My 57 Captiva had developedadreadfulintermittent grinding and scraping noise from the front wheels which disappeared when I braked and then returned. It was bad enough to "feel" through the steering wheel. It couldn't be the pads as I'd replaced them only a month before. Eventually I realised that on the outer edge of the inboard disk of the double disks was a build-up of rust of up to about 3 or 4 mm. It was thick enough to catch on the antisqueal plates fitted behind the pads. I chipped it all off and put a thin coat of brake grease on the very edge of the disk. Noise gone!