Odd gas tank situation

[Matt Colie]

> > The intended purpose of the mystery fitting in the side of '73 and some '74 coaches has never been identified.
> >
> > If there is any fitting in the left rear of the main (rear) tank, that probably was a generator feed at one time. It is quite possible that
> > it had a pick-up tube in it at one time and that may now be rattling around in the tank. It would be simple (and smart) to solder an new piece in
> > there. I had to resolder my generator pickup.
> >
> > Matt
>
>
> It's purpose has been identified. It is the liquid return fitting for the first try as vapor separation. That system apparently did not work
> very well and was replaced with the float system very early on. The tanks spec's or the tanks themselves must have already been finalized. So now
> that nipple is on a lot of tanks. I could be used as a fuel return port.
>
> This a picture of that early fuel vapor system.
>
> http://www.gmcmhphotos.com/photos/fuel-tank-r-26amp-3b-r/p13484.html
>
>
> If you are doing internal tank sealing/ coating make sure the generator pickup tube doesn't become clogged.

Thanks,

I had not picked that up.
Too bad that they didn't run a CFD on the system like I did (on my personal computer 30+ years later), they would have known it would not work. Now
all I need is to repair/replace that stupid float valve again.

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

 

[j artz]

Okay. Verified there is a generator fuel pickup tube inside the tank, welded to the boss the brass fitting threads into. A tube attached to the
fitting makes more sense, since it could be easily repaired or replaced, but at least there's a tube. No sign of any breaks or holes in it, so I'll
check it with a mityvac once the tank is clean.

Put 5 gallons of E85 in the main tank to soak (the alcohol does a great job cutting the varnish buildup), and 5 gallons of cleaning vinegar in the
auxillary to cut the rust. Tomorrow we'll see what happens when I turn the tanks, hopefully there still won't be any sign of a leak.
--
John in Omaha, Nebraska
74 26' Sequoia

 

[j artz]

Turning the tanks every 24 hours, leaving them sit so each seam is wet for a full day. Still no sign of seam leaks. My suspicion is that a hose leak
on top of the tank ran down and looked like a seam leak to the PO. If the derust rinse works well enough, they'll get a couple coats of paint on the
outside and then back in.
--
John in Omaha, Nebraska
74 26' Sequoia