My guess is a hose.
Now to the tough part; The steering BOX (for want of a better term) is mounted at the bottom of the steering column and the 4 hoses that are threaded into it are VERY CLOSE to each other, i.e. using a flare nut wrench to either of the outer two is hard enough.
To the inner two - - Bahh, take off at least one of the outer ones first.
Yes, you DO NEED to use flare nut wrenches here and while I agree that an overnight soak in penetrating oil works for MANY things it doesn't work here - due to the "O" rings. How corrosion gets IN but penetrating oil (including power blaster) doesn't is a mystery of modern chemistry and physics.
Something to keep in mind with hose fittings is that (obviously) they aren't like turning a solid bolt, so long cheater bars are a no-no.
Tip: Don't pay ~$100 or so for Kukje original factory parts, have them made up at the local hydraulics shop for about half that and ask for smaller (than standard 19 mm) nut sizes.
Good luck with this.