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  1. Trailer Brakes
  2. Dexter
  3. Hydraulic Drum Brakes
  4. 10000 lbs Axle
  5. 12-1/4 x 4 Inch Drum
  6. 16 Inch Wheel
  7. 16-1/2 Inch Wheel
  8. 17 Inch Wheel
  9. 17-1/2 Inch Wheel
Dexter Hydraulic Trailer Brakes - Duo Servo - Self-Adjusting - Left/Right - 12-1/4" - 10K
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Dexter

Dexter Hydraulic Trailer Brakes - Duo Servo - Self-Adjusting - Left/Right - 12-1/4" - 10K

Part Number: 23-404-405
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$749.03
$729.03 after $20.00 Mail-In Rebate
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Dexter Hydraulic Trailer Brakes - Duo Servo - Self-Adjusting - Left/Right - 12-1/4" - 10K Standard Grade 23-404-405
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These brakes automatically adjust as you tow so you don't have to crawl around on the ground to do it manually. Dual-plunger cylinder offers great braking power. 12-1/4" x 4" Assemblies fit 16" or larger wheels. Made in the USA. Great Prices for the best trailer brakes from Dexter. Dexter Hydraulic Trailer Brakes - Duo Servo - Self-Adjusting - Left/Right - 12-1/4" - 10K part number 23-404-405 can be ordered online at etrailer.com or call 1-800-940-8924 for expert service.
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Dexter Trailer Brakes - 23-404-405

Highlights

  • Always Balanced Braking: Self-adjusting design keeps shoes properly aligned—no manual tweaks needed.
  • More Braking Power: Dual-plunger cylinder applies both shoes evenly for stronger, smoother stops.
  • Consistent, Quiet Operation: Bonded pads prevent rivet scraping and reduce noise as they wear.
  • Smoother Stops Over Time: Tapered pads minimize stutter and lockup while maintaining even contact.
  • Straightforward Replacement: Left and right assemblies fit 7-bolt flanges and 12-1/4" x 4" drums.
  • Built for Heavy Loads: Rated for 10,000-lb axles with 16" or larger wheels for confident braking.
Made in USA

Features to know about

Reliable Stopping Without the Guesswork: Self-Adjusting Duo-Servo Design

Dragging or uneven brakes can make towing unpredictable. These Dexter hydraulic brakes automatically adjust as you tow, so the shoes always stay in perfect contact with the drum. The dual-plunger cylinder applies both shoes evenly for stronger, more balanced braking than single-plunger setups. Each 12-1/4" x 4" assembly is rated for 10,000-lb axles and mounts with a 7-bolt flange, giving you consistent, confident control every time you stop.

Close-up image of Dexter hydraulic drum brake duo-servo plunger showing dual-plunger brake cylinder for even braking power on trailer brakes.

Smooth, Consistent Braking Every Trip: Bonded and Tapered Pads

Brake chatter or lockup often comes from worn or uneven pads. The bonded brake pads on these assemblies eliminate rivet holes for full friction contact and quieter operation. Tapered edges reduce stuttering and keep the braking feel smooth as the shoes wear down. It’s a small detail that makes a big difference in how steady your trailer stops feel mile after mile.

Close-up photo of Dexter drum brake showing bonded tapered brake pad designed for smooth, consistent trailer braking performance.

Less Time Under the Trailer: No Manual Adjustments Needed

If you’re used to crawling under your trailer every few trips to tweak the brake adjustment, this upgrade will save you time and hassle. A built-in tensioning cable keeps the shoes aligned automatically as they wear, maintaining peak braking power without any tools or guesswork. Just bolt them on, bleed your lines, and hit the road knowing your brakes will stay dialed in.

Built for Heavy Loads and Frequent Use: Strong Construction for 16" or Larger Wheels

These hydraulic drum brakes are designed to pair with most standard hub-and-drum assemblies, including Dexter and Lippert (LCI). With compatibility for 16", 16-1/2", 17", and 17-1/2" wheels and a 10,000-lb axle rating, they deliver dependable stopping power for heavy-duty towing setups. The result is a solid, repeatable brake feel that keeps performance consistent even under demanding conditions.

Specs

Application

  • Application: most standard hub-and-drum assemblies, including etrailer, Dexter, and Lippert (LCI)

Dimensions

  • Dimensions: 12-1/4" diameter x 4" wide
  • Mounting flange bolt pattern: 7 bolt

Wheel Compatibility

  • Wheel size: 16" or larger

Weight and Capacity

  • Axle rating: 10,000 lbs

Warranty

  • Limited warranty: 5-year

Note

The brakes will be very hot after doing this, so after every 10 stops you'll want to wait about 10 minutes to let the brakes cool off before continuing. If you don't, you might cook and crack the pad material.

