My w124 paeking brake has always been very ineffective. I have tried tightening the cable so that I can depress it to max 4 clicks but the cable seems to stretch in no time.

I have also replaced the brake shoes, the rear rotors before. They were really effective right after the change but it goes away soon. Right now, the parking brake cannot even stop the car in D at idle(ie creeping forward).

Is there some sort of adjustment/alignment that I have missed?

Thanks in advance
Brian

Replace the cables. They have stretched. You will be surprised how much this improves function..