| right. with the antenna mast out, there should be a metal thing you can unscrew from the car. a new one should have come with your new antenna. i cant remember if its 12 or 13mm. that should be out when you put the new antenna in. and then when you get the new antenna to go in, you can screw that thing on. that part that is too big is what gets caught on the metal piece you screw in, to keep it from extending all the way out... does that make sense? | 
