Do our coaches have a gas tank drain plug?

[Jim Hupy]

What I do with final drives, is to fill it to the point where your little
finger when bent at the first knuckle, just touches the fluid. A bit less
than 2 quarts.
Jim Hupy

> #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
> >
> > _______________________________________________
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> >
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[johnny]

Dave, see my post on the matter above. If you're down to 1/4th tank or so and the tanks are connected, the downhill tank will fill, emptying the
uphill tank. If you have the uphill tank selected, you'll pull air even though there's fuel. This is why the fill tube is above the bottom of the
tanks... they're connected till about a quarter tank, then they're separate. Worse, the connection is going to hang below the frame. catch a bump or
FOD just right and you'll clean the connection off the tanks and probably damage them in the bargain.
Given the constraint they had to work with - a very shallow space in which to store 50 gallons of gas - the designers did a very good job.

--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

 

[Jim Hupy]

For those folks out there who consistently run on fumes, you will
experience fuel starvation on a regular basis. If you have to walk 5 miles
in rain with a 5 gallon jerry can, it might serve as a lesson in GMC fuel
tank arrangements. Keep em above half full at all times and you won't have
to worry about any of this.
Jim Hupy
Salem, Or
78 GMC ROYALE 403.

On Nov 21, 2016 4:53 PM, "Johnny Bridges via Gmclist" <

> Dave, see my post on the matter above. If you're down to 1/4th tank or so
> and the tanks are connected, the downhill tank will fill, emptying the
> uphill tank. If you have the uphill tank selected, you'll pull air even
> though there's fuel. This is why the fill tube is above the bottom of the
> tanks... they're connected till about a quarter tank, then they're
> separate. Worse, the connection is going to hang below the frame. catch a
> bump or
> FOD just right and you'll clean the connection off the tanks and probably
> damage them in the bargain.
> Given the constraint they had to work with - a very shallow space in which
> to store 50 gallons of gas - the designers did a very good job.
>
> --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
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[robert smith]

Yes but good luck getting the plugs loose without a torch. Not difficult but you will probably have to re-solder the bung.

 

[david horowitz]

thanks a bunch Johnny... i get it now!
--
David del Rio - 75 Avion - Raymond, CA

 

[hal stclair]

> Yes but good luck getting the plugs loose without a torch. Not difficult but you will probably have to re-solder the bung.

Don't wana be around when you put a torch to that plug and soldering isn't an option IMHO. :roll:
Hal
--
1977 Royale 101348,

1977 Royale 101586, Diesel powered,

1974 Eagle Bus 45',w/slideout

 

[Ken B]

It looks like you are correct Matt. I looked it up and Aviation Permatex says to use alcohol to dilute it and also for clean up. Also the SDS sheet
says it contains 10 to 30% ethanol by weight. I assume evaporates off after it is installed.

I have used this product for years on a number of applications, but it looks like using it for a connection that will be exposed to alcohol is
probably a bad idea.

I have never had it leak gasoline but probably it should be not be used with craponol laced fuel exposure.

I do not like using teflon tape but using teflon paste would probably be OK.

Aviation fuel systems do have an inline filter or filters but in this case the filter did not catch the piece of teflon. So it must have been
installed or introduced into the fuel system somewhere past the filter. We never figured out how it got there.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

 

[johnny]

Given the current (low) price of gas, I'm going to take up Nelson Wright's approach - test the regular "May Contain" hoses and see if they maybe left
the alcohol out because of its cost.

--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

 

[johnny]

Hal, I watched a welder buddy weld some gas tanks. First he filled them with water, and as they drained he purged them with gas from his MIG system.
No more fumes, and safe to weld on.

--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

 

[Jim Hupy]

There is truly NO SAFE WAY to weld on a tank that has gasoline or for that
matter any petroleum product stored in it. There are ways to render the
fumes LESS COMBUSTIBLE, Given a set of conditions of temperature, pressure,
and contents. Using, CO, CO2, Argon, Helium, Halon, Nitrogen, or other
inert gasses to displace enough of the oxygen from the container to mostly
being not present in sufficient enough quantities to support combustion.
Then, if on that given day, you are feeling lucky or forgiven, weld away.
Some blessed individuals survive for many years using those methods. Me, I
choose to never, never, ever, weld on any tank. Your results might vary. My
method has gotten me 76 years old, so far.
Jim Hupy
Salem, Or
78 GMC ROYALE 403

On Nov 22, 2016 6:59 AM, "Johnny Bridges via Gmclist" <

> Hal, I watched a welder buddy weld some gas tanks. First he filled them
> with water, and as they drained he purged them with gas from his MIG system.
> No more fumes, and safe to weld on.
>
> --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
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[roy keen minden]

Ken is the cover in the 3:21 final vented? Back in the day we used to braze a short length of 3/16" copper tubing at the top left corner of the cover
being careful that it was shielded from oil coming off the ring gear. Never leaked with this vent and the oil up to the bottom of the fill hole. The
seals with the hole in it didn't work too well. Got this idea from Fritz Slama.
--
Roy Keen
Minden,NV
76 X Glenbrook

 

[wrightjohn 2646]

The 3.21 drive is vented thru the drive side axle flange. They have also have been vented by adding a vent port on the top of the cover and a line to a safe area. Is that a good thing to do? That I am not going to comment on. My 3.21 had a vent line blazed before I bought the coach. I was also designing an internal baffle to the the Ragusa cover, but Jim K says it is not needed.

JR Wright
GMC Great Laker MHC
GMC Eastern States Charter Member
GMCGL Tech Editor
GMCMI
78 GMC Buskirk 30’ Stretch
1975 GMC Avion (Under Reconstruction)
Michigan

>
> Ken is the cover in the 3:21 final vented? Back in the day we used to braze a short length of 3/16" copper tubing at the top left corner of the cover
> being careful that it was shielded from oil coming off the ring gear. Never leaked with this vent and the oil up to the bottom of the fill hole. The
> seals with the hole in it didn't work too well. Got this idea from Fritz Slama.
> --
> Roy Keen
> Minden,NV
> 76 X Glenbrook
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[jim kanomata1]

Fritz was great at coming up with improvements. Learned a lot from him.

> Ken is the cover in the 3:21 final vented? Back in the day we used to
> braze a short length of 3/16" copper tubing at the top left corner of the
> cover
> being careful that it was shielded from oil coming off the ring gear.
> Never leaked with this vent and the oil up to the bottom of the fill hole.
> The
> seals with the hole in it didn't work too well. Got this idea from Fritz
> Slama.
> --
> Roy Keen
> Minden,NV
> 76 X Glenbrook
>
> _______________________________________________
> 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

 

[hal stclair]

> Hal, I watched a welder buddy weld some gas tanks. First he filled them with water, and as they drained he purged them with gas from his MIG
> system. No more fumes, and safe to weld on.
>
> --johnny

I've used the method by purging with CO2 but still don't like it. Put a bottle of CO2 with a hose running in the tank for an hour before I struck an
arch, still worried me.
The first time I welded a tank we purged it with water for some time and left the tank 'full' of water thinking it should be fine. When I put a torch
to it I thought a Saturn V had just launched. The tank landed on the other side of the street and my hearing took a LONG while to recover. Been gun
shy ever since and only weld one if it's a 'hasta'.
I certainly agree with Jim's assessment.
Hal
--
1977 Royale 101348,

1977 Royale 101586, Diesel powered,

1974 Eagle Bus 45',w/slideout