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Old 23-05-2012, 07:00   #1
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B&G 496 Masthead Unit

I need to replace the vane on the masthea unit, (replacement already ordered), but thought to check/change the bearings when I get the unit off the mast.
Has anyone stripped one of these units down to change the bearings. If you have, can you remember the bearing number, and any hints on how to take the unit apart.
Have looked on line, but cannot find a suitable drawing

Thanks in advance
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Old 15-06-2012, 20:27   #2
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Re: B&G 496 Masthead Unit

Damn, I was hoping to read this post and get the answer. Mine broke off about a month ago. Let me know if you figure out how to dismantle the bugger. thanks,


Craig
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Old 15-06-2012, 20:58   #3
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Re: B&G 496 Masthead Unit

http://www.tinleyelectronics.com/doc...Guidev2.10.pdf



It looks fairly simple to pull apart......

B and G Wind bearings replacement Oppedijk

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Old 16-06-2012, 07:54   #4
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Re: B&G 496 Masthead Unit

Quote:
Originally Posted by IslandHopper View Post

Thanks, found these earlier. Seems biggest problem is with the main body breaking when trying to unscrew the bearing housing.
I'll be tackling this when I get home, (2.5 weeks), and will take and notes, and post on here

Seems that patience is a virtue. The bearing housing is aluminium, the main body is plastic, and brittle with age. So a case of pentrating oil and leave to soak.'
Once the housing is off, it's said that the bearing replacement is pretty easy.

Changing the vane is pretty easy, remove the nut, take off busted vane, fit new. Hardest bit was handing over close to $150 for what amounts to a small bit of plastic with a counterweight fitted
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Old 15-07-2012, 07:28   #5
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Re: B&G 496 Masthead Unit

Just changed the bearings in the 496 mast head unit.
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
Attached Files
File Type: pdf Mast Head Unit0001.pdf (510.6 KB, 437 views)
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