Diagram-style image of Dexter self-adjusting hydraulic drum brake showing adjuster cable and internal components for consistent trailer braking.

K23-404-00 Dexter Hydraulic Drum Brake Assembly - Duo Servo - LH - Driver Side - 12-1/4" x 4" - Self-Adjusting - 10,000 lbs

K23-405-00 Dexter Hydraulic Drum Brake Assembly - Duo Servo - RH - Passenger Side - 12-1/4" x 4" - Self-Adjusting - 10,000 lbs





Video of Dexter Hydraulic Trailer Brakes - Duo Servo - Self-Adjusting - Left/Right - 12-1/4" - 10K
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Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.




Video Transcript for Feature Breakdown: Dexter Hydraulic Drum Brake Kit

Today we're going to take a look at the Dexter 12-1/4 inch self-adjusting hydraulic drum brake kit. This includes both the left- and right-hand drum brake assemblies for 10,000 pound axles. Now the hydraulic drum brake assemblies, they are designed for use with surge type trailer brake actuators. These assemblies happen to be a dual-server, which has the dual plunger design. And that will deliver the same amount of braking when driving either forward or in reverse. And these are self-adjusting brakes. And you can tell that by the cable that goes around the pulley, goes down to a lever, that automatically adjusts the adjustment gear there, to get you the right braking.

Now, self-adjusting brakes will automatically adjust to deliver optimum performance and braking power. And there's no need for manual brake adjustments. They automatically adjust themselves. And proper adjustment will lead to better brake efficiency and less wear on your tow vehicle brakes. Now this part will include both the left-hand driver side, right-hand passenger side brake assemblies. Now the mounting bolts, and the hardware to install them is all sold separately.

Dimensions on these assemblies is 12-1/4 inch diameter by four inches wide. And I'm going to show you where those measurements are. The 12-1/4 would be the diameter from this shoe over to this shoe. So if we put a ruler on, there's your 12-1/4 inch diameter. The width would be the width of the pad on the shoe.

So, if you look, there's your four inches. So, 12-1/4 by four inches. Now this does require a brake mounting flange bolt pattern of seven bolts. And this does require the use of 12-1/4 inch brake drums. It does use a wheel size of 15 inches and larger. And again, this is designed for axles rated at 10,000 pounds.

And the last thing I want to mention to you is about how to tell the left-hand and right-hand assembly difference. on a new brake assembly, there'll be a sticker that'll tell you that. But if that sticker wasn't there, easiest thing to do is look at the length of the pad on the brake shoe. On this one, you'll see the pad goes from here to here. And on this shoe, is from here to here. This is a shorter pad, this is the longer pad. The shorter pad is the primary shoe, that'll always face the front of the trailer, so that's telling it goes this way. That means it's the right-hand passenger side. And if you look at the other one, the same way. The pad is from here to here. This one's from all the from here to here. This is the primary, show goes to the front. So, again, this tells you that this is the left-hand driver's side. But that should do it for the review on the Dexter 12-1/4 inch self-adjusting hydraulic drum brake kit, with the left- and right-hand drum brake assemblies for 10,000 pound axles.

Customer Satisfaction Score:

Ratings & Reviews

4.8

92 reviews
5 Stars
(80)
4 Stars
(7)
3 Stars
(3)
2 Stars
(0)
1 Star
(2)
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by:
I recently upgraded my trailer from electric drum brakes to hydraulic drum brakes. I found the Dexter Hydraulic Drum Brake Kit to be very easy to install, and it works very well. I was able to install the kit myself, which saved me a lot of money. The kit is well made and includes everything you need for installation, including detailed instructions. I am very happy with the Dexter Hydraulic Drum Brake Kit.
by:
This was just what I needed. The staff at etrailer was over and above helpful, knowledgeable and efficient.
Byron profile picture

Byron

2/24/2020

Good

by:
Customer Service was GREAT! Help find the right product and shipping was fast.
by:
Quick reliable service parts ready to ship
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Should have ordered the ones that had the dust covers on the back
by:
I had some parts missing nuts/bearings and seals
by:
brakes arrived faster than expected. They were an exact fit for my dexter 8k tag axle on my 1998 Bounder Motorhome. The price was very fair compared to other venders
by:
Parts received exactly as were needed. Etrailer customer service ensured my companies needs were met and exceeded. Great job as always.
by:
After electric brakes this Hydraulic breaks works just super fine for moore then a one year electrical brakes i used to replace every 6 months!
by:
Good product, good availability, good price and great service. Is there any reason not to buy again from etrailers?
Much easier, faster and almost cheaper to buy the kit then replacing the separate Needed parts
by:
great price and fast shipping, had one box came in completely destroyed in shipping with parts missing, one call later and the new part came in the next day great company to work with for sure
by:
The order arrived quickly and was exactly what I needed.

