leaking filler neck

[N180SD]

We recently purchased a Decathlon project. While getting it ready for recovering I discovered a leak around the fuel tank filler neck. Does anyone know how the steel neck is attached to the aluminum tank?

It appears to be brazed, but I'm not sure. Any help would be appreciated.

thanks

 

[jerrymjr]

Old ones were brazed, yes.

Newer ones have a welded flange that is machined and the neck is screwed down.

 

[N180SD]

Thanks for the reply. I appreciate the info.