Philippe,
Thanks for the pictures and yes, that is the same for my '37. It took two tries to get it right but what I did was grind the ends of the two prongs of the S wire very slightly until the horn functioned correctly. Those prongs ground the system on the brass mast bushing, so the length is very important. On my first attempt I ended up grinding them too short so I had to order another S wire. I purchased mine from Jim Carter and they were good quality. The length would be dependent on not only on the S-wire but the thickness of the mast bushing, the depth of the seating of the mast bushing and the thickness of the rubber cup, so I think final fitment of the part will always be necessary.
Kent
