I've long wondered why they used reverse threads and a separate bushing to join the riser pipe. I kept the old, cleaned up mixing elbow along with the needed riser pipe in my spares until a couple years ago when I gave them to a to a guy just starting out with his young family on their two week vacation. I've been meaning to buy a replacement. After reading Gene's saga I'm thinking it's time to install a new one anyway. It's been a few years.