Does the Demco DM72VR Replace an Atwood 171 Actuator and Can I Add a Reverse Lockout?

Updated 08/18/2026 | Published 08/12/2026

Products Featured in This Question

Demco Hydraulic Brake Actuator - Drum - Zinc - 2" Ball - 7,000 lbs

(428)

$182.10

Reverse Lockout Solenoid for Demco Hydraulic Brake Actuators - Non-Bypass

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$74.72

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

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$70.96

Question:

I am trying to replace an Atwood surge brake actuator. I know the master cylinder is the Atwood 171 but am not sure of the part number for the entire actuator. From your site I am gathering that I should purchase the DM72VR as a replacement. My question is, does this have a reverse lockout? If not, what parts do I need to be able to reverse without issue? I am not sure if my trailer has free backing brakes, but I would assume not. Thank you for your assistance.

asked by: Jeremiah C

Expert Reply:

Hi Jeremiah,

You're correct that the Demco Hydraulic Brake Actuator part # DM72VR is the replacement for your old Atwood 171 to work with your hydraulic drum brakes. The # DM72VR doesn't have a reverse lockout though, but you can easily add a reverse lockout solenoid to the Demco actuator using the Demco Reverse Lockout Solenoid Kit for Demco DA70 Hydraulic Brake Actuators part # DM5836. The # DM5836 is the complete kit with the solenoid as well as the solenoid cover. If you just need the solenoid and not the cover, you can use the Reverse Lockout Solenoid for Demco Hydraulic Brake Actuators Part # DM11993.

What kind of trailer are you replacing the actuator on?