The functions of the Aston Seals SAD bi-directional rod wiper are:
- to prevent introduction of dust, dirt and foreign matter into the system; this is achieved by a special wiper lip which produces a very effective cleaning action, prevents the development of scores, protects the guiding parts and extends the service life of the axial moving rod seals.
- to retain residual oil film on the rod; the asymmetric lips are designed to differentiate the behaviour of the lips on the static and dynamic surfaces: the static lips are flexible and more sensitive to pressure fluctuations; the dynamic lip is shorter and stronger to concentrate load against the dynamic surface.
