Yet another Bravo 3 drive lube leak question...

[mudsnowh2o]

Hey guys, I am a long time lurker and can usually find the answers I am looking for but this one has me a bit puzzled. I know I just need to pull the drive, I have the Merc #28 manual, and am very mechanically inclined, but I am just leaving that as the last resort since I have never had one off before. I guess I need to learn sometime, right?. I have been trying to track down a drive lube leak for a while now. The boat is a 2008, has a Bravo 3 and 350 mag, and has just over 80 hours. I bought it in the fall and upon closer inspection this spring, I could tell it had taken a hit because the skeg was about 1/2 the length it should be. That along with the fact that you can see scuff marks around the outdrive mounting nuts, tells me they have had the drive off before. I am pretty sure the lube is making it's way from the drive somewhere because the outside of the lube reservoir and the hose all the way into the transom is dry. Today I was lucky enough to catch a drip while in a contorted position with my head hanging down into the bilge, and it came from off of the starter.

I have seen quite a few posts that say people have removed the outdrive to find the U-Joint bellows full of lube, but wouldn't that lube have to come through the gimbal bearing, which would then run down where the drive shaft comes through the transom? I can find no lube anywhere near the drive shaft area. My question is what path would the lube take to get to the engine bell housing and the starter? Everything I can see from the top side of the transom is free of drive lube.

Note: I did have the dealer check the service records when I got the boat (the original owner bought the boat there and had his service done there) and it had only been in for routine maintenance besides a new impeller in 2012 so that could very well be when/why the drive was removed. I also forgot to mention the drive functions perfectly and there have never been any signs of water in the lube. Also it apparently leaks while sitting and not just while in use.

 

[mudsnowh2o]

No Title

Oh well this was not expected. I finally found where the lube is coming from. It is coming up through the shift cable and dripping out the end, down onto the valve cover, then running down and dripping off of the starter. I have attached a couple of pics showing this. I was able to find an old post with an answer by Don stating that it could be the shift shaft seal or a back cover seal ring.

Sorry apparently the uploaded images down below are not working. I am going to add a couple of links to them on Google+ so hopefully that works.

Shows lube dripping out of shift cable:
https://lh6.googleusercontent.com/-X...o/IMAG0003.jpg

Shows where the lube drips onto the valve cover:
https://lh3.googleusercontent.com/-l...o/IMAG0002.jpg

 

[dubs283]

I was able to find an old post with an answer by Don stating that it could be the shift shaft seal or a back cover seal ring.

correct

those two items are the only ones with a connection to the shift linkage cavity in the driveshaft housing

need to pull the drive and pressure test it to know for sure

 

[tpenfield]

The gear lube has its own plumbing and path into the top of the outdrive along the starboard side of the bell housing. So if you are seeing leaks of outdrive lube (and not engine oil) inside the engine compartment, then it is likely the tubing that is the problem.

Outdrives usually come off on an annual basis for u-joint inspection/greasing. So, it is not unusual to see that the bolts have been touched.

You should also check the outdrive lube itself for any presence of water (milky appearance). You will typically find oil in the bellows if the driveshaft seal is worn/leaking) (recently been there done that).

The outdrive weighs about 170 lbs +/-, so use 2 hands when you take it off

 

[alldodge]

^+1 agree, the shift cable does not go into the drive lube area. You mentioned it is lube but didn't see where you had to add any or how much. Have you had to add any?

 

[mudsnowh2o]

The gear lube has its own plumbing and path into the top of the outdrive along the starboard side of the bell housing. So if you are seeing leaks of outdrive lube (and not engine oil) inside the engine compartment, then it is likely the tubing that is the problem.

Oh how I wish it was only the tubing, but as I mentioned above, the lube path to from the bottle to the drive is dry. And the oil in the bilge is definitely drive oil.

You should also check the outdrive lube itself for any presence of water (milky appearance).

Also mentioned above that there are no signs of water in the oil

^+1 agree, the shift cable does not go into the drive lube area. You mentioned it is lube but didn't see where you had to add any or how much. Have you had to add any?

