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This actuator is made for serious towing jobs. With a 20,000-lb gross towing weight and 2,000-lb maximum tongue weight, it’s built to handle large trailers that use hydraulic drum brakes. The heavy-duty steel construction gives it the strength to stand up to demanding use, while the weld-on design keeps it securely mounted to a 3" wide straight trailer tongue. It’s primed and ready for paint so you can match it to your trailer once installed.
The adjustable channel gives you five different mounting positions for your coupler (sold separately). It’s a smart setup when you need to fine-tune the height of your hitch for a level towing position. The channel-down layout provides extra drop, which helps line up taller trailers more easily. Whether you use a standard ball coupler, lunette ring, or clevis attachment, this design makes it simple to dial in the fit you want.
The composite master cylinder uses glass-reinforced nylon that resists rust and corrosion better than steel or aluminum. Inside, a large reservoir increases brake fluid capacity, which helps maintain pressure and smooth braking over long hauls. The automotive-style diaphragm cap seals the system completely to keep out moisture and contaminants. Every press of the tow vehicle’s brakes triggers steady hydraulic pressure for dependable stopping power.
The actuator’s inner slide moves on an acetal copolymer liner that keeps the telescoping motion smooth every time the trailer pushes forward under braking. A built-in breakaway lever adds an extra layer of safety by applying your trailer’s brakes automatically if it ever disconnects from the tow vehicle. The snap hook on the safety cable ensures a secure connection so it’s ready when you need it.
Designed for weld-on applications, this unit mounts solidly to your trailer frame without bolt holes to weaken the tongue. The primed finish protects against corrosion during build-out and gives you a clean surface to paint once installed. With steel housing that measures 19-3/4" long by 4-1/2" wide by 6" tall, it fits neatly on most standard builds while offering long-term durability in tough environments.
Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.
Hello everybody, this is Jeff at etrailer.com. Today, we're gonna take a look at this Demco 12 inch Adjustable Channel Down Hydraulic Drum Brake Actuator with a 20,000 pound gross towing weight capacity. Now, this hydraulic actuator will activate your trailer's brakes when your tow vehicle slows or stops. Basically, what happens is when you apply the brakes in your tow vehicle, the deceleration occurs, and the momentum will push your trailer toward the rear of your vehicle, and with this surge brake system, this actuator is triggered as your trailer moves forward once your tow vehicle starts to slow down. And when this happens, the actuator will contract, it applies force to the master cylinder in the back here, and this in turn supplies the necessary hydraulic pressure to engage your trailer's brakes. Now, this does use an acetal copolymer lining between the inner and the outer case, provides a nice smooth operation as this actuator telescopes in and out.
You can see it is an adjustable channel up front here, has five different mounting positions for your coupler. Now, the coupler's not included, we do sell those separately on our website. Now, the height on this channel, we go from the very bottom to the very top, it's right at 12 inches tall. The width, which will be measured inside to inside, it's right at three inches. If you noticed, this has a nice primed finish to it to help prevent rust and corrosion, and this is a heavy-duty steel construction.
We mentioned the master cylinder back here, it is a composite master cylinder, which is very durable and efficient. Uses a glass reinforced nylon construction to resist rust and corrosion, and it offers a large reservoir, provides increased capacity for your brake fluid. You can see up at the top here, uses this automotive style diaphragm cap to create a completely enclosed system, helps prevent contamination of your brake fluid. And this does include this breakaway cable and hook. Now, that is required by law, and the reason is it prevents a trailer runaway situation.
Basically, when you install this or hook up to your tow vehicle, you'll take this cable with the hook and the keeper here, and you'll run this to the tow vehicle, hook it under the tow vehicle, so what happens in case of this becoming detached from your tow vehicle, it'll pull on this cable, which will activate the lever here, again, which will activate the brake cylinder back here to apply the brakes in a runaway situation. And again, it is required by law and it is included. Now, this is a weld-on installation. It does mount to a straight three inch wide trailer tongue. It is made in the USA.
Few specs again, this is for trailers with hydraulic drum brakes, gross towing weight capacity on this is 20,000 pounds, maximum tongue weight, 2,000 pounds, this goes by a model number of DA20. And one last note I do wanna mention on this, because this actuator does not include a reverse lockout, it is recommended that you equip your trailer with either a reverse lockout solenoid that'll install right back here, or free backing brakes on your trailer, so that you can drive in reverse without this actuator triggering your trailer's brakes. But that should do it for the review on this Demco 12 inch Adjustable Channel Down Hydraulic Drum Break Actuator with the 20,000 pound gross towing rate capacity..
Ratings & Reviews
Victoria H.
11/19/2024
Hi Holger, this should've been packaged better. Let me make this right for you.
Do you have a question about this Brake Actuator?
Info for this part was:
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Jeff M.
9/3/2025
No problems works as it should