Erik92gt

There is a knock coming from the rear of the car while breaking. So far the only thing that isnt new back there is rear wheel disc. I still have the drum breaks on. I was told that the bushings in my upper control arms were shot. I just had my upper control arms put in with new bushings still have the knocking. I have all new rear springs lower control arms and new shocks not sure what it could be. Possibly something in the axle housing or the drive shaft? Any ideas let me know.