Packing valves properly will substantially lengthen the cycle life of your packing. Improper installation procedure may cause leakage in high-pressure valves.
Too often, the required gland torque is estimated and not checked after initial tightening. If the packing is not loaded properly, only a small area of packing will be doing all of the sealing.
If the packing is not uniformly compressed, the contact pressure is eventually reduced, thus allowing packing to leak due to insufficient load.
Damaged packing or valve component damage due to leakage may prevent packing from ever attaining a proper seal.
Proper Valve Packing Procedure
Determine the proper torque for your application and valve. Torque the gland to the required level using the appropriate tools.
Cycle the stem up and down three times to set the packing.
Repeat steps 1 and 2 until gland torque is maintained.
Source - conval