Re-packing a valve - Always hard to turn after re-packing

[DAvid12846]

I need to replace the packing in a hot water in-line valve (not in a faucet). I've re-packed valves before, but afterwards, when I need to turn valves off, the valves turn very hard. Am I doing something wrong? It seems like the packing is compressed too hard against the stem.

Some of my older valves (1950's) have a conical shaped rubber washer with a metal washer underneath. When I re-pack these types of valves, should I re-pack with a new conical shaped rubber washer or should I use graphite rope? Is there a time to use Teflon rope instead of graphite rope?

David

 

[Jadnashua]

It sounds like you're tightening the nut too far. It only needs to be tight enough to prevent it from leaking...do not give it that extra turn just because you can. After a few days, if it seeps, tighten it a little more until it stops.

 

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[DAvid12846]

Thanks jadnashua.

Which is better for packing? Graphite or Teflon rope? Is the preferred material based on whether it is hot water or cold water?

For an old valve with conical shaped rubber packing and a metal washer, if I need to repack this type should I use another conical shaped piece? I think I have only one of these old iron valves with a conical shaped bonnet on the top. All my other valves, like the one I need to re-pack, have "flat" bonnets on the top.

David

 

[Jadnashua]

I do not have enough personal experience to tell you which packing works better in the long run. I do know from experience, that if I tighten the nut too hard, it just makes turning the shaft harder and harder, and usually doesn't prevent it from leaking, so don't crank it down...get it snug, and check...tighten slightly until it stops leaking. If the valve is designed to use a rubber packing, you want to use that.

 

[Asktom]

I prefer the graphite. Putting some silicone grease on the stem before you add the new packing also helps. But if you tighten it too much it will be hard to crank.

 

[Dj2]

"Some of my older valves (1950's)"

Nowadays you have more choices for angle stop/stop valves. Have you heard of the "1/4 turn valve"?

Do yourself a favor and stop relying on 67 year old valves to save your home from a flood if you happened to be out of the house, by replacing old stops with new, easier to operate and more reliable ones.

The great news is that these valve are very affordable. And oh, replace the supply lines too.