Spears Gate Valve - Leaking at Stem

[Kestrell]

I've finally finished the plumbing on my 125gal and everything is looking good, except for a very small drip leak on the gate valve. It's coming from between the bonnet nut and the stem, arrow in blue:

I've tried tightening the bonnet nut but it still has a small drip. I'm not sure if I just need to tighten that further, or if there is something else I need to tighten/adjust?

Thanks

 

[exnisstech]

It looks like it uses an oring as a seal. O rings don't really need much compression to form a seal and will be damaged and cause leaks from being over compressed. You could try tightening it some more but if that doesn't fix it I would probably replace the oring and inspect the stem for any damage / defects. I'm applying auto tech mentality so it may or may not apply to gate valves

 

[Kestrell]

It looks like it uses an oring as a seal. O rings don't really need much compression to form a seal and will be damaged and cause leaks from being over compressed. You could try tightening it some more but if that doesn't fix it I would probably replace the oring and inspect the stem for any damage / defects. I'm applying auto tech mentality so it may or may not apply to gate valves

Got it worked out. I noticed it was only dripping when partially open, and did not drip when fully open or fully closed. So the o ring was sealing, just not all the way when only partially compressed by the stem. I went to the hardware store which was thankfully open today (labour day) and got some silicone grease. After applying that and putting it all back together, no more leak!

Thanks for the help.