This cone has notches in it that are used to adjust the tension in the torsion spring.
How to loosen garage door spring.
Put on eye.
Attached to the garage door track and loosen an inch or two.
The cable is attached to the door and runs to an s hook that attaches to the track support.
This end may be simply looped through the holes in the track or it could be attached by means of a special clip and an s hook.
Adjust the lift cable to make fine adjustments try adjusting the lifting cable instead of the spring.
Look for a reddish cone on the torsion spring.
Position a sturdy ladder to the side of the springs rather than working directly in front of them for safety reasons.
In either case adjust both sides equally either by shortening the cable or by repositioning the s hook in a different hole in.
Step 1 unplug the garage door opener and clamp the door to the track.
With the door propped open take the s hook out of the support and tighten or loosen the cable as needed.