Betting against a stand-pat in 7-card draw is equally risky. Buy new parts.
One rear brake applying before the other because of a weak spring will cause a drag and pull on that wheel under light braking. It is slight. I have identified which brake is the culprit by braking on a gravel hill and seeing which wheel leaves a skid mark in the gravel. If it's loose gravel it doesn't take much drag to show up in the tire track.