[anijet]

When I raised our 3TK I added spacers to each end of each shock effectivly lengthing each shock the same amount I lifted the trailer. IIRC I made 5/8 inch spacers for a total of 1.25" extension. There is enough extra threads on each end of the shock to do this easily. We've done about 15,000 miles (over some very rough roads) this way with no problems.

Edit: The only reason the brackets are breaking is the shock is extending to its limit and the axle wants to go further. The brackets can't take this shock loading and will give. There is no way a properly functioning shock should be able to put enough force on the brackets to break them.