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Underbed Rail and Installation Kit for Demco Hijacker UMS 5th Wheel and Gooseneck Trailer Hitches

Underbed Rail and Installation Kit for Demco Hijacker UMS 5th Wheel and Gooseneck Trailer Hitches

Item # DM8551009
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Fifth Wheel Installation Kit

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Custom, underbed rail kit allows for uninhibited use of your truck bed once your hitch is removed. Works with Hijacker Underbed Mount Series (UMS) fifth-wheel and gooseneck hitches. No-drill frame brackets offer a simple installation. Call 800-298-1624 to order Demco fifth wheel installation kit part number DM8551009 or order online at etrailer.com. Free expert support on all Demco products. Guaranteed Lowest Price and Fastest Shipping for Underbed Rail and Installation Kit for Demco Hijacker UMS 5th Wheel and Gooseneck Trailer Hitches. Fifth Wheel Installation Kit reviews from real customers.
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  • Reviews (9)
  • Q & A (54)
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Demco Fifth Wheel Installation Kit - DM8551009

  • Below the Bed
  • Demco
  • Custom

Custom, underbed rail kit allows for uninhibited use of your truck bed once your hitch is removed. Works with Hijacker Underbed Mount Series (UMS) fifth-wheel and gooseneck hitches. No-drill frame brackets offer a simple installation.


  • Installation kit is designed for use with Demco Hijacker UMS 5th-wheel and gooseneck trailer hitches
  • Underbed rails allow for complete access to truck bed when hitch is removed
    • No exposed rails
    • 4 Mounting holes sit flush with truck bed
  • Vehicle-specific design reduces installation time and requires less drilling than universal systems
    • No-drill brackets bolt onto the outside of your truck's frame rails
    • Crossmembers sit along top of frame rails, beneath bed
  • Sturdy, black powder coated steel resists corrosion
  • Rails and installation hardware included
  • Made in the USA


  • Application: Demco Hijacker Underbed Mount Series (UMS) 5th-wheel and gooseneck trailer hitches
  • 5-Year limited warranty

8551009 Demco High Jacker UMS Under Bed Rail Frame Bracket Kit

Installation Details DM8551009 Installation instructions

This Product Fits The Following Vehicles

Customer Reviews

Underbed Rail and Installation Kit for Demco Hijacker UMS 5th Wheel and Gooseneck Trailer Hitches - DM8551009

Average Customer Rating:  3.7 out of 5 stars   (9 Customer Reviews)

Custom, underbed rail kit allows for uninhibited use of your truck bed once your hitch is removed. Works with Hijacker Underbed Mount Series (UMS) fifth-wheel and gooseneck hitches. No-drill frame brackets offer a simple installation.

- DM8551009
2017 Ford F-250 Super Duty

Easy in stall, Had my bed liner sprayed in and was afraid of scraping it taking out the hitch. Have had no problems so far even though I do it on my own. Its heavy but light enough for me to move to the back of the bed and take out with a floor hoist.

It did take work too install. The bed did have to be raised up but it wasnt a big deal. I do wish they had caps that fit better in the holes because the rails do sit flush with the bottom of teh bed. Rubber s moght be better to grip in.
kenneth r - 02/06/2021

- DM8551009

Good kit. All the parts were sturdy and well made. Took my truck in to a local installer and he completed the installation in about 1/2 of a day. You should be aware that the installation involves unbolting the truck bed from the frame and that makes DIY a major undertaking. Unless you have the tools, equipment and skills you should plan on using a professional installer. With this kit I can remove my hitch and the truck bed is open and uncluttered for every day use. Only evidence of the hitch are the four flush plastic caps on the bed.

