Pawnee Fuel Tank Question

Hello folks, did a little searching on past posts related to Pawnee tanks and came up empty handed, so here goes: ours is a C model with the bladder/liner equipped fiberglass fuselage tank. It's developed a leak at the bottom that I'm digging into. Discovered a poorly done previous repair that attempted to secure what the manual describes as a vent tube adjacent to the outflow shutoff valve. Except it's not the tank's primary vent, but appears instead to be a drain for fuel that might accumulate between bladder and tank in case of a leak. It's about a half inch aluminum tube that further mates to a tube out the bottom of the fuselage. Anyhow, it was glassed in place at the tank bottom and the repair has delaminated and loosened. Before further surgery, I want to verify that's its function. We removed the oval access panel on the top of the tank and sure enough, the tube does not penetrate into the bladder/liner. If I could post a pic here I would, but hopefully someone will know.

I've looked through the POH and service manuals; they only show one vent. The tank's primary vent line takes air from the sight gauge opening at the top and exits via a smaller tube out the top front of the tank, through an exit tube at the fuselage bottom. Thanks in advance.

Larry Ruggiero
Carolina Soaring Assoc
Spartanburg SC