It's time to replace this, it's hard to turn when I shut the water off... and it does not shut it off all the way, it looks a bit complicated, can I just replace the part that I circled?


http://i.imgur.com/FxqLqF4.jpg


http://i.imgur.com/XA9ToRq.jpg

Remove the valve stem by unscrewing the large nut. Replace the washer. Remove the handle and the bonnet nut (small nut) Lubricate everything with plumber's water proof grease. Purchase some string graphite. Wrap several turns of the string graphite around the stem and reinstall the bonnet nut.

The graphite under the bonnet nut prevents leaks around the stem. As the bonnet nut is tightened it compresses the graphite. Over the years the bonnet nut has been tightened and is making the stem hard to turn. When reinstalling bonnet nut only tighten moderately. If it leaks you can tighten more.

The new washer may make the valve turn off completely or it may not. If the surface inside the valve is corroded it likely will not. If the problem is the washer only it will.

You probably can find a replacement valve but installing will be difficult.