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  1. Brake Actuator
  2. Demco
  3. Surge Brake Actuator
  4. Disc Brakes
  5. 2-5/16 Inch Ball Coupler
  6. 20000 lbs GTW
Demco Hydraulic Brake Actuator w/ Drop and Electric Lockout - Disc - Zinc - 2-5/16" Ball - 20K
Demco

Demco Hydraulic Brake Actuator w/ Drop and Electric Lockout - Disc - Zinc - 2-5/16" Ball - 20K

Part Number: DM8204311
In Stock
$573.05
Retail:$689.90
You Save: $116.85
Brake Actuator
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Heavy-duty and easy to use, this surge actuator engages your trailer's disc brakes and keeps them from locking up when you launch your boat. EZ-Latch coupler with a 4" drop keeps you from second guessing your connection. Made in the USA. 1-800-940-8924 to order Demco brake actuator part number DM8204311 or order online at etrailer.com. Free expert support on all Demco products. Great prices and Fastest Shipping for Demco Hydraulic Brake Actuator w/ Drop and Electric Lockout - Disc - Zinc - 2-5/16" Ball - 20K. Brake Actuator reviews from real customers.
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  • Reviews (143)
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Demco Brake Actuator - DM8204311

Highlights

  • No Brake Controller Needed: Surge design automatically applies disc brakes when you slow.
  • Back Up Without Brake Drag: Electric lockout stops brakes from engaging in reverse.
  • Quick, Confident Hookup: EZ-Latch drops onto a 2-5/16" ball and clicks firmly in place.
  • Ideal for Heavy Loads: 20,000 lbs GTW and 2,000 lbs tongue weight handle big trailers.
  • Great for Boat Use: Zinc plating with 200-hr salt-spray rating resists rust and corrosion.
  • Matches Tow Height Easily: Built-in 4" drop aligns trailer for level towing.
Made in USA

Features to know about

Confident Hookup Every Time: EZ-Latch Coupler with 4" Drop

The EZ-Latch coupler makes connecting to your hitch ball fast and sure. Just lower it onto your 2-5/16" ball and it locks automatically with a solid metallic click—no holding the latch back or guessing if it’s seated. The built-in 4" drop helps line up your trailer level without juggling extra hardware, and the low-profile handle resists bending or damage. The nylon composite latch is strong enough to take a beating and keeps working smoothly trip after trip.

Underside view of Demco EZ-Latch coupler with latch disengaged showing internal mechanism

Underside of Demco EZ-Latch coupler showing latch engaged around hitch ball socket

Cutaway view of Demco coupler showing internal latch and ball socket mechanism

Demco EZ-Latch coupler installed on straight-pole trailer tongue showing mounted configuration

Smooth Braking on Heavy Loads: Hydraulic Power for Disc Brakes

Built for serious towing, this surge actuator handles up to 20,000 lbs GTW and 2,000 lbs tongue weight. When you slow down, it compresses a heavy-duty aluminum master cylinder that sends hydraulic pressure to your disc brakes—no brake controller required. The large reservoir keeps plenty of fluid on hand, and the automotive-style diaphragm cap helps keep it clean by sealing out contaminants. Every stop feels steady and controlled, even under a full load.

Back Up Without Brake Drag: Built-In Electric Lockout

The electric reverse lockout ties into your trailer’s reverse light circuit so the brakes automatically disengage when you back up. That means no more manual pins or struggling up a ramp with the brakes fighting you. It’s a simple “set it and forget it” feature that makes maneuvering a boat or equipment trailer quick and frustration-free.

Backside of Demco surge brake actuator showing electric lockout solenoid and wiring connections

Long-Lasting Protection: Zinc Finish and Self-Lubricating Liner

This actuator is ready for years of use in harsh conditions. The zinc plating has a 200-hour salt spray rating to resist rust and corrosion inside and out—ideal for marine or utility setups. Inside, the actuator slides on a self-lubricating acetal copolymer liner that keeps movement smooth and wear low over time. Combined with its heavy-duty steel body, it delivers reliable performance season after season.

Close-up of hard plastic acetal copolymer lining inside Demco DA10 surge brake actuator

Straightforward Mounting: Bolt-On Design for 3" Tongue

Installation is simple thanks to the bolt-on design made for a straight 3" wide trailer tongue. It uses 1/2" x 4-1/2" Grade-5 bolts (not included) and follows a standard bolt pattern so setup goes quickly. With the included breakaway cable and tough construction, you get a secure connection from the first tow on.

