Split Motor Coupling Removal

[a_braley]

New to me 2003 Pacific Trawler has the original (22 year old) Tides Marine dripless shaft seal which I plan to replace. Shaft is coupled to motor with what I believe is a Buck Algonquin split coupler. Coupler is rusted (photo) and I am expecting a challenge getting it separated from the shaft. I have read as much information on this forum about flange/coupler removal as I could find and it is much appreciated. I took note of one post that suggested setting a time limit for removal and once that is exceeded start cutting with an angle grinder. I will bring my angle grinder with me when I head to the boat in a couple weeks.

Several posts talk about refacing the coupler flange while it is mounted on the drive shaft. This is not possible for this boat since even if the motor were out of the boat there is not adequate space between the forward engine room bulkhead and the shaft tube to install the shaft from inside the the boat. I am thinking that if the flange was faced and installed with the shaft during construction of the boat this would have had to be done early in the build prior to bulkhead installation.

I am hoping that if I am able to remove and reinstall the existing coupler that there will not be a great enough change in the alignment of flanges to cause me problems. If I have to destroy the existing coupler during removal and replace it with new that may be a different story.

Wondering if others have removed and reinstalled the motor coupler without having the flange refaced without issues?

 

[luna]

I am sure that with a few steel wedges and a 24 oz. mallet you will enlarge the coupler's bore to allow easy removal of the coupler from the shaft. If not, a puller and some heat will certainly do the job.

When you have your coupler "faced" to the shaft it is done with the shaft in the machine shop mounted in a large lathe. The coupler is mounted on the straightened shaft, marked as to it's orientation and machined so that the face of the flange that you bolt to the gear's output flange is 90º to the shaft's centerline. The coupler is then taken off of the shaft and it's all shipped back to you.
It's up to you to put it back together, aligning the index marks correctly.

Any time my shaft is in the machine shop, the coupler is faced once it is mounted on the straightened shaft. My unsplit coupler has been faced 4 times in almost 30 years. I'm likely good for another 30.

If the coupler is removed and the shaft is left in place (to install new lip seals) as long as I put the coupler back on the shaft with the index marks aligned, all is good.

One final thing. If I was to have to set a time period where once exceeded I would take the grinder out and cut the split coupler off, the time period would be a year.

 

[a_braley]

Thanks for the information and explanation.

I am assuming that if I can loosen the split coupler and remove the shaft that I will be able to slide it back together without using too much force. I will index the shaft to the coupler to get back as close as I can to the original position.

 

[Comodave]

I made a coupler removal tool that worked very well for me when getting the coupler off the shaft. Basically a flat piece of steel with holes drilled into it that line up with the holes in the coupler. Then you loose assemble it to the coupler with a socket in between the plate and the end of the shaft. Then tighten up the bolts in turn and the socket will press out the shaft. Sorry about the extra photo of the shed under construction, it attached by mistake and I couldn’t get rid of it.

 

[luna]

Typically if you are still in the water when you do this, you can:

- Put a shaft zinc on the shaft inside the boat so that you don't lose the shaft into the lip seal carrier before it hits the rudder.

- Split the coupler with some wedges.

- Remove the bolts connecting the Shaft coupler to the gear's output flange.

- Remove the Shaft coupler, as it should be quite loose. Use a strap wrench to slowly spin the shaft and it will travel downhill.

- Remove the shaft zinc and whatever else you plan on removing. Be careful not to lose the shaft.

- Have lots of diapers available, for you, not the boat!

Installation is as they say, the reverse of removal, although you may need a large C clamp or some threaded rod & nuts to pull the coupler up to the gear's output flange.

Out of the water is about the same procedure, although no diapers are required.

You also need to ensure that you apply the finish to the shaft in the area where the lip seals ride, exactly as defined by the seal provider.

 

[a_braley]

I made a coupler removal tool that worked very well for me when getting the coupler off the shaft. Basically a flat piece of steel with holes drilled into it that line up with the holes in the coupler. Then you loose assemble it to the coupler with a socket in between the plate and the end of the shaft. Then tighten up the bolts in turn and the socket will press out the shaft. Sorry about the extra photo of the shed under construction, it attached by mistake and I couldn’t get rid of it.

Thanks for the photo. I plan on making plate like this later today just in case the shaft does not come loose after I drive some wedges into the split coupler. I was able to find a 3d drawing files for my twin disk transmission here:
MG-5050SC - Twin Disc (see installation drawing tab). Will use this drawing of the transmission output flange to fabricate the plate since the boat is 365 miles away.

 

[a_braley]

Typically if you are still in the water when you do this, you can:

- Put a shaft zinc on the shaft inside the boat so that you don't lose the shaft into the lip seal carrier before it hits the rudder.

- Split the coupler with some wedges.

- Remove the bolts connecting the Shaft coupler to the gear's output flange.

- Remove the Shaft coupler, as it should be quite loose. Use a strap wrench to slowly spin the shaft and it will travel downhill.

- Remove the shaft zinc and whatever else you plan on removing. Be careful not to lose the shaft.

- Have lots of diapers available, for you, not the boat!

Installation is as they say, the reverse of removal, although you may need a large C clamp or some threaded rod & nuts to pull the coupler up to the gear's output flange.

Out of the water is about the same procedure, although no diapers are required.

You also need to ensure that you apply the finish to the shaft in the area where the lip seals ride, exactly as defined by the seal provider.

Thanks for the tips. I particularly like your comment that the coupler should be quite loose once I use some wedges. The boat is out of the water as required by my insurance. My port is Valdez, AK where is snows a lot. My "caretaker" sank my last boat for lack of shoveling. The same year several other boats were sunk tied to their moorings and the insurance companies are understandably cautious about boats over wintered in the water.

 

[a_braley]

Typically if you are still in the water when you do this, you can:

- Put a shaft zinc on the shaft inside the boat so that you don't lose the shaft into the lip seal carrier before it hits the rudder.

- Split the coupler with some wedges.

- Remove the bolts connecting the Shaft coupler to the gear's output flange.

- Remove the Shaft coupler, as it should be quite loose. Use a strap wrench to slowly spin the shaft and it will travel downhill.

- Remove the shaft zinc and whatever else you plan on removing. Be careful not to lose the shaft.

- Have lots of diapers available, for you, not the boat!

Installation is as they say, the reverse of removal, although you may need a large C clamp or some threaded rod & nuts to pull the coupler up to the gear's output flange.

Out of the water is about the same procedure, although no diapers are required.

You also need to ensure that you apply the finish to the shaft in the area where the lip seals ride, exactly as defined by the seal provider.

Wondering if the coupler should be removed from the output flange to protect the transmission before driving the wedges to loosen the split coupler ? If this is not a concern then it is easier to use the wedges while the shaft is still bolted to the output flange.

 

[lwarden]

I have the same transmission and coupler on my boat. I don't think you will have a lot of issue getting it off. Go easy on driving wedges into the spilt since too much force and distort the coupler and throw off the perpendicularity of the face.
The comment about cutting it off sounds like one I would have probably made. This goes for the non-split ones which can be a real bear to get off and not for the split type that come off pretty easily. Also, since you are not going to be able to pull the shaft you would not be able to fit the new coupler and face it properly, so that comment does not apply. And yes, you will want to remove the coupler from the output flange before trying to remove it.

 

[luna]

I agree with lwarden, unbolt the coupler from the tranny's output flange before tapping (not hammering) in the wedges to split the coupler.
My original sequence was not the way I would actually do the job. Free the tranny first.

 

[a_braley]

Came apart fairly easily as you described Luna. Thanks again