I have a 1997 Pontiac Bonneville SSEi with 169000 miles on her now. The front and rear shocks/struts are new. The ball joints, control arm bushings, tie-rod ends, stabilizer links, sway bar bushings and tires are all new or have less than 6000 miles on them. I'm hearing a metallic scratching/grinding noise coming from what sounds to me like the right side rear of the car. I'm fairly certain that my drum brakes need to be changed and my front brakes are new as well as the calipers on both sides, but I'm unsure if the rear brakes are making that noise. It'* constant and of course only while the vehicle'* in motion. It'* been driving me nuts for about 3 weeks and it'* getting progressively louder. I just rebuilt the front suspension on this car and the front brakes are fine. So if anyone has any idea what could be causing this noise, I'd greatly appreciate the input. Also, I've checked and I can't seem to find anything that might be grinding against the wheels. So again, any help is greatly appreciated. Thanks

Fround the sounds of it, you seem to have it narrowed down to the right rear brake. Easy to determine, just raise that suspected wheel off the ground, and give it a good spin.

Based on what you have said already, I'm suspecting your old rear brakes might have broke a retaining spring and a shoe is dragging.