OMC Cobra 350 Water in bellows

[i_build]

Just pulled the outdrive because I had clunking noise when turned to extreme left or right and was getting clicking when sustained @> 3k rpm under load... the bellows was flooded with water.

The odd thing is that there is no play on the u joints, no noise when I spin the gimble and the alignment tool slips right in.

Is the best bet right now to replace the ujoints and gimble bearing or lube it up and put in a new bellows?

I'm assuming that since it was that flooded with water that maybe the cursory tests arent revealing the true problem and i should just replace everything (u-joints bellows and gimble bearing).

The lube in the drive was like new (not milky at all).

Please advise. I can get pics if needed.

 

[Gary H NC]

Re: OMC Cobra 350 Water in bellows

I would replace the u-joints and bearing.Better to do it now than put it all back together just to have to pull it again.
You got real lucky the shaft seal did not leak.Usually the input shaft will rust and take that seal out.

 

[zbnutcase]

Re: OMC Cobra 350 Water in bellows

Yes you need to replace everything now and if it was mine I would replace input yoke seal also, although not as easy as a Merc, special tools are required. 'nutcase

 

[Gary H NC]

Re: OMC Cobra 350 Water in bellows

Yep,I agree the parts are not that expensive,
about 150 bucks replaces all of it including the bellows.

http://bpi.ebasicpower.com/c/OMC3D/Universal+Joints+for+OMC+Cobra

http://bpi.ebasicpower.com/c/OMCTSK/Transom+Service+Kits+for+OMC

 

[i_build]

Re: OMC Cobra 350 Water in bellows

The inner seal was detached from the gimble bearing when I reached in with my finger.

The drive lube wasnt milky at all but there was some fluid in the bellows that smelled curiousely like the gear lube... unless it may have been grease that had that special stink to it.

Going to pressure test the drive anyway... and get the ujoints replaced, already have the new gimble bearing and took the old one out.

Also had a heck of a time pulling the lower shift cable up... might as well replace that while I am in there as well because the jacket had a crack in it.

Thanks guys.

 

[Don S]

Re: OMC Cobra 350 Water in bellows

The inner seal was detached from the gimble bearing when I reached in with my finger.

There is not a seal attached to the gimbal bearing, there is one in front of it, put it's pressed into the gimbal housing and is seperate from the bearing. However, that is not the seal he was referring to. The input shaft seal is on the yoke that goes into the front of the drive. IF that yoke gets rusty it will take out the seal, then you will loose the gear lube out of the drive and into the bellows. NOT GOOD. Then you don't have enough gear lube in the drive and you loose a drive.

 

[i_build]

Re: OMC Cobra 350 Water in bellows

Thanks Don, I didnt realize that seal that was sitting in front of the gimbal bearing was not part of the gimbal bearing itself and unfortunately it is not part of my bellows / bearing kit so I need to get one.

The new bearing has a black ring in it while the old does not so it confused me and thought the seal was attached to the bearing.

The lube level in the drive itself was not low and it was clean, the seal behind the shaft on the drive looks good. There was no rust on the area that is within close contact so I think I may have gotten lucky.

I left the drive in an upside down position over a dry towel overnight as well. I know it's not a solid test of the seal integrity but there wasnt one drop of gear lube under it this morning.

just put the order in for 2 ujoints, the gimbal housing seal, and the new shift cable @ ebasic total 150

 

[i_build]

Re: OMC Cobra 350 Water in bellows

Found where the water was getting in from. Have only had an i/o for a year now and shame on me for not catching this earlier, but the zerk fitting that greases the gimbal bearing is not there. I keep my boat in the water and that hole is below the water line so I had a steady passage for water to get in slowly. The visual on the ujoint bellows looked good but I completely missed that missing fitting.

Now I need a zerk fitting. I can see the threads in the hole where the fitting goes, do I just use any zerk fitting to screw in there... or is it a special part? (sorry if its a stupid question just want to make sure I do this right)

 

[i_build]

Re: OMC Cobra 350 Water in bellows

Worse than i thought. It's not just the zerk fitting thats missing, the line that runs from the zerk fitting to the spot where the gimbal bearing gets the grease is completely gone. I just have 2 holes.... Need to see if they sell that line.

 

[a70eliminator]

Re: OMC Cobra 350 Water in bellows

Really, is the line not a steel tube? Oh wait a minute you wouldn't know being it's missing lol, I believe it is a steel tube.

 

[Don S]

Re: OMC Cobra 350 Water in bellows

It's a plastic tube that is just pressed into the gimbal bearing area. I have had numerous problems with the Volvo SX and DPS transom shields doing the same thing (leaking around the tube, or the tube missing).
This was one of the problems with the Cobra transom shield, and when Volvo bought out the Sterndrive section of OMC, it kept that worthless tube and zirk.
I just tap out the tube hole, with an 1/8th inch NPT tap and iinstall a SS grease zirk in it's place. (We had a bin of the zirks from the 270 and 280 volvo drives).
The tubes, even if new ones were reinstalled, also had a bad tendency to leak water into the gimbal bearing anyway.
I have tried Loctite, 5200, XYZ glue, and ABC type sealer. Nothing works except the tapping and installing a zirk. Don't ask me why, cause I can't explain why they won't seal, but they don't.

