I bought my coach used and the previous owner had the brakes checked under warranty, they said that they could do nothing about the noise. I have had the coach to the brake shop and as soon as they heard the noise they said it was a vacuum leak but they could not find it and could not fix it. The squealing happens when you apply the bakes, whether you are stopped or moving, they make a very hi pitch noise.? Has anybody else had this problem, and can it be fixed?