Disassembling the pump is quite labor-intensive, so in case of a malfunction we recommend replacing the pump as a whole.
You will need an 8 mm wrench.
1. Drain the cooling system (see "Replacing the coolant").
2. Remove the timing belt (see "Replacing the timing belt and its tension roller").

3. Remove the six water pump mounting bolts and remove the water pump.
4. Install the water pump and all removed parts in reverse order.