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Demco SBS Coach Air Kit for Air Force One Supplemental Braking System

Demco SBS Coach Air Kit for Air Force One Supplemental Braking System

Item # SM99627
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Demco Accessories and Parts - SM99627
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Half system replaces the necessary coach installation components for Demco SBS Air Force One supplemental braking system for motor homes with air brakes (SM99243 and SM99202). Call 800-298-8924 to order Demco accessories and parts part number SM99627 or order online at etrailer.com. Free expert support on all Demco products. Guaranteed Lowest Price and Fastest Shipping for Demco SBS Coach Air Kit for Air Force One Supplemental Braking 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

Half system replaces the necessary coach installation components for Demco SBS Air Force One supplemental braking system for motor homes with air brakes (SM99243 and SM99202).


  • Replaces installation components for Demco SBS Air Force One supplemental braking system for motor homes with air brakes
    • Works with Air Force One system SM99243 (9599007) - sold separately
  • Half kit includes components for RV-side only
    • Vehicle-side kit (SM99209) sold separately

6231 Demco SBS - (Formerly SMI) Replacement Coach Installation Kit for Air Force One Supplemental Proportional Braking System

Replaces Demco SBS SM99627

Video of Demco SBS Coach Air Kit for Air Force One Supplemental Braking System

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

Video Transcript for SMI Air Force One Replacement Supplemental Braking System Installation - 2018 Tiffin Allegro Red Mot

Today, on our 2018 Tiffin Allegro red motor home, on our Freightliner chassis, you're going to be taking a look at, I'm going to show how I installed the replacement motor home insulation kit for SMI Airforce One supplemental braking system.Keep in mind, this setup is going to be a replacement kit for your RV side. Your car's already going to be setup. This is going to be if you purchase a new RV. You're going to need this to work with your car. Before we start the installation on the RV, I want to go over some of the parts that we're going to be installing. The main part is going to be this guy right here.

This is air tank. It's going to hold the air pressure, that's going to send air back to your towed vehicle. So when you apply the brakes, it applies the brakes on your towed vehicle.This is going to have three valves on it. You're going to have one here. You're going to have one here in the center and you're going to have one on the bottom.

These two are going to tie into the airlines on your RV. This one is going to tie into the L bracket we're going to mount on the back of the RV. Then it's going to be sending the air into your towed vehicle. You're going to get some airline tube, so you can run all of your lines. You're going to get T fittings.

These are going to mount onto your factory airlines on your RV. This is going to supply this with the air coming from the RV. And this is your L bracket and fitting that's going to be mounted on the back of your RV wherever you choose to mount it. I would suggest picking up a little bit of extra airline tube. So you make sure you have enough to run all of your fittings to where they need to go.

