wagon gas tank Qs

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jon510
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wagon gas tank Qs

Postby jon510 » 17 Jan 2015 21:58

I'm trying to figure out what my gas tank situation will be as I'm going diesel.

I got under the car today as I was draining the tank to see what my options are. My haynes diagram depicts two nipples that look like and inlet and outlet in addition to all the vents that come off the tank; crawling under the tank I have a pretty good view of the top, where I can clearly see the fuel feed to the engine coming out but no fuel return. Some of the posts I've read detail having a capped return to the tank next to the outlet, but I don't see one. This would obviously be handy to have.

Also, I'm contemplating the need to have the evap tank behind the trunk panel on the passenger side. Going diesel, I shouldn't really need a tank to deal with evaporative losses. I was thinking the early tank setup might be simpler to run, as long as I could find one along with a filler neck.

I've done some searches of the site and google without finding much detail on the wagon tanks. So hoping someone can help me out here before I undertake the nasty job of removing the tank. Questions:

1. Does the early style tank bolt up if I want to get one and remove the evap crap? Assuming I can find one.
2. Do all the tanks actually have return nipples on them? Or is this not uniform? I'm obviously looking at dropping the tank but after reading a bunch about this I'm getting a bit wary, sounds like a terrible job.
3. What are the wagon EFI guys doing for a fuel return if I'm right and there is no return nipple? Getting someone to solder a new nipple on?

I figure I can probably use a vent temporarily for a return should I decide to remove all the evap stuff. Just thinking it would be nice to have a proper drain, so likely the best option is to pull the tank and get a proper nipple soldered on. But I'm hoping to just get a bit more info before pulling it all apart as to what I should expect, I was hoping to see a return nipple next to the outlet as my diagram suggests but I don't see one.

Thanks!

Jon

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Byron510
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Re: wagon gas tank Qs

Postby Byron510 » 18 Jan 2015 07:49

Hi Jon, you're correct -the whole evaporation system is not required for the fuel system in a diesel. And you'd be wise to remove all of the piping associated to it. On a wagon there is 16mm vent hose that also passes through a specific hole in the structure of the rear of the car. This vent line hose is prone to rotting off and then you have a nasty leak. The worst part is that this vent hose is in a horrible spot to get to. So its a very good idea to remove the tank, delete all of the evaporation system to simplify your installation and replace all rubber lines and you then know it's done. Then block off all of the unused connections to the tank by having them welded up. It used to be that most radiator shops would perform this task as they had the caustic tanks to boil out and clean your gas tank before welding (or boom!). But now adays those shops are nearly gone with the aluminum radiators now being produced. You might want to call around.
I am sure there is a fuel return line to the tank though. Me EFI wagon was a 70, and it had a return line.
Byron
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jon510
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Re: wagon gas tank Qs

Postby jon510 » 18 Jan 2015 10:13

Alright, I'll get to work on pulling that tank. Was kinda hoping I could avoid that job but looking less likely, especially if I want to delete the evap system.

Is the return nipple right next to the feed on the top of the tank? That's where it appears on my diagram, although you can't tell if they're on the top or the bottom of the tank. Wrestling around under the car, at least the one appears to be up top, unless they're in separate locations.


J

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okayfine
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Re: wagon gas tank Qs

Postby okayfine » 18 Jan 2015 12:45

DQ 9.1 has a whole article about the wagon tank and evap systems. Differs between early and late series.
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jon510
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Re: wagon gas tank Qs

Postby jon510 » 18 Jan 2015 15:15

I've gone through that article, helps for replacing all the evap stuff and stretching the filler tube but there really isn't much there on the supply/feed lines. Both early and late diagrams show a supply and feed nipple though. I guess I'll just have to drop the tank to see if there's a nipple I can't find while crawling around under there. I guess I can temporarily use a vent as a drain and cap the rest of them until I get a proper nipple welded on it it's indeed missing.

Jon

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Byron510
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Re: wagon gas tank Qs

Postby Byron510 » 18 Jan 2015 22:33

For the PM's from Wagoneer and Jon, I hope the photo below can assist you.

Vent connections are labeled in green

Lower vent hoses labeled in red

Fuel and return lines in yellow

The parts labeled '26' are the hoses to the evap tank, and one of these hoses (or both maybe - memory if failing...) passes through a hole in the unit body not much larger than the hose. These are a royal PITA to change with the tank in place, and is best done as a major work project with the tank out. If you are keeping the evap tank, I highly suggest these hoses be exchanged for new using fuel compatible hose (not heater hose). You'll only do it once.

Jon, for your project, I too cannot see the relevance or need for this evp tank in a diesel application. If you are dropping the tank to get it cleaned, having block off hoses (not even sure if this size is available) or better yet just have the outlets removed and a plate welded over the holes and you know that it's done.

HOWEVER - don't make the same mistake I did on my EFI wagon. The tank NEEDS a vent!

Story time:
I left my gas cap behind at a gas station when I had my '70 2.2 LZ EFI wagon. I thought I'd be a hot shot, machine up a custom aluminum gas cap. I did and it did look great, BUT HAD NO VENT HOLE. In my 45minute commute home from work that night - sporting my nice billet gas cap and being all proud of myself, - I collapsed the tank so badly that it imploded on itself and actual cracked at the horizontal seam, but the car did not stop running. The old Nissan 200SX pump that I recycled into the car just kept on going. I did hear one “PONG” on the way home, just thought I’d run something over that flicked up against the car – didn’t think anything more of it. When I got home and out of the car, I could smell gas. Saw a little puddle under the car, and bend down to take a look at the bottom side of the tank. It had literally folded in on itself from every angle I just looked at it in awe, and it took a little while for it to sink in what had just transpired. I removed the inner trim panel and placed a halogen light near the filler hose to get the rubber warm enough to un-pancake it as it too was squished absolutely flat.
I took the gas cap off, took it to my little drill press at home and drilled a #50 hole in it as a vent then put it back on the car. Not knowing what to do about the tank capacity since it must have been down a third, I figured I'd just take an airline and put some pressure in the tank to "pop" it back out.
Well that did successfully pop the tank back into its original shape - more less. And then it was spraying gas out from about 8 different holes caused by the folds when it collapsed! I was screwed. It looked like a lawn sprinkler. The car was my DD at the time, and I think I spent the evening fiberglassing up the tank from the bottom side to get me by until I found a replacement. That replacement tank is the one that I put the new larger pick up tubes in. It was a live and learn event for sure.

Byron
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wagoneer
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Re: wagon gas tank Qs

Postby wagoneer » 19 Jan 2015 11:15

Byron you're the type of warrior that fuels my continual attention on the Realm and other places and people; posting and explaining well your experience is invaluable. This, as I believe you know, aids immensely to someone like me who doesn't have as much experience with cars. What not to do is in someways more helpful than the other way around. Thank you kind sir, Wagoneer

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Re: wagon gas tank Qs

Postby wagoneer » 22 Oct 2015 21:55

okayfine wrote:DQ 9.1 has a whole article about the wagon tank and evap systems. Differs between early and late series.

Thank you,
I need to look at this article......FYI wagon coming home from the paint shop soon, and leaf springs too will be re-arced. Then reassembly should be great...thanks for all you help Julian

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Re: wagon gas tank Qs

Postby 510rob » 22 Oct 2015 22:25

awesome story - arrrrghhhh!


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