Boy, this was a LOT of work, but I finally got my train horns installed.
I had to wait for the weather to break and we've not had many good weekends in this part of the country. That said, the install took much longer than I anticipated.
My original Hadley's are mounted with a bolt through the top on the outside, and another nut/washer that is attached to the air nipple on the bottom side of the roof. This as it turns out, is almost impossible to access once the motorhome is built. It is between the fiberglass roof cap and the headliner. In my unit, you cannot remove the headliner without removing all the overhead cabinets in the front and perhaps even not then. It appears that the roof sits on top of the headliner, but it's hard to tell. What I finally had to do was remove one of my front stereo speakers and reach through the hole. Still the hole was not big enough and the angle was not there for me to be able to stick my arm inside to reach the bolt. I DID manage to finally get a pair of vice grips connected to the bolt, then had to go on the roof and unscrew the horns from the top.
Long story short, after losing my vice grips in the ceiling and breaking the air line, I installed the new horns on the roof, sealed up everything and quit for the weekend.
On Friday, I restarted the project. This involved pushing new air line down from the roof into the ceiling area. Then, I managed to grab the end of the new air line with my awning rod and drew it to the speaker hole. Then, I took the existing air line, cut that clean and installed a coupler and clamps. I buttoned everything down and really wanted to test it, but sitting in my neighborhood would NOT have been a good idea. I started the motorhome and gave the horn just a tap. I heard a peep from the roof, so I knew everything was connected. I was worried that the existing air line would not be big enough. The horns require a larger line than the Hadley's (which was a 1/4"). I figured worse case, I'd have to just replace the entire line which would not have been that difficult compared to what I'd already been through. Incidentally, I used my existing air solenoid and not the one provided by the horn manufacturer.
So....later that evening I took her for a drive. I waited until I was on the interstate ramp and nobody was really around for the test. I layed down on the horn and for a moment, silence. Then, the most gawdawful horn sound you've ever heard. Holy crap, pass the Tylenol
. These things are LOUD! My little beagle stared at me like "what the heck was that"?
Okay, I'm happy. They ARE loud, and it DOES sound just like a train. And they look pretty cool too.