[rellick]

Hi Bob, it sounds like you are facing the inevitable challenge of finding your brakes parts. I think you are on the right track with the f-600 ford parts. Sometimes you can rebuild wheel cylinders as long as they aren't pitted too bad, as far as seals and bearings you should be able to get part no's from them or match them up according to size at a bearing place.
If you have no luck with a parts place try a brake relining place, probably be best to take your parts right to them. Also tell them its for a f-600 TRUCK!! Not a motorhome, you will confuse them and chances are they will not help you. We both know there is no parts listing for a 72 Newell. Hope this helps and best of luck on your quest!!