Fixing a Sliding Screen Door
Clean away any dirt and buildup of dust that has gathered. It is easy to overlook screen doors because they have have curtains obstructing them, but over time, dust and dirt can build in the groove to monumental proportions. Remove this collection of dirt and dust with a handheld vacuum.
Lubricate the groove with WD-40 once it is clean. Even after vacuuming the dirt away, the screen door may still not slide properly. Lubricating with WD-40 or any kind of oil will facilitate easy sliding of the doors.
Check the rollers on the screen door. Sometimes these rollers can get bent out of shape or worn down. If the bend is minor, it can often be set back in shape with a light hammering. A major bend in the roller may require replacement.
Observe the track over the threshold. This track is even more likely to become bent than the rollers. The best way to straight out the track on a screen door is to place a thin piece of wood in the track and step on it while hammering the track against the wood.
Check to make sure the gap above and below the screen door is even. If it appears to be uneven, it can be easily adjusted. Locate the adjusting screw and if that side is higher than the other, turn the screw counterclockwise. If the side with the screw is too low, raise the door and turn the screw clockwise.