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What to do when an extension spring breaks
Short answer
A broken extension spring leaves one side of the door without lift, so the door may hang crooked or refuse to open; HomeGuide puts replacing both side springs at about $120 to $200. Keep the door closed, do not run the opener, and call. Extension springs should be replaced in pairs and always with safety cables through them.
Warning signs
Signs a side spring has failed
A spring hanging loose or in two pieces
A broken extension spring is easy to spot on the side track.
The door lifts crooked
One side has lost its spring and lifts slower than the other.
The door is heavy and drops when released
Springs that have stretched out no longer balance the door.
No cable running through the spring
Without a containment cable, a breaking spring can fly across the garage.
A squealing pulley
Worn sheave pulleys wear cables and springs faster.
The job
How extension springs lift a door
Extension springs are mounted above the horizontal tracks on each side of the door. A cable runs from the bottom corner of the door, over a pulley on the spring, to a bracket at the back of the track. As the door closes the springs stretch and store energy; as it opens they contract and lift.
Because each side has its own spring, the two need to match. If one is replaced alone, the door lifts unevenly and the new spring works harder than the old one. That is why we replace them in pairs and check the cables and pulleys at the same time.
Stretched side springs
Replacing stretched side springs
Extension springs lose tension gradually, so a door can get heavier for months before one finally breaks. We size the new pair to the door's weight and height, not to the old spring's color code, because doors gain weight with insulation, new sections or windows. The door is then balanced so it stays put halfway up.
Missing safety cables
Adding safety cables
A safety cable runs through the center of each extension spring and is anchored at both ends. If the spring breaks, the cable keeps it from whipping across the garage. Many older doors were installed without them. We add them on every replacement, and on any door we service that is missing them.
Worn sheave pulleys
Worn sheave pulleys
The pulley on each spring and the fixed pulley at the track carry the lift cable. When their bearings wear, they squeal, wobble and fray the cable. Replacing pulleys with the springs costs little and keeps the new springs and cables from wearing out early. If the cables are frayed, the lift cables are replaced too.
Time
How long an extension spring replacement takes
Replacing a pair of extension springs with safety cables is usually done in a single visit. Worn pulleys or frayed cables add a little time but are typically handled on the same visit.
How the visit runs
How an extension spring visit runs
- 1
Secure the door
Door clamped down so the springs carry no load.
- 2
Size the springs
Matched pair for the door's weight and height.
- 3
Replace and contain
New springs with safety cables threaded through.
- 4
Check cables and pulleys
Worn pulleys and frayed cables replaced.
- 5
Balance and test
Halfway test, opener reset and safety reverse.
Around Naperville
Side springs in older Naperville garages
Bay Colony, built mostly in the 1970s, and Wheatland View, built in the early to mid 1970s, are the kind of Naperville neighborhoods where a garage door that has never been upgraded may still run on side extension springs. On those doors we check for safety cables first, since older installs often went without them. If the pulleys and brackets are worn too, we price a torsion conversion alongside the repair.
Do it yourself or call
What is safe to check, and what is not
Extension springs are under tension whenever the door is down.
Fine to do yourself
- Look for a broken spring or a missing safety cable from the floor
- Listen for squealing pulleys and note which side
- Keep the door closed and the opener unplugged after a break
- Lubricate the springs and pulleys twice a year
Leave to a technician
- Removing or installing springs on a loaded door
- Adjusting cable length and balance
- Replacing pulleys and track brackets
- Converting to a torsion system
Cost
What an extension spring replacement costs
HomeGuide puts replacing both side extension springs at about this range. It is a planning figure, not our quote.
- Spring size for the door's weight and height
- Safety cables added
- Pulleys or lift cables replaced
- Door balance adjustments
- An overnight or holiday call
Answers
Questions about extension spring replacement
Yes. They work as a pair, and a new spring beside an old one lifts the door unevenly.
A cable through each spring that contains it if it breaks. Every extension spring should have one.
No. One side has no lift, and the door can twist or drop. Keep it closed and call.
They are rated in cycles, like torsion springs, so heavy use wears them faster. Most give years of service before stretching out.
If the door, pulleys and brackets are worn, a torsion conversion can be worth pricing. On a sound door, new extension springs work well.
Same group
Related door work we handle
Torsion Spring Replacement
The broken spring over the door replaced, sized to the door's real weight.
Extension to Torsion Spring Conversion
Side springs swapped for a torsion shaft above the door for a steadier lift.
Garage Door Tune-Up
A balance test, a safety reverse check and tightened hardware before winter.