HydraStar Vented Marine Electric Over Hydraulic Actuator for Drum Brakes - 1,000 psi

HydraStar Vented Marine Electric Over Hydraulic Actuator for Drum Brakes - 1,000 psi

Item # HS381-8065

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Brake Actuator

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Hydrastar Drum Brakes Brake Actuator - HS381-8065
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Product Images

  • Electric-Hydraulic Brake Actuator
  • Drum Brakes
  • Hydrastar
  • 1000 psi
Anodized aluminum electric-hydraulic actuator lets you use your brake controller (sold separately) to activate your trailer's hydraulic brakes. Includes rust-resistant marine-grade gasket and stainless steel hardware. Vented plate releases heat. Call 800-298-8924 to order Hydrastar brake actuator part number HS381-8065 or order online at etrailer.com. Free expert support on all Hydrastar products. Guaranteed Lowest Price and Fastest Shipping for HydraStar Vented Marine Electric Over Hydraulic Actuator for Drum Brakes - 1,000 psi. Brake Actuator reviews from real customers.

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  • Reviews (2)
  • Q & A (11)
  • Videos (1)
  • Photos
  • Why etrailer?

Hydrastar Brake Actuator - HS381-8065

Anodized aluminum electric-hydraulic actuator lets you use your brake controller (sold separately) to activate your trailer's hydraulic brakes. Includes rust-resistant marine-grade gasket and stainless steel hardware. Vented plate releases heat.


  • Electric-over-hydraulic brake actuator activates your trailer's hydraulic brakes when you apply the brakes in your tow vehicle
    • Brake controller (sold separately) is required to send signal from tow vehicle to actuator when brakes are applied
    • 7-Way trailer connector (sold separately) is needed to transmit signal from brake controller
  • Improved functionality when compared with surge brake couplers
    • Faster response time - trailer brakes are triggered when you apply brakes in tow vehicle, as opposed to when trailer pushes against hitch ball
    • No need to manually lock out brakes when you back up
    • Trailer brakes can be intentionally activated when you reverse
    • Manual override on brake controller can be activated so you can engage the trailer brakes without having to apply your vehicle brakes
  • Vented end plate releases pressure, moisture, and heat in order to protect the internal components
    • Allows actuator to be mounted in places where most actuators would overheat
  • Electronic, proportional pressure valve ensures that braking is smooth and effective
  • Built-in bleeder screw lets you easily flush air out of the brake lines
  • Durable extruded aluminum provides superior corrosion resistance
    • Marine-grade gasket and stainless steel hardware make this ideal for marine use
  • Compatible with any standard, 5-amp-hour-battery breakaway kit (sold separately)
  • DOT compliant
  • Unit installs on trailer frame and connects to trailer's wiring and hydraulic brake lines (sold separately)
  • Made in the USA


  • Application: single- or tandem-axle trailers (up to 7,000 lbs) with drum brakes
  • Maximum output pressure: 1,000 psi
  • Power: 12V DC
  • Hydraulic port size: 3/16"
  • Dimensions: 11-3/4" long x 3" wide x 7-3/8" tall
  • Wire configuration:
    • Black: 12-volt power
    • Blue: brake controller
    • Yellow: breakaway
    • White: ground
  • 2-Year limited warranty

Note: 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.

The HydraStar electric-over-hydraulic trailer brake actuator applies pressure to your trailer's hydraulic brake system in response to the electrical signals sent from your in-cab brake controller. As a result, your trailer's hydraulic brakes will be activated every time you apply the brakes in your vehicle or press the manual override on your controller. This setup is ideal for boat trailers because you will get responsive hydraulic braking, which you control conveniently from inside your vehicle with your electric brake controller.

HydraStar Electric-Over-Hydraulic Actuator vs. Standard Surge Brake Actuators

With the HydraStar electric-over-hydraulic actuator, you can get all the benefits of towing with an electric brake controller while using hydraulic brakes. Because this actuator will activate according to the settings you have chosen for your brake controller (sold separately), you will have more control over when and how your trailer brakes engage. Depending on the features of your brake controller, you may be able to control both the rate and intensity with which your trailer's brakes activate. You can also use the manual override on your brake controller, which allows you to engage the trailer brakes without having to apply the brakes in your vehicle. And perhaps most impressive, if you have a proportional brake controller, your brakes will be activated with an intensity that matches the braking speed and power of your rig.

This pump-and-motor-based system increases response time compared with traditional actuators because the trailer brakes are triggered when you apply the brakes in the tow vehicle, as opposed to when the trailer pushes against the hitch ball. This not only gives you faster, more efficient braking, but it also eliminates the pushing sensation that occurs in setups that use standard surge brake actuators.

