Adding brake fluid to your Toyota Corolla may be necessary if you have replaced a component in the brake system, such as a caliper or master cylinder, because the fluid would have leaked during replacement. Another reason you would have to add brake fluid is if you are performing a brake bleed to flush out the old fluid. Always make sure you keep a sufficient amount of brake fluid in the master cylinder so that air doesn't enter the system.
Open the hood and prop it up.
Twist or open the cap off of the brake master cylinder. The master cylinder is usually located on the driver's-side firewall.
Pour brake fluid into master cylinder, up to the "max" line.
Replace the cap onto the brake master cylinder. Pump the brake pedal in your car a few times to remove any air in the brake system.
Close the hood.
