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Dexter Hydraulic Drum Brake Assembly - Uni-Servo - 7" - Right Hand - 2,500 lbs

Dexter Hydraulic Drum Brake Assembly - Uni-Servo - 7" - Right Hand - 2,500 lbs

Item # 23-399
Our Price: $102.62
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Dexter Trailer Brakes - 23-399
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7" x 1-3/4" Passenger's-side hydraulic trailer brake assembly features a single-plunger design. Mounting flange has 4-bolt pattern. Fits 10" to 13" wheels. 1-800-940-8924 to order Dexter accessories and parts part number 23-399 or order online at Free expert support on all Dexter products. Great prices and Fastest Shipping for Dexter Hydraulic Drum Brake Assembly - Uni-Servo - 7" - Right Hand - 2,500 lbs. Accessories and Parts reviews from real customers.
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  • Reviews (19)
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  • Videos (1)
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Dexter Accessories and Parts - 23-399

  • Trailer Brakes
  • Hydraulic Drum Brakes
  • Brake Assembly
  • 7 x 1-3/4 Inch Drum
  • Dexter
  • RH
  • 2500 lbs
  • Single Servo

7" x 1-3/4" Passenger's-side hydraulic trailer brake assembly features a single-plunger design. Mounting flange has 4-bolt pattern. Fits 10" to 13" wheels.


  • Hydraulic drum brake assembly is designed for use with a surge-type trailer brake actuator
  • Periodic manual adjustment required
  • Adjuster plug (included) covers access hole to keep dirt and grime out of the assemblies and off of the shoes
  • Mounting bolts and hardware included
  • Made in the USA


  • Application: most standard hub-and-drum assemblies, including Dexter, Lippert (LCI), and AL-KO
  • Configuration: right hand (passenger's side)
  • Dimensions: 7" diameter x 1-3/4" wide
  • Mounting flange bolt pattern: 4 bolt
  • Wheel size: 10", 12", and 13"
  • Axle rating: up to 2,500 lbs
  • Limited 5-year warranty

K23-399-00 Dexter 7" Single Servo Hydraulic Brake Assembly - RH - 2.5K

Replaces 23-399

Video of Dexter Hydraulic Drum Brake Assembly - Uni-Servo - 7" - Right Hand - 2,500 lbs

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

Video Transcript for Dexter Axle Trailer Brakes 23-399 Review

Today, we're going to take a look at the Dexter 7-inch, right-hand passenger side uni-servo hydraulic trailer brake assembly for 2,500 pound axles. Now, this hydraulic drum brake assembly is a uni-servo design, which is used on trailers with surge-type trailer brake actuators. A uni-servo means it's a single plunger design. This design allows about 20% braking in reverse. The size on this assembly is 7-inches by 1 3/4-inches. This one is a passenger side trailer brake assembly.

The size, where they get that size from, is the 7-inches would be the diameter from this shoe to this shoe. If we put a ruler on it, there's your 7-inches. The 1 3/4-inch size is the width of the pad on the shoe, 1 3/4-inches. Again, this is the right-hand passenger side. The way you can tell that, now on all new assemblies it'll have a sticker that'll say right-hand side.

If the sticker wasn't there, the easiest way to tell is look at the size of the pad on the brake shoe. This pad goes from here to here. This one's from here all the way to here, so this is a longer pad, this is a shorter pad. Shorter pad is your primary shoe and that'll always face the front of the trailer, so that'll tell you that this goes on the passenger side. These brake shoes are aligned with an automotive grade friction material. It is fully bonded, it's not riveted inaudible 00:01:13 for a longer life, more braking torque.

It does require period manual adjustments, right down here is your adjustment gear. The backing plate has a nice e-coating 00:01:23 on it for excellent corrosion resistance. This does include the adjuster plug down here. When you go to adjust your brakes, you pop that plug out and put your adjustment tool in there to adjust it. Then you put this plug back in.

The plug is needed because it helps keep dirt from getting into your brake assembly. This does use 7-inch drums. Does include the mounting hardware, the four nuts right here that you install this with. This assembly is certified by USSA standards and the Canadian CSA standards. That should do it for the review on the Dexter 7-inch, right-hand passenger side uni-servo hydraulic trailer brake assembly for 2,500 pound axles.

