Below are pics I took after separating the compressor from the horn of a Stebel Nautilus Compact Air Horn. It seems that alot of people who get these have them fail, and from what I have gathered, they fail due to weather, or due to the compressor coming loose from the horn. So I'm thinking if I go ahead and separate the compressor from the horn, mount the compressor under the body panels somewhere, mount the horn under the lights, then connect the two via hose superglued at both ends, hopefully this will last awhile.
There is a plastic shell covering the compressor and horn. Note the round part with the stebel logo, similar in shape to the round part on the other side. You need to be careful and save as much of the round part as possible (including the side), as this will be used (glued back on) covering and protecting one of the two diaphrams. You will need to cut (with a saw or dremel preferably) on the plastic shell. I cut down the center where the compressor is to start with, then cut back more from there. Unfortunately I don't really have any before pics, but it's easier to see where you need to cut if you can see what's underneath the plastic shell anyhow. The two pieces that wrap around the compressor have to be cut back some. Also, there is alot of glue (at least on mine) holding this all together. Take your time and remove as much of the glue as possible. Use a regular screwdriver to pry (but not too forcefully) and you'll eventually get it apart.
The big round piece with the stebel graphics you want to keep as intact as possible, including the sides. This will cover and protect one of the diaphrams.
Stock diaphram cover on the back side.
Side view. You can see that I could have saved a little more of the front diaphram cover. Be careful here.
Side view of the stock back side diaphram cover.
Side view of the diaphram cover cut from the covering plastic.
Side view showing where the compressor outlet plugs into the horn inlet. A 5/16" double ended barb fitting will go here.
The compressor, showing the minimal mounting bracket and the compressor outlet.
Another view of the compressor showing the mounting bracket and compressor outlet.
This is the compressor air inlet. There is a built up plastic tube that runs down the compressor to keep moisture out. I will probably reattach the tube (if it is still intact). Possibly with the compressor behind the body panels it would not need the tube, but it wouldn't hurt either.
Pic showing how the compressor normally attaches to the horn.
Another pic showing how the compressor normally attaches to the horn.
Compressor sliding up and out of the horn inlet hole.
After separating, I have spray painted both the horn and the compressor with a good flat black primer and paint that works on plastic and metal.
For mounting I will use some hose clamps, and I have a brass double ended 5/16" barb fitting to be superglued into the horn, and some 5/16" ID vinyl tubing to connect the compressor to the horn. I found the fitting and vinyl tubing at Lowe's. More pics to come later of the mounting process ...