...I know this is an old post, but what did you end up finding with your issue? We are having a customer with the SAMe issue! I brought the drums back today and cut them and it almost seems like it made it worse! All new wheel cylinders and brakes and brake hardware were done in Dec 2013 and customer said this just all happaned out of the blue. I will check the backing plates Swoop, and see if they are hanging up the shoes