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Lucas 9H Horn Repair

Posted: Thu Mar 14, 2024 1:19 pm
by svenedin
My Lucas 9H horn is not working properly and I have had to temporarily fit a modern replacement. It does not sound the same so I do not like the modern one.

I have watched a few videos on Youtube showing repairs on the 9H. It is very simple inside, a set of points, a coil and a diaphragm. It's basically like a speaker except for the points. Providing the coil is intact, it seems the most common fault is dirty points. Unfortunately, the unit was not meant for disassembly and the rivets have to be drilled out to get inside. It can of course be riveted back together with pop rivets.

I just wondered if anybody on here had repaired a 9H and how they got on with it? Was it a long term fix or did the horn fail again after a short time.

Stephen

Re: Lucas 9H Horn Repair

Posted: Thu Mar 14, 2024 9:06 pm
by Bill_qaz
Did you buy the high or low tone 9h replica

Re: Lucas 9H Horn Repair

Posted: Thu Mar 14, 2024 9:14 pm
by svenedin
I bought the horn that ESM offer which is Low tone. It doesn't claim to be a replica but it is very similar to a Lucas 9H.

The new horn is much louder than the old one, which is a good thing really (probably the old one was failing and I got used to it not being very loud) but it isn't the same note. I should have recorded the frequency of the old horn's note before it packed up.

Unfortunately, my old horn got thrown out. Not by me I might add!

I tracked down 2 more Lucas 9H low which work but not very well and the note is incorrect so I am considering taking one apart to refurbish it. The frequency should be 390-400 Hz (or cycles per second as the old manual states).

This is the workshop manual for adjustments. There is no manual that I can find for taking the unit to pieces but there are YouTube videos.

http://www.rjh-heritage.ch/index_htm_fi ... s%209H.pdf

Stephen

Re: Lucas 9H Horn Repair

Posted: Thu Mar 14, 2024 10:40 pm
by Bill_qaz
Have you asked moggy shed full with his clearance of parts?
Or you can find nos such as https://www.lmslichfieldltd.com/9H-Luca ... lt-Low-ton

Re: Lucas 9H Horn Repair

Posted: Thu Mar 14, 2024 10:47 pm
by svenedin
Bill,

Thank you for the link. I am amazed that new old stock horns still exist.

I looked at the listing and unfortunately the electrical connections are not the same. The one in the listing has only a single connection whereas my old horn had 2x connections. I know it looks like the one in the listing has 2x connections but that is actually the same terminal.

I will try to repair one of the ones that I have.

Stephen

Re: Lucas 9H Horn Repair

Posted: Fri Mar 15, 2024 10:59 am
by myoldjalopy
I once rigged a Morris Minor horn to the doorbell push. Didn't half make you jump when someone came to the door! :lol: