MGB & GT Forum
Repairing Lucas 9H Windtone Horn
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Hello all!
In all the older vehicles I've ever owned, I've always tried to get the stock horns working. A deep, throaty exhaust note is wonderful, but there's something so conversational and cheerful about a horn. They add so much character, to a breed of car already overflowing with it.
Now imagine my disappointment when the Windtone horns on my 1976 MGB were not working when we first purchased the car. There's some funny stuff going on with the horn wiring in the car, so I thought I'd take them out and try them on the bench first.
When I connected them directly to the battery, the high tone would not sound. Hitting it with a hammer and playing with the adjustment screws would not bring it back to life, so I set about taking it apart.
In brief, I used a Dremel with a zipdisk to cut the rivets off the body, then punched them through and out. I was then able to separate the horn into it's three main components; the upper portion with the winding, the diaphragm, and the bottom with the resonance chamber.
There was pretty good resistance through the coil, but no resistance across the contacts or the contact breaker. The culprit turned out to be the contact breaker itself. I was able to separate the breaker with my thumb, and removed some built up carbon with sand paper and brake cleaner. 30 minutes and I was suddenly getting something close to factory spec through it again! I finished the work, cleaned the surfaces with a wire wheel, cut new paper gaskets, and bolted it back up.
Success! A nice, loud tone. I'm going to do the same with the working low tone horn, then repaint them both.
Any thoughts on paint colour? The factory colour was black, but I'm tempted to do it in something close to the MG Maroon.
Would a more in-depth write up be worthy of the tech library? It's not complicated, but there's not much literature on it.
Thanks!
Jack
Remember; I'm pulling for ya. We're all in this together.
1976 MGB "Scoob" - Our summer touring machine
In all the older vehicles I've ever owned, I've always tried to get the stock horns working. A deep, throaty exhaust note is wonderful, but there's something so conversational and cheerful about a horn. They add so much character, to a breed of car already overflowing with it.
Now imagine my disappointment when the Windtone horns on my 1976 MGB were not working when we first purchased the car. There's some funny stuff going on with the horn wiring in the car, so I thought I'd take them out and try them on the bench first.
When I connected them directly to the battery, the high tone would not sound. Hitting it with a hammer and playing with the adjustment screws would not bring it back to life, so I set about taking it apart.
In brief, I used a Dremel with a zipdisk to cut the rivets off the body, then punched them through and out. I was then able to separate the horn into it's three main components; the upper portion with the winding, the diaphragm, and the bottom with the resonance chamber.
There was pretty good resistance through the coil, but no resistance across the contacts or the contact breaker. The culprit turned out to be the contact breaker itself. I was able to separate the breaker with my thumb, and removed some built up carbon with sand paper and brake cleaner. 30 minutes and I was suddenly getting something close to factory spec through it again! I finished the work, cleaned the surfaces with a wire wheel, cut new paper gaskets, and bolted it back up.
Success! A nice, loud tone. I'm going to do the same with the working low tone horn, then repaint them both.
Any thoughts on paint colour? The factory colour was black, but I'm tempted to do it in something close to the MG Maroon.
Would a more in-depth write up be worthy of the tech library? It's not complicated, but there's not much literature on it.
Thanks!
Jack
Remember; I'm pulling for ya. We're all in this together.
1976 MGB "Scoob" - Our summer touring machine
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CameraZOOM-20180408153540600.jpg 47.7 KB
 Cambridge, ON, Canada
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Apr 21, 2018 08:57 AM
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 Joined 20 years ago
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 Great White North, QC, Canada
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Apr 21, 2018 03:25 PM
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Good one Jack. 
Mark and Anthony H helped me through my horn 'correction' as well. Not so daunting once you get in there.
On one of my horns I needed to replace a Lucar tang . I used a bolt rather than the brass rivet which broke at removal.
I chose to drill the rivets at the perimeter out then drill & tap the holes for re assembly. No nuts to loosen and looks kinda 'tough'.
These duo tone horn is part of the MGB character.
B
Life's most persistent and urgent question is, "What are you doing for others?"
Edited 1 time(s). Last edit at 2018-04-21 03:26 PM by riley1489.
Mark and Anthony H helped me through my horn 'correction' as well. Not so daunting once you get in there.
On one of my horns I needed to replace a Lucar tang . I used a bolt rather than the brass rivet which broke at removal.
I chose to drill the rivets at the perimeter out then drill & tap the holes for re assembly. No nuts to loosen and looks kinda 'tough'.
These duo tone horn is part of the MGB character.
B
Life's most persistent and urgent question is, "What are you doing for others?"
Edited 1 time(s). Last edit at 2018-04-21 03:26 PM by riley1489.
Attachments:
BH_lucas9H rep.jpg 23.4 KB
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