HydraStar actuators are also beneficial because, unlike standard surge couplers, they allow you to activate your brakes when reversing down an incline, such as a boat ramp. Having the ability to brake in reverse gives you more control and prevents wear on your tow vehicle.

HydraStar Installation

Hydrastar Installation Diagram

This HydraStar electric-over-hydraulic brake actuator will give you years of trailer-stopping performance. The actuator mounts on your trailer's frame with the included stainless steel hardware. Then it splices into the trailer's wiring and connects to your hydraulic brake lines from the 3/16" female port. Lines and fittings are sold separately.

Durable, Marine-Grade Construction

The HydraStar Marine actuator is ideal for use on boat trailers. Just like other HydraStar electric-over-hydraulic actuator models, this system is built of extruded anodized aluminum for superior corrosion resistance. The weathertight seals protect internal components from the elements. The HydraStar Marine actuator also features marine-grade gaskets and stainless steel hardware that won't rust. These extra features make it perfect for marine applications.

This actuator also has a vented end plate that releases pressure, moisture, and heat to help prevent any internal damage. Unlike models that are unable to release heat and pressure, this vented actuator can be safely mounted inside of a compartment on your trailer. As a result, this actuator is great for gooseneck and fifth-wheel trailers where finding space on the tongue can be nearly impossible.

Brake Controller Compatibility

Not all electric trailer brake controllers will work with this electric-over-hydraulic brake actuator. See the following table to determine compatibility with common models of brake controllers. For best performance, it is recommended that you use an aftermarket electric brake controller rather than an OEM factory-installed controller.

ManufacturerVehicle Years/Controller ModelsCompatibleCompatible if Used with HBA-CAM
Brake ControllersDraw-TiteActivator (5100)Yes
Activator II (5500 or 5510)Yes
Activator III (5520)Yes
Activator IV (5504)Yes
HayesEnergize III (81741B)Yes
Energize III+ (HA81742B)Yes
Energize XPC (HA81745)Yes
Engage (HA81760)Yes
G2 Brake Boss (81792BB)Yes
Syncronizer (HA81725)Yes
Endeavor (81770)Yes
Genesis (HA81790)Yes
Blackbird (HA81726)Yes
HopkinsImpulse Digital (47325)Yes
Insight (HM47297)Yes
Brake Force (47225)No
Reliance (47284 or 47285)Yes
Agility (47294 or 47295)No
MaxbrakeBrake ControllerYes
RedlineRedline TA900Yes
TekonshaProdigy (90185)Yes
Prodigy P2 (90885)Yes
Prodigy P3 (90195)Yes
Primus IQ (TK90160)No
PowerTrac (39523)Yes
Voyager (39510 or 9030)Yes
ValleyVA32812 BlackbirdYes
VA32811 PhantomYes

381-8065 Cargo Towing Solutions (formerly Carlisle) Hydra Star Marine Grade Electric-Hydraulic (EOH) Actuator - 1000 psi - Model MHBA-10

Video of HydraStar Vented Marine Electric Over Hydraulic Actuator for Drum Brakes - 1,000 psi

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.

Video Transcript for Hydrastar Brake Actuator - Electric-Hydraulic Brake Actuator - HS381-8065 Review

Today we are going to take a look at the Hydrastar marine grade electric over hydraulic actuator for drum brakes, and this has a 1000 psi rating. Now this Hydrastar electric over hydraulic actuator will offer a fast response time for shorter stopping distances. In emergency situations, and even in your everyday towing, you can control those fractions of a second that matter when it comes to stopping your trailer. This actuator has the 1000 psi pressure which is suitable for drum brake applications. It will work on single, tandem, or triple axle trailers with drum brakes. This will eliminate the feel of being pushed by the trailer.

It also eliminates problems found when backing a trailer uphill with surge brakes, and will eliminate the brake drag which is common with surge brakes on a downhill grade. As you can see, this unit has a nice sealed extruded anodized aluminum housing. On the very end here, you can see right down below the wiring, there is a vent. This vented end plate allows the release of any moisture, pressure, and heat from inside the housing unit. This is a marine grade unit, and when they say that, the reason they say that is these black gaskets you can see right here when the unit is put together, they use a marine grade gasket, and then the hardware is stainless steel hardware, and this allows it to be less susceptible to corrosion and it will protect the internal components from the elements. This does mount to the trailer. It connects into the trailer's wiring right here, and the hydraulic brake line is right over here.

Basically if you notice on here, you have your filler cap right at the top. If we just turn that and pop it off, you can see this is where you put your brake fluid in, fill up the reservoir, and once you get it filled up, go ahead and put your cap back on and just twist it closed. Right here, you've got a bleeder valve on top. This bleeder valve is used to get air out of your hydraulic system. This is the output port.

