It is known theoretically and has been proved experimentally that, if both faces of a radial face seal, operating under a constant closure load, are misaligned, an axial vibration will occur. The frequency and amplitude of this vibration along with pressure distributions, friction torque, and leakage values are calculated here. Results show that a 4 to 1 increase in misalignment angle will cause the friction to drop by 20 percent, the leakage to increase by 100 percent, and the vibration amplitude to increase by 30 percent. This study will be extended to include other “surface defects” such as waviness. On the more fundamental side, flow considerations around the cavitation zone lead us to question the validity of the oil rheology model commonly used under actual working conditions.Presented at the 29th Annual Meeting in Cleveland, Ohio, April 28–May 2, 1974