In HC95 Hydraulic Rock Drill (or Hydraulic Drifter) systems, the Hyd motor 86752615 is the “power core” for rotation—it converts high-pressure hydraulic energy from the system into mechanical torque, directly driving the drill’s shank and bit to rotate, which is essential for breaking rock. With over a decade in mining equipment maintenance, I’ve seen generic hydraulic motors fail drastically: most use low-precision internal components (e.g., gears, valves) that wear unevenly, leading to reduced torque output (dropping by 20-30% in weeks) or sudden stalling. These failures not only slow down drilling efficiency but also cause secondary damage to the transmission system—repair costs often exceed $8,000, and unplanned downtime can last 3-5 days, severely impacting mine productivity.