Inspect the bow to ensure there is no damage that might be affecting the sound quality. You may not need to re-hair if you notice cracks or bends in the bow.
Remove your old hair connection piece by lifting the top section of the bow tip. Be gentle, but this requires a bit of force to jar the piece from the string. Unscrew with your hand the "frog" section, which is under the connection piece at the tip.
Grip the hair in a bundle and secure the top into the tip of the bow. Screw in by hand the bottom part of the frog piece.
Unscrew with your hand the base of the bow. This will detach it from your mortise eyelet and your bottom frog. Unscrew the eyelet with your hand. Hand screw your new eyelet into your frog. Place back the frog in the mortise. Tighten the screw back into your hole at the violin's base. Tighten your screw until your playing tension is about 1/4-inch from your cambre, which is the center of the bow.