Fuel lines go into the roof?

[soopernaut]

I removed the fuel tank from behind the seat yesterday and noticed 2 rubber hoses that go up into the roof. Is this how the tank was vented from the factory? If so do the vapors just collect in the roof area? This doesn't seem very safe.

Also why do I have 2 lines going up there? One was connected to the top of the tank, the other runs under the cab to the engine compartment and then is capped off. What was that for?

[OleRed66]

At least on the '66, the fuel line runs along the frame, passenger side, up to the fuel pump. There is no line heading into the roof on mine. That is strange indeed.

[soopernaut]

At least on the '66, the fuel line runs along the frame, passenger side, up to the fuel pump.

I have that as well. By the way mine is a 70. I do have 2 extra tanks and a bunch of capped lines under the truck but these don't seem related since they are running to the factory tank.

[surfnuke9]

the tank in my 71 wasnt vented at all. You sure they were for the fuel tank? Maybe left over from an old air horn or something?

[juddoats]

soopernaut my 71 had the same thing...i dont remember exactly...but one of the linges when into a long round cylinder that was up there and the other im not sure....but mine had the same thing you are talking about

[tinbasher]

it runs up to the roof then loops back down through the floor and (i think) back to the fuel system somewhere.

bob

[MOPAT]

Pretty sure the line going up was a vent for the unvented gas tank.
Air has to get in somewhere since the original gas caps weren't vented IF I remember correctly.

[nfury8]

I have been chasing caps for my tanks recently and noticed the parts stores list a vented cap for
1970 and a non-vented cap for California emissions. In 1971 I just see non-vented caps.

My 70 crew was a military truck, it has a vented cap and no vents on the tank.

My 71 Adventurer SE had a vented cap on it, but it has a vented tank. It has a single vent that
runs out and along the frame rail, like the fuel line. It dumps into the breather on the passenger
side valve cover. I will have to go look closer to see if it runs up towards the roof. I am guessing
this is in the rear pillar? I could see how it might go up and then loop back down as a trap to keep
liquid fuel from sloshing into the vent. The vent on Fury works kind of like this, it loops up and
through the trunk and then back out the floor as a trap.

[Hobcobble]

I removed the fuel tank from behind the seat yesterday and noticed 2 rubber hoses that go up into the roof. Is this how the tank was vented from the factory? If so do the vapors just collect in the roof area? This doesn't seem very safe.

No wonder the headliners fell off the roofs of our trucks.
My '71 D100 had the same set up. I bought a replacement gas
tank from a fellow member and it also has two vent fittings
on the tank. I'll tee them, run a loop into the rear pillar and
then dump the vent line through the floor.
John

[OregonDodgeboy]

If so do the vapors just collect in the roof area? This doesn't seem very safe.

Maybe a secret government plot to reduce the number of smokers?

[Cageman]

The cab on my power wagon was a 70, it had california emissions and it had a cansiter up in the pass side roof pillar, it had a long charcoal canister in there to take away the gas smell. I deleted it all as the tank is in the box. Only one that I have owned like that.
Not a bad idea. I never filled the gas tanks full on a hot day, as it would try to push it out of the gas cap, this I suppose would prevent that. 80's cars all had that, but I dont think they do that any more, charcoal canister that is, at least all the new stuff I have been around.

[shdnobetter]

The loop was indeed a trap. It allowed any vapor that condensed to drain back into the tank as well as kept liquid from sloshing its way into the charcoal canister, which would quickly render it useless. I don't know about you guys, but I kinda get the willies thininkg about all the potential for gas fumes inside the cab with all the various connections involved. My truck has the same setup, and I'll be removing almost all of it and routing the tank vent to the outside with a fuel filter attached to it.

[soopernaut]

I couldn't really see up into the pillar to figure this thing out. So it goes to a cannister and the other line comes out of the cannister and goes under the cab to the engine bay to the breather? The line in the engine bay is capped on my truck. How do you remove this thing from the pillar? I may just leave it if it is difficult to remove as I'll be removing the tank from the cab anyway.

[shdnobetter]

The line going to the engine compartment attaches to the carb. bowl vent to capture fumes generated there. I haven't looked for my canister, but as mine is a CA truck, I'm sure it's there. There is usually a solenoid valve involved as well, that opens when the engine is started, and routes vacuum through the canister to pull the fumes into it. Working from memory here, as it's been a while since I had to have anything smogged. As far as I'm concerned, a filtered vent line routed to the outside of the cab should be fine. The filter should be located higher than the tank, though, just to be safe.

[nfury8]

I know Dodge has used charcoal canisters up into the early 2000s. Haven't looked that close
at anything from the last few years, but I imagine they still use something.

[asf93555]

From my '71 manual supplement

[soopernaut]

Is that picture supposed to be for a truck. The tank looks nothing like that but it could be just for reference. If I remember there is only 1 line going up and one coming down. The one in the picture seems to have a few more lines.

[nfury8]

A month later... I finally remembered to take a close look at my 71.
It has 2 vents on the tank, one at each end. The vent by the filler
uses a short rubber hose to connect to a hard line that runs across
the top of the tank. Then both vents convert to rubber hose. 2 rubber
hoses go up into the pillar and only one comes out. That line then
runs down through the floor and parallel to the fuel line along the rails.
It finally comes up in the engine compartment and dumps into the
passenger side crank case breather, on the valve cover.

Anyone else have 2 vents on their tanks? At first I thought maybe my
truck was late production, but it doesn't appear to be. The earliest
sequence number in the registry for a 1971 is 300376 and the latest
is 381756. My number is 330005. It isn't California emissions either.

[sweptliner]

i have the same set up in my 70 D100, its become quite a hassle to figure out as i am trying to install a summit racing fuel cell.

[nfury8]

What size cell? and where are you mounting it?