so i have a 62' schwinn cruiser with its stock 1pc cranks set and a single speed bendix "redline" coaster brake whell on the rear, also original. now i have rebuilt the hub like 5 years ago and the bottom bracket, since putting low miles on the bike. the other day, i noticed a rubbing or scraping sound, kinda faint but definatly making itself notice when i pedeled, but not when i coasted. i hear it from beneith me, maybe the bb or rearhub once per one revelution of the cranks and i first thought it was a rubbing chainguard, but it wasn't. i also rebuilt the bb again, inspecting the bearings and races b4 i repacked it and buttoned it all up, but the sound persists.
now, i have about ruled out the bb and wondering if this sound could be originating from the rear bendix hub? around the time i began to hear the noise, i then coasted and when i resumed to pedel, i had a split second of "neutral" before the driver in the hub engaged to power the bike. it was the only time it happened, it was brief and hasn't hapened since, even under heavy touque of "standing on the pedels" up hills.
what do i check next? i don't get easily stumped, but this one has got me. my next move was to find a doner rear wheel from another bike and test ride with it to see if the problem goes away, in which case it would have been the rear wheel at fault. the chain is cleaned, lubed with little milage and was a high quality bought at a LBS years ago. thanks in advance.