Can you over tighten leaking sink fittings?

[davolson]

So last fall I had some leaking from the pipes going to the kitchen sink where the pex attaches to the base of the fixture. I had tightened them a "bunch" by hand and it only got worse. I finally backed them off a bit, and haven't had a problem since. Now I ended up removing the bathroom vanity fixture for another "problem" and on re-attaching the pex to the hot and cold inlets I again have a small leak/drip. My question is this: should they really be tightened about as hard as I can get them by hand, or even more with the channel locks, or just snug? Does the rubber washer insert get damaged or lose effectiveness if too tight? I read other threads on dripping sink fixtures and the answer was always just to tighten, but last time, doing that seemed to make it worse. Tips on proper technique appreciated!

[Rustic Eagle]

Initially just hand tighten "snug'", turn on the water check for leaks, and tighten slightly further by hand if required.

The plastic connectors on the PEX lines have a rubber 'cone seal' within them and are basically good for a single tightening application....., additional disconnect/reconnects are just borrowed time before a leak starts. Many problems start at the factory because they are overtightened and damage the cone seal.

RV dealership sell cone seals for these connections and I always keep a few on hand.

My factory damaged cone seal at the toilet connection, and the new cone seal.



New cone seal in place:



Bob