horn(s)

[SquareRoot]

I normally just blast some lube into them and then try honking a minute or two later.

That would get you arrested in my neck of the woods.

 

[Oldbear42]

is there a recommended soak time.?

I would recommend you wait 1/2 a can of beer (and not the first one on a hot day)...

 

[Oldbear42]

If the horn buzzes when hooked to power, you can fix it.

Horn off the truck, add 12V and a ground wire. While conected to power, tap the horn on the concrete. Horn will start to beep after a couple hits. Couple more hits it will get louder. Stop banging.

In my shop, we call that percussive maintenance.