Install ferrule on the stock line at the petcock end
Install ferrule on a short piece of line on the petcock side
and install original fitting and seal on the other end
Got sick of the Servi-Car pissing all the fuel out. A quick shut-off fix was in order. I had petcock laying around and I actually pulled a used ferrule off an old piece of line...Once I had the petcock installed on line it just took a little bending to make up for the extra length of the petcock so both ends fit up OK.