Plastic water valve question ...again

[M.Burns]

I have a standard plastic water valve in a rental property that is leaking past the stem. I see where it may have been possible to tighten the packing nut, but there are ribs on the outside of the valve, parallel with the stem, now preventing it from being tightend any further. Are plastic valves repairable? If I remove the circular handle, and then back off and slip the the packing nut over the stem, what is inside a plastic valve? Does it seal by using an o-ring that slips over the stem and is compressed by the packing nut? I assume it doesn't contain regular packing material or what might be found in a brass valve. Advise and thanks M.B.

[Rich Greenberg]

What I would try is to shut the water off, remove the packing nut, and see whats inside. Repair/replace if possible. If you can find an identical new valve, then you could swap out the stem/handle to the old valve body.

[No]

You could probably have pulled off the nut and looked faster than posting here. if you can get the nut off, what could it hurt to try and add some packing, even if none existed before? Worst case you cut off the valve and put on a new one. Costs just a couple of bucks. You may need to couple in some more pipe to make up the length. Still not that big a deal.

[M.Burns]

Yes, I suppose I could have tore into the valve first, but the purpose of the post was for someone to respond who has done this before, and is familiar with the internals of a plastic valve. Right now it's dripping occasional on a basement floor. Once I go for it and it's not easily repairable, then I have a worse situation ...since the valve is in cramped quarters and would be an s.o.b. to replace. That's why I asked first.

[BobK207]

the problem is is, it is very hard to diagnose from the keyboard.......some plastic valves are repaiable some are not

is it a gate, a globle or a ball valve? a hose bib?

soem palstic valves have packing, some jsut a stem O-ring

any chance of a picture?

per Rich's suggest

"If you can find an identical new valve" (or similar) you could use it as a repair guide

cheers Bob

[George E. Cawthon]

The best deal would be to get a plastic valve just like you have and take it apart to see how it works. In any case, most simple plastic valves are just like their metal counterparts. So, just apply light pressure 1-2 fingers worth to turn the packing nut 1/8 of a turn and see if that stops the leak. If you can't tighten the packing nut with just light pressure then try to turn it the opposite way with light pressure. If it turns, then turn the water supply valves off (just for safety) open a cold water and a hot water tap to relieve pressure. Loosen the nut and move it up on the stem and add a couple of turns of packing material (graphite or Teflon, it doesn't matter), tighten the packing nut (not all the way), turn the water on, and tighten the packing nut until the leak stops.

I don't know what the specs are but I would stay under 50 inch-pounds on the packing nut.