New Brakes for '71 Safari

[TGK]

My Wife and I were on a recent trip in rural Northern California with our '71 23' Safari (tandem axle). When pulling out of the spot where we spent the night, the left rear wheel froze. I backed the trailer up and it broke loose. However, as I moved forward again, a disturbing noise could be heard. I drove the trailer about a quarter mile to the only gas station within 40 miles where l was fortunate to find a guy on duty who had been trained in the military to work on heavy vehicles and drive trains. He first thought it might be a seized bearing, but on close examination the bearing was in good shape. (I had them repacked 24 months ago and it showed no scarring or discoloration). It turns out that the brake on that wheel was disintegrating and a piece of it got loose and jammed the wheel. He removed the loose parts and cut the line to that brake. The other 3 brakes seemed to work fine and, since I tow it with a F250 Super Duty, I had plenty of weight in the truck to help with braking should the need have arose. Fortunately, on the way home to Portland, everything seemed to go smoothly and I encountered no further problems. I'm fortunate I discovered the problem when first putting it in gear that morning and not while climbing over the nearby 6,300 ft pass with steep grades on both sides.

So, given this experience and the fact that the trailer is 38 years old, I plan on replacing all the brakes on the trailer and have the bearings repacked while they are at it. I'm looking for input on what to get. I do not plan on doing the work my self and do not know much of anything about trailer brakes. There are no Airstream dealers in Portland (the nearest is 100 miles south). I called one of the local trailer supply & service outfit and, over the phone, they suggested replacing the backing plates. He asked whether the trailer had 10" or 12" drums, which I did not have the answer for. My manual says the trailer came with Kelsey Hayes Brakes. Lastly, I'm running the factory spec tire size of 7:00 x 15 6 ply tires on the original wheels. The wheels have a 6 bolt pattern and 6 x 5.5 bore size with zero offset. I've also been thinking about putting new wheels and tires on the trailer but have been told it is becoming difficult to find tires and wheels in that size.

Any input from those who are more experienced with brakes is appreciated. In addition, I'd also like to here about wheel / tire alternatives that would work for this trailer.

Thanks,

TK