Changing the U-Joint on an OMC Cobra Out Drive, OD

[KM7]

I will be changing the U-Joint on my OMC Cobra Outdrive. Water got into the OD and rusted the U-Joint and the bearing. (See Figure "Rusted UJoint")
I will either take the OD to a shop and have them replace the U-Joint and perhaps overhaul the OD OR Buy the U-Joint assy and install it myself. (See UJoint1)

Any thoughts on that? Have any of you done that yourself?

It appears that the first thing to do after removing the OD is to remove the Bearing Carrier #28.
(See Figure BearingCarrier)
I have removed the 4 Allen bolts #41 but the carrier has not come loose.
Any suggestions?
I also see that there are different thickness shims #30. That tells me that there are some detailed measurements to take to know what shim to use. That may be beyond my ability.

Any more thoughts?

 

[Scott06]

I will be changing the U-Joint on my OMC Cobra Outdrive. Water got into the OD and rusted the U-Joint and the bearing. (See Figure "Rusted UJoint")
I will either take the OD to a shop and have them replace the U-Joint and perhaps overhaul the OD OR Buy the U-Joint assy and install it myself. (See UJoint1)

Any thoughts on that? Have any of you done that yourself?

It appears that the first thing to do after removing the OD is to remove the Bearing Carrier #28.
(See Figure BearingCarrier)
I have removed the 4 Allen bolts #41 but the carrier has not come loose.
Any suggestions?
I also see that there are different thickness shims #30. That tells me that there are some detailed measurements to take to know what shim to use. That may be beyond my ability.

Any more thoughts?

Haven't done this on a cobra but have on a couple of alpha ones. With that much corrosion I would think you are also going to have to replace or put a speedi sleeve on the input yoke to drive as if the seal isnt leaking now it will shortly.

If you are paying someone it will likely be cheaper to buy a new assembly than pay labor to clean up the parts. If you are doing it your self take it apart clean up the pieces with a wire wheel or better yet sandblast, paint and then match up the u joints to a automotive application. not sure if cobras use the same u joints like gimbal bearings but the merc alphas match up to a Moog 315G for inside retaining rings and moog 344 for outside retaining rings. If you go online you can find the sizes and measure them up.

 

[Lou C]

Given the level of corrosion, I agree with the fact that the input shaft seal is likely to leak. I would think about having a shop do it, and maybe replace that whole input shaft/u-joint assembly with a good used one or aftermarket, if the OEM is not available. What year is this? I thought it was a 1992? 5.8 liter Ford?

 

[Lou C]

GLM appears to make it but the quality of their parts is questionable sometimes. I'd also check if Sierra makes it. Other options are used, or having yours restored to the point where it's usable.
OEM is not available..... Not cheap, and I'm not sure but the gear on the end may have to be pressed on and backlash set. So really a job for a pro.

OMC water pump u joint shaft assembly

GLM Marine aftermarket OMC Cobra u-joint and water pump shaft assembly years 1986 to 1993.

www.sterndrive.info

GLM version

PS looks like Sierra makes it, don't have a price though....

https://www.marineengine.com/parts/sierra-marine/sierra-marine-parts-catalog-00793.htm

 

[KM7]

Given the level of corrosion, I agree with the fact that the input shaft seal is likely to leak. I would think about having a shop do it, and maybe replace that whole input shaft/u-joint assembly with a good used one or aftermarket, if the OEM is not available. What year is this? I thought it was a 1992? 5.8 liter Ford?

Can you provide a picture of the "input shaft seal"

Correct, this is a 92 5.8 L Ford motor. Well the boat is a 91. The engine is 91. Model 584APLRGD

 

[Scott Danforth]

Can you provide a picture of the "input shaft seal"

Correct, this is a 92 5.8 L Ford motor. Well the boat is a 91. The engine is 91. Model 584APLRGD

Item 29 in the exploded view you posted in thread #1.

you will also need new crush sleeve for between the two input shaft bearings.

 

[Lou C]

When I get a chance, I'll take a look at my OMC Cobra FSM to see what the procedure is for doing this job.