This is where your hydraulic brake line will adhere to. This is your wiring. I'm going to go over these wires here in a minute, what connects to what. Now this does require the use of an in-cab brake controller. It works with most electronic brake controllers that have electric over hydraulic brake function on them. It also will require a breakaway kit.

If you do need one, we do sell those separately on our website. It is Part Number HS496-82. We do sell those separately, and we do list them on this product page as a related product. Now the wiring connects as a 12 volt DC operation. It uses solid state electronics. The brake fluid that you can fill this with is either DOT 3 or DOT 4 brake fluid. It will take either one. To put your cap back on, you just line that up, twist it, and it will lock it into place. Now the Hydrastar actuator is very easy to install. They meet all DOT and federal braking requirements, unlike some of your surge brakes which are illegal in many states. This does install as I mentioned using these four 12 gauge wires to connect to the wiring. We will start with the black wire. The black wire connects to your 12 volt constant power from the tow vehicle. Your blue wire connects to the output from your in-cab brake controller. The white wire is your ground wire. That will connect to the tow vehicle ground. Your last one, your yellow wire, that will connect to the cold side of your breakaway switch, not the battery side. It comes with a nice owner's manual here that will describe the operations of this part, and also how to install it. The last thing I want to do is give you some measurements so you've got an idea of the size of this. We will measure first the height from the bottom to the very top of the cap. If I put the ruler on this and just to give you an idea, you can see it's going to be about 7-1/4 inches tall up to the highest point. For the length, I am going to measure edge to edge, including these two mounting brackets here on the end. If we put the ruler edge to edge, it is about 11-3/4 inches long, and then the width of it is going to be right here. The widest part is going to be about 3 inches wide. That should do it for the review on the Hydrastar marine grade electric over hydraulic actuator for drum brakes with the 1000 psi rating.

Customer Reviews

HydraStar Vented Marine Electric Over Hydraulic Actuator for Drum Brakes - 1,000 psi - HS381-8065

Average Customer Rating:  5.0 out of 5 stars   (2 Customer Reviews)

Anodized aluminum electric-hydraulic actuator lets you use your brake controller (sold separately) to activate your trailer's hydraulic brakes. Includes rust-resistant marine-grade gasket and stainless steel hardware. Vented plate releases heat.

- HS381-8065

Easy install, works great. Installed a whole EOH system with this unit at the core. Excellent. 639734

- HS381-8065

a very nice woman took my order ...she said it would ship in x business days ....i said never mind that put down the phone and run and ship my order ..she laughed and said they didn't let her into the warehouse...however if she didn't pack it up herself immediately, someone else did ..i had it way before i expected it ...hydreastar product ..1sr one lasted about ten years of almost 5 days a week use on an equipment trailer ..i expect to get same service from this one ... 442152


Ask the Experts about this Hydrastar Brake Actuator
Do you have a question about this Brake Actuator?

  • Comparing the HydraStar Hydraulic Actuator and the Titan BrakeRite Hydraulic Actuator
  • It looks like you have certainly done your research in regards to the HydraStar Electric Over Hydraulic Actuator and the Titan BrakeRite EHB Electric-Hydraulic Actuator. Unfortunately, we do not exactly do extensive testing on either actuator therefore our knowledge comes from the manufacture and the reviews our customers submit on them. In regards to the Titan BrakeRite EHB Electric-Hydraulic Actuator you only have two options which is part # T4822500 (1,000 psi) if you have drum brakes...
    view full answer...

  • Parts Needed to Convert Boat Trailer to Electric Over Hydraulic Drum Brakes and Replacement Coupler
  • We do have everything you need to convert to 12" electric over hydraulic drum brakes for your boat trailer: - Hydraulic Brake Kit 12" - Free Backing # AKFBBRK-7-D - Mounting Bolts and Hardware for 12" Brake Assemblies # BRKH12 - HydraStar Vented Marine Electric Over Hydraulic Actuator for Drum Brakes # HS381-8065 - HydraStar Hydraulic Brake Line Kit - Tandem Axle # HS496-252 - Breakaway Kit with Built-In Battery Charger # 50-85-313 - Titan Zinc-Plated Straight-Tongue Coupler # T4853100 The...
    view full answer...

  • Can Actuator, Harness and Brake Lines be Purchased as a Kit?
  • The HydraStar Vented Marine Electric Over Hydraulic Actuator # HS381-8065 is available in a kit. The HydraStar Marine Electric Over Hydraulic Actuator with Breakaway and 7-Way RV Harness # HS381-9065 features the actuator, breakaway system and 7-way connector. The only other piece you'd need is the brake lines; for a single axle you would want the HydraStar Hydraulic Brake Line Kit # HS496-151 and for a double axle you would want # HS496-152. I've added links to video reviews of these...
    view full answer...

