Gas shutoff/check valves leaking

Diagnosing a CO2 leak on my 3 tap system, I found the manifold inlet and plug at the end both leaked. This was an easy fix with teflon tape and a wire wheel to remove the old tape. Then I noticed that two of my shutoff/check valves leaked from the side with the red rubber handle on it when in the open position. No leaks, however, in the closed position. I only have one keg tapped at present, and have ordered two new valves. I was just wondering if anybody else has had problems with these (cheap-looking) little valves?

is it leaking from the valve stem where the handle attaches, or the end of the valve?
If the stem is leaking you can just remove the handle and tighten the packing nut gently.

They are leaking from the valve stem. I took off the handles and there is no packing nut underneath. I was tightening the nut that holds the handle on the stem and stripped the threads. Are these junk, or was I just being too rammy?

Sounds like they might be junk but if you could post a close up picture of the valve I'd have a better idea.

Where were these from? I discovered my new co2 setup from KC completely empty after 2 weeks of slow draining that I was unable to detect.

I've a pesky slow leak as well.

Haven't checked the shut-off valves though...

Sorry, but I've been out of town. Here's a picture of the valves that were leaking. The leak was coming from the valve itself, under the handle. It's worthwhile checking these valves if you have a leak you can't find. New valves arrived, are installed, and appear to be okay. the new valves have a shiny body, as opposed to the matte finish on the old ones.