Steel AN Fittings on Aluminum Hardlines (Corrosion?)

[Phil]

I'm getting ready to pass my aluminum fuel line through the firewall later tonight.

The plans call for an aluminum AN fitting at the firewall and I recently swapped mine for a steel fitting. I'd like to keep as much steel on the firewall just in case...

For those of you who have done this, have you experienced any corrosion between the aluminum and steel? What type of preventative measures can I take?

This seems like a really good place for corrosion to go undetected on a mission critical item.

Common sense tells me that corrosion is guaranteed and an in-flight fire is not. So I should eliminate the steel fitting and take the known route of aluminum.

Thanks,
Phil

[terrye]

I would go steel. I would assemble the fittings with Fuellube or equivalent. If you are worried about dissimilar metals corrosion, you could take the fittings apart after say 2 years or 5 years and inspect/replace them.

Similar discussion currently taking place about oil cooler fittings. Recommendation there is also steel.