Apparatus is provided featuring a casing assembly, a shaft and an integral bellows type mechanical face seal. The casing assembly has an enclosing tube configured to house a stationary bearing and to contain lubricating oil. The shaft is configured to rotate in relation to the stationary bearing, the shaft having a rotating seal with a rotating sealing face. The integral bellows type mechanical face seal is configured with one end to overlap and couple to the stationary bearing of the enclosing tube, with another end having a stationary sealing face to couple to the rotating sealing face of the shaft, and with an intermediate bellows-like portion arranged under compression to urge the stationary sealing face against the rotating sealing face and to adapt to large variations between the stationary sealing face and the rotating sealing face in order to provide a seal for the lubricating oil contained inside the enclosing tube so as to prevent leakage of the lubricating oil and to isolate and keep clean the lubricating oil.