According to a preferred embodiment, a mechanical face seal assembly comprises four generally ring-shaped members and plural spring devices. The first ring-shaped member is directly fastened (e.g., bolted) to the flanged structural section located at the end of the shaft sleeve. The first and second ring-shaped members are coaxially aligned and rotatively communicative at respective radial surfaces. The first ring-shaped member is made of a metal (or ceramic) matrix composite material. The second ring-shaped member is made of a polymer matrix composite material. The second and third ring-shaped members are mated via radial openings (in the second ring-shaped member) and corresponding radial projections (in the third ring-shaped member). The third ring-shaped member has axial projections and is thereby directly fastened (e.g., bolted) to the fourth ring-shaped member, which clampingly secures the third ring-shaped member with respect to the shaft. The third ring-shaped member contains the spring devices so that they push against the second ring-shaped member, which is consequently biased against the first ring-shaped member. Since each ring-shaped member is a “split” structure having two joinable semicircular halves, the entire sealing system can be installed without disassembling the shafting mechanism. The matrix composite compositions confer structural qualities on the first and second ring-shaped members, and further afford tribological “self-healing” properties of the wear junction therebetween. The resultant benefits include fewer parts, greater compactness, longer service life, and less frequent maintenance and repair.