I have a Brugnetti Simona Top DE built in the year 2000. It is working very well but there is a slight leak (drip) coming out of the steam control knob. I thought it was a simple grub screw that retained the knob to the valve spindle, but now I am not so sure. What I assumed was a grub screw, can be wobbled around but the small allen key drive appears to have been rounded out, so I am having trouble removing it.

A I said the"grub screw" is wobbling around but the knob is held securely?????? Anyone know for sure if it is a grub screw, or is there a special technique to remove the steam control knob?

Any help greatly appreciated.