Specs

Application

  • Application: trailers with hydraulic disc brakes
  • Designed to bolt on top of: 3" wide trailer tongue
  • Required bolts: 1/2" x 4-1/2" Grade-5 bolts (not included)
  • Bolt pattern: See below for bolt pattern dimensions

Demco surge brake actuator dimensional diagram showing 5-hole bolt pattern and mounting measurements

Weight and Capacity

  • Gross towing weight: 20,000 lbs
  • Maximum tongue weight: 2,000 lbs

Compatibility

  • Ball size: 2-5/16"

Mounting

  • Mounting: straight, 3" wide trailer tongue

Drop

  • Drop: 4"

Model and Warranty

  • Model number: DA20
  • Warranty: 1-Year warranty

8204311 Demco DA20 Hydraulic Trailer Brake Actuator for Disc Brakes - Electric Lock-Out - 2-5/16" Ball Easy-Latch Drop Coupler - 20,000 lbs

Installation Details DM8204311 Installation instructions



Customer Satisfaction Score:

Ratings & Reviews

4.6

143 reviews
Review sort icon
Heavy-duty and easy to use, this surge actuator engages your trailer's disc brakes and keeps them from locking up when you launch your boat. EZ-Latch coupler with a 4" drop keeps you from second guessing your connection. Made in the USA.

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THANK YOU FOR THE TIMELY SERVICE!!!



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Extremely Happy!



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Excellent service as always thanks Steve for all you help



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Well made unit at a price that was better than anything else I could find. Very easy swap from my older damaged unit.



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I love it works great.



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has worked out perfect so far 1 year la ter



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I cannot report on the functionality of the product as I have not yet installed it. But I can say that it appears to be a real good product, well packaged, arriving early, and in excellent condition.



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Works as it should. Perfect!

Harry H. profile picture

Harry H.

5/17/2022

Great



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Perfect fit for direct replacement on my boat trailer



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Great product support, great pricing, great shipping, value priced products. Long time customer and will continue forever!



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Perfect replacement could have provided instructions it would have made it idiot proof.



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Great fit and very easy to install. Customer Service is outstanding as well as sales (Lori). Highly recommend this company for all your trailer needs.



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Pros - Installation was very easy and bleeding was simple for 2 people

Cons - packaging was in a box more than twice the size of actuator allowing for a lot of obvious shifting with potential damage during transit. The new latch for the hitch is miss aligned from rest of hitch and has an apparent stress crack in it already. Not sure how long it will last compared to the steel ones on old model. It also has no place to lock the latch adding to theft concerns.



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Surge impulse actuator with electric lockout. This is to replace an older malfunctioning unit and in part the change was necessary to go from drum hydraulic to disc hydraulic brakes.



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Great product ,big up grade from what was on the trailer . Better stopping power for my Grady white . Great up dates on my order from etrailer. Com .



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Installed this on my boat trailer weighing in around 17,000 lbs total. ( boat and trailer) I have a long driveway with a slight incline and the electric lockout is terrible. While reversing the brakes would always engage and I would have to loosen the brake line with my flair wrench to complete my parking. I emailed e-trailer and they told me about the warranty process. It requires me to send in the faulty solenoid for them to inspect, and then deem if its covered or not. So I bit the bullet and just purchased another solenoid outright. Installed the solenoid and it worked fine with just the trailer, No boat on it. Once I loaded my boat onto the trailer, the brakes would lock as it did before. The solenoid was installed properly, to confirm this, I blocked both my truck and trailer tires. Put the truck in reverse and used a test light to verify 12v at the reverse light pin on my trailer light connection box.



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Have had the actuator for about a year now, has been perfect, zero issues.I do recommend pulling the floating pins a grease with some marine grease to help with removal if you ever need to service the actuator


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See what our Experts say about this Demco Brake Actuator

