Just cut the old grommet off, if it was like mine you shouldn't have to cut all the way threw since it is old and will break away. Then after you reinstall the tank use some KY jelly, you know the stuff from the drug store, and lube up the grommet and the filler neck. After that it should go on real easy, the KY is water based so it will rinse away real easy with water after you get it done. Also you can have some fun with the KY, after I bought mine I came home and showed it to the wife just to mess with her. She kept asking me what I thought I was going to use that for.
