Kitchens – Removing Hose Attachment on Kohler Kitchen Faucet

Found a similar design at the Delta website. The round knurled piece should unscrew. The male threaded section should also unscrew. Apparently some have a hex shape to facilitate installation. Some have an internal female hex shape that is removed by an allen wrench. This allows the retaining plate to be removed. If there is enough room between the backsplash and the spout you could try holding the piece under the sink with a pipe-wrench, vise grips or large pliers and have someone spin the faucet.

I've done exactly this, including stripping the valve stem. You can remove it!

Most valves require a special wrench to unscrew. This is a cheap single-purpose tool; you probably won't be able to use an adjustable wrench or general purpose socket. Here's an example.

You'll slip this wrench over the valve stem and onto the valve body, then unscrew using a screwdriver stuck through the other end of the wrench. Make sure you have a snug fit with the correct size; there are two sizes in common use in the US and most valve wrenches have both.

As an alternative, it is possible there's a retaining nut holding in the valve. If this is the case, there would be a small ring just on the inside of the outer valve body. It would have notches to allow you to unscrew it using snap ring pliers (though you might be able to manage with a pair of needle nose pliers held at an angle). If this is the case, you should be able to see and move the locking ring. On the other hand, if you see a hex outline when you shine a flashlight down past the valve stem, you'll need the valve wrench.