This rubber cover shields the threshing unit from crop debris and dust ingress during operation. It mounts along the exterior of the threshing housing, protecting the rotating components from material buildup that can cause imbalance or premature wear. A torn or missing cover allows chaff and straw to pack around the drum bearings, leading to overheating and reduced bearing life. The cover is formed to match the contour of the housing and is secured with the original fasteners; on reinstallation, ensure the cover lies flat and is not pinched against any moving parts.