68 dart gas tank leak

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1968 Dart 270

1968 Dart 270

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Hi everyone. I just bought my 68 Dart a couple weeks ago. I got tags for it yesterday and took it for a drive and noticed the smell of gas. Got it home and looked underneath and there is gas dripping from the bottom of the tank. If I remember correctly isn’t there a little rubber plug under there that cracks and leaks? Especially with the stupid ethanol fuel we have today that attacks old rubber? I have my clean clothes on and have to go to work so I haven’t been able to crawl under yet too look at it.
The engine also devolved a bad miss going home. Turned out two of the plug wires touched the manifold and burned off! (It’s a v8..supposedly a 360). It’s always something,huh? The engine idles smooth as glass and seems to run well,but it doesn’t accelerate as it should. It looks like someone put an Edelbrock intake and carb on it. I haven’t checked the timing or anything and the carb might not be dialed in. I wish people would just leave things alone. Unfortunately it seems like many of these cars are modified because people want to race them or make hot rods.
 
We need more info. There is no "rubber plug". There is a gas gauge sending unit with a rubber "O" ring and a filler tube with a rubber grommet.
 
Murray said:
We need more info. There is no "rubber plug". There is a gas gauge sending unit with a rubber "O" ring and a filler tube with a rubber grommet.
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Sorry,this is my first “a” body mopar. I’m mostly familiar with “Forward Look” era mopars.
 
If the tank is less than 1/2 full it might be a hole in the tank.

If it is more than 1/2 but these than full might be the sender gasket.

If it's full it might be the filler tube gasket.

My 67 Dart a couple of years ago finally gave up the ghost on the origional filler tube gasket.
 
If you find you need a new tank Spectra makes a nice replacement. 65"
 
Thanks guys. When I get home from work and can get under it I will post some photos. I filled the tank up to the top yesterday because the gauge doesn’t work. I drove around about 30 miles and noticed the leak when I got home
 
olkingcool said:
i have tank with sending unit out of ny car went efi
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Can you post a photo of it here? I won’t be home until this evening to jack the car up and go underneath and see where the leak is. I’m fairly sure it will be the sender area. It’s leaking down under the middle of the tank. I know the ethanol in the fuel ruins older rubber seals. The stupid stuff also causes the cars to get worse mileage. Don’t see the point in it
 
Some days you get lucky and find the sender lock ring just needs a little persuasion in the tightening direction to stop the weep.
 
ALL, let me repeat, ALL aftermarket senders are junk. They will go in and with the OEM lock ring seal and work.


But the gauge WILL NOT read correctly.


IMHO

before you spend any money on a new sender pull yours and see what's it looks like.

There is a how-to artical on repairing certain problems with them.


Also there should be a ground strap that routs the ground og the sender around the rubber hose to the fuel line for grounding. Without it sender will not work.

Also maybe your gauge is bad!

Buy a sealing gasket or get one from a wanted ad here on FABO.


My experience is the gaskets are thinner and the aftermarket lock rings are thinner as well. So be sure to keep your OEM parts.

The OEM sunder can be sent out for repair.

Lastly, and many will try to talk you out of it, buy a propper sender lock ring wrench, cheap but well worth it.

It makes getting the sender, gasket and lock ring on and aligned easy.

I bought this one but had to make one of the teeth narrower, easy with a file.

Screenshot_20230119-133017.png
 
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Thanks. I’m sure the gauges have an issue with that module mentioned in another thread as both the fuel and temp don’t read. Right now I’m interested in gettin the leak stopped so it can be driven. The local parts store doesn’t have just the seal.

I contacted the sellers online of the senders and they said there are 3/8” size lines and 5/16”? Is that true? I would assume they would’ve made one sander for all of these darts in 1968.
 
You can get this on Amazon by Saturday. I would use my original lock ring for sure with the gasket.
Spectra Fuel Tank Lock Ring LO06
https://www.amazon.com/dp/B001QUTGX0?tag=fabo03-20

Don't toss or replace any parts (sending unit) until your sure they are no good. Mymopar.com will have most of your answers for original equipped vehicles. The search engine here will have hundreds of thousands answers for you. Show us some pictures and give us more info of what what you got. The group will work you through almost anything. Doesn't sound like it's too stock of a vehicle anymore.
 
1968 Dart 270 said:
Thanks. I’m sure the gauges have an issue with that module mentioned in another thread as both the fuel and temp don’t read. Right now I’m interested in gettin the leak stopped so it can be driven. The local parts store doesn’t have just the seal.

I contacted the sellers online of the senders and they said there are 3/8” size lines and 5/16”? Is that true? I would assume they would’ve made one sander for all of these darts in 1968.
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Factory is 5/16. 3/8 is an aftermarket option for high horsepower applications.
 
Bodyperson said:
Factory is 5/16. 3/8 is an aftermarket option for high horsepower applications.
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Thanks! Appreciate it. This is a great site. The seller was also telling me some have a fuel return line. I’m assuming that’s also an aftermarket thing?
 
1968 Dart 270 said:
The seller was also telling me some have a fuel return line. I’m assuming that’s also an aftermarket thing
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Fuel return can be stock on later years for smog stuff.

Spend the extra 6.00 and buy 2 lock rings and gaskets.

On my dart I had to double up in the gasket to seal it.


These videos are corny but very clear.




Product Review: A100 Fuel Sender For 67 Dart
 
I never got either one of my cars to stop seeping, so being an airplane guy, and along with the gasket, I Pro sealed mine, it's a 2 part fuel tank sealer. Used on seams or you fill in the blank. The part can be separated with a heat gun if necessary. Don't expect to ever have to go in there again in my lifetime.
Unless that car has fuel injection, it should not have a fuel return line?
 
Scamp Rhonda said:
You can get this on Amazon by Saturday. I would use my original lock ring for sure with the gasket.
Spectra Fuel Tank Lock Ring LO06
https://www.amazon.com/dp/B001QUTGX0?tag=fabo03-20

Don't toss or replace any parts (sending unit) until your sure they are no good. Mymopar.com will have most of your answers for original equipped vehicles. The search engine here will have hundreds of thousands answers for you. Show us some pictures and give us more info of what what you got. The group will work you through almost anything. Doesn't sound like it's too stock of a vehicle anymore.
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Thanks Rhonda,asides from the engine and transmission (727) everything else seems to be original. The car was originally a 273 v8 car and has fhe V8 badges on the front fenders. Interior is stock. Even all the factory air components are hooked up. Not sure why the engine was changed.like I said it’s hard to find one of these that hasn’t been messed with or hopped up. I’d be just as happy with a 318 or 273. Tomorrow I’m off work and will have time to get under it and check things out. I appreciate everyone’s help here.
 
CRUZE 418 said:
I never got either one of my cars to stop seeping, so being an airplane guy, and along with the gasket, I Pro sealed mine, it's a 2 part fuel tank sealer. Used on seams or you fill in the blank. The part can be separated with a heat gun if necessary. Don't expect to ever have to go in there again in my lifetime.
Unless that car has fuel injection, it should not have a fuel return line?
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That’s what I thought too. The sender with the return line must be for people modifiying their cars with fuel injection and electric fuel pump
 
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