Removed the upper hose in order to remove the piece broken off in there. That was the easy part.

As I'm looking at the Behr replacement fitting, the groove for the O-ring is just a bit narrower than the groove is on the broken fitting. I have the old larger O-ring, maybe I can squeeze it on there? The O-ring that comes with the Behr fitting is much thinner than the one that is on the Nissens piece.