The brake system is pretty basic on a trailer. I just bought this boat last August and I thought it might be a good time to flush the brake fluid, and it needed it. Who knows the last time it was done.
I started by sucking most of the old fluid out of the resevior, then refilling with fresh fluid. Installed the ball hitch in the receiver (not attached to vehicle) in order to activate the brake master cyl. Starting on the furthest bleeder screw (drivers side), I cracked the 3/8” bleed screw loose and attached the catch cup hose. The trick is to raise the cup above the bleeder screw. Once the fluid leaves the wheel cyl, any air in the line will continue to float up and away from the bleed screw. Any back flow will be pure fluid. Once the cup was in place, I used the attached hitch as a lever to pump the brakes. pushing slowly down and slowly raising the hitch, about 1/3 of the fluid gets purged. Refill the res each time. I cycled the brakes 5 times and checked to make sure the fluid leaving the bleeder looked new. Once the old fluid was removed, I locked down the bleeder, removed the hose and wiled it clean. Give the bleeder a final tightening and replace the rubber cap. Then move to the other side. Repeat
you do not need a pressure bleeder or a partner to pump the brakes like you do in a car. Just dont let the master run dry. I also use this method on my cars and it works great. Here are some pictures from the job. Note where the cup is and how the hose is routed.
I started by sucking most of the old fluid out of the resevior, then refilling with fresh fluid. Installed the ball hitch in the receiver (not attached to vehicle) in order to activate the brake master cyl. Starting on the furthest bleeder screw (drivers side), I cracked the 3/8” bleed screw loose and attached the catch cup hose. The trick is to raise the cup above the bleeder screw. Once the fluid leaves the wheel cyl, any air in the line will continue to float up and away from the bleed screw. Any back flow will be pure fluid. Once the cup was in place, I used the attached hitch as a lever to pump the brakes. pushing slowly down and slowly raising the hitch, about 1/3 of the fluid gets purged. Refill the res each time. I cycled the brakes 5 times and checked to make sure the fluid leaving the bleeder looked new. Once the old fluid was removed, I locked down the bleeder, removed the hose and wiled it clean. Give the bleeder a final tightening and replace the rubber cap. Then move to the other side. Repeat
you do not need a pressure bleeder or a partner to pump the brakes like you do in a car. Just dont let the master run dry. I also use this method on my cars and it works great. Here are some pictures from the job. Note where the cup is and how the hose is routed.
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