- DM8551009

This rail system is certainly robust and I’m not concerned about it carrying the load of the fifth wheel at all. It is a quality product and seems to be made well. I installed this myself and it should be a relatively easy install; however, it was a huge pain. The rails install under the bed of my 2020 F-250 shortbed at the exact location where the truck frame has a bend in it. For this reason, the locking pins from the auto slide hitch above the bed couldn’t reach the under bed rail receiver holes (there was too much space since the frame rails slid down the bend in the frame). I couldn’t have installed this system by myself. With the help of a buddy, we were able to adjust the above bed hitch locking pins while one person was under the truck holding up the frame rails so they were snug with the bottom of the bed. This allowed the pins to properly drop into the frame rail receiver holes and lock the rails up against the bottom of the bed. In hindsight I could have held the rails in position by attaching them to the frame brackets first but that’s not how the instructions were laid out. This was my first fifth wheel hitch install so I guess I learned something to make my next install easier.

- DM8551009
2018 Ford F-350 Super Duty

Have this installed in my 18 F350 SRW and it works ok. Sometimes the latches bind when removing the hitch because it shifts slightly when towing. Installation was a pain. I had to remove all of the bolts holding the bed on, then raise the bed about 3" to get the rails in. Also, the rails sit directly up against the bottom of the bed so there's no way to install the hole covers when you have the hitch removed.

- DM8551009
2017 Ford F-350 Super Duty

Not so much the product, I'm sure it's great. But part number 60050 is apparently to similar the the part I received, part 6050. Paid extra for faster shipping on the original order. Because wrong parts were sent, we are returning it all. We had to locally source an entirely different hitch because we needed to install on a new truck that day. By locally sourcing, I mean drive 2 1/2 hours one way to get an above bed hitch and mounting system. Now I have a bunch of holes drilled in the bed of my truck that I didn't want and the customer service was horrible.

- DM8551009
Dodge Durango

2019 Durango 5th wheel hitch install kit for my customers new truck Always RV Mesa AZ

- DM8551009

The Delivery was missing parts. I called customers service they replaced and delivery next days .

