206 water pump disassembly

I usually press the pulley hub off the shaft. Then I remove the set screw and press the cartridge bearing/seal/impeller out of the housing as a unit. The impeller is made out of cast iron and is also used as the seal ride. It is typically corroded beyond use. There are new impellers that have better vane design and are made from brass. You can press the impeller off of the bearing shaft once the bearing is out of the housing.
For reassembly I press the bearing into the housing, then lock it in place with the set screw. Then I press the pulley hub onto the shaft. Then install the seal in the housing and then press the impeller onto the bearing shaft until the clearance between the impeller vanes and housing is correct.

 

there is a good tutorial here

https://www.ferrarichat.com/forum/threads/water-pump-rebuild-pictures.239352/

although you should make sure the gap between the housing and impeller is 0.5 - 1mm max as per the manufacturers manual. not the face of the impeller to housing as shown on this demonstration.

Buy a new shaft and bearing as these are one unit and cannot be replaced separately, the bearing race is part of the shaft so just discard it.

Good idea to fit a new impeller but check the parts you are buying as some of these after market parts leave a lot to be desired.
Tony

 

The original cast iron impellers were induction hardened where the face of the impeller meets the carbon seal. Maranello had some remade decades ago but didn't do the hardening procedure and they leaked prematurely. I wonder how the brass impellers will hold up.

 

New water pumps that I have seen have a different design mechanical seal and don't use the impeller as the opposing seal face.

 

Tony,

thanks for emphasising the correction to the tutorial. Ironically the cooling has performed impeccably since, including battling the M25 traffic jam in 34degC on way back from national concours. May be the clearance front and back are similar... i.e. I got lucky.

Ben,

I know yours is a 206 and may well be different, but if you are measuring during dismantle and re-build, may be useful to share both the front and back clearance...

Kevin

 

I don't think you got lucky. I think you would get away with the larger gap but the overall pump efficiency will be reduced as water can circulate back through the eye of the impeller if its too large. The cooling system is very forgiving and well over engineered to cope with a vast variety of situations, not just our mad summer.

hope you enjoyed the NC, picked a good day to go.

Best
tony