Do our coaches have a gas tank drain plug?

M

mike

New member
Dec 31, 2000
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I filled up prior to heading home after I picked-up my coach, drove approximately two and a half hours and parked in my shop. It's been there for 3
weeks.

Today I noticed a couple of additional water drains in the floor, kitchen area, directly across from doorway. I'm not certain if the kitchen was
always located in this area (75 Royale), so I opened the taps and placed a small bucket under the coach to catch whatever was there, not much,
however, while there I noticed a smell of gas. Small stain on the floor.

Got a light and had a look, it appears to be a very small leak, maybe a few drips per hour? It looks like there is a drain plug directly above where
this leak is coming from but I'm not certain, I'll have a better look tomorrow.

Did our coaches have drain plugs in the gas tank/s?

If not is there a quick fix until I can get this?

Thanks,
Mike
 
Yes, there is a drain plug in each tank. It has a hex opening which will take an Allen wrench or a socket with a hex shaft. They sometimes rust and strip out. If so I have once used a small pipe wrench on a couple of exposed threads to turn a plug out.

Emery Stora
77 Kingsley
Frederick, CO

>
> I filled up prior to heading home after I picked-up my coach, drove approximately two and a half hours and parked in my shop. It's been there for 3
> weeks.
>
> Today I noticed a couple of additional water drains in the floor, kitchen area, directly across from doorway. I'm not certain if the kitchen was
> always located in this area (75 Royale), so I opened the taps and placed a small bucket under the coach to catch whatever was there, not much,
> however, while there I noticed a smell of gas. Small stain on the floor.
>
> Got a light and had a look, it appears to be a very small leak, maybe a few drips per hour? It looks like there is a drain plug directly above where
> this leak is coming from but I'm not certain, I'll have a better look tomorrow.
>
> Did our coaches have drain plugs in the gas tank/s?
>
> If not is there a quick fix until I can get this?
>
> Thanks,
> Mike
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
To jump onto the thread here, it seems that my PO went the one big tank route. Using the drain plugs to combine tanks. I haven't had too close a look
yet, but any thoughts/ideas on a repair here? It looks like he added 45 degree nopples to the drain openings. Am I screwed? Can this be reverted?
Assuming the drains are not stripped.
--
1976 Palm Beach
Austin, TX
 
> To jump onto the thread here, it seems that my PO went the one big tank route. Using the drain plugs to combine tanks. I haven't had too close a
> look yet, but any thoughts/ideas on a repair here? It looks like he added 45 degree nopples to the drain openings. Am I screwed? Can this be
> reverted? Assuming the drains are not stripped.

Adam,
The drains are a 1/4 pipe thread (IIRC) and flush plugs can be had.
Matt
--
Matt & Mary Colie - Members GMCMI, GMCGL, GMCES
'73 Glacier 23 - Still Loving OE Rear Drum Brake with Applied Control Arms
Now with both true Keyless and remote entry
SE Michigan - Twixt A2 and Detroit
 
thanks Matt. Any idea how long the plug needs to be minimum? I'm assuming a standard 1/4 inch plug will do.
--
1976 Palm Beach
Austin, TX
 
Adam, yes the 1/4NTP short plug with Allen will work.

On Sun, Nov 20, 2016 at 10:40 AM, Adam Metzger
wrote:

> thanks Matt. Any idea how long the plug needs to be minimum? I'm
> assuming a standard 1/4 inch plug will do.
> --
> 1976 Palm Beach
> Austin, TX
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk
http://www.appliedgmc.com
1-800-752-7502
 
Put a wrap of teflon tape on the plug and set it tight.
As to connecting the drains together, it strikes me as a Bad Idea. If the selector is still there, on a hill you can set it such that you pull air
even when there's gas, depending the setting and whether you're going uphill or downhill. With the selector removed, one way or the other has the
potential to leave you pulling air before your time. In addition to which there's not a lot of clearance under there. The frame rails protect the
tanks, but a well placed rock or curb will remove the coupling if it's below the frame level - which it surely must be.

--johnny
--
'76 23' transmode Norris upfit, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.

