Member Forums > Bavaria Yacht Help!

Sail drive 120S-E. Wear / groove on the prop shaft at the oil seals

(1/3) > >>

Viviane2000:
Out of precaution I wanted to replace the oil seals that are on the prop shaft. One to keep salt water out of the sail drive, one to keep the oil inside of the sail drive. When the prop shaft was out I noticed wear, a groove on the prop shaft. After some reading this seems a common problem. See pics. To my surprise there is more wear on the oil side of the seal than on the seawater side..?


* It feels that just replacing the oil seals wouldn't be the smart thing to do. But I'm not sure if this is a lot of wear or quite common. Maybe it looks worse than it is?
* Someone posted that you can replace the 2 seals (9mm thick) with 3 seals, each 6mm thick. The wear will be on a different place on the shaft so that should fix the problem for the next 20 years or so. Is there any reasoning against this?
* Should you place the seals facing: water - water - oil. Or water - oil - oil?
* For the prop shaft of the 120S-E sail drive, are these dimensions correct: outside diameter: 50,80 MM x inside diameter: 31,75 MM. The thickness of the new seals would be 6,35 MM instead of 9,52 MM.
* There are some different materials used to create seals. Is NBR the way to go?
* Does the spring of the seal need to be stainless? Inox?

geoff:
I think that I came up with the 3 seal idea. So far [about 12 years] it seems to work . I arrange with two keeping water out and 1 keeping oil in . I go for Viton seals as they only seem to use stainless springs . Viton is generally brown . Geoff

Yngmar:
We sleeved ours. If you search for speedi-sleeve here, you can find lots of information about it. Works fine.

If the inner seal has caused significant wear on the shaft, the oil was not changed soon enough and fine metal shavings from normal wear have accumulated in the oil, making it abrasive.

Viviane2000:
@geoff thanks for coming up with this solution! I ordered new seals. When these are worn in the shaft it's time to go with the speedi sleeve solution I reckon. But hopefully that's not needed for the next 10 years, and after that I'm not sure if that's still my problem  ;D

@Yngmar your explanation makes sense, when the oil is not changed enough times the metal shaving accumulate making it abrasive. I will be filling my 120S-E with new 75W90 oil, I have read different things online about gear oil vs normal engine oil needed for the sail drive. You have a 120S-E as well right? It needs the expensive gear oil, right?

I want to make sure the SD is clean on the inside from the old oil + dust and grime that worked its way in the SD when we replaced the rubber seal. Any tips on flushing the SD before filling it with gear oil?

Yngmar:
Volvo Penta changed the official recommendation to engine oil for all models except the 120S-E, which still requires 75W-90 API GL5 gear oil. It's not that expensive, about €8 a liter: https://www.ebay.it/itm/MANNOL-75W-90-SYNTHETIC-API-GL4-GL5-1-LITRO/302913396443

Compared to the cost of a new shaft, 2.6 liter of that is nothing :)

Usually when you drain it, the dirt comes out with the oil. Flushing it with a load of diesel is possible, but you'll then have to clear that out thoroughly - probably not enough benefit versus the risk of thinning the gear oil unless you want to waste a whole load of gear oil to flush out the diesel with :)

The drain plug has a recess for a small magnet that collects the metal particles, much like gear boxes in cars have (bigger ones). But for some reason the magnet is absent on most of the saildrives I've seen.

Navigation

[0] Message Index

[#] Next page