Water Filter Head Assembly - Rebuild (8-13) Section 8 - Cooling System - Group 08 M11 Page 8-46 Remove the capscrew (1), and the washers (2 and 3) from the filter head. Use a pair of pliers to remove the shutoff valve shaft (4) from the filter head. Remove the o-ring (1) and spring washer (2) from the shutoff valve shaft. Cleaning Use solvent to clean the parts. Dry with compressed air. Inspection Visually inspect the filter head and water filter element sealing surface (1) for cracks or damage.