Brake Master Cylinder

When your foot pushes on the brake pedal, it engages the master cylinder to force hydraulic fluid ("brake fluid") through the master cylinder, through the brake lines and to your brake calipers and/or drums. A soft brake pedal is dangerous and the source of the problem needs to be resolved immediately. First ensure your brake fluid is full and check for brake fluid leaks throughout the system. It is always best to flush and bleed your brake fluid to ensure you have no air in your brake lines. If your brake pedal is still soft or spongy, it is likely you need to replace the master brake cylinder.