If your sliding glass door does not move or is falling off the track, you may be able to correct the problem by simply repairing the plastic rollers. The rollers may crack or wear down over time, especially if the tracks are dirty. Debris in the tracks grinds down the plastic rollers. As the weight of the door passes over, the debris can also dig into the track itself unless your sliding glass door has metal tracks.
Lubricate the rollers with a penetrating oil if your sliding door is stuck. Remove any debris in the track that may impede the door's movement.
Adjust the rollers if the glass door wobbles or sticks as it moves along the track. Look for the small holes in the door near the top and bottom rollers. Depending on the design of your doors, the adjustment holes may be on the front of the door or along the edge. Insert a small Phillips screwdriver into each hole and turn it counterclockwise to expand the rollers if your door is too loose. Turn the screwdriver clockwise to retract the rollers if the door sticks.
Lift the bottom of the sliding door straight up to remove the bottom set of rollers from the track. Pull the door down and away from the top track to release the top rollers. Place the door on a sturdy table or workbench so you have a clear view of the rollers.
Inspect the rollers and replace any that are broken, cracked or worn out. To remove the rollers, take out the screws above the adjustment holes. Try not to separate the door frame from the glass as you pull off the rollers.
Remove the mounting screws along the top and bottom of the doorway if the tracks show signs of damage or wear. Install replacement tracks and tighten the screws to hold the new tracks in place.
Tilt the bottom rollers toward you and set the top set of rollers in the top track when you are ready to reinstall the sliding glass door. Lower the bottom of the door until the rollers snap into place in the bottom track. Repeat Step 2 to adjust the rollers if the door does not fit in the tracks properly.