Gas Cap Gasket

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Geoff, I thought you bought a sheet of the same stuff I did.
Chris, I didn't buy any material other than what I had on hand. We must have been mistaking or confusing each other somewhere along the line.
The "fish pond" material has started to deform, so it's starting to break down. I'm in no rush yet to change it, so I'll likely get the good stuff in future.
 

PeteG41

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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.

This is the one I ordered from NPD. Fit great on my 73. Absurd that it cost $12 to ship a $3 gasket, so I grabbed a couple other things to make it worth it.
 
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This is the one I ordered from NPD. Fit great on my 73. Absurd that it cost $12 to ship a $3 gasket, so I grabbed a couple other things to make it worth it.
It would fit the 71-73 with the twist on cap, but not to 71 pop open type.
 
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If you have the old one, I'd go with the same thickness. My flip-cap is repop so it doesn't have a gasket, although I'd convert if I could find the parts. I see there is a pattern of tapped holes to accept the retainer plate.
Yes, the old gasket is a good 1/16th thick. It needs at least that. The rubber I have is now not what I'm planning to use in future, it is probably .080" thick.
As for the repops, don't they have a small twist on cap under the "door", so just for looks?
 
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The stuff I linked above is 1/16" thick. Your original gasket is closer to 5/64. I felt 1/8" would be way too thick. 2 years in mine still looks fantastic and I've never smelled gas once I installed it. I can also see a noticeable ring on the gasket now which shows me it's got full seal all the way around.
 
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1971 Mustang Mach 1, M code, 4 speed.
If you got some really deep deep pockets, perkinsrestorations is selling an NOS Autolite gas cap #D1ZZ-9030-A. Yep for $950 you can own it. Currently on ebay.
Nothing but a rip off imo. I paid 10 bucks for mine with very little pitting and in vgc for the age. Good enough for the girls I go with.
 
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