A bearing and seal assembly for supporting a rotor for rotation about an axis in a rotor receiving bore of a rotating machine which is concentric to the axis of rotation. The bearing and seal assembly includes a nonrotatable bearing support member dimensioned to loosely fit inside the rotor bore so as to be radially movable relative to the axis of rotation. A bearing receiving portion is provided on the bearing support that holds a bearing which mounts the rotor on the bearing support member. A seal is nonrotatably mounted on the bearing support and has an outer peripheral portion dimensioned to have a close tolerance nonrotating fit with an inner peripheral surface of the rotor bore; an inner peripheral portion; and an nonrotating sealing surface dimensioned to have a close tolerance sealing relationship with a rotating sealing surface on the rotor. The bearing support has a radial dimension that is less than the radial dimension between a radial outer portion and an inner peripheral surface of the bore to permit radial adjustment of the rotor axis to locate a rotor sealing surface in concentricity with the nonrotating sealing surface of the seal. A releasable clamping device is provided for securing the members together to lock the rotor and seal surfaces in the position of concentricity.