Hello, I have a Trek 4900 with mechanical disc brakes. Ive had them for around two months now. since the last week, whenever I apply the brakes, they make a squealing noise- yes both of them. Is this normal? I dont have a drop in stopping power- they are just as strong as they were when I got them. Its just the noise thats annoying me- nothing else. I just want to make sure that there isnt a problem with my brakes. Can anyone help me out?