Recommended Replacement Brake Actuating Surge Coupler for Atwood 85778

Question:

I read a response about a Demko replacement for a different atwood drum actuator. My Atwood part #85778 has a reverse lockout. Do you have a replacement for my part either in Demko or titan? My trailers Atwood part is welded and the structure is 3 inch. I do feel it is in good working order but I suspect the master cylinder is leaking by and it is not actuating the wheel slaves. Is it possible to rebuild these masters?

asked by: Steve

Helpful Expert Reply:

Thanks for the photo. That is a great help for getting you the correct replacement. I recommend the Demco Hydraulic Trailer Brake Actuator - Drum Brakes - Zinc Plated - 2" Ball - 7,000 lbs # DM72VR for a zinc plated option.

This coupler does not have the reverse lockout, so you will need to add it using the Replacement Solenoid Valve for Titan Brake Actuators with Reverse Lockouts # T4748800 and the shield # T4835800183.

We don't have any Atwood replacement master cylinders any longer as they are no longer made. I've linked the page to all our master cylinder options available.

expert reply by: Jason S

click to enlarge

Michael P.

8/12/2020

I have a Zieman dual alxe with the ATwood 85837, and the master cylinder is no good. I realize that this isn't available anymore - and that I would need to replace the coupler. The current one is welded on - what would I need to replace it with. I need the brake lockout also.

Jon G.

8/26/2020

Does that actuator have a manual lockout or an electric lockout? That 85837 number you mentioned is the master cylinder and push rod assembly so if you can also let me know the weight rating for your current actuator that will help me choose a replacement for you out of the linked selection.

Helpful Links

dept-pg-brake_actuator.aspx

Michael P.

8/26/2020

@MichaelP Mine has the manual lockout and I believe is rated at 5000 lbs.

Jon G.

9/2/2020

@MichaelP Would something like the Brake Actuator # T4500600 work? It has a 7,500 lb weight rating, fits a 2" hitch ball, and has a manual lockout. This is a bolt-on installation and you can check out the attached answer page for the bolt hole locations.

Helpful Links

question-370523.html

Larry R.

4/8/2020

I have a 1997 EZ loader trailer with an ATWOOD surge brake actuator. In the course of replacing wheel bearings, I discovered it no longer is working and, then discovered the ATWOOD master cylinder is not longer available. There is no Model Number stamped on the trailer. The specs though, are for max 6000 lbs and it has a 2 inch ball. You recommended to another customer to replace this ATWOOD actuator with DEMCO 8605001. I looked at the specs and it appears it would replace, without modification, the ATWOOD actuator. However, I am somewhat puzzled as to the lack of a backup lockout. Do I need one? The trailer is equipped with free-backing brakes. So....I guess my questions are: Am I correct in assuming the DEMCO will bolt on without modification I realize I may have to reroute the brake line? Do I need to have a backup lockout?

Chris R.

4/11/2020

Since your trailer is equipped with free backing brakes - you really don't need a reverse lockout on the coupler. It would essentially represent a redundancy, as the free backing brakes already allow you to backup the trailer without having the brakes engage. Based on my research the Demco Actuator # 8605001 should indeed replace the existing Atwood unit without issue/modifications.