How to Properly Bleed Brakes On a Tandem Axle Trailer

Updated 09/12/2023 | Published 09/11/2023

Question:

I just installed your brake line kit on my double axle boat trailer, It has your Kodiak 225 calipers for disc brakes.As they have 2 bleeding zerks my question is what is the correct procedure for bleeding,does it matter which one I start with? Thanks for your help

asked by: Burrel T

Expert Reply:

Yes it does matter and It sounds like you've never done this before, so I'd honestly recommend having a shop do it because this process is pretty specific and can affect your brakes if done wrong.

That being said, you'll begin by removing the master cylinder reservoir plug and filling the reservoir with brake fluid. You're going to need to use either DOT 3 or DOT 4 automotive brake fluid.

Do your best to avoid shaking the container, and pour liquid slowly to minimize air entrapment. Make sure you let the fluid in reservoir stand until it is completely free of air bubbles.

Before bleeding brake lines, bleed the actuator master cylinder. Insert a screw driver through the hole in the bottom of the inner member, and use short strokes to pry on push rod until no air bubbles are seen coming from small hole in the bottom of the master cylinder reservoir.

Start the bleeding procedure on the brake that is the furthest from the master cylinder. At the brake assembly, connect a transparent bleeder hose to bleed screw fitting on the wheel cylinder, and submerge the free end into a container that is partially filled with brake fluid.

This next bit will require help from another person. The first person will stroke the pushrod slowly, as they hold the safety release bracket up while the second person opens the bleed screw fitting. This person would then close the bleed screw fitting BEFORE the first person SLOWLY releases the pushrod. Repeat this until the fluid expelled from the bleeder hose is free of air bubbles.

Remember to always tighten the bleeder screw before releasing pushrod. During this process, the master cylinder reservoir fluid level must be maintained at no less than 1/2 full and you'll need to repeat this for the other brake, and the brakes on the front axle.

As a final check after the bleeding is completed, stroke the pushrod and check to be sure brake system is pressurized by attempting to rotate a tire. Push up on the safety release bracket to ensure that pushrod is in the released position. After bleeding has been completed, re-check fluid level in the master cylinder and fill the master cylinder reservoir to the indicator on reservoir plug.