You can find that here at etrailer.com.First thing you need to do to start your installation, is you need to find a location to mount your air tank. Now on the 2018 Tiffin, there's not a whole lot of room on the underneath side to mount it, which is normally where we mount it. So what I did is this frame rail right here, I just drilled a few holes all the way through. See the three there And put a nut and bolt, flat washer, lock washer on it to hold it in place. I will say the hardware that comes with the tank, it's not long enough to go with this through here. So you will have to pick up a little bit extra longer bolts. Other than that, it's very solid. It's not going to go anywhere. Wherever you choose to mount it, you just want to make sure it's not going to be around a whole lot of heat. We're far enough away from our exhaust, which runs right here on the bottom. That it's not going to affect it any. And then same goes for our lines. I just ran through this existing zip tie here on this wire loom towards the rear axle on the vehicle.You're going to have three lines that are going to come out of it. Bottom one is going to go to your air fitting on the back of the motor home. This one here's going to be our metered airline. This one, which actually you can't see it, but it's on the other side of the tank. It's going to look like this. It's going to come straight out though. That's going to be your supply line. So what I did is I put both of these in and I just marked one of them a certain color. Like I marked my metered airline on the end of it, that's running up to my axle. I marked it with a yellow marker, yellow paint marker. So I can tell them apart because I'm running them to the same place.Again our other line down here on the bottom, just going to run back to an air fitting. That's going to be mounted right back here. Now you can mount this any place. It's going to come with nuts and bolts and washers. Most of your motor homes are going to be fiberglass on the back. So just make sure when you drill it, you take this bracket here because it's going to come assembled like this. Set it up there, take a marker and just touch the holes and then you'll have your holes to drill out or you'll have your marks to drill your holes. Run your nuts and bolts in there and you're good to go.Run your line, make sure your lines that are going into any of your fittings, even the ones on your tank that are flat cut. You don't have them cut at an angle and there's no kinks in them. Next you're going to run your two lines up to your rear axle. You can see I zip tied to this piece of loom here. And instead of running this way, same way as my exhaust. I went over top of my frame. I want to try and keep that away from my exhaust as much as possible. So you can see I followed my existing line here. Just followed this wiring over top of this, went up and through where all of my line is running through here. That's a cross brace on the frame.Over top of my bag. And then from our bag, I went up over top of this bracket here. Then we need to find our supply line and our metered airline. Your metered airline, if you can see here, this is the fitting for it right here. The metered airline is going to run on this particular chassis from here or from this one, this lower one to this one. There's just going to be a line that runs in between them. As far as the fitting, this is a brass fitting. You're just going to cut your line and then insert your metered airline. However you mark it, if you mark your metered air, you mark your supply line. Just make sure you're putting the right one in.One thing I do suggest, is before you cut any lines, you need to let all the air out of your brakes. And how you do that is just press on your brakes until there's no more air in your tanks. If you don't, what's going to happen when you cut your supply line, which is our big larger green one up there. You're going to get a big burst of air that's going to come out and it's going to come out hard. So you don't want to do that. Anyway, for our supply line, how you can tell if it's your supply line is before you cut it, if you just take one end out and they're just press fittings. So you can kind of see how that is. What you'll do is, you'll pull on this. You'll push that down. Push your line in and pull out.Before you add the fitting or doing any cutting of the line, pull it out of the existing spot that it is. Have somebody get in and push on the brake and hold your finger over the end of it. And if you're getting air pressure out of it, then you know you have the right one. Once you have that, you're going to go ahead and cut this line and fit your brass fitting in place. Make sure your two ends are inserted in all the way, so they don't leak. As far as our supply line, the supply line on the Freightliner is normally the very big, green line. Which you can see where that one is there. This is the line, you can see how big it is. It's usually going to be the biggest green line on there.You're going to do that one the same way, except like I said you want to make sure you empty the air out before you cut that line. You're not going to have to take this off this side. All you're going to do is you're going to cut it. You're going to put your fitting in, make sure it's seeded in very well so it doesn't leak. Then you're going to take your line running from the tank on the back into your large green line or your supply line. Once you've done that, then I suggest starting the vehicle. Let your tanks fill back up with air. Spray some soapy water on your fittings to make sure you're not getting any air bubbles. If you're getting air bubbles, make any adjustment needed to make sure that that line is seeded in there very well.That'll do it for a look at and installation on the replacement motor home insulation kit for SMI Airforce One supplemental braking system on our 2018 Tiffin Allegro red motor home.

Customer Reviews

Demco SBS Coach Air Kit for Air Force One Supplemental Braking System - SM99627

Average Customer Rating:  4.8 out of 5 stars   (12 Customer Reviews)

Half system replaces the necessary coach installation components for Demco SBS Air Force One supplemental braking system for motor homes with air brakes (SM99243 and SM99202).

- SM99627

Would have been 5 stars, but no instructions. We'll have to find them on the web. Etrailer price pledge saved $30. 498797

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.
-- Mike L - 04/21/2018


- SM99627

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. 649364

- SM99627

The order process and information was excellent. I just hope I can install all of this stuff I bought. I’ll let you know how it goes, hopefully within a few weeks.... 600055

- SM99627

Best braking system and easy install 599320

- SM99627

Product arrived when promised and has been installed. So far it seems to be maintaining air pressure but have not yet tested it while traveling and towing the Jeep. It replaces the part that worked well for ten years so should be good. 577988

- SM99627

Just what I need to finish my nstallation. The Blue Ox was given to me by the guy I bought the coach from but it was in multiple pieces cause his brother had given it to him. I guess he left the tank on his old coach so this was all I needed to make it work. Thanks for sending it so quickly! 504020

- SM99627

I received the product quickly and the product was every thing they said it was. Installation was easy and the brake system works great. 479619

- SM99627

Product was 3 weeks late shipping as factory supplier delayed providing product but I was kept informed all the time and when shipped was delivered within 3 days. Very pleased with the service. 478550

- SM99627

Always good prices. excellent customer service on the phone. item delivered as promised. 469576

- SM99627

Excellent comumication and service 444215

Working great
Mike R - 10/19/2018


- SM99627

Looks like a decent product as i havent installed. Howver no instructions for install in box. But I found instructions on smi web psge. 332448

- SM99627

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. 322819


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Info for this part was:

Test Fit:
Joe V
Test Fit:
Randy B
Test Fit:
Shane H
Expert Research:
Jameson C
Expert Research:
Jeffrey L
Video by:
Kathleen M
Video by:
Zach D
Video by:
Michael B
Written by:
Laura H
Video Edited:
Chris R
Updated by:
Sarah W
Updated by:
Kristina F

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