Hi All I have just replaced the mechanical water pump seal in my Ducati 2002 748, i had removed the stator cover for cleaning up and ceramic coating so all the other seals were taken out then pressed back in also. Now its all back together the impellor seems excessively stiff, i presume that you should be able to flick the impellor and it spins freely. This does turn but you have to drag it around. The impellor was very tight going back through the seals, to the extent when i had to tap it through. There is no excess coating etc. blocking this. Also when i press on the impeller it should no doubt move about a millimeter because of the spring on the seal but its not bouncing back or moving. Does anyone know what the problem could be please, do not want to threebond the cover back on and find out its not pumping water correctly. Many thanks in advance.
Hi Shaun If you can talk through what's changed since you stripped it, then you are bound to get to the bottom of this. I think you hinted at the answer but just to confirm:- no ceramic coating was applied to any bearing journal diameters? What parts have you changed, and was it free to spin before you stripped it? Other than this, suggestions that come to mind are distortion during process (what temperature was involved?), wrong or damaged seals or bush/bearing.
I am thinking it may be the mechanical seal, i purchased an after market one of ebay and it seemed like a very tight fit. I shall strip it apart again tomorrow and inspect each item. Thanks for the response. When fitted correctly how each to spin should it be, is there any resistance or should you be able to flick the impellor to turn it?
Shaun, not sure exactly what you have done but the impeller should be free to turn, if you are removing the new seal you will need another new one. Just in case, the factory manual is available here 2002 748-748S.pdf (dropbox.com) pages 204 and 205 refer. Check for the correct seating of the snap ring on the rotor shaft
Chris, it needs reiterating as it looks like the pump is not correctly reassembled. Hope all is well with you these days
