The floating seal is a kind of a combination sealcomposed of high hardness cast-iron seal rings and rubberO-rings. This seal, because its metal seal rings slide across
each other, has great durability against the wear by silt andsand. This, however, not completely resistant to the wear, isregarded to be an expendable part in which the wear due tosilt and sand proceeds as the operational time elapses. Longerlife of the floating seal, therefore, can improve availability ofa construction machine and decrease the life cycle cost.