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MG MGB Technical - Early horn push question
|I'm trying to fit an original wire spoked steering wheel and horn push to my early 67 roadster. The car currently has a Mountney wheel fitted with a wire connected through the steering column onto the horn button but it seems that the wire twists as the wheel rotates. The origimal set-up appears to have had some kind of sprung loaded contact assembly in the centre of the steering column but it is missing. Moss say this item is not available so I need to either make one up or find an alternative. I have the original steering wheel and horn button assembly, what do the three small screws in the wheel hub clamp onto? The horn assembly has a sprung steel plate on the underside secured with three nylon nuts, should it have a cover of some kind?. All suggestions and advice gratefully received.|
|Originally there would have been a fixed copper/brass contact (with a purple/black wire) on the column which rubbed on a slip-ring on the back of the wheel. One of the many breakers or 2nd-hand parts houses should be able to help. Can't help with the innards of the wheel, except to say that the horn switch connects a ground picked up from the steering shaft through to the slip-ring.|
|Paul Hunt 2|
I happen to be doing just the same right now. I have the 67 steering shaft on the bench and will be happy to take some pictures of it. Does your turn signal have a brass finger sticking off of it? That is what touches the sleeve on the column. There should also be a spring loaded cable runing up to the top of the steering column.
|I have a photo of a brand new early horn slip ring if it would help. Send me an email if you would like a copy.|
Here are some pictures of the steering column. Also of the turn signal bar that rides on the brass collar.
This is my old turn signal. There should be a little brass nub on the end.
The plastic item on the end of the shaft is where the push unit contacts the column.
|The contact assembly you are looking for Roger is called the the Horn Pencil. It is available from MGB Hive at a cost of £5.25. I'm quite sure that they can also supply a slip ring perhaps not new as they have over a hundred cars which they are constantly breaking. Phone them on 01945 700500|
|AFAIK the horn pencil is what fits inside the wheel boss, and connects between the shaft and slip-ring (which is part of the wheel). This is called the brush by Moss which seems just as confusing. The fixed contact that is mounted on the turn switch and bears on the slip-ring as the wheel turns, which is what Roger seems to be missing, is something different.|
Clicked on Bruce's link and all I got was what looked like a default page.
|Paul Hunt 2|
|Thanks for all the input guys, I got it sorted out. The confusion on my part comes from the fact that the previous owner had cut off the upper contact on the purple/black live wire and soldered a different fitting to suit the aftermarket wheel. The original set-up is this: There are two plastic shells which fit under the slip ring to insulate it from the steering column. The live wire has a small sprung contact which sits in a pocket in one half of the plastic shell and the brass contact touches the inside of the brass slip ring thus making a contact. The other end of the wire has another brass contact which makes with the underside of the horn button. This contact sits in a nylon insulator bush which fits inside the steering column and it has a spring under it to apply force and maintain contact against the horn as the wheel turns. There is a tiny E clip on this contact to allow it to be retained once it is passed through the plastic bush. The sprung plate on the horn button assembly is nipped in place by the three 4BA screws. It looks a bit feeble, but it works. Once you have all the bits and pieces it's easy to figure it out.|
I have got to change photo sites. I always have problems listing the site.
Here is the home page. The Steering column pictures are listed there.
Sounds like roger got it figured out.
This thread was discussed between 23/11/2005 and 29/11/2005
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