Hi Judo,
On Series Landrovers (leaf sprung is what we are talking about, not series of Discos) the oil in the swivel housing makes it's way through into the bearings and lubricates them. I believe on Discos and Defenders that there is a seal that stops this from happening but I may be wrong about that. On a Series you grease the bearings so they have lubrication when first fitted until the oil works it's way through.
Cheers,
TimJ.

