gas tank vent

[fastride]

I know this is problem a dumb question but I just had to put a new gas tank in my 76 and it has two vent barbs coming out of it where my old tank only had one. Where does the other one go to.
Thanks

 

[chuck]

I don't know what tank you have so can only comment on my and hope that helps. you should have a 5/8" vent tube near the filler tube, a -AN fuel out and a -AN vent. The vent should go to a expansion tank then to a charcoal filter. If you have a 2ed vent on the tank it woul not be needed for the main tank so just cap it. Over the years many have removed the expansion tank so now you have to deal with that if your was removed. PS some EBs did not come with the expansion tank.

 

[fastride]

Mine has the filler tube and then the over flow tube that goes from the filler neck and back into the tank. Then it has two small vent connections coming out of the tank. So coming out of my new tank, there is the filler hose then the overflow connection and then two small connections. My old tank only had one small connection coming out of the old tank. I connected one of the small connections coming out of the new tank to the old hose and plugged off the other connection on the new tank and now my gas cap is building up pressure and gas is coming out of a plastic tee that is located on the frame just in front of left rear wheel. Looks like the connection that I plugged off needs to be venting some where.

 

[chuck]

Try connecting o the other vent port. If it still has tank pressure the vent system is plugged. Follow the vent line and watch for kinks or plugs.

 

[DirtDonk]

Was your old tank a stock steel one fastride? Do you have the plastic charcoal canister on the firewall, or the steel one on the frame?
If the plastic one, that would explain the single vent. As Chuck said, it sounds like it might be clogged or plugged. Maybe at the engine compartment end if the canister was removed?

What month was your '76 built in by the way? If you still have the door latch pillar decal, it'll be on that.

Thanks

paul

 

[fastride]

Mine was a stock metal tank and I replaced it with a new metal tank. There is not a canister on the bronco. I guess the person that had it before me took it off. Also, we have one of those pick-a-part places here and I know this has been discussed more than once but what different vehicles can I get a charcoal canister off of. Will any canister work if I can make it fit or is there something special about different ones. I am not sure what month it was built in as it has been repainted and the tag is gone.

 

[DirtDonk]

Should be able to find a compatible one (if not exactly correct, at least usable) from any late seventies to late eighties car or truck. There were probably only a few part numbers of the vertical plastic tanks that were introduced during the '76 model year for the Bronco. Already on the cars and full-size trucks I think, we didn't get them until '76.

Someone should post a pic of one soon I would think. There are lots of pics around the forum, including some of mine! But I'll see if I can find them on this jumbled computer I'm using right now.
But if you've seen one, you've seen them all. In fact, they're still available new from the local auto parts stores, Summit and Jegs, and the like.
The junkyard is normally a bit better sometimes though, as it's easier to find the "mushroom" caps that were used to keep debris out of the one large port left open to atmosphere. Usually the new ones don't come with, and they seem hard to find based on the normal descriptions. Someone here has part numbers too I'm sure. I've seen them posted up before.

Paul

 

[DirtDonk]

Oh, and like I think was said, you would only use one vent tube with that type of setup, so the second one just gets capped off.
The 2-port setups were used from mid-'70 to early'76 Broncos, so that's what the tanks are mainly made for. You just get the "bonus" second port for free!

Paul

 

[tirewater]

Just FYI, the canister mounted on the firewall above the heater lines going into it. The EVAP used a metal line from the fuel tank to the canister. The metal line may still be in your truck depending on how much the PO removed. The connections from the metal line to the canister & fuel tank where sections of vacuum hose.

 

[Rustytruck]

Your 2 small vent lines would be hooked up to a vapor recovery bottle. One vapor line to the recovery bottle. The second small line would be hooked to the liquid return line from the vapor recovery bottle. That way only vapor would go on to the charcoal canister and liquid back to the gas tank. Its isn't good for the charcoal canister to fill with liquid fuel.

 

[DirtDonk]

He's got a '76 and it had only one tube originally, which means he should not have the recovery tank behind the seat. Instead would have the plastic tank on the firewall and an anti-rollover valve on the frame rail, like the '77's had.

