The performance of radial lip seals in either vehicular or industrial applications is a significant factor in the perceived quality of products. Lubricant leakage is high on the list of customer complaints or dissatisfaction. Radial lip seal suppliers have been working closely with vehicle manufacturers to improve the performance of their products. Much progress has been made. Advances from this point will depend not only on improvements in sealing technology but also on improvements in the control of the entire sealing system.