Electric-over-hydraulic (EOH) trailer brakes use an in-cab electric brake controller to operate a hydraulic actuator. For hydraulic disc brakes, the Dexter K71-651-00 actuator is a direct option to compare; the replacement-style 12V models add stated wiring or battery-management features. The marine-grade actuator is another disc-brake option. The Demco DA70 is included as a useful contrast, but it is a surge actuator, not an electric-hydraulic unit.
| Product | Best suited for | Key detail |
|---|---|---|
| Dexter K71-651-00 | Disc-brake EOH systems | 1,600 PSI rating |
| K71-651-00 replacement, 12V | Specified replacement needs | Sleep mode and fluid guidance |
| Marine-grade EOH actuator | Marine trailer disc brakes | 1,600 PSI; disc-brake use |
| K71-651-00 actuator with wiring details | Buyers comparing installation details | 12V, four-wire design |
| Demco DA70 | Hydraulic drum surge brakes | Not an EOH actuator |
Dexter K71-651-00 Electric/Hydraulic Actuator
This Dexter actuator is designed to convert an electric brake-controller signal into hydraulic pressure for disc brakes. Its listed pressure rating is 1,600 PSI. That makes it a focused option for buyers whose trailer has hydraulic disc brakes and whose system calls for this type of EOH actuator.
- Best for: Trailer owners seeking an electric-hydraulic actuator specified for disc brakes.
- Why it stands out: The listing clearly identifies both disc-brake use and the 1,600 PSI rating.
- Limitation: The provided product details do not specify wiring, fluid, or axle-count requirements. Confirm those against the trailer and controller before buying.
K71-651-00 12V Replacement Actuator
This replacement-style actuator is listed as a direct drop-in replacement for the Dexter K71-651-00 and standard 1,600 PSI disc-brake actuators. Its stated fitment covers one-, two-, or three-axle heavy-duty boat, RV, and cargo trailers. It also describes reverse-lock-free hydraulic control and an automatic sleep mode intended to reduce idle power draw.
- Best for: Buyers replacing a specified K71-651-00 or comparable 1,600 PSI disc-brake actuator.
- Why it stands out: The listing provides fitment, 12V-system context, sleep-mode details, and DOT 3/DOT 4 fluid guidance.
- Limitation: DOT 5 use is described as requiring a complete fluid flush. Verify the existing system and fluid requirements before installation.
Marine-Grade 1,600 PSI EOH Actuator
This trailer-mounted electric-over-hydraulic actuator is described as marine-grade and intended for disc brakes. The listing identifies a 1,600 PSI rating, making it relevant to buyers comparing EOH units for a boat trailer with hydraulic disc brakes.
- Best for: Marine trailer owners who need an EOH actuator for disc brakes.
- Why it stands out: Its stated marine-grade construction and disc-brake application distinguish it from the general replacement listings.
- Limitation: The provided details do not explain wiring, fluid compatibility, fitment, or corrosion-protection specifics. Confirm these points with the seller and trailer specifications.
K71-651-00 Actuator With Four-Wire Design
This actuator listing specifies 1,600 PSI output for hydraulic disc brakes, a 12V power supply, and a four-wire design with color-coded leads. It also calls for a minimum 12.5V battery for reliable operation and describes a built-in sleep mode. These details help buyers assess electrical and installation requirements before choosing.
- Best for: Buyers who want stated voltage and wiring details when comparing a disc-brake EOH actuator.
- Why it stands out: The listing gives a minimum battery-voltage figure and specifies bolt mounting and level installation with the filler neck up.
- Limitation: The stated fluid compatibility includes DOT 3, DOT 4, and DOT 5; confirm that it matches the trailer’s complete brake system.
Demco DA70 Hydraulic Drum Surge Actuator
The Demco DA70 is not an electric-hydraulic actuator. It is a surge actuator designed for hydraulic drum brakes, with a listed maximum gross towing weight of 7,000 pounds and a 2-inch ball coupler. It is included to help shoppers distinguish a similar-sounding trailer brake component from an EOH system.
- Best for: Buyers specifically seeking a hydraulic drum surge-brake actuator with a 2-inch ball coupler.
- Why it is included: It is a trailer brake actuator, but its operating system differs from electric-over-hydraulic brakes.
- Limitation: Avoid this if you need an actuator controlled by an in-cab electric brake controller.
Buying Guide: How To Choose Electric Hydraulic Trailer Brakes
Do you need an EOH actuator or a surge actuator?
An EOH actuator receives an electrical signal from the tow vehicle’s brake controller and produces hydraulic pressure. A surge actuator responds to trailer movement through a mechanical coupling. These systems are not interchangeable. Check the trailer’s existing brake setup before choosing; the Demco DA70 above is for surge braking, not EOH operation.
Are your trailer brakes disc or drum?
Match the actuator to the brake type. Several products here specifically list hydraulic disc-brake use, while the Demco is for hydraulic drum surge brakes. Do not assume that a pressure rating alone confirms compatibility with every brake configuration.
What should you verify before installation?
Compare the actuator’s voltage, wiring, mounting instructions, fluid requirements, axle coverage, and fitment claims with your trailer and controller. The listings do not provide the same level of detail, so ask for clarification when a critical specification is missing. Follow the actuator’s installation instructions and consult a qualified trailer-brake technician if the system requirements are uncertain.
Why does battery voltage matter?
One listing specifies a minimum 12.5V battery for reliable operation, while another describes sleep mode to reduce power draw during storage. These are product-specific details, not universal requirements for every actuator. Check the chosen unit’s electrical instructions and maintain the trailer battery accordingly.
Frequently Asked Questions
What does an electric-hydraulic trailer actuator do?
It converts an electrical brake-controller signal into hydraulic pressure to operate the trailer’s hydraulic brakes.
Can an EOH actuator operate hydraulic disc brakes?
Yes, when the actuator is specified for disc brakes and matches the trailer system. The disc-brake products above list 1,600 PSI ratings or disc-brake use.
Is the Demco DA70 an electric-hydraulic actuator?
No. The listed DA70 is a hydraulic drum surge-brake actuator with a 2-inch ball coupler.
Can I use any brake fluid in an EOH actuator?
No. Use only fluid specified for the exact actuator and brake system. One listing gives DOT 3 and DOT 4 guidance and requires a complete flush before DOT 5 use.
Should I choose an actuator based only on PSI?
No. Also verify brake type, voltage, wiring, fitment, fluid, mounting requirements, and controller compatibility.