When I apply my brake I hear air?

Answer 1

*** SAFETY ALERT *** " HEARING AIR WHEN YOU APPLY THE BRAKE? " If you hear air when braking, it is NOT a good thing... It indicates that there is air in your brake fluid lines. Have someone bleed the air out of your brake lines as soon as possible. A basic explanation: There is a set of liquid-filled tubes (brake lines) going from near your brake pedal to each of your wheels. By pressing on your brake pedal you force liquid down these tubes, forcing a brake pad against each wheel and stopping your car. As long there are no bubbles of air in any of the tubes then this works great... Brake fluid with no air in it is firm, meaining that any movement at one end of a tube causes the same amount of movement of fluid at the other end. So pressing firmly on your brake pedal makes the brake pads press firmly against the wheels, safely stopping your vehicle. However, if there is any air in a brake line, then part of the movement of your brake pedal is used up trying to squeeze the brake fluid to make it firm enough to move the brakes pads. The wheezing noise - the "air" you hear - is the compression of those bubbles, a sure sign of this problem. The process that removes these bubbles is called 'bleeding' your brakes. ...You do have four tubes, one for each of the four wheels, so having one bubbly tube might still allow you to stop the car - but not very safely and probably not in a straight line since one wheel is not going to brake as well as the others do. To fix this, a mechanic will open a brake line and put brake fluid into the top end while another mechanic 'bleeds' the bubbles out of the other end of it, creating an air-free column of liquid in the line. They then close both ends of the line again so that it does not leak or get air in it again. When all tubes are air-free, you stop better and there is not any 'softness' or wheezing of 'air' when you press the brake pedal. For the your safety, please do this as soon as possible.