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Coach Air Kit for Demco Air Force One Flat Tow Brake System

Coach Air Kit for Demco Air Force One Flat Tow Brake System

Item # SM99627
Our Price: $384.06
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Add or replace the coach-side components of your Demco Air Force One supplemental braking system. Includes all the needed parts and hardware on the motorhome side with no extras. 1-800-940-8924 to order Demco accessories and parts part number SM99627 or order online at Free expert support on all Demco products. Great prices and Fastest Shipping for Coach Air Kit for Demco Air Force One Flat Tow Brake System. Accessories and Parts reviews from real customers.
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Demco Accessories and Parts - SM99627

  • Tow Bar Braking Systems
  • Second Vehicle Kit
  • Demco

Add or replace the coach-side components of your Demco Air Force One supplemental braking system. Includes all the needed parts and hardware on the motorhome side with no extras.


  • Replaces the RV-side components of your Demco Air Force One braking system
  • Includes components for motorhome-side only

6231 Replacement Demco SBS Coach Installation Kit for Air Force 1 Supplemental Braking System - Proportional

Replaces Demco SBS SM99627

Replaces Demco SBS SM99251


Video of Coach Air Kit for Demco Air Force One Flat Tow Brake System

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.

Video Transcript for Demco SBS Air Force One Coach Air Kit Installation - 2019 Tiffin Allegro Red Motorhome

Hey everybody, Ryan here at etrailer. Today on our 2019 Tiffin Allegro Red motorhome, we're gonna be showing you how to install the Air Force One supplemental braking system just for the coach side. But before we do that, why don't we check it out and make sure this is a kit that's gonna be right for you. Before we get too carried away talking about the braking system and kind of checking all that out. I figured it'd be beneficial to just spend a minute or two and refresh ourselves on the main things that we're gonna need to flat tow our vehicle down the road in the first place. There's gonna be a total of five main parts that you're gonna need.

Now the first one is going to be the base plate and that's gonna provide us with a solid and reliable attachment point. That way we can hook our tow bar up to it. And the tow bar is gonna be the second component. That's gonna be the physical link that actually connects the front of your vehicle to the back of your motorhome. The third main component is going to be safety cables.

And these are just there in the event of an unlikely disconnect. They're gonna keep everything paired together. The fourth main component is going to be tow bar wiring. And what this is gonna do is transfer the lighting functions from the back of your motorhome, to the back of your Chevy keeping you safe and legal. And last but not least the fifth main part will be a supplemental braking system.

And what this is gonna do is apply the brakes in your Colorado whenever you hit the brakes in your RV, helping to bring you to a more predictable and complete stop. There are a couple more parts that aren't absolutely necessary but I definitely like to recommend just to give you a good experience overall. And one of 'em is what's called a battery charge line. And what that's gonna do is essentially maintain or trickle charge your truck's battery whenever you're flat towing it behind your motorhome. That way, you know, it won't be drained from the braking system.