The boxes with the hub were damaged and retaped. Some of the lug nuts were off the studs, but were all there.
by:
paid for the fast shipping. got my brakes on time! was what we needed to get the job done. Gwen answered all my question knew what i needed.
will order again when we need anything else for our trailers!
by:
Fast shipping. Great product selection. Called in for help finding the correct product and got a educated person helping me. Great company!!
by:
always super fast shipping and helpful staff
by:
Fast shipping, quality parts! Thank you! Looking forward to doing business in the future!
by:
They always have what I need, at a competitive price, fast shipping, very helpful on the phone finding what I’m looking for
by:
Excellent seller, fast shipping, thanks!!! A++++++
by:
Great place to shop for trailer parts
Always have what I need in stock
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See what our Experts say about this Dexter Trailer Brakes

  • What Is the Weight Capacity Of a Dexter D100G Axle
    The spoke with Dexter and the code "D100G" tells me you have two 10,000 lb trailer axles. I have attached some parts you may need for the axle below. Dexter Trailer Hub Drum Assembly (After July 2009) - part # 8-430-5UC3 Dexter Trailer Hub and Drum Assembly (Before July 2009) - part # K08-288-90 Dexter Electric Trailer Brake Kit (12-1/4" x 4") - part # 23-438-439 Dexter Hydraulic Drum Brake Kit (12-1/4" x 4") - part # 23-404-405 Inner Bearing - part # 387A Inner Race - part # 382A Outer...
    view full answer...
  • Converting Electric Brakes to Electric Over Hydraulic Tandem 10K Axles
    Thanks for letting us help Glen. To determine the correct brake assemblies for your trailer, we'll first need to confirm the dimensions of your existing brake drums: If you have 12-1/4" x 3-3/8" drums, you'll need the Dexter Hydraulic Drum Brake Assemblies # 23-410-411 If you have 12-1/4" x 4" drums you'll need # 23-404-405 If you can reply with the part number from your hub/drum or existing brake assembly, I should be able to confirm which set you need. Each set includes brakes for...
    view full answer...
  • Replacement Hub/Drum Assembly and Brakes for Dexter 10k Axle on Eager Beaver Deckover Trailer
    Hey Garrett! With a 387A outer bearing you may be able to use the # DX68QR you were looking at which uses the same 9-27 drum. Make sure the 387A was the outer, and not the inner bearing. Your inner bearing would be the 395S and then for the seal it is a 10-56 with an inner diameter of 3.125". I don't know of a pre-greased option with the bearings and seals installed for 10k hubs so this is the best we can offer. For brake assemblies you can use the Dexter Nev-R-Adjust Electric Trailer...
    view full answer...
  • Replacement Drum Brakes Assembly for 10,000 lb Dexter Axle
    We have drum brake assemblies for your 10K Dexter axles. If you want the electric assemblies, we have the Dexter Electric Brake Kit - Self-Adjusting - 12-1/4" - Left/Right Hand Assemblies - 9K to 10K # 23-450-451 if your hubs are 12-1/4 by 3-3/8 inches. If your hubs are the 4 inch width, then you will use the Dexter Electric Trailer Brake Kit # 23-438-439. If you have hydraulic brakes we have the following: # 23-410-411 for 12-1/4 x 3-3/8 inch drum # K23-524-00-2 for 12-1/4 x 3-1/2...
    view full answer...
  • Parts Needed to Convert Triple Axle Trailer with Drum Brakes to Electric Over Hydraulic
    You'd need a set of 10k rated hydraulic drum brakes like the part # 23-404-405 per axle and then also a kit with the EOH actuator and electronics like the Hydrastar # HS381-9066 and the brake line kit # HS496-253 and you'd have everything you need to convert your trailer with three 10k rated axles with drum brakes to electric over hydraulic drum brakes.
    view full answer...

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Info for this part was:

Employee Lindsey S
Edited by:
Lindsey S
Employee Jeff D
Installed by:
Jeff D
Employee Wilson B
Updated by:
Wilson B
Employee Hannah L
Updated by:
Hannah L
Employee Alexander C
Written by:
Alexander C

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