The crooked door, and why you should stop touching it
A garage door that is hanging at an angle — one side higher than the other, jammed partway, or resting on the floor on one side and open on the other — has lost the thing that was keeping it level. On a sectional door that is one of the two lifting cables, which run from the bottom corners of the door up to drums on the spring shaft. When one cable frays through, slips off its drum, or its drum lets go, that side of the door drops and the other side stays up. The door is now held by one cable carrying a load meant for two, and a hundred-kilogram panel is one more tug from coming down.
The advice for a crooked door is the same as for a snapped spring: stop. Do not run the motor, because it will either jam harder or pull the good cable off its drum too. Do not try to level it by hand. Do not pull the manual release, which lets the good side drop. Leave it, keep people out of the garage, and call. A door in that state is secured in place before it is repaired, and it is treated as an emergency at any hour because it is a hazard rather than an inconvenience.
Cables and tracks fail together
They almost never fail separately, and repairing one without the other is why the same door comes back a month later. A cable frays because it has been running over a damaged drum, or because the door has been lifting unevenly against a bent track for months and the cable on the harder side has been carrying more than its share. A track bends because a roller has seized and the door has been dragging, or because a cable let go and the door slewed sideways into it. Whichever went first, by the time the door is crooked, both need looking at.
So a cable and track repair is a set of jobs done together. The cables are replaced as a pair, because the surviving one has done the same cycles as the one that broke. The drums are checked for wear and grooving. The tracks are inspected along their length for bends, dents and loosened brackets, and straightened or replaced in sections. The rollers — the small wheels that run in the track — are checked, and the seized or flat-spotted ones swapped, because a bad roller is usually where the whole sequence started. Then the door is balanced and cycled.
The door that jumped its track
A door does not need a cable failure to come off its track. A roller can jump out of a track that has been bent by a car bumper, or that has worked loose from the wall, or where the track's radius at the top is worn. When that happens the door binds, the motor strains, and the panel at the affected roller starts to tilt. Caught early it is a small job — the roller is reseated, the track is straightened and re-fixed, and the cause is dealt with. Caught late it becomes a crooked door, a bent panel and a cable job as well.
The early signs are worth knowing. A door that has started to make a scraping or grinding noise on one side. A door that shudders partway through its travel. A door that the motor now struggles with at one particular height. Each is a roller or a track beginning to bind, and each is cheaper this week than next month.
What the coast does to cables and tracks
Lifting cables are steel wire, and the salt air on the Atlantic Seaboard, the West Coast and False Bay corrodes them from the inside — a cable can look sound and be half its original strength. Tracks rust at the fixings and the bottom bends, where water collects. On a coastal door, cables and rollers are replaced on a shorter interval than the same parts inland, and stainless or coated versions are worth the premium where the door faces the sea. A door in Sea Point that has never had its cables looked at in ten years is a door waiting for a Saturday morning.
Sand is the West Coast's version of the same problem. It gets into tracks and roller bearings, and a roller that is running on grit wears its track and itself. Clearing and lubricating the tracks — with the right lubricant, not a general-purpose spray that attracts more sand — is the maintenance that keeps a Blouberg door running, and it is done as part of any cable and track visit.
On the day
The door is secured first — clamped in position if it is crooked, blocked if it is off its track — and then the sequence above runs: cables replaced as a pair, drums checked, tracks straightened or replaced, rollers swapped where they are bad, the door levelled and balanced, and only then the motor reconnected and the door cycled. Most cable and track repairs are done in one to two hours with parts from the van. Where a panel has been bent in the failure, which happens when a door slews hard, the panel replacement is quoted at the same time and done in the same visit where the panel is stocked.
Where the failure has also killed the motor — a motor that was straining against a jammed door for long enough will strip its gear — the motor repair is diagnosed as part of the same visit and quoted separately, so you can see exactly what each part of the job costs.