Kenno, I don't have a solution myself, but, given the amount of times I've read the thread I've been posting in, I do remember the following quotes:
Convertible Mini wrote:
The little finger contacts that contact on the disc are often found to be destroyed as there had been a shorth through them as a result of wiring connected wrong. Ruining these contacts makes the Motors unrepairable as these contacts are not available any more.
So, the fingers are NLA. So, you can't buy new. Maybe you could swap them in from another wiper motor..? Or...
drmini in aust wrote:
I'm going to silver solder (SBA45) the tips of the 3 finger contacts on my bad one.
If I clamp a pair of pointy vicegrips on the copper strip it'll stop the nylon body from melting. I hope...

Further on in that thread, DrMini said that he had the motor working (on the bench). I can't find anything to advise how long lasting the solder's been.
In another thread, I also found this:
GT mowog wrote:
Mmmm.....thought as much. The last one I rebuilt I soft soldered a piece of brazing rod on to. Still going OK.
The one before that I put a micro switch on to. It get a lot of use and have never missed a beat. No good on a restoration though.....
So... There's three options. Swap in the fingers and nylon body from another wiper motor, solder the end with a very strong solder, or solder on an alternative tip (e.g. brazing rod). Hope you can get it sorted.
