View Full Version : Alpha gear lube leak

06-16-2010, 11:07 AM
The Alpha 2 on my 2003 18C consumes gear lube each time I use the boat. When I bought the boat last August the lower unit had been serviced within the last two months including pressure testing and alignment. The owner acknowledged that he would have to top off the gear lube each time he used the boat. If we used the boat a lot in a day the reservoir could decrease from the full line to the add line on the reservoir.

I just took it to a very reputable mechanic to have the lower unit tested and resealed. There was absolutely no water in it and it held 10 pounds pressure for 5 minutes and also held 12 pounds pressure for another 5 minutes. The mechanic said he could pull it apart but that he recommends watching it closely rather than pulling it appart since it holds pressure so well. He speculated that perhaps there is a seal that bleeds a little when the drive gets warmed up, but he hasn't run into this issue on an Alpha 2.

Please give me any advice as to what you would do in this situation. There is no leaking in the bilge whatsoever and I don't see an oil slick next to the boat, although I'm never sure if there is a trace when I'm at the dock, or if that is from the various boats at the boat ramp. Should I wait until December to have it pulled apart and resealed just to be safe? I hate to spend the $700 or so that it will cost to do the upper and lower seals and still have it seaping somewhere. Please speculate and advise.
T.M. Hayes

06-16-2010, 11:49 AM
I think the only place it could reasonably go in your situation is the bellows.

06-16-2010, 03:33 PM
I replaced the seals on my alpha. It was easy. It took a day to do it though

06-16-2010, 04:25 PM
Now for the dumb question, what are the bellows and does this need to be fixed? Is any of this work something I could dig into as relatively straight forward or does this require special tools and/or compexity?
T.M. Hayes

06-16-2010, 05:42 PM
he did a pressure test but did he do a vacume test??

three common places they leak is the top cap,it gets corroaded around the upper o'ring and lets fluid out into the water passage internally in the drive..under the impeller(upper shaft seal) and betwen the cases between the upper and lower theirs a seal that will leak..

next time out top off with gear lube and dont tighten the cap so tight, it may not be venting and forcing it out the drive whyle under way..

06-16-2010, 07:27 PM
Now for the dumb question, what are the bellows and does this need to be fixed? Is any of this work something I could dig into as relatively straight forward or does this require special tools and/or compexity?
T.M. Hayes

The bellows would have nothing to do with the fluid loss....The bellows would only be a Place to look for expelled fluid from the drive. The bellows is that BIG rubber thingy that resembles an acordian..under the drive ..when the drive is fully raised. It's about 5 inches in diameter.

We are looking for Where the fluid is going. If the drive passes a pressure test..then the drive is tight. ....in That Direction. OUT. So it's not pissing fluid OUT.

FIXX says do a Vacuum test. If the drive fails a vacuum test..this would indicate that WATER "should" be entering (sucked) into the drive. There is no water present. SO: There's a leak somewhere between the drive (which is tight) and the resevoir. ..................Or a long shot ..ARE you refilling the Drive Fluid resevoir....OR one of the "other resevoirs".

There's a Drive Fluid resevoir.
There's a Drive Trim Pump resevoir.
There's a Trim Tab Pump resevoir.

Doesn't hurt to think about the alternatives. :nilly:

06-16-2010, 07:57 PM
A vacuum test was not performed. I didn't know there was a vacuum test for the outdive but as I frequently say, what do I know, I'm a simple accountant. It is clearly losing gear lube and I am filling the correct reservoir. There is absolutely no gear lube in the bilge and no water inside the drive. I'll ask the mechanic about a vacuum test. What potential problem will a vacuum test diagnose? Thanks for all the input.
T.M. Hayes

06-16-2010, 08:23 PM
If you want a better understanding of all the bits and pieces, get yourself a manual. They're about $25.00 at any Merc dealer.
You might even find you might want to experiment a bit w/your drive.
It's not as daunting as it may seem if you understand the components.
It may also give you some ideas of where to look for a leak.

06-16-2010, 09:16 PM
The reason for the reservoir is more than added lube, it also stops the drive from developing pressure or vacuum. The reservoir allows the oil a place to go, that is the beauty the drives very rarely ingest water, there is no vacuum to pull water in like the older drives. I also think the upper U joint yoke seal is leaking, not cheap and I think you will end up seeing oil in the bilge.


06-17-2010, 08:24 AM
Vacuum test should be SOP.... Pressure & vacuum tests all seals in both directions... Pushing on the lip and pulling on the lip.

I assume it isn't leaving a puddle in the driveway or on the garage floor?