You are over thinking the bearings. They aren't sealed or anything like  
that. They are made from UHMWPE plastic. They are connected around the furling  
tube and slide into the mast. Basically, it just accepts some load and keeps the 
 furling tube centered. Dust and spider crap gets in there and a good spray 
with  WD-40 simply cleans the crap out of there. I would imagine that a good 
spray  with a hose would do the same thing.
Picture attached.
 
Rummy

BottomofIMFTube.jpeg