The Demco hydraulic actuator brings solid control to heavy-duty towing. Rated for 8,000 lbs gross towing weight and 800 lbs maximum tongue weight, it uses a Bulldog Collar-Lok coupler that locks tight around a 2-5/16" hitch ball for a firm, no-slop connection. The pin-style fastener holds the collar securely, and the built-in 4" drop helps you line up your trailer level with your tow setup. Whether it’s a utility or construction trailer, this coupler gives consistent braking without the need for an electric controller.
The composite master cylinder is made from glass-reinforced nylon that stands up to rust and corrosion far better than steel or aluminum. Inside, an acetal copolymer lining keeps the moving parts running smoothly as the actuator telescopes in and out. The large reservoir holds extra brake fluid so you spend less time topping off and more time on the road. With its primer finish, the housing is ready for painting or coating to match your trailer frame once it’s welded in place.
This surge-type actuator automatically senses deceleration from your tow vehicle and applies pressure to your trailer’s hydraulic drum brakes. The process is fully mechanical—no wiring or brake controller needed. As momentum pushes the actuator forward, it compresses the master cylinder to generate hydraulic pressure, giving you steady braking power every time you slow down.
For extra peace of mind, a breakaway mechanism is built into the actuator. If your trailer ever separates from the hitch, the system automatically applies the brakes to bring it to a stop. It’s one more layer of safety built right into the same heavy-duty steel body you rely on for towing performance.
Designed for 50-degree A-frame trailers with hydraulic drum brakes, this unit welds directly onto a standard 3" channel tongue. Once your old coupler is removed, this one can be welded in the same position for a clean fit that’s ready to use. The DA91 model number makes it compatible with add-on accessories like the Demco reverse lockout solenoid if you decide to add backing functionality later.
Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.
Hello, neighbors, it's Brad here from etrailer and today I'm in Boyden, Iowa at the Demco headquarters and manufacturing facility where we got to see Demco products made. And these are all products that I handle on a daily basis when doing flat tows, fifth wheels, or even couplers. They cover so many different towing products and they have plenty of experts here to break down some of their products a little bit more to give you some understanding as well as allow me to ask those questions on products that I handle every day. So, Carter, what do we have here So, this is DA86 brake actuator model. This one is designed for disc brakes. We do also offer for drum brakes, as well, depending on what your trailer actually has on itself.
The nice thing about our actuators, they are all hydraulic-based, so they are all inertia-based. As you back up with the trailer, the brakes are applied as you back up and then going forward, obviously, when you come to a stop, the inertia on the inner slide tube itself will engage this as it's necessary. That will allow the brake fluid inside of the master cylinder reservoir here to go throughout the brakes. Brad So, what's the typical application for this So, this one here, this would be on smaller utility trailers, marine trailers, boat trailers. Obviously, with that as well, the plated finish here, a lot of marine applications will use that to prevent rusting.
That's kind of the main user for this. This is a light duty, so this is actually rated at 8,600 pounds. We do offer anything from 7,000 up to 20,000-pound actuators. So if I'm adding this to a trailer or replacing an old one, what's installation look like Yeah, so this one itself is a standard three-hole application. A lot of OEMs out there, trailer manufacturers out there, will have this standard three-bolt system on it.
We do have weld-on features, as well. A-frame options, definitely depends on what your trailer has as far as the application goes. We do kind of pride ourselves on flexibility with mounting applications, as well. So, it's designed to mount on a standard three-inch tongue, that's kind of industry standard out in the market. Basically, with this one, obviously, you'll have those three bolts that will allow you to take your existing one off, put this one on and away you go.
