Getting back to the original task of changing the hub seal, you have to remove the bearing from the hub, because the seal is installed from the inside. Seems like some designer was a bit lax here some years ago, but that's the way it is. I rest the hub across the jaws of a vice with the studs hanging loosely between the jaws. Then I find that a 1-1/2" wrench socket fits nicely inside of the seal and mates up to the side of the inner race of the big ball bearing.

In the absence of an arbor press, my two-pound hammer comes back into play here. But I tap very gently indeed, keeping the socket and the bearing straight and going just a little at a time. Don't get carried away and start whacking it too hard, as you are pressing on the inner bearing race to get the outer race to move out of the housing. Your physical encouragement should remain well within the axial load capacity of the bearing to avoid damaging the bearing balls or the raceways. Have a little patience, and don't mind if it takes a few minutes to do this. Better a late coffee break than a damaged wheel bearing or distorted housing.