Stretch the coiled outer jackets with two pair of pliers. Then lace safety wire into the gap. With enough 'shimming', you can get it tightened up like factory.
usually its fixable at the knob end , the spiral cable jacket has slid down into the soft aluminum body pull the cable jacket back out and re crimp the aluminum
I know this is an old post but I'm having this same issue. There is a lot of slack in the cable and I'm not sure how to go about stretch the outer jacket that is referenced. Any ideas?