Thanks a lot for your help and trouble.

Instantly after making that post I said to myself why don't I just take it off and take a look ??

I just thought that maybe one of you already knew and would just save me a step.
I followed those instructions that are posted on here a few days ago and took it apart. That was before you noticed the strange knob. But the funny thing is , I had that arm off and the little piece of the shaft that I still have left didn't fall out.It's still in there somehow with no spring to hold it ?? I'm going to take a look again and see what I come up with.
Once again thanks for your help.
Have one on me