Removing shaft coupling from tranny

kito

kito

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Sep 13, 2012
2,011
1979 Hunter Cherubini 30 Clemmons
I am hoping someone can help me out. I removed the 4 bolts, took off the stuffing box hose and the shaft won't budge. The coupling is corroded and I'm sure it has a pilot diameter that fits in the tranny coupler. I sprayed it down with PB Blaster too. Is there something I am missing?. It should just pull off.....correct? I even tried a wedge at the connection and taped around it. I thought I would go ahead and do this in preparation for my new motor mount installation
 
kloudie1

kloudie1

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Nov 6, 2006
10,058
Hunter 34 Mandeville Louisiana
Yup, should back off the face of the transmission half. Might be bound on the pilot fit or centering fit ring inside the bolt circle.. after letting the PB Blaster soak a couple of days, try tapping and rotating as you tap. It has to go aft about 3/32" before it will release. be careful with a wedge so ya don't deform the transmission half. move the wedge as you rotate.
If you are out of the water, check that the shaft is not bound on a "wear shoulder" back at the cutless bearing
 
knot smart

knot smart

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Feb 8, 2013
92
beneteau 352 Raritan Bay
This might sound a little unethical but you may want to consider it ..now that you have the 4 bolts removed, start the motor and throw it in the forward or reverse for just a moment to break the seal ..then the whole shaft will slide to the aft where you then need to remove an inner nut & ultimately the hub itself which may require a puller.. I've sheared that key way more times than I'd like to admit
 
kito

kito

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Sep 13, 2012
2,011
1979 Hunter Cherubini 30 Clemmons
I considered that. I may try it if the pb Blaster doesn't do the trick. I assume the shaft is not tapered on the coupling end? Just a straight keyway and flats cut on the shaft for the anti-rotation screws on the coupling? Those two screws are going to be a big problem since the corrosion is bad. I believe it hasn't been removed since it was put together in 1979. I also figured that it would break loose when I take off the motor mount nuts and start jacking it up. I would rather not do that though in case it doesn't break loose :). Another question.....is it normal for the shaft to turn by hand when in gear? It doesn't turn as freely than in neutral. Just wondering if I have more issues to deal with. I haven't had this boat in the water yet. The shaft does turn when running and in gear. I am on the hard so didn't turn it very long.
 
jibes138

jibes138

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Jan 27, 2008
3,086
ODay 35 Beaufort, NC
kito said:
I considered that. I may try it if the pb Blaster doesn't do the trick. I assume the shaft is not tapered on the coupling end? Just a straight keyway and flats cut on the shaft for the anti-rotation screws on the coupling? Those two screws are going to be a big problem since the corrosion is bad. I believe it hasn't been removed since it was put together in 1979. I also figured that it would break loose when I take off the motor mount nuts and start jacking it up. I would rather not do that though in case it doesn't break loose :). Another question.....is it normal for the shaft to turn by hand when in gear? It doesn't turn as freely than in neutral. Just wondering if I have more issues to deal with. I haven't had this boat in the water yet. The shaft does turn when running and in gear. I am on the hard so didn't turn it very long.
Click to expand
a lot of boat recommend putting in gear when sailing so it doesn't turn . So I think the answer is it shouldn't turn in gear .
 
kito

kito

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Sep 13, 2012
2,011
1979 Hunter Cherubini 30 Clemmons
I know my inboard ski boat shaft wouldn't turn when in gear. My Yanmar's shaft will turn by hand but it's not easy. I thought maybe it has a clutch that requires rotation to engage. I added a few pics. I am not sure what I got into. Check out the shaft log where the stuffing box hose connects to......looks like a through hull fitting. He clamped to the threads and added sealant. The more I work on this project the further I get from completion.
 

Attachments

knot smart

knot smart

.
Feb 8, 2013
92
beneteau 352 Raritan Bay
kito said:
I considered that. I may try it if the pb Blaster doesn't do the trick. I assume the shaft is not tapered on the coupling end? Just a straight keyway and flats cut on the shaft for the anti-rotation screws on the coupling? Those two screws are going to be a big problem since the corrosion is bad. I believe it hasn't been removed since it was put together in 1979. I also figured that it would break loose when I take off the motor mount nuts and start jacking it up. I would rather not do that though in case it doesn't break loose :). Another question.....is it normal for the shaft to turn by hand when in gear? It doesn't turn as freely than in neutral. Just wondering if I have more issues to deal with. I haven't had this boat in the water yet. The shaft does turn when running and in gear. I am on the hard so didn't turn it very long.
Click to expand
On my 99 bene 352 it's tapered..I wouldn't mess with the motor mounts, the angle of the motor is crucial so there isn't stress on coupling(probably wear out trans bearing if off)..hmm.. not sure if it should turn while in gear.. I wouldn't think so, but I can't recall ever trying that
 
kito

kito

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Sep 13, 2012
2,011
1979 Hunter Cherubini 30 Clemmons
I am sure that the motor mounts are original so I am replacing anyway. I hope someone will chime in about the shaft turning while in gear. It's hard to turn by hand but noticed it turned when putting a wrench on the coupling nuts. I hope I don't need to tear into the tranny now............
 
