Sealing pipe plug

[Mdparrott]

Does a pipe plug (such as on the bottom of Sherman transmission) require any sealant when reassembled, or am I correct in thinking none is required on a tapered NPT plug? Thanks..

 

[Dell (WA)]

do you mean gookem-chuck or puckey? NO that is why you have gaskets. Howsomever, the square headed diffy drain plug (353064) is tapered 1/2" pipe thread ........HTH, the amazed Dell

 

[Royse]

I can't speak directly to that plug on the Sherman.
Pipe thread sealer is made because it is serves a purpose.
I'm not a fan of the Teflon tape type.
I prefer the paste type made for use with gas and oil.
It does require that you let it dry before use though.

 

[Hobo,NC]

Pipe threads are spose to be self sealing that has held true till the Chinese got involved. I use pipe dope/past for two reasons.

1) true are not to guard again corrosion and the threads rusting so bad it will not come apart.

2) For the self seal effect to happen it needs lucubration so you can tighten it up enough to get a seal.

Its possible to crack the case so don't get mean with it :!: Dope it up with sum'N.

 

[Mdparrott]

(quoted from post at 18:20:31 10/15/16) I can't speak directly to that plug on the Sherman.
Pipe thread sealer is made because it is serves a purpose.
I'm not a fan of the Teflon tape type.
I prefer the paste type made for use with gas and oil.
It does require that you let it dry before use though.


Yeah, somewhere I thought a tapered pipe plug didn't have to have any "acme-sticky" applied. Had about 10 drips in a week coming out the cotter pin on the bottom, re-split the tractor and got about 1/2 a turn more on the plug (boy THAT was fun).

Still have just a little weep in the threads, but no drips yet. Going to try to put just a little more tweek on it and see if it'll completely seal. A little concerned about over-tightening and cracking something.

 

[Royse]

(quoted from post at 21:37:11 10/15/16)

(quoted from post at 18:20:31 10/15/16) I can't speak directly to that plug on the Sherman.
Pipe thread sealer is made because it is serves a purpose.
I'm not a fan of the Teflon tape type.
I prefer the paste type made for use with gas and oil.
It does require that you let it dry before use though.


Yeah, somewhere I thought a tapered pipe plug didn't have to have any "acme-sticky" applied. Had about 10 drips in a week coming out the cotter pin on the bottom, re-split the tractor and got about 1/2 a turn more on the plug (boy THAT was fun).

Still have just a little weep in the threads, but no drips yet. Going to try to put just a little more tweek on it and see if it'll completely seal. A little concerned about over-tightening and cracking something.

You sure don't want to crack the casing.
Beg, borrow or buy a pipe thread tap and chase the threads.
They are not likely to seal if dirty and getting an extra half turn
makes me think that maybe they are. Cleaning them should take
almost zero force, you're not cutting new threads, only cleaning.

I use sealer on the threads only, don't let it get on the end of
the plug. Install and snug up good, then let it dry before use.

 

[Gerald L]

Pipe threads properly cut will screw in by hand two turns and four with a wrench deforming the treads to mate up mettle to mettle teaflon
is not a pipe thread sealant it is actually a lubricant and prevents galling of the threads this was accomplished the first time it was
installed in the hole just need to have a little oil on the threads to prevent damage to the mettle to mettle seal providing the plug has not
been abused by over tightened if you think it is damaged a new american made pipe plug from a shop that does gas and propane plumbing, is
your best bet. Count the threads on the plug there should be 8 total remember 2 threads by hand 4 in and 2 showing. You should be able to
screw the plug in with a standard length open end wrench if not the threads in the hole or the plug were probably not cut properly or they
were not clean or possibly rusty

 

[Mdparrott]

Ive got about 3 threads still showing. Does that mean I ought to have at least another thread I can tighten w/o fear of cracking it?

I've used an 11 MM combination wrench to tighten it with a 1 inch wrench over the end to extend it because its too tight to get my big hands in there with the transmission installed. And that's my worry, the extra leverage I e got. So far it still moves pretty easy.

 

[Gerald L]

The 2-4-2 is an ideal situation: properly cut threads etc. I would not get caried away with to much torque the plug is tapered and will act
like a wedge on the case. I would get some hands on help if I was not sure,you do not want to break the case. I do not know what the number
of FT LBS but I am going to look it up

 

[Gerald L]

I found a chart it said 54 ft lbs on 1/2 pipe , you should look it up on the net just to make sure I do make mistakes. hope this helps

 

[Royse]

"I ought to have at least another thread I can tighten w/o fear of cracking it?"

You're the only one who can judge how much torque you have on it.
You can clean it and seal it 10 times if you wanted to.
It only takes one little over-step to crack it.
Your choice of course, but I would use caution.

If it still won't seal you might consider a solid brass plug.
Solid because they're stronger than the hollow versions.
Brass threads seem to be more forgiving to imperfections
than a steel/iron plug in my experience.

Noted - brass is not recommended in all scenarios.

 

[Tall T]

(quoted from post at 16:39:08 10/15/16) Does a pipe plug (such as on the bottom of Sherman transmission) require any sealant when reassembled, or am I correct in thinking none is required on a tapered NPT plug? Thanks..

It would take some extreme torque to bust a housing with a filler or drain plug and the casings are built up there as well. Keep your wrench length short and when in doubt . . . back off and re-snug the plug a couple of times untill you get the feel of absolute tightness with a hair for good measure.

I use whatever is in a casing to lubricate its plug. The taper does the sealing. Wipe the area clean afterward for checking and if it weeps, tighten it a little more. Doesn't take much to cork a tapered hole.

 

[Hobo,NC]

Clean the case and look it may already be cracked...

 

[markct]

No he means the tapered pipe plug such
as the bottom of a Sherman
transmission...no gasket involved

 

[kylemorley]

Never underestimate the power of a wedge, which is what a NPT fitting is, to break things. I've got a woodsplitter that works just like a tapered plug fitting, and can pop
apart a 3' oak round..

I like Locite Anerobic Teflon sealant, for knackered assemblies and threads that refuse to seal normally. Sort of a combination of Loctite and thread paste, it will seal where nothing else will and laughs at high pressure. Not cheap though.

 

[Mdparrott]

Thanks for all the great feedback, fellas. I'd like to get it to seal without having to pull the Sherman back out but I guess that wouldn't be the end of the world.

I'm going to try REAL gentle to see if I can't put another little tweek on it first. Appreciate all of the advice.

 

[howdy1960]

I can only share that my FEL drain plug kept sucking air till I pipe doped it.