My 2001 Pathfinder recently developed an odd noise when brakes are applied. The sound appears to be coming from the right rear drum brake but could also be coming from the right front disc brake, I can't quite tell. The sound begins shortly after brakes are applied and often continues after they are let off. My service manual tells me it is most likely a problem with Linings, Pads, Shims or the Return Spring in the drum brakes. I thought it most likely to be the return spring but can't find anything wrong with it or any of the others for that matter. Any thoughts?