Just changed the bearings in the 496 mast head
The bearing assembly for the wind
cups just unscrews from the main body of the unit.
Holding the hub of the wind
cups, can then unscrew the capped nylon nut which retains the wind cups.
At the lower part of the bearing assembly is a small hole (covered with a bit of tape. This allows access to a very small grub screw. Back this off a couple of turns, and this will allow the threaded part of the shaft to be pulled off the main shaft.
The main shaft can then be tapped out with a suitable drift/punch. Came out very easily, along with the upper bearing. The lower bearing was lightly coroded and needed a less gentle punch.
Between the two bearings is a felt ring retained in the housing. I assumed this was to hold light oil
, so I dabbed a touch of oil on to it.
Cleaned up the housing, fitted new bearings (smeared with a light grease to prevent corrosion
between bearing and housing), and re-assembled.
Once all back together, wrapped a couple of turns of amalgamating tape at the joint between the bearing housing and the main body of the unit.
Also a couple of turns of tape over the access hole to the grub screw.
This grub screw needs a real small allen key. Not sure what size I used as the markings on allen key kit have faded. But it was the second smallest imperial sized one I had.
The small nylon capped nuts which retain the wind cups and the wind vane are crap. The one for the vane was split in two places, presumed this was UV damage. Replaced both with washer and M5 stainless nylocs.
Have attached a rough drawing of the assembly