2008 Hyundai Veracruz Limited AWD
 

I have a sqeak followed by a flap, flap, flap from the rear of my vehicle whenever I brake. It started about 4 months ago. I've just changed my rotors and brakes, looked for stuff inside the car that it could be, checked the mud flaps and other things that could be loose...NOTHING. I can't figure it out. Please help!