A portable computer including two plastic enclosures has a first hinge body attached to a first one of the enclosures. The first hinge body includes a bore formed therein. A flowable lubricant such as grease is disposed within the bore. A second hinge body is attached to a second one of the enclosures. The second hinge body includes an elongated shaft pivotally mounted within the bore having grooves formed on an outer surface of the shaft. A sealing member such as an O-ring is resiliently compressed between one of the grooves and an inner surface of the bore. A friction member is seated in another one of the grooves and in contact with the inner surface of the bore. The seal member has a coefficient of friction such that friction between the seal member and the bore is negligible with respect to friction between the friction member and the bore. The seal member limits the escape of lubricant and the resulting lubricant-induced stress cracks.