Bolt specs please - Rear bumper mounts (to frame)

Hello all !
I am replacing my stock taco chrome rear bumper with a high clearance bumper.
The 4 bolts (and 2 nuts) that mount the arms to the frame - does anyone know what size these are ? and what the torque spec ?
so far , the consensus I have found on torque is 59ft/lbs

I should replace these with Grade 8 , yes ?
M?

Thanks !

 

https://www.tacomaworld.com/threads/bolt-part-number.812225/

 

If I was really stuck I have used 7/16" out of the bolt bin.

If you pull on the bumper and do not have a hitch and can not find Metric Hardware grade 8 will work fine.

 

If they come out clean, I suppose I can re-use them, but they are over 20yrs old and a bit rusty. I would rather put in some bombproof new hardware, the new off-road bumper has a built in hitch receiver so I will be using this to tow or cargo.

 

Measure the ID of the hole Find bolts that have a snug fit get nuts flat washers and lock washers and your Good to go.

If you see Winter Chemicals Never Seize is your friend.