Unscrew the nut on the hydro,when it is out and upright, also loosen the nut
on the compression fitting so you can take the nut off at the hydro.
Without loosing the compression ferrule nut you would have to distort the suction tube, that could lead to additional work/problems.
No you need not replace the ferrule, and when all is done just snug till it don't leak as you don't want to unnecessarily distort the tube/ferrule.
Do check the round expandable plug between mating surfaces of the hydro/
rear housing and suction tube, as they do leak and it is not uncommon to replace the cork gasket only to have the leak remain at the expandable plug.
it is about the size of a fifty cent piece.
