Ok, I don't know what your normal use of dicipline is but here is my advice:
1) Talk to your wife. Let her know what is wrong and why it eneds to change for BOTH children.
2) I don't know if you believe in spanking but do it if you do. For the 14 year old, he knows the rules, and he is not too old for a spanking. Take something thin like a tiny thing that goes on your drapes to move them or something, and give em a wack. 1 is all that's needed. For the 14 year old, spank him and ground him and keep him grounded.
List of things to do on the 14 year old:
First- Spank him and ground him. Keep him grounded. Ground him from something he loves the most FIRST... then take away something else if he keeps at it (while he is grounded). Third offense if he does it while still ground him, ground him from everything.
Second- next time he disobeys you ground him from everything on the spot for however long you see fit and spank him.
7 year old-
First- same as before
Second- Next tim he disobeys you, ground him from half things, then full. Time Out for 10 minutes to think about what he has done.
Third- same as second before.
or some kind of punishment on some scale. make it persistant, non changing.