Alpha 2 top bearing

[Stinnett21]

Alpha 1 gen 2 (OM424120): I pulled my cap to take a look at things in the off season. The top bearing and cup are smooth to the touch and the bearing rotates smoothly but as you can see there is staining/discoloration. Merc Manual 14, page 3A-29 speaks of discoloration due to excessive heat being a reason for replacement. So I defer to those who know more than I, does this throw any red flags or does it appear to be typical of 16 year old bearing surfaces?

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[Bt Doctur]

Guessing there was some water contamination

 

[achris]

Guessing there was some water contamination

That's what it looks like to me too. That said, I pulled the cap off my 2006 drive and found the top bearing with the same problem. And since I have owned the drive since brand new, and know it's always had its oil changes, and never showed any signs of water...I can't explain why the bearing showed water damage.

All you can do is change it out. (And I would)

Chris.......

 

[Stinnett21]

There was briefly back around 2004. That's the only time I've seen the milk. Always dark since then. I do my own lube changes, impellers, etc. and I keep a close eye on the bottle. I've spent the last few years kinda restoring what I can with help of this forum. Guess I'm just looking for some re-assurance that I've got some time left before SEI comes knocking. Running great when I put her up. Thanks!

 

[Stinnett21]

What's involved in changing it out? I see where the cap can be bought with the cup, and I assume the shim(s), installed. Don't see how the bearing comes out of there. Manual 14 seems to indicate it just lifts out of there. Haven't pulled on it for fear of all creation flying everywhere.

 

[Bt Doctur]

the bearing is pressed onto the intermediate shaft
click to enlarge

 

[achris]

Not difficult if you have access to a press, a slide hammer and the spanner for removing the drive front cover.

Use the spanner and remove the drive gear and main bearing pack. (At this stage, I would pull the bearing pack apart and see what the bearing surfaces in those look like. You'll need a torque indicator to put the bearing pack back together.)

Lift the upper drive shaft (with the bearing on the top and the driven gear on the bottom). Inspect the bearing surface of the race left in the housing. Now press the old bearing off the shaft and the new one on.

Using a slide hammer, pull the old race from the drive top cover. DO NOT lose the shims behind the race. As bearings are made to very tight tolerances, I have never had to change the shim thickness when changing this bearing. Put the correct shims back in and very carefully press the new race into the cover (Make absolutely sure it goes in square, right from the start).

Drop the upper drive shaft back into the housing, refit the drive gear and bearing pack, fit the drive top cover.

Easy peasy.... (it's about 45 minutes, tops)

And do not buy the bearings from Merc, go to a local bearing shop. Same bearing, 1/3 the $$$
That bearing is a Timken LM11949-LM11910 (ebay sells for about $8, free shipping. https://www.ebay.com/itm/Timken-Set...898173?hash=item33e184a2fd:g:zi0AAOSwmRFaeWLA)

Chris........

 

[harringtondav]

I see a deteriorated O ring that goes around the hub in the cap and seats in the counter bore in the top of the top housing. My guess is where (some of) the water entered.The lube in the second pic of the driven gear seems to show milky lube.

Your seal troubles may go beyond this O ring. Especially if your drive has been buttoned up for 16 yrs. Follow your manual #14 and achris advice. You'll have easy access to the yoke shaft seal, if needed. I hate to be a downer, but there are four other seals/seal pairs that could be weak at that age. Check the stickies for pressure and vacuum testing process.

Good lube with frequent changes is forgiving. Good lube has a capacity for emulsifying water. The bearing shown could survive for some time with frequent lube changes. Lube is cheap, even the good stuff. But I think you'll be looking at a complete re-seal job eventually. If that bearing race starts to show pitting, it will probably be present elsewhere. Then it'll be time to dig deeper.

 

[Stinnett21]

Thanks guys! I'll ponder a path forward.

 

[Grub54891]

It also looks like silicone on the cap o ring. Ugh.

 

[Stinnett21]

achris (or anyone for that matter), I do not have the tools you mention in post #7 above but I’m willing to obtain some. Let’s say I want to replace the top bearing but don’t want to delve any deeper, i.e. pulling the bearing pack apart. I know I’m missing a good opportunity to inspect other parts but rolling torque etc. may be getting in over my head and it appears those wrenches are a bit pricey. Am I understanding you correctly that if all I replace is the top bearing/race without the bearing pack being taken apart, rolling torque does not have to be checked/reset? So if I get a retainer wrench, remove the retainer, the bearing pack can be slid out enough to allow the upper shaft to be removed, old top bearing removed, new installed along with race in cap. Is this close to being correct?

 

[achris]

Yes.

 

[Stinnett21]

Thanks Chris. That's great help!

 

[Stinnett21]

Bought a spanner wrench to remove the drive shaft retainer. Soaked retainer threads in penetrating oil overnight, wedged it under my car, used a PVC pipe on the wrench. Hasn't budged a bit. Tried hitting the wrench with dead blow (albeit a small one) as others on here have suggested. No go. Any suggestions?

 

[Bondo]

used a PVC pipe on the wrench

Ayuh,.... How Long a pipe,.......

Btw,..... Pvc is not enough to use as a cheater,...... Steel is king,....

 

[Stinnett21]

Got it! Had to use a 5 lb. sledge and a block of wood. I'm so excited! Yes I'm a boat nerd. Good news is inner bearing and race look good. Much better than top bearing. Now I have to decide between buying/renting bearing puller and slide hammer or have it done. Question: is the there any reason the race in top cover can't be removed with a puller instead of slide hammer? Manual 14 says hammer. I wonder is there a risk of deforming the cover? Thanks again to everyone.

 

[achris]

If you can get puller legs in, no reason not to...

 

[achris]

Also, when you pulled the bearing pack and drive gear out, there should have been some shims in the housing. Make sure they go back in.

 

[Stinnett21]

With it sitting horizontal (i.e normal like in use) I was able to pull it only slightly out enough to the get the upper shaft out. Think I should be ok? You guys have been a great help and inspiration thanks.

 

[Stinnett21]

In other words it's only slid back about an inch or so and still hanging