how do I unplug gas tank vent on my 1957 chevy 210?
The vent is probably a hose. I would replace the hose which attaches to the tank near the filler neck. Check any metal tubes for rust or other obstruction.
My neighbor had one of these, found out the cap would not vent as it should, replaced it and the problem went away. There was no vent in the top of the tank, he didn't know if the tank had been replaced or not, everything had been cleaned.
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