Yesterday afternoon, I replaced the faulty cartridge in a Moen single-handle shower valve for a customer. I began by shutting off the water supply and carefully removing the existing cartridge. I then installed a new genuine Moen replacement cartridge, ensuring proper alignment and sealing. After reassembling the valve, I turned the water back on and tested the shower for smooth operation and leaks. The customer now has a fully functional, drip-free shower valve.