But that's a good question to ask fastride. We've been (I've been!) assuming your '76 indeed had the firewall mounted charcoal canister. But do you have a panel behind the driver's left shoulder that's hiding a plastic tank by any chance? If so maybe yours was in the transition period. But curious if you have the condensing tank there.
You can also look up under the driver's rear wheel well at the panel behind the fender to see if the oval hole is still there with the rubber grommet and plastic tubes coming through, or if it's there but blocked off.

Either way though, as mentioned you just block off one of the vents for the new-style canister system and call it good.

Paul

 

[Rustytruck]

The new tank he used may be compatible for all the trucks except maybe 1977 when they went to another plastic tank. Much easier to have an extra nipple than stocking a whole series of tanks.

 

[fastride]

Mine does not have anything in line that comes from the tank to the firewall. I am guess that the PO took everything off. It does have a plastic tee where I would think that a axillary tank would have went to. My tank is building up pressure as when I take the gas cap off, it has pressure on it. I think the line going to where the charcoal canister was is probably stopped up. I am going to try and blow that out tonight. We have one of those pick-a parts where I live and I am going to try and find a used canister today. As long as I can get it to fit, will any kind work?

 

[DirtDonk]

Probably. From that vintage they were most all virtually the same. But even with some minor differences in fittings they were functionally the same.

One line from the tank(s) to the canister.
One large port open to atmosphere, but covered/vented to keep debris and moisture out.
One large port to the air cleaner.

Nothing else unless you have extra needs. There are usually 2 or 3 small ports, but extras can be capped off.

And anti-rollover valve can be purchased new from various sources. Not sure exactly where and don't have part numbers. A few members have done them though, so might be able to help there.
In fact, I think you can even still buy the factory style at an auto parts store. Assuming the parts person knows where to look.

Paul

 

[Glass Pony]

And anti-rollover valve can be purchased new from various sources. Not sure exactly where and don't have part numbers. A few members have done them though, so might be able to help there.
In fact, I think you can even still buy the factory style at an auto parts store. Assuming the parts person knows where to look.

Paul
Paul

Here ya go on the rollover valve.

http://store.delorean.com/p-6703-roll-over-valve.aspx

 

[fastride]

Thanks on the roll over valve but I was looking for a charcoal canister and found one today at a pick-a-part and it was $9.00 plus tax and it was off of a older Explorer. I think in the mid 90's

 

[Glass Pony]

Thanks on the roll over valve but I was looking for a charcoal canister and found one today at a pick-a-part and it was $9.00 plus tax and it was off of a older Explorer. I think in the mid 90's

You did good. I think I paid around $60 from Rock Auto for one from a 1991 Mustang.

Here's a hose that I used if you want to vent your canister to your air filter housing. (that's if you are running a carburetor.) Gates #28092

http://www.rockauto.com/en/moreinfo.php?pk=100017&jsn=318

 

[fastride]

I need to get one of those. I was going to use a 3/4" heater hose and attach it to the air cleaner some how. It is a factory air cleaner housing and was wondering how everybody else attaches the hose to it. I was going to drill a hole in it a put a hose barb fitting in it.

 

[Glass Pony]

I need to get one of those. I was going to use a 3/4" heater hose and attach it to the air cleaner some how. It is a factory air cleaner housing and was wondering how everybody else attaches the hose to it. I was going to drill a hole in it a put a hose barb fitting in it.

I'm running an aftermarket air cleaner and it had a knockout for it but I believe your stock air cleaner has a place for it.
I'm sure somebody will chime in with the location where it goes to.

 

[DirtDonk]

Yeah, stock air cleaner does. Should be a black plastic hose fitting coming off of the back side of the lower lower round filter housing. At least that's where most of the earlier ones were. Maybe one of the '76/'77 gurus can confirm.
Basically same size as the fitting on the charcoal canister, but with ribs for hose retention. Earlier models didn't even use a clamp up at the filter, but I believe that later models used a clamp at the canister. At least some vehicles did. Not sure about the Explorer or the stock '76.

The original hose was not as metallic as the hose linked to, but did have metal reinforcing. Looked like it was made of paper, which it might have been. The one in the pic looks more like heat riser tube from exhaust manifold. But at 3/4" diameter, they probably just used a stock photo of the larger one.

In a pinch, a piece of standard 3/8" rubber hose will actually slip inside the fittings, rather than wrap around the outside.

Paul