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1/20/2020 11:28 PM  #1


Gas tank leak

My '66 sometimes smells of gas while driving. It's coming from the fill tube area at the tank, but I can't find a leak. The tank is in good shape with no cracks or damage. Same with the rubber connecting hose from fill tube to tank. I have 4 clamps on the hose and sealant at the tank where
the short neck connects on the top rear of the tank. I will replace the rubber fill hose even though I don't see any damage.
I recently overfilled the tank up to where I could see the gas in the filler neck. The next day I checked it and gas had partially soaked the foam pad i made to cover the tank.
I'm going to replace the hose to the tank even though it looks fine.  Am I missing something?

 

1/21/2020 8:36 AM  #2


Re: Gas tank leak

Maybe check more closely around where the welded tank seam is for pin holes

 

1/21/2020 9:10 AM  #3


Re: Gas tank leak

It looks good but I put a bead of JB around it. I'll try pressurizing next.

     Thread Starter
 

1/21/2020 12:20 PM  #4


Re: Gas tank leak

If you haven't found it visually, then I would proceed with some air pressure. That and soapy water should have your tank blowing bubbles quickly.


John  -- 67 Mustang Coupe 390 5 speed
 

1/21/2020 2:40 PM  #5


Re: Gas tank leak

Fuel aromas were common in our cars from the beginning.  Somehow the vented fumes from the gas cap worked their way back into the compartment.  Rather disconcerting, but not dangerous.  That being said, go right ahead and do whatever you must to get rid of those pesky things!


Original owner - 351w,T-5, 4whl disks, power R&P
 

1/21/2020 3:37 PM  #6


Re: Gas tank leak

Is this a stock style tank?

Is the fuel level in the interior?...like a Tanks Inc or Holley

If you replace the filler hose, I suggest to replace the tail panel seal too.

Last edited by Nos681 (1/21/2020 3:42 PM)

 

1/21/2020 3:40 PM  #7


Re: Gas tank leak

Stock replacement tank. Think it was Spectra premium.

     Thread Starter
 

1/21/2020 3:47 PM  #8


Re: Gas tank leak

When you replaced tank, did you use a new filler hose?

 

1/21/2020 3:52 PM  #9


Re: Gas tank leak

Might want to check trunk seal as well.
Especially along edge adjacent to tail panel.
Seal can be in good condition.
if there is a gap, fumes could be drawn in as well.

Does this occur only while driving?

 

1/21/2020 5:08 PM  #10


Re: Gas tank leak

I had the the same issue with mine. I couldn't see where it was coming from but the leak got progressively worse. With a full tank I was getting a considerable amount of gas in the trunk. I decided to replace the tank. When I put a wrench on the drain plug it crumbled and fell out. I recommend you replace the tank.


"anyone that stops learning is old, whether at twenty or eighty"Henry Ford
 

1/21/2020 5:51 PM  #11


Re: Gas tank leak

I looked closer and the top of the tank is rustier than I thought. I will look for any pinholes when I get time to pressurize the tank. Will post back when I find the problem.

     Thread Starter
 

1/23/2020 9:17 AM  #12


Re: Gas tank leak

whlnut wrote:

I looked closer and the top of the tank is rustier than I thought. I will look for any pinholes when I get time to pressurize the tank. Will post back when I find the problem.

 
If it's rusted on the top the bottom is no doubt ready to go.


"anyone that stops learning is old, whether at twenty or eighty"Henry Ford
 

1/23/2020 10:25 AM  #13


Re: Gas tank leak

I would not attempt to pressurize a leaking gas tank. It is very dangerous.  Just buy a new tank before all that rust in there clogs up your carb.


Money you enjoy wasting is NOT wasted money... unless your wife finds out.
 

1/23/2020 11:01 AM  #14


Re: Gas tank leak

Understood. To clarify- the rust is only on the top of the tank from the trunk mat and pad that I put in holding moisture. I will replace the tank.
Thanks for the replies. Ed

     Thread Starter
 

Board footera


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