Brake Fluid Warning Light
The brake fluid level warning light is activated when the level of brake fluid in the vehicle's master cylinder is low. If this light comes on, check the brake fluid level as soon as possible. If the level gets too low, air can be sucked into the brake system. The master cylinder is located under the hood on the driver's side. The fluid reservoir may have a rectangular plastic cover that snaps in place, a rectangular metal cover with a metal bail to hold it in place or a threaded cap.
Brush away any dirt or debris from on or around the master cylinder reservoir and remove the cover. Most master cylinders have two fluid chambers, one for the front brakes and one for the rear. This is to prevent the loss of both front and rear brakes in the case of a fluid leak. Both chambers should be full of brake fluid.
If the fluid level is low in one or both chambers, add the recommended brake fluid. Replace the master cylinder cover and start the vehicle. Push the brake pedal as far as it will go several times. If the travel on the pedal is the same every time and there is less than a few inches of pedal travel before the brakes engage, all should be well. If the length of travel decreases as you pump the brake pedal there is air in the system. The brake system will have to be bled. Any air in the brake system will compress as you pump the brake pedal. When you release the pedal the air with begin to expand. This can cause the brake shoes and pads to stay in contact with the drums or rotors causing excessive heat and wear.
If one of the chambers is empty, you most likely have a leaking brake line or a blown brake cylinder. Check under the vehicle for puddles of brake fluid. Also check the back side of the tires for streaks of brake fluid. Streaks of brake fluid on a tire indicate a bad wheel cylinder. A leaking or blown out wheel cylinder needs to be replaced as soon as possible. It is customary to replace both wheel cylinders on an axle when one goes bad. If one is bad, the other is likely to fail soon.
When any part of the brake fluid system is replaced or a spongy pedal exists, the brake system will need to be bled.
The loss of brake fluid is not normal. If your brake fluid light comes on, check your brake system for a problem or have it checked by a qualified mechanic as soon as possible.
