Residual Water in the Sail Drive

[levm]

After catching a mooring line in the prop, sea water penetrated into my SD40 Yenmar sail drive. Took the boat out of the water, drained the contaminated transmission oil put new oilseals and got her back in the water. Replaced the transmission oil three times but still the new oil becomes somewhat milky
Anyone have an idea how to get rid of that residual water in the transmission?

[Tellie]

Unfortunatly you'll need new seals. The ones you replaced seemed to have failed. Hopefully the people that replaced them will stand by their work.

[Ram]

The good news is a little water does not seem to hurt these drives- i met a guy that had not hauled his boat in 4 years and he said hes had water in the drive about 2years , with no damage- and Ive heard this story from others as well

[levm]

I believe that the new seals are OK since the oil level remains unchanged and I can sens pressure buildup when the transmission warms up.
So assuming the new oilseals are OK how do I clean the residual water?

[Ram]

Originally Posted by levm

I believe that the new seals are OK since the oil level remains unchanged and I can sens pressure buildup when the transmission warms up.
So assuming the new oilseals are OK how do I clean the residual water?

drain all the oil and refill- - seals are cheap and easy to install yourself - if i had to haul the boat i would replace the seals -again-only about $20 or less for all of them
I do this weather they leak or not at each haul out- the oil level can be the same because the oil is replaced by water- check the drain plug o-ring and replace also- Use synthetic oil when you replace this helps if you do develope a leak

[osirissail]

Originally Posted by levm

. . .Took the boat out of the water, drained the contaminated transmission oil put new oilseals and got her back in the water. Replaced the transmission oil three times but still the new oil becomes somewhat milky. . .

I would say that you needed after draining the transmission oil, you should have filled the transmission with a water absorbent fluid and run the transmission (unloaded) for a few minutes to splash the water absorbent up into the corners of the transmission. Then drain that fluid and replace with new transmission fluid a couple of times.

The idea is that water hides in corners and areas inside the transmission unless you run the transmission (unloaded) and get the fluid splashing and moving all over the inside of the casing.

If after having done all that while on the hard (out of the water), and the fluid should remain "clean." And then when you put the unit back into the water, you get whitish fluid - then there is a crack or some other damage to the housing that is allowing sea water to enter.

[levm]

I totally agree with the procedure of replacing the oilseals every time the boat is hauled out of the water, replacing also the O-rings around the prop shaft housing.
I never heard of wate absorbant fluid, is it safe to run the transmission with this fluid?

[Nemo55]

Heat the sail drive up enough to sweat out the water content in the lubricants,,,pretty difficult without stripping it all down though.

[Tellie]

You've changed the oil three times and still the oil turns milky. If you are draining all the oil each time you've got a seal problem. If you are trying to drain it from the top of the sail drive you're not getting all the oil out.

[joemac4sail]

Could it be, that the problem is not with the oil seals. but that the prop shaft was damaged slightly. Although visably ok, not enough to completely seal on the shaft. Just a thought. Regards Joe

[belizesailor]

Also, be sure you fill with correct volume. On some units overfilling can exacerbate this problem -- even with good seals.

Most sail drives I've worked with are quite tolerant of emulsified water and oil (that white mixture you likely see now in your drive) short term, but if you let them sit the water and oil will separate and this will lead to corrosion inside the drive -- potentially resulting in very expensive repairs.

[belizesailor]

Originally Posted by joemac4sail

Could it be, that the problem is not with the oil seals. but that the prop shaft was damaged slightly. Although visably ok, not enough to completely seal on the shaft. Just a thought. Regards Joe

Oh yeah...been there done this too -- with a fishing net.

If as the OP stated line was fouled around the shaft then the shaft maybe scored -- might can be corrected by machining and down-sizing the seals slightly, but pretty good odds you will need to replace the shaft. Check shaft with a micrometer to confirm.

[Tellie]

Originally Posted by belizesailor

Also, be sure you fill with correct volume. On some units overfilling can exacerbate this problem -- even with good seals.

Most sail drives I've worked with are quite tolerant of emulsified water and oil (that white mixture you likely see now in your drive) short term, but if you let them sit the water and oil will separate and this will lead to corrosion inside the drive -- potentially resulting in very expensive repairs.

I agree, ignoring an obvious problem because a few others have said they got away with it rarely works out for the best.