I want to restore the rear leaf springs of my f250 - and lowering them 2" or 2 1/2"...

But I'm afraid the bolts (not the U-bolts) rip of, when I remove them.
In germany maybe it is a problem to buy inch-bolts in special dimensions.
So I like to buy them, before I try to remove the springs.
Could anyone tell me the dimensions of them?
Thank you very much.
Regards
Volker