Gear Oil Reservoir Exploded...Help

[jwfoster4]

I have a 1997, 7.4 Merc, LX EFI, Bravo 3, Duoprop - I'm stumped. My gear oil reservoir recently split while under way sending oil all in my engine compartment. The alarm went off, so no other damage done. Cleaned up, changed fluid, replaced bottle and after only 5 hours on the motor, I noticed gear oil dripping up from the prop shaft. Checked the engine and my reservoir had swollen up like a balloon and was about to pop again. Luckily, I was at a dock and caught it in time. What is causing this back pressure? Is this a known issue? Thanks

 

[Don S]

Re: Gear Oil Reservoir Exploded...Help

Your drive is DEAD. It just hasn't stopped turning the props yet.

Seen it several times on the Bravo III drives.

 

[b0mbtrack]

Re: Gear Oil Reservoir Exploded...Help

whats going on with it though, what would cause that?

 

[jwfoster4]

Re: Gear Oil Reservoir Exploded...Help

Can you be more specific...What exactly does "dead" mean. Is it overheating? Is there a fix?

 

[Don S]

Re: Gear Oil Reservoir Exploded...Help

Usually a gear gets a chip off of it, or a bearing fails. thus causing more metal. The bearings that already have a preload become pitted and have metal buildup causing excess heat and pressure in the gear case and reservoir.
Usually not much left of the internal parts. But draining the gear lube and checking the magnet would be the first step. Once you find very little gear lube and what is there is black and burned, and the magnet is covered with savings, then a complete dissassembly and inspection is in order.

 

[jwfoster4]

Re: Gear Oil Reservoir Exploded...Help

Thank you for your help. How difficult is a disassembly/inspection/rebuild? Do you just replace the offending part, or is there a specified rebuild? Would I also replace the impeller while I'm in there? I am pretty well mechanically inclined and know my way around engines, but have never cracked open a foot/outdrive. I have all service manuals and would plan to proceed on my own unless somebody talks me out of it. Thanks again for your help.

 

[Bondo]

Re: Gear Oil Reservoir Exploded...Help

The Outdrive Rebuild is just as Technical,+ Intolerent to Mistakes,+ Improper assembley as any Transmission Can Be........

I'm Not Sure,.... But you'll probably find the Factory Shop Manual in Here.......

 

[Don S]

Re: Gear Oil Reservoir Exploded...Help

When a drive goes like that, about every part in it has to be replaced. Takes a lot of special tools to get things set just right. If you don't have the special tools, you can't rebuild it.
Without knowing exactly what year or SN of your drive is, not sure this is the correct manual, but it will give you the basics of what a Bravo III will need for rebuilding.
http://www.boatfix.com/merc/Servmanl/11/11covr5x.pdf
Don't forget, the upper, and lower will be bad. The circulation of oil carries the metal particals to every area of the drive. And sometimes they can't be taken apart because gears pean over and get bigger than the housing they are in.

 

[jwfoster4]

Re: Gear Oil Reservoir Exploded...Help

Don, Thanks for the link. My number is OK151604. It looks like the manual that you sent was just the table of contents. If you have the one for my number, I would appreciate it.

 

[Bondo]

Re: Gear Oil Reservoir Exploded...Help

It looks like the manual that you sent was just the table of contents.

Keep moving,+ Watching your cursor in that table of Contents,+ You'll find the Pages of the Manual...........
The hand changes, but the text doesn't light up.....

 

[jwfoster4]

Re: Gear Oil Reservoir Exploded...Help

I saw the hand light change to the link but a window came up and said it could not open it. Am I doing something wrong?

 

[jwfoster4]

Re: Gear Oil Reservoir Exploded...Help

Nevermind...I got it to open. I was trying to open it my FireFox Browser. Once I switched it IE it worked fine. Thanks for your help.

 

[HT32BSX115]

Re: Gear Oil Reservoir Exploded...Help

I don't think FireFox is the problem. I have no problems opening the Boatfix manuals and I always use Firefox....( don't have IE. If fact I don't have Winblows either....this is Linux)


You may be at the point where it won't be very cost effective to rebuild your drive. Well it might be but If that happened to me I would probably go HERE and bite the bullet. Sorry about your dead drive. But it sounds like it's SERIOUSLY dead.

(Looks like I'll be adding a pressure switch to my drive lubricant reservoir line. I want to know when it starts pressuring up! A simple oil pressure switch will work just fine)



Regards,


Rick

 

[jwfoster4]

Re: Gear Oil Reservoir Exploded...Help

What kind of device are you adding? That's a great idea. Are you running a gauge of some type? How will you be warned when it is pressuring up? Have you had a bottle explode also? If so what did you have to do to your outdrive?

 

[tommays]

Re: Gear Oil Reservoir Exploded...Help

Don has given you the best guess from a lifetime of fixing drives

It is a simple next step to drain the gear lube and see what comes out with the oil


Tommays

 

[jwfoster4]

Re: Gear Oil Reservoir Exploded...Update

Re: Gear Oil Reservoir Exploded...Update

I have drained the gear oil and it is black and nasty and there are shavings on the magnet . And that is with only 5 hours on that oil; I changed it when the first bottle exploded.

I will not be doing any repairs myself. However, I would like to determine if the problem is in the lower or upper unit or both. I would rather only replace one or the other. It is likely that it is in the lower unit. If so, I can remove and replace it with a new or reman. myself. I would like to inspect the upper universal first though? Any tips on what to look for?

BTW, Rick are you Navy? I am a reserve HM3 here at Naval Hospital Pensacola.

 

[I/O WALDO]

Re: Gear Oil Reservoir Exploded...Help

REPLACE the drive!

 

[jwfoster4]

Re: Gear Oil Reservoir Exploded...Help

I/O Waldo - Why would an inspection not be in order? Couldn't my upper unit be ok, and therefore only the foot would need to be replaced?

 

[tommays]

Re: Gear Oil Reservoir Exploded...Help

The upper and lower drive share the same oil

Which will dammage both drives

Think of it like makeing a snowman it just piles on as it rolls


Tommays

 

[Bondo]

Re: Gear Oil Reservoir Exploded...Help

Ayuh,..........

At this point it Don't Matter Where the Problem Started,........

The Whole Drive is Trashed from all the Floating Debris........

If you change just 1/2,...... You'll be buying Another Whole drive in a Month........