Another Post about U-Joints and Gimble Bearing replacement help

[subysti]

OK I know this topic has been beat to death but I cannot seem to find this info on any other posts. I think I need to replace my U-joints. I'm guessing its this because the gimble bearing was replaced last year at the dealer. Anyways.. the problem is a vibration at low rpms when going straight but goes away at higher speeds. When turning its a vibration and a grumbling noise at slower speeds. All the bellows and gimble bearing were replaced last year so there shouldn't be any water intrusion problems andnothing comes out when the plug is removed. My questions are 1, after looking at all the vids and manuals I believe I can replace the U-Joint assembly by just removing the outdrive and not having to fiddle with bellows and gimble housing correct? 2nd can I replace the gimble bearing the same way or do I have to remove the bellows and gimble housing to get it out? Do I need the engine alignment tool? some say yes others only if the engine is moved. I'm going to replace the entire U-Joint assembly just because I think it will be better to do it as a complete unit.

I'd even be willing to pay to have someone local train me do it so I can learn the procedure.

I have a 1996 5.7 merc with an Alpha Gen II drive.
Thanks for any advise..

 

[subysti]

Re: Another Post about U-Joints and Gimble Bearing replacement help

No one? Anyone?

 

[mkast]

Re: Another Post about U-Joints and Gimble Bearing replacement help

When was the last time the engine alignment was checked?
When you remove the stern drive the universal joints have a tendency to follow. When the drive is removed, you can inspect the bellows and gimbal bearing. When was the lower shift cable replaced?
You might want to look at the maintenance manual.

 

[subysti]

Re: Another Post about U-Joints and Gimble Bearing replacement help

last year I had a leaking shift cable bellows so all the bellows were replaced as well as the gimble bearing and shift cable. At least thats what the dealer told me they did and what I paid for.

 

[PitchFork]

Re: Another Post about U-Joints and Gimble Bearing replacement help

I replaced my gimble bearing last week and the growling noise went away, but a vibration was still there. I purchased a set of u-joints off eBay and will be replacing them tonight. I made an alignment bar at work last week on our CNC Lathe out of Cold Roll Steel. I would recommend you to get one. On eBay I have seen them as low as $50. The reason is if you pull the drive and hit or move the gimble bearing the drive will not go back on. The spline shaft will not line up with the engine. Replacing the bearing was a lot easier than I thought and glad I learned how to do it. The backlog at most shops around here are 2 to 3 weeks as the lake here is at Summer Pool for the first time in two years.
Make sure you put the shifter in full forward and have help to pull the drive off. It sounds like you have done a lot of research and if you are mechanically inclined you should have no problems changing the u-joints. Research! Research! is the name of the game.

 

[subysti]

Re: Another Post about U-Joints and Gimble Bearing replacement help

i thought the alignment tool was only needed if the engine was moved.

 

[bruceb58]

Re: Another Post about U-Joints and Gimble Bearing replacement help

The engine can still move on its own due to motor mounts getting compressed with age and the boat stringers themselves getting compressed with age. It doesn't take much for an engine to be out of alignment...fractions of an inch.

 

[subysti]

Re: Another Post about U-Joints and Gimble Bearing replacement help

and what would be required to align the engine? I hope not moving the engine is involved.

 

[bruceb58]

Re: Another Post about U-Joints and Gimble Bearing replacement help

You adjust the height of the front engine mounts. Its a pretty easy task.

 

[bruceb58]

Re: Another Post about U-Joints and Gimble Bearing replacement help

1) Once you have the engine height close enough to
fully insert the tool without force, then you can start
working on setting the proper alignment.

Take your time, getting it close enough to insert the
tool the first time can sometimes be the hardest (most
frustrating) part.

2) Coat the end section of the tool (the smallest diameter
area) with a light coat of grease and then insert it fully
into the coupler.

3) Without turning the tool, pull it straight out and look at
the depth of the teeth marks in the grease.

If the teeth marks in the grease are deep on the
top side and shallow on the bottom side of the tool then
your motor is too high.

If the marks in the grease are deeper on the bottom than
on the top then your motor is too low.

4) Adjust the engine height accordingly.

5) Keep checking the depth of the marks in the grease until
they are equal in depth on top and bottom.

Sometimes as little as 1/8th of a turn on the adjusting nut can be the
difference between being properly aligned, and just having it "close"

Lightly Grease the splines on the shaft (and on the coupler if you can) with
Spline grease prior to assembly.

