As everyone here, I had that problem.
The solution for me was very easy to read :
KEEP YOUR HEAD OVER THE BALL AT ALL THE TIME !
And that is it.
It may look like those pills that cure everything, but it really does cure a lot.
Because by keeping the head on top of the ball, you will lower the bowling shoulder, your spine will be tilted, it will promote a lot of good things.
Of course the long version would be:
"Well this is what works for me"
1. Hinge push-away in front of you
2. Make sure that on the way down you touch your body with your elbow (so there is no space between you and the arm).
3. On the top of the swing rotate the hand (open hand). Keep that hand position until the release.
4. On the way down try to touch the body with elbow again.
4. At the release point co-ck the hand and than let go (un co-ck).
5. Post the shot
You do that and you say goodbye to pulling.
Piece of cake, huh ?
PS: Joe Slowinski has some great articles. I suggest you read them.http://www.bowlingknowledge.info/images/stories/slowinskidec10.pdf