The typical steering oil seal includes pinion oil seal, input shaft oil seal, rack oil seal and oil pump oil seal. because of different operatation pressure and movement mode, the profile design should be taken into consideration. Because the operatation pressure of rack can be up to over 15Mpa, A nylon support ring is usually assembled into the profile middle for rack oil seal to meet the requirement of lip bearing pressure. Meanwhile, in order to meet the low and high temperature for oil seal application, the material is usually HNBR. Estimation its quality can be done by the test of lip opening pressure and dragging force except the endurance, high and low temperature performance.