Glacier Bay faucets may start leaking due to worn parts inside the cartridge. This cartridge is the main water control valve in the unit and, if the seals split or crack, not only will it leak, but water temperature and flow rates are often affected. Replacing this part is something anyone can do; it only takes about a half-hour and requires a minimal amount of tools and parts.
Turn off the water line to the faucet.
Pull out the cap on the lever of the faucet handle with your fingers and loosen the screw under it with the Allen wrench. Slide the handle off by pulling it back and away from the faucet base.
Remove the escutcheon (a plate under the handle) screws with a regular Phillips screwdriver and remove this part. If necessary, remove the trim plate by unscrewing the two screws holding this to the wall, and remove it.
Remove the cartridge retainer (a metal sleeve on the cartridge) by turning it left with a wrench or large pliers. Pull the cartridge out of the faucet head. Apply silicone grease to the bottom of the new cartridge. Insert it by pushing it into the faucet head.
Replace the cartridge retainer and tighten it. Replace the trim and escutcheon and re-thread and tighten the screws.
Install the handle by sliding it onto the stem of the new cartridge. Tighten up the retaining screw with your Allen wrench.