I have found other posts (one by Don S. whom you all should know), indicating that there are 2 seals that if bad can allow the lube back up through the shift cable housing. You can clearly see the lube dripping from the shift cable in the pictures.

As far as having to add any... Yes, and I would say a couple of ounces every couple weeks.

Re: Merc Bravo I: Gear oil dripping from top end of shift cable

You have either a lower shift shaft seal defective and leaking, it's in the back of the upper drive, or the back cover seal ring leaking. Both will allow gear lube in the shift linkage were the cable is. Probably the shift shaft seal.
Here is a link to a free online Merc manual for the Bravo drives. Section 3A shows the shift shaft seal and how to replace it.

 

[alldodge]

In order to leak out the shift cable your drive would have to be leaking internally out the shift shaft seal in the back of the upper housing. This would mean the entire upper area which I guess would hold about 8 ounces of lube would be full. Easy way to find out is pull the drive. When the drive is full and if the shaft housing seal is leaking, all that lube will come flowing out.

Here is a pick of where the shift cables connects and normally only has grease in it.

 

[mudsnowh2o]

It very well could be full as it has probably been leaking for a while. When we bought the boat in the fall, the bilge had drive oil in it but I though the previous owner had just spilled some.

I would like to see the picture you posted but it is not showing up for me. Also I just realized the pictures that I uploaded above are not working either so I added some links to them.

 

[alldodge]

It very well could be full as it has probably been leaking for a while. When we bought the boat in the fall, the bilge had drive oil in it but I though the previous owner had just spilled some.

I would like to see the picture you posted but it is not showing up for me. Also I just realized the pictures that I uploaded above are not working either so I added some links to them.

Looks like the only way to find out is pull the drive

 

[mudsnowh2o]

I will probably pull the drive off later this week to see what is going on in there. What else needs to be inspected on the upper end while it is off? Obviously the bellows will need to be inspected. I will need a new seal kit, right? I was in West Marine the other day and they have the Sierra branded seal kit, any problems with those?

 

[mudsnowh2o]

Sorry for all the questions but I am looking through the service manual trying to correlate everything with what I am reading on here. So I am looking at a diagram of the outdrive showing the rear cover removed. If I understand it correctly, there is an upper chamber (where the shift cams are) which would be full of lube. The shift shaft would pass through this chamber and down into a lower chamber that has the shift linkage which I would assume should not be full of lube. So, a leaking seal on that shaft, or the back cover seal, would allow lube to fill that lower chamber with the linkage, and expose the end of the cable to lube. Is this all correct or am I missing something?

If correct, then wouldn't I only need to remove the back cover to see if the shift linkage chamber is full of lube? If it is, would I then just need to pull the top cover also so the shift shaft could be removed and the seals replaced?

 

[alldodge]

Sorry for all the questions but I am looking through the service manual trying to correlate everything with what I am reading on here. So I am looking at a diagram of the outdrive showing the rear cover removed. If I understand it correctly, there is an upper chamber (where the shift cams are) which would be full of lube. The shift shaft would pass through this chamber and down into a lower chamber that has the shift linkage which I would assume should not be full of lube. So, a leaking seal on that shaft, or the back cover seal, would allow lube to fill that lower chamber with the linkage, and expose the end of the cable to lube. Is this all correct or am I missing something?

If correct, then wouldn't I only need to remove the back cover to see if the shift linkage chamber is full of lube? If it is, would I then just need to pull the top cover also so the shift shaft could be removed and the seals replaced?

Yes and No, if you remove the back it seals both gear housing and shift linkage. So the double box o-ring seal could also be leaking lube into the shift area. You could do it that way if you drained some of the lube out of the drive first, about a quart. This will put the level below the bottom of the shift area, so lube wouldn't pour into that area when the rear seal was broke by removing the back cover.

Sooner or later your going to need to remove the drive to be sure

 

[mudsnowh2o]

Thank you very much for all the help Alldodge. So the main reason for pulling the drive, would be to confirm that lube is down in the sift linkage area without breaking the seal on the back cover? If there is indeed lube in the shift linkage, would you just replace all of the seals involved, or try to determine which was leaking? I have the following seals written down...

