Rebuilding the main furler worm gear box...seal orientation


karkauai
 

Thanks, Brian, that sounds like its worth a try.
--
Kent & Iris
KRISTY
SM243


Brian Gifford
 

Hey Kent, 

I would say to keep them in the original orientation (spring in) and to remove the RTV from the pitting and put in JB weld to fill the pitting. Then come in and smooth it carefully back to the original level with 180-grit or finer sandpaper to the original level. I have done this before on other aluminum casting and met with more success than with other filler options. The issue I have had previously was that the aluminum would continue to corrode under things like RTV. If you come in and remove the RTV with a small carbide burr in a dremel tool then fill with JB weld it will seal the air and water out of the porosity and give a much longer lasting seal. 

I would also recommend to check the shaft diameter with calipers and verify that the seal Inner dimension is at least 1mm smaller than the shaft diameter so that the lips have good positive force against the shaft which will prevent water intrusion. 

On my Maramu I filled the area on the outside of the gearbox (where the plastic mounting ring sits) with waterproof grease to help keep water from pooling around the shaft and causing corrosion of the shaft. My shafts were very bad around the seal to the point that I had to buy new gearboxes which will be installed when I return to my boat this fall.


--
Brian Gifford
Maramu #243
"Jamesby"
Windward/ Leeward Is.


karkauai
 

Hi All,
I'm rebuilding my gearbox for the electric furler on the Mainsail.  Not the manual furler gearbox, but the one attached to the motor.
I just did this a year ago, and there's water in it again.  The shaft seemed smooth, and the race for the two upper lip seals was slightly pitted, so I used RTV sealant.

I'm pretty sure the recommendation is to orient the seals so that they keep grease IN (ie with the springs facing toward the gears), but I'm thinking about orienting the two upper seals, or maybe just the outer one, with the springs facing up to keep water out.  I don't think there should be any issue with the grease coming out of the top of the gearbox.

Anyone ever try this?  Thoughts?  One seal or two turned around? Or leave as is and do something else?

Thanks in advance.

Stay Safe
Have Fun
Sail Fast
--
Kent & Iris
KRISTY
SM243
Still in St Michaels, MD, USA, hoping to sail to Maine this summer, but just discovered the forward head holding tank leaking around the copper discharge pipe...UGH!!!  Glad to see all the previous posts about how to fix it.