The Rear Cover 86668670 protects critical rear components (motor, valve group) of HC25 Hydraulic Rock Drills and seals hydraulic ports to prevent leakage. Generic rear covers are often made from thin steel (≤6mm) that deforms within 1800-2200 hours, compromising sealing. This OEM cover uses thick alloy steel (≥8mm) for structural rigidity and features precision-machined 密封槽 (tolerance ±0.002mm) to fit  perfectly. Its impact-resistant design withstands mine debris, requiring replacement only if cracked or seal grooves wear out.