Is there a way to check for a leak between Transom and OD?

[KM7]

I just pulled my OD, an OMC Cobra. I have a leak and a vibration. Water was getting into the U-Joint bellows. That caused rust on the U-Joint and damage to the U-Joint bearing. (there is another post about that called XXX.)

I thought that I was careful to prep the surfaces well last time. I cleaned off all old gasket material and use a good sealer. I'm not sure how the water got in. Is there a way to check for a leak after the OD is back on the boat and after the first time in the water?

That could have saved me an expensive repair.

See pictures of the transom surface after prepping it for the reinstall. That may not be for a while because I have to decide how to repair the U-Joint.

Also, are there better quality, and maybe thicker gaskets that prevent leaks? Last time I used Sierra brand.

 

[Lou C]

Leaks from the gasket between the drive and the pivot housing won't put water in the bellows. It will let water in the recess where the shifter bell crank moves, but not in the bellows, they are separate. The Sierra gasket for that is OK, what I do is coat the gasket on both sides with OMC gasket sealer and also on the sealing surfaces of the drive and pivot housing. That does keep water out of the recess where the shift cable/shifter bellcrank are located.
The only ways for water to get in the bellows is a defective bellows, improper installation, or rarely the grease tube that is for the gimble bearing. I have heard of that but never had that problem. Water can get in it also if the bilge is flooded but that's a very obvious problem because the water level would have to be as high as the driveshaft!
Unfortunately there is no way to know if water is getting in after you put it all back together, this is a basic problem with all I/O drive systems, be they OMC, Merc or Volvo. This is why the manufacturers say to pull the drive for maintenance each season but a lot of people especially in fresh water don't do that. Here is salt water it is a must, I have done this every year, for close to 20 years now. Next boat will be an outboard for sure, I can do this work but don't want to HAVE to do it, for years to come.
When installing the bellows I would use only an OEM bellows. In my experience if you store the boat with the drive down, the bellows can easily last 10 years. As soon as I see small cracks starting to form in the rubber between the folds, I replace it. The one on the boat now is 8 seasons old and looks good still.
Also there is a groove on the flange that it fits into, and a ridge on the inner surface of the lip of the bellows, these have to fit right. I also coat that flange with OMC gasket sealer.
Lastly, I coat the inner lip of the bellows and the bearing carrier on the drive with triple guard (Evinrude) grease this helps the seal where the bellows presses up against the bearing carrier. Also the bellows will last longer if the boat is stored with the drive down. On the Cobra bellows (at least the OEM ones) the bellows is made with one extra fold on one side, this is supposed to face down, which makes the rubber less likely to crack if the boat is stored with the drive up.
Going to try to post pix of what I was referring to....

 

[KM7]

Thank you Lou.

Re a leak going into the shifter recess and not the bellows, thanks I did not know that. I found a hole in the bellows at the 11 O-clock position where a clip for an anode ground strap should have clipped into the hose clamp. It looks like it made a hole in the bellows and caused the leak.

Re water getting into the recess for the shift lever, I pack the recess full of grease and occasionally take the plug out rinse out the grease and any dried salt and repack it with grease. No more binding shift lever.

I will use the OMC bellows.

Re storage, I always store the boat with the OD down not only to protect the bellows but also to protect the tilt – trim actuators. Fully retracted they are better protected from the weather.

Is the “ .. groove on the flange that it fits into, and a ridge on the inner surface of the lip of the bellows.” at the 4 and 8 O-clock positions? I think that you can see them in your middle picture. They might line up with the 2 bottom Allen screws for the bearing carrier.