Leaking rudder post with no packing gland

[surfmachine]

Hi, my newly purchased ally 39' sloop, a Feltz Skorpion IIA, is on the hard at Langkawi. The PO does not know how to fix it and I cant see any packing glands on the top of the shaft. So it must have some internal seals, like on a car axle?
Any one with experience of these types of rudder posts please?
It weeps at the top of the rudder post casing in heavy seas at over 6 knots.
Do I have to drop the rudder and remove the post and dig out two seals, top and bottom?
Cheers from Keith.