Fuel leakage when tank is full
06-20-2019, 11:29 AM
#1
Intermediate
Thread Starter
Fuel leakage when tank is full
Hello, I have a 1965 and when I fill the fuel tank I usually don't fill it all the way into the neck of the tank. Yesterday I did as I had a few miles to drive and thought why not. I would be using at least a couple of gallons. As I did so, I saw a few bubbles appear inside the tank then some fuel started dribbling out near the rear valance. This is a first. I had noticed that when I usually have a relatively full tank I smell fuel in my garage. I'm wondering if there is a vent or gasket seal on the top of the tank? I've never removed it and am wondering what I should look for? Your advise would be appreciated!
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59BlueSilver (06-21-2019)
06-20-2019, 03:10 PM
#2
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There is a paper gasket in the fuel cap. And there is a gasket between the tank and filler neck as well.
Last edited by Nowhere Man; 06-20-2019 at 03:11 PM.
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brianebon (06-20-2019),
JL66REDCPE (06-21-2019)
06-20-2019, 03:25 PM
#3
Team Owner
The black rubber "toilet plunger" around your gas cap has an overfill hose attached to it that drains out behind the vertical part of the rear bumper (PS IIRC)...you can prob feel the hose with your finger inside the bumper... If your cap doesn't seal well fuel can slosh up the filler neck and enter the overflow hose...
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brianebon (06-20-2019)
06-20-2019, 03:42 PM
#4
Safety Car
It can also be the sending unit where the gas line comes out the bottom of the tank. There is a rubber O-Ring sealing the unit that can go bad. Same thing happened to me; over 1/2 full & I got garage odors.
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brianebon (06-20-2019)
06-20-2019, 04:50 PM
#5
Melting Slicks
Brian
Here is some info on the fuel filler neck cork gasket and the overflow hose from the fuel filler boot. It sounds like it might be the neck to tank gasket since you filled it into the neck this time. That same thing happened to me the very first time I filled the tank on the '65. One of the many fixes I had to undertake along the way.
You might be able to peel the boot back a bit to see if there are fuel stains around the base of the neck. If it's old, that rubber boot might be a bit brittle.
Good luck tracking it down.
Dave Z
Here is some info on the fuel filler neck cork gasket and the overflow hose from the fuel filler boot. It sounds like it might be the neck to tank gasket since you filled it into the neck this time. That same thing happened to me the very first time I filled the tank on the '65. One of the many fixes I had to undertake along the way.
You might be able to peel the boot back a bit to see if there are fuel stains around the base of the neck. If it's old, that rubber boot might be a bit brittle.
Good luck tracking it down.
Dave Z
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brianebon (06-20-2019)
06-20-2019, 05:17 PM
#6
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The boot goes around the fuel fill neck. There is a nipple on the rear of that boot. Onto that nipple goes an overflow hose. On midyears, that hose is directed behind the passenger's side bumper.
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brianebon (06-20-2019)
06-20-2019, 05:48 PM
#7
Advanced
Brian
Here is some info on the fuel filler neck cork gasket and the overflow hose from the fuel filler boot. It sounds like it might be the neck to tank gasket since you filled it into the neck this time. That same thing happened to me the very first time I filled the tank on the '65. One of the many fixes I had to undertake along the way.
You might be able to peel the boot back a bit to see if there are fuel stains around the base of the neck. If it's old, that rubber boot might be a bit brittle.
Good luck tracking it down.
Dave Z
Here is some info on the fuel filler neck cork gasket and the overflow hose from the fuel filler boot. It sounds like it might be the neck to tank gasket since you filled it into the neck this time. That same thing happened to me the very first time I filled the tank on the '65. One of the many fixes I had to undertake along the way.
You might be able to peel the boot back a bit to see if there are fuel stains around the base of the neck. If it's old, that rubber boot might be a bit brittle.
Good luck tracking it down.
Dave Z
06-20-2019, 07:53 PM
#9
Race Director
If it's dribbling out of the overflow hose then it's the cap gasket that is bad. If it's running down the outside of the tank and dripping off it then it's the filler gasket. Some of us have had to take two filler gaskets and RTV them together and install to get enough gasket crush for a seal.