If it was opening too quickly move it to the next lower hole.
How to balance a garage door with a torsion spring.
Adjustment to torsion springs can be dangerous because they must be adjusted with the door down and the spring under tension.
Stand a stepladder at the area of the motor and unplug the power cord to the opener.
A problem with the spring tension could cause the door to open or close unevenly improperly or at the wrong speed and adjusting the springs will likely solve the problem.
Pull down on the emergency release handle to disconnect the door from the opener track.
The bar also has a pulley at each end through which the garage door cables that open and close it pass.
Open it just as wide as you can without hitting the garage door opener s stop bolt and place a clamp on the track on both sides to keep the door in.
There are many schools of thought about garage door torsion springs and their replacement.
Locate the torsion springs on the bar above the garage door.
If the door was closing too quickly move the spring to the next higher hole on the bracket.
Look at the wall just above the garage door.
Once the spring is free of tension remove from its track hanger.
Adjusting an extension spring door.
Torsion springs must be adjusted with the door in the down position.
Adjust the springs on both sides of the door the same way.
Numerous websites and videos showing you how to change them yourself using galvanized or oil soaked some will count the number of coils within a certain measurement to determine the wire diameter of the torsion spring some will use a spring gauge to determine the wire diameter of the torsion spring.
Spot the bar that runs parallel to the top of the garage door and has 2 springs on it.
Close the garage door.
Be sure to have all your tools inside before closing the door unless you have an alternate access door to the garage.
Retest the door balance as you did in step 1.