Close your roll-up garage door if it remains open.
Examine your door's rails. The roll-up garage door's operation depends upon the rollers along these rails that move the door up and down. Mounting brackets along the door guide the rollers along their path, ensuring smooth operation. Use an adjustable wrench to remove the bolts holding one of the brackets in place, then slide the old mounting bracket off the door's rail.
Remove any other brackets along the door's rails using an adjustable wrench, if the brackets had not been removed previously, taking care to mark the positions of each bracket during removal.
Slide a replacement mounting bracket into one of the areas previously occupied by an old bracket. Insert the bolts that come with the bracket using your adjustable wretch, and turning it clockwise until the bolt is tight.
Replace all of the mounting brackets on the roll-up door with new brackets using your adjustable wrench.