How to Guides

How to Check Brake Fluid Levels

Wil Parker posted this on May 20, 2014

How to Check Brake Fluid Levels

Your cars brake system relies on numerous parts to stop your car when you need it, all of which would be completely useless without brake fluid pumping through the system.  When you step on the brake pedal it is the release of this fluid that will ultimately lead to stopping your spinning tires.  Making sure there is enough brake fluid in the system is essential to ensuring that your brakes work every time you need them to.

Why Use a Fluid?

While it may seem like direct force would be a much easier solution to stopping your car than the indirect use of a fluid, there is good reason why cars brake systems are not designed that way.  Liquids don’t compress when you apply pressure and you don’t feel their force at work.  On the other hand, consider how you stop another moving object like a bike.  When you use your feet to try and stop its motion you feel those vibrations as the bike slows down and stops.  The same would hold true if a mechanical set up initiated by your foot stopped your car except at a much greater force.

Why Does the Level Matter?

Like mentioned above, without brake fluid your entire brake system becomes obsolete.  But there is another reason to check the level.  Air in the brake lines will cause a delay in your braking time.  When you allow the brake fluid level to get too low you are risking air entering the system through the reservoir.  Keeping it full prevents that from happening.


Tools For the Job

  1. A screw driver
  2. Work gloves
  3. Clean, lint free towel

Getting the Job Done

  1. First thing you have to do is find the brake master cylinder.  That’s the reservoir where the brake fluid is stored.  It is usually towards the front of the engine on the driver’s side and looks like a small, plastic canister.
  2. Once you find it, clean off the top with your work towel.  Just like air, you don’t want any dirt to get inside your brake fluid and contaminate it.
  3. Some types of reservoirs will just have a screw top, while others will require that you use a screwdriver to open the retaining clamp on top.
  4. Look inside to make sure there is no more than half an inch between the level of brake fluid and the cap. If there is, add enough clean fluid to raise the level.
  5. Now you just replace the top securely and you’re done. Not much to that task at all.


Helpful Hints

  • If your car is equipped with anti-lock brakes check your owner’s manual before opening the master cylinder.  Some ABS systems require that the brake pedal is pumped repeatedly before you open the reservoir.
  • Don’t leave the master cylinder or the bottle of brake fluid open.  If moist air gets inside either one, the brake fluid will be ruined.  Now instead of just a simple brake fluid check, you have gotten yourself into a complicated brake fluid change.
  • Check the color of the brake fluid while you have the master cylinder open.  If it is very dark it may need to be flushed and drained. Ask your mechanic to have a look-see.
  • Your brake fluid should be changed every year to avoid contaminants inside ruining other components in the system.
  • Use your gloves when dealing with brake fluid as it is a toxic material that you want to avoid contact with.
  • Brake fluid is so caustic that it will eat right through the paint on your car.  Clean up any spills immediately with a clean towel.
  • If you are interested in learning more about brake fluid and how to check it, watch this video.  Not only will you learn how to add to your brake fluid levels, the pros will explain why it is important. 


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