Could be possible the rear hub seal leaking oil onto the brake shoes causing the smoke, look under the rv on the backside of the brake backing plate and you may see some oil residue...check out the other side it will probably be fairly clean with oil seal not leaking or brake not smoking...
17 Voltage 3970
1999 Freightliner Western Hauler CC/300 Cat/Chipped
2001 Ford F350 CC DRW/ 4x4/ 6 Speed/Chipped