⚠️ SAFETY WARNING
- Do not operate the door - it can fall unexpectedly
- Do not attempt DIY repair - cables are under extreme tension
- Keep children and pets away from the door
- If door is stuck open - secure your home and call for emergency service
Why Does the Cable Come Off the Drum?
The cable drum is a grooved wheel at each top corner of the door that guides the lifting cable. When something goes wrong, the cable can jump out of its groove and unwind.
1. Broken Torsion Spring
The #1 cause. When a spring breaks, the cable instantly goes slack and jumps off the drum. You'll usually hear a loud bang when this happens.
2. Frayed or Worn Cable
Old cables develop frayed strands that catch on the drum grooves, eventually causing the cable to jump track. Cables should be replaced every 7-10 years.
3. Obstruction While Closing
If the door hits an object while closing, it can cause the cable to go slack momentarily and jump off the drum. The door then becomes unbalanced.
4. Misaligned Drum
If the drum has shifted on its shaft, the cable won't track properly. This often happens after DIY repairs or if mounting bolts loosen.
5. Manual Operation Error
Pulling the emergency release and lifting/lowering the door too quickly can cause the cable to jump. Always move the door slowly when disconnected from opener.
6. Bottom Bracket Failure
If the bottom bracket where the cable attaches breaks, the cable can whip up and come off the drum. This is often caused by corrosion.
How to Identify the Problem
Before calling for repair, here's how to identify what happened (observe from a safe distance):
Signs of a Broken Spring
- You heard a loud bang (like a gunshot) from the garage
- There's a visible gap in the torsion spring above the door
- The door feels extremely heavy if you try to lift it manually
- Both cables are slack or one side is lower than the other
Signs of Cable-Only Issue
- No loud noise occurred—cable just came off
- Spring appears intact (no gap)
- Only one cable is off the drum
- Door was hit by something or manually operated before the issue
Signs of Drum Problem
- Cable keeps coming off even after repair
- Drum appears tilted or loose
- Cable grooves on drum are worn smooth
Repair Costs in Toronto (2025)
| Repair Type | Parts | Total Cost |
|---|---|---|
| Cable rewinding only (cable intact) | $0 | $150-$180 |
| Cable replacement (one side) | $30-$50 | $180-$220 |
| Both cables replacement | $50-$80 | $200-$300 |
| Spring + cable (single spring) | $80-$120 | $240-$320 |
| Spring + cable (double spring) | $120-$180 | $350-$450 |
| Drum replacement (if damaged) | $40-$60 | $180-$250 |
All prices include labor. Emergency same-day service available at no extra charge in Toronto & GTA.
What Happens During Repair
Here's what a professional technician will do to fix a cable off the drum:
- Safety assessment - Inspect door position, spring condition, and secure the door from falling
- Release spring tension - Using specialized winding bars, unwind the torsion spring to make cables safe to handle
- Inspect all components - Check cable condition, drum grooves, bottom brackets, and springs for damage
- Replace damaged parts - If cables are frayed or spring is broken, install new components
- Rewind cable on drum - Carefully wind the cable back into the drum grooves
- Wind spring tension - Apply proper tension to balance the door weight
- Balance test - Test door at multiple positions to ensure proper balance
- Safety test - Verify auto-reverse and sensor functions if opener is connected
Time required: 45-90 minutes depending on complexity and whether springs need replacement.
Preventing Future Cable Issues
- Annual maintenance: Have springs and cables inspected yearly ($100-$120)
- Replace cables with springs: When replacing springs, replace cables too—they wear together
- Watch for fraying: If you see loose strands on cables, schedule replacement soon
- Proper manual operation: If using emergency release, move door slowly and steadily
- Clear obstructions: Keep the door path clear to prevent impact damage
- Lubricate drums: Apply light oil to drum shafts during annual maintenance
Frequently Asked Questions
Michael Thompson
IDEA Certified Garage Door Technician. 15+ years repairing cable and spring issues across Toronto & GTA.