[Shop-talk] Removing tub spout

[scott.hall at comcast.net]

Okay...so trying to replace a tub spigot that's got the 'pull up' knob to activate the shower. Its got the little slot on the underside closest to the wall, but there's not the screw I expected to be there holding the spigot to the pipe. There's what looks like a 1/4" rod running parallel to the spigot. There doesn't seem to be any mechanical 'thing' holding the spigot on the pipe, or against the wall. 

Anyone want to hazard a guess on how to get this thing off? Or how to fix the spigot so that when you pull up the knob, it stops the water flow and activates the shower (the reason I want to replace the spigot anyway). 

Thanks. 

Scott