How to Check Brake Fluid

In order to check a vehicle’s brake fluid, you will first need to locate and identify the reservoir.  The location of the reservoir will vary from vehicle to vehicle, but in most cars, the brake fluid reservoir is found sitting on top of the brake master cylinder.  The brake master cylinder is typically found on the driver’s side of the vehicle up near the firewall.  The brake fluid reservoir is usually made of plastic for newer vehicles and metal for older ones. Questions on what is brake fluid?

Once located, complete the following steps in their respective order:

1. Clean the top of the reservoir – You should always clean the top of the reservoir before opening it in order to prevent dirt or other debris from falling into the reservoir. Your vehicle’s brakes can potentially become damaged by dirt or debris within the master cylinder, which can ultimately lead to the complete failure of the braking system.
2. Remove the cap of the brake fluid reservoir – If your vehicle has a plastic reservoir, simply unscrew the cap and place it to the side. If you have a metal reservoir, use a screwdriver to pry the retaining clamp off of the top before setting it off to the side. The reservoir normal sits across the car from the coolant housing.
3. Refrain from leaving the reservoir open for too long – Brake fluid is known to absorb moisture from the air. If your brake fluid absorbs enough moisture for as little as 15 minutes, your brake fluid can go bad entirely and will then need to be replaced.
4. Check the fluid level – You want your brake fluid level to be within half an inch or so of the cap. If you discover that there is no fluid within the reservoir, you may need to flush or bleed the brake system, which will be discussed more in detail later.
5. Check the color of the brake fluid – If you discover that the brake fluid is dark in color, you should replace it as a dark color is evidence of deterioration.

Performing a Brake Fluid Flush

It is recommended that you have your brakes flushed about every 30,000 miles or so.  Brake flushing involves draining all of the brake fluid from the reservoir and replacing it with unused and clean brake fluid.  Note that flushing the brake fluid and bleeding the fluid are two different procedures.

While most of us probably would give our brake fluid little to no attention, it should be stressed just how important maintaining your brakes and the fluid within it really is.  Just as the oil that powers your engine needs to be regularly replacement as it becomes contaminated and deteriorates, brake fluid also needs to be regularly replaced as it too becomes contaminated and deteriorated.

Performing a Brake Fluid Bleed

Bleeding your brakes will typically be required in the event that you continued to operate the braking system after it ran out of brake fluid, or your brake lines simply suffer from physical damage.  Both scenarios lead to air entering the brake lines, thus forming air bubbles that become trapped within the lines.

Brake bleeding involves removing just enough brake fluid in order to remove all of the air bubbles within the brake lines.  If your brake lines do have air bubbles within them, the force from the pedals will then compress the air and not the fluid, thus resulting in brakes that perform poorly or don’t break at all.

Keep You and Your Vehicle Safe

Brake fluid is a crucial component of your vehicle.  You should always make sure to document each replacement date in order to ensure that your vehicle is safe and ready to go.  While it shouldn’t be expected of everyone to memorize and master each definition and boiling point unique to their type of brake fluid, it would be in every vehicle owner’s best interest to understand the basics and risks that come with the brake fluid their vehicle requires.

Understanding the dangers of mixing brake fluid types together or the reduced braking efficiency that is a result of Glycol-Ether based fluid’s hygroscopicity can potentially avoid a disaster in the future. Always make sure you give the vehicle its proper car care.