My mixer control is shown below. You simply rotate the handle to get the right temperature. On models that require you "pull out" first and then turn to "mix" this information probably will not be as helpful.
I needed the following tools:
Allen Wrench (only for handle set screw)
#2 Phillips Screwdriver
Standard Screwdriver (small)
Step 1: Safety First and Then an Ounce of Prevention
Next, turn off your water at the main inlet to your house and release the pressure by running a faucet nearest the mixer until there is no more running water.
Now an ounce of prevention, close the drain, plug the drain or cover the drain. Losing a screw down the drain would really make this a whole new kind of job with added trips to the plumbing supply or hardware store.
Step 2: Remove the Mixer Handle
Step 3: Remove the Nylon Guides
Step 4: Remove Cartridge Retaining Clip
The retaining clip must be removed completely and set aside.
Step 5: Pulling the Cartridge - the Hard Part
There is a lot of rubber surface area which may have grown attached to its surroundings inside the pipes. Getting the cartridge to start moving was a task. Most important, you do not want to break something inside the wall by prying or tugging too hard.
What I did:
I took the Nylon fittings and reversed the white ones so that they were longer by the length of the geared section, (back to back instead of front to back), then I placed them over the exposed spindle.
Next I placed the black Nylon piece into its original home, inserted the screw and slowly tightened. This created mechanical force between the pipe and the cartridge that literally leveraged the cartridge forward almost 0.25 of an inch.
Once the cartridge began to move, I removed the Nylon parts and set them aside again.
Now, using vice grips on the flats of the spindle I was able to pull straight out to remove the cartridge. This still took quite a bit of effort.
In the second image, you can see the cartridge almost free of the pipe.
Step 6: Fix or Replace
If you want to try a fix:
The next few steps are for taking apart the cartridge and there is no guarantee this is your problem or that it will fix anything. In fact, it may just finish off the cartridge completely, but at least you will know how the darn thing works. : )
Step 7: The Cartridge Exposed
Step 8: Dissasembly of the Cartridge
Once it starts to move it should become easier to slide out.
Remove the inside section completely as shown in the second photo.
Step 9: Remove the Plastic Retainer
Set the retainer to the side.
You can now try simply dumping the last part out of this section of the cartridge since the retainer is no longer there to keep it. However, if it does not freely fall out, this may be the problem with the cartridge.
Using a flat blade screwdriver, insert the screwdriver into the end where the retainer was and gently twist the inside section to break it loose. Next, using the holes along this unit, help the inside piece to come completely out.
Step 10: Clean Everything and Reverse the Process
If you came this far, hopefully you discovered that inner piece was stuck and causing problems. Now, you need to clean everything. You may want to soak the parts a few minutes in vinegar and then rinse with water before re-assembly. Keep in mind your water is still turned off and turning it on would be messy right now. I wiped my parts really well with a rag and was successful.
Simply reverse this whole process for re-assembly, pushing parts together and being careful not to bend, flex or otherwise do anything to break them. Applying some plumbers grease can make the re-assembly easier.
I hope this helps you as much as it helped me. : )
By the way, don't forget to double check everything and that the retaining clip is installed before you turn your water back on.
Now that you have a fully functional bath tub, get some candles and bubble bath for your valentine!