track support surfaces 23 with the hangers 16 located on appropriate tracks 13 the door panels 11 can be bolted onto the hangers for example bolts not shown assembled vertically through holes in horizontal webs of the hangers 16 can be turned into threaded holes in the upper edges of the door panels 11 to secure the door panels to the hangers with each door panel 11 secured to a respective hanger 16 the panels are suspended overhead from the tracks 13 the bracket assemblies 26 afford a convenient accurate and fast way of adjusting a gap 61 fig5 between the bottom of the door panels 11 and the sill 21 to meet building code requirements and assure smooth opening and closing operation of the door panels with the nuts 54 slightly loose on the studs of the anchor bolts 51 the jack screws 41 can be rotated in either direction as needed to raise or lower the tracks 13 and therefore the door panels 11 the jack screws 41 bear against the top surface of their respective blocks 46 thereby transferring the weight of the tracks 13 and door panels 11 to the anchor bolt 51 while allowing the respective bracket assemblies 26 to move vertically within limits of.