"Sometimes I wonder what tomorrow's gonna bring when I think about my dirty life and times" --Warren Zevon
 
> Put a wrap of teflon tape on the plug and set it tight. ...
I was wondering what kind of sealant to use. I would have figured gas would dissolve Teflon tape, though. I guess an immersion test is in order.
--
73 23' Sequoia 4 Sale
73 23' CanyonLands Parts Unit 4 Sale
Upper Alabama
"Highest price does not guarantee highest quality."
 
Lemme know if it does dissolve. Cos if it does, I have committed three or four dreadful sins which I'll need to atone. Ricky the (large) Onan Guru
always sealed the fuel lines with paint on Teflon sealer, Diesel doesn't seem to bother it.

--johnny
--
'76 23' transmode Norris upfit, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.

"Sometimes I wonder what tomorrow's gonna bring when I think about my dirty life and times" --Warren Zevon
 
> Lemme know if it does dissolve. Cos if it does, I have committed three or four dreadful sins which I'll need to atone. Ricky the (large) Onan
> Guru always sealed the fuel lines with paint on Teflon sealer, Diesel doesn't seem to bother it.
> --johnny
Teflon might work fine. I just never assume that something that works for water will work for gas. I remember as a kid I needed about a half cup of
gas for something. I poured some out of a jerry can into a Styrofoam cup that dissolved instantly.
--
73 23' Sequoia 4 Sale
73 23' CanyonLands Parts Unit 4 Sale
Upper Alabama
"Highest price does not guarantee highest quality."
 
> Ah but wait. I remember one of our mechanics having to replace a bleeder on one of our pumps (oil and gas barge) and he had used some teflon tape
> that was yellow. I asked him what the difference in the two (white/yellow) and his explanation was that it could be used with the different
> chemicals that our pumps are accustom to (ie: gas,av gas,naptha, benzene,fuel oil etc.). Now, I have no idea on were to get it but I did get some
> from him and used it on my gas tank plugs with no issues. JWID
They sell the yellow stuff at hardware stores for propane plumbing. Dunno if it works for gasoline. Will have to read the label sometime.
--
73 23' Sequoia 4 Sale
73 23' CanyonLands Parts Unit 4 Sale
Upper Alabama
"Highest price does not guarantee highest quality."
 
Googled "Does gasoline dissolve Teflon tape" and this popped up:

http://www.jamestowndistributors.com/userportal/document.do?docId=563

Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808

-----Original Message-----
From: A.

I was wondering what kind of sealant to use. I would have figured gas would dissolve Teflon tape, though. I guess an immersion test
is in order.
--
 
> Googled "Does gasoline dissolve Teflon tape" and this popped up:
> http://www.jamestowndistributors.com/userportal/document.do?docId=563
>
> Regards,
> Rob M.
> The Pedantic Mechanic
> USAussie - Downunder
> AUS '75 Avion - The Blue Streak TZE365V100428
> USA '75 Avion - Double Trouble TZE365V100426
> USA '77 Kingsley - TZE 267V100808
It looks like I need to ask Santa for a can of Permatex aviation form-a-gasket no. 3. If power steering fluid/ATF won't dissolve it, I can use it for
everything mechanical that I do.
--
73 23' Sequoia 4 Sale
73 23' CanyonLands Parts Unit 4 Sale
Upper Alabama
"Highest price does not guarantee highest quality."
 
I have a friend who put his airplane down in an outside storage yard when the engine quit about 2 miles short of the runway in Gary, IN. The next day
when we went to find out what was wrong and refrieve it, we found a piece of teflon tape in the carb. We removed he teflon piece and used this FAA
approved stuff to reseal seal it.

https://www.permatex.com/products/gasketing/gasket-sealants/permatex-aviation-form-a-gasket-no-3-sealant-liquid/

BTW, he claimed that he never used teflon tape on that airplane. It may have been there for many years. It got in there somehow. I often wondered
if he might have gotten it at some refueling place with a load of gasoline.

--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
Well, I've learnt something else. Fortunately when I tape a joint, I keep the tape to about half the threads, and never lap it over the bottom of the
fitting for the reasons noted. I'm gonna go to the Permatex product though and save the teflon tape for home plumbing.

