Turn off the water supply to the shower
Open the shower handle to relieve pressure and let water drain out
Cover the drain (optional) to catch small parts
Remove the shower handle/trim:
Remove the handle screw (often under a cap)
Pull off the handle
Remove the trim plate/escutcheon
Remove the cartridge retaining hardware:
Unscrew the retaining nut (if present)
Remove any clip/retainer or packing/washer
Pull out the old cartridge:
Pull straight out if it releases easily
If stuck, use a cartridge puller or gently work it loose
Clean the valve seat and surrounding area:
Remove mineral buildup and old gasket material
Wipe the bore and check for damage or corrosion
Inspect and replace related parts if needed:
O-rings, seals, springs, and washers
Replace any worn or damaged components
Verify the new cartridge matches the old one:
Confirm orientation/part number
Ensure stems/slots align with the valve
Install the new cartridge:
Insert cartridge with correct orientation
Seat it fully into the valve body
Reinstall retaining components:
Install retaining nut/clip/retainer
Tighten snugly without overtightening
Reassemble trim and handle:
Reinstall escutcheon/trim plate
Reinstall handle
Set handle position so it matches the “off” position correctly
Turn on water supply
Test the shower:
Check for leaks around the handle/trim and cartridge area
Confirm hot/cold operation and smooth handle movement
If leaking persists:
Turn water off
Remove trim again
Check O-ring seating and cartridge orientation
Replace any compromised seals