- DM8551009

- DM8551009
2018 Ford F-350 Super Duty


Ask the Experts about this Demco Fifth Wheel Installation Kit

  • Will Bed of 2019 Ford F250 Need to Be Raised to Fit Demco DM8551009 Underbed Hitch Mounting Rails
    For your 2019 Ford F-250, Demco offers the Hijacker Autoslide in either an 18K version as part # DM8550022 or a 21K version as part # DM8550037. You'd also need the # DM8551009 under-bed rail kit. According to the installation instructions that I've linked for you, you won't need to completely remove the bed, but you will need to loosen the bolts that hold the bed on in order to slide the rails into place. This is especially true because you'll place the included vinyl sheets on top...
    view full answer...
  • Installing An Underbed Rail Installation Kit For Demco Hijacker UMS 5th Wheel And Gooseneck Trailer
    Yes, to install the Underbed Rail and Installation Kit for Demco Hijacker UMS 5th Wheel and Gooseneck Trailer Hitches Item # DM8551009 you will need to lift the bed approximately 2" to get the rails in between the frame and the bed.
    view full answer...
  • Under Bed 5th Wheel Rail Kit and AutoSlider Hitch Compatible with 2019 Ford F-350 Without OEM Pucks
    The Under-Bed Rail and Installation Kit for Reese Elite Series 5th Wheel Trailer Hitches #30068 was discontinued and is only compatible with commercial 34 inch frames, so it won't fit your 2019 Ford F-350. I reached out to Reese and they don't currently have a model compatible with the 2017-2019 model trucks. I do have an option for you that gives you the under bed rails and the automatic slider you are seeking, but you won't have the pucks like the factory option. I attached a photo...
    view full answer...
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  • Underbed Installation Rails for Fifth Wheel Hitch on 2017 Ford F-350
    There are a pair of underbed installation rails for your 2017 Ford F-350 Super Duty that does not have the factory prep package though nothing from Reese at this time. The Custom Underbed Installation Kit for B&W Companion # BWGNRK1116-5W doubles as a gooseneck hitch while allowing you the use of the Companion fifth wheel, either # BWRVK3400-5W for a sliding hitch if you have a 6-3/4' bed or # BWRVK3500-5W for a fixed hitch if you have an 8' bed. Your other option is from Demco, the...
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  • Underbed Fifth Wheel Hitch and Rail Kit Recommendation for 2017 Ford F-250
    We have the Demco underbed rail kits that fit your 2017 Ford F-250 like the part # DM8551009. With this kit installed you could use their 21k Demco hitch part # DM8550032 if you have a long bed or the auto slider part # DM8550022 if you have a short bed. The Demco hitches are USA made hitches that will work great for your application.
    view full answer...
  • Best Autosliding 5th Wheel Hitch for a 2020 Ford F-250 Super Duty
    The best autosliding 5th wheel hitch on the market is the Demco Hijacker which comes in a variety of options depending on what your 2020 Ford F-250 Super Duty is equipped with. If your Super Duty has the OEM Prep Package then we have the 18K # DM8550024 and the 21K # DM8550038 options which secure directly to the pucks in your bed. For a Super Duty that doesn't have the OEM Prep Package you can either use the 18K # DM8550034 or the 21K # DM8550035 with the above-bed rails # DM8552031-71...
    view full answer...
  • Sliding 5th Wheel Hitch With Underbed Rails for 2020 Ford F-350 Super Duty Towing Keystone Raptor
    There are two hitches that have an underbed rail system which fit your 2020 Ford F-350 Super Duty, and both have the capacity needed to tow a Keystone Raptor. I'll go over the options and make some comparisons so you are sure to get the right hitch. - Demco Hijacker Autoslide 5th Wheel Trailer Hitch with Slider # DM8550037 and Underbed Rail and Installation Kit for Demco Hijacker # DM8551009 - B&W Companion 5th Wheel Trailer Hitch with Slider # BWRVK3400-5W and Custom Underbed Installation...
    view full answer...
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  • How to Tell if 2018 Ford F-250 Has Puck System to use Demco Hijacker Autoslide
    While the best and most certain way to tell if your 2018 Ford F-250 has the puck system is to call your local Ford dealer with your VIN, it should be pretty easy to tell otherwise. If your bed looks like the accompanying photo - with four accessible holes (pucks) and a gooseneck in the middle - you have the puck system. You can also tell based on how your B&W Companion mounts. If you insert it into the pucks you have the B&W Companion OEM 5th Wheel Trailer Hitch with Slider for Ford...
    view full answer...
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  • Demco Hijacker Autoslide to Fit 2019 Ford F-350 with Factory 5th Wheel Prep Package
    The Demco Hijacker Autoslide fifth wheel hitch you asked about, part # DM8550022, actually fits into an aftermarket underbed kit, part # DM8551009. It doesn't fit the OEM puck system you have in your new 2019 Ford F-350. Instead you want part # DM8550024 that does fit right onto the pucks. It's basically the same hitch except for how it mounts into the truck. I've linked a video of it going into a 2014 F-350. It's the same puck system as what you have.
