my coach says that i pull back on my leg before it fully connects any tips?

If you're referring to the leg kick, please see the below video.

AIM THROUGH YOUR TARGET!!!! A very very very good way to help you visualize how to aim through. Is to have a guy stand up next to the thai bag leaning his hip and leg into it a bit. You line up faceing him and slightly to your right. When you kick you are aiming for his leg through the bag. Not just aiming to end the kick on the bag. Once you get this idea down. then it isn't to hard to tweek your thinking the bit it needs to simply aim through the guys leg.

My leg kicks aren't intended to "hit" the leg. They are thrown to cause maximum impact. I want to transfer every ounce of the force I put into the kick with my entire body. Into his leg via the impact point on my shin into his body. I use his body as my brake. Remember those retarded crash test dummy comercials? My leg is the car going 70mph. His leg is the brick wall. Do I hit the brakes??? HELL NO!!! I let his thigh, body, head do the stopping for me.

This bring to mind an often overlooked tid bit that I feel needs to be drilled along with the kicks. How to recover from a missed attempt. Some cats are fast enough to move completely out of the way. Some guys fire their kicks from too far out or telegraph then too much. Or a massive combination of all of the above with a dash of crap luck. The ballarina style pirouette you see thai practitioners do when they miss isn't just for pretty looks. It's entirely too complicated to really explain in words. Because there is a very fast series of movents required to pull it off well, keep you balance and return you to a defensible stnding position facing your opponent. And alot of these movents are dependent on the kickers build, agility and style. You watch enough fights and you'll see a few misses and how they recover. In all truth, any recovery that returns you back to a fighting position as fast as possible without you landing on your can is good in my book.

thanks for the tip i will try it tonight when i go to the gym

It is very important to kick through and not just to the target. Unlike in Tae Kwon Do, where you pivot on the front foot and snap out with the leg, in Muay Thai, the front foot steps out at a 45 degree angle and your body should naturally pivot with the angle of the foot. But use the momentum for you,not against you. use muscle and control to throw the leg like a baseball bat. The Thai Fighter's use Banana tree's to kick to harden their shins. I do not suggest this obviously. Kicking a pad will develop the muscle and prepare your body for the muscle trauma that awaits kicking another shin or leg, however, I would suggest getting a smooth glass bottle and fill it with water. Something small and first run it along the shin to "deaden" the nerves and then once you are comfortable with that(this is a multi-build-up month process). Then, start to tap at your shin with the bottle. Work your way up from there. This is a very serious muay thai fighter technique. Do not attempt unless you are very serious on fighting and using leg kicks like muay thai fighters do.

I have a tire tree I kick. I use a cardboard pillar mold with a cap on the bottom filled with sand bags. Around the cardboard tube you can just squeez economy car sized tired over it. The one I have is stacked 9 tires high. It's brutal.. but after two years of kicking it I can usually kick it full force 20 times each leg befor I don't want to anymore.