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+...llman+neoprene+washer,aps,89&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+...llman+neoprene+washer,aps,89&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.

 

[JJHStang]

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.

I decided to make my own. I found 3/32” thick neoprene 12” x 12” sheet on Amazon for less than $5. My existing gasket measured 3/32” using a multimeter. Found that the diameter of a can of soup is just slightly larger than 2.5”. I marked it on the sheet of rubber and cut it using a exacto knife. Then found a socket that was an inch diameter used it for measuring and cutting the center hole. Not perfect but it seals very well. I stretched the rubber around the center and with a thin flathead screwdriver push under the lip.
I have attached a few pictures and below is the link to Amazon.

https://www.amazon.com/Comm-Grade-N...6&sprefix=3/32+neoprene+rubber,aps,175&sr=8-4

 

[Big Red Mach 1]

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

Mine is.

 

[JJHStang]

Mine is.

I decided to make my own. I found 3/32” thick neoprene 12” x 12” sheet on Amazon for less than $5. My existing gasket measured 3/32” using a multimeter. Found that the diameter of a can of soup is just slightly larger than 2.5”. I marked it on the sheet of rubber and cut it using a exacto knife. Then found a socket that was an inch diameter used it for measuring and cutting the center hole. Not perfect but it seals very well. I stretched the rubber around the center and with a thin flathead screwdriver push under the lip.
I have attached a few pictures and below is the link to Amazon.

https://www.amazon.com/Comm-Grade-N...6&sprefix=3/32+neoprene+rubber,aps,175&sr=8-4

Mine is.

What I read. Neoprene is popular due to its unique combination of properties and has led to its use in thousands of applications in diverse environments. Neoprene is a polymer that provides moderate oil & gasoline resistance, very good resistance to ozone & sunlight, excellent adhesion to fabric & metals, good resistance to abrasion & flex cracking and very good resistance to alkalis & acids

 

[Big Red Mach 1]

Here's the link to the Viton sheet I purchased. More expensive at $25 for a 6"x6" sheet, but you can get 4 gaskets out of a sheet. https://www.amazon.com/gp/product/B07B41RW16/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1

 

[Stanglover]

What I read. Neoprene is popular due to its unique combination of properties and has led to its use in thousands of applications in diverse environments. Neoprene is a polymer that provides moderate oil & gasoline resistance, very good resistance to ozone & sunlight, excellent adhesion to fabric & metals, good resistance to abrasion & flex cracking and very good resistance to alkalis & acids

......... and why they make diving suits ( dry and wet suits) out of it.

 

[Ronk]

Following this thread last week I purchased some black neoprene sheet (from Amazon) and cut out a few gaskets. Mine fit great.

I offer the others I have to the group as Xmas presents if anyone wants them. I mean you get 10 gaskets out of a $10.00 sheet so a buck each is a cheap Xmas present to fellow 71-73 folks.

Seasons greeting Ron
Merritt Island FL.

 

[Ronk]

In case it wasn’t clear in my post, I will send one FREE just send me you address and I will put it in an envelope to you.
Again, Merry Xmas from Florida.
Ron

 

[JJHStang]

In case it wasn’t clear in my post, I will send one FREE just send me you address and I will put it in an envelope to you.
Again, Merry Xmas from Florida.
Ron

How did you measure and cut yours?

 

[JJHStang]

What did you use to measure and cut?

 

[Ronk]

I used the old gasket to outline the 2 circles onto the sheet and hand cut with scissors the outer circle and a large hole punch for the center.