PDA

View Full Version : Shaft Log Replacement


homer12
04-04-2013, 01:10 PM
I have a pretty worn looking shaft log and I need to replace it before it cracks and I get big problems. My shaft alignment seems pretty good right now and I'm not trying to tackle that any time soon.
If I disconnect the shaft coupler from tranny and pop off the flange, should I be able to just bolt it all back up without needing to do an alignment?

TRBenj
04-04-2013, 02:39 PM
I assume you mean "shaft log hose" and not the shaft log itself, which is made of brass and usually fiberglassed right to the boat.

Replacing the log hose will have no effect on alignment (only strut location and powertrain placement will)... but the fact that you said it "seems pretty good" means its probably overdue. Why you would try to avoid checking it while everything is apart is beyond me.

psychobilly
04-04-2013, 02:47 PM
There's a member that just completed this task. You may want to search for this topic... There's a coplete write up on this.

psychobilly
04-04-2013, 04:20 PM
Double Post because of the VERY SLOW internet here in the South China Sea.... Sorry....

homer12
04-04-2013, 11:58 PM
I guess what I meant by pretty good is that there is no gaps anywhere between the coupler flanges and get no vibration under power. For my knowledge, that would mean alignment is good to me, but maybe I'm missing something.
Yes, I did mean the shaft log hose, my bad. I've researching the shaft alignment in case that is necessary.

FrankSchwab
04-05-2013, 12:18 AM
Reseach done!

92363

But, yes, you should be able to bolt everything back together without affecting the existing alignment. But taking off the coupler and separating it from the shaft is a reasonably big job; spending an extra hour to line everything up while you're working on the shaft already seems like a really good choice to me.

FrankSchwab
04-05-2013, 12:39 AM
Oh, and you'll probably need to replace the packing once you pull the stuffing box off the propshaft. Order it with the other stuff - 3/16" for 1-1/8" shafts, 1/4" for 1" shafts.

TRBenj
04-05-2013, 12:29 PM
I guess what I meant by pretty good is that there is no gaps anywhere between the coupler flanges and get no vibration under power. For my knowledge, that would mean alignment is good to me, but maybe I'm missing something.
Yes, I did mean the shaft log hose, my bad. I've researching the shaft alignment in case that is necessary.

I assume you are looking at the 2 flanges when they are mated or bolted together? If so, that is meaningless, as those bolts can hide gross misalignment (1/4" +).

Misalignment will also not cause any vibration at speed. The excessive side loading of both the shaft within the strut and transmission internals will not cause any outward symptoms, save for uneven strut bushing wear and premature transmission failure. Nothing you can easily see or hear underway though.

homer12
04-05-2013, 01:13 PM
Thanks fellas! I'm now convinced that when I get it disassembled I'll be checking all the alignment now and making adjustments as necessary. Doesn't sound too difficult, but maybe just time consuming because of a learning curve.
I plan to replace the shaft log hose and repack the stuffing box and get the shaft alignment done. :toast:

FrankSchwab
04-05-2013, 01:37 PM
You have joined the path of wisdom, my son. Soon your latent MCOCD will be more powerful than you could imagine!

homer12
04-12-2014, 10:40 AM
So I got this started yesterday and having issues getting the coupler off the shaft (surprise, surprise :rolleyes:). At least 3 years ago the PO told me he had bent the shaft and had replaced it so this drivetrain have been taken apart before.
So far, I have put penetrating grease in it and tried with a 2-bolt puller to get it off. I have not wanted to use the transmission coupler as a press for fear of bending or breaking. Well, I've already broken a bolt with so much tension. What do you think for my next attempt - use heat and keep pulling or find from flat steel and make a 4-bolt plate to pull against? Here's some pics: You can see my homemade coupler wrench that worked pretty well. You can also see the bolt I snapped off.

mikeg205
04-12-2014, 10:51 AM
Couple has some corrosion as you see. Probably some corrosion on the inside as well. I wouldn't try to force it off too much. Spray some more penetrating oil... keep the tension on it. I would heat it, use penetrating oil and tap at it while under tension.

Is the key still look lined up straight?

Will probably take a be a few days before it gives way.

homer12
04-12-2014, 03:01 PM
Thanks Mike! Key looks to be in good shape and lined up fine in key slot.
When using heat can you cause harm using too much? I've got a torch I can use. Also, will it pop off or just gradually start sliding off under tension? I put a small Sharpie line on the shaft to see if I was making any progress at all.

Sent from my DROID RAZR using Tapatalk

mikeg205
04-12-2014, 03:07 PM
It will pop... had this trouble on a benz with wheels not coming off on rotation...

regarding heat... I would just heat the union of the coupler and shaft... some one else here had the same trouble - took a few days but it popped off... heating the union should help penetrating oil to get deeper...

Heat and tapping the coupler when under tension should break it loose - I am always amazed how a little corrosion will lock something up when there are tight tolerances.

Darn can't find the thread.

homer12
04-13-2014, 12:06 AM
Man, the more research I do leads me to more questions. Do most people heat the couplers in the oven to expand them to refit/reinstall them or just crank down on the nut real tight? Also, is it recommended to use some anti-sieze on the mating surface for future removal? thanks a ton for the help so far Mike.

