Bad Gimble bearing or Ujoints?

[Wellcraft170]

hello everyone.. was out on the lake last weekend and noticed a not that loud but noticeable growling type noise when turning left or right. Everything sounds normal when going straight and when titlting the outdrive up and down.. it’s only left and right when it can be heard. Also noticed a slight vibration as well.. i know the typical bad gimble bearing noise is the growl but which do you think is bad? Also.. i bought this boat last September and dont know when the outdrive was last greased but the bellows are only a year old.. maybe its that or low power steering fluid that could maybe cause this too?


Just when i think im gonna have a problem free summer this happens.... sigh! :facepalm:


Note: 1990 mercruiser 4.3 alpha one drive

 

[Mad Props]

Sounds like U-joints... Typically only make noise under full steer one way or another. If this boat is new to you, then its probably time to pull the drive (10 minute job) and inspect both gimbal bearing and u-joints, as well as change the impellar if its not been done recently. Also, you will be able to make sure theres no water in the u-joint bellows which can cause them to fail quickly.

 

[Wellcraft170]

Sounds like U-joints... Typically only make noise under full steer one way or another. If this boat is new to you, then its probably time to pull the drive (10 minute job) and inspect both gimbal bearing and u-joints, as well as change the impellar if its not been done recently. Also, you will be able to make sure theres no water in the u-joint bellows which can cause them to fail quickly.

Thanks for the quick response.. here’s thing, i have a reliable family friend mechanic who about 3 weeks ago just changed the impeller and exhaust bellow because it slipped off the clamp and he took the outdrive off to put new seals on and what not.. so wouldn’t he have noticed if the ujoints or gimble was bad?

 

[Mad Props]

If he specifically checked those items then yes, he would have seen it. But do you know for a fact those were checked? U-joints most likely won't be visibly bad and there isn't really a good way to check them other than look to see if they got wet and are rusty. The gimbal bearing you can usually spin with two fingers and feel for rough spots or grinding (If it doesn't, this doesn't necessarily mean its good, sometimes bearings need a load on them to make noise).

Point being, I would start by checking the gimbal bearing by hand and if it tests fine, I would replace the u-joints. But to be honest, if it were me, I would probably consider just changing both u-joints AND gimbal bearing just for piece of mind... Neither are that expensive.

 

[Wellcraft170]

If he specifically checked those items then yes, he would have seen it. But do you know for a fact those were checked? U-joints most likely won't be visibly bad and there isn't really a good way to check them other than look to see if they got wet and are rusty. The gimbal bearing you can usually spin with two fingers and feel for rough spots or grinding (If it doesn't, this doesn't necessarily mean its good, sometimes bearings need a load on them to make noise).

Point being, I would start by checking the gimbal bearing by hand and if it tests fine, I would replace the u-joints. But to be honest, if it were me, I would probably consider just changing both u-joints AND gimbal bearing just for piece of mind... Neither are that expensive.

Gotcha.... what would be the ballpark for just a ujoint change by itself, just a gimble bearing by itself and both?

 

[tpenfield]

$600 for both. Maybe $400 each separately

 

[Wellcraft170]

$600 for both. Maybe $400 each separately

Any chance at all that low power steering fluid and lack of grease in the drive would cause this or no?

 

[harringtondav]

I'd go with $150 - $160 for both U joints if you buy Merc heavy duty, which I would. Auto/truck U joints can be found that fit the yokes, but have wimpy small trunions compared to real marine U joints.

Merc sealed gimbal bearing: $108. I prefer the Sierra 18-2100 ($44), which is the same Link Belt bearing. I like this one because it is greaseable, like your '90 drive has. If you use this one, be sure to find the grease hole under the tolerance ring, and line it up with the grease supply hole in the gimbal bore. The sealed Sierra is 18-21001, $58. It will come with a pipe plug to replace the grease Zerk.

PS, I couldn't find an Alpha drive for 1990. If it's an Alpha One, ending in 1989, my numbers are crap. If it is a Gen II, they're good.

