New-To-Me 517 and a question

[kirbykleankarpet]

I recently acquired this 517 from eBay. I love it so far, but it has a problem. The power nozzle doesn't seat firmly on the bar below the fan hole. It can wiggle a lot, and I have actually knocked it off by accident simply by kicking it slightly. Fortunately it wasn't running! But what would cause it to be so loose? Is it the wrong nozzle? Is it the nozzle lock on top? I know the belt-lifter is from a 560. It's a bit of a FrankenKirby. Look at the pictures, and see what you think. I'd love to have a solution!

In pictures 3 and 4, I moved the nozzle in each one, if you look closely, and you can see it barely sits on the bar it's supposed to rest on.

 

[kirbykleankarpet]

On a side note, the nozzle lock looks to me just like the one off of the G Series. Is this true, or is it the correct one? Or did they just never change it throughout the years?

 

[kirbykleankarpet]

I think the screw is stripped!!!

The Nozzle Lock won't tighten at all. It just spins freely. Any suggestions?