This may seem odd but I got a new bike with my first set of disc brakes. I have rode about 50 miles on them. The other day when I applied my rear brake it sounded like fluid swishing. It was wet out but I am not sure if this is normal or should I have it checked out. The brakes worked fine. Just curious if this is something which happens. Thanks.
I would guess that the rotor got dirty and was making the noise when pulling it through the caliper. The sound would have disappeared when it cleaned itself off through use.