I believe your 40 is the same as my 37 and that the upper bushing has the horn contact ring and wire hooked to it. The bushing/bearing/contact is no longer avalible from any of the suppliers I checked with. You will want to be carefull in getting yours out. First step is to pull the mast from the column because the bushing has to come out of the top or steering wheel side. I uses a long steel pipe that was just smaller than the mast tubing and carefully drove the bushing out. If you look at the top of the mast you will see where it gets smaller in diameter and has a small tab pireced in it. This is where the bushing stops. They seems to be made of wood with a leather inner rub surface at least mine was. Mine was totaly shot so I made a new one out of hard Maple wood. I drill the new holes and mounted the horn ring just like the old one. Then I soaked it in motor oil for two weeks so it wouldn't dry out.

The horn contact ring is just a piece of stamped brass with three short legs and a wire soldered to one of them. I just cleaned it all up and soldered on a new 16 gauge wire extra long.

Its been in for a year now and still working great. I had to buy three feet of wood and only used about three inches of it. I have extra if you need some. Joe

1937 Chevrolet Inline-powered Streetrod