A carbon seal assembly comprises an annular seal runner adapted to be sealingly mounted to a shaft to rotate therewith. An annular member is secured to a structure, the annular member having an annular body and a projection extending from the body toward the seal runner in an axial direction relative to an axis of the runner. A axial gap is defined between the member and the seal runner when secured to the shaft and structure respectively, with the projecting extending into only a portion of the gap, such that the gap defines a first width portion and a second width portion, with the member and the seal runner being made of complementary materials for magnetic attraction therebetween. An annular carbon element is mounted to the seal runner to rotate therewith and positioned in the first width portion of the gap, the carbon element having an annular wear surface abutting against the annular member, a plane of the annular wear surface being axially offset from the second width portion of the gap.