Perform these safety tests on your garage door system and contact a professional for repairs if it fails any of them. 

Garage door balance: 

• Disconnect the garage door from the opener so that it will operate manually. 
• Lift the door about halfway up, then release it. 
• The door should remain in place; if it slips down, the door isn't balanced. Call a service technician. 

Mechanical reverse feature: 

• Place a piece of wood or a brick on the garage floor in the path of the door. 
• Activate the garage door to close. 
• When the door contacts the block, it should reverse direction. If it does not, call a technician. 

Door photocell: 

• Locate the two photo sensors at the base of the garage door. 
• Check the alignment of the sensors; when they are properly aligned, they will light up. Adjust as needed. 
• Activate the garage door. As it closes, wave an object across the sensor path. The door should immediately reverse. 
• Test at least three different points in the beam's path. 

Tip: Garage door openers more than 20 years old may lack safety features such as these and may need an upgrade. 

The garage door hardware needs periodic inspection for signs of wear and tear.

• Check the garage door tracks and hinges. Use a socket wrench or screwdriver as needed to tighten any loose bolts or fasteners on moving parts. 
• Inspect for wear on any garage door rollers that are not attached to the lift cable system; steel rollers will show worn bearings and may look lopsided, while nylon rollers tend to crack as they age. Purchase and install replacement rollers as needed. 
• Look for wear in the lift cables attached to the door. You may see excessive rust, deterioration or broken strands in the cables. If they look worn, call for service. 

Safety: Do not try to replace garage door cables. They are under high tension and could cause serious injury if not handled by a professional. 

If you hear groaning or slapping sounds as the door operates, check the drive chain or belt as there may be a little bit of slack. 

• First, disconnect the opener from the power source. Raise the garage door to about chest height, detach it from the opener, and then close it by hand to work on the chain. 
• Locate the adjustment bolt that connects to the chain or belt. There should be nuts on either side to adjust the drive mechanism. 
• Use a wrench to turn the first nut at the side of the assembly counterclockwise. Then, move to the other nut and turn it clockwise. The chain or belt should pick up slack. 
• Tighten until the chain or belt is about 1/4 inch from the bottom of the rail. Do not over-tighten as it could lead to a break. 
• Reattach the door to the opener and reconnect the opener to the power supply. 
• Properly using garage door lubricant helps stave off corrosion in the metal parts. Some screw openers do not require lubrication, so be sure to read the manufacturer's recommendations first. 
• Lubricate the chain or screw with spray application white lithium grease. 

The garage door seals at the bottom of the door not only protect the garage from the elements, but also helps prevent vermin and snakes from creeping in under the door. The tension in the garage door springs makes it easier to raise and lower the door.

• Also called a U-shaped astragal, it should be replaced if the weather strip seems brittle or worn. 
• Detach the garage door from the opener so that it operates manually. 
• Raise the garage door to about chest height then secure a clamp over the track under the roller to keep the door in place while you work. 
• Use a screwdriver or pry bar to unseat the old weather stripping from the channel at the bottom of the door. 
• Once loosened, the weather strip should slide out if you pull a free end from the side of the garage door. 
• Clean the door groove to be free of any debris. Then, slide a new piece of weather seal into the door groove. 
• If the weather seal has trouble sliding into place, pull it all the way back out and apply penetrating oil to the groove. Then re-insert the new weather seal strip. 
• Trim the weather strip to about four inches beyond the door edge. Slide the strip to the left, fold the overage back in on itself, then slide back into the door groove. 
• Spray the overhead torsion or extension garage door springs with penetrating oil. Spray liberally and do not wipe off excess. 

Tip: Garage door springs are under high tension, so adjustment or replacement of springs requires extreme care. Consider hiring a garage door maintenance expert if a spring appears broken.

Keep the garage door clean and in good repair.

• Wooden garage doors should be wiped down with a clean, dry cloth. 
• Inspect the surface of the door to see if it needs repainting or staining or shows any signs of insect damage. 
• Patch any small holes with wood filler, lightly sand and then paint or stain as required. 
• Wash vinyl or other synthetic garage doors with a soft cloth and appropriate cleaner. 
• Thoroughly rinse the door with a hose, then dry with a microfiber cloth. 
• Brush down any cobwebs on the inside of the garage doors and wipe with a soft dry cloth. Go over any needed areas with a lightly dampened cloth. 

Unplug the garage door opener then try to open the door with the wall button. If it does not open, you need to replace the backup battery. 

• Using a screwdriver, remove the cover on the garage door opener and then replace the spent battery with a new one. 
• Replace the batteries in the door remotes. 
• Replace the garage door opener light bulbs with the size and wattage recommended in the manual. 

You may need to fix wheels that get stuck or bind in the garage door tracks. 

• Reduce the friction between the door and the track by adjusting the track brackets. 
• Loosen the nuts that hold the brackets to the door frame, and then make sure there’s about 1/4 to 1/2 inches of play between the door and the tracks. 

Adjusting the track brackets can also reduce friction between the door and the door stop. To adjust the track brackets, loosen the nuts that hold the track to the brackets, and move the track until the door doesn’t bind. 

If the overhead garage door opens too quickly or slowly, adjust the tension of the torsion springs. 

• Block the door open with a pair of locking pliers. 
• Change the position of the S-hook on the track brace. 
• Check the door speed and adjust the door springs until you get the desired result.