One Side of My Garage Door Is Higher Than the Other - Causes and Solutions
Noticed the door looks crooked when it closes? One corner sitting lower than the other, or a gap on one side that isn't there on the other? This is one of those things that's easy to ignore because the door still moves - but it shouldn't be ignored because it usually means something is off in the system and it tends to get worse.
Here's what actually causes it and how to sort it out.
Broken or weakened spring on one side
On doors with two torsion springs, the springs share the load. If one breaks or loses tension significantly faster than the other - which does happen - the door becomes heavier on that side. The opener still moves it but the door hangs lower on the weaker side.
Look above the door at the springs on the bar. Both should look similar - same coil density, same length, no visible gap or break anywhere. If one has a gap in the coil, it's broken. If one looks visibly different from the other - coils stretched farther apart, looks more fatigued - it's losing tension.
Broken spring means calling someone. Not a DIY repair. Losing tension means the spring needs adjustment or replacement, also best left to a tech because torsion springs are under serious load.
If yours has only one spring - single spring setup common on smaller doors - a single spring losing tension will make the whole door feel heavy and drop, but it wouldn't cause the side-to-side height difference. That's more specific to a two-spring setup where the two sides can be at different tensions.
Cable came off or snapped on one side
Two cables, one on each side of the door. They run from the bottom corners up to drums on the spring bar. If a cable snaps or comes off its drum on one side, that corner of the door loses its support and drops.
This is usually obvious. The door sits dramatically lower on one side. You might see a cable hanging loose. The door might not open at all if the imbalance is severe enough.
Stop using the opener if this is what you're seeing. Running the opener against a door with a failed cable bends tracks, strains the motor, and can cause the door to come down in a dangerous way.
Cable repair - call someone. Cables work directly with the spring system and there's tension involved in that area.
Rollers worn unevenly or one side has a roller out of track
Less dramatic than a broken cable but still causes uneven door position. If rollers on one side are significantly more worn than the other - or if a roller on one side has popped out of the track - that side sits differently.
Look at the rollers on both sides while the door is closed. Visibly different height or angle between the two sides? Look at where the rollers sit in the track - both sides should look the same. If one side has a roller that's sitting partly out or in a wrong position, that's your cause.
Roller back in the track is fixable yourself in a minor situation - one roller out, door still mostly in position, nothing bent. More than that, call someone.
Track on one side is bent or shifted
Track bracket comes loose over time from vibration. When the track shifts position - even slightly - the rollers riding through it travel a different path. The door follows that path and ends up sitting at a different height on that side.
Look at the track brackets on both sides. Do both tracks look parallel to each other and parallel to the door? Any section where one track angles slightly differently? Any bracket that looks loose or pulled away from the wall?
Minor bracket tightening is a DIY fix - socket wrench, snug everything up. If the track itself is bent from impact, that's a replacement or reshaping job.
Opener trolley arm adjusted differently on each side
The arm connecting the opener to the door has adjustment points. If the arm was adjusted or reinstalled incorrectly - or got bent somehow - the door can end up pulled unevenly.
Look at the opener arm. It should be straight and attach to the door header bracket symmetrically. If it looks bent or the connection points look uneven, that could be contributing.
The door itself is warped
Wood doors especially, but also steel doors that took damage - panels can warp or bend in a way that makes the door appear uneven even when the hardware is set correctly.
Look at the door panels when the door is closed. Are they flat and aligned? Any section that's bowing or kicked out? A warped door panel changes how the door sits in the frame.
Minor warping on a steel panel can sometimes be carefully adjusted. Significant warping usually means panel replacement.
How to actually figure out which one it is
Start with the visual stuff. Is a cable hanging loose? Visible break in one of the springs? Those are obvious.
Then do the balance test. Disconnect the opener, lift the door manually to waist height, let go. Does it hold? Does one side drop faster than the other? If one corner consistently drops, that side has less counterbalance - spring tension issue on that side.
Look at the tracks and rollers. Are both sides tracking the same way? Any roller sitting differently on one side?
Look at the track brackets - are both tracks still mounted securely and parallel?
If the spring or cable is involved - call someone. If it's loose track brackets or a single roller out of position - those are manageable yourself.
Uneven doors almost always have a fixable cause. It's rarely a coincidence - something specific happened or wore out and the door is showing you which side.
GarageDoorRepairz can come take a look, figure out exactly which side is the issue and why, and get the door sitting level again. Give us a call.
What happens when you leave an uneven door running
The opener is the first thing that takes damage. When the door is heavier on one side, the trolley and door arm experience lateral stress - a sideways pull they're not designed to handle. The arm can bend. The trolley can wear unevenly. The track on the heavier side gets more pressure from the rollers.
Tracks can bend from sustained uneven loading. Rollers on the low side wear faster because they're carrying more weight. The opener motor works harder every cycle.
A door that's slightly uneven and gets used for six months without being fixed can cause damage that costs significantly more to repair than the original issue would have. The original problem might have been a $75 bracket tightening. By the time you deal with what it caused, you're looking at tracks, rollers, and opener arm.
Checking spring balance as part of the diagnosis
Even if the door doesn't look dramatically uneven, spring balance is worth checking on any door that's showing asymmetric behavior.
Disconnect the opener, lift the door to waist height, let go. Watch which corner drops first or drops faster. That's the side with less counterbalance. It's not always dramatic - sometimes one side drops just slightly faster than the other, but consistently. That consistency is what tells you it's a tension issue rather than a random fluctuation.
If both sides drop evenly and fairly fast - both springs are losing tension. If one side specifically drops - the tension difference is side-to-side.
For a two-spring door, this diagnosis helps pinpoint which spring is the issue even before a tech arrives. When you call, you can say "the left side drops faster in the balance test" and a good tech knows immediately what to look at first.
Prevention - keeping things even over time
Have the door balanced checked every couple of years. This takes two minutes during any service visit and catches spring tension loss before it becomes a visible problem.
Replace both springs at the same time when one fails. This keeps both sides at the same tension level from the same starting point. Springs that go in together wear together more evenly.
Tighten track brackets once a year. A quick check with a socket wrench around all the bracket bolts takes ten minutes and prevents the gradual track drift that causes one side to travel differently over time.
Don't force the door through resistance. If the opener is struggling or the door feels heavy or uneven, stop and figure out why rather than pressing through. The damage from forcing a door that's already off-balance accumulates fast.
GarageDoorRepairz - call us and we'll get the door level and figure out what caused the imbalance so it doesn't come back.