainly have a leak. You also may need to have the entire system flushed before new fluid can be added.

When checking your fluid, also take note of its color. A dark shade is a sign that it’s time for the fluid to be flushed and replaced. It’s possible to do this yourself, but it’s a lot more complicated than changing the oil. When in doubt, visit a mechanic shop to ensure that the job is done right.

Experts recommend that you have your brake fluid flushed and replaced at least once every two years, but your vehicle might require more frequent maintenance. Check your owner’s manual for specific recommendations.

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About the Author:

James Hunt is a contributing writer for and is heavily involved in the automotive industry. You can always connect with James on Google+