help with removing side mounting bracket

I'd verify there isnt a nut inside of tube tying to body mount bolt,
also look into receiver verify no other body rivet keeping it from sliding down -course that would mean receiver welded on in place-unlikely.
Other than that run a grinder or cut off wheel partially thru corner of lip to bottom to weaken, insert something into receiver to pry down...
Or reinstall and paint- just abandon.

Those look like they could be Torklift tiedowns made for no drill installation. Can't tell if front or rear.
The installation instructions should be online and they probably give you a hint. Do a web search for "20xx Tundra Torklift tiedowns installation instructions" and see if you find what you need. You could also go to their webpage torklift.com and find the tiedown part number for your truck and then search for the installation instructions for that part number.

Looks to me like they are welded on (picture 2). Think I'd leave them be and forget about them.

Thanks for help, I will look into torqlift tie down instructions. I don't see anything that looks welded?

I uploaded another pic, see below, that shows bolt/nut inside round tubing. It looks to be same as on truck that has no mount. Just to be sure, I sprayed nut w/ pb blaster and tried to loosen but it did not budge. Next step would be to use air impact wrench but I don't want to mess up anything, would rather leave attached...???

https://flic.kr/p/2awa4Nw

Yup its bolted (nutted) to body mount. Depth is closer (end of stud less) compared to stock. Looked at instructions to verify- it is a Torklift product.
http://www.hitchsource.com/docs/tl/T2305.pdf

Shows using factory nut on b/m stud...

AnEv942 wrote:
Yup its bolted (nutted) to body mount. Depth is closer (end of stud less) compared to stock. Looked at instructions to verify- it is a Torklift product.
http://www.hitchsource.com/docs/tl/T2305.pdf

Shows using factory nut on b/m stud...

Thanks, looks like I need to take air impact wrench to nut.

Unless there is access somehow to top of stud/bolt I'd hesitate using impact on it. Nut might break loose but stud might just spin. Noted end of stud is hex so intent is that is where tool would be used to keep from spinning. If I really wanted it off might go to the extra effort of cutting the tube to drop T/L mount, though doesn't look like room for a sazall...but then you could wrench end of stud...maybe.

Wonder if that whole body mount assembly unbolts- 2 bolts on ears?

Ok, I got nut loose with extra torque by hand, got bracket off, but stud does now spin. I put nut back on but can only tighten so far before stud spins. Picture below shows other side of mount where stud extends thru body?, no idea how to access unless I remove plastic cargo liner in cab maybe or take off whole body mount assembly as suggested by AnEv. Before I do that, what exactly does this stud do?

https://flic.kr/p/28TdMMw

I looked, the 2 'ear' bolts do hold the mount assy. but the main bolt goes in from top of floor- so loosening mount ears wouldnt help. Disregard that comment. The bolt holds body. Near as I can see torque is about 34lbs.
There are literlaly reams of information folks replacing Toyota body mounts.
Unless you can fab a tool to get to nut and still have access to end of bolt to hold, going to the effort of exposing bolt head from floor in the long run would be the easiest.

It was pretty easy to get access to top of bolt from inside cab, Thanks for all the help everyone.