Start a new bag 9.

On the left side (which is now on the right, since you've flipped the thing over, but we'll still call it the left side) unscrew the set screw, #6-40, 3/16", from the collar.

I would unscrew it completely. Put it in bag 9.

Rotate the collar and move it down the shaft a bit. This is to loosen it. You probably won't have to use penetrating lubricant or lubricating penetrant.