Gas tank leak

[keith88]

Hi guys My charger has a gas leak in the trunk when ever i fill it i can get about a 1/2 cup of gas in the trunk it dose not leak outside that i can see the tank was replaced right before i bought it  the vent tube is sealed and gos through the trunk and dose not seem to be coming from there .It would appear that its  coming from the area where the fill tube goes though the trunk floor to the tank ,i can not see any visible holes or ware spots and it dose not leak when using a gas can to fill.  Looks you would almost have to be in the car when you take off to tell  and not sure if you can see anything when filling it and having someone watch the spot ..haven't tried that yet and it could be leaking under acceleration and it does leak for long or continue to do so after a shot time after fill up. Any one have something similar happen to them at all ?

[tan top]

 does it only happen when  you have a full tank of gas ?  

 check the  rubber vent hose  , see green arrow , also make sure the other end of the vent line  exits into the frame rail or just out side the bottom side  via a rubber hose

[keith88]

Yes, and the vent line is just like what you show but it dose not appear to be leaking from that area it seems to be coming from where the pipe goes though the trunk floor only when i fill it.  mine dont look quite like the picture you show mine dont have that piece that covers around where it goes though the floor however it is sealed. Ill see if i can get a picture to shoe you later.

[keith88]

I get gas in the area of the Black circle and little heavier and believe its coming from the area along the white circle but can find no holes any where in that area this paint job you see got all screwed up today when i put gas in it ...thought i had it fixed over the winter ,guess not.

[myk]

Maybe a helper could slowly pour gas in while you watch for where the leak comes from?

[tan top]

 thanks for the picture    

call me crazy  , could be my computer screen  , but see green arrow , is that a over lap join of the filler tube ?

   also check for rust throughs on the back side of the filler tube just where it passes through the floor ,

 I found mine was really pitted there 26 years ago when doing the trunk floor  ,   got to it just in time 

[keith88]

No it is one tube all the way though how ever it dose seem to be up against the trunk floor around the area you have pointed to the tank was new and put in right before i bought it last year i also just finished undercoating it and everything looked good from underneath as well i see no visible signs of pitting on either side of the trunk floor. How ever i did jack the back way up in the air durring the winter and got gas in the trunk ..kinda forgot about that ,but still could see where it came from.

[bill440rt]

My hunch is that it's coming from the top down. Very rare that a liquid flows from bottom up. 
Do you even have the rubber trunk floor/filler neck seal and the rubber grommet that the vent tube passes thru into the floor? It doesn't appear so in your picture.

The filler tube passes thru the floor seal, then thru another large rubber grommet into the tank. So, for gas to come up thru the bottom it would have to pass thru two seals and defy gravity. Unless, your tube has a crack in it by the trunk floor that's hard to see.

I would look for gas running down the tube starting at the top.
Or, as mentioned have a helper fill it with a gas can and with the trunk open look for signs of leaks with a flashlight.

[green69rt]

OK, I'm going to throw out a SWAG...the little piece of hose that connects the overflow tube to the fill line is leaking.  The gas runs down, either the fill tube or the overflow tube, and puddles on the trunk floor???  Something got jostled during the work and the old piece of rubber tubing developed a leak.

[bill440rt]

OK, I'm going to throw out a SWAG...the little piece of hose that connects the overflow tube to the fill line is leaking.  The gas runs down, either the fill tube or the overflow tube, and puddles on the trunk floor???  Something got jostled during the work and the old piece of rubber tubing developed a leak.

I thought so as well. See his previous post, Keith says he checked it and nope... 

[keith88]

I have checked the  vent tube numinous times and found no wetness any where near the top or around where the vent tube runs only on the trunk floor. I also tried poring gas out of a can and didn't seem to be able to get it t to do it than ,how ever it did leak out over the winter one time when i had jacked the back up way high and got some gas in the trunk that time without filling it although i cant see a leak something seems to be happening when the gas goes in the lower part of the fill tube.  Do they make a spray sealant that is gas prof?

