[Christ]

Check with a bearing manufacturer... they can usually have custom seals made, if you can't find them.

I always buy the same jack, over and over again, so that when one breaks, I can use another one, and when that one breaks, I can fix one of them from the other's parts.

I never refill with hydraulic fluid, either. Hydraulic fluid isn't actually necessary in a jack, as long as you're using a heavy enough fluid to not seep past the seals. Cooking oil works fine, as does used motor oil. (You won't need it often enough to actually warrant keeping your motor oil, but it still works.)

I always refill them with heavy cooking oils, since it's extremely cheap, and there's always some left in the bottle when you're done with it, that you wouldn't mess with draining in the kitchen, but for some reason, it's OK to mess with getting the last drops in the garage... (I let motor oil bottles sit upside down over a coffee can for a week too, to make sure I get all the "good stuff" out.)