This electric-over-hydraulic actuator gives you full control of your trailer’s hydraulic drum brakes right from your brake controller. Instead of waiting for the trailer to push against a surge coupler, the Hydrastar responds instantly when you hit the brakes. The electronic, proportional pressure valve delivers smooth, even braking at up to 1,000 psi, and the manual override on your brake controller lets you apply the trailer brakes independently when you need to slow things down on a hill or while backing up.
The large 32 oz reservoir is built to handle long brake lines and multi-axle trailers that need more fluid volume. The translucent tank makes it easy to check levels at a glance, so you always know your system is ready. A built-in bleeder screw helps you purge air from the lines quickly, keeping pedal feel firm and braking performance consistent every time.
The durable extruded aluminum body resists corrosion and stands up to wet or marine environments. Since it’s made for frame mounting, it stays protected yet accessible for wiring and maintenance. The 12V DC motor and high-quality seals are designed for dependable operation season after season—no rust, no sticking pistons, just reliable braking power.
This actuator ties right into your existing electric brake controller using standard color-coded wiring—black for 12-volt power, blue for the controller signal, yellow for breakaway, and white for ground. It’s compatible with any standard 5-amp-hour-battery breakaway kit (sold separately), so if your trailer ever separates from the tow vehicle, the brakes engage automatically.
Installation is straightforward—mount it on the trailer frame, connect the 3/16" hydraulic port, and wire it up. The translucent reservoir and external bleeder screw make upkeep simple. DOT 3 or 4 fluid keeps things running smoothly, and since everything is sealed against dirt and moisture, you can count on consistent performance every trip.
Do not power wash the Hydrastar actuator or take it through a commercial car wash. High-pressure water may damage the seals on the actuator.
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 the Hydrastar Electric Over Hydraulic Actuator for drum brakes. Has a 32 ounce capacity and a 1,000 psi output pressure. Now, with a huge reservoir that holds a full quart of fluid, this actuator's perfect for your big multi-axle camper. Application, will fit single tandem and triple axle trailers with drum brakes. It is an electric over hydraulic brake actuator, so it does activate your trailer's hydraulic drum brakes when you apply the brakes in your tow vehicle.
A brake controller is required to send that signal from the tow vehicle to the actuator when your brakes are applied. The brake controllers we do sell separately. Also, you'll need a 7-way trailer connector, and that's needed to transmit the signal from the brake controller. This will give you improved functionality when compared with surge brake couplers, 'cause it'll give you a faster response time. Your trailer brakes are triggered when you apply the brakes in the tow vehicle as opposed to when the trailer pushes against the hitch ball.
There's no need to manually lock out your brakes when you back up, and the trailer brakes can be intentionally activated when you reverse. The manual override on the brake controller can be activated, so that you can engage the trailer brakes without having to apply your vehicle brakes. As we mentioned, this has a huge reservoir. It's great for trailers with long brake lines that need high volumes and brake fluid. As we mentioned, this has a fluid capacity of 32 ounces.
Right up at the top here, you'll notice it is a translucent tank, and that lets you check the fluid level at a glance. Now, it does require DOT 3 or DOT 4 brake fluid. It is not included, you would have to supply that. They do use an electronic proportional pressure valve to ensure that the braking is smooth and effective. Right up at the top here, has a built-in bleeder screw, which will let you easily flush out air of the brake lines.
And right down here is where your brake line attaches. As you can see, this is a nice, durable, extruded aluminum construction, provides corrosion resistance. And it is compatible with any standard five amp hour battery breakaway. This unit will install on your trailer frame, connects to your trailer's wiring and the hydraulic brake line. The brake lines we do sell separately. This part is made in the USA. Power for this is 12 volt DC power. The maximum output pressure is 1,000 psi. It is DOT, Department of Transportation compliant. We mentioned it connects to your trailer wiring. And if we pull out our wires here just to show you, there's four wires. And basically, the black one is for your 12 volt power, the blue one is for your brake controller, yellow is for your breakaway, and the white is for the ground. And the last thing, just give you the mentions on this. If we measure the length, if you noticed at the bottom, it has this mounting tabs. So we're gonna measure from the edge of the mounting tab to the edge of the mounting tab. So if we do that, that's gonna be right at 11 3/4 inches long. The width, the widest point, right at three inches wide. And the height from the bottom to the top of the cap here is gonna be right at 10 3/4 inches tall. But that should do it for a look at this Hydrastar Electric Over Hydraulic Actuator for drum brakes.
