A device for stabilizing pressure inside a gear's housing or a wheel's hub includes a bladder, and a conduit coupled to the bladder and coupleable to a volume containing a lubricant. The bladder includes a chamber having a volume, and is configured such that the chamber's volume increases as a fluid enters the chamber, and decreases as fluid leaves the chamber. The conduit includes a first end positionable adjacent the lubricant containing volume, a second end coupled with the bladder, and a passage between the first and second ends, and is configured to hold fluid disposed in the passage and direct the fluid between the first and second ends. When the conduit is coupled to the lubricant containing volume, the volume of the bladder's chamber, the passage of the conduit and the lubricant containing volume are isolated from the ambient environment.