Review on Pfister 9740440 Blue Ceramic Disk Cartridge Replacement - Efficient and Reliable by John Rocha

There is a major design flaw. The loud squeaking of the faucet is caused by air leaks from the side of the flat mating surfaces of the triangular assembly with three inlets for hot and cold water inlet and mixed water outlet. This is caused by limescale deposits on the mating surfaces and is made worse by the pressure in the intake ports, which is partially relieved by removing a small white plastic washer in the exhaust. If you don't have a water softening system, your only option is to disassemble the entire unit and soak it in vinegar overnight. The new disc cartridge offers a smooth surface on one side only. The disadvantage of the design is the lack of cheap and easily collapsible base and cartridge units in the mixer body.