Ruby mk1 wiper motor advice needed

[Tony Griffiths]

Really useful pictures, thank you so much.
I have had to remanufacture the contact strip as the original had broken in half. It will need some fettling to get just right.
Also, it would appear that my handle doesn’t come out far enough.
Does the handle shaft slide within the spinning motor block? Mine is fixed (or stuck) so any in/out movement of the handle also moves the block up and down.
I have removed the screw from the head of the plastic knob but it won’t come off. Shouldn't it just slide off? Mine has a small split in it so I suspect there is some corrosion and don’t want to completely break the knob.

The knob should come off the shaft with the screw removed. One unit taken apart had a very thin-wire coil spring inside the knob - none of the others did.
One unit had the knob stuck so firmly to the shaft that it required a fine saw cut at the base of the taper and then careful prising off with a pair of small screwdrivers.
If the knob breaks, making a new one on a lathe should be too hard.