Re: Bowrhruster gear pil or grease?

Bill Kinney


Grease is NOT appropriate for the bow thruster.  This is a high speed gear train and needs an oil bath.

Having oil leak while just sitting on the hard means the lip seal is bad--actually VERY bad. It is impossible to say from afar what can be wrong.  Being sure you have the right size is, of course, first.  Being sure it is installed straight, and even, is next.  If you are sure those are correct, the problem is likely the sealing surfaces themselves.  

The shaft sealing surface does eventually wear, and needs renewing.  Any roughness, scratch, or groove deep enough to feel with your fingernail is too much. I have had excellent results using a Speedi Sleeve on this surface when it has worn enough to be an issue.  

On the outside rim of the seal, where it seals on the housing, that surface can easily be scratched or gouged during the removal of the lip seal.  If there are ANY scratches there, they need to be fixed.  Sometimes this can be patched in the short run by installing the seal with a coating of RTV, but if it is damaged, it is really a machine shop job to build the surface up and machine it smooth again to the correct dimensions.

Bill Kinney
SM160, Harmonie
Charleston, SC, USA

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