I have what I believe is a 1970 Holiday Rambler Vacationer, and it has brakes on all four wheels. I have no idea how these work. They appear to have magnets on the wheels that rub against the drums. Is that correct? How does it work? The brakes shoes appear to be in good shape (look fairly new in fact although old). There is also an adjuster on there (they are pretty tight, hard time getting drums on/off to repack bearings). Right now the brakes do not work, do they need a battery? There is a battery mounted to the trailer but it does not work (broken post). There is also what appears to be an emergency stop cable that someone has cut off or is broken going to a small box on the tongue. Any help greatly appreciated! Thanks again.