Hi, I have unscrewed the tub nut and the spud nut to loosen the vacuum
breaker tube, but I cannot slip out the tube so that I can change the
rubber vacuum breaker. Does anyone know how I can slip the tube out?
Do I need to unscrew the brass bolt that is attached to the toilet
bowl? Or should I rotate the valve body up? I tried to rolate the
valve body upward, but it is really tight and I hate to break
anything.

Here are some pictures:

http://www.sopmedia.com/sopguest/toilet/DSC03276.JPG
http://www.sopmedia.com/sopguest/toilet/DSC03277.JPG
http://www.sopmedia.com/sopguest/toilet/DSC03278.JPG

Any tips?