Why is one bolt on rag joint copper, it is insulated by rubber biscuit? i just painted it, do i need to leave bare metal contact somewhere for conductivity?

The horn button needs this for a ground. The button or switch gets it's ground from the steering shaft, not the column.

Thanks John. I learn something just about everyday on here. I changed the original rag joint on my 67 Elky a couple of years ago. There is a wire that connects a bolt on the column side to a bolt on the steering box side. I didn't know for sure what it was for and had never noticed such a wire on any other car...not saying there wasn't one, I just hadn't noticed one. I almost trashcanned that wire, but decided it had to have a function so left it. Now I know what it's for.

so what needs to connect to what? the column bolts to the rag joint, and the joint bolts to the steering box. how does the current get from the shaft to the box? and if the box is painted and the frame is painted the steering box is not even grounded anymore?

Originally posted by FO_FDYFO:
and if the box is painted and the frame is painted the steering box is not even grounded anymore? Same way a starter gets it's ground on a painted engine..through the bolt threads.

not to split hairs, but a starter threads into the block, the steering box uses bolts that go clear thru the frame and if the frame is painted the bolts do not conduct thru to the frame. i guess i will have to remove a bolt and chip the paint and primer off the frame under the bolt and washer?

It doesn’t need a large surface area to make a connection. The horn relay coil doesn’t draw much current. The box and its bolts probably bit in well enough on the inside of the frame.
I wouldn’t scratch any paint unless the steering shaft isn’t grounded. Measure continuity between the steering shaft and battery (-). It’s probably OK.

i will test it. but i still dont see any strap connecting one side of the rag joint to the other. the way it looks is, the shaft is isolated from the steering box. is this a wire, or a braided strap or a sheet metal strap? what does it connect to? does it go under the bolt that clamps the splines on to the steering box shaft then around to the copper stud? i would love to see a pic. graemlins/clonk.gif

I was curious about this myself. I once tried getting my horn to function but got some nasty shocks and didn't have time to finish it off. Does anybody have any pictures of this bolt/wire combo? Will any copper wire work?

--rO

Sorry, no pictures of that coupling. Maybe someone else has something.

There are two possible horn ground paths through the steering column.
First it can be grounded down through the steering column steering shaft, through the flexible coupling, and down through the gear to the frame. Second, it might also ground through the steering shaft into the upper or lower steering column bearing(s), up into the steering column jacket, into the mounting bracket(s) and into the body.

The rubber coupling disc is used to isolate engine noise and road shock from the driver. Because it is rubber it also effectively prevents any current from passing through it. So, originally, a small wire was added to connect one flexible coupling bolt to an adjacent stop pin. The wire was routed around the center of the coupling disc so you didn't see it unless you detached the steering column flange from the flexible coupling.

The wire was eventually changed to just a thin copper strip because if was cheaper.

Around 1970 the copper strip was eliminated when another design change went into production. Fine metal screening was molded into the face of the rubber coupling disc. The screen was just barely molded into the rubber so the top edges were exposed. When the coupling was assembled to the column flange, the screen transmitted the current between adjacent stop pins and coupling bolts. You can usually feel the ends of the screening by running your finger along one of the edges of the rubber disc.

All of the service flexible couplings have the molded screen in the rubber disc today.

I was the supervisor of the flexible coupling group at Saginaw Steering Gear Division back in 1972 when these changes occurred.

jiml82, thank you so much. it is amazingly wonderfull to have such a diverse aray of very knowledgable people on one site. i have been acused befor of over thinking things, but if i did not inquire about this it would have worked anyway but now i have larned something new.
thanks graemlins/thumbsup.gif

You know, I just rethought the lower strg column bearing. It is installed in a plastic adapter. So it cannot pass current from the steering shaft to the jacket. Also, when the turn signal (lock) housing was changed from a die casting to molded plastic in the late 70s their was no way for the current to go up through the steering column bearings into the jacket.

So the flexible coupling with the screen ground coupling disc is the primary way for the horn relay current to go to ground.

i can confirm everything you are saying. it does have a screen and i dug up one of my old steering boxes, it had the coupler on it with the wire attatched in the center of the rag joint. and that one did not have the screen built in. now i need to remove the paint under one of the frame mounting bolts to get good ground. great info! thanks again graemlins/beers.gif

The assembly plant never worried about removing paint from the frame. When the grounding current passed through the gear it could go down through the gear casting, through the bolts into the frame; or it could go down through the pitman arm into the linkage and into the steering knuckles or idler arm.

There are so many ways for the current to flow, I wouldn't worry about scraping off paint.

ok, i'll put a meter on it and check if i have a conductive path. ;)