Does gimbal bearing need replacing?

[swift1]

How do you know when a gimbal bearing needs replacement? I pulled into a public dock over the weekend and some guy said that mine needed immediate replacement due to the noise it was making. I couldn?t really hear any noise other than the engine, but he said he heard a ?whirring? noise that was definitely a bad gimbal. While heading back to my dock, I listened for the noise he was referring too, and I was able to make out a sound that could be described as whirring, that became higher pitched as the throttle was increased. At idle there was no noise that I could make out other than the engine. Later, someone else told me that turning the steering from left to right would intensify the noise of a gimbal that needs replacing, so I tried that, but there was no difference. My manual says to remove the drive and see if there is any play in the gimbal, which would indicate it requires replacement. Before I try this are there any other ideas as to what I should be looking for as a source of this noise? 97? Mercruiser 3.0 with a SEI sterndrive that was installed last season(Alpha 1, Gen 2).

 

[Don S]

Re: Does gimbal bearing need replacing?

How do you know when a gimbal bearing needs replacement?

Gimbal bearing shouldn't make any noise at all. If someone can hear and ID the sound, then you are way past due for bearing replacement.
If there is any roughness in the bearing as you turn it by hand, it needs replaced.

 

[sr280da]

Re: Does gimbal bearing need replacing?

Gimbal bearing shouldn't make any noise at all. If someone can hear and ID the sound, then you are way past due for bearing replacement.
If there is any roughness in the bearing as you turn it by hand, it needs replaced.

Huh? My understanding (after having one replaced on a BIII) is that the gimbal bearing is the large roller bearing that supports the engine side of the drive shaft sitting between the u-joint and engine/coupler. That bearing did indeed make noise when the boat was underway and making turns to either the left or right.

Here is a link to a write up on the topic:

http://www.sterndrives.com/why_does_drive_growl.html

 

[Don S]

Re: Does gimbal bearing need replacing?

Huh? My understanding (after having one replaced on a BIII)

Ok, you're the expert, you own one and have a link.

However, the gimbal bearing is not a roller bearing.

 

[sr280da]

Re: Does gimbal bearing need replacing?

Ok, you're the expert, you own one and have a link.

However, the gimbal bearing is not a roller bearing.

Sorry you took offense, none was intended. I was merely trying to give the OP a correct answer. I'll also make another correction, the gimbal bearing is a roller bearing, and with 37 years as a practicing mechanical engineer, that is a response from an expert.

 

[ziggy]

Re: Does gimbal bearing need replacing?

the way i understand to test a gimble brg is. pull the drive and feel it (turn it by hand). it should turn w/o feel and w/o sound. totally free. just feel like nothing when ya turn it.

the gimbal bearing is a roller bearing

i don't think that's true. it's more than that. it gimbles? infinite adj. to the inner race for up down, port or starboard. not in and out. i've never took one apart or looked at it real close, but it just can't be a roller brg.

 

[Don S]

Re: Does gimbal bearing need replacing?

Yes ziggy, the inner part is a roller bearing. What I meant to say is it's not JUST a roller bearing. But I still don't own one, so I can't comment on them or the noise they can make or how to check them. That should be left to the expert.

 

[ziggy]

Re: Does gimbal bearing need replacing?

the inner part is a roller bearing. What I meant to say is it's not JUST a roller bearing.

now ya got my curiousty up?? how does it make the infinite x-y axis? rollers that are tapered on the ends ??????? i've not really thought about how they gimble, if that's the right word..

 

[bigskiohio]

Re: Does gimbal bearing need replacing?

remember this is a forum=Forum (legal), designated space for public expression. So no reason to get upset you were both right or wrong.

 

[Bt Doctur]

Re: Does gimbal bearing need replacing?

Gimbal bearings are ball bearing constructed,not roller.

 

[stonyloam]

Re: Does gimbal bearing need replacing?

now ya got my curiousty up?? how does it make the infinite x-y axis? rollers that are tapered on the ends ??????? i've not really thought about how they gimble, if that's the right word..

The rollers don't gimbal the whole bearing does. There are two parts to a gimbal bearing. The roller/ball (whichever) bearing unit and the the bearing support, one fits inside of the other. The outside of the bearing itself is machined to a convex radius which exactly matches a concave radius machined into the bearing support. This allows the bearing to swivel in any direction within the bearing support. How do they get that thing together you may ask? Look at the front (engine side of the gimbal bearing assembly) and you will see two long notches. If you turn the bearing 90 degrees to the bearing support and line it up it will slide out of the support. Try it with an old one. The way I understand it is that this is designed to compensate for instillation of the outdrive on boats that have different transom angles (relative to the engine). I have a similar setup on a shaft on one of my grain combine pickup headers. Anyway I hope i got that right.

