After 3 years (next month) my wife and I finally got our camper to the point where we can use it. Still lots of work to do but it is usable.
We took it on its maiden voyage this past weekend to a local campground to work out the bugs.
Prior to the trip we took the camper out for a test drive. The brakes were making noise so I took the brakes apart and cleaned everything, lubed the grease points, inspected everything and put it back together. Everything looked good.
The noise seems to have gotten worse during the first trip. It's like a grinding, clacking sound. Almost as if the drum is out of round and something is hitting a high spot as the drum goes around. The sound is continuous while braking and it changes with speed.
It seems to be a pretty simple braking system. I've taken apart plenty of drum brakes on passenger vehicles so this is not new to me. I'm confident that it is all put back together properly, I took lots of pictures before disassembly. I guess the PO could have put them in wrong. I did not replace any parts because they all seemed to still be in good condition.
I also notice that when I release the brakes the trailer brakes will make a loud click sound, one time only. I don't know if that is normal but I assumed it was just the return spring pulling everything back to resting position.
Before the next trip, I would take the wheels off and inspect the brakes. Sounds like something is hitting/rubbing as you apply the brakes. It could be something simple, but what you describe is not normal.
What happens when you spin the brake and apply power? (with the wheel off) I had a brake with weak wiring that did all sorts of weird things. You're right, the "click" could be just the brakes releasing. Another thought is your brake controller.Is it adjusted to minimum braking? Perhaps try that and then gradually increase?
Please let us know what you find. It will help all of us.