When a bifold door opens or closes poorly, adjusting it is usually easy. On the “hinge” side of the door, a pin at the door’s bottom corner typically rests in a floor bracket, and a spring-mounted pin at the top corner engages a sliding bracket that locks into the track. If the folding door’s hardware is missing or damaged, you’ll need to replace it. You can buy folding door hardware online.
When the door drags or pops out of its track, it usually means that one of these two pivots has moved.
1 Open the door, making sure its upper guide roller is in the track.
2 Check the bottom corner pivot pin. Be sure it’s properly engaged in the floor bracket and adjusted to allow about 1/16-inch clearance from the jamb at the bottom corner of the door when the door is closed. To adjust its position, lift the door upward (the top pin is spring-loaded to allow this).
3 Check the top pivot pin. A very common occurrence is that the sliding bracket has loosened and has slid out of position. Align it so the hinge side of the door is plumb, with about 1/16-inch clearance from the jamb when closed, and tighten the sliding bracket into the track.
4 Adjust the hinge side of the door up or down by turning the bottom pin, which is threaded like a bolt. With some types, you must first lift it out of the floor bracket.
When the door is loose and wobbly, one of the pivot pins has probably worn away at its seat in the door (a hole) and come loose. The fix is to remove the pin, fill the hole with a dowel plug, and then re-drill a hole near the same location.
1 Lift the door up and out at the bottom to remove it.
2 Pull the loose pivot pin out of its hole.
3 Enlarge the hole with a drill or hole saw so that it’s perfectly round and will receive a wooden dowel plug.
4 Spread glue onto the dowel plug, and tap it into the hole. Wipe away any excess glue.
5 Cut off the dowel, making sure it is flush with the door.
6 Drill a new hole to receive the pivot pin. If the pin is damaged, replace it.