Man this is so similar to what I've been going through. I noticed that my right arm was always way more pumped than the left, then my wife commented that my sleeves on my right arm were always tight and loose on the left. I measured and my right arm is over an inch larger than the left and it's almost all in the tricep.
I started paying attention to my form and realized that when I was doing any pressing excercises, my right arm was always taking over. I did a lot of close grip pressing for tri's and I'm convinced that's what did it. My right arm was doing the bulk of the work and the left was basically just assisting.
About a month ago I started doing only dumbbell work and paying really close attention to my form. I think that's the key. I never realized that my right arm was working so much harder so I tried to focus on always locking out my left arm and making a good mind/muscle connection. It helped a lot, but the right arm is still significantly bigger. So now I'm only working the left arm and doing nothing for the right except what I get from heavy DB bench and overhead pressing. I haven't lost any size in the right and the left is catching up much faster. It's mentally hard to ignore one whole arm, but I think it will be worth it.
Also, I was convinced that my left wrist was weaker than the right because when I would bench heavy, my left wrist would bend back and the right was always straight. Turns out it was just weak and since I've focused on getting the left size stronger, it's straightened out.