--johnny
--
'76 23' transmode Norris upfit, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.

"Sometimes I wonder what tomorrow's gonna bring when I think about my dirty life and times" --Warren Zevon
 
My best guess would be that I have disagreed with Ken Burton twice in the last decade, and I can't remember (and don't choose to) the first time.

In this application I would not use any of the older Permatex family. Ken can use it in aircraft because avefuel does not contain any alcohol of any
type. Permatex 1, 2 & 3 all have some solubility in alcohol. It is different with different alcohols but ethyl* and methyl* are very real. This
killed a lot of 2-stoke engines with the introduction of alcohol in motor fuels, but I won't go into that in great detail here and now.

I would use teflon tape or a teflon loaded pipe thread sealant.

If I were to use a thread sealant, I would (as demonstrated in a study by the ASTM Sealing System Group) apply it to the female thread and the male
thread both. It was suggested that applying it to the male thread is solely for the purpose of allowing an inspector to confirm that a sealant was
applied. When applied to the male thread it is only a slight improvement over a light lubricating oil. The sealant will be scraped off as the
fittings are assembled. But, if the first two threads of the female are loaded (not even a 100% fill) the sealant will be carried into the joint
during assembly and can even in some cases form an interior bead. This also means that the appropriate thread sealant be used for the service and
that is why this is less popular with trade plumbers.

I would (I believe I did many of the times I have had my tanks down - other long stories) use teflon tape - plain white - The tape was the width of
the threads on the plug and I would use about 1 & 1/2 turns wrapped in the thread direction. This will prevent water or alcohol intrusion from both
the top (inside the tank) and the bottom (road salt). In this fashion, there is a better than even chance that when you (or some SO) want to drain
the tanks again, that plug might be useful. There will be no loose teflon to foul things.

Unlike the KenB's airplane story, our fuel systems are different. We have a "sock" on the fuel pick up and there is a fine filter at the carburetor
inlet (if it exists) and many have an added filter along the way. If you have fuel injection of almost any type, debris filters should have been
included.

I kind of hate to include any more negative comments about Permatex, I use it to advantage and have seldom had problems that I did not cause, but
there is one that I remember well. Another story not for here/now, but "non-hardening" does not mean never hardening. If it is a screw thread that
you might ever have to disassemble, you may find that after a few years it has become what I would call hard, quite hard.

Matt
--
Matt & Mary Colie - Members GMCMI, GMCGL, GMCES
'73 Glacier 23 - Still Loving OE Rear Drum Brake with Applied Control Arms
Now with both true Keyless and remote entry
SE Michigan - Twixt A2 and Detroit
 
> ...In this application I would not use any of the older Permatex family. ... Permatex 1, 2 & 3 all have some solubility in alcohol. It is
> different with different alcohols but ethyl* and methyl* are very real. This killed a lot of 2-stoke engines with the introduction of alcohol in
> motor fuels, but I won't go into that in great detail here and now.
>
> I would use teflon tape or a teflon loaded pipe thread sealant. ...
I know the old formulations of Permatex would dissolve in alcohol. I guess the aviaton stuff probably still will.

If Matt Colie says the white Teflon tape is ok, it is ok. So that's what I will use from now on.
--
73 23' Sequoia 4 Sale
73 23' CanyonLands Parts Unit 4 Sale
Upper Alabama
"Highest price does not guarantee highest quality."
 
G'day,

Matt's message got me to thinking a bit and here's some comments:

1) I have used Teflon tape on pipe fittings FOREVER and never had any problems with pieces winding up where they should not be.
HOWEVER, when wrapping the fitting it is important to use the correct width tape be it 1/8 inch wide or 3.8 inch wide. Start the
tape 2 threads up from the end of the fitting and use a MAX of 2 wraps pulling the wraps tight as you wrap.

2) I have used Teflon tape on pipe threaded fuel fittings, if I remember correctly when gasoline came in contact with the tape it
turned from white to translucent. I didn't think it mattered because when the taped male fittings were screwed into the female
fittings they did not leak.

