At one of the pioneer museums we've visited in the last 10 years here in the west, I remember reading that they lubed their wood bearings by drunking them in a tub of warmed beef fat or tallow for hours to impregnate the wood.

Must have smelled really nice on a hot day in the sun.

I'd just get some cheap grease and use it liberally, or maybe dunk them in warm gear oil for several days.