SonexBuilders.net

Greetings,

I noticed today that the flat seal inside my fuel cap seems to have swelled, and the diameter has grown to larger than the inner diameter of the cap. There's a good chance it's not even sealing anymore. I had a spare and changed it for now, but I'd like to source some replacement seals. Sonex appears to sell the cap, but there's no mention of the seal separately. https://www.sonexaircraft.com/eshop/car ... t_id=16929

I supposed I can measure and try to find a seal, but I figured I'd ask here first in case someone has already found a solution.

Thanks,
Rusty

Buy the one Pete Anson sells. It seals much better than the stock sonex one and uses a standard o ring if it ever needs to be replaced.

Thanks. I emailed Peter to ask about that after I saw your message. His cap is radically different, though I can see how it could work. I wasn't sure if all Sonex always used the same caps, which was why I left a link to the one I have. I would certainly love to improve the cap, particularly since it's inside the cockpit with me.

Rusty

There are two different style of gas caps for the Sonex A models. The original design was for a internal expanding stopper type seal. This is what Peter's improved design is to replace. The newer tanks have a screw top cap. I'm not sure if you can use Peter's cap on the newer tanks... but it is smooth on the inside.

Gregg Short
Sonex 715

Peter replied that the new type cap can, and has been used on the new tanks, but the ID of the neck is a little smaller on the new tank. He can make both sizes, but he asked me to measure the ID of my tank to make sure the size will be right. I will probably order one, and also get the 90 degree check valve fitting for the vent tube on top of the tank. I think both of those items will make me feel better about what would happen if I ever end up upside down in a corn or soybean field.