 

[i_build]

Re: OMC Cobra 350 Water in bellows

AWESOME DON! Was hoping for that reply... I have the 1/8 npt tap on hand and will do as you suggested. Thanks...

Excited about how she will run once done right... got the ujoints, shift cable, and that seal that goes in before the gimble bearing in the mail today.

Will be putting the gimble bearing in the freezer till saturday and will tap the fitting tonight....

Both exhaust and ujoint belows and gaskets are sitting in the box...

Alignment tool...

Just need to pick up the bellows adhesive, gasket adhesive, and high quality grease...

 

[a70eliminator]

Re: OMC Cobra 350 Water in bellows

Plastic tube eh, Don thanks for that info. Now I'll have to modify mine too, I'm just trying to visualize taping that little tiny pipe thread, I'm guessing it's accesable only with the drive off, I can't go look at it right now. 1/8" pipe thread seems like it would be a huge zerk?

 

[Don S]

Re: OMC Cobra 350 Water in bellows

Plastic tube eh, Don thanks for that info. Now I'll have to modify mine too, I'm just trying to visualize taping that little tiny pipe thread, I'm guessing it's accesable only with the drive off, I can't go look at it right now. 1/8" pipe thread seems like it would be a huge zerk?

Yes, it's a big zirk. I also forgot to mention one thing DO NOT.... That is DO NOT tap the treads to deep. Go a little at a time till you get it solid . Not sure how else to describe it.

The drive has to be off, along with the bellhousing. It's tight, but can be done. Keep the tap straight from the hole in the outside where the zirk was to the hole inside.

 

[i_build]

Re: OMC Cobra 350 Water in bellows

Had the tap but Don is 100% right you need the bellhousing off to tap it and I opted not to try and tap it. I found a place that had the tube for 15$ so I just went ahead and bought the tube and installed it with the zirk. Will do my best to seal around it. Its lodged in tighter than tight I used a block of wood and drove it in gently but firm. Will probably also wrap the outside edge with some epoxy. I will be lubing it frequently and pulling the drive off yearly.

Got the new ujoints on the drive, and the rest of the parts will go on tommorow. Will snap some shots as I go.

 

[rodbolt]

Re: OMC Cobra 350 Water in bellows

Ibuild,
trust me,DonS, and a few others. the cast iron input yoke to the drive WILL rust when the bellows gets full of water, may take a few months of running until it chops up the seal,leaks all the oil out of the drive and into the bellows, then destroys the upper but 90 percent of the time thats excactly what happens.
the grease tube is another story and is why some of the sx and dp drives as well as the mercruiser replacement gimbal bearings have eliminated the grease fitting and now use perma lubed bearings.
its your drive, I am just a poor tech that makes a lot of money off of others mistakes.

 

[Don S]

Re: OMC Cobra 350 Water in bellows

trust me,DonS, and a few others. the cast iron input yoke to the drive WILL rust when the bellows gets full of water, may take a few months of running until it chops up the seal,leaks all the oil out of the drive and into the bellows,

ANY, and I mean ANY boat that I pull the drive and find water in the bellows, gets the drives upper front seal replaced and the yoke checked and replaced if necessary.
I like to fix them once for the customer when they are paying for it, not 2 or 3 more times for free because I guessed wrong and something was bad when I thought it might still be good.

 

[rodbolt]

Re: OMC Cobra 350 Water in bellows

DonS is like me, with the bite marks to prove it.
happens when you do something for about 30 years.
not the first drive I ever saw water in the bellows.
however, I build may get lucky, maybe should buy lotto tickets as well .
I sell a lot of gimbal bearings,bellows and Ujoints over the counter.
almost everyone comes back with a wiped upper case.
even though I advise each and everyone to check the input yoke seal surface and replace the seal at a minimum.

 

[a70eliminator]

Re: OMC Cobra 350 Water in bellows

Had the tap but Don is 100% right you need the bellhousing off to tap it and I opted not to try and tap it. I found a place that had the tube for 15$ so I just went ahead and bought the tube and installed it with the zirk. Will do my best to seal around it. Its lodged in tighter than tight I used a block of wood and drove it in gently but firm. Will probably also wrap the outside edge with some epoxy. I will be lubing it frequently and pulling the drive off yearly.

Got the new ujoints on the drive, and the rest of the parts will go on tommorow. Will snap some shots as I go.[/QUOTE

Ibuild, does your new tube have actual threads for outside zerk? I geased mine yesterday and it pulled the zerk right out of the tube when I removed the gun, looks like I'm looking for a new tube.

 

[i_build]

Re: OMC Cobra 350 Water in bellows

Yes the tube was threaded for the zirk fitting.

As far as the shaft seal... There was no rust on the shaft whatsoever. The gearcase had not lost any lube. When I originally posted I said there was water in the bellows and what appeared to be some gear lube however it could have well been excess grease and based upon the gearcase dispstick reading exactly where I had it at the beginning of the season... I am assuming that it was.

I was planning on keeping a close eye on the level after the work. But if the pros are saying that it's impossible for that seal to have survived I will get it replaced.