Customer Satisfaction Score:

Customer Reviews

Dexter Hydraulic Drum Brake Assembly - Uni-Servo - 7" - Right Hand - 2,500 lbs - 23-399

Average Customer Rating:  4.9 out of 5 stars   (19 Customer Reviews)

7" x 1-3/4" Passenger's-side hydraulic trailer brake assembly features a single-plunger design. Mounting flange has 4-bolt pattern. Fits 10" to 13" wheels.


Purchased complete backing plate, shoes, cylinder, and hardware as a single assembled unit for both sides of trailer. They fit my Jayco trailer, with Dexter axle, perfect. The shoe mounting and return springs are the same as car drum brakes. The original Atwood spring system is very inferior to this replacement unit. Parts were delivered fast and worked perfect. As always, I can count on this Companies great parts and service. Thanks, Ken, from snowy Minnesota.


Installed easily, quality was good. Doesn't come with the stud nuts, glad I could reuse the old ones. Also doesn't come with new adjustment hole plug. These are standard parts with auto brake assembly kits. I would buy this again.


Drum brake assembly is exactly what I needed to replace some old and really worn brakes on a 1982 tent trailer. I was a bit skeptical as to if they would fit as there is no OEM parts out there but it turns out these were perfect!!


I ordered a brake assembly for my dexter axle. It was a perfect match. The shipment was promised In two days and I received it in a day and a half. Thanks again


Easy direct bolt on installation. Great warranty service.


Perfect fit however it does not come with the adjustment plug. My old one was missing so now I have to try to find one locally. Other than that great communication from etrailer and fast shipping. Thank you.


Cheaper than everyone here in Canada, parts are the same ones sold here in Canada
New brakes for 30-foot long Houseboat trailer


Retro fit well on old trailer


Thanks so much for finding this part for me. I had looked everywhere.


Found what I needed, called in to verify. Quick shipping and most important, as described.


Complete, easy to install



Great !!


Worked just like OEM.





They were an exact fit! Perfect.



