Disassembly and assembly of the water pump (BMW 3 Series E21)

Disassembly

Remove the water pump.

Press off the hub using the Kukko 00 8 500 puller.

Remove the retaining ring, press the impeller off the pump shaft and press the bearing out of the pump housing.

Replace the bearing and seal.

Check the condition of the impeller and replace it if necessary.

Assembly

Press the bearing with the shaft, directing its long end towards the impeller.

Install the seal into the pump body.

Press the impeller on, applying a force of 440 kgf for a reused impeller or a force of about 500 kgf for a new impeller. In this case, it is necessary to maintain a gap of 0.6±0.2 mm between the impeller and the cover ring of the pump body.



Install the retaining ring.

Press the hub on, maintaining a dimension of 4.1+0.3 mm between the end of the shaft and the surface of the hub.