One problem related to brake loud noise has been reported for the 2007 Toyota Prius. The most recently reported issues are listed below.
When it is humid and/or raining, the rear brakes of my 2007 Toyota Prius seize up as I come to a stop. Just before a stop (ie at a stop sign or stop light) the brakes will seem to grab really hard in the back and the car will sort of lurch or jerk forward but be abruptly held in place by the rear. There is a loud noise from the back like a rubbing noise when this happens. The car has been to two Toyota dealerships both of which deny that this could be occurring. I insisted that it be looked at and test driven and the mechanic claims there is nothing wrong. This has been going on since I first bought the car in may, 2008. Passengers have witnessed this in the car. It only happens when it is seriously humid (ie on the verge of raining) or when it is raining. . . . Every time I approach a stop, without exception. It's like the rear of the car is suddenly superglued to the road and the body of the car/shell of the car continues with the forward momentum/motion. For the category of problem I checked service brake, hydraulic, because that was the only "brake" option I saw besides parking brake. I have no idea if this is the correct category.