two years ago I converted my 1985 +8 to rear discs and suffered from a poor handbrake this is a similar system to yours I think (sierra cosworth callipers ) what i did was first ensure the handbrake cable has a smooth run to the callipers, then remove the calliper and with a pair of pliers adjust the calliper lever to take up the slack in the auto adjust system, make sure the calliper still fits over the disc, if you go too far you will have to wind the calliper back and start again. Then do the same to the other calliper ensuring they do not bind. then move onto the handbrake cable and take up all the slack and put a bit of preload on it, road test to make sure nothing is binding or getting hot.
you will be amazed at the difference. I have put a lot of miles on my car since i did this without any problems and there are some extreme gradients where I live and it always holds OK. plus it passed the MOT without any problems.
David Byrne.
