The push frame (12) of a tractor-scraper (10) normally has a plurality of cover plates (14) relasably secured therebelow to provide access internally of the push frame. In standard practice, the cover plates are secured to the push frame by a plurality of bolts and the heads of the bolts are subjected to wear and possible breaking-off due to their exposure upon operation of the tractor-scraper. This invention provides a mounting assembly (13) for expeditiously removing and replacing the cover plates upon wearing or breaking-off of the heads (19) of bolts (18) thereof by providing an internally and externally threaded bushing (24) which is threadably connected on the push frame and is further threadably connected to each bolt. Thus, a workman need only engage the bushing with a socket wrench or the like to release the bolt and thus the cover plate upon wearing or breaking-off of the heads of the bolts.