 

[subysti]

Re: Another Post about U-Joints and Gimble Bearing replacement help

Thanks everyone for all the help. It looks like i'm going to do a lot once its apart, gimble, u-joints, trim sender and limit and most likely the water pump impeller. Anywho, one last question, do I have to take off the gimble ring to get at the gimble bearing or can it be done through the gimble ring. If I have to remove the gimble ring then its a whole nother things to deal with like removing the exhaust bellows which I don't want to do because I don't have the expanders and such. thanks again.

 

[subysti]

Re: Another Post about U-Joints and Gimble Bearing replacement help

anyone?

 

[mkast]

Re: Another Post about U-Joints and Gimble Bearing replacement help

The ring isn't removed to replace the bearing.
Time to download the manual for your power package and start reading it.

 

[ken_23434]

Re: Another Post about U-Joints and Gimble Bearing replacement help

You can replace the gimbal bearing without pulling the gimbal ring. You just need to have a slide hammer with a long enough reach to get to the bearing.

Once the drive is pulled, you will be able to see inside the U-joint bellows and inspect it for any problems.

The u-joints are fairly simple to replace. The Mercruiser part is about $60 each, alternates can be found at Pepboys, Napa etc for about $10 each. I think in the Adult's only sticky, there is a link to a post with the part numbers of other manufacturers (I have personnaly used one of those part #'s, so I know that one at least works as an alternate)

No need to replace the whole shaft with the u-joints (unless something really strange has happened). A very large C-clamp (8" or bigger) along with a selection of sockets can be used to press the u-joints in and out. Otherwise, you can "borrow" the tools at some of the Auto stores using their "loaner tool" program.

Checking the engine alignment is just HIGHLY recommended whenever you have the drive pulled. There is nothing about pulling off the drive or replacing the gimbal bearing that would cause the engine to be out of alignment. But, as stated above, the engine might "shift" over time, so checking the alignment is just always a good idea. The engines alignment will be the exact same as it was before you pulled the drive, assuming you did not mess with the engine's mounts.


In case you did not know, at the "Adults Only Sticky" at the top of the forum, there is a link where you can download the official Mercruiser Service Manuals. The manuals for your engine/outdrive are a "must have". They are much better than the other brands you might find at the local boat store.

 

[TpaPaul813]

Re: Another Post about U-Joints and Gimble Bearing replacement help

A++ info....

 

[subysti]

Re: Another Post about U-Joints and Gimble Bearing replacement help

Thanks Ken that clears up everything. I do have the actual shop manual but it assumes you already know some things I think. Anyways thanks a lot again, I think this should save me about $1500 from the dealer.

 

[air man]

Re: Another Post about U-Joints and Gimble Bearing replacement help

Hi, A note from a newby,
I replaced the gimbal bearing on our boat(mercruiser) years ago. I was loaned the alignment tool and used it to set the alignment. When done 2 fingers would slide the tool into place. However - once the boat was put in the water and run, the drive rumbled badly. Adjusting the alignment helped. With some effort the rumble was adjusted to a minimal level though never was gone. I just pulled it apart this week. I found that the pivot pins had loosened up in the housings. This allows a chucking around of the lower unit resulting in misalignment of the drive to the gimbal bearing. You can check for this. With the unit lowered but not forced hard against the stops try grabbing the skeg and rocking the drive side to side and also vertically. The drive is heavy so it would take some effort but there may be some loosness noted in the pivots.
Ron

 

[air man]

Re: Another Post about U-Joints and Gimble Bearing replacement help

Hi, A note from a newby,
I replaced the gimbal bearing on our boat(mercruiser) years ago. I was loaned the alignment tool and used it to set the alignment. When done 2 fingers would slide the tool into place. However - once the boat was put in the water and run, the drive rumbled badly. Adjusting the alignment helped. With some effort the rumble was adjusted to a minimal level though never was gone. I just pulled it apart this week. I found that the pivot pins had loosened up in the housings. This allows a chucking around of the lower unit resulting in misalignment of the drive to the gimbal bearing. You can check for this. With the unit lowered but not forced hard against the stops try grabbing the skeg and rocking the drive side to side and also vertically. The drive is heavy so it would take some effort but there may be some loosness noted in the pivots.
Ron

 

[TpaPaul813]

Re: Another Post about U-Joints and Gimble Bearing replacement help

thanxs for the heads up Ron...