A lot of times the supplemental braking systems are gonna use your truck's battery power. So what happens over time, you know, they keep using power and power and power and you just run outta juice. And so that's where that charge line is gonna come into play. It's gonna keep your battery full, that way when you get to where you're going you'll hit the key and everything will start up. And the other thing that I suggest for the Colorado is what's called the automatic battery disconnect. And I always recommend this for these trucks because with these, whenever you flat tow 'em, you have to disconnect the battery. And so that really leaves you a couple of choices. One of 'em being to pop the hood undo the battery, whenever you're flat towing it, hook it back up whenever you're ready to start your truck. And I mean, is it doable Sure. It'd probably get annoying over time. And that's where something like this would come into play. Alright, so, instead of having to deal with all that you simply just push the button, it disconnects the battery. Whenever you're ready to start the truck, push it again, power comes on and you're ready to roll. With this kit being the parts just for the motorhome side, this is probably only going to interest a small group of people with a very particular set of needs. But the good news is, if you fall into this category there's gonna be an option for you. So with that said, you know, there's a couple scenarios where this would come into play. One of 'em being, let's say if you already have, or are familiar with the Demco Air Force One braking system, you like the way it works, you know, it's reliable. And let's say you end up upgrading motorhomes, right You get a new motorhome. You know, is it really worthwhile to go underneath and rip all them parts off and put 'em on your new motorhome Some of you may say yes, a lot of people probably aren't gonna want to have to deal with it. So there's an option instead of getting the whole kit when you don't really need the whole kit, you can get just the motorhome side. Gets you squared away, your old vehicle already is set up to be flat towed, so you can just hook everything back up and get the show on the road. Another thing, or another reason some of you may want this kit is maybe the original one got damaged in some way. Maybe it was improperly installed. Something happened along those lines. You know, it's rare but, you know, stuff does like that happen. You get a ton of miles out on the road, weird things can happen, right Or maybe if, you know, you get a new motorhome and you still got the old one but you want to tow with your new one. This will, this will kind of translate over to that as well. So there's a bunch of scenarios that this can be used in, probably the most popular though getting a new motor home and getting it set up and already being familiar with the vehicle side of things. So, you know, if that's what you're running into this is definitely a solution for you. So, one thing I do wanna mention as well if you actually need just the vehicle side there's also second vehicle kits available. Or if you need the whole package, you know, the side for the vehicle, the side for the motor home there's that kit available as well. So a lot of different solutions out there for all those different types of situations. But other than that, at the end of the day, I mean really not much to it. It'll have all the parts you need to get things going on your RV and be able to hook up to your tow vehicle and go out on the road and enjoy yourself. As far as getting this installed goes, it's really not too bad, nothing complicated per se. You know, it's not the most fun crawling underneath of a motorhome, but something you gotta do one time, then you're done, right So, as long you stay focused you should be in pretty good shape. But speaking of that, why don't we go ahead and get this installed together now. To begin our installation on our motorhome side, we're gonna be working essentially just in front of our rear axle and we have to get all the components and air lines and fittings installed. I wanna mention you don't have to have a lift to do this. We just get it up in the air so we can see what we're doing a little bit easier. And hopefully give you guys at home a better visual as well. But this is definitely doable on the ground, just be a little bit tighter. Underneath the motorhome, we are just in front of our rear axle. And the first thing that you need to do is find a good spot to mount up your tank. So it turns out, right here in this area, the perfect spot. It's close to our lines that we're gonna be teeing into and it's outta harm's way and everything else. And it turns out, there's actually a factory bracket here holding on this air valve. I just removed the two nuts off of that. And the bracket on our tank already has some slotted holes in it. And so this was able to just push right up in place and then I can simply tighten them nuts back down. And that's what's keeping it secure, this thing is not going anywhere. So once this thing is mounted, we're gonna have a total of three air lines that we need to hook up, alright And you're gonna have this one here which will be the supply line and you'll plug in a piece of air line tubing into the quick connect fitting. And I'll show you in a minute how to do that properly and how to cut it properly and everything else. But you'll have one plugged into there. And then this one will go to your metered air. And so you'll plug one into there and both of them lines are just gonna shoot up about a foot above us, that's where all of our main connections are. And then this one here, this is gonna go back to the fitting at the very back of our motorhome that we can hook up. And this is what's actually gonna give air to the vehicle side when we have it plugged in towing behind our motorhome. So, we'll get to this one in a minute. Let's focus on the supply, or I'm sorry the metered air and the supply line, like I said those are gonna go up maybe a foot or so and get plugged in to the main lines up top. So our supply line, what that's gonna mean is it's going to have constant air pressure all the time. And it's usually the thicker line. And in our case, it was, it's this thick green line. And so what you want to do with that is make sure all the air is depleted out of the system, because obviously if you cut that line with a hundred plus PSI in it, could get interesting. But you, to get the air out, you just hit the brakes a bunch with the engine off and eventually all the pressure will come out. But what you're gonna do is cut that line clean, take the included quick connect fitting, simply plug it in, and then obviously plug in the fitting or I'm sorry, the air line, into the other one that came off of our tank. Same exact deal with our metered air connection. So this is our metered air connection. And usually this is a smaller line but sometimes there'll be a couple of these. But with the metered air, what you're looking for, it's only gonna have air pressure when you hit the brakes. So, you can test it by putting, starting the motorhome up, you know, getting some air pressure into the system. And then you can unplug this line and have an assistant hit the brakes and then, when they hit the brakes, if air shoots out of this line then that's how you know that it's the metered air. But same concept, once you've figured that out, cut that line clean, put in your T and then plug in the line that comes from our new tank. And I wanna say too, with these lines, before you plug these quick connects in, make sure they're clean, take some rubbing alcohol or some brake cleaner or something like that and just wipe 'em clean because a lot of times you can have like undercoating and dirt and stuff on 'em and then cause a leak. So, make sure they're nice and clean, get 'em plugged in, and once this is done, we can route the remaining air line coming out of our tank all the way to the back of our motorhome. So now we're at the back of our motorhome. I ran our airline tube back here, and it's just so difficult to see underneath there but pretty straightforward, run this all the way back, do your best to avoid any hot or moving parts. And this is gonna get connected to this fitting. And this fitting here I just secured to our fiberglass here. It's pretty thick and I drilled a couple holes through it. Just used some nuts and bolts to get that secure. So I talked about how you want to cut these lines to plug 'em into the quick connect fittings. And so you wanna use a tool like this or a tubing cutter or a regular straight edge. And you want to cut it and inspect it. So you want this to be straight and clean. You don't want any, like, rough edges or burrs on it 'cause those can potentially cause a leak. So, don't use regular snips. Don't use your regular pair of Dykes or cutters to do this 'cause it'll pinch the air line and then you'll probably get a leak. So, you know, use something like this or some of the other tools I just suggested. But from there you're just going to simply just plug that right in. You'll feel it kind of snap into place and it'll lock in there and it'll be good to go. So now that we have everything hooked up, what I like to do, start the motorhome, fill it up full of air, check for any air leaks. So by checking, you can obviously listen or a better way is to take some soapy water, spray down where we're working. If you see any bubbles forming now you know you have a leak. If you don't, you know you're in good shape. If you do have a leak, drain the air, unplug the line. With these quick connects, you can kind of just hold the end of the connect with your finger and then pop the line out. So do that, recut the line, plug it in again and check it again until you verify that you don't have any leaks. And that'll finish up our look at and our installation of the Demco Air Force One supplemental braking system for the motorhome side only on our 2019 Tiffin Allegro Red..

