Repairing a Delta Monitor shower faucet to stop leaking or improper water flow requires about an hour. It involves replacing the cartridge inside the faucet that monitors water flow and mixes the hot and cold water. If you have any plumbing experience, this repair will be simple. However, if you are new to faucet repairs, approach this job with care and patience. Once you master the finer points, the process becomes much easier.
Shut off the water to the house.
Remove the set screw in the side lever handle with an Allen wrench, after taking off the small cap on the end of the handle. Take off the temperature control knob and remove the screw in the rotation limit stop (for scald-guard faucets) with the Allen wrench.
Slide off the trim sleeve, the round O-ring and bonnet. Use a pair of channel-lock pliers to remove the bonnet if it is stuck because of sediment.
Pull the cartridge straight back to remove it from the faucet head. Grip the top of the stem with your pliers if this part is stuck in the faucet.
Insert new seat springs into the back of the new replacement cartridge, after coating them with plumber's grease. Install the cartridge into the faucet head by pushing it firmly into the fixture.
Reassemble the faucet by replacing the trim sleeve and bonnet, reattaching the side handle and tightening the screw, and then replacing the stop limit and temperature control knob.