When Replacing Trailer Brake Lines Is Bleeding the System Required to Get Fluid to Assemblies

Published 12/01/2015

Products Featured in This Question

Demco Hydraulic Brake Line Kit for Tandem Axle Trailers - Drum Brakes

(5)

$92.74

Powerbuilt Brake Bleeder - Master Kit

(15)

$7.36

Question:

Recently replaced mstr cylinder on old style DA91 actuator. Replaced all wheel cylinders, then tried to flush and bleed brakeline pneumatically. No brake fluid ever reached wheel cylinders. Old master cylinder was dry and rusty, so possibly brake lines have rusted up and plugged. With brake line disconnected at mstr cylinder, actuator was pumped and brake fluid would shoot out the orfice with new mstr cylinder. So, have decided to replace all brake lines and hoses and ordered a Kit. My question is, with or without the pneumatic bleed, does the actuator need to be engaged or pumped for brake fluid to reach the wheel cylinders? Thanks

asked by: Steve

Expert Reply:

You will need to bleed the brake system to get all of the air out of the lines after replacing the brake lines. Filling up the master cylinder will get some fluid into the lines but not a whole lot. You will need to keep bleeding them till there are no air bubbles that come of the wheel cylinders.

If you have a power bleeder you would not need to actuate the actuator to build pressure as the power bleeder will do that for you.

To make bleeding the brakes easier and quicker we have the # ALL648591 but it sounds like you already have a power bleeder.

expert reply by: Jameson C