Im trying to replace the door glass on a 55 f100 but how do i remove it from the track inside the door?

 

Roll down the widow. Look through the big hole in the door and find the two rollers under the window on the bar. These are held in place by a C spring.Pull the spring half way out and pull the rollers free. Now your window is free and you can sink it down and out through the hole

 

Just a thought, while your doing this you might as well take out the window mech and service them, you'll be glade you did, I did mine and they work like new. Bob