2003 Accord Rear drum brake noise

[Torpito]

I recently did some rear brakes maintenance work on our 2003 Accord which resulted in knocking noise when the brakes are applied. The sound intensifies as more force is applied to the brake pedal and the frequency of the noise slows down as the car slows down. (One knock per wheel rev (approx.)) The front brakes were replaced 5k miles prior to the rear brakes maintenance work. The shoes were practically unused. The drums were re-machined and when placed back the noise started. I ended up purchasing new drums and the noise went away for 20 miles and then came back. Has anyone heard of a similar problem on drum brakes?

 

Thanks.