I've just got in from the garage after stripping and rebuilding my rear brakes following an MOT handbrake failure.
Even though you've replaced everything, my first question would be is there any tension in the handbrake lever. The obvious thing would be to tighten the nut at the handbrake end but if that doesn't work then jack up the rear, remove the wheels and check if the cable at the caliper end has enough tension to pull it away from it's stop and then to engage the brake.
Does the handbrake dash light come on, do the 'normal' brakes function ok?
Current cars - 1974 Spider 2000, 1978 Alfetta GTV.
Gone but not forgotten - 1999 GTV TS, 1987 Alfetta GTV, 1968 Giulia Super 1600, 1967 GT Junior 1300.