  • Does Demco Hydraulic Actuator part # DM8204311 Have Torque Specs
    The Demco Hydraulic Brake Actuator w/ Drop and Electric Lockout # DM8204311 does not have a torque spec listed for it. Instead you'd need to determine what the hardware you used torque specs are and go with that.
    view full answer...
  • Parts Needed to Convert to 7,000 lb Disc Trailer Brakes From Electric Brakes on Boat Trailer
    Hi Rick; thanks for the question and the info you provided, and the answer is yes, you can absolutely convert from electric brakes to disc brakes. Disc brakes give you the best overall stopping power, so it's something I definitely recommend. For a 7,000 lb axle and a 5-bolt mounting flange I highly recommend DeeMax brakes: - DeeMaxx Disc Brake Kit # DE53YR You'll need two of the # DE53YR for your tandem axle trailer, and the reason I like DeeMax is not only their superior rust resistance...
    view full answer...
  • How to Bleed Disc Brakes When Installing DA20 Demco Hydraulic Brake Actuator
    Attached is a clip from the instructions on how to bleed the brakes after installing the Demco Hydraulic Brake Actuator # DM8204311 that you referenced. You can use the Powerbuilt Brake Bleeder # ALL648591 to assist you in this process.
    view full answer...
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  • Recommended Replacements for Tie Down Engineering Model 20 Actuator
    If you're looking for a new coupler to replace a Tie Down Engineering Model 20, I recommend the Demco Hydraulic Brake Actuator part # DM8204311 which like the Model 20 has a 20,000 lb weight capacity designed for a 2-5/16" hitch ball. It uses a very similar mounting pattern so the install should be very easy. I have attached a photo below with the pattern so you can match up to your existing. I have also attached for you below a full list of our surge brake actuators which are suitable...
    view full answer...
    Image 1 for
  • Replacement for Model 20 Surge O Matic Brake Actuator
    Hey Chris! Do you need that full 20k capacity? Do you have disc or drum brakes? I recommend the following based on brake type: -Demco Hydraulic Brake Actuator w/ Drop - Drum - Zinc - 2-5/16" Ball - 20,000 lbs # DM8204011 -Demco Hydraulic Brake Actuator w/ Drop and Electric Lockout - Disc - Zinc - 2-5/16" Ball - 20K # DM8204311 Both are designed to fit a 3" wide tongue and use a 2-5/16" ball with the same capacity you have now. If a lower capacity will work let me know in the comments...
    view full answer...
  • How To Bleed Brakes Using Demco DA20 Hydraulic Brake Actuator
    I have attached for you below a photo which goes over the bleeding procedure for the Demco Hydraulic Brake Actuator part # DM8204311. I have also emailed you a copy of the installation instructions straight from Demco's site.
    view full answer...
    Image 1 for
  • Can Demco Disc Brake Actuator w/ Lockout & 20,000 lb Capacity Work w/ Drum Brakes
    Disc brake actuators like the Demco Hydraulic Brake Actuator w/ Drop and Electric Lockout - Disc - Zinc - 2-5/16" Ball - 20K # DM8204311 cannot be used with drum brakes because disc brake actuators use much higher pressure, so they could blow out the wheel cylinders, among other issues. That said, you can add a lockout to the drum brake version of this actuator: - Demco Hydraulic Brake Actuator w/ Drop - Drum - Zinc - 2-5/16" Ball - 20,000 lbs # DM8204011 - Reverse Lockout Solenoid for...
    view full answer...
  • Length of 20k Demco Hydraulic Brake Actuator DM8204311
    Yes I can; as you can see the mount portion measures 7 inches and the portion behind it measures 9-1/4 inches for the Demco disc brake actuator you asked about, which is the following part number: - Demco Hydraulic Brake Actuator w/ Drop and Electric Lockout - Disc - Zinc - 2-5/16" Ball - 20K # DM8204311
    view full answer...
    Image 1 for
  • Coupler Lock that Fits Demco Actuator part # DM8204311
    Yes, the Amplock hitch lock part # AMP34FR does work with the Demco Actuator part # DM8204311 that you referenced.
    view full answer...
  • Recommendation on a Surge Coupler that is Rated to Work on a Trailer w/ Disc Brakes
    I found a surge coupler that will work well on your trailer. However, the part that you referenced, # DM8204011, is designed only to work with drum brake systems. Disc brake systems need higher psi for the calipers to activate the brakes and drum surge coupler cannot supply the correct pressure. I recommend the Demco Hydraulic Brake Actuator w/ Drop for Disc Brakes, # DM8204311. This surge coupler is almost identical to the one you referenced, except it is rated to be used with disc brakes.
    view full answer...
  • Availability Of Hydraulic Brake Actuator With 12,500 lb Capacity
    We do offer several Hydraulic Brake Actuators with a 12,500 lb capacity like the Demco # DM8104311. This is made for trailers with disc brakes and it uses a 2-5/16" trailer ball. It will mount to a 3" trailer tongue. We do have options rated up to 20,000 lbs, like the Demco # DM8204311 if you need something stronger. If this is not exactly what you are looking for, feel free to reach out to me with more details and I am happy to help.
    view full answer...
  • Recommended Surge Brake Actuator For 17000lb Trailer
    To replace your current 16500lb actuator with a heavier duty option I recommend the Titan Brake Actuator - Painted - Drum - 2-5/16" Ball - Weld On - 20,000 lbs # T1521000 if your trailer has drum brakes, or the Demco Hydraulic Brake Actuator w/ Drop and Electric Lockout - Disc - Zinc - 2-5/16" Ball - 20K # DM8204311 if your trailer has disc brakes. Both of the options have a 20000lb towing capacity which is the next step up from the 16500lb actuator your currently have, and both will fit...
    view full answer...
  • Triple Axle Brake Line Kit for Use with Demco Surge Actuator part # DM8204311
    Yes the triple axle brake line kit part # HS496-253 is the correct brake line kit for your trailer with the Demco actuator part # DM8204311.
    view full answer...


Info for this part was:

Employee Leah B
Edited by:
Leah B
Employee Lindsey S
Written by:
Lindsey S
Employee Jeff D
Installed by:
Jeff D
Employee Andy C
Installed by:
Andy C
Employee Jameson C
Expert Research:
Jameson C
Employee Laura H
Updated by:
Laura H
Employee Wilson B
Updated by:
Wilson B
Employee Dustin K
Video Edited:
Dustin K

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