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
RadiatorCrankcase Splitting
Remove the engine (see Engine Removal in the Engine
Removal/Installation chapter).
Set the engine on a clean surface and hold the engine
steady while parts are being removed.
Remove:
Cylinder Head (see Cylinder Head Removal in the Engine
Top End chapter)
Starter Motor (see Starter M ...
Cylinder Head Installation
NOTE
The camshaft cap is machined with the cylinder head,
so if a new cylinder head is installed, use the cap that
is supplied with the new head.
Install the dowel pins.
Replace the cylinder head gasket with a new one.
Replace the cylinder head bolt washers with new ones.
Apply molybden ...
Nozzle Assy Disassembly
Remove the nozzle assy (see Nozzle Assy Removal).
Pull out the secondary fuel injectors [A] from the delivery
pipe assy [B].
NOTE
Do not damage the insertion portions of the injectors
when they are pulled out from the delivery pipe assy.
NOTICE
Never drop the secondary fuel injecto ...