Disconnecting Fuel Rails

I am trying to install a new intake manifold on my 5.0. I bought the Spring Lock Coupling Removers (Thanks again for the help on that little mystery!). I tried using them on the fuel rails but nothing seemed to be happening. Naturally there weren't any instructions. I slipped the removers over the fuel line where there was a connection - lower right side of the engine. Felt like something was happening but I still couldn't pull the line apart. Anybody done this and can give me some insight?

OK, I may have been a bit too light on the pull like a ********!! I tend to be a bit cautious, especially the first time, so as not to break anything.