19_Skier
04-13-2014, 08:44 AM
Looks like we were both dealing with the same issue yesterday! Thanks for the tip in my thread, if I have any success today will let you know, good luck.

mgs96ps
04-13-2014, 08:52 AM
Anyone ever deal with this type of flange? Of course I don't have a socket big enough to fit...but is that all it is and it slips right off? Reverse theads? Anyone know size? Thanks.

mgs96ps
04-13-2014, 09:00 AM
Here is the stamp on the outside.

mikeg205
04-13-2014, 09:29 AM
Your on the right track here's a thread I found somewhere else.

http://www.pbase.com/mainecruising/pss_shaft_seal

TOO-TALL
04-13-2014, 02:40 PM
Good read

homer12
04-13-2014, 03:37 PM
Mgs96ps, looks like there is a key slot on it so probably a tapered fit like mine. Although I don't see a key sticking out like mine...is it in there?

Sent from my DROID RAZR using Tapatalk

mgs96ps
04-13-2014, 04:15 PM
I chickened out. I had high hopes of changing out shaft log hose and stuffing box packing...but I just did stuffing box with it on prop shaft and plan on keeping an eye on hose.

mikeg205
04-13-2014, 04:50 PM
I chickened out. I had high hopes of changing out shaft log hose and stuffing box packing...but I just did stuffing box with it on prop shaft and plan on keeping an eye on hose.

I bet yours would come off pretty easily. next winter or the one after I will be tackling the shaft hose as well as the cutlass bearings.

homer12
04-15-2014, 12:42 AM
I tried heat and PB blaster and under pressure with the puller tonight. No success yet. Will keep the PB blaster happening and puller on it hoping it just takes time.

mgs96ps
04-15-2014, 12:48 PM
Mgs96ps, looks like there is a key slot on it so probably a tapered fit like mine. Although I don't see a key sticking out like mine...is it in there?

Sent from my DROID RAZR using Tapatalk

I'm not sure about the key. There is a nut on the end of prop shaft (transmission flange side) and a locking threaded insert perpendicular to it. Nut on end of shaft is over 1" and I did not have socket that was big enough to remove...so I gave up when I ran out of weekend. I hope MikeG is right that it will slide right off when end nut is removed. If someone knows for sure...that would be great.

homer12
04-15-2014, 03:15 PM
Just FYI - I have a 1" propshaft and the nut size on the end took a 1-1/4" socket.

TRBenj
04-15-2014, 07:55 PM
Yikes, terrible advice being offered!!!

The shaft to coupler is an interference fit. Penetrating lubricants and anti sieze are useless. So are half-assed pullers. You need to press it off, or admit defeat and cut the shaft with a sawzall. Use some bolts or threaded rods and an appropriate sized socket against the output shaft of the transmission. It'll come. Heat will help, but wont be enough. Definitely use heat/ice on the reinstall though.

homer12
04-16-2014, 03:51 PM
TRBenj, you are right, I've done enough additional reading to read about interference fit. It is different from tapered in the sense it is a straight shaft to straight coupling (slightly undersized) right? I have no way of pressing it still in the boat unless you're referring to pressing it against the socket.
Do you recommend using the tranny shaft coupler to press the socket on the shaft or using something else? I only have this to use for 2-bolts at the moment. Maybe it's time to get some thick plated steel and make a piece to press 4-bolts against.
I've been applying heat as well as light taps to the coupling to get it to come off. Been using mapp gas.

TRBenj
04-16-2014, 04:04 PM
Use the output coupler of the transmission to press the shaft out of the coupler. Use all 4 bolts and an appropriately sized socket. This is the tried and true method.

Or, if you know the shaft is bent, just cut it out with a sawzall and save yourself the hassle.

homer12
04-16-2014, 04:15 PM
I don't have any reason to suspect the shaft being bent. I think I'm going to take it to a machine shop though and have it checked and trued if they determine it needs it. So, no worries on bending or breaking the transmission output coupler? Just makes me nervous is all....

mikeg205
04-16-2014, 04:22 PM
Yikes, terrible advice being offered!!!

The shaft to coupler is an interference fit. Penetrating lubricants and anti sieze are useless. So are half-assed pullers. You need to press it off, or admit defeat and cut the shaft with a sawzall. Use some bolts or threaded rods and an appropriate sized socket against the output shaft of the transmission. It'll come. Heat will help, but wont be enough. Definitely use heat/ice on the reinstall though.

Interesting comment... since the coupler was not put on with a shop press. The corrosion on the that coupler. I get the interference fit - but the couple does not need that much pressure to move it. Also using the trans flange can yield in a very costly repair of the shaf tis seized up.

It should come of fairly easily - it was designed to do so... any corrosion on the interference fit will lock it up even tighter.

19_Skier
04-16-2014, 05:10 PM
Interesting comment... since the coupler was not put on with a shop press. The corrosion on the that coupler. I get the interference fit - but the couple does not need that much pressure to move it. Also using the trans flange can yield in a very costly repair of the shaf tis seized up.

