I have a double door (18'). sectional door wood clad. The left side of the door (outside looking in) gets stuck about 4 inches from the bottom and reverses. It appears that the right side is about an inch lower than the left. How do I adjust the door height on the low side?
Thank you.
First of all we need to know what kind of springs system you have...
If you have two springs that point away from the door at a right angle...
That's a totally different situation than having the two springs parallel to the top of the door and wound around a steel rod... this second way is more tricky to work with... if not 'mechanically minded', may want to avoid working on this second system... can be very dangerous...
Both springs in either system try to lift the door (there is no spring pulling the door down, gravity does that)... as the up door slides off the horizontal tracks supporting it and moves downward toward the floor, more of the doors weight is transferred from the horizontal tracks onto the springs and proportionally, as the springs stretch more/are twisted more, they exert more and more lifting force on the door...
As others mentioned, when the door is about 3 feet above the floor, it should balance there/stay there all by itself... lift it some from that point and it tries to go higher on its own... lower it from that point and it starts trying to close itself... when fully closed it tries to stay down and closed...
For a smooth operating door, the tracks should be exactly parallel to each other at every point... in other words, exactly the same distance apart at every point... top, bottom, in between...
But before that, the tracks should be pointing out exactly 90 degrees out from the door... easiest way to determine that is measure from a garage side wall to a track... make sure the track is parallel to the side wall... then the other track is parallel to that track...
Are you sure the door is 18', 16' is more common?
Also, check the pulleys the cable rides on, make sure they aren't worn out, tipped at weird angles, the bearing balls haven't fallen out of them, the bearing balls have a dab of oil on them to lubricate/protect them, the bolt the pully spins on isn't loose or crooked, the pulley isn't split allowing the cable to ride lower down inside it, etc...