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  1. Brake Actuator
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  4. Drum Brakes
  5. 1000 psi
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
Our Price: $857.06
Brake Actuator
Shipping Weight: 13 lbs
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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. 1-800-940-8924 to order Hydrastar brake actuator part number HS381-8065 or order online at Free expert support on all Hydrastar products. Great prices 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 (9)
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Hydrastar Brake Actuator - HS381-8065

  • 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.


  • 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

Customer Satisfaction Score:

Customer Reviews

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

Average Customer Rating:  4.8 out of 5 stars   (9 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.


It working good on my M105A2 Military trailer. Thanks etrailer.


Well built unit that works well .


Substituted the Hydrastar unit for the surge brake actuator on my military surplus trailer. Works like a champ!


Item arrived earlier than expected. Installation was easy. And now my trailer brakes work again.


Shipping box was ripped, should of had more packing material, fortunately everything was still in the box.


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 ...


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




See what our Experts say about this Hydrastar Brake Actuator

  • 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...
  • How To Choose Between a 1,000 Psi and 1,200 Psi Electric Over Hydraulic Actuator
    In regards to an electric over hydraulic actuator, the 1,000 psi model is for drum brakes and the 1,200 psi model is for disc brakes. The size of the axle, etc. are not factors. The most popular option we offer is the HydraStar Vented Marine Electric Over Hydraulic Actuator part # HS381-8067 for disc and part # HS381-8065 for drum.
    view full answer...
  • Replacement Brake Actuator For A 29ft Flatbed With Duel 10,000lb Axles
    I would probably go with the HydraStar Electric Over Hydraulic Actuator for Drum Brakes - 1,000 psi Item # HBA-10 for a trailer that has duel 10,000lb axles. It ensures you are getting enough pressure to your brakes on a trailer that size.
    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...
  • Which HydraStar EOH Actuator for Seasport Boat Trailer With 3500-lbs Drum Brakes
    In order to use the # AKFBBRK-35-D as electric over hydraulic brakes, I recommend using the HydraStar Marine Electric Over Hydraulic Actuator w/ Breakaway and 7-Way RV Harness - 1,000 psi # HS381-9065, which is the correct actuator for trailers with axle capacities of less than 7000-lbs each; this makes it perfect for your 4000-lbs trailer. I really like kit this since it comes with all of the parts you're going to need to make the switch from a pure hydraulic system to an electric over...
    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 time...
    view full answer...
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  • 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 junction box kit # HS381-9000 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 trailer. Let me know the size of your axle...
    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 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 weight...
    view full answer...
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  • 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...
    Image 1 for
  • Can Electric Over Hydraulic Brake Actuator Be Fully Submerged
    I spoke with my contact at Titan about the BrakeRite II # T4813102. 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 Over...
    view full answer...
  • Can Motor Be Replaced for Hydrastar Electric Over Hydraulic Actuator
    If the motor on your Hydrastar Electric Over Hydraulic Actuator went out then you'll need to replace the entire actuator as the motor is not a replaceable part according to my contact at Hydrastar. You'll just want to choose the actuator with matching specs to what you currently have: Standard: 1,000 psi - # HBA-10 1,200 psi - # HBA-12 1,600 psi - # HBA16 Vented: 1,000 psi - # HS381-8065 1,200 psi - # HS381-8066 1,600 psi - # HS381-8067 Attached are a few review videos for you to check out.
    view full answer...
  • 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. In regards to repose time, this goes to the Titan BrakeRite EHB with a response time of .3 seconds whereas the HydraStar Electric Over Hydraulic Actuator has a response time of .8 seconds. This is due to the five vs three piston pumps that each respective units use. In regards to the Titan BrakeRite EHB Electric-Hydraulic...
    view full answer...
  • Can Electric Brakes Be Used On Boat Trailer?
    There's plenty of new boat trailer manufacturer's using electric brakes on boat trailers, so you can absolutely do it, but there are a few key things. If you're removing the electrical connector before backing into the water like most do, you won't have trailer brakes which could make launching the boat interesting depending how heavy your boat is compared to the weight of your vehicle. Modern trailer wiring and brake assemblies are designed to be safe to be submerged for launching a...
    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...
  • 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...
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Info for this part was:

Employee Jeff D
Installed by:
Jeff D
Employee Adam R
Expert Research:
Adam R
Employee Leah S
Edited by:
Leah S
Employee Wilson B
Updated by:
Wilson B
Employee Manda E
Updated by:
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Employee Amanda M
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