Changing prop shaft gland packing

[Trojan]

You can have to much packing in the cap. If I remember correct they were only designed for 2 wraps. If you notice when you have the cap off the male end of the shaft log has a ( V ) taper,tapering in. So when you tighten the cap,which is flat inside, it forces the packing into the (V)around the shaft sealing the shaft. If you have to much packing. You must use a lot more force to tighten the cap to get it to seal. Also it could just bunch up in the cap and may not seal proper. Which could cause the shaft log to run off center. This is the case where more is not better.You should almost be able to tighten the nut by hand. Just make sure you have the correct size packing. Make sure you cut the packing on a 45 Deg. and put the cuts 180 Degs.from each other. Just because you can get more packing in the cap does not make it correct. The added threades and space in the cap are required to withstand the compression force on the seal and keep the threads from stripping. Bill

 

[Nonchalant1]

You can have to much packing in the cap. If I remember correct they were only designed for 2 wraps. If you notice when you have the cap off the male end of the shaft log has a ( V ) taper,tapering in. So when you tighten the cap,which is flat inside, it forces the packing into the (V)around the shaft sealing the shaft. If you have to much packing. You must use a lot more force to tighten the cap to get it to seal. Also it could just bunch up in the cap and may not seal proper. Which could cause the shaft log to run off center. This is the case where more is not better.You should almost be able to tighten the nut by hand. Just make sure you have the correct size packing. Make sure you cut the packing on a 45 Deg. and put the cuts 180 Degs.from each other. Just because you can get more packing in the cap does not make it correct. The added threades and space in the cap are required to withstand the compression force on the seal and keep the threads from stripping. Bill

Trojan,

53MYs do not have a threaded cap. The cap is a collar with two threaded studs which have nuts to do the squeezing. GFO recommends 90 degree difference in cut placement. Your logic still applies though: more is not necessarily better. I'll use 3 rings like Genesis did.
Also, I think you're right that the whole packing is spinning, which is the cause of the wobbling gland when running.

Thanks,

Doug

 

[GaryNW]

a few comments/questions-
Back in the early 80's, one could buy the traditional flax/beeswax type packing or teflon impregnated. I thought the teflon sounded slick (yeah, pun intended) and specified it on a 4" shaft for a seiner. My thought was it should reduce temperature at a given squeeze force. Is the teflon still around? I had not heard of GFO- it must be slick as well...

On spinning the packing- This sounds odd to me. The shaft is smaller dia and probably smoother than the gland. Why on earth would the packing spin in the gland vs the shaft?

On wobble- If I had this, I think I would do shaft alignment at next haulout and strive to center the shaft in the log. I mean, alignment does not last forever, things settle and shift. My old sailboat auxilliary was out of line at some point in the boat's life and the shaft log was ovaled on the inside. The wall thickness was getting thin! Fix would have been a bitch as the log was a complicated casting that had the rudder hole integral.
Gary

 

[Trojan]

In a previous post he said the log wobbled and the shaft was in line.That would seam to be the only logical answer. More like bunching of the packing caused by a loose nut or old packing left in it. I agree it would be odd. But there are stranger things. Bill

 

[mike]

Found 4 packing rings in the shaft log. Also found the raw water intake seacock valves to be trashed. It's a real bear to remove the 2 1/2" seal nut, 5200 is tough stuff, it required a 4' pipe extension on a breaker bar to get enough leverage. I can report that the hull in the intake area is a full 1" thick.......and luckly found no delamination. mike

 

[Nonchalant1]

Mike,

Were you able to correct the alignment of the packing gland versus shaft and log? I don't know whether to try it on the rear (shaft log) side of the hose or the gland end of the hose. It seems like the shaft log side would adjust it better, but is that end pre-determined by the shaft log geometry instead of how the hose is attached? And do they put the shaft log hose on with some kind of sealer, making it almost impssible to move by just loosening the hose clamps?

Thanks,

Doug

 

[mike]

Doug,

I have not got that far along, still working on fixing the raw water intake. But at first glance it appears that both hose ends will have to be adjusted on my setup. When I removed all the packing the log sat down on the shaft. There is a tremendous amount of down pressure from the log hose. It is very apperent that the hose connection and alignment is critical. I don't believe a sealer is used between the hose, log and gland. But if one is concerened you could use Merc-cruser bellows glue, I have used it with great success on my old TRS drives in my offshore sport boat. The only problem is you have to be high and dry to use it. By the way, 3" long sheet rock scews driven into the packing makes for a good removal tool. Drive one in and pry it out with vise grips,...works great, just make sure you bias the screw away from the shaft and toward the log body. Mike

 

[Nonchalant1]