    view full answer...
  • Firestone Air Bags Compatibility With a 2019 Ford F-250 FX4 That Has Demco Underbed Rail System
    Yes, the Firestone Ride-Rite Air Helper Springs # F89ZR will work with your 2019 Ford F-250 FX4 and the Demco Underbed Rail and Installation Kit # DM8551009. The top air bag bracket mounts to the bottom of the frame rails so that there is no interference with the bracket on the side of your frame rail that the Demco kit uses. I recommend the Air Lift WirelessAIR Compressor System # AL74000EZ for supplying air to your air bags. This system allows you to adjust your air pressure from...
    view full answer...
  • Differences Between Above and Under Bed Fifth Wheel Hitch Mounts for 2020 Ford F350
    There are two ways to install a fifth wheel hitch on a pick up truck. One would be to use standard bed-mounted rails. Brackets are mounted to the truck frame with the bed rails sitting directly above. Holes are drilled down through the truck bed to correspond with holes in the brackets bolted to the frame, allowing the bed rails to be securely bolted down. The rails have slots in them that allow the hitch to be installed and removed pretty conveniently. The problem here is that once the...
    view full answer...
  • What is the Difference Between an Under-Bed and Above-Bed 5th Wheel Base Rail Kit 2018 Ford F-350
    In order to install the Demco Hijacker Autoslide 5th Wheel Trailer Hitch w/ Slider part # DM8550035 for above-bed base rail kits or part # DM8550037 for below-bed base rail kits on your 2018 Ford F-350 Super Duty you will need a set of 5th wheel base rails. We currently have two different sets of base rail kits for your truck; under-bed and above-bed. The above-bed base rail kit like the Demco Hijacker Premier Series Above-Bed Base Rails and Custom Installation Kit for 5th Wheel Hitches...
    view full answer...
  • Can Demco Hijacker Autoslide 5th Wheel Hitch be Used in Long Bed Truck
    While sliding fifth wheel hitches aren't necessary for long bed trucks, there is no reason you cannot use your existing Demco Hijacker Autoslide 5th Wheel Trailer Hitch # DM8550022 in your new 2017 Ford F-450. You will not have any issues when it comes to the sliding mechanism and travel of the hitch. If your F-450 does not have the factory rail kit, you can use the Demco Underbed Rail and Installation Kit # DM8551009. This kit is custom-fit for this truck and will allow you to mount...
    view full answer...
  • Best 5th Wheel Hitch for 2019 Ford F-250 With Short Bed
    Your 2019 Ford F-250 with a short bed is going to need a sliding fifth wheel hitch unless your fifth wheel trailer has a Sidewinder such as # RP34FR; otherwise a sliding hitch is necessary to ensure your trailer does not come into contact with your truck's cab and damaging it. The good news is there is one great option for a fifth wheel hitch that is going to make your towing experience with a short bed truck much easier because it won't require you to get out of your truck and activate...
    view full answer...
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  • 5th Wheel Trailer Hitches for a 2018 Ford F-250 4x4 Both with and without Factory Prep Package
    On your 2018 Ford F-250 4x4 look in the bed. If you see the 4 pucks in the bed like in the picture I have included then you do have the factory 5th wheel prep package. If you just see the indentations where the pucks would be then you do not have the prep package. If you do have those pucks then you can use a hitch that mounts directly in them. For a long bed truck you can use the following: # BWRVK3305 # C16036 # RP30871 # DM8550033 If you have the prep package and a short...
    view full answer...
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  • Underbed 5th Wheel Rail Mounting Systems for a 2017 Ford F-350 4WD With an 8 Foot Bed
    Yes, we do have some underbed mounting systems for your 2017 Ford F-350, but unfortunately there are no Reese 5th wheel hitch options rated for 26K. The only Reese hitch that fit with their Under-Bed Rail and Installation Kit # RP30126 was the Reese Elite 18K # RP30142. Neither of which are a fit for your F-350. If you were wanting to stick with the below bed rails we have an option from B&W which is their Underbed Gooseneck Hitch # BWGNRK1116-5W along with the Companion # BWRVK3500-5W...
    view full answer...
  • Under-Bed Fifth Wheel Rail Kit for 2017 Ford F-250 Super Duty
    The Reese Under-Bed Rail Kit # RP30073 that you referenced is designed for older model year Super Duty trucks and will not fit your 2017 Ford F-250. The under-bed kits we currently carry for your truck are the Demco # DM8551009 to be used with Demco fifth wheel hitches # DM8550032, # DM8550022, or # DM8550037 and the B&W # BWGNRK1116-5W to be used with the B&W Companion hitches # BWRVK3500-5W or # BWRVK3400-5W.
