I have "saved" a few bolts using the cleaning method, and running a die over ends before trying to remove nuts. Usually requires a big pipe on wrench or heavy air gun to get off. Sometimes the bolt still breaks after you have half twisted it off with turning. In many cases with an older rig, the U-bolt stock itself is very rusty, maybe even half missing where it passes thru the flange. That may be why it broke in first place, rusted thru. AND. once I had one where the bolt spread way wide, and the old ones are hard to bend back. These things are BIG diameters, 5/8" or 3/4" or even bigger.
Flaps won't have them, maybe in little 1/2" lift kits or such, but Spring shops have them, or many truck places can now make them to your measurements in a short time. Call around places in Yellow Pages, save the gas!
