b'MULTI-WAY BALL VALVES - BV509/509A, BV2057, BVL50~L54, SL8142-FZ SERIESNut type packing retainerFIG 5. CONSTRUCTION FOR GLAND PARTS FIG 5A. STEM PACKING4.2 BODY SEALSealing between two body segments is provided with a gasket (Teflon or graphite) In case of slight leakage the fastening bolts (or threaded body connection) can be lightly tightened up (flange body version). Refer bolting torques in Appendix A table 2.If a gasket seal is disturbed while removing or adjusting gasketed parts, APV recommends installing a new gasket while reassembling. A proper seal is required to ensure optimum operation.4.2.1 Body Gasket TighteningIf after tightening body bolts, leakage continues, replacement of gasket is recommended. A new gasket is recommended anytime the valve is disassembled. The following procedure shown in 4.3 is recommended for the replacement of the gasket and other trim components. Also refer to Appendix A for torques.4.3 INSPECTION AND REPLACEMENT OF TRIM COMPONENTS Disassembly: -1.Place the valve in the half open position and remove all pressure and drain the system. Make sure that leakage of any residual material is caught in an appropriate container and disposed of properly.2.For gear operator or power actuator operated: - remove the bolt fastening the gearbox or power actuator. Remove the gear operator or power actuator. Remove the bolt fastening the yoke or yoke nut (depending on size/class).3. For lever operated: - remove the screw or fastening components of the lever. Remove the lever. Remove the retainer/lock washer and the stop plate.4.4 LEAKING FROM THE VALVE SEATa. After long-term valve operation and endurance of force, the resilience of the ball seat weakens, resulting in decreased pressure against the ball, thus leading to leakage. Further tightening the body bolts as per 4.2 above may tighten the seat seal further. Do not tighten more than torques shown in Appendix A.14 Flowturn - Installation, Operation and Maintenance Manual'