Noisy, shuddering or uneven doors
Noise is diagnostic. A rhythmic squeal that speeds up with the door is dry roller bearings. A metallic grinding is a roller running on a damaged track or a bearing that has collapsed. A deep bang partway through travel is usually a hinge or a section joint taking load it should not be taking. A rattling that changes when the door is nearly closed points at loose track brackets.
Shuddering, where the door climbs in a series of jerks, is a balance problem: the springs no longer match the door weight and the motor is dragging it. Left alone it will end in a burnt motor or a snapped spring, and it is exactly the fault an annual garage door maintenance visit is designed to catch.
The garage door will not open
A door that refuses to open is usually a broken torsion spring. The motor will strain, hum, or move a few centimetres and stop, because without spring assistance it is being asked to lift the door's full weight — often more than 100kg on a double sectional. Look at the spring above the door: a broken one has a visible gap, like a spiral cut in half.
The second most common cause is a snapped or derailed lift cable, which leaves one side of the door lower than the other. The third is an opener fault — a stripped drive gear or a failed board — where the motor runs but nothing moves.
Do not keep pressing the remote. Every attempt after a spring or cable failure drags the door further out of square and turns a straightforward spring repair into track and panel damage as well.
The garage door will not close
A door that opens but refuses to close is almost always the safety beams. The two infrared sensors mounted low on either side of the opening must see each other; a spider web, a bag leaning against one, a knocked bracket or a lens covered in dust breaks the beam and the opener refuses to close as designed. Most units flash an error code on the head unit while this is happening.
If the beams are clear and aligned, the next suspects are the down-travel limit setting and the close-force setting on the control board. A door that closes fully and then immediately reverses is being told it has hit an obstruction — usually because the limit is set slightly too low and the door is pressing into the floor.