3) I'd bet dollars to donuts that pipe fittings when screwed together have places that are a metal to metal fit with no tape in
between them.

4) I have purchased fittings from McMaster Carr that came with what I believed to be Teflon sealant on the pipe threads.

Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808

-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of Matt Colie
Sent: Tuesday, November 22, 2016 3:02 AM
To: gmclist
Subject: Re: [GMCnet] Do our coaches have a gas tank drain plug?

My best guess would be that I have disagreed with Ken Burton twice in the last decade, and I can't remember (and don't choose to)
the first time.

In this application I would not use any of the older Permatex family. Ken can use it in aircraft because avefuel does not contain
any alcohol of any type. Permatex 1, 2 & 3 all have some solubility in alcohol. It is different with different alcohols but ethyl*
and methyl* are very real. This killed a lot of 2-stoke engines with the introduction of alcohol in motor fuels, but I won't go
into that in great detail here and now.

I would use teflon tape or a teflon loaded pipe thread sealant.

If I were to use a thread sealant, I would (as demonstrated in a study by the ASTM Sealing System Group) apply it to the female
thread and the male thread both. It was suggested that applying it to the male thread is solely for the purpose of allowing an
inspector to confirm that a sealant was applied. When applied to the male thread it is only a slight improvement over a light
lubricating oil. The sealant will be scraped off as the fittings are assembled. But, if the first two threads of the female are
loaded (not even a 100% fill) the sealant will be carried into the joint during assembly and can even in some cases form an interior
bead. This also means that the appropriate thread sealant be used for the service and that is why this is less popular with trade
plumbers.

I would (I believe I did many of the times I have had my tanks down - other long stories) use teflon tape - plain white - The tape
was the width of the threads on the plug and I would use about 1 & 1/2 turns wrapped in the thread direction. This will prevent
water or alcohol intrusion from both the top (inside the tank) and the bottom (road salt). In this fashion, there is a better than
even chance that when you (or some SO) want to drain the tanks again, that plug might be useful. There will be no loose teflon to
foul things.

Unlike the KenB's airplane story, our fuel systems are different. We have a "sock" on the fuel pick up and there is a fine filter
at the carburetor inlet (if it exists) and many have an added filter along the way. If you have fuel injection of almost any type,
debris filters should have been included.

I kind of hate to include any more negative comments about Permatex, I use it to advantage and have seldom had problems that I did
not cause, but there is one that I remember well. Another story not for here/now, but "non-hardening" does not mean never
hardening. If it is a screw thread that you might ever have to disassemble, you may find that after a few years it has become what
I would call hard, quite hard.

Matt
 
I wonder why combining the two tanks as the PO in this example had done would be a bad idea?

Curious minds want to know!

Thanks,
Dave
--
David del Rio - 75 Avion - Raymond, CA
 
#3 Permatex is what Manny uses on the transmission chain covers. Left a
big jar on the shelf here. For some reason, I hadn't used it in a long
time. Last month a friend came back here with a badly leaking final
drive-to-transmission gasket which we'd installed with a new engine and
transmission early in the summer. When we examined the gasket, it looked
perfect with clear, complete impressions on both sides. So we put the
Permatex on both sides. He hasn't had a drop of leakage during a couple of
trips since.

One thing: He had the 3:21 FD filled to the plug. I told him to only fill
it to 3/4" lower (Is that the correct level?). Is it likely that the
over-fill caused the leakage -- even when static (big puddle on the hanger
floor after a week)?

Ken H.

> I have a friend who put his airplane down in an outside storage yard when
> the engine quit about 2 miles short of the runway in Gary, IN. The next day
> when we went to find out what was wrong and refrieve it, we found a piece
> of teflon tape in the carb. We removed he teflon piece and used this FAA
> approved stuff to reseal seal it.
>
> https://www.permatex.com/products/gasketing/gasket-
> sealants/permatex-aviation-form-a-gasket-no-3-sealant-liquid/
>
>
> BTW, he claimed that he never used teflon tape on that airplane. It may
> have been there for many years. It got in there somehow. I often wondered
> if he might have gotten it at some refueling place with a load of gasoline.
>
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
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