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Transom Assembly Sterndrive Shaft Seal

S

settimo velo

Contributing Member
I am wondering if I have a part missing from one of my transom assemblies ... S/No 1A174836 has what appears to be a rubber seal - for the sterndrive shaft - fitted on the inside of the gimbal bearing, whereas S/No 1A196092 does not. I have looked at a workshop manual and a parts list and they both call for a Grease Seal, but I do not know if this is the same thing as what I am concerned about i.e. a seal for the sterndrive shaft that plugs into the engine.

I am wondering if Mercruiser decided to remove this shaft seal at some point? Afterall, the Bellows are there to prevent water ingress. I can see how an additional seal would provide a fail safe, although I imagine this would be subject to a considerable amount of friction wear from a rotating shaft? ... Can anyone shed any light on this? Has my Transom got passed Mercruiser Quality Control with a critical part missing?
 
The seal is not intended to keep water out.

EDIT: {(are your transom assemblies brand new or used? If new it should be there if used then who knows....)}

It is intended to help keep grease and other contaminates from entering the bildge area I believe. Coast guard stuff so the grease and other crap can not be pumped overboard......again I think. ( the gimbal bearing was an open ball bearing and the grease went every where). I think recently they went to a sealed gimbal bearing.

It may also keep "some" water from getting from the bildge area (if water was to rise that high) to the gimbal bearing. This washes the grease out of the bearing ( open ball bearing type)

Everything I looked at says you should have the seal. When all this was removed it may have gotten damaged or lost before you received it.

Personally I do not see the need for it at all. More of a not really needed item.............

BUT if it should be there then I would get one.

Also I sent you thru regular email a mercruiser installation manual (2.2 meg) to Mike??

It should help with some stuff even though it is for newer maodels. The basics are still the same.

It also covers the thru transom exhaust topic.
 
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Thanks for the installation manual. That will be a great help re. exhausts and other issues.

My transoms are new, so I am very disappointed to find a part missing now that they are fitted to the boat. It looks like I would have to remove the gimbal bearing to fit the seal, and that would involve a special puller (?) which I do not have ... Unless it would be possible to knock the gimbal bearing out from inside the boat - through the inner transom - with a drift. I'll have a look at the bearing tomorrow to try and figure if it is an open ball or sealed bearing. However, if the seal doesn't have much of a function I'm wondering if I should bother to do anything about it. If the bilge water ever gets up that high then the boat'll probably be going down anyway!
 
kghost is right. This seal is not worth the work involved in putting it in. If you decide that you must have it installed, Sierra makes a puller and installer for the gimbal bearing. You cannot push the bearing out from the inside with out doing damage to it.
 
I would reccomend leaving it the way it is............



Doing gimbal bearings requires some effort and experience!! Also once pulled or chizzeled out they typically can NOT be reused......

If and when you get to replacing them let me know and I can send pics of my tools.

I will say, the bearing driver I had made to drive the gimbal bearing into the housing cost me $250.00, 15 years ago as I had no access to a machine shop at the time to make it myself. It works so well in my opinion Merc should have made it and sold it.....It is tight toloranced so it fits the bearing perfectly.

The tools needed to pull one out is a three jaw slide hammer puller and I modified mine with a 10 lb slide so it yanks the bearing out in two to three pulls. The puller itself is avaiable thru a tool supply such as Snap On or others.....
 
I would look at Harbor Freight for the slide hammer. Pulled my gimbal bearing with out any problem. The purchase price was much lower than other well known brand names.
 
This is because you have the new style (perma‑lube) transom assembly, And your other serial number (1A174836) does not fall within the new style transom assembly, meaning you should still have to grease the gimbal bearing up, like back in the old day's.:p:D

Service Bulletin Number 2009-69
Situation
MerCruiser transom assemblies are now equipped with a sealed, permanently lubricated (perma‑lube) gimbal bearing that does not require maintenance lubrication. Current production transoms use the perma‑lube gimbal bearing and do not require the grease fitting on the gimbal housing or the grease retention seal in front of the gimbal bearing. The specified perma‑lube gimbal bearing is the replacement gimbal bearing type for all transoms. Replacement perma‑lube gimbal bearings come with a special plug to replace the grease fitting. When replacing a lube‑style gimbal bearing with a perma‑lube bearing, it is necessary to remove the grease fitting from the transom and install the special plug.​

Models Affected
MerCruiser transom assemblies with the serial numbers listed are produced with perma‑lube gimbal bearings.
Models Covered Serial Number Range
Alpha transom 1A180260 and above
Bravo transom 1A429507 and above
Diesel Bravo 0W401503 and above​
SeaCore transom 1A433306 and above.

Serial Number 1A174836 was made on 07/10/2008.
Serial Number 1A196092 was made on 03/12/2010.
 
Thanks for getting to the bottom of that, I think we have all learnt something from that one!

It certainly explains some of the other differences between my 2 transoms.

I'll just have to remember to grease one and not the other ... I wonder which bearing I'll have to replace first?!

Do you have a link / easy look up for these Service Bulletins?
 
You will be replaceing the perma lube first from what I have heard.

If the grease hole is there and a zerk fitting can be installed I would go with the old style. If there is no fitting then just leave things the way they are...

The one in my boat is over 15 years old......I also use synthetic grease 10 pumps each year or 100 hours
 
Mercruiser have not drilled a grease hole in the casting of my 2010 produced unit, so the perma-lube bearing will have to be replaced with the same, when it goes. I can see that they've taken out some costs by introducing this modification, but I cannot see how a perma-lube is going to last 15 years + ....
 
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