A sweeping machine with a hopper and a dirt and debris control flap in the hopper. The sweeping machine includes a rotary broom adjacent the hopper opening which receives dirt and debris swept from a surface being cleaned by the broom. The hopper is maintained under negative pressure by a vacuum blower. A filter is also located in the hopper through which air is drawn by the blower. A dirt and debris control flap is pivotally mounted in the hopper with the flap having a first extreme position in which an outer edge of it is spaced adjacent an upper edge of the hopper opening and a second extreme position in which an outer edge is closer to a front end wall of the hopper. When the flap is swung from the first extreme position to the second the outer free edge of the flap moves through an intermediate position close to the bottom wall of the hopper and moves dirt and debris on the bottom wall toward the front end wall. The hopper also has a slanted baffle wall therein which directs air and air-borne dirt to the filter along with the flap, when in its first extreme position. When the hopper is dumped, the flap can be moved from the first extreme position to the second extreme position to enable loose dirt collected on the baffle wall and the flap from the filter to be dumped through the hopper opening.