RE. there are some
worrying yet subtle grooves in the shaft and I have read on various forums that the shaft should be replaced if so which I concur also
Could you post photos of the shaft? Is the pump shaft leaking/weeping externally?
Do you have water in your engine oil that would indicate leakage into the crankcase via the seals?
If the damage on the shaft is in the bearing surface and not the seal surface the shaft could be reusable.
If the shaft is really gone I will look for one for you here in Japan.
RE; I know as it is Yanmar I will need another bank loan (lol), I am waiting on a quote from the USA and there is one I can get from the UK for around $250AUD...Have also sent a few emails out this morning..which leads me to the second question:
when should the water pump be replaced as a whole (and it includes the shaft?)? As mine is 40+ years old, rarely serviced/rebuilt I am somewhat leaning towards buying a new pump for peace of mind and
rebuilding that at appropriate intervals whilst keeping the current one as a spare..Aftermarket $500/Yanmar $660. I may have answered my own question there!
Thanks in advance
when should the water pump be replaced as a whole (and it includes the shaft?)?The pump housing is bronze and as long as there is no severe damage, gouges or wear it could last 100 years (not joking).
So there is not recommended replacement period on the complete pump.
rebuilding that at appropriate intervals
Now that you have the pump out and apart it would be a good time to rebuild.
The two seals, two bearings and O-ring can be bought at any bearing supply shop without paying the YANMAR surcharge.
You can make the gasket (make a spare while you are at it) and only really need a new impeller.
gary