Review on Pfister 9740420: High-Performance Pressure Balanced Valve Cartridge Sub Assembly by Jojo Howell

Before ordering a replacement I turned off the water and opened the valve to see what was inside. We had an old two piece design (971-250 + 974-291). The water was slowly seeping out of the control stem and while I'm pretty sure the valve stem would solve the problem, the o-rings on the other part were pretty worn. I chose to order this rather than pay more to have both parts replaced. The solution was quick and easy and has worked well so far. Doesn't drip, spins nice and evenly. The only tricky part was getting rid of any mineral buildup that had built up during draining (I used lime juice and scraped gently). Everything is like new and costs a lot less than calling a plumber.