Troubleshooting Hydraulic Trailer Brakes Locking Up on One Side

Updated 04/18/2018 | Published 04/17/2018

Question:

I bought a boat with a 1998 tandem axle trailer unsure of the brand. The trailer operates with a hydraulic surge brake. The trailer was operated without the brakes engaged before I purchased. Twice I had the drums and backing plate completely replaced along with all the lines flushed obviously . What keeps happening is the the passenger side brake will stay engaged and will heat up the drum. This caused my tire to explode once. Luckily, I caught it the second time and disengaged the brake. Both times my brake pads were completely gone on that side after around a 100 mile trip. I feel nothing in my truck except maybe a little chug when I start to move forward after coming to a complete stop. The other side is completely fine pads and all.

asked by: Rudy M

Helpful Expert Reply:

If the brakes have been bled properly and your drums were replaced then the problem may be your wheel cylinder (see attached picture). Sometimes those can get worn out and then that pin will sit at an angle and prevent the piston from retracting.

You did say that your backing plate was replaced. I am not sure if you meant the whole brake assembly, like part # 23-312, or if you had just the backing plate replaced. Typically the whole brake assembly is replaced as opposed to just the baking plate.

If your whole brake assembly has been replaced, your hubs have been replaced, and your brake lines have been bled properly then you will need to take your trailer to a shop and have them physically inspect it. Replacing everything on your trailer should be taking care of that issue.

expert reply by: Jon G