I had the old model with cast iron propeller and the pump was due to replace its internals anyways.
I saw some condensation in the oil level visor and also an strange liquid in the oil cap. Definitely some contamination in the pump.

Well with all apart, I think I need to replace the main pump shaft. See picture.
Have you guys with 55k miles rebuild your pumps already? If you add all seals and spacers goes over $300 easily.
Does anyone have a good indication where to get this part without forking US$250 asked by Maxbmw?

Thank you!

It wouldn't be surprising if years of idleness fostered enough condensation within the crankcase that would significantly dilute the oil into a creamy consistency. Maybe the pump seals are bad but maybe thoroughly flushing the crankcase then adding fresh oil would have mitigated the condition.

Regardless, forking over the dough to replace that part with new OEM is likely to significantly raise the odds of a successful repair.

No alternative , this shaft is dead, you need a brand new one. I also think that the mileage has no influence on the wear but the years do.

Post #74 in this recent link provides an image to give you an idea.  

https://www.k100-forum.com/t1112p50-waterpump-seal-special-tool#192200

Shop Motorworks or Motobins UK for better prices than you'll typically find stateside.

Two Wheels Better wrote:Shop Motorworks or Motobins UK for better prices than you'll typically find stateside.

Already ordered a few parts from Motobins. Thank you!

To answer your original question; I rebuilt my pump around 70,000 miles ago. I had an original Hotpoint TwinTub-style impeller in there that was a soild lump of rust. I replaced that with a s/h later impeller that had a slight wear band around the shaft. It's still running okay. If you're not happy about doing the job yourself, Motorworks will exchange your pump for a newly-overhauled one.

Dai wrote:To answer your original question; I rebuilt my pump around 70,000 miles ago. I had an original Hotpoint TwinTub-style impeller in there that was a soild lump of rust. I replaced that with a s/h later impeller that had a slight wear band around the shaft. It's still running okay. If you're not happy about doing the job yourself, Motorworks will exchange your pump for a newly-overhauled one.

I've already order all parts. I will give it a try.
Im assuming you're not talking about Mortorworks Chicago...
What would be the website of Motorworks you're talking about?