Why is there air coming out of my brakes?
Why is there air coming out of my brakes? A hissing noise is usually the brake booster leaking air. There could be a leak in the vacuum line, the booster diaphragm, or the master cylinder. A small leak could cause a hissing sound when you press on the brake pedal or let off. What happens if air leaks into the brake lines? With air leaking into the brake lines, the system cannot pressurize and pump brake liquid at optimal condition. Air can leak into the brake lines in very small quantities from any component with rubber seals, including the brake...