Hi Michelle
We had exactly the same thing on our Sterling Eccles Emerald.
Apparently it can be caused through a build up of brake dust in the drum although it would seem that it needs very little to cause it if the brake shoe / drum assembly are prone to creating the noise. We had our caravan serviced including cleaning out the dust from the drums before a holiday in France. The silence lasted for about 250 miles so we had a whole touring holiday of a couple of thousand miles with the noise that makes everyone look around.
We eventually remedied our problem by changing the brake drums. Our service engineer got our replacement drums from a scrap caravan that he had and charged us next to nothing for the work and parts. I think he was fed up with me complaining aboput the noise all the time !
Alko, who made our chassis and running gear, are aware that this problem can happen as they publish a leaflet that shows that the pads on the brake shoes can be grooved in very specific places. The idea is to reduce what I believe is sympathetic resonance. We were going to try it if the drum change didn't work.
Hope you get it sorted. We know how you feel !
Regards
John M
Facebook
Twitter