The Bulldog-style Slide-Lok coupler fits tightly around the hitch ball and locks down with a sliding collar, keeping the jaws clamped in place for a solid hold. A safety pin secures the collar and jaws, so once it’s latched you won’t be second-guessing your hookup. With a 2" ball and 7,000-lb gross towing weight rating, it’s built to handle serious loads without worrying that the trailer might come loose.
Inside the actuator, the inner member glides on a heavy-duty plastic liner made from acetal copolymer. This material is self-lubricating, tough, and wear-resistant, so it moves easily every time the brakes engage. The smooth action means consistent braking pressure without sticking or jerking, even after years of use.
The glass-reinforced nylon master cylinder resists corrosion and pitting better than metal designs. Its large reservoir holds more brake fluid to help prevent low-fluid issues on long hauls, while the automotive-style diaphragm cap keeps contaminants out of the system for dependable performance.
This actuator comes primed for welding onto a 50-degree A-frame trailer tongue. The primed finish makes it easy to weld and paint, giving you a clean surface that’s ready to match your trailer. The heavy-duty steel body provides long-term strength once welded in place.
A breakaway cable is included to activate the brakes if the trailer separates from the tow vehicle. It connects with a snap hook for quick setup and adds one more layer of protection when towing heavy equipment or cargo.
Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.
Hi everybody. Andy here with etrailer.com. Let's take a brief look together at this Demco hydraulic drum brake actuator for A-frame trailers with a two-inch Bulldog coupler. Now this is also identified by the model number DA91, and this has a gross towing weight of 7,000 pounds and a maximum tongue weight of 700 pounds. And this is going to weld onto your 50 degree A-frame trailer with hydraulic drum brakes. And this hydraulic actuator will activate your trailer brakes when your tow vehicle slows or stops.
As you know, when you apply the brakes in your tow vehicle, deceleration occurs, and momentum pushes your trailer toward the rear of your vehicle. With surge brake systems, the hydraulic actuator is actually triggered as your trailer moves forward once your tow vehicle starts to slow down. When this happens, the actuator contracts, applying force to its master cylinder. This in turn is gonna supply the necessary hydraulic pressure to engage the brakes on your trailer. Now this does feature a Bulldog Collar-Lok coupler that's going to fit tightly around your two-inch hitch ball for a secure connection.
This has a pin-style fastener that's going to hold the collar in place around the base of the hinge ball socket. And lemme just give you a brief demonstration of how this is going to work. So I have a two-inch ball there, and so I'm going to, actually, I'm gonna move this around on the other side, so hopefully you can see that just a little bit better. I'm going to slide this collar back and that's going to pop our coupler open, as you can see there. And so I'm just going to put the ball in there and then slide this collar back.
Obviously this is gonna be easier to do when you have this mounted on your trailer. So slide the collar back, push that in, and then that collar will go right over there and then you're secure in place, just like that. And you'll replace your pin there and then that collar will be secure in there. And then to remove it, you'll just slide that collar back, and then that will allow you to disconnect from that ball. So slide this back into place, collar's back in place, and I'm just gonna slide that pin back in.
If you notice the pin is tethered by a chain, which is great, because that's going to help you not easily misplace that pin. Now the composite master cylinder is durable and efficient. Its glass-reinforced nylon construction's gonna resist rust and corrosion, and the large reservoir provides increased capacity for brake fluid. The automotive style diaphragm cap is going to create a completely enclosed system to help prevent the contamination of the fluid. And then it's probably gonna be a little bit difficult for you to see, but maybe you can see it right, I'm sorry, right through here. This has an acetyl copolymer lining, it's going to provide smooth operation, as this actuator telescopes in and out. It's gonna hold up really well for you. And then the breakaway is included with the snap hook, as you can see right here. And it's on this cable here that's going to activate your brakes in an event of a breakaway situation. So you'll just clip this on your tow vehicle, right around the same place where you're going to connect your safety chains. So this is a excellent feature to have, as most states do require having a breakaway lever and cable. Now this is made here in the USA of a heavy-duty seal construction with this primed finish. It's kind of like a beige color, if I was gonna put a name to that color. And I do wanna point out that 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 this actuator triggering your trailer's brakes. Well, I think that's going to wrap up our brief look today. I do hope that our time together was helpful for you. Again, my name is Andy. Thank you for joining me.
Customer Satisfaction Score:
89% were satisfied with this product
11% of customers were not satisfied
Ratings & Reviews
Great design. Easy to install. Very sturdy and excellent updated features
perfect! its exactly what i needed.
Perfect , the delivery was faster than expected. The product is real good quality.
Thanks for your great service.
Regards,
Marcel
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.
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!
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.
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.
Extremely happy with service and product. Thank You!
excellent!. I painted with the trailer color
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