Plumbing Questions? Ask a Plumbing Expert.
hi I am dan and I can help you with this. first have you removed the handle and see the top of the cartridge?
there is a small set screw on the bottom of the handle it will require a small allen wrench to loosen it and pulls off the stem then the chrome cover comes off and you can tighten the cartridge nut. is the handle loose? is it leaking?
did that answer your question or do you still need help with this?