kito

kito

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Sep 13, 2012
2,011
1979 Hunter Cherubini 30 Clemmons
Woodster, the boat is on the hard and I believe this tranny hasn't seen work in at least 10 years. I got the engine running great now and yes, the engine/tranny turned the prop shaft in forward and reverse but under no load. I didn't run it in gear very long since the stuffing box and cutlass bearings were dry and was squealing a bit. I am hoping it's just a friction disc issue since it's not been run for a while. Maybe there is a glaze on the plates from sitting idol. If anyone with a Yanmar (ysm12) wants to go for a swim and try to turn the prop while in gear, I got a cold beer for ya. :)
 
woodster

woodster

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Sep 15, 2009
6,243
S2 9.2a Fairhope Al
more than likely it will work ....just don't use a slide hammer puller on removing the shaft it will pull on the tranny parts too....maybe take a 2 lb brass hammer and turn the shaft and tap on the shaft side of the coupling while you rotate it
 
S

svchickadee

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May 8, 2011
189
ODay 25 Cambridge
Get 4 long bolts/nuts and some pipe fittings of various lenghts. Put the bolts thru both the transmission and coupler with the pipe fitting against the shaft and tighten. This will drive the shaft back out the coupler. Takes a while but I did this on my Perkins 4-154 and it works. Use a rubber mallet to whack the coupler after tightening the bolts and it will give.
 
kito

kito

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Sep 13, 2012
2,011
1979 Hunter Cherubini 30 Clemmons
Thanks Woodster. After I free the coupling then I can run it and test out the tranny better. The stuffing box issue I have that is shown in the photo I posted earlier really concerns me too. Is this a typical fix for a bad stern tube/shaft log?. Clamping a hose to a threaded thru hull fitting seems like a jeri rig job. I just want to do this right. Btw, the info I received here during my restoration has been extremely helpful.
 
kito

kito

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Sep 13, 2012
2,011
1979 Hunter Cherubini 30 Clemmons
svchickadee said:
Get 4 long bolts/nuts and some pipe fittings of various lenghts. Put the bolts thru both the transmission and coupler with the pipe fitting against the shaft and tighten. This will drive the shaft back out the coupler. Takes a while but I did this on my Perkins 4-154 and it works. Use a rubber mallet to whack the coupler after tightening the bolts and it will give.
Click to expand
Thanks for the tip but still scratching my head. Not sure what you mean about "pipe fittings".....you talking about different length pipe nipples?
 
Chris Patterson

Chris Patterson

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Oct 17, 2011
2,809
Ericson 29 Southport..
Koto, what ever you do, do not spray PB Blaster on that rear transmission seal. Seals and gaskets will deteriorate quickly with the stuff by it's very nature.

And I have seen a bunch of stern tubes, but none like that. It seriously does look like a thru hull. Mm,mm..
 
kloudie1

kloudie1

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Nov 6, 2006
10,058
Hunter 34 Mandeville Louisiana
Kito, the transmission will turn by hand when in gear. It should be more difficult to turn in one direction than the other but you may be able to turn it by hand . The transmission locks when the engine drives it.
 
kito

kito

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Sep 13, 2012
2,011
1979 Hunter Cherubini 30 Clemmons
Chris Patterson said:
By the way Kito, where is that boat lying?
Click to expand
Chris, it's in my backyard in Clemmons NC. It makes it convenient to work on but I bet my neighbors will be happy to see it finished :)
After looking at the funky shaft log again, it is indeed a 1-1/2" bronze thru hull fitting. He added 2 screws to the outside flange so it wouldn't rotate if there is any friction between the shaft and the stuffing box and tries to turn the nipple. Looks like a good idea except for using the threads as a barbed nipple. I am going to try to get the coupler free and shaft removed today. Looks like I will need to cut a groove in my skeg to get it out though. If anyone knows where I can find a replacement stern tube shaft log, please point me in the right direction. I would rather do this right.
 
Anonymous 121765

Anonymous 121765

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Jan 6, 2010
1,520
Kito,

Still working your projects I see. I assume there is no way to change out the mount with the flanges in place?

If in the boat yard, ask if they have a shaft puller (I believe you can rent them as well). Just remove the prop & attach the puller. It has a slide weight that you can use. It doesn't have to be slid real hard, it's the shock/vibration that will loosen the coupler flange. Make sure you tighten the flange setscrews to the shaft first. If they look too rusty, replace them with new bolts. Be careful not to snap the old ones off.

I've seen this do one of two things, it will either separate the coupler flanges or pull the shaft from the flange.

Not too hard on the shaft puller, as you don't want to put too much strain on your tranny flange & transmission shaft. It's the quick shock & frequency wave that does it all.

CR
 
kito

kito

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Sep 13, 2012
2,011
1979 Hunter Cherubini 30 Clemmons
CR, I will look into a shaft puller because I am dead in the water on this project without getting that darn coupler loose. I tried tapping a wedge between the two flanges and it's like they are welded together. I put a clamp on the shaft coupler so it would wedge to the floor and then turned the prop by hand with some quick hard turns and still no go. The shaft screws aren't going anywhere either. They will have to be cut flush and drilled out. I just can't get enough leverage in that tight space. Thought about applying heat but would destroy any seals close by, plus all the PB Blaster I used would probably catch fire :). Very Aggravating
 
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