MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG Midget and Sprite Technical - Earth on steering column?

I have a 1964 MkII midget and have fitted a new horn. The circuit is completed through the earth contact made when the horn push is depressed. However the column doesn't appear to be earthed. I bought the car in boxes and so didn't see it dismantled. Can anyone tell me please how the column is earthed. Reading the archives it appears that there was a strap connected somewhere. Does anyoone know? If I connect a crocdile clip to the clamp bolt that attaches to the steering rack and earth it to the bodywork, the horn operates fine when the hornpush is pressed.
Thanks.
Neil
Neil (K series)

If you have painted the steering column and rack, the earth is now shielded by the paint.
The rack is isolated via the paper shims, and the only earth is through the steering arms but the are isolated by the rubber front end bushings.
A fresh earth strap will fix it but there was never an earth strap on the steering rack or column. You can install a wire at the column to body clamp under the dash, but again the column is isolated by the felt bushings inside. If that does not work, ground it at the rack to the body.
Frank Clarici

Hello Frank,
Thanks for the response. You said "If you have painted the steering column and rack, the earth is now shielded by the paint". But how was it earthed? Is it earthed through the inner or outer column?
Neil (K series)

Earth was through the column to rack to frame, ie majic. The majic goes away with paint. A wire from rack to frame should do; one from column to frame is better, but it winds up. So you use a very flexible test lead wire and loosely wrap it around the column a couple of times, and replace it after a few years.

FRM
FR Millmore

Hi Neil - I had exactly the same prob with my Sprite -to sort it I just made up a short strap and fitted two "ring" type connectors. One was big enough to slip under one of the two small bolts that hold the "end cap" on the rack and the other end earthed to one of the radiator shroud fixings - worked a treat - I've stuck a picture of it on for you - cheers - Neal


N Broadbent

Neil,I seem to remember my 1970 car had an earth strap from the rack end cap bolt as seen in Neals picture to under the head of one of the rack bolts that goes into the chassis. It looked like a factory fitment to me.The problem is the inner column(that is what you need to earth) and rack are all mounted in rubber bushes of some sort so you will have to bridge that gap. The solution in the photo from Neal seems sensible to me.
Mike
m fairclough

Thank you all. N Broadbent (Neal?) thanks for the photo. I will try it tonight. I'll update you if I get it working.
Neil
Neil (K series)

If I remember previous discussions correctly, there is a bush for the column that was originally bronze, but is worn so is replaced in recon units with nylon. Probably that bush at the top of the rack in the photo. Thus the earth is lost, or becomes unreliable.

Anyone confirm this?
Andy
Andy Pie-Crust

I have a '66 and the rack was never rebuilt (I've owned it since '72). The original bushing on that rack is nylon. Even if it were bronze it would not provide a reliable path to ground. There is a felt washer below it.

Paul
Paul Noeth

Hmm thanks Paul. It's definitely a common problem, related to column earthing which was seen as acceptable at the factory, but deteriorates with wear. I've found either turning the wheel or even leaning on the screen sometimes deflects the scuttle enough to make an earth! Most sensible people do what Neil has done.

I was late for my MOT......




Andy Pie-Crust

This is just a guess, but I think the horn is grounded through the turn signal assembly. See photo. There is a wiper that rubs on the inner column. It is attached to a purple wire with black tracer that passes through the switch and into the wiring harness.

There is also a black wire (not visible in the photo) which attaches to the turn signal bracket which mounts to the outer column. The black wire also goes into the wiring harness.

So the outer housing is grounded through the switch backet, the horn switch makes the contact between the inner and outer columns, and current travels back down the inner column and out through the wiper. Or vise versa depending on the polarity of ground.


Paul Noeth

I can happily report that my horn is now grounded. I followed Neals (N Broadbent) advice and made up an earth connection that is fixed to one of the bolts that hold the endcap at the end of the inner column and fixed the other end to a bolt on the radiator stanchion. Hey presto. It works a treat. Thanks all.
Neil (K series)

Hi Neil,

glad you sorted it! I have to admit I've really gone to town on earthing a lot of my car's electrics - especially the rear light units which are also supposed to ground to the car body. I've again fitted round connectors to the rear light fixing studs and strapped them to the body too - cheers, Neal
N Broadbent

This thread was discussed between 06/01/2010 and 08/01/2010

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.