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Ndawg12

Thru-hull Drain Plug Leaking

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Ndawg12

My midship thru-hull plug is leaking, not alot, a very slow trickle, but enough to annoy me.  The T-handle plug will not even come close to threading in enough to seat and utilize the o-ring.  I don't think it ever did thread in all the way but I know it hasn't always leaked.  I suspect that the different pressures of my lift bunks (new this this past season) have slightly warped it some how.  Anyways, I haven't tried thread tape on the plug threads but I doubt it will work, can I run a 3/4 tap through it?  I think it's tapered, is the plug tapered, the port, or both?  Any other ideas?

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minnmarker

Been through the same issue.  Clean the threads (male and female) with a wire brush and then put some anti seize on the threads.

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Kmfish87

You could run a tap through it but make sure that the tap is a 3/4 npt tap and that you dont go too far as the tap and threads are tapered. If you go to far in you will never get the plug to seal.
 I would try the wire brush method first. Im sure you could find a small, round brush in the plumbing section of a hardware store that would work well for getting into the threads of the hull bung [read in Bevis and Butthead voice]

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formulaben

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Ndawg12
3 hours ago, minnmarker said:

Been through the same issue.  Clean the threads (male and female) with a wire brush and then put some anti seize on the threads.

all threads are clean, nothing is gulled or burred, not sure how the anti-seize helps to stop the leak?  It feels like the female port is ever so slightly out-of-round.  

 

1 hour ago, Kmfish87 said:

You could run a tap through it but make sure that the tap is a 3/4 npt tap and that you dont go too far as the tap and threads are tapered. If you go to far in you will never get the plug to seal.
 I would try the wire brush method first. Im sure you could find a small, round brush in the plumbing section of a hardware store that would work well for getting into the threads of the hull bung [read in Bevis and Butthead voice]

Yeah, remember these T-handle plugs have an o-ring.  Double protection.  On the other one by the engine I can thread the plug in ~ 3/4 of the way and it won't leak, torque it down to compress the o-ring on the lip, double protection.  I'm thinking if I could atleast get it to thread all the way down then the o-ring would stop the leak.

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Choiceind

Use pipe dope, its a paste with teflon tape pieces in it.

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John I.

Drain plug on a buddy's boat leaks ever so slightly, although it is not the o-ring type. Teflon tape or marine grease seems to cure it.  

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coldwater-echelon

Not totally sure but I think the plugs with the oring are straight threads, not npt. Might want to check with bakes or another dealer. 

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electricjohn

I agree with coldwater.

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minnmarker
19 hours ago, coldwater-echelon said:

Not totally sure but I think the plugs with the oring are straight threads, not npt. Might want to check with bakes or another dealer. 

:plus1:  Cleaning and lubing the threads should help.  I use silicone grease on the O rings - and on the ballast quick connects - and on most every other piece of rubber that seals against water leakage.

https://www.amazon.com/Super-Lube-92003-Lubricating-Translucent/dp/B0081JE0OO

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mikeo

I don't see a picture, but if it's anything like what's on the bottom of my boat it's easily replaceable with a new thru-hull and t-handle. I had to rotate one of my thru-hulls 90* so I could use it for a ballast system input and still get the 1/4 turn valve on the top to work; I unscrewed the 4 scres going in to the hull while the boat was on the trailer and pushed the assembly out from the top with the t-handle.

You can get a new thru-hull and t-handle from a marine supply shop, and then use 3M 5200 in white or black (depending on your hull color) to seal the thru-hull to the boat again. I would suggest keeping the boat on the trailer for at least a week to get the 5200 to fully cure.

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