High mileage vehicles can start producing a scraping or grinding noise from the rear wheels while applying the brakes. This noisecan be cause by a couple of likely problems, and is not to difficult to diagnose.
A quick removal of the rear wheels and inspection of the brake system is required to accurately diagnose the problems at hand. Check the rear brake linings for glazing and/or road dirt and greese that have built up on the brake pad. Glazed linings become very hard, which produces allot of additional sqeeks and squeels.