Graphite packing rope squeezes out between valve stem and packing nut

Question

I'm repairing an old brass hot water valve for my washing machine.  I've removed the old packing material and replaced it with new graphite packing rope.  I've tightened the packing nut until it is firm, but when I test the valve, water still leaks out between the nut and the valve stem.  When I continue tightening the packing nut, the graphite packing squeezes out between the valve stem and the packing nut, and the valve continues to leak.  What am I doing wrong?
(I have tried doing the recommended "wrap the packing rope twice around the stem".  I have also tried manually pushing the rope down into the void between the stem and the valve to minimize air gaps.  Neither approach seems to make a difference.)

Iggy · Answer

I agree with JACK, but that rope (graphite or Teflon/PTFE) is only meant to rejuvenate and not replace the packing. Your only bet with that stuff, since you've trashed the old packing, is to probably use the whole package and over-fill the entire packing nut.
Otherwise, you need a tight-to-the-stem flat washer to backup the rope. Ideally, you'd only want a Squared-Off Stem Washer, like JACK has displayed...tall and fat.
Or, if your packing nut is domed, you might find Beveled Washers are the only way to a long lasting watertight seal. Beveled Washers can be either angled or domed.

JACK · Answer

Using the graphite rope isn't as easy as you would think. First off, you need the right size rope that fits in tight with one wrap. You don't use a continuous piece. You cut a piece equal to the circumference and push the rope in and butt joint the ends. Then do it again with another piece of rope and rotate it so the ends don't even up with the previous layer ends of the rope. Keep doing this until the nut is full.
Better yet, get one of these kits. Picture from Granger.com

Graphite packing rope squeezes out between valve stem and packing nut

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