How to remove the shaft coupling

[RodrigoDC]

Hello, I'm trying to replace the stuffing box for a dripless system.

Any ideas how to remove the shaft coupling in order to remove the box, nut and hose?

Please refer to the picture. As you can see, there is no room to pull out the coupling away from the shaft without removing the transmission first.

Thanks in advance for your input.

[stormalong]

Put a nut with an overall outside diameter that is smaller than the shaft diameter between the coupling and the transmission. Use longer bolts to draw the coupling up to the transmission. Repeat with more nuts until the shaft if ejected from the coupler.

BUT do not draw too tight. If the shaft does not move soak it in penetrating oil (liquid wrench, etc.), wait for it to work and try again. If that does not work you can try heating the coupler with a propane torch using a heat shield between the coupler and the hull.

[Startracker]

Originally Posted by RodrigoDC

Hello, I'm trying to replace the stuffing box for a dripless system.

Any ideas how to remove the shaft coupling in order to remove the box, nut and hose?

Please refer to the picture. As you can see, there is no room to pull out the coupling away from the shaft without removing the transmission first.

Thanks in advance for your input.

Get some fine thread bolts and nuts of the same diameter as your original bolts, but 1/2" longer, as well as a pile of washers. This massively increases your pressing power and controllability.
Find a pair of sockets just a hair smaller than your driveshaft diameter, a deep socket and a shallow socket.
Start with the shallow socket, and as many washers as you need on the bolts to get it pressing. Press until the coupling almost touches, add more washers, repeat until it is pressed the fulll depth of the socket. Now repeat the process with the deep socket. If still not out, repeat again with the shallow socket in first and then the deep socket after it.
This has worked on up to 3" shafts for me.

[markxengineerin]

I just did this job, and after deciding to remove the transmission, it ended up being laughably easy compared to what I was expecting. 45 minutes of work and trans was out, puller on the shaft. I put reasonable pressure on the puller, it was going nowhere, so heated it with map gas and it finally popped.

I could not use the trick suggested above because of the rubber elements in the "drive saver coupling".

[Bill Seal]

Please refer to the picture. As you can see, there is no room to pull out the coupling away from the shaft without removing the transmission first

His problem seems to be that the coupling is about 1.5" long, but there's only 1" gap. Unless he can slip the shaft back another inch, there's no room to get it out.
Hopefully, even if he tries to pull the trans, he'll have enough room to get the spline out of the flex plate without having to move the engine foreward.

[RodrigoDC]

Thank you, both are great ideas worth trying. But perhaps I did not explain myself well, or I'm not understanding what will happen once I begin to draw the coupling away from the shaft.

Look at the distance between the coupling and the transmission. Clearly, the coupling will not fit even if I draw it out all the way to the transmission. Does that make sense?

Will the shaft move aft as I draw the coupling towards the transmission?

[Startracker]

Originally Posted by RodrigoDC

Thank you, both are great ideas worth trying. But perhaps I did not explain myself well, or I'm not understanding what will happen once I begin to draw the coupling away from the shaft.

Look at the distance between the coupling and the transmission. Clearly, the coupling will not fit even if I draw it out all the way to the transmission. Does that make sense?

Will the shaft move aft as I draw the coupling towards the transmission?

You are actually driving the shaft out of the coupling, not pulling the coupling off the shaft. Also, you can cut the hose first if needed. But you better be sure you're going to get it out then!

This assumes of course that you have sufficient clearance between the propeller and rudder. If not, you may find that removing the propeller first, and turning the rudder hard over gives the clearance, this depends on the boat.
If it doesn't move with a reasonable tension, give it another bit more tension, and then heat along the keyway side if the shaft has a key with a MAP not propane torch. Keep fingers well clear, often it will let go in a hurry with heat, seem someone have a very bad day on a 3' prop by getting his ex-fingers in the way. They are his ex fingers because they were turned into paste.

[boatpoker]

Cut it off with a disc grinder and replace it with a split coupling.
I had the same situation and could not slide the shaft back far enough without dropping the rudder. This worked out well and was pretty easy.

https://www.generalpropeller.com/RD-Split-Couplings

[Startracker]

Originally Posted by boatpoker

Cut it off with a disc grinder and replace it with a split coupling.
https://www.generalpropeller.com/RD-Split-Couplings

Definitely second this, if your bank account can handle it! A quick cut down the side with a diamond disk and press off still.
The one risk with the pressing straight off method is that you put too much pressure on something in the transmission. I have seen a transmission coupling that had to be re machined and a seal replaced because the owner was too enthusiastic on one side and then added a hammer to the mix.

[Knotical]

Originally Posted by boatpoker

Cut it off with a disc grinder and replace it with a split coupling.
I had the same situation and could not slide the shaft back far enough without dropping the rudder. This worked out well and was pretty easy.

https://www.generalpropeller.com/RD-Split-Couplings

I doubt this will work, split couplings are longer than traditional ones and he doesn’t have much room there for it, I know because I had the same problem.

To the OP - I cut the coupling with an angle grinder and installed a new one.

[boatpoker]

Originally Posted by Knotical

I doubt this will work, split couplings are longer than traditional ones and he doesn’t have much room there for it, I know because I had the same problem.

To the OP - I cut the coupling with an angle grinder and installed a new one.

There are several different manufacturers and designs all with different dimensions, like everything else one has to research. Sorry it didn't work for you but it did for me.

[nuku34]

The OP states he wants to replace the stuffing box with a dripless type. Has he measured to see if the usual PSS dripless seal will actually fit in that very tight space?
Also the "socket and bolts" method of forcing the prop shaft out of the coupling can crack the flange on the transmission if you are not very careful. That's big $'s and hassle to replace. If you use that method, apply heat, penetrating oil and take up slowly on the bolts. Do NOT use a hammer. It may take a day of slowly tightening the bolts before the coupling "pops". If it doesn't move, then cut it off with a grinder.

[fourlyons]

Originally Posted by RodrigoDC

Thank you, both are great ideas worth trying. But perhaps I did not explain myself well, or I'm not understanding what will happen once I begin to draw the coupling away from the shaft.

Look at the distance between the coupling and the transmission. Clearly, the coupling will not fit even if I draw it out all the way to the transmission. Does that make sense?

Will the shaft move aft as I draw the coupling towards the transmission?

Yes, the shaft will move aft and give you clearance. The question is how far aft can the shaft move before hitting the rudder.

[DougR]

Sometimes with a drop center transmission it’s possible to remove the bolts that hold the transmission to the flywheel housing and rotate the transmission around it’s input shaft 90 degrees to port or starboard. This moves the gearbox flange sideways out of the way of the prop shaft coupling and allows the shaft coupling to be moved forward off the shaft.

[sailcrazy]

Following. My PYI Bellows is now 7 years old, so this project is in my future!