By: Frank Lanier
I have a 2006 Karavan trailer with surge drum brakes on both axles. I replaced the actuator, the brake lines (from metal to flexible lines), the distribution points for the brake lines, the backing plates and the drums. Since the time I replaced everything, I am having problems with the brakes not releasing, causing the drums to heat up (quite a bit). The trailer has not been dunked into the water since I replaced the brakes, and I am using Tie Down-recommended brake fluid. I bled the brakes. I also cranked the adjusting nut for the brakes to the point where they would no longer contract. If I manually apply pressure to the actuator and try to rotate the tire, the brakes engage and make it impossible to spin the tire. When I release the pressure on the actuator, you can hear the springs in the drum compressing, and the tires will rotate. When I hook the trailer to the tow vehicle and drive down the road (not even half of a mile), the brakes are too hot to touch. When I apply pressure to the actuator, I have a good flow of brake fluid at the bleeder valve and the brakes engage. It appears that while towing the trailer the drums heat up, and the brakes noticeably drag. The only other thing I can think of is there is debris in the brake line or distribution blocks. But I have sufficient pressure to engage the brakes, so pressure is good going out, it is just trying to get the brake cylinders to retract. What am I overlooking?
It sounds like you have a partial blockage or something that isn’t letting the pressure for the brakes release. I had a similar problem with one of the brakes on my old 1953 Willis jeep. It turned out to be a deteriorated brake hose. Pushing the brake pedal provided enough force to move brake fluid through the hose, but the inner liner collapsed when I let off of the brake, keeping the pressure on and the brakes engaged.