Another 2 tricks which help (a lot).
First: make sure your running a 3/8" or 7/16" center pin.
Replace the pins with grade 8 bolts. Make sure you have as much of the major diameter as possible, with the minimum amount of threads. This normally means you need to cut the bolt down. Next, install the bolt upside down: so that the head is on the top. You should do this, because the center pin almost always breaks at the main leaf, so that is where you want the major diameter of the bolt to me. And finally, secure the center pin with a top lock/stover nut.