I found the instructions for replacing the 13168 water valve. I have listed them below.
| Instructions: Removal|
1. Shut off water supply from toilet and disconnect water line from its rear. Remove nuts at base of toilet. Lift toilet off the flange.Turn upside down.
2. Remove old flange seal from toilet or floor flange.
3. Remove Seat and Cover by gently pulling backward at 45° until they disengage from toilet. Turn toilet upside down, with back facing you, on a padded work surface. Remove Mechanism Cover and Water Valve: loosen screw behind and to right of Water Valve.Loosen four housing screws located in 3, 7, 9 and 11 o’clock positions. Remove two Water Valve anchoring screws.Turn toilet upright.
4. Grasp Mechanism Cover by hinge opening and gently lift and tilt off, exposing lever spring, link and water valve. Restrain left end of lever spring while disengaging right end carefully from spring notch and set aside. Disconnect link from water lever and from water valve arm hole with a twisting action. Remove Water Valve and Float Assembly.
1. Place Float Assembly in upright position before installing water valve.
2. Place O-ring on water valve neck. Turn toilet upside down. Install water valve with two anchoring screws.
3. Turn toilet upright. Re-engage link and lever spring into locked positions. Set Mechanism Cover in place and turn toilet upside down.
4. Install four mechanism screws in place. Turn toilet upright. Reattach Seat and Cover. Apply new flange seal. Remount to floor.Connect water line.