Top Cover O Ring - 25-97387
Top Shaft Seal - 25-62705
Bottom Shaft Seal - 26-127091
Back Cover Seal - 12708

 

[alldodge]

Thank you very much for all the help Alldodge. So the main reason for pulling the drive, would be to confirm that lube is down in the sift linkage area without breaking the seal on the back cover? If there is indeed lube in the shift linkage, would you just replace all of the seals involved, or try to determine which was leaking? I have the following seals written down...

Top Cover O Ring - 25-97387
Top Shaft Seal - 25-62705
Bottom Shaft Seal - 26-127091
Back Cover Seal - 12708

Those are the correct numbers based on the average Bravo housing and will probably work. Reason I say that is because I don't know the drives serial number. Most all use those items but would like to bounce it against the parts list to make certain. If the shaft is leaking then you need to find out why it started to begin with. It's rare to have a leak in this area unless something happened to induce it. Verify you have next to no play side ways in the shift shaft prior to replacing seals. If there is some play may need to replace the bushings, and the bushing count can be 2 to 3 depending on serial number

 

[mudsnowh2o]

Finally checked the serial number today and I have not looked up the parts again but I believe this serial took a different lower shaft seal that all the others.

0W951238

 

[Fun Times]

Where you are seeing oil coming out of the shift cable, All the info above is good and it could be anyone of them allowing oil into the bell housing shift cavity. That mentioned, the most likely area should be the shifter shaft seals filling the shift cavity.

The top seal is now a plug. Merc part number 19-865866. A few of the Mercruiser techs talked about the plug in here.

http://www.offshoreonly.com/forums/...vo-1-gear-lube-leaking-housing-under-cap.html

Using either service manual 28 or 39 should get you through this with little effort. Let us know how it all goes, good luck.

 

[mudsnowh2o]

Where you are seeing oil coming out of the shift cable, All the info above is good and it could be anyone of them allowing oil into the bell housing shift cavity. That mentioned, the most likely area should be the shifter shaft seals filling the shift cavity.

The top seal is now a plug. Merc part number 19-865866. A few of the Mercruiser techs talked about the plug in here.

http://www.offshoreonly.com/forums/...vo-1-gear-lube-leaking-housing-under-cap.html

Using either service manual 28 or 39 should get you through this with little effort. Let us know how it all goes, good luck.

Yeah, you are right, it is the top seal that is different. I am going to get them ordered and will tackle this next week. For now I think I am just going to pull the top cap and the back plate and then I will pull the drive in the off-season. So here is my parts list (hoping the bushings are fine)...

19-865866 Shift Shaft top plug
26-127091
12708
25-97387

 

[alldodge]

Good to know about the plug, thanks Fun Times, will put in my notes for future use.

 

[mudsnowh2o]

Finally pulled the covers tonight. The seals really all looked pretty good and there was only a little tiny bit of side to side movement on the shaft. The shift cavity was obviously full of lube. Do I need to clean that all up and grease things in there? I have to get me another bottom seal cause I pressed it in a little cockeyed. I decided to go ahead and pull the drive and it is dry and looks good. Gimbal bearing feels smooth but could use some grease. It doesn't look like the previous owner has pumped much in there. I will report back once I get a new bottom shift shaft seal and now the seals to put drive back on.

 

[alldodge]

Finally pulled the covers tonight. The seals really all looked pretty good and there was only a little tiny bit of side to side movement on the shaft. The shift cavity was obviously full of lube. Do I need to clean that all up and grease things in there? I have to get me another bottom seal cause I pressed it in a little cockeyed. I decided to go ahead and pull the drive and it is dry and looks good. Gimbal bearing feels smooth but could use some grease. It doesn't look like the previous owner has pumped much in there. I will report back once I get a new bottom shift shaft seal and now the seals to put drive back on.

Yes, clean the area up and Merc recommends using 2-4-c grease in liberal amounts on the detent ball and pivot points. There should be next to no side play in the shift shaft. If it moves side ways this can cause another leak. But your measurement of side play is your judge. The bushings don't cost much but pulling them out and back in is usually the issue. Now if your getting the play once the shaft is mostly pulled out then that should not be an issue