Compression Faucets

• The Kohler K-394 bathroom sink faucet uses compression and valve stems to regulate the rate of the flow of water through the faucet. Both valve stems’ tips fit inside the faucet’s water control handles, so when you turn the handle, the valve stem turns as well. Each valve stem has rubber washers or seals that wear out and become brittle over time. The brittle rubber seals develop cracks, allowing water to seep through the seal and leading to leaks.
  
  

Valve Stem Removal

• You must always start the repair process by shutting off the water to the faucet; otherwise, once you start taking off parts, water will flow freely out of the handle area. You may either close the valves under the sink by turning the handles clockwise, or you can close the house’s main water valve. If you are not sure which valve stem is the source of a leak, feel the temperature of the leaking water first to determine whether it is hot or cold, indicating which side is the source of the leak. You must remove the screw that holds the control handle in place and then use an adjustable wrench to remove the retaining nut from the valve stem. You then must turn the valve stem counterclockwise to remove it from the faucet.
  
  

Servicing the Valve Stem

• With the valve stem removed, you must undo the screw on the end so you can start sliding off the various parts of the stem. Remember in what order and orientation the different parts sat, because if you put the parts back in the wrong order or orientation, the faucet could leak more than before. You must purchase rubber seals made for the K-394, or else the faucet will leak or the valve stem will not fit in the faucet correctly. Also, you must coat the new seals with plumber’s grease so they last longer. If you notice the metal seat is pitted, replace that as well.
  
  

Stopper Leaks

• The Kohler K394 also comes with a pop-up stopper mechanism that may develop leaks over time. You must pull the stopper out of the drain to examine the rubber seal on the underside of the stopper’s lip, since the rubber seal may warp or crack with age. To remove the stopper, you need to unscrew the retaining nut on the sink’s drain tailpiece and then pull out the pivot rod inserted in the tailpiece since the pivot rod holds the stopper in the drain. You may find a new rubber seal at your local plumbing supply store.