Two plumbing questions

HI there,
This site has been invaluable to me in solving some of my plumbing problems. First, thanks to all who responded to my question about drain leak after installing new bathroom sink. Problem solved! (thanks to you)

Question 1: I replaced the valve seat and stem in my hot water faucet for the tub. It is now very difficult to turn the tap on or off. What have I done wrong?

Question 2: I have a single shower diverter that is part of a 3 piece system. Hot water faucet, shower diverter, cold water faucet. The tub spout does not have the diverter on it.
The diverter drips from the part where you pull the knob out to turn the shower on. This drips when the water is on. Can this leak in behind the wall? and how do I solve this problem?

Thanks again to everyone. This site is brilliant!!!
K

Most older hot/cold stems have a packing nut. This would be the outermost nut you see when you remove the handle and trim. Put a little plumbers grease on the stem, loosen that a little, work the stem on and off several times to lube up the packing. Loosen and or tighten the packing nut just to the point that it turns easily, but does not drip.

You can replace the diverter stem, and you should check it soon, because it could be leaking behind the trim into the inside.