nuts on crash beam/bar

I am installing the rigid industries bumper mount kit for the 30 inch led bar and i need to undo the nuts that are on the outside of the part where the bar connect to the truck and i can not even begin to budge them. i have tried using a ratchet and a wrench and neither can move them with all my strength. are they spot welded or does anyone have any tips to get these suckers off? i just need the nuts off, not the whole bolt.
any help is appreciated.
P.s. I'm new to tacomas and tacoma world so cut me some slack

 

The nuts are flanged, and the bar is aluminum, so they tend to "bond" in place. I recently removed mine with my 3/8 impact wrench, if you don't have access to air tools, I'd suggest using a drift punch (or some sort of steel bar) and a hammer to smack the front side of the nut flange. This will help break the bond free. Some penetrating lube may help too, then lots of enthusiasm on the handle of an long ratchet or breaker bar. (Or a small pipe over top)

 

I'd go with breaker bar, the longer the better

 

I took mine off with a ratcheting breaker bar. That thing has been one of the best investments in terms of tools.

 

Which one do you have? The last one I had didn't last and it was awesome for the time it worked