I am dropping the fuel tank on our newly acquired '64 Buick Electra- needs to be flushed and sealed. The only thing holding the tank in is the filler neck. This is the old metal tube sleeved through a metal press ring. The repair manual only states to pull the filler neck free of the tank but no matter how I twist and pull on the tank and the neck, it refuses to budge. Is there some technique that I am missing on getting the filler neck out of the tank port? Gary '64 Buick Electra '93 GMC Sierra HD '02 Harley Davidson Electra Glide Ultra Classic