sounds like air comes out when I press the breaks

I knowest once I purchased my 99 intrepid it started to make the noise of air coming out once hitting the break the car stops but you have to press the breaks from far away to do a complete stop..now some people tell me that its the abs system other say its the booster now one mechanic undid the abs hoes he put it back on but now the screw wont go in straight and its leaking the break fluid so please help in answering my question