Does anyone know the average life span of a set of drum brakes. My car has around 54k on it, and I think they may be in need of service. I just started getting a sort of scraping / dragging sound coming from the drivers side rear area. Only happens when I'm moving really slow, and even then doesn't happen all the time. At higher speeds and when braking I don't notice anything abnormal. If I get a chance today I'll pull the wheel and take a look. But if it's not the brakes, anyone know what else it might be? Thanks.