• If you have bought, sold or gained information from our Classifieds, please donate to 7173 Mustangs.com and give back.

    You can become a Supporting Member which comes with a decal or just click here to donate.

Gas Cap Gasket

7173Mustangs.com

Help Support 7173Mustangs.com:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Joined
Feb 7, 2020
Messages
795
Reaction score
342
Location
Arizona
My Car
73 Mach1
Anyone know where I can get a replacement gasket for the flip down fuel cap? Mine is torn. Everything I google comes up with the gasket from the housing to the car. I need the cap to the housing. I would not mind buying the smaller internal cap too. Just don't want to have to replace the entire OEM from a 71 for a repop. Thanks!!



 
Last edited by a moderator:
I had to make one for mine. The one for regular gas caps did not fit. You will need to get some rubber that is NOT damaged by gasoline. Mine was a piece of 1/16th  fish pond material and I tested some before using it.

So, you have a 71 only gas cap on your 73. Original or repo?

 
I had to make one for mine. The one for regular gas caps did not fit. You will need to get some rubber that is NOT damaged by gasoline. Mine was a piece of 1/16th  fish pond material and I tested some before using it.

So, you have a 71 only gas cap on your 73. Original or repo?
I was told by the previous owner that it's a legit 71, and not a repop. Do you know of an obvious way to tell if it's truly OEM?

 
I had to make one for mine. The one for regular gas caps did not fit. You will need to get some rubber that is NOT damaged by gasoline. Mine was a piece of 1/16th  fish pond material and I tested some before using it.

So, you have a 71 only gas cap on your 73. Original or repo?
I took a shot on the gasket found by Johnn J that may or may not work from NPD, but also bought this which definitely should if that one does not.  

https://www.amazon.com/gp/product/B07B41RW16/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

 
Last edited by a moderator:
If it is an original it will have Ford logo in casting and the regular caps have Autolite on 71 & 72 and 73 will say Motorcraft. If you zoom in on the pic the Autolite and Mororcraft marks are at the top of the cap on the steel inside part. Both of these are service caps they had the cable so you did not loose them or someone steal them.

 
I had to make one for mine. The one for regular gas caps did not fit. You will need to get some rubber that is NOT damaged by gasoline. Mine was a piece of 1/16th  fish pond material and I tested some before using it.

So, you have a 71 only gas cap on your 73. Original or repo?
I took a shot on the gasket found by Johnn J that may or may not work from NPD, but also bought this which definitely should if that one does not.  

https://www.amazon.com/gp/product/B07B41RW16/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
 That'll work. good find. I may buy some of that myself as the pond rubber I have is showing some signs of breaking down now.

 
If it is an original it will have Ford logo in casting and the regular caps have Autolite on 71 & 72 and 73 will say Motorcraft. If you zoom in on the pic the Autolite and Mororcraft marks are at the top of the cap on the steel inside part. Both of these are service caps they had the cable so you did not loose them or someone steal them.
 He has a 71 pop-open cap David.

 
I tried the The NPD gasket this week. My original was brittle and had a tear in it too.

The NPD gasket will fit on the flip cover, but not correctly, it doesn't seem to seal very well. First, it is a smaller diameter than the original,but just barely covers the end of the gas filler tube. Second, it's too thin and doesn't seal as well as it should.

You could double them up and that might be OK. Before I do that, I just picked up a large, 1/8 inch thick rubber washer from Lowes and am going to enlarge the center hole to see how that works.

 
I tried the The NPD gasket this week. My original was brittle and had a tear in it too.

The NPD gasket will fit on the flip cover, but not correctly, it doesn't seem to seal very well. First, it is a smaller diameter than the original,but just barely covers the end of the gas filler tube. Second, it's too thin and doesn't seal as well as it should.

You could double them up and that might be OK. Before I do that, I just picked up a large, 1/8 inch thick  rubber washer from Lowes and am going to enlarge the center hole to see how that works.
Thanks 71 Coop. That's what I was afraid of, it either not working or providing a poor seal. 

That's why I bought a 6"x 6" piece of this stuff as a backup. I'll bet this is what I end up using. 

https://www.amazon.com/gp/product/B07B41...UTF8&psc=1

 
I now have to retract part of my earlier comments - this morning I took a second look, and just realized the inner part of the flip-down cap is spring loaded. What I took for slack when closed with the new gasket was really the spring loaded portion of the inner cap pushing back.

The NPD gasket should seal well enough as long as the spring inside the cap is applying pressure to the gas tank neck. My apologies if my earlier comments mislead anyone.

 
I'd just make my own from that material you ordered and be done with it. These cap were only a 1 year thing,  so likely no re pops were made for it. As I mentioned before, I already did this dance.

 
Last edited by a moderator:
I should mention that I used the 1/16. The 1/8 seems like it would be too thick and may make the cap difficult to lock back in. You can see that my 16th material is making contact all the way around.
 Yes indeed, the 1/16th will be perfect. Well done.

Oh, one more thing, If you need to replace the gasket that goes under the filler neck through the tail panel, use TWO gaskets. I found the repops a bit too thin to give a good seal. I would add, that my tail panel is a repop, but the thicker one available.

 
Last edited by a moderator:
Back
Top