Nice! If you are still inclined, you may be able to loosen everything up and get enough movement to clear your mud flap trim. I remember loosening it all up, including the 6 main mounting bolts and the smaller hardware on the bottom side of the step, and being able to move the boards to the rear just enough. If I remember correctly, the mounting brackets had to be angled just a bit to make it work. Then tighten it all back up. Hopefully it all works to your satisfaction.
Does anyone have the specs for '18 OEM SR5 running board bolts? I tried putting on the Trail Edition ones, and ended up ripping off one of the weld nuts inside the body. The threads/bolts are different!
The TE running boards, PT938-89200 shows a "M8x25 Serrated Flange Screw" vs "8mm Hex SEMS Bolt" described on T925-89100 (super detailed, I know).
The bolt kits are like $15 each side and hard to get, and I wonder if messed up the rest of the weld nuts by trying to strong arm these in (lol).
PSA: don't force the bolts in kids. Torque spec of only 14 lb-ft should have been my warning sign, but I just assumed the threads were dirty....
I know this is an old thread (and I need to get my stupid 15 posts in before I can post my own thread) but I do have a set of running boards for sale from a 2021 4Runner Off Road edition if anyone is interested.
__________________
2021 TRD Off Road, 1991 Wrangler on F150 axles, 37s, 5.13 gears.