Open the garage door until the bottom of the door is past the seam between the vertical track and the curve of the horizontal track. The two tracks join with a flag bracket that also helps sustain the pressure of the springs.
Clamp a pair of vise grips around the front edge of the horizontal track directly under the bottom door roller. The handles of the vise grips should point toward the center of the door. Place another pair of vise grips under the roller on the opposite side of the door.
Place the claw of a hammer over the top of the bent bracket, if the damage is to the bracket instead of the track. Pull the hammer to the left or right as necessary until the bracket is as straight as possible.
Remove the track bolts securing the vertical track to the wall brackets with a socket wrench to remove bent track. Most manufacturers use a single flat-head bolt through the track and bracket, secured by a nut. Some manufacturers use pop rivets. If your track has pop rivets, drill the rivets out with a 7/16-inch drill bit. Do not remove the track brackets or the flag brackets from the wall.
Bend the track straight with a pair of pliers or hammer as necessary. If the track is bent beyond repair, purchase a new piece of straight vertical track. Replacement track is available at home improvement centers and garage door dealers.
Attach the track to the wall and flag brackets with the straight side of the track pointing toward the wall. The track has a straight angle side and a curved side. Use 1/4-inch flat-head track bolts with nuts to secure the track to the brackets. The bolt heads should be flush to the inside of the track with the threads protruding through the track brackets. Tighten the nuts until they are hand tight only.
Hold the garage door open and release the vise grips from the track. Lower the door slowly, guiding the rollers through the vertical track. Push the track toward the wall until the face of the door is 1/8-inch from the door stop. Tighten the track bolts securely with the socket wrench.