How do you replace fuel tank vent ?

Most likely this is not a vent valve problem, because the fuel has to go through the carbon canister to get through the vent valve. Toyotas have had a lot of problems with their canister pellets melting and the the canister becomes blocked and will not let any air out as you fill that tank. I would look in that direction. The canister and vent are all one assembly and are not cheap. If the vent valve was defective, you would have a check engine light on and a P0446 code flagged as well.