28. We’ll need to make additional hose assemblies from the evaporator under the dash to the back side of the bulkhead fitting. We start first by drilling 1 1/4-inch holes in the firewall (outside of the engine bay) to install the supplied hose grommets. Next, the #6 liquid line hose and #10 suction line hose are routed through the grommets and ends installed as shown. Ensure you are installing the proper size O-ring and using lubricant on them, too.