[green69rt]

I don't know if this helps but here is a picture of my old filler tube from the bottom.   You can see the baffle that lets air back up to the top part of the filler as you poor gas into it.  The baffel goes all the way to the top, you can see how it lets air out if you look down inside the top of the tube.   I can't tell if it's welded in or press fit?   Anyway, my car was about as rusty as they come and my tube appears to be really solid, even the area between the floor seal and the gas tank seal.   So unless the tube is cracked at the bottom I can't see anyway for it to leak, I'm stumped..

Just a last question, how is the tube sealed to the floor?  I can't tell from the pictures.

[keith88]

Its hard to really say but it appears to be almost like a foam like piece that surrounds to pipe that goes though the floor and that looks like its sealed with some sort of sealer at the base ,as i mentioned the tank was replaced right before i bought it and the guy will not talk because he sold me a misrepresented car so he scared to answer his phone so i really dont know any pass history because of it . I just took some picture of it this morning maybe they will help. Remember i tried to use a rubberized undercoating to seal it that what the black color is just made a mess. the leak goes away fairly quickly dont have to drive it much and it stops .

[tsmithae]

In that last pic, the seal doesn't look terribly promising.  If it were me personally, I would be pulling the tube and thoroughly inspecting it for any pin holes/cracks.  After that I would be replacing every seal (trunk to filler neck, filler neck to tank, filler neck to quarter) and even the small hose for the vent tube.   

[Charger-Bodie]

In that last pic, the seal doesn't look terribly promising.  If it were me personally, I would be pulling the tube and thoroughly inspecting it for any pin holes/cracks.  After that I would be replacing every seal (trunk to filler neck, filler neck to tank, filler neck to quarter) and even the small hose for the vent tube.   

[keith88]

After picking at it this morning it would seem that the only seal it has  is a seam filer to block off the hole in the trunk between the filler tube and trunk floor ...I take it that aint right is there suppose to be  some sort of seal there like in the picture at the beging of the thread? Also if i pull the tube do i need a replacement gasket at the tank or can i use the old one that looks new and probably is new because it was changed right before i bought it.

[keith88]

OK after jacking the back of the car up as far as i can and after an 1/2 hr i get  gas seepage from here coming out of the seam sealer that side of the pipe looks like it might be hitting the hole on that side from underneath. Ill have to cut it all away and check for holes.

[bill440rt]

Looking at the pitting on the tube in the pic, there's probably a hole there. 

You'll need one of these, luckily they are available repro inexpensively:
http://www.ebay.com/itm/68-69-70-Dodge-Charger-Mopar-B-Body-Fuel-Gas-Filler-Neck-Tube-Pipe-VENTED-LINE-/251811492341?hash=item3aa12271f5&vxp=mtr

It gets sealed to the floor with one of these:
http://www.ebay.com/itm/New-Mopar-1968-70-Charger-Trunk-Floor-Fuel-Filler-Tube-Seal-/400886940659?pt=Vintage_Car_Truck_Parts_Accessories&fits=Model%3ACharger&hash=item5d56b943f3&vxp=mtr

And the vent tube passes thru this grommet (the tube only passes thru the grommet, looks like you have fuel line added going thru the floor). The description says C-body but this is what it looks like:
https://www.yearone.com/Product/1966-74-a-b-e-body/gr3446

[keith88]

FOUND IT. I took the pipe out and under the sealer found this ...Guess what im buying today. Thanks for the links.

[tan top]

FOUND IT. I took the pipe out and under the sealer found this ...Guess what im buying today. Thanks for the links.

  good stuff , you  found it

[keith88]

OK now that i have ordered a new fill tube and gasket can any one tell me how hard they will be to get back in.  I did not drop the tank when i took it out and it was a little tricky getting it out ,so are there any tricks i should know before i go to put it back?

[green69rt]

To me, logic says to put the tube down thru the fender and install the floor gasket on the tube.  Do not screw the floor gasket down yet.  Use some water and dish soap to coat the tube and push it down into the gas tank gasket.  The one drop of water and dish soap won't mess up the tank of gas but if you are worried just and a bottle of gas tank treatment.  Screw the top of the tube to the fender.  Push the floor gasket down to the floor and line up the holes in the gasket, mark thru the holes with a sharpie or similar.  Pull the floor gasket back up, drill pilot holes for the mounting screws.  Apply a layer of gasket sealant to the underneath of the floor gasket and to the top of the floor, push the gasket back down and screw it to the floor. Wipe up excess sealant.  Done.