    view full answer...
  • How Much Can a 2019 Ford F-250 Crew Cab Powerstroke Tow
    The towing capacity of your 2019 Ford F-250 Crew Cab Powerstroke with the 6-3/4' bed will vary from 14,100-16,600 lbs depending on drive type, axle ratio, and gross combined weight rating. If you can provide me with this information I would be happy to provide you with an exact capacity. The axle ratio should be listed on a tag inside the glove box and the gross combined weight rating should be listed on a tag inside the driver door jamb but if not you can always call the dealer with your...
    view full answer...
  • Puck System Availability for a 2017 Ford F-250 Super Duty with a 6-3/4 Bed
    Although there are no 5 puck mounting systems available as of May 2018, we do have some underbed systems for your 2017 Ford F-250 Super Duty with a 6-3/4' bed. If the option to tow a gooseneck or 5th wheel trailer with a single underbed system is what you are looking for then the B&W Gooseneck Hitch # BWGNRK1116-5W is what you're needing. This system gives you a gooseneck hitch and hitch ball that is compatible with the B&W Companion Slider # BWRVK3400-5W which allows you to tow a 5th...
    view full answer...
  • Can Demco Gooseneck Adapter # DM5988 be Used with Underbed Demco Rails DM8551009
    Since you have a set of Underbed Demco Rails part # DM8551009 installed in your truck you can use the gooseneck adapter part # DM5988 that you referenced.
    view full answer...
  • Does Reese Underbed Rail Adapter Work With 2017 Ford F-350 That Does Not Have Prep Package?
    There are underbed fifth wheel rails that are going to work with your 2017 Ford F-350, though the Reese system # RP30126 is unfortunately not one of them. There is good news, however, because the Custom Underbed Installation Kit # BWGNRK1116-5W works on both the 6-3/4' and 8' four-wheel drive versions of the 2017 F-350; I've added a link to a video showing you these rails being installed in a '17 F-350. The biggest benefit of these rails are that they offer you a chance to use what is considered...
    view full answer...
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  • Recommended Fifth Wheel Hitch and Underbed Rails for 2017 Ford F-250 With Long Bed
    I'd be happy to help you when it comes to fifth wheel hitches. Essentially, to mount a fifth wheel hitch you need rails, and there are two types of rails: in-bed and underbed. The in-bed rails will be, as the name suggests, installed and exposed on top of your truck bed so you when you remove the fifth wheel hitch they would still be present. Underbed rails will be hidden and allow for complete bed access when your fifth wheel hitch is removed. Some trucks have an optional package that...
    view full answer...
  • Fifth Wheel Hitch for Aftermarket Underbed Rail System on 2017 Ford F-250 Long Bed
    Knowing what rail system you have on your 2017 Ford F-250 Super Duty is needed in order to get your truck a fifth wheel hitch. The reason is, aftermarket underbed rail systems are only fits for specific hitches and are not universal-type fits like above-bed rails, so what I can do is let you know the underbed rail systems that fit your 2017 Ford F-250 Super Duty long bed and you can compare them to see if this is one that you have. I made a photo for you showing the different kits that...
    view full answer...
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  • Is the Demco Hijacker Autoslide Compatible with a 5th Airborne Air Ride to Use on a 2017 Ford F-350
    The autosliding 5th wheel hitches are definitely the way to go with a truck bed that is under 8 feet, like your 2017 Ford F-350 with a 6-3/4 foot bed. I like to recommend them because they eliminate the need to get in and out of your truck when cornering. They also feature the single wraparound jaw for full 360-degree contact with the king pin and a 3/4 inch steel locking bar for added security. The cushioning that they provide helps to reduce chucking and jarring and the brackets on the...
    view full answer...
  • Recommended 5th Wheel In-Bed Wiring Kit for 2020 Ford F-350 Super Duty
    Glad to hear that you are already using the Demco 5th wheel towing setup, parts # DM8550032 and # DM8551009, for your 2020 Ford F-350 with the long bed. The wiring kit I recommend using is the Bargman # 50-97-410-010 because it uses a 90 degree turn from the 7-Way in your truck bed so you don't have to worry about stress on the wiring. This simply tees into your current wiring at the back of your OEM bumper 7-Way. I have attached an installation video of this on a 2017 F-350 that you...
    view full answer...
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Info for this part was:

Employee Mike L
Expert Research:
Mike L
Employee Jameson C
Expert Research:
Jameson C
Employee Lindsey S
Edited by:
Lindsey S
Employee Jeff D
Installed by:
Jeff D
Employee Amanda M
Written by:
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Employee Kristina F
Updated by:
Kristina F
Employee Noah M
Updated by:
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