This will help you create a flat and level surface so the gap will close.
How to adjust how far a garage door closes.
There are two ways that you can adjust garage door track.
Open the garage door and watch it closely as it opens.
Adjust the springs on both sides of the door the same way.
Place a stepladder beneath the box portion of the garage door opener.
If there s a slight gap at the bottom of your garage door then a garage door threshold is a great option.
By pushing the door back into position you should have made the vertical track straighten.
If this has happened to you you can add more concrete to the floor in order to bring it back up to the right level.
Identify the switches by the up or open.
Install a garage door threshold.
If it was opening too quickly move it to the next lower hole.
Once the spring is free of tension remove from its track hanger.
Look for two limit adjustment screws.
2 you can adjust the track so that the door aligns with the weatherstripping.
Find the limit switch and the adjustment screws that will allow you to adjust the position where your door stops when it closes.
Have a helper steady the ladder.
You may need a flashlight.
Garage doors are very easy to adjust and can be done in less than 15 minutes.
How to do a simple adjustment on a garage door opener.
How to do a simple adjustment on a garage door opener.
When the garage door opens about halfway or 5 feet from the ground and stops the up limit switch needs to be adjusted.
Push the door back to adjust the door and get the center aligned again.
1 you can align the track with the door itself so that the rollers work properly.
It is possible that the vertical track down the side has gone out of alignment and shifted due to a slightly loose lag screw.
With a screwdriver adjust these screws.
These limits must be set correctly for the door height to have a proper seal as well as to allow for adequate clearance.
Check that it is straight.
How to adjust a garage door to close completely.
A related topic would be adjusting garage door springs.
If the door was closing too quickly move the spring to the next higher hole on the bracket.