CD-12 Gearcase Re-Seal

[aquasonic]

I have a Johnson CD-12 gearcase all apart and plan to replace all of the seals. The problem is that I am having a hard time sliding the ‘Gearcase Head and Bearing Assembly’ off of the Propshaft.

I think that the problem may be that the Shear Key receiver in the Propshaft may be a little distorted from prop impacts years ago, and this may be binding up the removal of the assembly.

If that is the problem, would it make sense to try to use valve grinding compound or fine sandpaper to remove any high spots on the propshaft?

[RICHARD A. WHITE]

I would think that would be ok, heck I, when first starting out used a file. my thinking was I am only hitting the high spots, and the prop rides there NOT a bearing or seal. Now I use a honing stone.

http://www.richardsoutboardtools.com
classicomctools@gmail.com

[aquasonic]

Thanks Richard.

I would greatly appreciate it if anyone has any helpful tips on resealing this gearcase up. I have the Permatex Anaerobic Sealant, and a seal kit.

Thanks

[garry-in-michigan]

This is what I have …

[aquasonic]

Thanks Garry. That certainly will help.

The only thing I’m unsure of now is the whole shift rod bushing and o-ring disassembly/reassembly, but I haven’t looked at that yet. Hopefully, that will become evident when I take a good look at it.

This motor also has a bound up shock absorber that I need to inspect. I see there is another thread on here about pressing them back to size and putting them back into service when the spring is not broken. 😀

[garry-in-michigan]

Yes, the assembled length should be 6-11/16". The factory makes a special tool for pushing out the "O" ring retainer. Of course the shift rod must be removed.

Frank Robb makes a duplicate of this tool for those that can’t afford the factory price or where with all to make there own. The alternative is to tap threads into the top of the retainer and pull it out with a long machine screw.

. . . 🙂

[garry-in-michigan]

Since the shift rod is quarter inch rod, I made my tool out of 5/16" rod a foot long. Using an electric drill clamped to my work bench (Carefully so I didn’t crush the grip or obstruct any air cooling holes) I turned down one end (with an inch wide mill file) to the quarter inch diameter of the shift rod. That turned end of the rod used another piece of notched scrap lumber clamped to the bench as a steady rest. Then I threaded the drill motor end so I could screw on a nut which would act as a stop (after filing the corners off the nut and the protruding threads off the rod) when re=installing the "O" ring retainer.

I hope that explanation is not too confusing …

[aquasonic]

Thank you Garry. I think I understand this now and it has been very educational for me. From another thread, it doesn’t sound as if Frank Robb makes the shift rod bushing tool anymore, but I can always ask him.

It looks as though the factory tool is larger in diameter than 5/16" on the ‘handle’ section probably to give it a little more contact area with the bushing and disperse the impact.

A lathe sure would be helpful for turning down some larger diameter stock. I may be calling on a machinist friend if I can’t get the tool from Frank.

[frankr]

Very few gearcases have a 5/16" diameter hole above the bushing. I found that out when somebody broke a gearcase by pounding a 5/16 rod through it anyway. As time went by, I found that the hole diameter actually varies all over the place, and I kept turning the diameter of my tool smaller and smaller to go through the smallest known hole. The last spec I used was still a few thou’s larger than the OMC factory tool. Ultimate result was that it got to where it didn’t work reliably. And the factory tool doesn’t work reliably either. So that’s why I stopped making them. You can read about an alternative way of removing the bushing at my website, http://www.franksoutboardtools.com

[aquasonic]

Frank, thanks for the very informative explanation.

The alternative method looks like a good solution to me. I would just make sure that I have a NOS bushing on hand, and plan on replacing the old one.

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