Author Topic: Steering Column Horn Assembly Help  (Read 1953 times)

Offline Rosa_Weaver

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Steering Column Horn Assembly Help
« on: July 31, 2021, 12:32:54 AM »
Hey all, I am hoping to get a little bit of assistance with the horn assembly on my 87 R10. Just recently I took it in to have the sloppy steering column fixed and found out that the last repair shop I took the truck to for repairs had broke the little plastic piece that the 3 screws go into to keep the horn from making contact. I'm hoping someone has found these before and might be able to point me in the right direction of where I can possibly buy another replacement one as I can't seem to find them locally and since I actually don't know what they originally looked like before its hard to tell if what I'm looking at online is the right one or not.

And I'm also wondering if anyone has a diagram of the horn assembly and how it is supposed to be put together as my chilton/haynes manual doesn't supply that apparently and I can't seem to find it online anywhere. Unless of course I'm just not putting in the right keywords to find it. lol Anyways, any help would be greatly appreciated as right now I don't have a horn.

Online bd

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Re: Steering Column Horn Assembly Help
« Reply #1 on: July 31, 2021, 12:27:05 PM »
The part you need is called a horn contact bushing.  The original GM part number is 12338143.  Fortunately, the steering columns in the GM family, as well as many other OEMs, were manufactured by Saginaw, so many parts are interchangeable between vehicle lines from year to year and model to model.  The color of the bushing your truck requires can vary from green to clear to white (see attached image).  Prior to 1973, there were dimensional differences in the bushing.  New old stock (NOS) and suitable substitutions are still available through Internet searches.

The plastic horn contact bushing (#3 in the schematic drawing) is an electrical insulator that allows the upper horn contact assembly (steel Belleville spring plate #2 and steel cup #4) to "float" between the plastic horn button cap (#6) and the steering wheel (#1).  When the horn button cap is depressed the Belleville spring distorts and contacts the bare steel hub of the steering wheel to complete the horn relay circuit to ground, sounding the horn. 

The schematic shows the order of assembly incorrectly; the order of the bushing (#3) and cup (#4) must be reversed.  That is, the Belleville spring (#2) is installed convex up against a plastic seat encircling the steering wheel hub, and the three towers of the plastic bushing (#3) drop through the three holes of the cup (#4) and Belleville spring (#3) from above the cup so that the spring resides undistorted and the assembly is allowed to float while remaining electrically insulated from ground.

Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline Rosa_Weaver

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Re: Steering Column Horn Assembly Help
« Reply #2 on: August 19, 2021, 08:29:40 PM »
Thanks bd for the reply. I apologize for the late reply. Been a lot of stuff I've had to deal with in my family recently that's had me tied up and sidetracked.

Got one of those bushings ordered from classicchevy.com so hoping it works out. Says it should fit my truck.

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