The best writing on tune up
Squealing after the pedal has been released means that your brake wear indicators may be scraping against the rotors. Any grinding or growling results from metal on metal scraping; your brake pads have most likely worn down. Experts recommend that you seek brake repair as soon as any of these signs appear, before the problem gets any worse. Brake repair experts also recommend annual brake inspection (and repair, if needed), or twice a year inspections if you use your vehicle for heavy hauling and towing work. Your brakes are designed to function quickly and quietly; any deviation from that should be investigated as soon as possible.