How did you adjust the brakes. Hopefully by the adjusters in the drums and not just the hand brake. If you have only used the handbrake to adjust the rears then this could be your issue. Also hopefully your repair to the handbrake bracketry has not moved the handbrake lever toward the back of the car! this will affect the amount of adjustment you have available.
Maybe you need to start over. slacken the handbrake off again and adjust the rear drums on both side until you get a small amount of drag when trying to turn the drum by hand. keep turning and adjusting until the drag is even all round. Then, you can have another shot at the handbrake. If this does not solve the problem, then maybe you need to replace the handbake cabling due to stretching, or the repair has maybe moved the lever back a tad. It does not take much to affect cable length and adjustment.
Edit. Just re read your original post. so everything is already new and properly adjusted! I suggest looking at the position of the brake lever then if you have run out of adjustment. Another thing to check is that the cables are properly fitted to the quadrants on the radius arms and the cable guide on the subframe.
Edited by Yoda, 25 June 2014 - 12:24 PM.