Well, there it is and only an O ring holds the shuttle in there? And if I understand you are saying that it comes out of the outlet to the rear brakes and not the end where the valve stem goes. The outlet to the rear brakes on mine has a small brass or steel orifice pressed into the hole a lot like the 2 outlets from the master cylinder. Exactly the size of a wire coat hanger.

How were you able to press the shuttle out?

Thanks for the good picture.