Gear Oil Leak Into Bilge Area After Rebuild

[cowansauto]

I have a Mercruiser Alpha 1 Gen 2 in my 1998 Maxum. I have noticed gear oil pooling in the bilge of my boat and thought it was coming from the reservoir. I put new seals on it to verify if it was the issue or not and filled it up again only to find it had leaked out again the next day. The hose and the fittings are good where it connects to the inner transom. Obviously I've left the drive up after taking it out of the water. I removed and replaced all the bellows, gimbal bearing, the oil seal behind it, u-joint shaft o-rings, etc. and it's still leaking. I have read that it could be the upper shaft seal? What seal is that exactly? Is this the one behind the gimbal bearing?

 

[m_steiger]

If the leak is confined to the engine bilge area; that is not leaking any from the outdrive, I would suspect you have a cracked or dry rotted hose going from the resavoir to the inner transom plate. It should be a pretty easy leak to track down.

 

[MarkSee]

A good possibility is the #19 seal in this link that will allow gear oil to pass through into the bilge.
Pull the drive and do a pressure test to confirm.
That was the same seal that failed on my Bravo 3 that allowed gear oil into the bilge.
You will need a couple special tools if you don't already own them.
http://www.perfprotech.com/mercruis...ng-and-drive-gears/assembly/2686/110?model=10

Mark

 

[Watermann]

The seal your talking about is the one in the upper gear case for the driveshaft, it's behind the U joints. Was there gear oil in the bellows? Put your fingers under where the driveshaft comes through into the coupler and see if there's oil there.

 

[cowansauto]

Pulled the drive loose and there was no oil in the bellows at all.

When I first noticed that this leak was going on, I replaced the gear oil reservoir hose and the fitting that connects to the transom plate fitting. I did not replace that fitting that pushes through this plate though. The fitting that came off of it appeared to be leaking a little and was a swiveling type assembly. The fitting assembly that I bought new was also this same type and was tightened down well when re-installed.

I took the boat to a marine dealer that is unable to actually fit into the bilge very well but did say that he believes that fitting is leaking that I put in???

Anyone else have any suggestions?