Tl* the contact owns a 2003 gmc yukon xl 2500. while driving approximately 70 mph, the brakes failed. when the contact attempted to apply the emergency brake to slow down the vehicle, it also failed. the contact was able to downshift enough to stop the vehicle. there were no warning indicators illuminated on the instrument panel. an independent mechanic stated that the brake lines were corroded and one of the lines was severed. in addition, brake fluid was leaking from the vehicle. the vehicle was not repaired and the manufacturer was notified. the approximate failure mileage was 166,000.