Question about large dealer installed gas tank

[1956cameo]

My 72 suburban has one of those large home made looking gas tank that was dealer installed. It is the type that has large carraige bolts that go thru the floor and the tank. For all the other people on here that have the same tank I have a question.
When I got my suburban the tank was taken out and the rubber lines were missing. Well thru piecing the rubber lines that were in the back of the suburban together I was able to figure out where they all went (I thought). Any how I put everything back together with new lines but now when I try to fill up the gas tank with gas it burbs horribly spitting gas out onto the ground. Does anyone know where all the lines are supposed to go. It had 4 or 5 vent lines coming off of the top of the tank but they obviously aerent working.
Also does anyone know what I could do to simply cut a line so it can vent without it having gas splash out. Any info would be greatly appreciated.

[4x4Poet]

There may be an expansion tank on the drivers rear behind the interior panel. If there, did you route hoses to it?

But I'm confused (easily, no doubt). If you had the tank out, how could it leak through a hose if you put an new hose on every hose nipple? Maybe the sender/pickup or something else is leaking. Loose hose clamp? leaking filler hose?

I'd guess you'll have to drop the tank and check for signs of fuel leaks but try checking the filler hose first.

[1956cameo]

Wow! I asked this question almost 4 months ago and finally got someone to respond. Yeah, I am confused as well. Once the fuel is in the tank there are no leaks, its just not letting air escape the tank properly when I put gas into the tank; thus causing the air to burp out and spraying gas all over the place. The only thing I can think of is that I routed the hoses wrong, but didn't know if anyone else had any suggestions or a diagram of how the hoses should go.

[vectorit]

My burb had a second tank installed back in the day, and it was just another stock style mounted forward of the other. The stock fuel fill pipe was cut/welded as a Y pipe, it was always a PTA to get fuel in the front tank so I took it out during the resto.

Does your added tank have a dedicated fuel fill pipe? Or does it share the original like mine did?

If it is a Y pipe, I would have to position the fuel nozle in a way that would allow the vapor and escaping air to get by. Since the vent tube was later found to be pinched.

Not sure all this helps you at all. It just reminded me of the hassles I went through with mine, and in the end just took it out and made everything factory style.

Good luck!

[1956cameo]

Thanks Vectorit, My fill line does not have a Y, the tank that is in it is the only one. What happened is they took the factory 20 gallon tank out at the dealer and installed a 45 gallon tank. Not sure who made them but I have seen quite a few of them on this forum, and my father in laws 4x4 burb also has one of these tanks.

The vent line isn't bent that I know of, and as far as I thought all the lines were hooked up properly. Maybe these tanks just burped alot when filled. I might just have to find a way of filling it up without causing it to burb. Or fill it up very slowly which when you are filling 45 gallons could take all day to do!

[Hart_Rod]

Could you take pictures showing what you have hooked up?

[1956cameo]

Here is a picture of the gas tank before I re installed it not sure if it helps at all (I doubt it will help). You should be able to see the metal nipples that come off of the top of the tank I think there were 3 or 4. Unfortunately I do not have any other pics of the lines because before I installed the tank since I was not expecting there to be problems down the road. If needed I will drop the tank to get better pics.


Of course after loading the pics I see that the nipples are all on the other side of the bar laying on top of the tank.

[vectorit]

I meen no disrespect there buddy, but why would you want to keep that? It's lookin nasty on the outside, and I can imagine what it looks like inside. If you have your heart set on a big tank, ya might be better served by havin one built to order. In that case you'd know how everything would work.

In my case I just tossed the dealer mods, and just went simple OEM style tank. But then I am not DD my burb, just fixin her up for fun.

[Tim Christian]

My Burb had one just like it. I caned it and installed a factory one.

[1956cameo]

Hey everyone. Yeah I know. Most of the guys that saw my suburban thread when I got it told me to ditch the dealer tank. Believe it or not when I took off the sending unit to check out the inside of the tank I was quite suprised. The inside is spotless and is nothing but shiny metal.

The reason why I am trying to keep it is because money is tight and I don't have the $200 dollars for a new tank. Also I have not seen any of the factory tanks for sale used that are worth cleaning to put on there. Trust me when I get the funds the stock 20 gallon tank will be installed (mainly due to the fact I can't put a trailer hitch on with this big tank). I am just trying to get her to work as best I can until then. No disrespect taken, all thoughts and input are appreciated.

[project 67 sub]

my sub had one like that to and i also canned it cuz it was to big and rusty inside. so i got a 31ish gallon one fom a 75 suburban and put it in its place.

[moonshinner]

did you have to do any mods to the tank to to make it work when you put the 72 tank in i want to put a larger tank in my 68 suburban

[project 67 sub]

i had to cut more of my floor out, remove the crossmember in the frame and make a new one farther back, i also cut the floor brace above the tank, and i installed the tank backwards for now. but then again i dont have much of a floor left anyways as im in the process of bagging it

[4x4Poet]

See the vent line coming out of the top of the tank half without the sender/supply line hole in it? Obviously, that vent line is meant to allow air (fumes) at the top of that half escape as you fill the tank.

So, where does the line coming from that vent now terminate?

[1956cameo]

Good question 4x4 poet. It has a vent/fume line next to the filler line; but I cant remember where it goes into the tank at. I will check it out when I get home and post where it goes in at.

[jimbug]

huh.... I thought my tank was a one off custom! I personally love the 45 gallons cause it will last all week.
mine leaked when too full, it had a rotten hose somewhere and I asked a buddy about deleting all of the spagetti mess from above the tank and he seemed to think that was a bad idea... probably would make it burp like you are experiencing!
wow that would suck cause it already takes forever to fill!

[1956cameo]

Jimbug, Yeah, I am pretty sure that I put that spagetti mess back together wrong and thats why it burps. I too thought at first that my tank was a one off, but soon found out that many others had the same tank. My father in law picked up a 72 burb 4x4 that also has the huge 45 gallon tank.

[Beelzeburb]

Hmm, mine is a bit different. The vent and return lines are all on the side of the tank instead of on top of it.



I also don't remember having any sort of vapor recovery/expansion tank to deal with, but its been years since I removed this thing. I've since gone to an EFI tank from a later Blazer but that is its own mess of tubing.

[prairewolf]

1956cameo, I have a the paper work schematic for the Sub Travel tanks, I will mail you a copy if you like.... it shows simple instruction of tying into stock vent tube. pm me if you want one.

[1956cameo]

PM sent Prariewolf. Beelzeburb, that is interesting. Other than that our tanks are identical.

[jimbug]

I sent you a PM too Prariewolf. What a wealth of knowledge this site is! I tell you what!!

[1956cameo]

Thanks jimbug. I have to agree with you on this site. Before I was a member here I considered myself an expert on chevy trucks from 1947-1972. Now I have realized my education on these vehicles has just begun. This is definately the best site on the web for classic chevy truck info.

[prairewolf]

I mailed that schematic,..... looking at that tank picture in this thread and thinking about it, the rather flat angle of filler neck maybe causes the filler tube to be overwhelmed by gas and it burps,... a work truck I saw one time that was modded, with a flat bed, had to be driven up on small piece of wood, to put a downward angle to fill tube. and then it would fill easily.

[prairewolf]

the short answer to my above post is that it may be the fill angle and not the venting at all.

I will shut up and go to work now.


life is good,kent

[1956cameo]

Thanks a million Prariewolf!! Got the schematic from you the other day. It was exactly what I was looking for. Havent had time to work on the burb yet but the way I hooked the hoses up looks different than the schematic. At least now I have something to go by. I will let you know if it works out. Once again thanks, this will really help.