Just went thru this myself
I had the same problem. Turns out rust on the brake cylinder piston keeps the springs from being able to pull the brake pads away from the drum after the braking. I ended up replacing the entire brake foundation (that's everything except the drum) on each side of the trailer. You'll need to remove the tire, the outer bearings, the drum and then the inner bearings. Disconnect the hydraulic line from the back of the brake and then unbolt and remove the brake foundation. Reassemble and then bleed the brake lines. To bleed the lines I got a one man line bleeding kit at the auto store. It had a hose that attached to the bleed valve that ran to a catch bottle that had a magnet on it so you could stick it to the trailer frame. I pumped the coupler endlessly by hand with limited success. Got much better results chocking the trailer wheels very securely and repeatedly putting my SUV in reverse to activate the brakes. With the new brakes I also bought a flush kit. Once installed, it allows you to easily flush the salt water out of your brakes with a garden hose. Note that just changing the cylinder is also an option, but my brakes were so rusty and burnt (from locking up) that I decided to go the whole nine yards. Got my stuff from Eastern Marine in Delaware. They also have an "Online Trailer Parts Superstore." www.easternmarine.com/ Ron Mehringer h26 Hydro-Therapy
