I'm sorry that I don't have anything to offer towards why your brake failed but in the future when something as important as your brakes start making a noise they shouldn't make, investigate why.....right then, don't put it off. And that carries over to any vehicle or major appliance you rely on. As a general rule you should know a little about everything you use in your day to day life, that will vastly reduce the amount of mercy you require from strangers throughout life.