Gives guidelines for the repair and remanufacture of safe, interchangeable wellhead and Christmas tree equipment. Includes recommendations for performance, design, materials, testing, inspection, welding, marking, handling, storing and shipping. Particularly intended as a guideline for repair and remanufacture of equipment not originally manufactured to, or lacking traceability to verify, API Product Specification Levels (PSLs) specified in the 15th and later editions of API Spec 6A. Use of this RP does not maintain the PSL Level for API Spec 6A 15th and later edition equipment. For information on maintaining the PSL level, refer to API Spec 6A, Specification for Valves and Wellhead Equipment.