It should come of fairly easily - it was designed to do so... any corrosion on the interference fit will lock it up even tighter.

Yeah, from what I've researched - the last thing you want to do is break the trans flange. I'd rather pay someone to take it off opposed to messing around and end up having to pull the transmission. Mine hasn't budged, Homer - hope you have better luck because I'm about to call "uncle" on mine.

TRBenj
04-16-2014, 05:39 PM
By definition, the shaft cannot be "seized up" if it has a proper interference fit. All worn (fretted) interference fit parts that I have encountered have been loose and sloppy.

If youre suggesting that the coupler and shaft were not pressed together, Im curious how you think they were assembled. The only other method that can be used to get them together is heat/cold. Yes, it SHOULD be difficult to get them apart- if they come apart easily then the parts are worn and need to be replaced. You might want to read up a little bit on how an interference fit works.

Wikipedia (http://en.wikipedia.org/wiki/Interference_fit)

Pressing the shaft off the coupler using the output flange of the transmission is standard industry practice. If that scares you, then cut the shaft and pony up for a new one.

supturb89
04-26-2014, 09:23 AM
Pressing the shaft off the coupler using the output flange of the transmission is standard industry practice. If that scares you, then cut the shaft and pony up for a new one.

I just removed mine using this method. Used four 2.5 inch 3/8ths bolts/nuts and a 3/4in socket to press against. I tightened the bolts very slowly in an opposing sequence. I would say that I didn't even tighten the nuts a full turn before the coupler popped forward a little. I still had to inch it off with the press the remaining distance. At no time during this did it seem like there was any undue stress on the transmission flange.

Now I just hope that I am able to get it back on after replacing the strut bearing.:confused:

chico
04-29-2014, 09:19 PM
that is a taper fit,load up the puller and get two dead blow hammers and hit the side of the coupler,it should pop right off.

TRBenj
04-30-2014, 12:23 PM
that is a taper fit,load up the puller and get two dead blow hammers and hit the side of the coupler,it should pop right off.
Dual taper prop shafts are out there, but are not standard on all boats. Single taper (on the prop end) is the standard for most direct drives, especially older ones. I believe we have established that the coupler to shaft mate is an interference fit on this particular boat. If there is no nut staring you in the face when you separate the couplers, that tells you its not a tapered shaft. You definitely do not want to "load up the puller and hit it with a hammer"... that only works for a tapered fit.

homer12
04-30-2014, 01:50 PM
TRBenj, not sure what you meant about the "nut staring you in the face". I did have to remove a nut in the middle of the coupling that threaded on to the shaft. It is also keyed, does the interference shaft have a key? I believe that this shaft was replaced by PO and therefore may be a taper fit. I've had some pressure and penetrating grease on it for a couple weeks now.

Time to get back to it soon when I can carve out substantial time to put it. I'll break out the heat again.

TRBenj
05-01-2014, 09:10 AM
I did have to remove a nut in the middle of the coupling that threaded on to the shaft. I believe that this shaft was replaced by PO and therefore may be a taper fit.
Well there you have it... you have a (non-original) dual taper shaft. That info (or a picture) would have been much more helpful at the beginning of the thread! A puller and a hammer should separate a tapered fit, unlike the original interference fit gear.

Yes, interference fit couplers are still keyed.

supturb89
05-02-2014, 10:36 AM
Well there you have it... you have a (non-original) dual taper shaft. That info (or a picture) would have been much more helpful at the beginning of the thread! A puller and a hammer should separate a tapered fit, unlike the original interference fit gear.

Yes, interference fit couplers are still keyed.

So I believe we all have the same shaft and coupler, because this is mine. Is this interference or taper? There is a nut on each end.

homer12
05-26-2014, 12:43 AM
Ok, had some success yesterday! Finally able to get the shaft coupling to break free! When it released it went "BANG" like I broke something and then was relieved to see this. I took 2 1/4" steel plates, drilled holes for the flange pattern and used all-thread/nuts to press this shaft off. That and this had been soaking with PB Blaster for weeks. Now time to finally replace the shaft log hose, packing material and get the shaft alignment done.

homer12
05-26-2014, 12:46 AM
BTW, does anyone know if there are any issues with using anti-sieze or something else when putting key, shaft and coupling back together?

homer12
05-26-2014, 11:21 PM
Got more work accomplished today. Time for a shaft alignment and then to the lake.... finally.http://img.tapatalk.com/d/14/05/27/3y5uze8y.jpghttp://img.tapatalk.com/d/14/05/27/4avy8equ.jpghttp://img.tapatalk.com/d/14/05/27/esegetes.jpg

Sent from my DROID RAZR using Tapatalk

mgs96ps
05-26-2014, 11:23 PM
I'm jealous...I had to pack mine around the shaft. Beautiful job!

FrankSchwab
05-26-2014, 11:50 PM
Looks excellent.

Make sure it drips good the first time out (a drip every 5-10 seconds), check it again about mid-year, and then once a year after that and it'll last you a long time.

homer12
05-27-2014, 10:20 AM
Thanks guys. Shouldn't have to do that again for a long time.