I'm doing a conversion that requires a return line for an electric fuel pump system.

The fuel breather line that normally goes to the carbon canister is perfect to use as a return line but before it goes into the tank in goes to a small tank hidden near the fuel filler neck in the side of the ute tray. I would like to just bypass this and hook it straight to the top of the tank but the filler neck also has a plastic tube on the side of it that appears to also go into the top of this small tank. If I disconnect the lines will I have problems with the tank breathing?

Thanks,
Daniel