Horn Grounding PSA

[rebelyell]

I just spent the better part of 3 days dealing with a horn grounding problem in the column. I verified that the horns were good. Verified that the horn fuse had 12v. Verified the horn button worked. Had 12v at the horn.

Got all the way down to the horn ring in the steering wheel. It wouldn't make a ground to the turn signal switch when I pressed the horn button. Everything else was good. So I took a separate wire and touched the lead to ground. Horns worked.

Somewhere, the steering shaft had lost factory ground. There's one line in the FSM about a steering shaft bearing retainer using a staple to ground the steering shaft to the outer column. I pulled the column apart and found this tiny staple broken. Once I bought the new bearing retainer from Detroit Muscle, I decided it would be a good idea to check continuity across the bearing.

I did not have continuity across a ball bearing. Impossible, thought I. No way a ball bearing could not have continuity from inside race to outside. Well, it's possible. 50 years of dirt, grime, and grease had isolated the ball bearings from touching either race.

After soaking the bearing in simple green for a day and cleaning it up, the meter now beeps when you touch inner bearing surface to outer bearing surface.

So, to anyone wondering why their horns don't work: check that stupid little staple and check electrical continuity across your upper steering bearing.

[bdschnei]

Ideally a ball bearing doesn't "touch" either race. Rather it should be riding in a grease bath. Once it does start making significant contact with a race it will eventually lose its ability to turn within the races and stop turning all together creating a flat spot on the bearing. In the case of a wheel bearing which rotates at a fairly high speed (higher for some of us  ) that will eventually lead to the bearing failing.

Grounding through any type of bearing means current is flowing through that bearing which isn't desirable. Leads to bad things...
https://www.linearmotiontips.com/how-bearings-fail-a-closer-look-at-electric-current-damage/

That being said while a dry steering shaft bearing wouldn't be ideal, I would guess it would take a lot of steering wheel turns to begin damaging the bearing, although it might begin to develop an annoying squeak. I'm assuming the bearing came from the factory slightly lubed necessitating the grounding devise the engineers implemented.
 

[rebelyell]

You're not wrong on any of that for a bearing seeing high RPM or high amperage. For this steering wheel bearing, I bet I spun the outside around more times trying to get it clean than it has ever seen in it's lifetime. And if current flow through these bearings was a problem, I'm sure we'd have heard about it by now. I think the biggest flaw in this design is the staple. I may end up putting another staple in just for added security.

I'm sure I'll add a very light coat of axle grease to it just to smooth it out a little and prevent noise, but it's pretty smooth as-is right now.

This bearing was used up until the 90s. Some Mopar dealers still stock it. 2265656 is the current p/n. I'd like to see if they're greased new.

[bdschnei]

Yep, probably 99.9% of the time when that grounding staple breaks no one knows the difference since the horn just grounds through the bearing. You are the 0.1% the staple was meant for.. just took ~50 years. You should feel special... 

[Katfish]

Interesting, got a pic of the staple and fix?

[rebelyell]

I couldnt even get the horn to ground through the bearing or steering shaft. There was no path to ground from the shaft. The bearing and staple is that path. Now there is continuity from the inner bearing race to the staple.

[Katfish]

Not sure what I'm looking at?
Is that the staple?  It's embedded in some sort of Nylon coating on the bearing?

[dodj]

Not sure what I'm looking at?
Is that the staple?  It's embedded in some sort of Nylon coating on the bearing?

That is the rubber 'cup' the bearing sits in within the column. The staple is to help ground the outer race to inner.
I personally don't see how that is reliable...but the factory did do it.

[rebelyell]

Its not reliable at all. A lot of 70s trucks just had a switch on the dash.