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Replacement Check Valve for Demco SBS Supplemental Braking Systems

Replacement Check Valve for Demco SBS Supplemental Braking Systems

Item # SM99909
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Replaces the check valve that came with your Demco SBS Air Force One (SM99202 or SM99243) or Stay-IN-Play Duo supplemental braking system (SM99251). Call 800-298-8924 to order Demco accessories and parts part number SM99909 or order online at etrailer.com. Free expert support on all Demco products. Guaranteed Lowest Price and Fastest Shipping for Replacement Check Valve for Demco SBS Supplemental Braking Systems. Accessories and Parts reviews from real customers.
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  • Reviews (5)
  • Q & A (5)
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Demco Accessories and Parts - SM99909

  • Tow Bar Braking Systems
  • Hardware
  • Demco

Replaces the check valve that came with your Demco SBS Air Force One (SM99202 or SM99243) or Stay-IN-Play Duo supplemental braking system (SM99251).


  • Replaces the check valve that came with your Demco SBS supplemental braking system
    • Works with Air Force One (SM99202 or SM99243) and Stay-IN-Play Duo (SM99251)
  • Check valve installs between the brake booster and the towed car's engine
  • Required on all towed cars that don't have a diesel engine and aren't Hummers
  • Includes 1 replacement check valve

16126 Demco SBS - (Formerly SMI) Replacement Check Valve for Air Force One or Stay-IN-Play Duo Supplemental Proportional Braking System

Replaces Demco SBS SM15601 and SM99909

Customer Reviews

Replacement Check Valve for Demco SBS Supplemental Braking Systems - SM99909

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

Replaces the check valve that came with your Demco SBS Air Force One (SM99202 or SM99243) or Stay-IN-Play Duo supplemental braking system (SM99251).

- SM99909

Exactly what I needed. Bought a used Invisi-Brake and needed a 3/8 check valve for the master cylinder. This part is perfect. Fast shipping and a great price!! 737413

- SM99909

replaced a bad check valve after five y ears. 704621

- SM99909

Came quickly and well priced 619707

Patrick C - 04/10/2020


- SM99909

Fast, as ordered, pleasure to do business with. 595787

- SM99909

Inexpensive item that should be replaced yearly for safety reasons. 583420


Ask the Experts about this Demco Accessories and Parts

  • Installation of SMI Replacement Check Valve on 2019 Ford Ranger
    The Replacement Check Valve for SMI Supplemental Braking Systems # SM99909 on your 2019 Ford Ranger will install in the either of those two hoses according to my tech contact at Demco (who owns SMI). He said you will install it only in whichever line you install the T-Fitting. The rubber hose will be easier for sure so that is my recommendation and the black side of the check valve needs to be on the engine side. I've attached a photo from the instruction manual of the SMI Stay-IN-Play...
    view full answer...
  • What are the Dimensions of SMI replacement Check Valve # SM99909
    I measured the Replacement Check Valve for SMI Supplemental Braking Systems # SM99909 for you. The overall diameter at the barbs for each end is 0.42 inches. The more narrow parts at the base have a diameter of 0.37 inches. The center, widest section is 0.76 inches in diameter. The overall length is 1.66 inches. This valve was designed to work with the Air Force One SM99202 or # SM99243 and Stay-IN-Play Duo # SM99251. So if you have one of these systems this is the correct replacement. If...
    view full answer...
  • Check Valve for SMI Supplemental Braking System on 2003 Jaguar X-Type
    The Replacement Check Valve # SM99909 that you referenced is designed for use with the SMI Stay-IN-Play DUO Braking System # SM99251 or the Air Force One # SM99243 and is needed on your Jaguar if you are installing either of these systems. The valve will indeed fit your vehicle. I have attached a couple diagrams taken from the installation instructions for these braking systems that you can take a look at as well.
    view full answer...
  • Recommended Replacement Components for SMI Air Force One on 2019 Ford Ranger
    You can use the 1/4" Air Line Hose - SMI Air Force One or Stay-In-Play Duo Supplemental Braking System # DM16114 sold in 1 foot increments, so if you need 6 feet of new hose you can simply select quantity 6 on that product page and you will receive one 6 foot section of hose. The compression fittings like the Replacement Female Push-On Hose Connector for SMI Air Force One Supplemental Braking System # SM99726, the Replacement 1/4" Female Pushlock Fitting for SMI Supplemental Braking...
    view full answer...
  • Troubleshooting SMI Air Force One Braking System Triggering Check Engine Light on Toyota Corolla
    I reached out to my contact at SMI (now Demco) and he said that on your 2017 Toyota Corolla iM the exhaust port on the Air Force One # SM99243 operating unit does need to be left open. He said the issue in your case is that the vacuum check valve between the tee and operating unit has likely failed. You can simply replace this vacuum check valve with part # SM99909 and face the black portion of the valve towards the unit, making sure to unplug the exhaust port in the process. This...
    view full answer...

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Info for this part was:

Expert Research:
Michael H
Written by:
Sarah W
Updated by:
Kristina F

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