Fuel filler pipe gasket replacement


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Well-known member
Feb 5, 2024
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My Car
1972 Mustang Mach1
I found out I have a small gap in my filler pipe gasket going into my fuel tank. Time to replace it! I had hoped to be able to do without dropping the gas tank. I think that dropping it will be necessary due to some adhesive holding the filler pipe at the rear (see picture). Question - (1) how best to dissolve or remove the adhesive (2) what would be signs that replacing the gas tank and components at this time (since I will be dropping it). I think these components are all original based on condition. Thanks! First picture shows from inside the trunk of the filler tube adhesive, Second shows the old gasket and gap that exists (causing fuel leak).


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Since you have to drop the tank anyway, just replace it. Your original tank is over 50 years old and is bound to have rust and corrosion inside. A new fuel tank is not expensive. I just bought a new tank for my '72 convertible off eBay for $133 shipped. This is the tank I bought:


While you have the tank out, replace the rubber fuel supply and vapor return hoses and the associated hose clamps. Replace the rubber hose and clamps at the fuel pump inlet, too. I also recommend replacing the vapor return valve and its rubber seal (about $55 from NPD). It might also be a good idea to replace the fuel gauge sending unit. It's probably a rusty mess as well, plus the filter "sock" may have disintegrated. They don't cost much, usually less than $30.

As they say, "Buy once, cry once." Replace it all now and you'll never have to do it again for the rest of your life. The whole job will take one afternoon and cost you less than $250, and when you're finished you'll have a million dollars' worth of peace of mind.

I am about to do this entire job on my Mustang. I am waiting on parts to arrive and for my helper to have some free time. We did this exact same job on my '73 F100 Explorer Special a couple of months ago as well. Its fuel tank was a horribly rusted mess, as was the sending unit. The rubber hoses were leaking fuel, too. They weren't cracked. The fuel was literally seeping through the 51 year old rubber! I shot this photo of the inside of the tank with my cell phone camera. You can see the rust and crud, as well as the fragments of the broken fuel inlet filter "sock".

Fuel tank.jpg
Fuel tank replacement.
While there are a few brands offering tanks. I suggest the Spectra Premium F32A tank which is made in Canada and is "terne coated", which is a zinc alloy coating inside and out. This is a premium tank that will last the lifetime of the car. Best price is on RockAuto.
While at it you'll need a new sender unit. The Dorman 692232 is about the best I've found, BUT don't forget, they may need to be adjusted (calibrated).
I think we discussed this previously.
There was some sort of matting between the tank and trunk floor. It seems to be unavailable. I added some small pieces of solid rubber to act as a vibration barrier plus allow some air flow over the top of the tank. The tank vapour system will need to be restored. There is/was some material in the cap. You can replace that with a piece of ss scoring pad or similar. Also been discussed before.


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Thank you all for the good recommendations - all solid points. I visit my project car on the weekends (haha) so I'll start pulling the parts list together for this next weekend!
A tip; replace the carriage bolts, washers and nuts that hold the tank straps with galvanized. These would be 3/8" x 3 1/2 or 4" long.

The old bolts may be a bi*ch to remove, spray with a good penetrating oil a day or so ahead of time.
Anything else to help, just ask.
I have a tank I installed 20+ years ago, but never saw fuel as the project stalled.

When I restarted the project in tank pumps were available so I did that.

Shipping is expensive, but I will sell for a reasonable price.

It has the vent hat, fuel level and filler ring so it will be ready to go.

PM me if interested and I can figure out shipping/cost
Just a quick check - on the filler neck gasket there is a flared or beveled side - should this go 'up' or 'face inward' to the tank?

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