Shut off the water supply, drain home, determine to make and model of the fixture by pulling handles, remove the trim collar and packing ring, pull cartridges, inspect cartridges and springs, check valve body, clear debris and buildup deposits or scale from the valve body, install new cartridges, seats, and springs, reinstall packing bonnet, reconnect trim, tighten handles, check for smooth operation, test and clean up the work area