Yes, that was the return line I mentioned in the reply to your first thread; hence the suggestion to get some 5/16 ID fuel line in case that 26 year old pipe down below was rusty.

Like was mentioned, you're supposed to undo the connection between the thermoplastic line and the steel line above the axle, but usually it falls to pieces under the twist of the crossed line wrenches. It is the steel end that falls apart, but mostly folks just replace all the way back to the barb on the sender assembly.

One one of mine, I left the plastic hose intact, using a cut-off end from a tranny cooler pipe to adapt it to a rubber splice added to the steel return line. The evils of rust.

Did you ever compare with the tank full? I know I'd rather do that job with it near to empty.
--
Art Benstein near Baltimore