2 you may need to create more room when you attempt to remove the sliding unit from the door frame.
How to change rollers on sliding glass patio door.
Insert the new rollers in the door lining up the holes on the rollers with the holes in the bottom of the door insert the new rollers in place.
Grasp both sides of the frame and lift the door up off of its tracks.
First lift the rollers off the track by sliding a flat head screwdriver or putty knife under the roller and pushing up.
Replace the roller screws and use your phillips screwdriver to turn them clockwise until tight.
Remove the screen door if you have one.
How to replace the rollers on your patio door.
How to replace the roller assemblies in a glass sliding door i made this video because i needed to replace the slide rollers in my 10 year old glass sliding.
One unit is the door that you slide and the other unit is stationary.