If you have metal garage door rust, you don't have to replace the door. However, you must get to it right away, or the rust could eat a hole in the door, leaving it open to water and dirt. 

Rust can occur from the salt from the roads in winter along with the elements. The bottom panel is especially prone to rust. Here are tips to fix a rusty garage door.

Prepare to Work

For this project, you need:

• work gloves
• eye protection
• drop cloths or plastic
• painter's tape or masking tape
• spray bottle
• liquid dish soap  
• lint-free rag
• soft brush or bristle broom
• steel wool pad
• white vinegar
• baking soda (optional)
• auto body filler
• sandpaper
• palm sander
• rust-proof primer and paint 

Close the door. Detach the garage door from the opener by pulling the release cord. Shut off power from the breaker box.  

Spread drop cloths over areas you don't want touched by repair materials. Cover windows and door trim with painter's tape or masking tape.

Clean the Door

Mix several drops of dish soap and water in a spray bottle. Squirt the mixture on the door, and wipe it down with the rag. Rinse, and let the door dry.

Dampen the cloth in vinegar, and wipe the door. The vinegar should loosen the rust. Use a steel wool pad to scrape the rust.

To remove tough rust spots, mix baking soda with water until it makes  paste. Spread the paste on the door with a clean rag,, and leave it several minutes, then rinse. If you find holes patch them with auto body filler.

Sand and Prime

Attach sand paper to the palm sander. Sand the area; leaving about two inches past the rust line. Use a soft-bristle brush or bristle broom to clean sand dust.  For a smoother finish, repeat sanding with a finer-grit sandpaper.

Ensure the primer is compatible with metal. Spread a thin coat of the primer on the door with a paint brush or paint sprayer. If you use the sprayer, hold it a foot form the door; and spray in back and forth movements. 

Allow the primer to dry, which commonly takes about ninety minutes. Apply another coat, if needed. 

Empty the paint spryer , or get a clean paint brush. Mix the paint to match the color of the door. Apply the paint in thin, even coats. Add a second coat after the first coat dries, if needed.

Restore power, and reattach the door to the opener. Your door should look new again. If you don't trust your skill, or the garage door is seriously damaged, contact a garage door repair service.,