See what our Experts say about this Dexter Accessories and Parts

  • Can Dexter Hydraulic Drum Brakes be Used in Place of Atwood 7 x 1-3/4 Inch Brakes
    There should be no problem going with Dexter hydraulic drum brakes # 23-399 and # 23-398 in place of the Atwood brakes. You just have to make sure that you have the correct mounting pattern for the Dexter brakes. The Dexter brakes mount on a 4 bolt flange. The holes are 2-7/8 inches apart on center. The center hole is 1.64 inches in diameter. If this matches your flange then you can use the Dexter brakes.
    view full answer...
  • How To Determine Right and Left Side of Dexter Hydraulic Drum Brake Assemblies
    If you look at the wheel cylinder of the brake assemblies part # 23-399 and # 23-398 you'll see the letters L and R stamped on them. The R means right hand side and L means left. I attached a picture that points out the letter. Right side means passenger Left side means driver.
    view full answer...
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  • 7 x 1-3/4 Hydraulic Brake Assembly Replacement
    You can replace the Atwood hydraulic brake assembly with the Dexter hydraulic brake assembly as long as the mounting bolt pattern on the assembly matches. I went to the warehouse and measured the Right and left Dexter, 23-399 and 23-398, Hydraulic Brake Assemblies and they have a 2-7/8 inch on center four bolt pattern.
    view full answer...
  • Availability of Replacement Wheel Cylinder for Atwood Hydraulic Brakes
    As you probably noticed Atwood is no longer in the actuator and brake assembly business so any spare parts are becoming extremely difficult to find. We do not currently have any replacement wheel cylinders that would work with your existing Atwood assemblies. The Dexter RH Wheel Cylinder # 54-80-4 that you referenced would unfortunately not be compatible. The only option I can offer, and really your best solution, is to replace the brake assemblies themselves. Even though your current...
    view full answer...
  • Options to Add Brakes to Personal Watercraft Trailer
    The parts needed to add hydraulic surge drum or disc brakes to a trailer are covered in the two linked articles, one for drum brakes and one for discs. Among the parts needed is a surge coupler that will compress under the pressure of the trailer's forward momentum and push hydraulic fluid through the brakes lines to the drum or disc brakes. These articles will give you a good sense of the scope of the project and its cost. I linked our main page for surge couplers, both types, and your...
    view full answer...
  • Brake Line Kit Recommendation for Dexter Brake Assemblies 23-398 and 23-399
    Trailer brakes use the same thread size whether they are disc or drum. The Kodiak Hydraulic Brake Line Kit # 20TA-BLKIT that you referenced would work well with the Dexter drums # 23-398 and # 23-399.
    view full answer...
  • Can 7 Inch Hydraulic Trailer Brake Drums be Used with Electric Brakes
    The Dexter hubs for hydraulic brakes # 23-399 and # 23-398 indicate that they are for use with hydraulic brakes only so you would not use them with electric brakes. The inside surface where a brake magnet would stick (called the armature surface) is not the correct design for electric brakes. In order to go to electric brakes you would also need to change the hubs. To keep the same bolt pattern you can use hub # 8-173-16UC3. And then you would need brake assembly # 23-48 for the right...
    view full answer...
  • Hub and Drum and Bearing Kit to go with 7 x 1-3/4 Inch Hydraulic Brake Assembly 23-399
    I believe that in the question you are referring to the 1.64 measurement is on the brake mounting flange, # 4-34. The center hole of the brake assembly, # 23-399, is larger than this and that is normal so it doesn't sound like you have anything to worry about for that. The matching left hand brake assembly is # 23-398. For a hub and drum assembly you can use # 8-276-5 which has a 4 on 4 bolt pattern and you would use bearing kit # BK1-150. For a 5 on 4-1/2 bolt pattern you can use hub...
    view full answer...
  • Installing Hydraulic Trailer Brakes on a Kristi Utility Trailer
    There are two ways to go. Drum brakes and Disc brakes. To determine which assemblies will fit on your spindles we will need to know the inner and outer bearing and seal part numbers. We will also need the Brake Mounting Flange bolt pattern on the spindles and the bolt pattern and size of the wheels that are on your trailer. For the hydraulic actuator we will need the size of the trailer tongue where the actuator will mount. If you will get back to me with your choices and the needed information...
    view full answer...
  • Parts Needed to Change Hydraulic Trailer Brakes Over to Electric Brakes on a 1997 Jayco Tent Trailer
    You will need two of the 7 inch electric brake assemblies, one right hand, # 23-48, and one left hand, # 23-47. You will also need an appropriate length of 10 gauge wire, item # 10-2-1, for running the wires to the trailer connector at the trailer coupler. Next, you will need a trailer connector to match the wiring on your vehicle, or the wiring you will need to install on your vehicle, to activate the electric brakes. I would recommend the Pollak trailer connector, item # PK12706, for...
    view full answer...
  • Adding Brakes to Acme Car Dolly
    We don't offer parts specific for the Acme tow dolly, but we have the parts you'd need to add either electric or hydraulic drum brakes. I'm assuming your tow dolly doesn't currently have brakes, and that your current hubs use the # L44649 as the inner and outer wheel bearing. If that's the case, to add electric brakes, you'd need the following parts: # 8-257-5UC3-EZ hub drum for EZ lube spindle or # 8-257-5UC3 for standard spindles # 23-47 and # 23-48 electric brake assemblies # H20044...
    view full answer...
  • Brake Controller For 2018 VW Tiguan With Factory 4-Flat & Brakes For Trailer With 2,000 lb Axle
    We can get you set up to tow your jet ski trailer and add electric brakes, but let's go ahead and start with the brake controller for your 2018 VW Tiguan. Since the vehicle already has a factory 4-flat, you would just need to add the 7-way and wiring along with the controller. You are on point with the wiring of your VW being finicky - that's a really good way to put it. The issue is that the brake light wire on a Tiguan is often inaccessible, or can be in different locations, if it can...
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  • Aluminum Car Trailer Restoration and Replacement Brake Recommendations
    Thanks for the feedback, and I am glad that you are finding our website helpful! For your 1989 Trailex CT-7031 all aluminum trailer with the specifications that you provided there are three options for restoring or replacing the brakes for this trailer. The three options are similar to what you mentioned, and are: 1.Hydraulic Drum, which is the most cost effective. 2.Hydraulic Disc, which is more expensive, but provides better performance. 3.Electric drum, which is most cost effective...
    view full answer...
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