Old Alko stabiliser not gripping well

Hi

My Al-ko 2000 stabiliser from 2003 was very tight to engage for a while but at the last service the mechanic "adjusted" it and for the next couple of outings it was fine. Now however the handle goes down very easily and I don't think it is gripping. I've looked at the pads and although they need a clean, they don't seem too worn. I will probably replace them anyway but it won't help the clamping problem. Can anyone tell me what the mechanic will have adjusted last time so I can try tightening it up again?

thanks