Metcar® carbon- graphite bushings were designed for use in gear pumps that pump aviation fuel for aircraft engines. They are employed to support both the drive gear shaft and the idler gear shaft.  Metcar carbon-graphite bushings can use aviation fuel, a low-viscosity liquid that produces only an extremely thin hydrodynamic film, as the bushing lubricant. Carbon-graphite bushings are self-lubricating (meaning they can run dry for short periods of time without catastrophic pump failure or significant wear) and dimensionally stable, which permits the close bushing to shaft running clearances required in gear-pump applications. Metcar carbon-graphite bushings have a relatively low elastic modulus. As a result, they exhibit nearly the same coefficient of thermal expansion as the metallic gear-pump housing material. This ensures that the running clearance between the shafts and the bushings will remain the same throughout the entire operating temperature range of the pump.