How to Bleed Brakes with Demco Hydraulic Brake Actuator

Published 01/30/2019

Question:

How do you go about bleeding the brakes on this actuator ?

asked by: Patrick M

Expert Reply:

I have attached an image from the operation manual for the Demco Hydraulic Brake Actuator # DM8669112 that details how to bleed the brakes.

The process consists of first elevating the trailer tongue about 4 to 6 inches and then loosening or removing the two 5/16" bolts that hold the lever guide and emergency lever spring and removing the master cylinder fill cap. You will want to use short strokes to pull the emergency lever forward, pumping the master cylinder until the brake fluid in the reservoir stops bubbling. Then attach a bleeder hose to a bleeder valve on one of the wheels (starting at the wheel furthest from the master cylinder) and submerge the other end into a clear container that's partially filled with brake fluid.

Loosen the bleeder valve one turn and while you're watching the fluid in the container, use the emergency lever to pump fluid for as long as bubbles continue to leave the submerged hose. When the bubbles stop you can close the bleeder valve and move onto the next wheel.

I have attached a video demonstration on this process that you might also find helpful.

expert reply by: Chris R