Bravo 3 Gear Lube Reservoir Leaking?

rmrstlmo

It appears that my gear lube reservoir is leaking.  I have gear lube on the side of engine and in the bilge. I put a real metal clamp on the hose and I'm still getting quite a bit of oil leaking out.  The reservoir will drain after about an hour of running.  Anyone else had this problem?  Any thoughts on what else it could be?  Thanks for you help.

It item 27 in the link below:

https://www.mercruiserparts.com/Show_Pictures3.asp?dnbr=809808 96&ivar=images/COMMON/18730.png&inbr=1943&bnbr=330&bdesc=OIL+RESERVOIR+COMPONENTS

Black_Diamond

Is it leaking from the reservoir or overflowing from the top? The latter is likely from the drive overheating. Watch over clamping the tube as it's just plastic you are squeezing.

BoatAway

your "on the side of the engine" comment is thought provoking... is it leaking from the hose? have you seen it leak/drip or do you just notice the level go down? It could be that the resevoir is cracked. which happens often..

rinker312

one time when I took my reservoirs off to clean I remember having the barb assembly on the bottom come loose, but couldn't get it tight without reaching into the bottle with needle nose or something and holding the float assembly in place, then I was able to get the bottom tight. 

basically the lube bottle connects to the hose and then runs to another connector at the transom.  I don't think there are any connectors in between.  I would try to wipe down all the oil and locate the leak.  Good Luck.

Babyboomer

bat32

I had this problem before I put the drive showers on my Bravo III.  They tend to overheat when up on plane for a while.  It would literally boil out of the vent in the top of the cap. I barely ever run at WOT and still had the problem.  I usually cruise at about 3200-3500 RPM. 

rmrstlmo

I've wiped it clean a couple of times and when I check it there is quite a bit of oil on the back side of the resevoir, down the side of the engine, and running down to the bilge.

I'll do some more investigating this weekend.  I never thought about it coming out the top.  Is there any other way of knowing that the drive is over heating?

bat32

If you can pull the boat and look at the drives you will see a white chalking at the top of the drive.

rmrstlmo

I believe there might have been some white-ish tint of the lube.  That must be a bad sign?

trich11

Any "milky" tint to gear lube usually indicates water in the drives. That is something you need to address quickly.

Speedracer

Are you sure that the thru transom fitting is not cracked?  I believe it is #6 on the above diagram.  I had this problem with my 272 Captiva a couple of years ago

212rowboat

Looking at the various diagrams and schematics, it appears to me that these drives are not dissimilar to differentials on a vehicle, in that the lube is 'splashed' and shouldn't be under any real pressure. 

Where does it vent? Is the vent obstructed?

I agree with the above comments, fwiw, in that the lube shouldn't have ANY whitish appearance unless water has been introduced.. that isn't good.. it would be a straight up milkshake if there was a lot, though.. was there a chance the drive was overfilled? Is there a chance it was the wrong viscosity of lube creating over expansion (boiling)? And- how does the drive unit valve between the unit and the reservoir? If whatever valve mechanism isn't valving, it could perpetually overfill the drive, which means it has to vent somewhere..

212rowboat

I just read elsewhere that the only check valve is in the reservoir cap.... huh... it may be you might want to look that diaphragm over and see if it's damaged or stuck... it certainly sounds to me like you have pressure in that system that is causing leaking when it finds somewhere else to relieve itself.. 

macgyver

I have Alpha's not Bravo's but the reservoir and cap are no doubt similar. My port reservoir was leaking, I switched the port and starboard caps, expecting possibly the leak to switch, but the leak stopped. Inspected caps, and found the port cap had been over tightened at some point, caused gasket to deform. Slight differences in reservoirs made port cap fit better on starboard reservoir.  Fixed gasket. Just another item to inspect.

Black_Diamond

@Drew, at least on the bravo III, and highly likely the other Bravo / Alpha drives are the same, you cannot over fill them, expansion of gear lube fluid is minimal when there is little air in the system and that will bubble out eventually through the reservoir bottle.  Overheating to the point you exceed the limits of the oil is another matter..and of course getting water in the oil means you have other bad problems.

212rowboat

aye... gotcha.. it's pressure building that is of concern, and reason I mentioned it..

rmrstlmo

I'll be on the boat tomorrow.  I plan on cleaning it up, refilling and i'lll try switching the caps to see if the leak goes to the other side.  I'll also see how warn the drive feels after running a little while.  Thanks for all the suggestions.

bat32

Yeah if the oil is white that is totally different.  The chaulking I talking about is actually on the top of the outdrive.  Ther was an extensive post on this on the last site.  But don't feel bad if it is boil over.  The Bravo III's are prone to this.  A hundred dollar pair of drive showers helped mine.  It was so popular on the last site they would do group purchases of them to get a better price.

rmrstlmo

The O ring in the cap was missing. Nice to have cheap fix once in a while. Thanks for everyone's help. This forum is fantastic!

bat32

Whew.... Good to hear!

Babyboomer

Good 

Dream_Inn

rmrstlmo said:

The O ring in the cap was missing. Nice to have cheap fix once in a while. Thanks for everyone's help. This forum is fantastic!

I had the same thing happen to me at the beginning of this year.  Glad you found the problem and it was an easy fix!

raybo3

Aways nice to have a nice cheap and easy fix........ =D>

craigswardmtb

I think I have the same issue. Time to switch caps and see what happens.

rmrstlmo

I was able to tell immediately by inspecting both caps side by side. Good luck.

dale332

My reservoir bottle has a crack in the top of it would this cause oil to foam/boil I ask because it only does this after on plane for awhile and as soon as you ease off and idle the oil level goes back down to correct spot? 

aero3113

dale332 said:

My reservoir bottle has a crack in the top of it would this cause oil to foam/boil I ask because it only does this after on plane for awhile and as soon as you ease off and idle the oil level goes back down to correct spot? 

Sounds like your drive is overheating? Maybe you need a drive shower to cool it?

stever3232

My gear lube raising and overflows the reservoir  while I am on plane and when I throttle back the level goes down, not sure how to fix 

stever3232

it overflows because the cap is bad but if the cap was good it would blow the cap off