How to Bleed Electric Over Hydraulic Trailer Brakes

Updated 04/01/2019 | Published 03/29/2019

Question:

Best way to bleed the system

asked by: David P

Expert Reply:

Below is the general process for bleeding an electric over hydraulic brake actuator like # K71-650.

Fill reservoir with NEW brake fluid. Never re-use brake fluid that has been salvaged or removed from another system. Remove the key from the breakaway switch to start the unit.

Start with the brake furthest from the actuator. Open the bleeder screw and allow it to remain open until you see brake fluid that is free of air bubbles. Close that bleeder screw and move to the next brake and so on until all brakes have been bled.

While performing the bleeding process monitor the fluid level in the reservoir so that more air is not pumped into the brake lines because of low fluid level. To prevent spilling brake fluid on the ground one end of a length of plastic tubing should be placed over the end of the bleeder screw and the other end should be placed into a container so that the fluid flow can be monitored for bubbles. After all brakes have been bled replace the key in the breakaway switch.

expert reply by: Adam R