Rick,
I am not sure if that rubber piece is just a cover or what. I don't have it. If you can slide it down do so and take a look at where the line screws into the chamber. A lot of them are just compression fittings and they will leak occasionaly. Easy fix is to take it off and redo the end of the line or just try tightening it a little and see it that stops the problem. That is what I did and mine hasn't leaked a drop now for over three years.
Ron
