Cable Replacement
Replacing lift cables on torsion spring sectional overhead door systems. Covers securing the door, disconnecting the operator, fully unwinding the torsion springs, removing the old cables from the drums and bottom brackets, inspecting hardware, installing and seating new cables, pre-tensioning, rewinding the springs to the original turn count, and testing door balance and safety devices.
Warnings
This procedure must only be performed by trained, qualified door service technicians experienced with torsion spring systems. Improper spring handling can result in serious injury or death.
Cable replacement on torsion spring systems requires fully unwinding the springs. Torsion springs store lethal amounts of energy. Follow all safe spring-handling practices.
ALWAYS use properly sized winding bars. Never use screwdrivers, rebar, or other improvised tools.
Never stand directly in front of or behind the winding cone while unwinding or winding springs.
Cables under tension can snap and whip. Wear eye protection at all times. Do not place any body part between the cable and the drum or bracket.
Required PPE
- Safety glasses
- Leather gloves
- Steel-toed boots
- Hard hat
Tools Required
- Replacement lift cables (correct length and loop/stop size for the door)
- Winding bars (2) — proper size for winding cone
- Socket set and wrenches (3/8", 7/16", 1/2", 9/16")
- Allen wrench set (for set screws)
- Vise grips / locking pliers (2 pair)
- Pliers
- Tape measure
- Stepladder rated for your weight plus tools
- Permanent marker or chalk
- Lubricant (light machine oil)
Procedure — 8 Steps
Step 1
Close, Secure, and Disconnect the Operator
This procedure must only be performed by trained, qualified door service technicians experienced with torsion spring systems. Improper spring handling can result in serious injury or death. Confirm the door is fully closed, clamped, and the operator is de-energized and disengaged before doing anything else.
Lower the door to the fully closed position. Clamp vise grips to the vertical track just above the bottom roller on each side to prevent the door from moving during the procedure. Then disconnect power to the automatic operator — unplug it or turn off the breaker. Pull the emergency release handle to disengage the trolley from the door arm so the operator cannot drive the door while you work. For commercial installations, follow full lockout/tagout procedure per OSHA 29 CFR 1910.147.
Pro Tips
- Set the vise grips snugly against the track just above the bottom roller so the door physically cannot travel upward.
- For commercial jobs, apply your own lock and tag to the disconnect — never rely on someone else's.
- Verify the clamps hold by giving the door a firm upward tug before proceeding.
- Take a photo of the operator wiring and mounting before disconnecting so reconnection is straightforward.
Checklist
Training Videos
Disclaimer: These videos are produced by third-party YouTube channels and are not affiliated with Doorbot. Video content may not align exactly with the procedures above, may depict techniques that differ from DASMA or manufacturer recommendations, and may show tasks that are dangerous if performed without proper training and equipment. Always follow the written procedure, your company's safety policies, and applicable industry standards. Use these videos as supplementary reference only.
References & Standards
- DASMA TDS-190 — Factors Affecting Spring Cycle Life
- Door manufacturer installation manual
- Cable manufacturer specifications for wire rope diameter and construction