Volvo DP-SM gimbal bearing issues

[tstewart1]

Hello,

I have twin DP-SM's and I normally pull the outdrives every year to inspect and grease the gimbal. This year, the grease in one of the gimbals looked like it had some water in it. I normally use a blue grease and the grease that was coming out of the gimbal was milky brown. The gimbal looks fine (shiny metal, spins freely with no catching, etc). The bellows look fine and I believe I replaced them 3 or so years ago. I do not see any any rust / water marks on the inside of the bellows or on the u-joints or even the gimbal. My best guess at this point is a little water is getting in through the grease tube. When I connect the grease gun I see some grease coming out of the bearing on the right side (closest to the grease tube) and very little coming out on the left side. I am getting a lot of grease coming out from behind the gimbal (between the seal and the gimbal on the right side). I am thinking either the seal is bad or the bearing is not pushed tight up agains the seal. Has anyone else seen grease coming out from behind the bearing and if so what is the most probable cause (bad seal, or bearing not fully seated)? Any suggestions on fixing it or should I just leave it?

Here's a picture of the gimbal.

Thanks
Tim

 

[bruceb58]

You need to rotate the bearing by hand to get the grease into the entire bearing. If the tube leaks, the leak is outside the bellows where the tube enters the housing.

How old are your bellows? If 5 years or older, they need to be replaced.

 

[tstewart1]

My guess is the zirc fitting or were the fitting is pressed into the tube is where the leak is. I don't think the leak is where the tube presses into bellhouse / gimbal area since it it was there I would expect to see some grease coming out of that area. I plan on replacing the tube/fitting as a good measure. Any ideas on why I am getting a lot of grease coming out from behind the bearing?

 

[alldodge]

My guess (not a VP guy) is there is more grease coming out this location because this is where the grease fitting tube meats the entry hole in the gimbal bearing. It isn't coming out the other side as much because its leaking out before it gets over there. This is not an issue, and is normal.



Is leaking out behind the bearing for the same reason as the front, and if the seal (item 5 - this is a Merc housing) is behind the bearing then this is why your seeing it

 

[bruceb58]

My guess is the zirc fitting or were the fitting is pressed into the tube is where the leak is.

That would not allow water into your housing then. If the leak was where the zerk pressed into the tube, you would not get any water into the housing because the tube is full of grease. BTW, when these do fail(not often) it's where the tube enters the housing.

I will ask again...how old are your u-joint bellows?

 

[tstewart1]

I thought about the grease in the tube as well. When I pressed the grease in, it took a lot before I saw any new grease coming out of the bearing. My assumption (could be incorrect) that the extra grease in the tube was penetrated and some of the water/ moisture did get through to the bearing. Can't really tell now that I have new grease every where. The u-joint bellows are 4 years old (replaced them early 2013). I agree that is the most obvious point of failure but I would have expected to see water in the bellows, cracks, surface rust on the ujoints and bearing which I don't have. The boat is fresh water and is stored indoors. I would expect to get more life out of the bellows than normal.

Tim

 

[bruceb58]

I would expect to get more life out of the bellows than normal.

Do you store your drive down all the time? Has the bilge ever filled with water up to the level of the driveshaft?

 

[tstewart1]

In winter (November-March) I store the boat with the drives down. During the other months I keep them up. No, I have never had water in the bilge that I couldn't explain.

 

[bruceb58]

Start storing the drives down ALL the time. The bellows will last much longer. My drive is always down unless I am trailering it. If your drive is stored up between March and November, that's too long.