We recommend weighing your garage door to confirm the torsion spring dimensions. This weight, along with the information regarding the door height, track radius and drums, will help us determine the correct springs to balance your door.
Important: Do not use a digital scale. Regular analog bathroom scales adjust the reading as the weight changes, but most digital bathroom scales are designed to register weight in a narrow window of time. The better commercial scales for weighing packages do tend to be reliable as they will register changes in weight as they occur.
Remove the opener arm. Disengaging the trolley from the drawbar carriage is not enough. Often the outer carriage will catch on the inner carriage resulting in a false reading. Failure to disengage the opener will not only distort the weight you get but it could also damage your door and opener.
Position an analog scale with a board on it in front of the center of the door.
If your door has two springs and both are broken, or if your door has only one spring and it is broken, reinstall the cables on the cable drums at this time.
Next, pull down on the cone of the broken spring with a winding bar or pull down on the shaft with a large pipe wrench. This will lift the door. Slide the scale under the door. Lower the door onto the scale. Take a reading.
If both springs were broken, or if only one spring was broken, shake the door to make sure it is free in the tracks and read the weight of the door.
If you have a heavier door that weighs more than 150 pounds with one spring still wound, you will need to use 2 scales and position them under the first row of hinges from each end of the garage door.
Next, if you have one spring that is still wound, push up 1/4 turn on the winding bar or pipe wrench to loosen the cables slightly and to place the full weight of the garage door on the scale. While pushing up on the bar shake the door to make sure it's free in the tracks. Make sure the cables remain loose as you do this.
Read the scale while continuing to push up on the winding bar or pipe wrench. Both cables should be loose when reading the scale. If your scale has a small dial you will need a second person to read the weight. After reading the weight lower the winding bar or pipe wrench to allow the spring tension to transfer to the cable drums and cables. Reverse the previous steps to remove the scale from under the door