A seal configured to extend circumferentially about a shaft , the seal comprising: a housing defining an interior cavity open towards a central axis of the seal ; a sealing element configured to move radially within the interior cavity in a manner to maintain sealing contact, the sealing element disposed within the interior cavity of the housing; a first seal disposed between the sealing element and the housing , the first seal maintaining sealing contact to limit fluid flow between the sealing element and the housing; a first element configured to move axially within the interior cavity in a manner to maintain sealing contact, the first element disposed within the interior cavity of the housing ; a second element disposed between the first element and the housing ; a second seal disposed between the first element and the sealing element , the second seal maintaining sealing contact to limit fluid flow between the sealing element and the first element during radial motion of the sealing element relative to the first element ; a biasing member disposed in contact with the first element , the biasing member configured to bias the first element towards sealing contact with the sealing element such that first element and the second seal maintain sealing contact during axial movement of an end face of the sealing element ; and a third seal disposed in a third seal cavity mutually defined by the first element and the second element , the third seal maintaining sealing contact to limit fluid flow between the housing and the first element ; wherein the third seal is disposed to limit fluid flow between a first portion of the cavity in fluid communication with a first fluid reservoir at a first pressure and a second portion of the cavity in fluid communication with a second fluid reservoir at a second pressure. a housing defining an interior cavity open towards a central axis of the seal ; a sealing element configured to move radially within the interior cavity in a manner to maintain sealing contact, the sealing element disposed within the interior cavity of the housing; a first seal disposed between the sealing element and the housing , the first seal maintaining sealing contact to limit fluid flow between the sealing element and the housing; a first element configured to move axially within the interior cavity in a manner to maintain sealing contact, the first element disposed within the interior cavity of the housing ; a second element disposed between the first element and the housing ; a second seal disposed between the first element and the sealing element , the second seal maintaining sealing contact to limit fluid flow between the sealing element and the first element during radial motion of the sealing element relative to the first element ; a biasing member disposed in contact with the first element , the biasing member configured to bias the first element towards sealing contact with the sealing element such that first element and the second seal maintain sealing contact during axial movement of an end face of the sealing element ; and a third seal disposed in a third seal cavity mutually defined by the first element and the second element , the third seal maintaining sealing contact to limit fluid flow between the housing and the first element ; wherein the third seal is disposed to limit fluid flow between a first portion of the cavity in fluid communication with a first fluid reservoir at a first pressure and a second portion of the cavity in fluid communication with a second fluid reservoir at a second pressure. <EOS>