Things You'll Need
Learning how to repair a Delta 1400 series Monitor tub and/or shower faucet should take only a few minutes, depending on your skill level. There are two similar Delta Monitor faucet designs, the 1300 and 1400 series. Both styles use the same Delta faucet cartridge, RP46074. Always use genuine Delta faucet parts if they are available to you. They will last longer than aftermarket versions.
Locate and close your home's main water shut-off valve. These valves are usually found near utility rooms, laundry rooms, in basements or out in the yard by the curb. If you are not sure where your home's shut-off valve is located, you can call your water company and ask them to temporarily turn off your water while you repair your Delta faucet. Open the Delta faucet and all the outside faucets around your home to drain any remaining water pressure from the plumbing system.
Remove the series 1400 Monitor faucet handle. Also remove the plastic acrylic handle; pop out the index button on the front of the faucet handle using a small flat-tip screwdriver. The index button is a flat plastic cap on the front of the faucet handle, usually marked with hot and cold indicators. Use a Phillips screwdriver to unscrew the handle retaining screw located under the index cap; slide the handle off the faucet stem. Remove the chrome trim from over the faucet body by pulling it straight back toward you.
Unscrew the faucet-cartridge bonnet nut by hand if possible; if not, use a plumber's strap wrench. The bonnet nut is the round brass or chrome-coated ring on the front end of the faucet manifold. Rotate the ring counterclockwise until removed. If the nut is difficult to remove due to mineral build-up or corrosion, wrap a cloth soaked in vinegar around it for 15-minute intervals until you can unscrew it easily.
Pull the shower faucet cartridge out of the manifold. You should be able to pull the cartridge out easily; if not, wiggle it to loosen it. If you still cannot remove the cartridge by hand, use a flat-blade screwdriver or sturdy putty knife to separate it from the faucet body.
Install a new Delta 1400 series Monitor pressure-balance faucet cartridge into the manifold. Make sure to line up the hot side of the cartridge to the left side of the faucet body. There are markings on the top of the faucet cartridge indicating which side of the cartridge is for hot water. Replace the bonnet nut, chrome trim and faucet handle. Turn the main water supply back on slowly. Turn off any open faucet. Test your Delta faucet for leaks and proper operation. When you turn the faucet on, the cold water should always start first.
If hot water comes out of the faucet before the cold water, rotate the faucet cartridge 180 degrees.
Do not use pipe wrenches to unscrew the bonnet nut -- you can easily warp the soft metal and ruin the faucet.