Ratings & Reviews
Adapters to fit brake lines are hard to find … they should include the fittings
Awesome product, the shipping was incredibly fast for shipping to Canada. Amy was a huge help as I was having issues with payment, and she figured it out instantly. Definitely will buy from them again.
awesome product, I have installed 4 more for customers,, works great, very easy to install and do away with surge brakes,, its a 5 out of 5 ,,, ill be buying more
It's been a good kit so far!! Had all the supplies I needed when installing it on my 30' float. Worked good on my Alko/kelsey hayes brake kit.
I just got it put on the trailer so really haven't had a chance to try it .
The part went on the 3 horse living quarters trailer which I hope to pull later today. The brakes activated properly, bleeding process was certainly a two man operation and took quite a bit of time.
Work Great Fast Shipping
The delivery was fast and the product was a perfect fit
The controller is still working. It tends to run at a low rate even when we're not braking, but perhaps it's something with our pickup or trailer wiring.
Loved going from Surge brakes to Electric, made a HUGE difference! Make sure to follow the directions, the color coding is not US standard when it comes to green, yellow, brown. BUt works great and easy to bleed.
This company is excellent! They have things I didn’t
even know I needed. Quick turn around time. Couldn’t be easier to get lights, hitches, jacks, brake controls (electric or electric over hydraulic). Been using this company for years and never had a problem.
I have a tandem axle dump trailer that came with factory hydraulic surge brakes. They worked sporatically at best, were very unpredictable, and eventually stopped working all together.
I installed the hba 10 as well as an electric breakaway switch and eliminated the surge hitch all together.
Works great. Far beyond my expectations.
Great product. Low maintenance. Small enough to put in almost any location. I put mine in a side tool box just above my trailer axles. Breaks engage as soon as pedal is engaged.
Still working as it should, no problems with the actuator. Completely satisfied! If only the rest of my braking system were as trouble free!
Very good product, it works well with my trailer. Much better than electric drum brakes. Only down fall is I found it is sensitive to voltage spikes. I had a faulty alternator and the control board in the unit burnt out. Somewhat disappointed that replacement parts were not available to repair my current unit. Had to replace that whole unit just for a small circuit board. Great unit otherwise as far as function.
I need to know how I can connect this 4 color wires on hydrastar actuator to my kaufman trailer??
I recently upgraded my trailer from an electric brake system to an electric over hydraulic brake system. I had heard good things about the actuator that etrailer sells, so I decided to give it a try. I'm glad I did. The actuator made the upgrade very easy. It was very easy to install, and it works fantastically. I would definitely recommend it to anyone considering an upgrade to their trailer brakes.
Been a year, haven't had one issues, very easy install. I went with the hydrastar unit so that i could utilize the brakes from a rear dana 60 axle, from a old service truck that i made into a trailer. The brakes function great. I recommend this unit to any one that is looking for a good solution to trailer braking using hydraulics, this system will also replace a surge brake system and operate much better. etrailer also had great follow up and customer care to see if I was satisfied with the unit which I am!
I am super happy with my replacement of the electric brakes on my camping trailer with this Electric Over Hydraulic Actuator and Hydraulic Brakes. It works SO much better than electric brakes ever did. I feel much safer towing the trailer now.
Came packaged safely and securely, everything was there as advertised. Parts look just as listed. No issue with install on etrailer's end. Will definitely be a repeat customer as needed.
Hooked it up and wired it in , everything worked flawless.
I am more impressed with the service I received from both representatives, Thomas and Justin. You both went above what is considered customer service in this day and age and I appreciate it! As for the part...exact replacement and is working as expected.
I WOULD BE OUT MANY THOUSANDS OF DOLLARS IF IT WASN'T FOR THIS AMAZING DEVICE! I'M A FARMER, AND DEPEND ON MANY THINGS TO GET THE JOB DONE RIGHT. THE HYDRASTAR ELECTRIC OVER HYDRAULIC ACTUATOR HAS MADE IT POSSIBLE FOR ME TO DELIEVER MY FRUIT TO THE WAREHOUSE, INSTEAD OF RELIEING ON THEM PICKING UP MY FRUIT. I'M SAVING THOUSANDS!!! THIS IS AN AMAZING SYSTEM THAT CAN HANDLE OVER 32,000 POUND LOADS. I WOULD BUY IT AGAIN, AGAIN, AND AGAIN! THANK YOU!
the unit itself is easy to install and is working great,I bought it last March/April and unpackaged it and installed on during off season in Dec. and noticed the fill cap broken during shipping to Canada, etrailer said they would not replace the $XX.00 cap because too much time has passsed,so un package ASAP.
Otherwise there prices are great.
Info for this part was:
At etrailer we provide the best information available about the products we sell. We take the quality of our information seriously so that you can get the right part the first time. Let us know if anything is missing or if you have any questions.
Thank you! Your comment has been submitted successfully. You should be able to view your question/comment here within a few days.
Error submitting comment. Please try again momentarily.