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- - Gas Cap (https://67-72chevytrucks.com/vboard/showthread.php?t=761150)

Gasket is cracking What is causing this? This is the second cap in less than a year Attachment 17718500

Yes the gasket . This cap is only 4 months old

Are those supposed to be good quality caps you're buying? Mine's at least 5yrs old and the gasket is fine. Doesn't fit particularly tight but doesn't slop gas out or smell. Does the surface that bears on the gasket look/feel smooth? I run both ethanol and non-ethanol in mine. Maybe a little dab of lubricant would keep it from doing that.

My gas cap on the 67 C10 did the same thing in no time as well.

They were both stant from Napa.

Maker probably cheaped out on materials. Acquire a piece of Nitrile sheet and cut your own ring. 3/16 thick ought to do it.

Part of it is the cheaper materials used in today's replacement parts.Part of it is the 10% ethenol in the fuel.

Quote:

Originally Posted by RustyBucket (Post 8231744)

Interesting, what type of lubricant would one use that today's fuel would not dissolve in a hurry?

I like the idea of cutting a piece of nitrile and putting on there. I have one on my truck, Stant, from Napa and it is cracked but not yet broken up yet. Over a 1 year old now.

Updated, something to definitely to consider, Viton is the product to use in this application.

Reasoning Here: https://www.customadvanced.com/chemi...ine&rubber=NBR

So I just checked my cap and that gasket comes right off there and is cut in a circle. This one is going to be an easy permanent fix.

I love the internet for one thing, information collection:

https://www.discountrubberdirect.com...-ring-gaskets/

Quote:

Originally Posted by RustyBucket (Post 8231744)

If you have an old inner tube lying around, try cutting a gasket from it. I did it years ago and thought it would fail within months, but it's still not showing any signs of failure. It also seals tighter. Worth a shot.

Thanks for all the great info.