Adjusting bifold closet door hardware is a needed periodically when the doors start to operate poorly. Most of the time it only takes a few minutes to adjust the door. It is easier when you have some help to hold the door.
Adjusting the Top Pivot Pin
The first step in adjusting bifold hardware is the top pivot. There is a clip in the track that the top pivot fits into, it will be near the jamb. This clip has a set screw, ususally phillips, that holds it in place. Hopefully, the opening is square and plumb you want the margins around the door to be even.
You loosen the set screw to move the top of the door closer to the frame or father away. Does the door bind on the frame when you try and open it? It is too close to the frame and needs to be adjusted. Is the door binding against the other door or the far side of the frame? In that case you want to move the pin closer to the frame.
You should probably take the door out when you make these adjustments. Lift the door up and tilt the bottom out of the opening.See the articles 'Removing a Bifold Door' and 'How To Install a Bifold Door' for instructions on taking the door in and out.
The problem with this is that you have to keep putting the door in and out to check the adjustments. With the door open you can hold onto the door (better yet, have someone else hold it), and loosen the set screw with the door in place. Adjust as needed and tighten the screw.
A properly aligned door should have a consistent margin along the top, sides and if it is a four panel door, down the center. For a four panel door the tops of the two doors should be even with each other and the center gap should be even. It takes a little practice to get the sense of how the movement of the pins affects the overall alignment of the door. Be patient, once you get the idea you'll always have that understanding.
Adjusting the Bottom Pivot Pin
Adjusting bifold pivot pins is a key element. The bottom pivot pin works similarly to the top one. The difference is that this pin is set in a toothed clip. To adjust the margin on the door you pick the door up and move it toward or farther away from the frame. The same adjustment principles apply with both pivot pins. Remember also, that moving the pin in or out also affects the top margin.
I know, sometimes it can be aggravating. Use a pry bar to lift the door and try to move it one notch at a time until you get it right. The notch system is a little less sensitive than sliding the top clip. You may need to make a minor adjustment on the top, once you have the bottom pin the way you like it.
Okay, I know, you're probably wondering why I didn't tell you to work on the bottom pin first. If it is clear that you will have to move both pins, then this is a good idea.
Unfortunately, it is usually not that clear and sometimes you go back and forth between the two of them, or four if it is a four panel door. Right, wrong or indifferent, I always start with the top pin. So that's how I wrote the article.
Keep making adjustments until everything lines up and the doors operate freely. It works like you expect. That is good news, you can continue repairing your other interior bifold doors. Only one was bad? Then your done, move on to your next project.