Plastic Fuel Line Fittings

[nanook]

Carbon Cub fuel fitting is leaking when cold (Alaska)... Are these fittings sealed/glued with something when assembled? They don't feel like a normal plastic 'B' nut when you put a wrench on them. Do you have to heat them to get them to release?

[Pete D]

All of the plastic to plastic connections of the fuel system have a dab of superglue applied after assembly to prevent them from working loose.

[40m]

Interesting question, you and I can't be the only cold climate Carbon or S2 cubs. When the temp drops to 10 degrees F mine leaks at the fittings in particular at the fuel valve. I suspect dissimilar materials play a role. I was able to gently tighten several which helped but did not eliminate the leakage. I would be interested if a sealant might help and which would be best.

Carbon Cub fuel fitting is leaking when cold (Alaska)... Are these fittings sealed/glued with something when assembled? They don't feel like a normal plastic 'B' nut when you put a wrench on them. Do you have to heat them to get them to release?

[nanook]

All of the plastic to plastic connections of the fuel system have a dab of superglue applied after assembly to prevent them from working loose.

Okay thanks Pete D. For my next question is: what is the best way to release the dab of Superglue, so I can see if this fitting is cross-threaded?

[nanook]

Interesting question, you and I can't be the only cold climate Carbon or S2 cubs. When the temp drops to 10 degrees F mine leaks at the fittings in particular at the fuel valve. I suspect dissimilar materials play a role. I was able to gently tighten several which helped but did not eliminate the leakage. I would be interested if a sealant might help and which would be best.

I was wondering if this was going to bring something out of the woodpile.
I'm looking at plastic fuel lines mated up to Aluminum fittings/lines and wondering the same as you.
This problem arose at -20F. I'm trying to eliminate the possibility of a 'B' nut being cross-threaded during assembly.
My next guess would be the alum/nylon fittings shrinking at different rates/amounts.

[40m]

I think your next guess is the right one.

I was wondering if this was going to bring something out of the woodpile.
I'm looking at plastic fuel lines mated up to Aluminum fittings/lines and wondering the same as you.
This problem arose at -20F. I'm trying to eliminate the possibility of a 'B' nut being cross-threaded during assembly.
My next guess would be the alum/nylon fittings shrinking at different rates/amounts.

[nanook]

I think your next guess is the right one.

The 'B' nut looks crooked when you look at the threads showing. This is looking through an insp. hole with a mirror and flashlight.