Enfield leg leaking

As I recall, the only place water can enter is through the swivel lock plunger. I can't remember how to prevent this but I know that water cannot get through the transom plate as I once snapped off a leg and had to bring it on board leaving the transom plate open to the water so we could carry on with the other engine. No lasting damage was done other than the broken tilt bearing.
 
There are o-rings around the swivel hub that can leak water especially if the housing has corrosion pits around the seal area, there is probably a grease nipple on top of the transom plate inside the boat, I seem to recall a hole through the swivel hub to allow gear oil to lube the hub (I welded them closed on my old ones).
I have a complete enfield leg/stern plate in my shed if you need one for spares but the internals of the leg sound rough (probably corrosion as had water in it for unknown length of time).
 
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