[Charger-Bodie]

Only problem with that Mitch is that the flange of the fill tube is under the quarter panel top. Also any kind of solvent ie. Carb spray prep solvent ect work very very well to make rubber super slippery.

[bill440rt]

 

I wouldn't use soap/water either. I would use something solvent based, even WD-40 works very well.

Yes, the flange up top fits under the quarter panel, on the inside of the trunk. You'll have to lower the tank somewhat, put the tube thru the trunk floor then attach up to the quarter panel. Then, raise the fuel tank as you ease the tube into it.
As others said make sure you put the tube/trunk floor seal on first otherwise you'll never get it on once the tube is in place. Keep it up higher on the tube. Once the tube is in place, lower it, mark the holes, drill, & screw it down. You'll also need to have the vent tube grommet in place as well.

[green69rt]

Only problem with that Mitch is that the flange of the fill tube is under the quarter panel top. Also any kind of solvent ie. Carb spray prep solvent ect work very very well to make rubber super slippery.

Good points.  I only wanted to get some discussion going.  Thanks to all.  I thought the tube flange went on top of the quarter, not below.  It looked like this old seal was not the regular seal.  It seemed like the last thing to do was the floor seal. I still have to do mine so this is a kind of test case for me.

Do you really have to lower the tank??  Good info....  This sounds like one of those arcane pieces of knowledge that need to be spread around.

[VegasCharger]

Bill, Mitch & Brian kudos for helping Keith88

Good to see you're heading in the right direction with this mess. It's a shame that the previous owner/seller was a deadbeat. Looks like he doped up that entire area of the floor seal for the filler tube. A "Band-Aid" fix sort of speak.

Bryan

[keith88]

The whole car has been a band-aid fix so it dont surprise me, I have fixed so many half ass fixes its unreal and i still dont have any idea what i have but its better than it was. I did not have to drop the tank to get it out and i read somewhere that someone else did not have to, to put theirs in but it was tricky. That was actually found researching this forum, something about flipping it 180 at an angle than getting it in. anyone try that?

[Charger-Bodie]

You can get it in without moving the tank ,but if the hole in your floor is not the full size it should be you will want to enlarge it .both for figment and to avoid contact when you have the new tub installed.

[squeakfinder]

   I lowered my tank when I replaced the tube. But I needed to replace the tank strap's anyway so it made it easier. Only problem was the new vent tube not fitting real well. But it sounds like others had that same problem. I've topped off the tank a couple of time's since and had no leaks.

[keith88]

Looks like i found my gas leak and bought my filler neck just in time the place i got it from relisted it today for $7 more than i paid yesterday.

[fy469rtse]

I didn't have to drop tank, you can get it in with tank strapped in

[green69rt]

I'll be waiting to hear how things went and when you get the car back on the road.  Keep at it!

[keith88]

I'll be waiting to hear how things went and when you get the car back on the road.  Keep at it!

Could be a bit, hope not but i see they sent it parsal post SLOW shipping coming from Cally and going to CT could be a couple weeks ...God i hope not!

[keith88]

Well it took 8 days to make it to me...next time a pay extra for quicker shipping! It went right in no issues use a little wd-40 and it slide right in , and added the missing seal at the floor, should be good.  BTW nice piece worth buying.
Here's some shots one of the tube and the other installed.

[cdr]

that looks much better 

[tan top]

  looks good !!   nice looking product , think I might get a new one now 

[green69rt]

So much better, having gas leaking into the trunk would be a little scary to me!   Did you end up changing the shape of the hole in the floor??  Just screw the seal to the floor or does it bolt in??

[keith88]

No the hole was good, mater of fact this pipe seemed to fit better went right in ...I used a little wd40 and it slide right in. As far as the gasket I pre drilled the hole and screwed it right down  no issues the whole thing took15 minutes.

[keith88]

Filled it up today and NO LEAK love it thanks guys for the help.

[nvrbdn]

like the look. great job.