Replacing a Delta Bathroom Faucet Cartridge

     Plumbers are expensive.  That's why I decided to replace the cartridge in my leaky bathroom faucet.  I should say "faucets" because I discovered the beginnings of a leak in the faucet of the second sink while fixing the first sink.  I assembled my photo tutorial using pictures from both faucet repairs.  Don't be confused by the left/right switches.

Step 1
The problem was not water leaking out the spout.  The water was leaking from the bottom of the faucet handle.  Water dripping from the spout usually means that the cartridge is worn out.  Water escaping from the handle usually means springs, seats, and O rings need to be replaced.  I decided to replace the whole shebang since this faucet is 10 years old.

Step 2
Gather an adjustable or channel lock wrench, needle nose pliers, an appropriately sized Allen wrench/hex key, and some old towels.  Then complete the most important step - turn off the water.  The shut off valves are under the sink.  Turn off both the hot and the cold sides.

Step 3
Faucet parts can be tiny, so it is important to close the drain stopper.  Your task will be oh so much harder if any parts go down the drain.  Once you have found the Allen wrench that fits, remove the set screw and pull off the faucet handle. 

You have exposed the cartridge and the nut that holds the cartridge down.

Step 4
Use the adjustable wrench or channel locks to remove the nut.  Turn counter clockwise.  It might be fused into place.  Add additional force gradually.

Step 5
Grab the cartridge with your needle nose pliers and pull it up and out.  Note the orientation of the cartridge, and sit it aside in the same position as it sat within the body of the faucet.  You'll see why this is important in Step 8.

Step 6
Use an old towel or rag to absorb any water in the hole.  Insert your finger, and you will find a round, plastic ridge in a well at the bottom of the hole.  This is the seat and there is a spring under this seat.  Use your needle nose pliers to grab the ring and seat and pull them out.

 Here is the old seat and spring.

Crusty Old Parts
Note the O ring on the cartridge.

Step 7
At this point, I used vinegar to remove the mineral deposits under the faucet handles.  They say not to use your finger nails as tools, but I scraped with my nails.  I didn't want to use a hard implement for scraping as that might have scratched the chrome.

Step 8
Cartridges come with a little plastic part that you insert.  Match the position of the plastic part in the new cartridge to the same part in the old cartridge.  The little plastic wedge controls the direction in which the handle turns (and I think whether hot or cold water comes out of the faucet) so you don't want to get this wrong..

Step 9
Place the spring inside the seat (wide end up and narrow end down).  Using the needle nose pliers, place the seat and spring in the well at the bottom of the hole.  You might have to apply some pressure with your finger to get these parts snuggley down into place.

Step 10
Drop in the new cartridge.  Note that the plastic tab on the cartridge must fit into the metal slot on the faucet body.  It might take a little pressure to push the cartridge down as far as it needs to go.

Step 11
Replace the nut tightening only with your fingers.  Once you have tightened it as far as it will go with your fingers, use the wrench to tighten just slightly more.  Tightening too much might damage the new O ring.  Now, replace the handle and tighten the set screw with the Allen wrench.  Turn on the water and check for leaks. 

     This repair cost $36.09.  Each cartridge cost $14.68.  A two pack of seats and springs cost $4.49.  Of course, there was sales tax.  You can get cheaper generic, plastic cartridges, but I decided to buy the brass parts sold at Lowe's that are designated as Delta replacement parts.