His u-bolt spring plates aren't bending because they're too thin. They're bending because they're flat. You can go one of two ways:

* Use a big flat piece of square that's about 1/2" thick. That so thick it probably won't bend, but it's a royal pain to drill through.

* Use thinner stuff and bend the ends up 45 degrees just outside of the u-bolt nuts. I've got 1/4" plate for my u-bolt flips at all 4 corners, and the plates haven't bent at all on a rearend beaten hard enough to crush the tube and bend the housing 5 degrees out of true.

If you're making them youselves, the easiest thing to do is just grind a notch 3/4 of the way through the plate where you want to bend it, stick in in the vise, and beat it over with a hammer. Then just fill in the notch with a welder.

Cut & paste this link to view it, but this 1/4" plate U-bolt flip cost me $25 worth of u-bolts and a little time...
http://www.pirate4x4.com/forum/attachment.php?attachmentid=206176&stc=1

Mounting the rear 13" travel shocks vertically instead of / \ like a lot of people do was also worth the time. Rides soooo much better that way. <img src="/forums/images/graemlins/wink.gif" alt="" />