Garage door hangs crooked or one side is lower

A garage door that sits at an angle, or has one side lower than the other, has lost its balance. The cause is often a cable, drum, spring or track, all of which carry dangerous load. This guide covers what to look for by eye and why you should not run the door.

Running a misaligned door can bend the track, damage the panels and strain the opener, and it can bring the door down. Nothing below needs the door to move.

A garage door is lifted by cables on both sides, working with the springs. Both sides must lift at the same rate. When one side lifts more than the other, the door tilts. Manufacturers and service providers point to the same short list of causes.

• A stretched or frayed cable. When one cable stretches or frays, it becomes longer than the other, and the longer side can sit higher.
• A loose or slipping drum. If a drum is not seated flush or begins to slip, the cable can wrap unevenly.
• A worn bearing. A bearing that wears or shifts can leave the cable at the wrong angle.
• Uneven or failing spring tension. A fatigued spring stores less energy and the cables can no longer lift the door properly.
• Bent track or damaged panels. Impact, such as a vehicle bumping the door, can bend a track or panel so the door cannot travel straight.
• A past installation or adjustment error. Incorrect spring turns or mismatched cable lengths can leave the door out of balance from the start.

A cable that has come off its drum on one side is a common result. The unbroken side stays under tension, so the door hangs unevenly and is unsafe to run.

• The bottom edge of the door is no longer parallel to the floor.
• The door shifts sideways or looks racked or tilted in the opening.
• A cable looks slack, frayed or hanging, or is off its drum.
• You hear grinding, popping or scraping when the door moves.
• The opener strains or stops partway. See opener reverses or stops partway.

A door that does not move smoothly may be in an unsafe condition, according to DASMA. A crooked door has already told you that.

These checks are visual only. The door stays where it is.

1. From a few feet back on the floor, look at whether the bottom edge is level with the floor and whether the door sits square in the opening.
2. Look at the two lift cables, one at each bottom corner. Are both taut and in line, or is one slack, frayed or off its drum?
3. Look at the springs. On a torsion system, look for a gap in a coil. On an extension system, look for a stretched or separated spring and a safety cable.
4. Look along both tracks for dents, bends or gaps where a roller may have left the track.
5. Take photos of the corners, drums, springs and tracks from where you stand, and note when it started and whether anything hit the door.

If you find any of these, that is the end of your checking. You do not need to find the exact cause. One service provider says plainly that looking is always safe, and that if you see fraying, slack cable or uneven lifting, you should stop using the door and arrange service.

A crooked door always needs a technician. Bring one in right away if you see:

• One side lower than the other, or a door that tilts or sticks.
• A slack, frayed, hanging or off-drum cable.
• A gap in a torsion coil, or a stretched or separated extension spring.
• A bent track, an off-track roller or a damaged panel.
• A door that makes new grinding, popping or scraping sounds.

Releasing spring tension, reseating drums, replacing cables and re-tensioning springs are technician work. Bottom brackets, where the cable anchors, are under constant tension and must never be loosened by a homeowner. DASMA says frayed cables should be replaced only by a trained technician.

Our technicians inspect the door and confirm the cause first. Depending on what we find, the repair may be cable repair, spring replacement, track repair and alignment, off-track door repair or a panel replacement. After the work, the door is checked for level travel and balance.

For related reading see garage door off its track, bent or misaligned tracks and frayed or snapped cable.

• Garage Door Cable Repair
• Garage Door Spring Replacement
• Garage Door Track Repair and Alignment
• Off-Track Garage Door Repair

• A1 Garage Door Service: Garage door misalignment vs balance
• Affordable Door Co: Garage door cable tension explained
• DASMA: Garage door safety