Problem: Water runs from the tub spout even after I turn the shower diverter handle as far as it will go. So, I removed the middle compression type diverter assembly and replaced the rubber washer under the end screw. I soaked the assembly in vinegar and scrubbed it with a toothbrush to remove the green and white build-up. I did not change the "hard yellowing" O-ring because the person at Home Depo told me I didn't need to (and it seems almost cemented on). Lastly, the middle stem piece will completely turn inside the locknut part when I hold the assembly in my hands. However, each time I put the complete assembly back into the wall, the diverter handle will only turn 3/4 of the way. Do I need to replace the entire diverter assembly to fix my problem? Please help!