  • Recommended Electric Over Hydraulic Conversion for Dutchmen Voltage 3818 Toy Hauler Triple Axle
  • We do have the ability to convert your Dutchmen Voltage 3818 to Electric over Hydraulic brakes. First you will want the brake assemblies and for those, I recommend the Hydraulic Brake Kit - Uni-Servo - Free Backing - 12" - Left/Right Hand Assemblies - 5.5K to 7K # AKFBBRK-7 (one kit per axle). Then you will need brake lines like the Deluxe Hydraulic Line Kit - Tandem Axle - Drum # 9579-2 along with the Hydraulic Line Kit, 3rd Axle - Drum and Disc # 9579-01. Then I recommend the HydraStar...
    view full answer...

  • Can Electric Over Hydraulic Brake Actuator Be Fully Submerged
  • I spoke with my contact at Titan about the BrakeRite II # T4835700. He confirmed that they do not recommend completely submerging the BrakeRite. I also spoke with Dexter Axle to see if their Electric Over Hydraulic Brake Actuators, # K71-651, can be submerged. They confirmed that their actuators are not designed to be fully submerged. Though also not recommended to be submerged, the most likely contender to hold up to being fully submerged is the Hydrastar Marine Grade Electric...
    view full answer...

  • Troubleshooting HydraStar EOH Trailer Brake Actuator That Runs Without Brake Signal
  • If the fluid pump on your HydraStar EOH trailer brake actuator such as # HS381-8065 is activating just when it is plugged in to the vehicle (without you pressing the brake pedal or the manual override control on your brake controller) then chances are that you have a short in your wiring. What can happen is that another one of the circuits with 12V power is leaking over to the brake circuit. Sometimes this issue can be caused by corrosion of the vehicle socket and/or trailer plug. This...
    view full answer...

  • Does Hydrastar HS381-8065 EOH Actuator Have Enough Pressure for Tandem Boat Trailer
  • For your tandem axle drum-brake-equipped boat trailer you can use either a 1000- or 1200-lb rated electric-over-hydraulic actuator like the HydraStar # HS381-8065. In cases where the trailer is really long, then larger diameter brake lines may be required. But for your application with a tandem trailer for a 24-foot boat you will be fine with this EOH actuator.
    view full answer...

  • Brake Controller for Electric Over Hydraulic Brakes
  • I do have a great option for you, however your Tekonsha Prodigy RF Wireless Brake Controller # 90250 is not compatible with electric-over-hydraulic brakes. Unfortunately you will not be able to use the controller with your trailer after converting the braking system. For an excellent brake controller that is compatible with EOH brakes I recommend taking a look at the Tekonsha Prodigy P2 # 90885. This is a wired proportional controller that will activate the trailer brakes at the same...
    view full answer...

  • Recommendations To Use Brake Controller With Boat Trailer
  • Yes. Electric brakes can work fine on boat trailers. I recommend using components that are galvanized or otherwise more protected and unplugging your trailer from the electrical connection before backing into the water to unload or load. You can use the Epicord 7-Way Molded Trailer Plug with Junction Box - 10' Long # 277-000141 to make these connections, but again, disconnect before submersion to prevent electrical damage. You can use # 10-2-1 to wire your brakes on each side of your...
    view full answer...

  • Recommended Trailer Breakaway Kit and Hub/Drums and Hydraulic Brakes for Trailer with Dexter Axle
  • You can use Tekonsha Breakaway Kit # 50-85-313 along with your HydraStar EOH Drum Brake Actuator # HS381-8065. If you prefer, we also offer the HydraStar Marine drum brake actuator kits # HS381-9066 (1200-psi) and # HS381-9065 (1000-psi) that include breakaways and 7-way wiring parts. To find compatible hub/drums you will need to find the bearing part numbers from your current hub. Please refer to the linked diagram to see how these part numbers appear. You want to match up the axle...
    view full answer...

  • Will the Hopkins Reliance 47285 Work with the HydraStar Marine Electric Over Hydraulic Actuator
  • I spoke to my contact at HydraStar and they informed me that the HydraStar Vented Marine Electric Over Hydraulic Actuator for Drum Brakes part # HS381-8065 is indeed compatible with your Hopkins Reliance 47285. Please note that this actuator is for drum brakes. If you have disc brakes you will need an actuator rated for a higher output pressure like the HydraStar Electric Over Hydraulic Actuator for Disc Brakes part # HBA16.
    view full answer...

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Info for this part was:

Installed by:
Jeff D
Expert Research:
Adam R
Edited by:
Leah S
Photos by:
Zach O
Updated by:
Sarah W
Written by:
Amanda M

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