Vyton o-ring not sealing in the cold

[Vlad]

I replaced stock tank drains o-rings with vyton ones. Yesterday I noticed that after fuel sampling both drains were wet and I couldn't "work" them shut. I've read somewhere in the forums that vyton isn't tolerant to lower temperatures but couldn't find the topic. Should I switch back to regular O-rings? I burn a fair amount of ethanol laden fuel.

[az_gila]

Originally Posted by Vlad

I replaced stock tank drains o-rings with vyton ones. Yesterday I noticed that after fuel sampling both drains were wet and I couldn't "work" them shut. I've read somewhere in the forums that vyton isn't tolerant to lower temperatures but couldn't find the topic. Should I switch back to regular O-rings? I burn a fair amount of ethanol laden fuel.

Are you at a temp of -15F or below?

http://www.marcorubber.com/materialguide.htm

[Raymo]

This thread?

http://www.vansairforce.com/communit...ad.php?t=69354

[simpkinsona]

Just heat the leaking sump valves with a lighter 😀

[DaleB]

Originally Posted by simpkinsona

Just heat the leaking sump valves with a lighter 😀

And as a bonus it will de-ice the wings in a hurry!

[sblack]

Originally Posted by simpkinsona

Just heat the leaking sump valves with a lighter ��

Nowhere near enough heat in a lighter. Plumber's torch is much more effective.

Notice: The owners of this forum take no responsibility for the strange sense of humor of some posters

[flyboy1963]

Surely someone will recommend just putting your lips around the leaking drain, and blow?
( caution, fuel may contain lead, a chemical known to the state of common sense to contain compounds causing stoopid ideas like this!)

[1001001]

Buna-N o-rings will have more flexibility at low temperature than viton. Viton only remains flexible down to about 5 degF. Buna-N should be good to -22degF.

To add a bit more, viton is a trade name for FKM elastomer, which happens to be the same class of material used in the space shuttle booster o-rings up to and including STS-51L (Challenger's last flight), the famous failure of which was written up to low temperature related stiffness (proximate, not root cause).

Buna-N is a type of nitrile rubber which also has good chemical resistance and lower temperature tolerance .


Both Buna-N and Viton are compatible with ethanol containing fuels.

[Bill Boyd]

Originally Posted by simpkinsona

Just heat the leaking sump valves with a lighter 😀

Hey - I was going to say that! Molotov, and all...

-Stormy

[Ironflight]

I have gone away from the Viton on my brake calipers because of exposure to cold, so yes, I think I'd try Buna-N if you want to keep something there year-around.