2001 Toyota Corolla Rear Drum Brake Knocking Noise

I recently did my own rear brake job. I own a 2001 Toyota Corolla LE. The rear had drum/brake shoe combo. I replaced both the drum (Brembo brand) and brake shoe (OEM Toyota). I had bought these parts about 2 years ago and left them in the shed. When I opened the drums, there was surface rust on it. After replacing the rear brakes, I notice on the driver rear side when I step on the brake (from around 25-30 MPH), there is a knocking noise. It does not happen all the time, just sometimes. I've recheck both rear side side and made adjustments. The hand parking brake lever pulls up about 5 clicks to prevent the rear wheels from spinning. Now if I let go of the lever, the rear right wheel will spin freely. The left rear wheel will spin freely, but have some rough patches. I know I adjusted both sides brake shoes, pretty evenly. Can my "New" 2 year old drums be warped? Or is something else not done correctly on my part? I've done rear drum repairs on my own a few times in the past without any problems.