Is There A Manual Lockout Kit For The Demco DA66B Actuator?

Updated 05/22/2026 | Published 05/18/2026

Products Featured in This Question

Reverse Lockout Solenoid Kit for Demco DA66B and DA70 Hydraulic Brake Actuators - Non-Bypass

(37)

$67.60

Hydraulic Brake Kit - Uni-Servo - Free Backing - Dacromet - 10" - Left/Right Hand - 3,500 lbs

(388)

$144.70

Question:

Hi. Which manual backup lockout kit works with the Demco DA66B actuator? Not all vehicles have a brake solenoid. Need to know how to lockout when that happens. Thanks.

asked by: David L

Expert Reply:

Hey David, thanks for reaching out. Unfortunately, Demco doesn't make a manual lockout kit for the DA66B actuator. The Demco DA66B actuator doesn’t use the same style manual lockout as the newer Demco DA91 actuators, so the common # DM5939 manual lockout kit will not fit the DA66B.

On the DA66B, Demco intended you to use either an electric reverse lockout solenoid # DM5836 or to install free backing brakes like part # AKFBBRK-35-D (for 3,500 lb hydraulic brake axle) on the trailer. If your tow vehicle doesn’t have a reverse lockout circuit available, most guys add a 5-flat adapter # C57187 with reverse wiring. Those will be your best options for backing up without actuating the brakes.

Personally, I'd lean towards swapping out the brakes. It's not too hard to do and that way you don't have to deal with any wiring or adapters.

Do you know the weight capacity of your axle? Does it have electric or hydraulic brakes?

expert reply by: Jesse M

Hydraulic Brake Kit - Uni-Servo - Free Backing - Dacromet - 10" - Left/Right Hand - 3,500 lbs
(click to enlarge)

David

5/22/2026

Hi, Jesse. Thanks for your reply and suggestions. Brake axle is 3500lbs with disc brakes on a boat trailer. I don't want to go back to drums on a boat trailer. I searched the website and didn't find freebacking replacement calipers. Seems more trouble and expense than replacing the Demco actuator. I have to bleed brakes either way. I would think a manual lockout would be required by law. Electronic backup solenoids and wiring can fail. And then you're stuck. :-) This Demco replaced an Atwood. Demco's marketing is tacit on not having a manual lockout. etrailer may want to call it out on their website for the next guy. In the meantime, I'll rig something temporary with a 12v jumpstart battery kit. Thanks again for your help.

Jesse M.

5/22/2026

@David Ok gotcha yea there are no free-backing option for disc brakes only for drum. Electric lockout will be the way to go then. They are typically pretty reliable - we don't see many issues or returns on those. Sounds like your idea will work as long as the solenoid is getting 12v power it will do its thing. Let me know if there is anything else I can do to help!