 

[KM7]

If I drain the oil out of the bottom of the OD and do not see any evidence of water, can I conclude that the Input Shaft seal is intact?

New question:
Does the seal between the aft end of the bellows and the Bearing Carrier (Item #28) need to be a perfect water-tight seal? It seems to me that that area, the outer edge of the bearing retainer, should never be exposed to water.

If the Bellows is intact, and the fwd edge is water-tight with the hose clamp, then water would never be in the bellows and the seal between the aft edge of the bellows and the bearing carrier would not be wet and no seal is required. I could see that, just as an extra level of protection, you might want a seal.

The only reason for that, seems to be that IF water gets in the bellows (like it did on mine) a good seal at the aft end would prevent water from getting into the next area which is the Upper Gear Housing. Maybe that could cause serious issues making the extra seal useful.

My Bearing Carrier had corrosion 6 years ago and I repaired it using J-B Weld. I shaped it to match the original and that worked for 6 years.

Rather than replacing the Bearing Carrier ($155) + 4 hrs labor ($600), I’m going to try the JB-Weld method again. If it does not need to be a watertight seal, that would make this work easier.

I will post pictures later.

 

[Scott Danforth]

If I drain the oil out of the bottom of the OD and do not see any evidence of water, can I conclude that the Input Shaft seal is intact?

No

 

[Lou C]

The bearing carrier pushes into the aft end of the bellows and that has to seal. Now when you repaired it, is the shape the same as original? If not then that could cause a leak. One thing I have always done was coat that area of the bearing carrier with Evinrude triple guard grease and also the area of the tail end of the bellows where the bearing carrier presses into it. That helps make the seal.
The issue with corrosion of the u joint yoke is that eventually the corrosion will wear down the seal & cause it to leak, even if it’s not leaking now. See what the gear oil looks like….

 

[Lou C]

OK read the procedure for replacing the driveshaft, bearings and drive gear. This is like setting up a differential, not a job for someone who has no experience with drivetrain repairs. I would leave this one to a pro.

 

[KM7]

Lou, At first I assumed the same as you "The bearing carrier pushes into the aft end of the bellows and that has to seal." But why? The inside of the bellows should be dry and the exterior of the Bearing carrier should also be dry. What am I missing? I understand that it "looks" like it seals, but that may only be as a backup if the bellows leaks, as described above.

Yes, I am trying to match the shape of the original Bearing Carrier and I will use gasket sealer there as well.

New question. The other side of the lip on the bellows must be a water-tight seal where it sits against the back of the Pivot Housing, correct? The manual says "Coat the V-shaped lip inside the U-joint bellows opening with OMC Gasket Sealing Compound". Do you add the sealing compound and let it sit for a few minutes to let it harden a little before you work it into place against the inside of the Pivot Housing?

 

[Lou C]

Because the tail end of the bellows is snapped into the pivot housing, it doesn't attach to the bearing carrier as the front end is clamped to the gimble housing flange, therefore the bearing carrier has to be pressed into the lip of the tail end of the bellows to keep water out. When you are tightening the 6 nuts to bring the drive flush with the pivot housing against the gasket, this is what's happening, the bearing carrier is being forced into the lip at the tail end of the bellows.
Coating the bellows there and the bearing carrier with grease helps it to seal, the Triple guard grease is a very thick water proof grease.
With the OMC gasket sealing compound, it doesn't really harden much, you don't really have to wait before working the bellows into place on the flange of the gimble housing.

Also, just as an example...the Volvo SX was created by modifying the OMC transom mount, and re-designing the outdrive to use cone clutch shifting in the upper gear unit. Volvo felt that because their shift mechanism was different, and not subject to getting fouled by water intrusion, they eliminated the gasket between the drive and the pivot housing. So on the Volvo SX the only way the tail end of the bellows seals, is by the bearing carrier pushing into the bellows.
So on the original Cobra which is what you and I both have, the bellows is made water tight by the clamp on the front end with the gimble housing flange, and on the tail end by the bearing carrier pushing into the lip of the bellows. The gasket is more to keep water out of the pocket where the shift bell crank lives.

