Our understanding is fairly simple, and you might be better served calling BCB internally. Our take is to removed the master cylinder and replace the unit if you are doing a complete. The Master Cylinder mounts by either the pin style on the newer models since 2000, or the old style Attwood bolts from the top. The wheel cylinders are easy to install, and make sure you get the front and rear brake shoes in their proper places, or the trailer will not back up on drum brake models. Bleeding can be done through either pressure on the reservoir tank if you have access to the apparatus, or vacuum bleeding. The most common method is to pump either the safety cable or the master cylinder actuator. You can use a receiver hitch on the older model, or pump the actuator by leverage on the newer model, sort of using a pry bar on that. The bleeding is done by holding pressure on the master cylinder, and releasing the wheel cylinders at the bleeder one at a time. You must tighten the bleeder before releasing pressure, or the air will reenter the system. So: 1. pump 2. loosen bleed screw moving fluid out 3. tighten bleed screw 4. release master cylinder 5. repeat process till fluid is air free 6. check reservoir on the master cylinder frequently, filling at half reservoir. The bleeders must be done independently, starting at the closest to the system, and with a clear tube attached, which runs into a clear bottle. Continue to bleed the lines till the tube in the bottle produces no air in the tube, and you are then free to move to the next further bleed screw. Repeat the process after you completely bleed the system a second time for security and to remove those last air bubbles. Be sure to remember to fill the reservoir in between pumping to make sure you have fluid in the reservoir. If you dry the reservoir, then you must start over with the bleeding procedure. Once you have bled the system twice you should be done with bleeding. BCB
