Gas Cap Gasket

[JJHStang]

I have looked on line but haven’t found a gas cap replacement for my 71 Mach 1.
It is the flip open type attached pics.
Any ideas?

 

[Stanglover]

There isn't one as far as I know. I made my own from a piece of fish pond rubber after it was "gas tested" for a few days. Not all rubber is gas proof, make sure what you buy is.

 

[Don C]

Not easy to find gas and alcohol resistant gasket material. I've resorted to going through the gas caps at the parts store until I find one with the right size gasket and then buy the complete gas cap just for the gasket.

 

[JJHStang]

Thanks for the replies. I will have to think about making. Don’t want to buy a new gas cap at around $160.

 

[basstrix]

Buna-N, aka Nitrile, is what is typically chosen for gasoline compatibility. It gets an A rating for both gasoline and ethanol. Here's a link to a comprehensive

compatibility chart

You can get the Buna-N at McMaster, but I'm sure it's also available on ebay and amazon....I'd be weary of getting the correct material from amazon, but McMaster is a sure thing....a little more $$, perhaps, but they are an engineering materials/parts supplier and sell good stuff.

Buna-N

 

[Big Red Mach 1]

This is what Stanglover and I both used. Worked great on my end. https://www.amazon.com/gp/product/B07B41RW16/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 One 6x6 piece will make 4 gaskets.

 

[machattack]

Hi Big Red, stanglover,
Amazons piece looks to be more than needed? Could I buy a gasket from anybody?
Thanks
Rod

 

[Stanglover]

Hi Big Red, stanglover,
Amazons piece looks to be more than needed? Could I buy a gasket from anybody?
Thanks
Rod

That may be your only option to buy more than you need. Or check out the Nitrile material basstrix mentions. These gas caps were only used for 71 and some early 72's.

 

[basstrix]

This is what Stanglover and I both used. Worked great on my end. https://www.amazon.com/gp/product/B07B41RW16/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 One 6x6 piece will make 4 gaskets.

Viton, aka FKM has very good compatibility with gasoline but not as good as buna-N on methanol. For 10% methanol, should not be an issue to use viton.

 

[Bobby]

NPD has a replacement gasket as well as Amazon. I tried to replace the gasket on my 72 but could not figure out how to disassemble the cap to replace the gasket. Please post directions and pics if you know.

https://www.npdlink.com/product/gasket-fuel-cap/106665/202850

 

[Stanglover]

NPD has a replacement gasket as well as Amazon. I tried to replace the gasket on my 72 but could not figure out how to disassemble the cap to replace the gasket. Please post directions and pics if you know.

https://www.npdlink.com/product/gasket-fuel-cap/106665/202850

Yeah I bought one of those, but was too small for the flip open cap. They are for the twist on caps.

 

[Bobby]

Yeah I bought one of those, but was too small for the flip open cap. They are for the twist on caps.

the one I bought was not for the twist on cap. It was for the NASCAR hinged cap. I just could not figure out how to remove the old gasket to install the new. I ended up with a twist on cap since short of destroying the original cap, I was not going to be able to replace the gasket.

 

[Stanglover]

the one I bought was not for the twist on cap. It was for the NASCAR hinged cap. I just could not figure out how to remove the old gasket to install the new. I ended up with a twist on cap since short of destroying the original cap, I was not going to be able to replace the gasket.

Interesting. Perhaps NPD have added to their catalog. When I was searching for one, the only one they had was for the twist on cap.
It's several years ago now, but if I recall, I was able to cut the old rubber out where the two metal plates are fixed and punched a hole in my rubber piece and stretched it over and between the plates. It may not have been pretty, but it's worked fine since about 2012 when I acquired the near perfect flip open cap for 10 bucks.
Actually, I just took a couple of pics of mine and low and behold, it looks like I'll need to replace the rubber soon too.

 

[Bobby]

Interesting. Perhaps NPD have added to their catalog. When I was searching for one, the only one they had was for the twist on cap.
It's several years ago now, but if I recall, I was able to cut the old rubber out where the two metal plates are fixed and punched a hole in my rubber piece and stretched it over and between the plates. It may not have been pretty, but it's worked fine since about 2012 when I acquired the near perfect flip open cap for 10 bucks.
Actually, I just took a couple of pics of mine and low and behold, it looks like I'll need to replace the rubber soon too.

Looks bad.... I knew mine needed replacing when I would go in the garage in the mornings and I could smell gas.

 

[Stanglover]

Looks bad.... I knew mine needed replacing when I would go in the garage in the mornings and I could smell gas.

Mine is not leaking gas smell, but I did notice it is starting to crack, so it'll get a new one at some point. I still have some of the same "fish pond" material, but I may break down and buy a piece of Viton...... or Nitrile which ever is cheaper. The car will never see more than 10% ethanol anyway.

 

[JJHStang]

The one sold by NPD shows compatible for 67 - 73 Cougar but not Mustang. Another company sells the same thing but shipping is approximately $10 to $13 for a $3 to $4 item.
Have tried to get them to send me dimensions or confirm the fit on a 71 Mach 1 flip type gas cap.
I have no idea of material cost to make my own except the $25 from Amazon that Basstrix posted link for. I guess if you have to pay $25 plus tax and maybe shipping then $17 for part, tax and shipping is not bad.

 

[JJHStang]

The one sold by NPD shows compatible for 67 - 73 Cougar but not Mustang. Another company sells the same thing but shipping is approximately $10 to $13 for a $3 to $4 item.
Have tried to get them to send me dimensions or confirm the fit on a 71 Mach 1 flip type gas cap.
I have no idea of material cost to make my own except the $25 from Amazon that Basstrix and others posted link for. I guess if you have to pay $25 plus tax and maybe shipping then $17 for part, tax and shipping is not bad.

 

[basstrix]

The one sold by NPD shows compatible for 67 - 73 Cougar but not Mustang. Another company sells the same thing but shipping is approximately $10 to $13 for a $3 to $4 item.
Have tried to get them to send me dimensions or confirm the fit on a 71 Mach 1 flip type gas cap.
I have no idea of material cost to make my own except the $25 from Amazon that Basstrix posted link for. I guess if you have to pay $25 plus tax and maybe shipping then $17 for part, tax and shipping is not bad.

My link was to McMaster Carr and a bit cheaper than Amazon.

The 1/8" thick is about $12 + shipping. https://www.mcmaster.com/8635K164/

The 1/16" thick is about $7 + shipping. https://www.mcmaster.com/8635K162/

Here's a quick search on ebay....may be a little cheaper from ebay: https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313&_nkw=buna-n+sheet&_sacat=0

 

[JJHStang]

How thick do you suggest?

 

[Big Red Mach 1]

Mine is not leaking gas smell, but I did notice it is starting to crack, so it'll get a new one at some point. I still have some of the same "fish pond" material, but I may break down and buy a piece of Viton...... or Nitrile which ever is cheaper. The car will never see more than 10% ethanol anyway.

Geoff, I thought you bought a sheet of the same stuff I did.