If any one of the parts is damaged, replace the mechanical seal as a unit.
Rubber Seal [A] Mechanical Seal [B]

Water Pump Housing Assembly
RadiatorSubthrottle Sensor Resistance Inspection
Turn the ignition switch to OFF.
Disconnect the subthrottle sensor connector.
Connect a digital meter [A] to the subthrottle sensor connector
[B].
Measure the subthrottle sensor resistance.
Subthrottle Sensor Resistance
Connections: BL lead [D] ←→ BR/BK lead [C]
Standard: ...
Cylinder Head Removal
Remove:
Thermostat Housing (see Thermostat Removal in the
Cooling System chapter)
Exhaust Pipe (see Exhaust Pipe Removal)
Camshafts (see Camshaft Removal)
Heat Insulation Plate [A] (see Engine Removal in the
Engine Removal/Installation chapter)
Place a container under the coolant dr ...
Air Suction Valve Inspection
Remove the air suction valve (see Air Suction Valve Removal).
Visually inspect the reeds [A] for cracks, folds, warps,
heat damage or other damage.
If there is any doubt as to the condition of the reeds, replace
the air suction valve as an assembly.
Check the reed contact areas [B] of ...