Defective Gimbal Bearings

[Datkine]

I bought a used transom shield and the guys that sold it to me were nice enough to install a new gimbal bearing.
When I was checking the thing out I greased it and the grease came out between the bearing bore in the shield and the OD of the gimbal bearing assembly.
It's supposed to come out between the bearing races where it can grease the balls.
I pulled the gimbal bearing because it thought it was mis-indexed but found a disaster waiting to happen.
The replacement (on the right) didn't have a hole through the aluminum holder, the holder didnt have a circumferential grease groove and the bearing outer race didn't have any grease passages drilled into the ball space.
When you greased this thing the grease had nowhere to go.
This defective bearing says SKF and Mexico.
You don't want one of these in your drive.

 

[Bondo]

Re: Defective Gimbal Bearings

I bought a used transom shield and the guys that sold it to me were nice enough to install a new gimbal bearing.
When I was checking the thing out I greased it and the grease came out between the bearing bore in the shield and the OD of the gimbal bearing assembly.
It's supposed to come out between the bearing races wherView attachment 171659e it can grease the balls.
I pulled the gimbal bearing because it thought it was mis-indexed but found a disaster waiting to happen.
The replacement (on the right) didn't have a hole through the aluminum holder, the holder didnt have a circumferential grease groove and the bearing outer race didn't have any grease passages drilled into the ball space.
When you greased this thing the grease had nowhere to go.
This defective bearing says SKF and Mexico.
You don't want one of these in your drive.

Ayuh,.... Welcome Aboard,.... It Ain't defective, that's by design,...

It's a Sealed unit,... No greasin' it...

run 'er till she pukes, 'n replace it...

It's gettin' harder to find the greaseable 1s...

 

[Datkine]

Re: Defective Gimbal Bearings

Ayuh,.... Welcome Aboard,.... It Ain't defective, that's by design,...

It's a Sealed unit,... No greasin' it...

run 'er till she pukes, 'n replace it...

It's gettin' harder to find the greaseable 1s...

I saw the ball bearing was sealed and am OK with that.
With no transfer hole between the aluminum casing and the outer race there is no grease between the aluminum case and the high alloy steel outer race.
Electrochemical rot is certain.
Why go to the trouble of making a spherical bearing assembly if it corrodes and seizes quickly?
I call this a defective design and would drill the transfer hole and machine a grease ring if I get another of these.
Of course, I have a lathe and mill in my shop and am an engineer with bearing experience.

"Any grease is better than no grease!"
I used to post here as Dakine but my login won't work anymore.

 

[Don S]

Re: Defective Gimbal Bearings

The Sierra 18-2100 Gimbal bearing has the grease holes in it.
http://www.iboats.com/Gimbal-Bearin...2611441--session_id.165782505--view_id.187590

 

[Datkine]

Re: Defective Gimbal Bearings

Thanks again Don.
I just ordered one and a new seal too.

I can't imagine that the ones without a grease transfer hole won't put a bind on the drive input shaft after a bit of use.

I have run into spherically mounted bearings before in airhead BMW motorcycles.
They use them at the rear of the crank because the pressed crank assemble is pretty flexy.
The original design didn't use a spherical bearing and the solid bearing would die prematurely.
I expect that there is quite a bit of flex between the outdrive and the rubber mounted engine and a functional spherical mount is necessary to keep from overloading and failure.
As a matter of procedure, I grease a new gimbal bearing and use my alignment tool to swivel it around and free it before I try to align the engine.
Most new ones are pretty tight and I have wasted time trying to align when the gimbal bearing is frozen off shaft centerline.

How long have the new "sealed" ones been around?

 

[Datkine]

Re: Defective Gimbal Bearings

I'm not quite done with this subject.
I found a NOS OMC gimbal bearing just to see what the engineers at OMC thought a gimbal bearing should look like.
The NOS one has all the features I consider desirable.
External grease groove so grease gets all around the aluminum housing.
Transfer port in the aluminum housing so grease can get in between the aluminum bearing case and the steel outer race.
Grease holes in the outer race so grease can get to the rolling elements.
And, the machining quality is much higher than on the sealed replacement noted above.
For all that it cost me about $7 more than the re-engineered, sealed Chinese unit.
"Any grease is better than no grease at all"

 

[Don S]

Re: Defective Gimbal Bearings

OMC Sterndrive went out of business in 1998. They were bought out by Volvo. The sealed gimbal bearings didn't start until 2006 with Volvo, probably about the same time for Mercruiser. If OMC still existed today, they would probably be using the sealed bearings too.