putting in leaf spring u-bolts

Hey all. I bought some new u bolts to use with the new leaf springs i got. After taking the old spring out and putting the new one in, i got to the part wre i had to put the two ubolts in. I spent close to 2 hours messing with them until i fianlly got one in. I was woundering if there is a trick to getting them in. I did not expect it to be such a tight fit, but the car is within the standards of the u-bolt. Any help at all would be much appreciated, and would save me a good deal of hammering the crap out of the 2nd u-bolt :P.

Thanks
-Chris

How did you figure out what size to get the new bolts? Did you take one of the old one's in to match them? Do they match the old bolts exactly off the car?