1958 CDV fuel tank leak only when 100% full

[TomJudd]

When topping off my new to me 58 Fuel leaked out  at gas station. Never any leaks less than full.Took home and parked ,couldnt access to see leak origin. Total of couple cups leaked out, then fine. Is there a vent tube on top of tank. I know the 59 s had a u shaped vent tube on forward side of tank. Note ...the tank is shiny so probably a repro.Thoughts?  Possible leak at sender unit?? Otherwise next step is put  on lift , fill to top, and observe

[dn010]

The 57 has a vent so 58 should as well. I'd check the sender to make sure it has a gasket installed and it is screwed down tightly.

[Daryl Chesterman]

Check the hose clamps on the section of hose that connects the filler spout with the gas tank—maybe they are loose, or the hose itself is defective.

Daryl Chesterman

[TomJudd]

Finally repaired. Once on lift very obvious. 1/2 OD vent tube was fossilized, loose at tank end, couldnt be tightened w clamp. I was thinking this was only a "while fueling" vent. Its the only vent !! As always appreciate input.

[Big Fins]

I have a vent like this on the '69 I just bought, so it's been carried forward in the years.