I'm looking to stop my stopcock leaking. It's a steady seeping rather than a drip, but it's only going to get worse. My question is can I just turn off the stopcock and loosen the glandnut to see if I need to add some P.T.F.E. tape? You'll see from the attached where the water is coming from, but I wanted to check I could isolate the water supply by turning off the stopcock and then remove the glandnut to repair the P.T.F.E. tape or waher etc.