Gas fumes inside car--Tank seam is leaking

[daveegt]

I have been smelling gas inside GT after filling above half. Anter driving a while I quickly chenked behind the tail lights and found that the seam between the top and bottom halves is leaking. Has any one else had this problem and what did or could you do to fix it? I am sure that it will involve removing the gas tank. Can you help wit an idea??

[baz]

look at the vent pipes and filler pipe before anything else the wet seam may just be where its sitting if your lucky

if not its tank out to fix it

[daveegt]

I will check those, but the fuel along the seam was located along the pass side and the front right side.

If this is the seam what is the best fix??

[yellaopelgt]

Might be easier to locate a different known to be good tank.Your going to have to pull it out anyway. The other option would to have the inside coated professionally or I do believe others have used a do-it yourself sealer that you swish around inside and let dry. But to me....once a seam lets loose, it may compromise the integrity of the whole tank and I wouldnt want to risk it.
HTH
Joe
forgot to mention....its more than likely a pin-hole and not the seam,but that would indicate some serious rust inside anyway so unless you want to completely re-do the entire tank including removal of fuel sock,and getting the fuel line off without breaking it(plasic if original) You may want to go the fastest route and just find a different one. There are quite a few Texas guys down there that might be willing to locate a tank for you!!
Good luck!!

[daveegt]

Not what I was hoping to here, but it might just be the problem. The only time it leaks is when I drive it. It is wet around the seam only. I guess I will find a time after Christmas ot pull the tank and check it out.

[namba209 (R.I.P.)]

Before you go "Looney Toons" on tearing out the tank, double check what Baz said. The tank vent tubes are just above the seam and are located front passenger side of the tank and rear driver's side. It could be that, if you have the original plastic vent lines, they could be cracked at the fittings. a flashlight and mirror will be your best tools in this regard. To get "up close and personal" with the tank you have to remove the spare tire shelf and brackets, but you have to do that anyway to get the tank out. I had a similar problem on Willit?, I had replaced all the vent lines with new hoses and still had gas fumes in the car after filling it up. Turned out the filler neck hose, I didn't replace, had internal cracks and fuel seeped out of the cracks when I refueled the car.

[yellaopelgt]

Ron and Baz are correct. Check everything out before you get too extreme!!
A real good indication of rust inside the tank would be the fuel filters clogging up real quick and poor performance in general.
Didnt mean to jump the gun....sorry!!!
You will be removing the spare tire shelf to get good access to the vent lines anyway and the first thing to do would be replace them, ALOT of us have had to do this for the simple fact that they are pretty crispy after 30+ years!! But....once the shelf is out and you can get a better looky see to what is really going on, removing the tank is a fairly easy job. BTW there are 2 nuts inside the rear wheel wells that are usually covered up by undercoating,(1 on each side)you will need to find them to remove the shelf.Those are the ones that usually stump people that have never done it before. Do one vent line at a time,remember the routing(some years are different)and HOPEFULLY thats what the problem is!!
Good luck!!
Joe

[jvandyke]

BTW there are 2 nuts inside the rear wheel wells that are usually covered up by undercoating,(1 on each side)

On my '70 there's two nuts holding the spare tire bracket on the passenger side wheel well only, nothing on the driver's side but mine was missing various pieces. And yes, I got caught on those bolts my first time, took a bit to find the nuts. I've not removed the tank so any hidden nuts for that are still hidden for me.

PS
I've been fighting gas fumes for a year now, did vent lines, fuel sending unit gasket, redid vent lines to check that the small T fitting was pointing to filler neck but still have fumes, so either I need to replace the filler neck rubber section or the tank itself is letting fumes/fuel out somewhere. (that or my fuel sending unit re-seal failed since two of the bolts had stripped the threads and wouldn't grab, I figured three of 5 wasn't bad but maybe it is, I used sealant too, that was/is certainly part of my problem since at one point the top of the sending unit was wet with gas). Oh and the PO had eliminated the vent line/charcoal canister and left that line open to the air near the rear axle, that's outside the car and doesn't really explain the inside fumes but replumbing that is on my to-do list too!

[yellaopelgt]

Ya know....maybe there is only the 2 on the one side....hmmmmm...been a while since I did it. I'm just gonna shut up now, I keep sticking my foot in my mouth!!

[namba209 (R.I.P.)]

O.K., guys, I had to go check Willit? to be sure. On the passenger side wheel well there are four nuts and washers, on the driver's side there are two. The vertical ones are for the spare tire hold down bracket, the horizontal ones, in each wheel well are for the tank supports. Don't want to get anyone confused here. To remove the spare tire shelf only the two vertical ones need to be removed, to remove the tank, it is not necessary to remove the horizontal ones, but you do have to remove the four bolts that hold the tank on to the supports. HTH.

[daveegt]

Thanks Ron for your input, I had originaly pulled the vertical panel below the tire cover and saw the gas on the seam. I went back and bent down a little further and saw the vent in front right top, there was NO line at all, but that's a good thing I just got this GT on the road after restoring it and filled it up for the first time when I noticed the gas smell. I am sure this is the problem, but where does it go, to the canister, I can't find any trace of it. Thanks again Ron you have saved me alot of work. I'll find a way to run another line when I figure out where it goes.

[namba209 (R.I.P.)]

Looks like you need to replace the vent lines, which means you'll have to take out the spare tire shelf. I don't know if it's still on the site, but do a search for the "fuel tank vent lines". There are a few threads that cover this and their routing. There was a project or tech article on this too. It may have been disabled while Gary is renovating the site to a new server. Off the top of my head, there are two "T" fittings, one that goes to the filler neck with a smaller orifice towards the neck and one that connects the two vent lines from the tank to that "T" and goes forward to the charcoal cannister. HTH.

[daveegt]

Found the vent, and someone before me removed the entier line in the tank area. I got it replaced and no more gas smell in the car. This was much easier to fix than pulling the tank. Thanks for all the input form all members.
Dave

[GTJIM]

Good that your fumes are under control - but it is always an idea to keep your eyes open for a good replacement gas tank as pin holes can appear due to the age of them. No need to got to extreme lengths to find one - just keep your eyes open locally as they are very difficult to ship.