removing/installing lock cyl's
 

i need to change the lock cylinders on my 66. the key for them was lost by the kid i bought it off of. i noticed that the replacement sets that they seel usually match the ign and tnk keys so i tried the ign key to open the tnk, didn't work, oh well. point is i need to replace the ones i have, buying new cyl's in a few weeks, but i have no clue how to remove the cylinder from the doors. any help is greatly appreciated. (p.s. i have the ign and tnk cyls done)