a/c leak 94 cutlass ciera

Hi all, Found my leak in the a/c system. It is at the firewall where the low side couples together that goes down into a black box. I can move the low side hose around and see the bubbles(using soap in a spray bottle)at the top of the box. Is the fitting screwed into the black box or is it a custom press-fit type?
Thanks. its a 3.1 v6.