Same problem, Miele W1986 drain pump.
I bought my W1986 in summer of 1997.
It uses the same pump, 4251170 120V/60Hz 90W.
The washer has had very light use and is in near perfect condition.
I can't believe a simple drain pump is going to obsolete a machine that is in otherwise perfect condition. Shame on you Miele.
The problem is that the bushing around the impeller shaft that seals to the bottom of the impeller housing and cleanout is very loose and leaks water around the shaft when it drains, soaking the floor. The seal between the bushing and the pump housing is fine. It's just very loose and floppy on the shaft, like a rubber grommet or o ring blew out. I've gently tried to take the impeller off the shaft, but that doesn't seem removeable and I was afraid of breaking it.
So, now I'm looking to build a Franken-pump. I want to cobble together some kind of pump from commonly available parts that will be around for years.
At this point I don't care how pretty it looks, so I'll probably cut some access panels in the sides so I don't have to flip it to work on it in the future.
I've also considered cannibalizing it for parts and selling them on e-bay. Miele lists the drain-pump on their website as selling for $238 (the very fine gray print says discontinued that you don't see until after you try to purchase it in the shopping cart.)
Such a shame. It's a beautiful piece of well engineered equipment. But the service and parts availability really stink. I'm so soured by this, I don't think I'll ever buy a Miele product again.
Has anyone else figured out how to retrofit another responsible brands pump to this washer?
I've considered finding a pump/impeller/motor that fits in to the housing and 3D printing an adapter. Anyone done this?
