Don't remind me, I went there with my '78 boxer engine!
As far as I know, the only differences between early and late water pump designs were the change from an interference fit alloy housing to one with a steel sleeve.
- Mine definetly had an alloy housing. It was chisseled off nicely...
But there is a major difference in design, I will have to upload some better pictures, so you can see it for yourself. Basically, its the impeller (as kevjtd calls it, I don't know what the name is - English is a second language to me, but it's the circulating part) that is too big - it is designed as if there is a groove in the back of the mounting hole in the engine block in which it can fit, but that isn't the case!
My '78 engine (from a S2 'Sud) had the alloy body and had to be broken apart to get it out. Looks like you have the same original part Oelholm. I had a spare 105 boxer engine with a recent water pump, so I raided that for a replacement. The steel sleeve made removal from the block CONSIDERABLY easier, and once I'd cleared all the swarf and years of accumulated sediment that had collected over the years, the steel body pump was a straight fit.
- According to my sources (
) the difference in design was implemented in around 1976 - so still S1.
Is the impellor pressed onto the shaft? It may not have been pressed fully home - this happened to a friend of mine with an AMC 390 pump. A quick job in a bench press sorted it - it may work for you too, if you are prepared to take a chance. Failing that, it might be worth a comparison with another new boxer pump.
- Looking at the new pump, it seems impossible. I am all for people posting pictures of their coolant pumps, I would love to see some of the other designs..!
Good luck finding a replacement - you've done the hard part!
- It would seem not
Three hours of sweaty, manual labour is far
more desirable than the situation I've gotten myself into.