How do you fix water pump on a 91 Mazda 323?

To fix the water pump on a 1991 Mazda 323, first, disconnect the negative battery cable and drain the coolant. Remove the serpentine belt and any components obstructing access to the water pump, such as the timing cover or brackets. Unbolt the old water pump, clean the mounting surface, and install the new pump with a new gasket. Finally, reassemble everything, refill the coolant, and check for leaks after running the engine.