And I saw a leaking coolant in the back of an engine. Noo!!!
After some researches I find that it’s not just seal on a pump but seal inside a water pump impeller. This seal is called mechanical seal and it is know to fail.
Maybe one of the reasons is also a that previous owner didn’t mix coolant with water and with aging coolant became aggressive and eats seals. Also you should change coolant every 5 years. Bike also wasn’t used for a few years.
I ordered a seal on ebay and cost me a 35 eur. Not a cheap one.
Time to start striping a bike. Remove carbs, flush coolant. Then I was able to remove water pump cover and here is a seal.
I could see that it was rotating on a cup, not a good thing. It should rotate on a joint with impeler. I removed it without damaging a cup. Because cup is very hard to remove and pres without removing whole engine and rear cover. Too much work. I hope I won’t need to remove it in future 🙂
I cleaned surface really good. From new seal I needed to remove a cup. Seal is glued to a cup. So you need heat and patient to remove it. I cut it with a small grinding tool to remove it easily. Don’t damege a seal.
Cleaned surface and glued it back to a old cup with water pump gasket sealer.
Installed other part of a seal on impeller, use some soap between a surfaces so it won’t stick or run dry, that is how you avoid to damage a new seal. Also don’t run a bike without a coolant.
I put it back together and leave it some time to dry.
Than assemble the whole pump.
Time to for next repair.