Failure and repair data are urgently needed for reliability and maintainability analysis of production lines. A piston production line is traced, and field failure data during a period of 15 months are collected. The statistical analysis of the failure and repair data and the determination of the theoretical distributions parameters that best fit to failure data were carried out, based on which, reliability of the piston production line is evaluated from a global perspective. Furthermore, a failure losses-based importance measure method for repairable systems was proposed and used for reliability defects identification of the piston production line from a local perspective, the primary failure modes and equipments that were prone to failures were ranked with this method. This analysis will be essential and valuable to identify the reliability problems for current and further designing projects of production lines for piston or other important parts of motor engine.