If the surface is corroded or if the blades are damaged, replace the impeller

Water Pump Impeller Disassembly/Assembly
Water Pump Housing DisassemblyFront Seat Installation
Installation is the reverse of removal. Note the following.
Check that the dampers [A] are in place on the front seat.
Install the collars [B] as shown in the figure.
Place the seat hooks [A] under the fuel tank bracket [B].
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Special Tools
Bearing Puller:
57001-135
Head Pipe Outer Race Press Shaft:
57001-1075
Steering Stem Nut Wrench:
57001-1100
Bearing Driver Set:
57001-1129
Steering Stem Bearing Driver, 42.5:
57001-1344
Steering Stem Bearing Driver Adapter,
41.5:
57001-1345
Head Pipe Outer Race Driver, 55:
57001- ...
Hoses and Pipes
Hose Installation
Install the hoses and pipes, being careful to follow bending
direction. Avoid sharp bending, kinking, flattening or
twisting.
Run the hoses (see Cable, Wire, and Hose Routing section
in the Appendix chapter).
Install the clamp [A] as near as possible to the hose end
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