 

[mattb1974]

Re: Does gimbal bearing need replacing?

No expert here, just trying to understand things. Why would this bearing need to "gimble"? That is what the 2 sets of ujoints are for, I thought.

 

[stonyloam]

Re: Does gimbal bearing need replacing?

No expert here, just trying to understand things. Why would this bearing need to "gimble"? That is what the 2 sets of ujoints are for, I thought.

The gimbal bearing is in the gimbal housing bolted directly to the transom, if all transoms were perfectly perpendicular to the engine coupler, you would not need a gimbal. Since different boats have different transom angles (other than 90 degrees to the coupler) the driveshaft support bearing inside of the gimbal bearing has to change its angle to allow the driveshaft to pass through directly into the coupler. Below is an example of two different transom angles, you can

C----I==I----D C-----/==/---D (C coupler D driveshaft {II, //} transom)

see the gimbal bearing (==) angle changes relative to the transom angle. Hope this helps.

 

[mattb1974]

Re: Does gimbal bearing need replacing?

The gimbal bearing is in the gimbal housing bolted directly to the transom, if all transoms were perfectly perpendicular to the engine coupler, you would not need a gimbal. Since different boats have different transom angles (other than 90 degrees to the coupler) the driveshaft support bearing inside of the gimbal bearing has to change its angle to allow the driveshaft to pass through directly into the coupler. Below is an example of two different transom angles, you can

C----I==I----D C-----/==/---D (C coupler D driveshaft II, // transom)

see the gimbal bearing (==) angle changes relative to the transom angle. Hope this helps.

Now I get it !! Thanks

 

[ziggy]

Re: Does gimbal bearing need replacing?

The outside of the bearing itself is machined to a convex radius which exactly matches a concave radius machined into the bearing support.

three statements. this makes the most sense to me. so...

the outside race, the outside of the race has a convex to it (carrier has a concave to it). it's what move in the x, y axis. it mates to the carrier. which is why ya replace the whole thing, not just the brg. as the outside of the outer race is mated to the carrier. roller brgs. like usual... do i understand right?

 

[stonyloam]

Re: Does gimbal bearing need replacing?

three statements. this makes the most sense to me. so...

the outside race, the outside of the race has a convex to it (carrier has a concave to it). it's what move in the x, y axis. it mates to the carrier. which is why ya replace the whole thing, not just the brg. as the outside of the outer race is mated to the carrier. roller brgs. like usual... do i understand right?

Huh? You got it! You actually could replace the bearing only (that is how I do it on a couple of my combine bearings), but is absolutly not recommended for a boat (that is why the notches go forward, so you can't do it).

 

[swift1]

Re: Does gimbal bearing need replacing?

Thanks for all the comments. I didn't get a chance last night to pull the drive and turn the bearing by hand but I'll keep you posted. In the sterndrive link provided above, it doesn't sound like the same issue, (noise is different, and no change when turning from side to side), but I won't know for sure until the drive is out.

 

[Utahboatnut]

Re: Does gimbal bearing need replacing?

No expert here at all but, it seems to me that if a NEW SEI drive was installed last year they would have installed a new gimbal along with it. If I were having a brand new drive installed I would pop for the new bearing at that time just so I knew all was well back there. Why was a new drive installed in the first place? A 97 model year boat should not have already blew thru a oem drive unless it was not taken care of or was in an accident either case a new gimbal should have been involved imo.

 

[swift1]

Re: Does gimbal bearing need replacing?

UPDATE - Finally had a chance to check it out and it was definitely the gimbal. Was rough to turn and had excess play in it. Took it to my mechanic to install the new one as I didn?t want to mess around without the proper tools for the job. He said it wasn?t making a significant noise either, but that it was starting to go and whoever picked out the noise at the dock had a great ear for drive sounds.
BTW Utah, hind sight is great isn?t it?! Probably should have changed it while the new drive was installed last year, but everything checked out ok so nothing else was replaced. My boat is very well taken care of, but stuff happens or there wouldn?t be a need for this type of forum, which for me is an invaluable (and often entertaining) source of information. Anyway, looking forward to being back on the water this weekend. Thanks again!