Awesome video! I literally had the exact same idea I have all the parts in my shopping cart to order. I added a set of add-a-leafs to my rancho springs and am adding the airbags as well so they are stiff and will level it and can handle a trailer better (or a motorcycle on a hitch carrier on the back).
They actually have a H3 specific airbag kit I found but essentially no different. I was going to use a dual purpose compressor (air ride and air tires) mounted where the factory muffler would be and plan on putting an air line connector on the side of the hitch like you did so I can use the same pump to adjust the air ride from in the cab and also use it to air up tires anytime it's needed!
So with your setup you can'[t adjust it without hooking the compressor to the fitting correct? Thinking about it really not that big of a deal as I'm not going to be needing on the fly adjustments so that may be an easier and cheaper option. Interested to see if they hold the 40psi more long term and how often you have to add air to it.
I have seen that there are H3 specific airbag kits, but I have never seen anyone run them before, so I went with this kit. I doubt that if I were to go with a H3 specific kit that it wouldn't be nearly as good as fit since I have the 4in Rancho lift kit and Extended shackles so that would throw off the suspension geometry that a standard H3 kit would be designed for. To answer your question, I can't adjust the amount of air pressure without having to use the valve on the trailer hitch. If I want to add air, I have to use an external air compressor to fill them up. I went ahead and bought a cheap 12V cigarette style air compressor, so I can easily just use the 12V cigarette lighter plug in the back of the H3. If I want to let air out of them, I need to push down on the valve just like if I am going to let air out of my tires. For me this really isn't a problem because I really don't need to adjust the air pressure every time I got for a drive, I just want the H3 to sit level. I know some people who drive street/performance cars like to air out the bags every time they park their car because they like their car to sit low for looks, but that's not something people really do in the offroad world. In the official firestone instructions you get with the kit, it specifies that you can expect to lose 3 – 4 psi per week and the air pressure needs to be checked at least in monthly intervals. I did leave my H3 sitting for over 2 weeks at 40 PSI without driving it at all and when I checked the air pressure again it was around 30PSI, so they do leak very slowly. Not that big of a deal though to fill them back up. If you know you aren't going to be going offroad anytime soon or you aren't going to be driving your H3, you could always compensate for the air loss by putting more air pressure in them. Say 50-60 PSI if your H3 is just gonna sit there for a few weeks.
