leaky

I have a back outlet, floor mount toilet that leaked behind the wall. When I removed drywall, I saw that the connection between cast iron soil stack and the plastic connector is leaking. Please see photos. What is the proper way to connect the cast iron and plastic? Should I remove and replace...

http://imgur.com/a/JRZOP Here are pics of a shower valve I need to fix. It doesn't seem to shut all the way allowing water to drip steadily from the shower head. The shower head is Kohler, so there is a good chance that is the valve brand, but I'm not sure. I'm happy to provide any more...