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This Demco hydraulic actuator is made for trailers that need dependable stopping power. With an 8,000-lb gross towing weight and 800-lb maximum tongue weight, it’s built to handle tough jobs like farm or construction use. The steel body is heavy duty and comes primed, ready for paint once you’ve got it mounted. Whether you bolt it on or weld it to a 3" straight tongue, you’re getting a solid setup that’s ready for real work.
The built-in channel gives you options when lining up your coupler. It’s an 8" tall, channel-down design with three mounting positions so you can set your coupler (sold separately) exactly where you need it. That extra drop helps when you’re matching up a tall trailer for a level tow. The 3" wide channel works with standard ball couplers, lunette rings, or clevis attachments, making it handy for custom or replacement work.
Inside, the composite master cylinder uses glass-reinforced nylon that resists rust and corrosion. It’s efficient and durable enough for long-term use, with a large reservoir that keeps more brake fluid on hand to reduce refills. The automotive-style diaphragm cap seals the system to help keep out dirt and moisture, so the brakes stay reliable every time you slow down.
The actuator’s inner slide runs on an acetal copolymer lining that keeps motion smooth as it telescopes in and out under braking. A built-in breakaway system adds peace of mind by engaging the trailer brakes if it ever disconnects from the tow vehicle. It’s one of those details that make the whole setup safer without adding extra parts to install.
The primed finish means you can paint the actuator to match your trailer or leave it as is until the job’s done. Use 1/2" x 4-1/2" Grade-5 bolts (not included) if you’re bolting it on, or weld it directly for a permanent fit. Either way, this model gives you an easy bolt-on or weld-on installation that fits right into the way you like to build and maintain your trailers.
Because this actuator does not include a reverse lockout, it is recommended that you equip your trailer with free-backing brakes so that you can drive in reverse without the actuator triggering your trailer's brakes.
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 Eight Inch Adjustable Channel Down Hydraulic Drum Brake Actuator. Has an 8,000 pound gross towing weight capacity and in this prime finish. 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, deceleration occurs and the momentum will push your trailer toward the rear of your vehicle. So with the surge brake system, the actuator is then triggered as your trailer moves forward once your tow vehicle starts to slow down.
And when this happens, this inner slide portion will actually contract into the outer case and it applies force to the master cylinder that's in the back here. And this, in turn, supplies the necessary hydraulic pressure to engage your trailer's brakes. This one right up front here uses a nice acetal copolymer lining around here, which provides a nice, smooth operation as this inner slide will telescope in and out. This is an adjustable channel design, has three different mounting positions for your coupler. Now, the coupler is not included.
We do sell those separately on our website. We mentioned this is the channel down design, so you can see that the channel's actually positioned more downward. This allows for a greater drop to be used when you're using it on tall trailers. The channel height itself, if we measure it from the bottom to the very top is eight inches. The channel width is gonna be approximately, it's measured inside the inside, three inches.
This is a heavy duty steel construction, has a nice prime finish to it. Now, the master cylinder in the back here, they do use a composite master cylinder, which is durable and efficient. It's a glass reinforced nylon construction, resists rust and corrosion. Has a nice, large reservoir which provides increased capacity for your brake fluid. If you notice up at the top here where you put your brake fluid in, uses an automotive style diaphragm cap, which creates a completely enclosed system to help prevent contamination of your brake fluid.
Also, right up here at the very top, you can see this cable with the hook on the end. This is your brakeaway cable, and this is included, and it is required by law to be installed because basically, it's a safety feature, prevents a trailer runaway situation. Basically, when this is on the front of your trailer and you hook your trailer up to your tow vehicle, you'll take this hook right here, has a keeper on it, and you'll attach this to the tow vehicle also. And when you do that, it'll hold this cable taut just like that. And what happens is, in case this comes detached, your trailer comes detached from your tow vehicle. If it does, it would pull on this cable, which would pull the lever, and then that would actuate and in turn, supply the necessary pressure again in your master cylinder to engage the trailer brakes. So again, it's a safety feature. It prevents a trailer runaway situation. And as we mentioned, it is required by law. This is a bolt-on or a weld-on installation. It's designed mount to a straight three inch wide trailer tongue. This part is made in the US. Application, this will fit trailers with hydraulic drum brakes. Gross towing weight capacity is 8,000 pounds. Tongue weight capacity of 800 pounds. This does go by a model number of DA91. And one last note I do wanna mention about this, if you look at the back where the master cylinder is, because this actuator does not have a reverse lockout solenoid installed in here, it is recommended that you equip your trailer with either reverse lockout solenoid to the master solenoid right here, or to have free backing brakes on your trailer. And that's so that you can drive in reverse without this actuator triggering your trailer's brakes. But that should do it for the review on the Demco Eight Inch Adjustable Channel Down Hydraulic Drum Brake Actuator with the 8,000 pound gross towing weight 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