This red tab is catching my attention. I'm assuming that this is a lockout It is, you are correct, yes. So, most disc brake actuators will come standard with an electric lockout on the backside. Usually you have either a bypass solenoid or an inline solenoid that will just have two wires connecting to it. One's a power, one is a ground source. If there is a case where the ground is not proper, the solenoid isn't functioning like it's designed to, this is where this manual lockout comes into play. The nice thing with that, basically, all you would have to do in a standard situation, it would be down like that, flip the tab up. As soon as you back up, that does not allow for this inner slide tube to move in and apply those brakes. And then as soon as you pull forward with this, this tab would actually fall out of the way, that'll allow you to go in a normal state. Brad So, a nice little backup plan in case electronics aren't working, which I can imagine marine applications is probably one of those Right, yes, absolutely. So, obviously you wanna get your boat in the water. Best way to do that is to, obviously, backup with that. You don't wanna have the brakes apply when you do that. Obviously, it is a frustrating situation when the solenoid isn't working like it's designed to. So that's definitely a nice feature that that manual lockout comes into play. We got to see this manufactured today. Family-owned company here in Iowa, made in the US, so a great product. Carter, thank you for taking the time to show us your surge actuator. Yeah, thanks for stopping over. Appreciate it.
Ratings & Reviews
You did a great job and we received it very quickly. Thank you.
Great design. Easy to install. Very sturdy and excellent updated features
Perfect , the delivery was faster than expected. The product is real good quality.
Thanks for your great service.
Regards,
Marcel
perfect! its exactly what i needed.
Extremely happy with service and product. Thank You!
Good product for a reasonable price. Product availability and service was excellent.
Excellent product. Exact product as shown. Quality materials. Quick to ship and receive.
Super replacement and much cheaper than the bulldog style.
The people at E-trailer were very helpful and the product that came was exactly what i needed.
this hitch was by far beyound my expections they will get most of my business
Very happy with my purchase. It was a good price, easy to order and was received in short time. Thank you!
Very good product. I have been a fabricator for 42 years, and I will say this is very well made. etrailer.com is a great place!
Have not installed yet, but the product appears to be of high quality and heavy weight steel. Looks great.. would reccomend to anyone!
far superior to what it is replacing. well constructed, fast shipping.
Thanks again for supplies a quality product keep it up!
Really pleased on the outcome. I did have to paint where I had to weld. Would be nice to have the color to match the metal.
Amazing upgrade from magnetic brakes! Brittany was friendly, prompt, knowledgeable.
Very impressed! This will be perfect for my trailer rebuild.
Product has met my expectations. The customer service at etrailer is fantastic.
The product was just what I expected. The real story was that etrailer had a delay in shipping due to a manufacturer issue. Etrailer stayed in constant contact with me and made sure I was up to date on every stage of the order. AAA+ service...!!!
Thanks for your help in these trying times. I am restoring the surge brake operations to a 1985 Wells cargo enclosed trailer and performing all of the work myself. Not an easy task on a 36 year old trailer purchased new. I received this part and it is fantastic and arrived many days ahead of the projected delivery date. My prior orders also arrived early and the trailer brake parts and lines fit perfectly. Thank you for providing the service and knowledge to get me what I needed to restore an obsolete trailer. I can provide photos on completion. I may need to order new parts again in 36 years, I will be 94.
Yes i recieved the device , I'ts better than i expexted , very well built , Can definetely handle more weight than designed for, P/S I invented the device about 45 years ago. The device takes the shifting weight away from the hitch and tong of the trailer. The first device used a coil spring, The device i recieved uses a shock works the same as a coil spring.
excellent!. I painted with the trailer color
Awesome unit, but did not come with installation or system bleed instructions.
The weld on installation matched the trailer tongue angle perfectly and is a very rugged build. I connected the hydraulic line to the original brake tubing, bled the brake fluid through the system using pressure with the break away lever and put the trailer back to work. The braking power is smooth and consistent. The only trouble is when I back the trailer up an incline. I would purchase the backing option lever so you don’t have the trouble backing the trailer putting on the brakes.
Needed this for a water trailer. Couldn’t find one locally. Ordered and received very quickly. Item was as pictured and looks like it should work great!
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