How to Bleed Trailer Surge Brakes

Updated 04/27/2015 | Published 04/25/2015

Question:

GA66 hydraulic brake actuator. A review says you have a video for bleeding the system. Where would I find that? I am trying to decide whether to replace my actuator or just dump my Demco trailer. Thanks for the info!

asked by: Mark M

Expert Reply:

I attached a video that details how to bleed surge brake actuators for you to check out.

First top off the master cylinder with appropriate fluid. Next you will want to pump the fluid from the master cylinder. You can do this by unbolting the plate that holds the lever in place and then use that lever to actuate the master cylinder and force the fluid through. On some units, you will have to manually activate it at the point where the hitch ball moves in and out. The model in the video has a lever underneath the unit you could use to actuate it.

Next, find the bleeder valve and open it. Take a rubber hose and slide it onto the bleeder itself and run the other end to a clear container. Using a clear container will allow you to see if any air bubbles rise up during the process. No bubbles means no air and that the system is full of just fluid.

Start on the wheel cylinder closest to the T where it splits off. When you get clear fluid running out through your bleeder valve and no bubbles, you can go ahead and pull it back and hold it there and then shut off the bleeder valve. Continue from the closest wheel cylinder to the T and work your way back to front if you have a dual or triple axle trailer.

expert reply by: Jameson C