Cracked Garage Door Hinge? What the Numbers Mean and What It Costs

The numbers stamped on your hinges are not decoration

Look at the flat face of any hinge on your door and you will find a number stamped into the steel, usually 1 through 5. That number is the roller offset — how far the roller stem sits proud of the door face. It exists because a sectional door does not travel in a straight line. As each panel rounds the curve from the vertical track into the horizontal, it needs to sit slightly further back than the panel below it, or the panels would jam against each other.

So the numbering climbs as you go up the door. The joint between the bottom two panels takes #1 hinges; the next joint up takes #2, then #3, and so on. On a four-panel door you will typically see #1, #2 and #3 in that order. Some manufacturers add a letter — a #11 or a #1B is a variant offset for a specific track radius, not a different number entirely.

The practical consequence: if a hinge gets replaced with the wrong number, the door binds. A number too low pulls the panel in and the roller runs tight against the track flange; a number too high pushes it out and the panel scrapes the header seal. Both show up as a door that is suddenly rougher or noisier than it was, and both are easy to mistake for a track alignment problem.

End hinges and centre hinges do different jobs

Every panel joint has hinges at both ends, where the door meets the track, and one or more in the middle. They look similar and they fail differently. The end hinges carry a roller and therefore carry load — the weight of every panel below them transfers through that hinge into the roller and the track. Centre hinges have no roller; they keep the panels aligned and stop the door flexing across its width.

End hinges usually fail at the roller sleeve. The round tube the roller stem sits in wears oval under years of load, the roller starts to wobble, and eventually the sleeve splits along its seam. Once that happens the roller has room to climb, and a door with a split sleeve is one hard cycle away from coming off its track.

Centre hinges usually fail at the knuckle — the barrel where the two leaves pivot. On a wide double door with only one centre hinge per joint, panel flex works that knuckle every cycle until it cracks. You will often hear it before you see it: a sharp pop or clack at the same point in the door’s travel, every time.

How a cracked hinge fails — and what it takes with it

Hinge cracks are fatigue cracks. They start as a hairline at a stress riser — the corner of a stamped hole, the base of the knuckle — and they grow a little on each of the thousand-odd cycles a door does in a year. This is not a "keep an eye on it" repair. A hinge that is visibly cracked today is measurably more cracked next month.

What makes it worth acting on quickly is what fails next. A hinge that lets go under load drops that corner of the panel; the roller is pulled sideways out of the track, and the door racks. At best you get a derailed door. At worst the panel above creases at the point of load, and a creased panel is a panel replacement rather than a $20 part.

Rust is the other route to failure, and Ontario is hard on hinges for a specific reason: salt-laden slush drips off the car onto the garage floor, evaporates, and the resulting damp salty air sits inside an unheated garage all winter. Builder-grade 18-gauge hinges rust from the inside of the knuckle outward, so the first sign is often stiffness and a rust bloom at the pivot rather than obvious corrosion on the face.

Replacing a hinge — and the one you must never unbolt

A centre hinge on a closed door is one of the genuinely approachable repairs on a garage door. With the door fully closed and the opener unplugged, the panels are resting on the floor and the hinge is not under load; four lag screws or carriage bolts come out, the new hinge goes on with the same number stamped on it, and the fasteners are torqued back down. Work one hinge at a time.

End hinges are a step harder because the roller has to come out of the track and the hinge is carrying panel weight even when the door is closed. Done wrong, the panel corner drops. It is doable, but it is the point where most homeowners are better off calling.

The one that is never a DIY job is the bottom bracket. It sits at the lower corner of the bottom panel, it looks like an oversized end hinge, and it is the anchor point for the lift cable. With the torsion spring wound, that bracket is holding the entire weight of the door through a cable under extreme tension. Unbolting one is a recognised cause of serious injury in this trade. If the part you want to replace has a cable attached to it, stop.

What hinge replacement costs in London, Ontario

A hinge itself is a $6 to $20 part. What you are paying for is the visit, the correct numbers matched to your door, and the balance and safety check afterwards. In London and the surrounding 50 km, a standalone call to replace one or several hinges runs $149 to $229 all-in, parts and labour, with a 1-year warranty. Added to a $150 tune-up the same work typically adds $10 to $40, because the technician is already on the ladder with the hardware inspection done.

If more than two or three hinges have cracked, we will usually recommend doing all of them at once and stepping up to 14-gauge galvanised stock. The parts cost difference across a door is small, the labour is identical, and it removes the whole failure mode for the remaining life of the door. Doors that have had a derailment are the other case for a full replacement — hinges bend in that event even when they do not visibly crack.

Worth checking at the same visit: hinges and rollers wear together, because a wobbling roller is what elongates a hinge sleeve in the first place. Replacing one without inspecting the other tends to bring you back. We service doors across London, Old North, Masonville, Byron, St. Thomas and Aylmer.

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