Gimbal Bearing Assesment

[Lord Farringdon]

I have conducted a few searches but I am still not sure about what I am looking for or how to properly test the condition of my gimbal bearing. I hear a rumbling noise when I steer to port but only when I am on the plane. I ran the motor up to 1400 rpm in neutral and not a sound. But I may not understand the mechanical connection too well. I have a stern drive so presumably when the 'drive' is in neutral, the engine is still rotating the drive shaft through the gimbal bearing and therefore if there is a problem with the bearing it should show up then? Or have I got myself completely up the creek without a paddle here? Any help much appreciated.:smt001


Terry

 

[Dave S]

This is a tough one to diagnose without actually being on the boat. The gimbal bearing and the u-joints are all subject to making different noises if they are going bad. Plus if the drive is not aligned properly that puts undue stress on the gimbal bearing and can cause the coupler to fail as well. Here is a good thread to look at especially Henry Boyd's comments http://clubsearay.com/forum/showthread.php?t=34195&highlight=gimbal

I have my drive pulled off yearly and when they do that they can check the condition of the u-joints, the gimbal bearing, and the alignment. That is what I would recommend you do rather than speculate whether you may have a bad gimbal bearing. Like I said I do this annually regardless of engine hours. I also change the drive lube annually as well.

Dave

 

[Lord Farringdon]

Thanks for that link Dave. Good advice. I plan to have the boat lifted and the stern drive serviced next month so I guess I'll just get them to go a little further and check out the u drives and the bearing and replace the bellows while they are it. The boat is 5 years old, has been in the water for 3 years (was dry stacked for some of the time) and as far as I can ascetain has had regular servicings. So, I'm kind of hoping the mechanicals back there are not THAT delicate that they need this kind of work so soon (unless of course she has been badly treated). Thanks again.


Terry

 

[Daddubo]

[FONT=tahoma, new york, times, serif]
With the u-joints the noise would get better or worse with the angle of the drive. If the drive hasn't been off for 5yrs then the u-joint hasn't been greased for 5yrs and if it lets go you will wipe out a lot of expensive parts. The Gimble bearing noise will change some what with drive angle but will be more constant
[/FONT]http://www.anyairmen.com/

 

[Lord Farringdon]

Thanks for that Daddubo. The more I hear from you guys the more I am starting to understand this problem. Like any bearing, it will start to rumble at the end of its life and if I understand the gimbal bearing correctly that would happen regardless of the position of the drive (albeit it may grumble a little more at extreme angles of the drive). The U-joints on the other hand may be quiet when the drive is in central positions but will begin to protest loudly as increased angles (left/right, trim up/down) place more loading on the joints.

Although I am happy the stern drive has been serviced regularly, you raise a good point and it would be fair to say I doubt the drive has been removed in that five years so this all sounds like it is leading to a probable u-joint failing (not flailing...yet!) due to possible lack of lubrication.

This is going to be interesting. The Admiral is not going to like this!:smt009




Terry

PS: Glad your Son is home from Afghanistan safe and sound. I served in Kabul in 2002 (NZ Air Force, retired). Just this week we returned the body of one of our nations Son's killed by a roadside IED in Bamiyan Province. My prayers to his family and those of all families whose sons and daughters, brother and sisters are still serving in Iraq and Afghanistan.

 

[Dave S]

Since you have a Volvo drive it may be a bit different than a Merc.

But just for clarification, on the Merc you can grease both the drive splines and the gimbal bearing without removing the drive. The u-joints have been sealed for several years on the newer Merc drives and don't require grease. So technically you can get away without pulling the drive. BUT.......it still should be pulled to see if there is any water intrusion in the bellows areas and to check alignment as well as the condition of the u-joints and gimbal bearing.

I am about to have my dealer pull mine and probably replace the bellows as well since mine are four years old (very expensive job on a Merc:smt021).

Dave

 

[Lord Farringdon]

Our hulls are similar but power plants and drives are different. Nevertheless, one would have thought the technologies are similar, especially the sealed lube bearings. I'd be interested to know how you get on when they pull the drive on your boat Dave. Is Lake Wylie freshwater?


Terry

 

[Henry Boyd]

I just had the drive shaft replaced along with the upper drive seal and drive bearing pack this spring. At this point with the gimbal bearing that was replaced in 08 and new gimbal ring in 09, ther are no longer any functioning zerc fittings on the exterior of our 02 BIII.

Henry

 

[BonBini]

My gimble had a few slight rough spots when turning by hand when I checked with my drive off a while back. I elected to run it a while longed. It made a steady growling noise (hardly noticeable when in the water). It was more noisy when running on the muffs. When I pumped grease to it while running on the muffs, it quieted down some but soon went back to normal. I think with u-joints you should pick up more of a cycling type noise just like when your loosing one in your car.

Since then my u-joint bellows went to leaking and I then changed the gimble bearing. The Merc replacement bearing was of the non greasable type. Even though my u-joints were just greased a year earlier, when I re greased them water got pumped out of them.

 

[Daddubo]

When greasing bearings you need to make sure to use a water proof grease I use Mobile 1 Synthetic. When you re grease the Gimble make sure you use the same grease you started with or premature failure may occur due to incompatible greases.