If you're tackling an air force one braking system installation, you're probably looking for that seamless braking experience where your towed vehicle mirrors exactly what your motorhome is doing. It's one of those projects that looks a bit intimidating when you first crack open the box and see all the hoses, wires, and that little air tank, but once you get into the rhythm of it, it's actually a pretty logical setup. Most folks choose this system because they want a truly proportional brake—meaning if you tap the brakes on the coach, the car taps them too, and if you slam on them, the car does the same.
The beauty of this system is that it uses the existing air brake system from your diesel pusher to trigger the brakes on your car. It's elegant, but it does require a bit of "surgery" on both the motorhome and the vehicle you're planning to tow.
Getting the coach side ready
Before you even touch your car, you have to get the motorhome prepped. Since the system relies on the coach's air supply, you'll be installing a small "ping tank" and a control valve onto the motorhome's chassis. The real trick here is finding a good spot to mount that tank. You want it somewhere secure, usually back near the rear axle, where it's protected from road debris but still accessible if you ever need to check the fittings.
You're going to be tapping into the supply line and the metered side of your coach's air brakes. This is the part that makes some people a little nervous—cutting into the air lines of a massive motorhome isn't something you do every day. But as long as you have a sharp tube cutter and you make clean, square cuts, the push-to-connect fittings work like a charm. You just have to make sure you've drained the air tanks first; otherwise, you're going to get a very loud, very startling surprise when you make that first cut.
Once the tank is mounted and the lines are plumbed, you run a single air line to the back of the coach where the hitch is. This is where you'll mount the female quick-connect fitting. This is the "handshake" between the two vehicles.
Mounting the operating unit in the car
Now, let's talk about the car side of the air force one braking system installation. You've got this main operating unit—a black box that's about the size of a thick paperback book. You need to find a home for this under the hood. In modern cars, engine bays are cramped, so this can feel like a game of Tetris.
Ideally, you want to keep it away from extreme heat sources like the exhaust manifold, but close enough to the battery and the vacuum booster that you aren't running miles of hose. I've seen people tuck them behind headlights or mount them to the firewall. Wherever it goes, make sure it's bolted down tight. You don't want this thing rattling around when you hit a pothole in Nebraska.
The pedal actuator is the heart of it
The most critical part of the whole install, in my opinion, is the air cylinder that attaches to the brake pedal arm. This is what actually pulls the pedal down to stop the car. You have to mount an anchor to the firewall (or the floor, depending on the car's design) and then clamp the cylinder to the brake arm.
The alignment here has to be spot on. If the cable is pulling at a weird angle, you're going to wear out the seal on the cylinder or, worse, the cable could snap. You want a straight shot from the cylinder to the anchor. And here's a pro tip: leave a little bit of slack in the cable—about a quarter-inch of play. If it's too tight, your brakes might drag while you're cruising down the highway, and you definitely don't want to smell burning brake pads when you pull into a campground.
Dealing with the vacuum and air lines
Every car with power brakes has a vacuum booster. Since your car's engine isn't running while it's being towed, you don't have a natural vacuum to help with the braking. The Air Force One system handles this by "creating" a vacuum for the booster.
You'll be cutting into the car's vacuum line and installing a couple of check valves and a T-fitting. It sounds complicated, but it's mostly just making sure the valves are facing the right direction. If you put a check valve in backward, the system won't work, and you'll have a very stiff brake pedal. Just follow the arrows on the valves—they're there for a reason!
After the vacuum is sorted, you run the small air line from the operating unit under the hood, through the firewall, and into the cabin to connect to that cylinder on the brake pedal. This is often the most annoying part of the job—trying to find a hole in the firewall or poking a new one through a rubber grommet without nicking any factory wires.
The break-away safety system
We can't talk about an air force one braking system installation without mentioning the break-away kit. It's the "just in case" part of the setup. You mount a small switch on the front bumper of the car and connect it to a small air bottle or the main unit. A thin steel cable runs from this switch to the hitch of the motorhome.
If, by some freak accident, the car ever becomes uncoupled from the coach, that cable pulls a pin, and the car's brakes lock up immediately to stop it from rolling into traffic. It's one of those things you hope you never, ever see in action, but you'll sleep better knowing it's there. Wiring this up is usually just a couple of wires to the battery and the operating unit.
Testing and the "Light" check
Once everything is buttoned up, you've got to test it. Most people install a little LED light on the back of the car's rearview mirror or somewhere visible through the rear-view camera of the coach. This light is wired to the "cold" side of the brake switch. When the brake pedal in the car actually moves, the light turns on.
When you're sitting in the driver's seat of the motorhome and you push the brake, you should see that little light pop up on your camera screen. It's the ultimate reassurance. If you see that light, you know the air is flowing, the cylinder is pulling, and the car is doing its job.
Before you head out on your first trip, do a few low-speed stops in a parking lot. Listen for any air leaks and make sure the car isn't "pushing" the motorhome or braking so hard that it's jerking the hitch.
Maintenance and long-term use
The best thing about this system is that once it's in, there's almost zero daily setup. You just plug in the air hose between the coach and the car, clip on the break-away cable, and you're good to go.
However, it's a good idea to peek at the cable on the brake pedal actuator every few months. Cables can stretch a little over time, and you might need to snug it back up to keep that quarter-inch of play. Also, keep the quick-connect fittings clean. They usually come with dust caps—use them! Dirt and grit are the enemies of air seals, and a tiny bit of road grime can make those connectors a real pain to snap together.
At the end of the day, an air force one braking system installation is a solid afternoon's work, maybe a full day if you're taking your time and being meticulous (which you should be). It's a bit of an investment in time and money, but when you're coming down a steep mountain grade and you feel the car behind you perfectly mimicking your every move, you'll realize it was worth every penny and every minute spent under the dash. Ready to hit the road? Just double-check those air connections one last time and enjoy the ride.