Replacement Drum Brake Actuator for a Atwood 85778

Updated 05/21/2026 | Published 05/14/2026

Products Featured in This Question

Demco Hydraulic Brake Actuator w/ Electric Lockout - Disc - Zinc - 2" Ball - 7,000 lbs

(145)

$226.16

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

(39)

$71.00

Question:

I have a 2000 boat trailer manufactured by Trailers by Dorsey, INC and the brake system on it is the Atwood system. I found the Part it tells me to refer to on top of the trailer - 85778 which brings me to a manual with the necessary information - I need to find a comparable replacement system for the trailer. Complete system everything for the brakes and I dont know exactly what to go with since I can no longer get the Atwood. What is recommended to replace with- with the least number of modifications needed to be made.

asked by: Ashley

Expert Reply:

Hey Ashley, thanks for the information! To replace a Atwood 85778 brake actuator, I recommend the Demco Hydraulic Brake Actuator item # DM62VR for drum brakes. It has the same 2" ball size and offers a bolt-on install for a 3" wide straight tongue.

Please note that the Demco Hydraulic Brake Actuator item # DM62VR has a manually lock out. If your boat trailer does not have free backing brakes, you can install the Reverse Lockout Solenoid Kit item # DM5836 which will automatically engage when you put the tow vehicle in reverse.

When you say complete system what exactly are you needing? If you need new lines, hubs, and brakes I'll need more some more information from you. Length of your trailer and how many axles for the lines. For brakes and hubs, I'll need to know the lug nut pattern of the wheels and the size of the spindle. There should be part numbers stamped inside on the inner and outer bearings that'll tell me what I need to know.

You can add this information, along with any other questions you have, where it says Add Comment.

expert reply by: Jerred H

DM72VR
(click to enlarge)

Big B.

5/15/2026

The actuator works very well. It did make me drill new mounting holes and that was the hardest part of the installation. All else was easy. I'm back to having a trailer I know will help me stop in a much shorter distance. Works very smooth no jerkiness. I'm very pleased.

Ashley

5/20/2026

I need to replace the wheel cylinders - the atwood kit # is 21669 - they are for the10" Uni-Servo Brakes - it includes the right and left wheel cylinder and the mounting screws. I need to replace the brake shoe and lining - Atwood Kit # 19862 - which includes the primary shoes with lining and the secondary shoes with lining. The last component that I need to replace are the Brake Shoe spring and hold down kit Atwood Part # - 23385 - It includes the primary and secondary retractor springs, the adjusting screw springs, shoe hold down pins, shoe hold down springs, shoe hold down washers. I am just looking for the direct replacements for these items. Or since the master cylinder would be changing what items comparable to these parts would work with it.

Jerred H.

5/21/2026

@Ashley Thanks for the information! I do have an option for you but we don't carry replacement brake components for Atwood Hydraulic Trailer Brakes as they have been discontinued by the manufacturer. Instead you'll want to replace your entire brake assemblies with the Hydraulic Brake Kit item # AKFBBRK-35-D. This is a set of left and right free backing brakes that are specifically coated for marine use.