Just went through this for way too manyith time.
Easy solution, once you get the old ones out. I don't like the U bolts because they don't bottom solidly.
Get a piece of 3/4 X 3/16 or 1/4" steel bar.
Drill 2 holes in it spaced the same as the holes in the existing mount, clearance for 5/16" OD bolt.
Make spacer, or do like I did and stack up some 1/2" nuts on a bolt long enough to come through the bar, nuts, and frame mount plus a nylok nut.
Weld the bolt head to the bar, put on the nuts and weld to the bar and each other.
Drop in from the top of mount
Put on shock, flat washer and nylok nut
Took about 30 minutes to make and put in.