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Old 17-05-2017, 09:01   #1
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Packing nut keeps backing off ...

I've replaced the packing with Gore-Tex and when I adjust everything, it all seems good: no leaking at rest; a tiny amount while under power. But, especially during close quarters manevering (specifically backing), the nut loosens up and the drip becomes a bit more like a stream. I can go back, turn it a few turns and everything is back to normal.

I have tried using locktite in the threads, but that hasn't solved the problem.

Any suggestions from the Brain Trust?
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Old 17-05-2017, 09:04   #2
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Re: Packing nut keeps backing off ...

You don't mention tightening the lock nut. An omission or is there none?
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Old 17-05-2017, 09:07   #3
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Re: Packing nut keeps backing off ...

Quote:
Originally Posted by S/V Illusion View Post
You don't mention tightening the lock nut. An omission or is there none?
Yes, the lock nut is tightened. It's backing off on the thread into the box.
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Old 17-05-2017, 10:09   #4
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Re: Packing nut keeps backing off ...

Lock nut - Is a second nut on the same thread that is tightened onto the adjusted nut.

Do you have a second nut on it?
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Old 17-05-2017, 10:37   #5
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Re: Packing nut keeps backing off ...

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Originally Posted by paulajayne View Post
Lock nut - Is a second nut on the same thread that is tightened onto the adjusted nut.

Do you have a second nut on it?
Yes, and as I said, it is tight. This isn't where the problem is. The problem is that the entire stud, including both nuts, back out of the box at low RPM (and/or in reverse). I might add that the shaft has recently been aligned, a month ago, and there is no vibration there.
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Old 17-05-2017, 10:42   #6
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Re: Packing nut keeps backing off ...

Back off the nuts and then lock them together -


Using the locked together nuts tighten the stud and then re-adjust the lock nuts to tighten the gland.

HTH
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Old 17-05-2017, 12:08   #7
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Re: Packing nut keeps backing off ...

How is the "stud" being held in the stern tube?
Normally, they are held in a rubber hose sleeve with hose clamps.
Is that what you have? A pic would help.
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Old 17-05-2017, 14:32   #8
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Re: Packing nut keeps backing off ...

I'm guessing, this type?

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Any way to get nuts on the back side, like in that pic? Nylocs?

PS... That's not mine, I would never paint like that.
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Old 17-05-2017, 14:53   #9
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Re: Packing nut keeps backing off ...

Quote:
Originally Posted by Fiveslide View Post
I'm guessing, this type?

Attachment 147961

Any way to get nuts on the back side, like in that pic? Nylocs?

PS... That's not mine, I would never paint like that.
Can't get to the other side. The bolts go into the casing on the back side.
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Old 17-05-2017, 15:00   #10
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Re: Packing nut keeps backing off ...

Quote:
Originally Posted by sneuman View Post
Can't get to the other side. The bolts go into the casing on the back side.
Is there enough room for a locknut between where the stud goes in and the adjustable plate?
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Old 17-05-2017, 15:04   #11
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Re: Packing nut keeps backing off ...

What follows is written in a friendly tone of voice, and with the sole intent to help you and others who may read this thread for knowledge about this subject "Packing Nut Loosens Itself" or "Packing Gland Leaks" or "How to Service a Packing Gland."

My Friendly Suggestion: For a problem like this, I think photos with captions identifying the CURRENT specific installation on your boat are helpful to others who may be able to see things done incorrectly or missing or questionable.

So, post a photo showing the installation as it NOW exists, and add some captions to it identifying where the problem seems to be ("Leaks from here...").
__________

Here are a few photos that have captions to identify parts. These photos are NOT from the following article, but are posted here for reference by others.

And Here is a link to an excellent online article by a CF member (MAINESAIL) or Compass Marine who has seen a lot of problems and has described the standard installation and has photos in his article to illustrate the steps to cleaning, repacking, and properly tightening the nuts and the parts used and tips. Highly Recommended.

Re-Packing A Traditional Stuffing Box Photo Gallery by Compass Marine How To at pbase.com

Hope that helps you or others in the future.
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Old 17-05-2017, 16:01   #12
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Re: Packing nut keeps backing off ...

Great post Steady!
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Old 17-05-2017, 16:42   #13
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Re: Packing nut keeps backing off ...

If the entire assembly is backing out it could indicate the hose clamps are improperly tightened or improperly installed and/ or the packing or compression nut was overly tightened causing the packing material to get hot and grab at the shaft. This could cause the entire assembly to turn slightly and begin to back out when you go into reverse. Try putting an index mark on the assembly and on the hose and see if the assembly has turned when you run the engine under load.
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Old 17-05-2017, 17:56   #14
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Re: Packing nut keeps backing off ...

Don't even have a prop shaft...(saildrive)
How about a tab washer between nut and locking nut?
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Old 18-05-2017, 08:11   #15
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Re: Packing nut keeps backing off ...

Quote:
Originally Posted by Steady Hand View Post
What follows is written in a friendly tone of voice, and with the sole intent to help you and others who may read this thread for knowledge about this subject "Packing Nut Loosens Itself" or "Packing Gland Leaks" or "How to Service a Packing Gland."

My Friendly Suggestion: For a problem like this, I think photos with captions identifying the CURRENT specific installation on your boat are helpful to others who may be able to see things done incorrectly or missing or questionable.

So, post a photo showing the installation as it NOW exists, and add some captions to it identifying where the problem seems to be ("Leaks from here...").
__________

Here are a few photos that have captions to identify parts. These photos are NOT from the following article, but are posted here for reference by others.

And Here is a link to an excellent online article by a CF member (MAINESAIL) or Compass Marine who has seen a lot of problems and has described the standard installation and has photos in his article to illustrate the steps to cleaning, repacking, and properly tightening the nuts and the parts used and tips. Highly Recommended.

Re-Packing A Traditional Stuffing Box Photo Gallery by Compass Marine How To at pbase.com

Hope that helps you or others in the future.
By the way, I believe the picture showing the packing being wound onto the shaft is actually an improper way of installing the packing. At least not the way I was taught. I believe you make individual rings with the packing and alternate the cuts 180 degrees. That way the water cannot channel its way through the packing.
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