If your Von Duprin 9927 or 9827 bottom latch is dragging or scraping on the floor the most likely problem is the Top Latch.   On the Von Duprin 9927 or 9827, the  Top Latch Case does all the work.  When you press down on the cross bar, the rods retract the latches, and the top latch locks in the retracted position.   It remains in the retracted position until it closes and strikes the 299 standard strike.   Upon this contact it releases and gravity drops the bottom rod.  When the 9927 or 9827 Top Latch Case is worn, it will usually not lock in the retracted position, thus the bottom latch scratches or drags on the floor.   One way to test if this is the problem is to open the door by pressing the cross bar in and standing on a latter, and then trying to release the top latch with a screw driver.   If the bottom rod is staying retracted and the rods are not extending then the problem is somewhere else.  Other problems this causes are, the door will not close unless the the push bar is depressed, or the bottom rod and latch will not release and the bottom of the door will not lock.   The solution is easy, just replace the Von Duprin 9927 or 9827 Top Latch, part # 050091.  We offer the Von Duprin 9927 or 9827 Top Latch Case 050091 on our website along with the Von Duprin 299 Standard Strike.

The above image shows the replacement Von Duprin 9827/9927 Top Latch Case