This is the delta scald guard tub and or shower faucet. As always make sure you have turned off the main water valve. If possible turn on a faucet lower then the faucet you will be repairing, so that if the main valve does not hold 100%, the water will run off in the lower faucet. Click on any image to see a larger image.
Remove the Delta button. You should be able to get your thumb nail under button and pull it out, If that does not work use a small screw driver to get it off. Then remove the screw in the middle of the handle, then the handle just pulls off.
This is what it will look like when the handle is removed.
The nut on the front of the faucet needs to be removed, This Is the most difficult part of this job, and the point where you can damage the faucet beyond repair. Put a wrench on the nut and try to turn it counter clockwise,
This is a side view, DO NOT USE TOO MUCH PRESSURE. If the nut does not move with minimum pressure, STOP. If the whole body starts to turn, STOP, you may have already damaged the faucet beyond repair. If the nut is too tight, stop and use the Answers Now link at the top of the page.
Now that the nut is removed the cartridge just pulls out if the bottom is not perfectly smooth, replace it with a new one.
With the cartridge removed you will be able to remove the rubber seats and springs, Make sure to replace both the springs and the seats. Note the direction of the seat and spring on the small screw driver, this is the way it needs to go back.
This is the front view with the hot seat and spring removed and the cold in place, nothing goes into the hole on the bottom of the valve. Now put the new springs and seats into the faucet. Note: putting a little plumbers grease on the rubber seats will make it work smother and help prevent leaks.
With the seats and springs back in place put some plumbers grease on the large O ring on the cartridge then push the cartridge into place. note the grove in the body, the cartridge can only go in one way, Now put plumbers grease on the threads on the shower body, so that the next time the nut needs to be removed, it will come off easy.
Adjust the set screw as the old one was or as you want it. If you have small children, adjust it so that the water will not be higher then 120 degrees F
Put the handle and button back on, turn the faucet you have on, off and turn the water on slowly. You are done.