This shaft seal prevents fluid leakage where the rotating shaft exits the hydraulic system housing. It sits in the seal bore between the shaft and the housing, maintaining a static seal on the outer diameter and a dynamic lip seal on the rotating shaft. A worn seal allows hydraulic fluid to weep past the shaft, which reduces system pressure and can lead to aeration of the reservoir fluid. The manufacturer machines the seal to the same interference fit and lip geometry as the original assembly, so the sealing lip contacts the shaft at the correct angle and pressure without requiring shimming. On installation, ensure the seal bore is clean and free of burrs, and lubricate the lip before pressing the seal into place.