Oil in bellows

[snoop168]

I pulled my outdrive planning to just store it inside for the winter but (not) to my surprise I found a pool of gear oil in the bellows. I say not to my surprise because all season I have had small amounts of oil in the bilge. The remote oil tank also ran low so now I’m pretty certain it’s gear oil I’ve had in my bilge all season. That being said I am in the process of pressure testing my outdrive. Initial test showed the shift shaft bushing was leaking. Changed that and now it’s holding a lot better. In about an hour it hasn’t dropped at all. So if it doesn’t leak air meaning the yoke seal is good, where did the oil come from? Is there any way it could leak directly from the reservoir into the bellows?

 

[Henry Boyd]

I assume you’re talking about Bravo series drives. The direct answer is that drive lube can only get into the bellows by coming through the drive itself. The lube comes from the reservoir mounted on the engine via a flexible tube and interfaces with a plastic fitting on the inner transom assembly. That fitting goes through the transom assembly to another bit of hose and then directly into a one way valve mounted in the bell housing. When the drive is attached to the bell housing on the transom assembly the driveshaft housing mounts against the one way valve and completes the lube circuit. Any leak in the expansion system would be external, either in the bilge, or on exterior of the drive leaving a slick in the water.

But more importantly, changing the drive seal may not have solved the problem. We found out the hard way that a bad seal can also damage the driveshaft it is sealing. The drive can also continue to hold pressure. We had a seal replaced, it continued to leak, so we had the seal redone thinking it had been damaged during installation, or was defective. When it continued to leak, the tech dug deeper. It took using a set of vernier calipers on the shaft and checking against the spec with Merc to determine the shaft had worn at the point it contacted the seal lip. The solution was to replace the entire drive shaft assembly with u-joint.

So if the seal replacement solves the problem, great. If not then the above might save some time.

 

[scoflaw]

Possible if the O-ring that's between the Transom assembly and drive is compromised

 

[snoop168]

Thanks. No it’s an alpha one gen 2 but I believe your description is the same as how mine works. So far pressure dropped about 1 psi. So I’m guessing the seal will need to be replaced. Hopefully pressure testing after that will not drop any to confirm it was the issue.

also I just replaced the shift shaft bushing assembly and what I found odd was that there was no real seal on the shaft. It just goes through the plastic bushing. I greased the shaft where it goes through the bushing but if I tweak the shift shaft at all I get air coming out of it while pressure testing. Is that normal? Did I miss something? Could the shift shaft be worn down too much or something?

 

[tony1b2000]

Had the same problem. Had the drive pressure tested. Yoke seal needed to be replaced. Since I had the drive off, I replaced the Gimbal bearing as it may have been compromised with gear lube.

 

[dvx216]

There is a seal under the threaded piece with the nylon bushing is.

 

[snoop168]

There is a seal under the threaded piece with the nylon bushing is.View attachment 95600

I was talking about the shift shaft on the lower part of the outdrive.

 

[snoop168]

Had the same problem. Had the drive pressure tested. Yoke seal needed to be replaced. Since I had the drive off, I replaced the Gimbal bearing as it may have been compromised with gear lube.

Thanks. It ended up dropping pressure so I’m going to reseal the whole upper.

 

[snoop168]

So I had someone check my yoke where it seals and he suggests changing the yoke as it looks like it’s grooved where the seal meets it. Questions are: can the groove be sanded out? If not can I just change the yoke and not worry about the universals? They seem ok. The guy suggested changing the universals too “since I was there” but at 80$ a pop I’d rather not if I don’t have to. Have some other things I know need to be done that I’d rather put the money towards.

 

[Henry Boyd]

So I had someone check my yoke where it seals and he suggests changing the yoke as it looks like it’s grooved where the seal meets it. Questions are: can the groove be sanded out? If not can I just change the yoke and not worry about the universals? They seem ok. The guy suggested changing the universals too “since I was there” but at 80$ a pop I’d rather not if I don’t have to. Have some other things I know need to be done that I’d rather put the money towards.

When I had ours done for the same issue (2013?), the only way to get the yoke from Merc was to buy a complete driveshaft with u-joint.

 

[scoflaw]

You can probably get a wear sleeve for it. Cheaper than a new shaft.