A sliding door roller replacement is not a difficult task but it is time consuming indeed. To start the task, you should remove the sliding panels to get rid of the weight as it makes the task a lot easier to do.
The sliding doors consist of a track that holds the door still. It helps the door move forward and backward. The base of the door consists of rollers. Over time, these rollers wear out. To fix the door, your need to remove and replace these sliders.
The simple way to remove your sliding glass doors
On the bottom edge of the door there is a cap. Remove that cap and it will expose the screw inside. Use the right sized screwdriver and loosen the nuts. Repeat that with both the left and the right ends of the sliding doors.
Once the screws are loosened, allow the sliding door roller to slide open partially and grip it from both sides of the door with your hands. Inspect whether it can be lifted into the top track while the bottom to come out easily, if so, do it and lift the rollers off the bottom of the track to gently pull the door towards you and move the door away from the frame.
If the door is heavy for you to lift, use pry bars to pry it up from the bottom on it. Prying includes placing a piece of backer board below to prevent any damage, especially if the flooring is made of timber floorboards. Back both side with a piece of backer-board and if you still face any clearance issue, remove the set screw in each corner.
This allows the adjustment wheels to be turned and this will pull the wheels all the way up into the frame in such a way that it lowers the door down, clearing the door out in the process.
What about removing sliding fly-screens?
The sliding fly-screens can be moved out of the way, pretty much the same way as removing the glass sliding door.