How To Bleed Trailer Brakes

Updated 04/23/2010 | Published 04/21/2010

Question:

What is the best way to bleed the trailer brakes after installing the part # DM72VR

asked by: Norman

Expert Reply:

You are in luck! We happen to have a video on the proper procedure for bleeding trailer brakes. I have attached the video below as well as outline the method here for you.

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: Michael H