Replacing gasket on pop open gas cap

[JJHStang]

I have prior posts on gasket replacement for my 71 Mach 1 and thanks everyone for the help.
I have found some neoprene rubber to make my own. The original thickness is between 1/16” and 1/8” .
The best I can measure which makes it hard to find. The rubber I found is 1/8” hoping it is not to thick.
I will find out.
My question is has anyone found the best way to get the center hole of the gasket to fit under the center of the gas cap?
Just looking without taking off the old gasket it must fit under the center of the gas cap.
If not explaining myself good I have attached a picture.j

 

[Stanglover]

You might find that too thick to be honest, but worth a try. The top "washer" if you like is fixed as you know. Cut out the old one and clean the gap between the top and bottom. Try to get an idea of the inner diameter between the base and washer (for want of a better term) and cut the rubber just a little larger to allow for any "squeeze" there will be with that thickness rubber. Use dish soap or similar as a lubricant and gradually work the rubber around.
To be honest, I'm not sure neoprene will last long, but I could be wrong.
Good luck,

 

[Big Red Mach 1]

1/16" works better than 1/8" and most importantly - still seals. In order to remove, just tug on the old one. It will slip out from under the "cone" in the middle. Then just work it around. Do the opposite to install. There is some stretch to the material and it won't rip unless you pull WAY harder than needed. If you run into trouble with the 1/8" I might have enough 1/16" material to send you one. I already sent one of these to another member on here.

 

[Big Red Mach 1]

I sent one to machattack a while back. I do have enough to send out another one if needed.

 

[tony-muscle]

https://www.amazon.com/s?k=hillman+neoprene+washer&crid=1SLSKVK8BTHEV&sprefix=hillman+neoprene+washer%2Caps%2C89&ref=nb_sb_noss_2

Follow this link for many neoprene "washer" sizes from Hillman in Amazon.

Select Neoprene or other as material, then select OD, ID and you will get many options.

 

[machattack]

I sent one to machattack a while back. I do have enough to send out another one if needed.

It worked perfectly! Many thanks for your help on that!
Big Red, Can I buy a spare? Please.

 

[Stanglover]

https://www.amazon.com/s?k=hillman+neoprene+washer&crid=1SLSKVK8BTHEV&sprefix=hillman+neoprene+washer%2Caps%2C89&ref=nb_sb_noss_2

Follow this link for many neoprene "washer" sizes from Hillman in Amazon.

Select Neoprene or other as material, then select OD, ID and you will get many options.

Interesting find there.

 

[Big Red Mach 1]

2 5/8 outer, 3/4 inner would be winner, winner chiken dinner.

 

[Stanglover]

2 5/8 outer, 3/4 inner would be winner, winner chicken dinner.

.............. but are they gas proof???

 

[tony-muscle]

.............. but are they gas proof???

The typical materials used for gasoline are NBR or Nitrile Rubber or Buna-N, and Viton. Neoprene in theory has moderate resistance to gasoline and may work in this application where it is not constantly submerged. Further, the fuel system will still work if it fails which reduces risks. However, since there are many grades of each of these rubbers you have to do your homework.