jl 125 11 rear break cable?

im having problems with my back break drum/cable after having to replace the cable and drum break holding arm after the drum seizing up ,locking and snapping the holding arm and cable one day ,I have replaced both but its 50/50 weather after applying the break it either comes on gradually or there's a loud click and the break locks up ,any help would be appreciate any help as my mot is due for renewal in a couple of weeks and I cant think what the problem might be ,weather I haven't got the adjustments wright or not I don't know ,please help