Brake fluid is a hydraulic fluid used in hydraulic brake and clutch systems in vehicles. It transfers force from the master cylinder to the brake calipers or wheel cylinders, actuating the brake pads or shoes to stop the vehicle.
Brake fluid is hygroscopic, meaning it absorbs moisture from the air. This can lead to a decrease in the boiling point of the brake fluid, which can cause the brakes to fail. It is important to check the brake fluid level regularly and to replace it every two years or 24,000 miles, whichever comes first.