Certain doors in your home may contain self-closing hinges. These hinges are spring-loaded and, once installed, apply enough spring tension to close the door automatically. Garage entry doors and doors to utility or mechanical rooms typically have these types of springs. Keeping the spring tension high enough to keep the door closed is important as it ensures that doors to dangerous rooms close on their own, limiting access to children. The spring tension can be adjusted with a hex wrench.
Insert the hex wrench into the hex-shaped hole in the center of the hinge.
Apply pressure to the spring by turning the hex key clockwise. This takes pressure off of the tension pin.
Remove the tension pin while the spring is still under pressure. Use needle-nose pliers, if necessary.
Turn the hex wrench clockwise to increase tension. Reinsert the tension pin into the next available slot. Remove the hex wrench. Repeat the procedure for each hinge on the door.
Open the door and let go. The tension of the hinges should close the door completely, latching it shut without manual effort. If it doesn't shut and latch on its own, repeat the previous steps for each hinge, increasing tension a little at a time.