Also, I'm not there to hear the noise, but if it's not too bad, you may be able to put this off until after season. Give the gimbal brg a good greasing at the zerk. Then back off the power on turns. If the racket gets worse, put the boat on the trailer. If not, you've got a good winter project.

 

[Wellcraft170]

I'd go with $150 - $160 for both U joints if you buy Merc heavy duty, which I would. Auto/truck U joints can be found that fit the yokes, but have wimpy small trunions compared to real marine U joints.

Merc sealed gimbal bearing: $108. I prefer the Sierra 18-2100 ($44), which is the same Link Belt bearing. I like this one because it is greaseable, like your '90 drive has. If you use this one, be sure to find the grease hole under the tolerance ring, and line it up with the grease supply hole in the gimbal bore. The sealed Sierra is 18-21001, $58. It will come with a pipe plug to replace the grease Zerk.

PS, I couldn't find an Alpha drive for 1990. If it's an Alpha One, ending in 1989, my numbers are crap. If it is a Gen II, they're good.

Also, I'm not there to hear the noise, but if it's not too bad, you may be able to put this off until after season. Give the gimbal brg a good greasing at the zerk. Then back off the power on turns. If the racket gets worse, put the boat on the trailer. If not, you've got a good winter project.

The boat is a 1990 but i assumed this motor was too.. might be an 89’ for all i know.. it is a gen 1 though not gen 2

also.. now that im thinking about it, the noise was really only there when in no wake zones not at full speed.. i asked above but ill ask you as well, is there any chance low power steering fluid and lack of grease in the drive could cause this?

 

[harringtondav]

The boat is a 1990 but i assumed this motor was too.. might be an 89’ for all i know.. it is a gen 1 though not gen 2

also.. now that im thinking about it, the noise was really only there when in no wake zones not at full speed.. i asked above but ill ask you as well, is there any chance low power steering fluid and lack of grease in the drive could cause this?

Those are easy things to check, and adjust. Low power steering fluid normally causes a whine in the engine compartment. If the noise is from low drive lube or gimbal brg. grease, you may quiet it down a bit by topping it off, but something probably has been compromised, and will eventually shut you down. If it's from worn out U joints, same end game. So, again, top off everything and pay attention to your drive's noise. But if it increases, pull your drive and check things per above. If you have to be pulled back to the ramp, my $$$ est will be rounding error.

 

[Rick Stephens]

No such thing as a “marine u-joint”. They are made by standard automotive manufacturers and purchased by Merc, No reason not to use Cross over u-joints.

When u-joints make noise you just replace them. They may even feel fine. Losing one is bad.

 

[Scott Danforth]

agreed, no such thing as a "marine u-joint"

I believe that Don S has a cross-reference in the stickies for all the U-joints to standard spicer or gkn part numbers


edit: verified....see stickies, link 22

 

[harringtondav]

No such thing as a “marine u-joint”. They are made by standard automotive manufacturers and purchased by Merc, No reason not to use Cross over u-joints..

I've had this discussion often with others, and I still hold my ground. The trunion OD on the Merc and the Sierra aftermarket is .700". Cross reference Spicer and other's HD M (for marine) is .600" OD. That is 15% less needle bearing area. Machine design engs. resolve higher radial/side loads w/larger bearings. So I put my trust in the Merc. enginneers.

You can save $70 on a pair of auto/truck U joints, but for the time and effort for a re-do, or worse carnage, I consider $70 a bargain.

 

[Wellcraft170]

Update:

greased up the drive and used it yesterday all day and the noise went away but literally as i was waiting to pull it out at the launch, hard over left and right you can hear a rattle/marble sound so its time to get it looked at and fixed. The rattling/marble sound is more so the ujoints or gimble? Im getting it fixed regardless but just want to know which sound that is for future reference

 

[tpenfield]

U-joints

 

[Wellcraft170]

Thought so.. thanks for the quick responses, much appreciated

U-joints