So thanks to this group, I repacked both of my prop shaft glands today (wet) with GFO. It took 3 hours because "nothing is ever simple". They're practically drip-free after 2 hours of running and a little adjusting. I'll watch them closely for another few running hours in May. Here's some "Lessons Learned":
1. The water coming in is not bad. Maybe a gallon in 2 minutes. The bilge pumps keep up with it easily (Rule 2000 pumps).
2. Mike absolutely saved my arse from a much longer ordeal digging out the old packing by recommending 3" long drywall screws as extractors. It's REALLY HARD to get the old flax stuff out and I had made a few sharp bent pick things to try, but with the drywall screws you just screw them into the flax and grab them with a vise grip and pull. THANKS MIKE !!!! I tried my pick things and a dental pick but that stuff is WAY stronger and wedged in way tighter than picks can get out. Only problem was I wanted 4" drywall screws to get at that last layer at the far end of the gland.
3. GFO works great. I knew to cut it at a 45 degree angle, but I didn't know which way the angle was supposed to be (overlapping front to rear or overlapping outside to inside. So I alternated them in the layers.
4. The fit of the 2 collars keeps any misaligned gland angle from misforming the GFO too much. Mine is too close on the top and too far on the bottom, but the collar minimizes that.
5. You use the collar to push in each successive layer of new GFO. The studs are long so the nuts tighten the layers in just fine.
6. I found 4 layers of flax and the wobbling port gland had a 5th partial layer that was a wad. I think it was incompletely removed from the previous time it was packed and was spinning like a wad at the bottom layer. I put 3 layers of GFO back in.
7. Both glands still have an almost imperceptible wobble when running, like maybe a 32nd or 64th inch. I'm going to let it go and watch it. The hoses were clamped stongly and had not moved on the shaft log any (thanks Jim). I'll watch that too. If Mike is successful in realigning glands by adjusting his shaft log hoses, I'll try that too whenever I have it hauled but it's $500 to haul at my marina that I don't want to spend.

Thanks again,

Doug Shuman

 

[Trojan]

They never run true true. That is why they use packing and a rubber boot instead of a seal or O ring with a solid mount. Glad you got it done. Another one under your belt. With stories like this. We will all start doing our own work. Sears have a regular packing remover kit. Bill

 

[Genesis]

West has a corkscrew pick on a flexible shaft with a T-handle on the end that works well.

Screw in and PULL.

Just don't get a defective one. I had one that wasn't swaged together properly and the pick part came out of the barrel when I yanked on it. That really pissed me off, because I then had to go get another one, and had a piece of pick in there which meant I had to get that other one RIGHT NOW and take care of it.

 

[jim rosenthal]

It's a bit late for this...but there is a solution that un-bonds polyurethane adhesives such as 5200. It is called Anti-Bond and boating stores have it, at least West does. It helps somewhat.

 

[mike]

Doug,

Why only 3 rings of GFO and not 4 ? I am getting ready to do the packing on this Wed. What made you decide to go with only 3?

I have been out a week now working on my Naiad stabilizers...what a pain in the arse. Had to remove and replace bearings and seals...so much for their "life-time seals" claim. The seals were fine, they just allowed water in to get at the bearings. Also had to replace both seacocks for my mains. By the way I found that some yard-bird put my water pick-up stariners on with inch long screws and penetrated the inside of the hull, causing local delamination. Had to dig it out, dry it and epoxy back fill. Mike

 

[Nonchalant1]

Mike,

Genesis put 3 rings on his, the GFO package said three, and there was just enough GFO in one package to do three.

I didn't try to adjust my log hose (too scary in the water!) so I'm interested in yours. There was a lot of downward pressure on the gland, pushing it closer at the top as we discussed. I found that by placing the GFO on a very smooth flat surface and pounding it a little flatter with a hammer, that I could get it squeezed in easier at the top where it's tight. You carefully remember which side was on the flat surface (I used the GFO label side as a marker) and put that side of the GFO against the shaft so there are no "dents" from the hammer on the shaft sealing surface.

If I were out of the water, I'd loosen just the aft hose clamps and try to spin my whole gland and hose 180 degrees so any hose droop is now upward pressure. If the hose is straight, then the problem is in the shaft log design, as you indicated. ("Shaft Log" is that fiberglass, log shaped, hose holder that the shaft goes through as a through-hull in the boat. On a bare hull, it looks like a log.)

Tell me how it goes.

Doug Shuman

 

[mike]

Doug, thanks for the info. I can get a finger in the bottom gap on the log, the top sits right on the shaft. I'll try to give it a go with your idea of reversing the packing gland 180 deg., assuming I can get the log hose loose with out tearing it up. I want to avoid removing the coupling from the shaft...that is a real pain. I'll keep you all posted on my success or failure... thanks, mike

 

[Nonchalant1]

Mike,

If you can't spin it 180 - I used a 2" dia. 3 ft. long pipe placed on the hull and against the bottom of the gland as a lever to lift it up to get the GFO in. I would think that a car scissor jack with one or two bricks as a base might hold it in any position more easily, or even lift it after you undo the clamps. You'd have to be careful not to apply too much force with the scissor jack.

Doug

 

[solanderi]

Am reading w/ interest this thread as after my last run I have developed a 2 drip per second leak on the port shaft log. BTW I noted that the shaft did not use to turn while in neutral, then began to slowly turn and after the last run began to leak. The logs were previously almost completely dry. I have enclosed a picture of the culprit (the actual shaft log does not have any letters on it, ha ha) but I would just like to confirm that it is letters A - D that I am cranking down on to stem the flow.

Also, what kind of operating temps should I expect and where exactly should I read off? Shaft, log etc...

Thank you for the FIX YOUR HATT BY THE NUMBERS lesson.

 

[solanderi]

Here is the picture. Thanks

 

[Genesis]

Nope - it is "E" and "F" you turn to cinch down the packing.

The others are the log hose clamps - if they're tight leave 'em alone. Cranking them won't stop the leaking if its the packing.

(PS: Nice spray deflector on the shaft! I like it!)

PPS: Next time you CHANGE the packing run a nut down each of those long studs BEFORE you put the collar on. That way you can use them to jack off the collar the next time you need to get in there to change it. Its a royal bitch to get it out otherwise....

 

[Nonchalant1]

Karl,

OK.

Doug

 

[Genesis]

Now now, let's keep it clean around here....