Off hand I can’t remember, but I’m pretty sure the bowls are plastic, and it seals to an o-ring on the filter
I would Definetally get a new O-Ring... And check that bowl very closely for tiny cracks... If the bowl is an easy part to get might just replace it, you've replaced everything else may as well replace it too.
We replaced the water separator bowl and that didn’t change anything, still sucking air from somewheres
