I have a two prong style contact wire on my 39 (VC) 1.5 ton truck... Everything is new, but the horn shorts out depending on how hard I press the button... Let me explain, with everything installed on the steering wheel (cup, rubber, and spring/not pushed all the way down) if I press on the horn lightly it will not work... As I apply more pressure to the side of the button the horn will work BUT as I turn the steering wheel left or right the horn will go off without pressing the button...
The remedy, pull the cup and rubber upwards with a screwdriver but then the horn does not work at all!... I can repeat the sequence and chase my tail over and over... Is there a kit out there for this style horn that actually works? If anyone has a similar working horn please let me know, thank you!
Can you provide pictures? I am not familiar with the '39 horn. My '37 has a rubber cup but no spring. The rubber cup acts as a spring, which is why original or NOS replacements don't work as the rubber is hard. There are two prongs which are not much more robust than wires, that stick down and ground the system, setting the horn to blow. I had to buy a second part and carefully ground the length to get satisfactory setup so it would function correctly. My 42 has a spring but very different construction. Kent
Last edited by Lightholder's Dad; 10/08/202112:40 AM.
Thank you for your reply... Believe the horn should be the same as your 37... I am attaching some photos. Imagine the trick is the length of the S wire... There is so much EXPENSIVE garbage out there- is not even funny-question is, which to buy which might work if you modify right!
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
I started filing the prongs only because they were uneven and it seemed to ge a little better, but then, the horn would go off still... It is such a crap shoot, since it will be affected depending on how far down your horn button is placed within the cup...
With all due respect, if it was good quality it would match EXACTLY the original one... Do you actually think that back then they had this much trouble with something as simple as a horn? I doubt it... Also INCORRECT is the gasket set for steering box (MES 123) offered for the 37-40 trucks... The gaskets are completely wrong in size (bottom too large/side, wrong shape and size) at least for the 1.5 ton trucks.. . Maybe this set fits all the smaller trucks only, but it should be indicated...
And while I am on a roll, I must say that the upper steering mast bearing (EL107) is also UNUSEABLE on a big truck steering column... It is actually too wide and will not go in even with lubricant (made of the wrong material/ Some king of shinny hard rubber plastic composite) that cannot be sanded down to fit the steering column... I TRIED! Again, expensive garbage! One frustrating thing after another... On the plus side, it is really tough, but dimensionally wrong...
I ended up re-using the original upper bearing after fitting a new wire which I damaged when removing it... All the time thinking it was the wire shorting out inside the column, instead it is the stupid S wire which it is still causing a problem...;(((
Can you tell I am annoyed??
As for fitting any upper bearing mast horn contact, the steering column has actually a small dimple that serves as a stop when fitting the mast bushing... If you're careful you should be able to remove the old without damaging the small stop bump...
Any idea of the length of your wire after you got done grinding it? I can certainly remove mine and measure it for reference...
Re-reading your first post you mention a spring, but your pictures and diagram do not show a spring. Is there a spring or not? My truck has no spring and the rubber cup acts like a spring due to its "springiness".
I am aware of the dimple that sets the depth of the mast bearing, however, the depth would still be dependent on how hard you pound on the bearing when you set it. So, some variability there.
Again, re-reading your first post you mention that the horn goes off when turning the steering wheel. If that is the case I interpret that to mean your prongs are still too long. Try filing or grinding a small amount off the ends, like 1/32 inch or so at a time until the horn seems to function.
I understand your frustration with the engineers who designed this and with the vendors that supply replacement parts. The fact that the engineers kept changing the basic design of the horn buttons between generations of trucks tells me they were searching for a more reliable design. I stand by my comment that with this design, due to the variability of tolerances of all the parts, that hand fitment, along with patience, is necessary. Good luck, Kent P.S. I am not at my shop for a while so I can't measure the length of my prongs. My above comments explain why I don't think it would be helpful, in any case.
Last edited by Lightholder's Dad; 10/08/20213:11 PM.
If I mentioned a spring, I was mistaken, there is no spring... It is just like the photos. I suppose you could drive the upper bearing down and not touch the dimple, so there are many variables in the equation when it comes to setting and installing the button... Still, junk parts are junk parts, and that is the biggest part of my frustration.
I will keep filing the contact wire and see if I can get it to work without shorting out...
Philippe, I am not sure what you mean by getting it to work without shorting out. The purpose of the prongs are to ground the horn circuit (in effect to short out the circuit) so that the horn blows. In this design, too long of prongs and the horn blows when you don't want it. Too short and the horn won't blow at all. The trick is to get the length just right so it blows with some pressure on the horn button, but not at other times. Kent
I understand how it works, the problem is that I have not filed the two prongs enough for them not to ground and accidentally set the horn off, as I turn the steering wheel left to right... I did not realize how much of a pain in the xxx this set up was going to be, but I just need to work on it a little more! Thanks for the help...