 

[KM7]

You recommend only using an OEM U-Joint Bellows. Can I get one online? What source do you trust for OEM parts?

 

[Lou C]

Marine engine.com
Been using them for years

 

[KM7]

You recommend only using an OEM U-Joint Bellows. Can I get one online? What source do you trust for OEM parts?

Nevermind. I went to the local Volvo - Penta dealer and got the Bellows, Bearing, and gaskets. Next, I will have the bearing installed by a mobile mechanic. Then I will adjust the shift cable if needed. But I may not not need to since I did not disturb anything. I did remove the shift lever in order to clean the grease out of the shift lever recess. I had filled it with grease to prevent salt build up that can interfere with the operation of the lever. That seemed to work very well. There was no salt buildup and the boat has been shifting very easily.

 

[Lou C]

What about the drive shaft & ujoints?
Once you get it right it will be fine. I have had good luck with mine now used & moored in salt water 20+ years. Pulling the drive yearly, doing pressure & vacuum tests & changing & adjusting the shift cable when needed is what it takes to make it last….

 

[KM7]

What about the drive shaft & ujoints?
Once you get it right it will be fine. I have had good luck with mine now used & moored in salt water 20+ years. Pulling the drive yearly, doing pressure & vacuum tests & changing & adjusting the shift cable when needed is what it takes to make it last….

I have not decided whether to change the U-Joints. Here are the reasons To change them:
1) Water got into the U-Joint bellows and put water on the U-Joints.
2) The boat is primarily used in salt water.
3) My U-Joints DO have Zerk fittings and while that does make lubing them possible, it can allow water to get into the U-Joint bearings. I believe that the OEM U-Joints do Not have Zerk fittings.
4) Water *Might* have gotten past the seal in the Bearing Carrier and into the OD. I will create a separate post about that called "Did Water Get Into My OD"
5) The OD is already off the boat.
6) There was a slight rumble sound coming from the OD. That might have been the U-Joints but may have only been the Gymbal Bearing. The gymbal bearing has serious rust and will be changed.
7) The Bearing Carrier would be changed at the same time. There was corrosion on it that *May* have caused a leak into the bellows. I did repair it with JB-Weld and shaped it to match the original. Replacing the Bearing Carrier would make getting a good water tight seal more likely.
8) When adding grease to the U-Joints the grease that was pushed out was dark brown (Is that normal?).

Reasons NOT to change the U-Joints
1) The U-Joints are not frozen and they move freely and smoothly.
2) There was never a screech from the U-Joints even when steering hard over left or right.
3) I could do the repair without changing the U-Joints but change the bellows and gimbal bearing and see how that works. If there is still an indication of a problem, then I would change the U-Joints. I can remove the OD myself and reinstall it easily at a minimal cost.
4) The U-Joints and Bearing retainer would add approximately $800 to the cost.
5) The boat is a 1992 Horizon 200 and I may be selling it and upgrading in a couple of years.

The bearing carrier pushes into the aft end of the bellows and that has to seal. Now when you repaired it, is the shape the same as original? If not then that could cause a leak. One thing I have always done was coat that area of the bearing carrier with Evinrude triple guard grease and also the area of the tail end of the bellows where the bearing carrier presses into it. That helps make the seal.
The issue with corrosion of the u joint yoke is that eventually the corrosion will wear down the seal & cause it to leak, even if it’s not leaking now. See what the gear oil looks like….

Here is a picture of the gear oil from the OD. It is a blueish-green color.

 

[KM7]

What is a "speedi sleeve"

 

[Lou C]

If you get brown crud out of the ujoints that’s not normal and they’ve internally rusted and must be replaced. If they fail with the boat up on plane it could tear up the transom mount & let water in the boat. Risky & potentially dangerous.
Speedy sleeve is a thin sleeve that gets installed over a shaft to make the sealing surface smooth so the seals last. Also used on trailer axles as well.
Trade for a newer boat?
Well keep in mind people are getting $20 grand for junk today. For me next boat must be an outboard.
I think you do have water in the gear oil….