Customer Satisfaction Score:

Customer Reviews

Coach Air Kit for Demco Air Force One Flat Tow Brake System - SM99627

Average Customer Rating:  4.9 out of 5 stars   (57 Customer Reviews)

Add or replace the coach-side components of your Demco Air Force One supplemental braking system. Includes all the needed parts and hardware on the motorhome side with no extras.


Simply to install. Great product. Thank you


Everything I needed to get my new coach to control the brakes on my tow vehicle!


Excellent service and support


Everything needed to get it installed. I installed it on an older air over hydraulic coach. Only required a longer airline as the connections we're made up front.


Great response and fast delivery


smi air brake for tow cars is the best brake system for a tow car and diesel pusher or class a motorhome with air brakes bare none ,once its installed all you do is hook up plug in and your off.I price checked multiple sources and etrailer had by far the best price.


Everything works great. Delivery up to Canada was not a problem. etrailer did themselves proud.


Thank you for sending the Air Force One supplemental braking system quickly. Placing the order was easy. I did appreciate the free shipping. In the near future, I will make an effort to check on any RV parts that your company has to offer.


i havent installed the part yet but i was amazed at how fast it was delivered


The new regulator on the tank did not come with information on which hoses to connect where, But I did find a etrailer online video that gave that information. The install went pretty fast.


I haven't installed the system yet, but I have given 5 stars for the OUTSTANDING customer service I received from etrailer. Shortly after I placed the order, I found the item listed for about $75 less on [another] store, and I submitted a claim under their 110% price guarantee policy. Even though the lower priced item had a fixed price and wasn't up for auction, I still didn't really expect etrailer to honor their pledge because the item was listed [online] Much to my surprise they honored their policy without question and credited the 110% my purchase almost immediately. The item was well packged and arrived quickly. I cannot recommend this company highly enough.


Bought another Allegro Bus that didn't have towing setup i had on my towable.
Was advised as to which kit to order, installer had no problems installing it. Everything went smoothly. Great service


I received the product quickly and the product was every thing they said it was. Installation was easy and the brake system works great.


I have used this system for several years and was fortunate to get a new RV, but it wasn't set up with supplemental braking. It was as easy to install as the first time and convenient that I did not have to buy the entire kit or piece it together myself. Easy from ordering to install. Thank you,


Would have been 5 stars, but no instructions. We'll have to find them on the web. Etrailer price pledge saved $30.

Etrailer Expert

Mike L.


If you click the provided link, you can see the installation instructions for the whole SMI Air Force One kit, the instructions specific for mounting the air system on the Coach begin on page # 8.


Received everything we needed to install on our coach. Instructions were very plain and easy to follow. This was my 2nd unit to install, I highly recommend these products, they are easy to install and they work very well.


Demco coach air kit was exactly as advertised and performs flawlessly


Just what I needed to switch my brake to my new coach.


Best braking system and easy install


It arrived sooner than expected. Have not installed yet.


Installed on my 2016 Meridian & works like a champ.


The kit was easy to install and works g reat.


Looks like a decent product as i havent installed. Howver no instructions for install in box. But I found instructions on smi web psge.


Always good prices. excellent customer service on the phone. item delivered as promised.


Excellent comumication and service

Mike R.


Working great

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