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

Water Pump Impeller Disassembly/Assembly
Water Pump Housing DisassemblyWiring Diagram (Other than US, CA and CAL without KIBS Models)
ZX1000JC
ZX1000JD
...
Coolant Deterioration Inspection
Remove the right lower fairing (see Lower Fairing Removal
in the Frame chapter).
Visually inspect the coolant in the reserve tank [A].
If whitish cotton-like wafts are observed, aluminum parts
in the cooling system are corroded. If the coolant is
brown, iron or steel parts are rusting. I ...
Caliper Installation
Install the caliper and brake hose lower end.
For the front caliper, be sure to install the collars [A].
Replace the washers on each side of hose fitting with new
ones.
Touch the brake hoses [A] to the stopper [B] of the caliper.
Front Calipers [C]
Rear Caliper [D]
Tighten:
To ...